A New Induction Motor Vf Control Method Capable of High-Performance Regulation at Low Speeds file_1
杰克逊电子气体计量仪手册说明书
FUNDAMENTAL PRINCIPLES OF GAS TURBINE METERSRobert BennettElster Meter Services2221 Industrial RoadNebraska City, NE 68410INTRODUCTIONGas measurement in the U.S. and around the world is dominated by diaphragm, rotary, turbine, and orifice meters. Each serves a different segment of the gas industry and each has its own set of advantages and disadvantages.These four main types of meters can be broken into two distinct categories: positive displacement, and inferential. Diaphragm and rotary meters fall into the positive displacement group because they have well-defined measurement compartments that alternately fill and empty as the meter rotates. By knowing the volume displaced in each meter revolution and by applying the proper gear ratio, the meter will read directly in cubic feet or cubic meters. Turbine and orifice meters have no measurement compartments to trap and then release the gas. These meters are categorized as inferential meters in that the volume passed through them is "inferred" by something else observed or measured. n the orifice meter the volumes are determined only by knowing the inlet pressure, differential pressure, plate size, and piping characteristics, all of which "infer" the flow rates that in turn can be integrated over time to provide the volume.Turbine meters, also called velocity meters, "infer" the volume of gas passing through them by measuring the velocity of the gas stream. Gas moving through the meter impinges on a bladed rotor resulting in a rotational speed that is proportional to the flow rate. The volume is determined by counting the number of meter rotations. The purpose of this paper is to provide an overview for the installation, maintenance, and proving of axial flow type turbine meters. THEORY OF OPERATIONAs defined in A.G.A. Report #7, the turbine meter consists of three basic components (See Figure 1 and 1A)1. The body which houses all of the parts andphysically contains the gas pressure.2. The measuring mechanism consisting of therotor, rotor shaft, bearings, and necessary supporting structure.3. The output and readout device which may beeither a mechanical drive to transmit the indicated meter revolutions outside the body for uncorrected volume registrations or for electrical pulse meters, it would be the pulse detector system and all electrical connections needed to transmit the pulses outside.Figure 1.Figure 1AGas entering the meter increases in velocity as it flows through the annular passage formed by the nose cone or upstream stator and the interior of the body. The movement of the gas over the angled rotor blades exerts a force to the rotor causing it to rotate. The ideal rotational speed of the rotor is directly proportional to the flow rate of the gas. The actual rotational speed is a function of the annular passageway size and shape, and rotor design. It is also dependent on the load that is imposed due to internal mechanical friction, fluid drag, external loading, and gas density.INSTALLATIONA.G.A. Report #7 was written to provide recommendations as to the correct method for installing turbine meters, using their associated corrective factors, and meeting the operating requirements that pertain to axial flow type meters. Since the turbine meter is a velocity-measuring device, consideration should be given to both the upstream and downstream piping to insure a uniform velocity distribution of the gas through the meter and the rotor by reducing jetting or swirl. Construction of the turbine meter is such so as to minimize minor flow distortions that could affect meter performance. Straightening vanes are recommended to eliminate swirls. These vanes or any type of integral flow conditioner will not remove any jetting actions and may actually enhance the jetting effect. The recommended installation (See Figure 2) for in-line turbine meters calls for a straight length of 10 pipe diameters upstream with a distance of 5 pipe diameters between the end of the straightening vanes and the meter inlet.A length of 5 pipe diameters is recommended downstream. Both inlet and outlet pipe should be the same size as the meter. Upstream piping should be clean with no obstructions from flange gaskets, pressure taps, etc. The pressure tap should come from the meter as specified by the manufacturer while the temperature well, if required, should be 2.5 pipe diameters downstream from the meter.Figure 2. AGA Recommended InstallationRestricting and/or throttling devices, such as partially opened valves or regulators, are not recommended in close proximity to the meter since they tend to increase jetting and swirl. When necessary, any such throttling device should be installed an additional 8 nominal pipe diameters upstream or 2 diameters downstream from the meter.I n addition to the recommended installation, alternative types of installations are allowed where there are space limitations with the understanding that there may be some associated loss in meter accuracy because of jetting and swirl.Short coupled installations (See Figure 3) use a minimum of 4 nominal pipe diameters upstream with the straightening vanes located at the inlet of the piping. The distance between the end of the straightening vanes and the inlet of the meter should be at least 2 nominal pipe diameters. The meter run is connected to the vertical risers with standard tees or elbows.Reducing fittings may be used at the tee or elbow but only one pipe size reduction is recommended. Valves, regulators, strainers, or filters should be installed on the risersFigure 3. Short Coupled InstallationClose-coupled installations are shown in Figure 4. The meter design must incorporate integral flow conditioners upstream of the rotor. The meter is connected to the risers with a tee or elbow and the maximum reduction recommended is one pipe size. Any valves, regulators, strainers, or filters must beinstalled on the risers.Figure 4. Close Coupled Installation Recommendations for angle body turbine meter installations are shown in Figure 5. The meter run is connected to the inlet riser with either a 90-degree elbow or tee that may be reduced by one pipe size if necessary. With straightening vanes, the length of the upstream piping may be 5 pipe diameters with at least 2 pipe diameters between the end of the straightening vanes and the inlet to the meter.Without straightening vanes, the upstream piping should be at lease 10 pipe diameters long. Any valves, regulators, strainers, or filters should be on the risersFigure 5. Angle Body InstallationINSTALLATION CONSIDERATIONSTo protect the turbine meter from the dust, dirt, and scale that may occur during certain system operations, it is important that either a strainer or filter be installed upstream of the meter to increase its bearing life. Filters can trap small dust particles down to 10 microns. A differential pressure gauge should be installed across the filter or strainers to indicate excessive pressure drops from a build up of foreign matter in the strainer screen or filter element. All foreign material in the upstream piping should be removed before installing the measuring element and placing the meter in service. Special consideration should be given to the pipe between the strainer and/or filter since it may contain debris that will not have been removed.Since upstream disturbances should be kept to a minimum, temperature wells should be installed downstream of the meter at a recommended distance of between 2 and 5 pipe diameters downstream. Because regulators or any throttling device may tend to cool the gas stream as it expands, the temperature well should be installed ahead of any valve or flow restrictor that may be downstream of the meter.Pressure taps provided by the manufacturer on the meter body should be used as pressure taps for any recording or integrating instruments and during calibration. Use of any other tap locations may change the meter's calibration curve.I n any area where liquid contaminants are suspected a separator and/or drip tank should be considered since a high velocity liquid slug can cause damage to the rotor.Figure 6. Turbine Meter InstallationOver-range protection to prevent the meter from overspeeding may be needed. Although it may be operated up to 150% of the rated capacity for short periods of time, it is a good practice to limit the meter to approximately 120% of its maximum capacity. Either a critical flow orifice or sonic venturi nozzle may be used downstream of the meter provided that adequate pressure is available to compensate for the permanent pressure loss across the flow limitor. There is about a 50% pressure drop across critical flow orifices and between 10% to 20% drop with a sonic flow nozzle.Blow down valves should be installed downstream of the meter and should be no bigger that 1/6 of the meter sizeMeter Size Blow Down Valve2"1/4"3", 4" 1/2"6", 8", 12" 1"A good design for a turbine meter installation incorporating many of these recommendations would look very similar to Figure 6.INSTALLATION CHECK LIST-Meter is sized properly for line pressure and load-Meter has been lubricated-I nstallation is in accordance with A.G.A. #7 recommendation and/or company standards-Inlet and outlet meter connections are concentric to the pipe flanges and gaskets do not protrude into the flow pattern-Filters, strainers, and associated equipment are provided where required-Meter can be isolated and by-passed if needed-Pressure blow down is sized properly and located downstream-Provisions are made for in-line testing-Pressure and/or temperature taps are provided if required-No welding should be done with the internal mechanism in the meter-I f hydrostatic testing is done, a spool piece is recommended MAINTENANCE/FIELD TESTSNormal maintenance and field tests consist of lubrication, internal inspection, and spin testing. Prior to putting the meter in service, make sure it is lubricated and perform an initial spin test that will provide a reference time to future test results.Most turbine meters have provisions for a pressurized lubrication system. This consists of an external alemite fitting and lever-type oil gun which permits lubrication without taking the meter out of service. This is a simple procedure and in addition to replenishing the oil supply, it also flushes the bearing with fresh oil. Older style gravity lubrication systems can be converted to pressure systems, check with the manufacturer for correct parts.The frequency of lubrication is a function of the operating conditions. Obviously, a meter subject to gas containing dust and/or liquid contaminants or running at elevated capacities and/or extended periods should be serviced more frequently. Manufacturers suggest monthly lubrication with the period extended as experience permits. Lubrication of the meter with an approved oil is a good, relatively inexpensive form of preventive maintenance. Periodic internal inspection of the meter should be performed to ensure that components are in good working condition. The frequency of inspection is dependent on the severity of the service but should be done annually.Follow recommended procedures for taking the meter out of service and remove any readout devices.After bypassing if necessary, and isolating the meter, relieve the internal pressure using the blow-down valve. Once the internal mechanism is removed, visually inspect the interior of the meter body checking the internal flow guides or vanes for damage and removing any liquids or debris. Check the inside of the inlet and outlet flanges along with the gaskets to make sure they are in proper alignment and not interfering with smooth gas flow. Also inspect any seal tape within the body for any cuts or tears. This seal tape prevents gas from bypassing the annular passage through the rotor. Check the internal mechanism flow passages and rotor for damage. The rotor should be checked thoroughly for accumulation of dirt, wear, missing blades, or other damage. Since it is the essential measuring element, any rotor with more than superficial damage should be replaced and the meter proved. After completing the visualinspection, the mechanism should be spin tested to determine its condition.This test determines the relative condition of the meter and is not an accuracy test. With the cartridge place in a draft-free area and in its normal operating position, place suitable material against the side away from the rotor and with a finger or air jet; spin the rotor briskly, time how long it takes the rotor to come to a complete stop, and record this time. Repeat this procedure three times to come up with an average spin time. Compare this average time with the tables provided by the manufacturer for each size meter. This average spin time should also be compared with the initial spin test done when the meter was first installed.f the spin time has not changed significantly, the meter is clean, and the internal parts show no damage; then the meter should not display any change in its accuracy. I f the mechanical friction has increased, the resultant slower spin times indicate that the accuracy of the meter at low flow rates has degraded. I f decreased spin time is encountered, the meter should be lubricated and the rotor spun-in to throw off any excess oil which can also contribute to slow spin times. The spin test should be redone to determine if acceptable times can now be achieved.Whether the spin time is acceptable or not, it is a good practice to also check the intermediate gear train for binds. If possible, another spin test should be run with the readout device in place to also check it for binds that can affect low flow accuracy.Another factor that can contribute to low spin time is low ambient temperatures. Even though the oil is a light viscosity, low temperatures affect it.MAINTENANCE CHECKLIST-Meter should be lubricated on a scheduled time period with recommended oil-Filters or strainers should be checked for differential and/or pressure drop-Before disassembly, make sure the meter is depressurized and the readout device is removed.-Check the interior of the meter including seal tape, guides, and/or vanes for damage and remove any liquids and/or debris-Check the cartridge flow passages and rotor for damage-Conduct the spin test in a draft-free area.Perform three repetitions and average the spin times.-f low spin time is encountered, lubricate the bearings, and spin the rotor several times to work the new oil in, and repeat the test-Check the intermediate gear and readout device for binds-Spin test with the readout device in place PROVINGAs stated earlier, the spin test is not an accuracy test but rather a means to determine the relative condition of the meter.I n order to determine the accuracy of any meter, it must be compared to a recognized standard. While there are several standards available such as low pressure flow proving, sonic nozzle proving, bell proving, and transfer proving, the last two are the most prevalent in the gas industry.Because of the high flow rates associated with turbine meters, bell provers are not generally used for shop proving. However, manufacturers use large bell provers, 350 cf or 500 cf for special test and establishment of master meters by a process known as cascading. In this process, an engineering curve (15 points) is established for a 4" meter. Using the 4" meter as the master meter, an engineering curve is established for a 6" meter, 8" meter, and 12" meter. All of these tests are traceable to the National Bureau of Standards. These master meters are then used to transfer prove production meters and determine the normal six (6) point curve furnished with each meter.Field or shop transfer provers are also calibrated using an accepted standard and a thoroughly defined accuracy curve which is traceable to National Bureau of Standards that has been derived and furnished with each prover.Normally a transfer prover system consists of the master meter, control console, flow rate control valve, pulse transmitter of gate switch for both master and field meters, blower with muffler, and associated pressure and temperature sensors (Figure 7). The connection between the master meter and the field prover is either fixed piping or flexible hose with quick disconnect couplings. Vacuum testing with air drawn through both master and field meters is the common method used. In this procedure, the same volume of air is passed throughboth meters. By comparing this volume and applying master meter presets, along with corrections for pressure and temperature differences, the accuracy of the field meter can be calculated.Figure 7 Transfer ProvingOne method of proving turbine meter cartridges is to start an exchange program. A cartridge is tested in the shop, then taken to the field where it is exchanged with the field meter cartridge. The field meter cartridge is returned to the shop, where an in-test (as found) is done, any necessary repairs made,cartridge retested, and a new accuracy curve is generated. This cartridge is then used for field exchange on another meter.This method offers the advantage of only having the meter out of service long enough to exchange cartridges. Meter manufacturers state maximum error for this exchange method is +/- .25%(American) and +/- .6% (Equimeter). PROVING CHECKLIST-Purge meter observing safety rules and proper procedures-I nstall pulse transmitter on field meter, place temperature sensor as close to field meter outlet as possible-Connect pressure tubing to tap provided for this purpose on the meter-Leak test piping; if in-line proving, make sure valves are not leaking through-Observe prover manufacturer's instructions for initiating prover, self-test, and actual test sequence-Record results and calculate corrected proof -Perform periodic maintenance and re-certification of the transfer proverREFERENCES-Measurement of Gas by Turbine Meters,Transmission Measurement Committee Report No. 7, American Gas Association, 2006-Gas Measurement Manual, Part 4 Gas Turbine Metering, American Gas Association, 1985 -Gas Measurement Manual, Part 12, Meter Proving, American Gas Association, 1978 -Mm-1070, Rev 2, Equimeter MK-I I and AAT Turbo-Meter I nstallation and Maintenance Instructions-A I M 4700, Maintenance of American Gas Turbine Meters, American Meter Company -AI M 4701/AIM 330.2C, Gas Turbine Lubrication Instructions, American Meter Company。
高速切换半导体控制器使用说明说明书
1. When studying how to use our invertersNotesLeakage currentThis inverter uses high-speed switching semiconductors for PWM control.When a relatively long cable is used for power supply to an inverter, current may leak from the cable or the motor to the ground because of its capacitance, adversely affecting peripheral equipment. The intensity of such a leakage current depends on the PWM carrier frequency setting, the lengths of the input and output cables, etc., of the inverter. To prevent current leakage, it is recommended to take the following measures. [Effects of leakage current]Leakage current which increases when an inverter is used may pass through the following routes:Route (1) ... L eakage due to the capacitance between the ground and the noise reduction fi lterRoute (2) ... L eakage due to the capacitance between the ground and the inverterRoute (3) ... L eakage due to the capacitance between ground and the cable connecting the inverter and the motorRoute (4) ... L eakage due to the capacitance of the cable connecting the motor and an inverter in another power distribution lineRoute (5) ... L eakage through the grounding line common to motorsRoute (6) ... L eakage to another line because of the capacitance of the groundLeakage current which passes through the above routes may cause the following trouble.l M alfunction of a leakage circuit breaker(ELCB) in the same or another power distribution linel M alfunction of a ground-relay installed in the same or another power distribution linel N oise produced at the output of an electronic device in another power distribution linel A ctivation of an external thermal relay installed between the inverter and the motor, at acurrent below the rate current[Measures against effects of leakage current]The measures against the effects of leakage current are as follows:1) Measures to prevent the malfunction of leakage circuit breakers(ELCB)(1) Decrease the PWM carrier frequency of the inverter. Note)(2) Use radio-frequency interference-proof ELCBs as ground-fault interrupters in notonly the system into which the inverter is incorporated but also other systems. When ELCBs are used, the PWM carrier frequency needs to be increased to operate the inverter.(3) When connecting multiple inverters to a single ELCB, use an ELCB with a high currentsensitivity or reduce the number of inverters connected to the ELCB.2) Measures against malfunction of ground-fault relay:(1) Decrease the PWM carrier frequency of the inverter. Note)(2) Install ground-fault relays with a high-frequency protective function in both the sameand other lines. When ELCBs are used, the PWM carrier frequency needs to beincreased to operate the inverter.3) Measures against noise produced by other electric and electronic systems:(1) Separate the grounding line of the inverter from that of the affected electric andelectronic systems.(2) Decrease the PWM carrier frequency of the inverter. Note)4) Measures against malfunction of external thermal relays:(1) Remove the external thermal relay and use the electronic thermal function of theinverter instead of it. (Unapplicable to cases where a single inverter is used to drive more than one motor. Refer to the instruction manual for measures to be taken when thermal relays cannot be removed.)(2) Decrease the PWM carrier frequency of the inverter. Note)5) Measures by means of wiring and grounding(1) Use a grounding wire as large as possible.(2) Separate the inverter's grounding wire from that of other systems or install thegrounding wire of each system separately to the grounding point.(3) Ground (shield) the main circuit wires with metallic conduits.(4) Use the shortest possible cables to connect the inverter to the motor.(5) If the inverter has a high-attenuation EMC noise reduction fi lter, change the groundingcapacitor switch to reduce the leakage current. Note that doing so leads to a reduction in the noise attenuating effect.Note) I n the case of this inverter, the PWM carrier frequency can be decreased to 2.0kHz.Decreasing the carrier frequency results in an increase in electromagnetic noise from the motor.Ground faultBefore beginning operation, thoroughly check the wiring between the motor and the inverter for incorrect wiring or short circuits. Do not ground the neutral point of anystar-connected motor.Radio interference[Noise produced by inverters]Since this inverter performs PWM control, it produces noise and sometimes affects nearby instrumental devices, electrical and electronic systems, etc. The effects of noise greatly vary with the noise resistance of each individual device, its wiring condition, the distance between it and the inverter, etc.[Measures against noises]According to the route through which noise is transmitted, the noises produced by an inverter are classifi ed into transmission noise, induction noise and radiation noise.PWM waveform. In addition, the cooling becomes less effective at low speed, so the torquemust be reduced according to the frequency. Regarding the allowable torque characteristic,please confi rm its motor manufacturer.When constant-torque operation must be performed at low speeds, use a Toshiba VFmotor designed specifi cally for use with inverters.Starting characteristicsWhen a motor is driven by an inverter, its operation is restricted by the inverter’soverload current rating, so the starting characteristic is different from those obtained fromcommercial power supply operation.Although the starting torque is smaller with an inverter than with the commercial powersupply, a high starting torque can be produced at low speeds by adjusting the V/f pat-tern torque boost amount or by employing vector control. When a larger starting torqueis necessary, select an inverter with a larger capacity and examine the possibility ofincreasing the motor capacity.3. When installing, wiring and operating the inverterInstalling and wiringInstalling precautions(1) D o not install in any location of high temperature, high humidity, moisturecondensation and freezing. Do not install the inverter where there are gases thatcorrode metal or solvents that adversely affect plastic.Avoid locations where there is exposure to water and/or where there may be large amountsof dust and metallic fragments. In this case, please install inverters in the enclosure typecabinet. The cabinet must be considered its size and the cooling method to allow thespecifi cations of an ambient temperature for inverters.(2) M ust be installed in non-infl ammables such as metals. The rear panel gets very hot. Ifinstallation is in an infl ammable object, this can result in fi re.(3) I nverters should be arranged in horizontal rows.Wiring precautionsInstalling a molded-case circuit breaker [MCCB](1) I nstall a molded-case circuit breaker (MCCB) on the inverter's power supply input toprotect the wiring.(2) A void turning the molded-case circuit breaker on and off frequently to turn on/off themotor.(3) T o turn on/off the motor frequently, close/break the control terminals F (or R)-CC.Installing a magnetic contactor [MC] [primary side](1) T o prevent an automatic restart after the power interruption or overload relay hastripped, or actuation of the protective circuit, install an electro-magnetic contact in thepower supply.(2) T he inverter is provided with a failure detection relay (FL), so that, if its contacts areconnected to the operation circuit of the magnetic contactor on the primary side,the magnetic contactor will be opened when the protective circuit of the inverter isactivated.(3) T he inverter can be used without a magnetic contactor. In this case, use an MCCB(equipped with a voltage tripping device) for opening the primary circuit when theinverter protective circuit is activated.(4) A void turning the magnetic contactor on and off frequently to turn on/off the motor.(5) T o turn on/off the motor frequently, close/break the control terminals F (or R)-CC.(6) I nstall surge suppressor on any magnetic contactor and relay coils used around theinverter.(7) I f using a braking resistor, install a magnetic contactor (MC) to the power supply ofthe inverter, so that the power circuit opens when the internal overload relay of thebraking resistor is activated.Installing a magnetic contactor [MC] [secondary side](1) A s a rule, if a magnetic contactor is installed between the inverter and the motor, donot turn on/off while running. (If the secondary-side contactor is turned on/off whilerunning, a large current may fl ow in the inverter, causing inverter damage and failure.)(2) A magnetic contactor may be installed to change the motor or change to thecommercial power source when the inverter is stopped. Always use an interlock withthe magnetic contactor in this situation so that the commercial power supply is notapplied to the inverter's output terminals.External signal(1) U se a relay rated for low currents. Mount a surge suppressor on the excitation coil ofthe relay.(2) W hen wiring the control circuit, use shielded wires or twisted pair cables.(3) B ecause all of the control terminals except FLA, FLB ,FLC,RY and RC are connectedto electronic circuits, insulate these terminals to prevent them from coming into contactwith the main circuit.Installing an overload relay(1) T his inverter has an electronic-thermal overload protective function.H owever, in the following cases, the thermal relay operation level must be adjusted oran overload relay matching the motor's characteristics must be installed between theinverter and the motor.(a) W hen using a motor having a rated current value different from that of theequivalent.(b) W hen driving several motors simultaneously.(2) W hen using the inverter to control the operation of a constant-torque motor (VFmotor), change the protective characteristic of the electronic thermal relay accordingto the setting of the VF motor.(3) I n order to adequately protect a motor used for low-speed operation, we recommendthe use of a motor equipped with a embedded thermal relay.Wiring(1) D o not connect input power to the output (motor side) terminals (U/T1,V/T2,W/T3).That will destroy the inverter and may result in fi re. Please pay attentions of wiringbefore power supply turns-on.(2) T he DC terminals (PA/+, PC/-,PBe and PB) are for specifi ed options. Do not connectother devices to these terminals.(3) W ithin 15 minutes after turning off input power, do not touch wires of devices (MCCB)connected to the input side of the inverter.GroundingThe inverters and motors must be connected to ground securely. In case of grounding forinverters, please use the grounding terminal of the inverter.Operating precautions(1) T he inverter operates in abnormal circumstances the security function, and stopsoutputting. However, the inverters can not stop the motors quickly. Please install the[Examples of protective measures]l S eparate the power line from other lines, such as weak-current lines and signal lines,and install them apart from each other.l I nstall a noise reduction fi lter in each inverter. It is effective for noise prevention to installnoise reduction fi lter in other devices and systems, as well.l S hield cables and wires with grounded metallic conduits, and cover electronic systemswith grounded metallic cases.l S eparate the power distribution line of the inverter from that of other devices andsystems.l I nstall the input and output cables of the inverter apart from each other.l U se shielded twisted pair wires for wiring of the weak-current and signal circuits, andalways ground one of each pair of wires.l G round the inverter with grounding wires as large and short as possible, separatelyfrom other devices and systems.All models, noise can be greatly reduced as they have a built-in EMC noisereduction filter on their input side.Power factor improvement capacitorsDo not install a power factor improvement capacitors on the output side of the inverter.Installing a power factor improvement capacitor on the output side causes currentcontaining harmonic components to fl ow into the capacitor, adversely affecting thecapacitor itself or causing the inverter to trip. To improve the power factor, install an inputAC reactor or a DC reactor on the primary side of the inverter.Installation of input AC rectorsThese devices are used to improve the input power factor and suppress high harmoniccurrents and surges. Install an input AC reactor when using this inverter under thefollowing conditions:(1) W hen the power source capacity is 500kVA or more, and when it is 10 times or moregreater than the inverter capacity.(2) W hen the inverter is connected the same power distribution system as athyristor-committed control equipment.(3) W hen the inverter is connected to the same power distribution system as that of distortedwave-producing systems, such as arc furnaces and large-capacity inverters.2. Selecting the Capacity (model) of the InverterSelectionCapacityRefer to the applicable motor capacities listed in the standard specifi cations.When driving a high-pole motor, special motor, or multiple motors in parallel, select suchan inverter that the sum of the motor rated current multiplied by 1.05 to 1.1 is less thanthe inverter's rated output current value.Acceleration/deceleration timesThe actual acceleration and deceleration times of a motor driven by an inverter aredetermined by the torque and moment of inertia of the load, and can be calculated by thefollowing equations.The acceleration and deceleration times of an inverter can be set individually. In anycase, however, they should be set longer than their respective values determined by thefollowing equations.Allowable torque characteristicsWhen a standard motor is combined with an inverter to perform variable speed operation,the motor temperature rises slightly higher than it normally does during commercial powersupply operation. This is because the inverter output voltage has a sinusoidal (approximate)mechanical brake or maintenance function in the mechanical equipment and thedevice for which the emergency stop is necessary.(2) W hen you drive the machine and the device that hangs the load repeatedly with theinverter, the semiconductor within inverter might cause thermal fatigue, and it cometo have a short life if a big current fl ows repeatedly when driving and stopping. In thiscase, it is possible to extend life span by controlling the starting current and the loadcurrent low or setting the PWM career frequency low. If you can not decrease thestarting current, please select larger capacity of inverters for current margins.4. When changing the motor speedApplication to standard motorsVibrationWhen a motor is operated with an inverter, it experiences more vibrations than when it isoperated by the commercial power supply. The vibration can be reduced to a negligiblelevel by securing the motor and machine to the base fi rmly.If the base is weak, however, the vibration may increase at a light load due to resonancewith the mechanical systemAcoustic noiseThe magnetic noise of motors with inverter drives is changed by PWM carrier frequency.In case of high PWM carrier frequency settings, its acoustic noise is almost same ascommercial power supply drives. Moreover, when the motors are operated over ratedrotation, the windy noise of the motors is increased.Reduction gear, belt, chainNote that the lubrication capability of a reducer or a converter used as the interface of themotor and the load machine may affected at low speeds.When operating at a frequencies exceeding 60 Hz or higher, power transmissionmechanisms such as reduction gear, belts and chains, may cause problems such asproduction of noise, a reduction in strength, or shortening of service life.FrequencyBefore setting the maximum frequency to 60 Hz or higher, confi rm that this operatingrange is acceptable for the motor.Starting methodWhen you drive the motor with changeable connection between star-connection anddelta-connection for decreasing starting current, please connect delta-connection only.If you change motor connection while inverter drives, the protective function of inverteroccurs.Application to special motorsGear motorWhen using an inverter to drive a gear motor, inquire of the motor manufacturer about itscontinuous operation range due to the followings:- The low-speed operation of a gear motor may cause insuffi cient lubrication- The loss of a gear may be increasing than commercial power supply drives.- I n case of the high frequency operation, the acoustic noise and motor temperature maybe higher.Toshiba Gold Motor (High-effi ciency power-saving motor)Inverter-driven operation of Toshiba Gold Motors is the best solution for saving energy.This is because these motors have improved effi ciency, power factor, and noise/vibrationreduction characteristics when compared to standard motors.Pole-changing motorPole-changing motors can be driven by this inverter. Before changing poles, however,be sure to let the motor come to a complete stop. If you change motor connection whileinverter drives, the protective function of inverter occurs.Underwater motorsNote that underwater motors have higher rated current than general motorsThe current ratings of underwater motors are relatively high. So, when selecting aninverter, you must pay special attention to its current rating so that the current rating ofthe motor is below that of the inverter.When the lengths of the motor cable are long, please use thicker cable than a table of‘Wiring devices’ because the maximum torque is decreased by the voltage dropping..Moreover, please pay attention to select leakage circuit breakers.Single-phase motorBecause single-phase motors are equipped with a centrifugal switch and capacitorsfor starting, they cannot be driven by an inverter. When single phase motors are drivenby inverters, a centrifugal switch and capacitors may be broken. If only a single-phase,power system is available a 3-phase motor can be driven by using a single-phase inputinverter to convert it into a 3-phase 200V output. (A special inverter and a 3-phase 200Vmotor are required.)Braking motorWhen using a braking motor, if the braking circuit is directly connected to the inverter'soutput terminals, the brake cannot be released because of the lowered starting voltage.Therefore, when using a braking motor, connect the braking circuit to the inverter's powersupply side, as shown on the below. Usually, braking motors produce larger noise in lowspeed ranges.For inverter users1819。
三相电机矢量控制的设计 《英文》
The Design of the Vector Control System of Asynchronous MotorMin Zhang, Xinping Ding & Zhen GuoCollege of Automation, Qingdao Technological University, Qingdao 266033, ChinaE-mail: z_m530@AbstractAmong various modes of the asynchronous motor speed control, vector control has the advantages of fast response, stability, transmission of high-performance and wide speed range. For the need of the asynchronous motor speed control, the design uses 89C196 as the controller, and introduces the designs of hardware and software in details. The Design is completed effectively, with good performance simple structure and good prospects of development.Keywords: Asynchronous motor, 89C196, Vector control 1. IntroductionAC asynchronous motor is a higher order, multi-variable, non-linear, and strong coupling object, using the concept of parameters reconstruction and state reconstruction of modern control theory to achieve decoupling between the excitation component of the AC motor stator current and the torque component, and the control process of AC motor is equivalent to the control process of DC motor, the dynamic performance of AC speed regulation system obtaining notable improvement, thus makes DC speed replacing AC speed possible finally. The current governor of the higher production process has been more use of Frequency Control devices with vector-control. 2. Vector ControlWith the criterion of producing consistent rotating magnetomotive force,the stator AC current A i ,B i ,C i by3S/2S conversion in the three-phase coordinate system, can be equivalent to AC current s d i ,sqi in two-phase static coordinate system, through vector rotation transformation of the re-orientation of the rotor magnetic field,Equivalent to a synchronous rotation coordinates of the DC current ed i ,e q i . When observers at core coordinates with the rotation together, AC machine becomes DC machine. Of these, the AC induction motor rotor total flux r Ψ, it has become the equivalent of the DC motor flux, windings e d equivalent to the excitation windings ofDC motor , ed i equivalent to the excitation current, windings e q equivalent to false static windings, e q iequivalent to the armature current proportional to torque. After the transformation above, AC asynchronous motor has been equivalent to DC motor. As a result, imitating the control method of DC motor, obtaining the control variable of DC motor, through the corresponding coordinates anti-transformation, can control the asynchronous motor. As a result of coordinate transformation of the current (on behalf of magnetic momentum) space vector, thus, this control system achieved through coordinate transformation called the vector control system, referred to VC system. According to this idea, could constitute the vector control system that can controlr Ψand eq i directly, as shown in Figure 1. In the figure a given and feedback signal through the controllersimilar to the controller that DC speed control system has used, producing given signal *e qs i of the excitation current and given signal *e ds i of the armature current, after the anti-rotation transform 1VR − obtaining *s ds iand *s qs i , obtains *A i ,*B i ,*C i by 3S/2S conversion. Adding the three signals controlled by current and frequencysignal 1ω obtained by controller to the inverter controlled by current, can output three-phase frequencyconversion current that asynchronous motor needs for speed. 3. The Content and Thought of the DesignThis system uses 80C196 as controller, consists of detection unit of stator three-phase current unit of keyboard input, LCD display modules, given unit of simulation speed detection unit of stator three-phase voltage, feedback unit of speed and output unit of control signals. System block diagram shown in Figure 2, the system applies 16 bits MCU 80C196 as control core, with some hardware analog circuits composing the vector control system of asynchronous motor. On the one hand, 80C196 through the A/D module of 80C196, speed gun and the given speed feedback signals has been obtained, obtaining given torque of saturated limiting through speed regulator, to obtain the given torque current; Use a given function generator to obtain given rotor flux, through observation obtaining real flux, through flux regulation obtaining given excitation current of given stator current,then the excitation current and the torque current synthesis through the K/P transformation, obtaining amplitude and phase stator current, after amplitude of stator current compared to the testing current , control the size of stator current through current regulator.; on the other hand, the stator current frequency is calculated by the simultaneous conversion rate for the time constant of the control inverter, regularly with timer, through P1, submitting trigger word to complete the trigger of the inverter. 4. The Design of Hardware and SoftwareThe hardware circuits of the system mainly consists of AC-DC-AC current inverter circuit, SCR trigger inverter circuit, rectifier SCR trigger circuit, the speed given with the gun feedback circuit, current central regulation circuit, protection circuit and other typical circuits. The design of software includes: speed regulator control and flux detection and regulation.4.1 AC-DC-AC Current Converter CircuitThe main circuit uses AC-DC-AC Current Converter in the system as shown in Figure 3, and main features can be known as follows:1) Main circuit with simple structure and fewer components. For the four-quadrant operation, when the brake of power happens, the current direction of the main circuit keeps the same, just changing the polarity of the voltage, rectifier working in the state of inverter, inverter working in the state of rectifier. The inverter can be easily entered, regenerative braking, fast dynamic response. The voltage inverter has to connect to a group of inverters in order to regenerative braking, bringing the electric energy back to power grids.2) Since the middle using a reactor, current limit, is constant current source. Coupled with current Loop conditioning, current limit, so it can tolerate instantaneous load short-circuit, automatic protection, thereby enhancing the protection of over current and operational reliability3) The current inverter can converter with force, and the output current instantaneous value is controlled by current inverter, meeting the vector control requirements of AC motors. Converter capacitor charging and discharging currents from the DC circuit filter by the suppression reactor, unlike a greater inrush current in voltage inverter, the capacitor’s utilization is of high level.4) Current inverter and the load motor form a whole, and the energy storage of the motor windings is also involved in the converter, and less dependent on the voltage inverter, so it has a certain load capacity. 4.2 Inverter SCR trigger drive circuitThe Inverter SCR trigger drive circuit as shown in Figure 4. Inverter trigger signal is controlled by P1 of 80C196, slip signal outputting through P1 via PWM regulation in the SCM through the photoelectric isolation to enlarge, to control the trigger of the inverter. The system uses P1.6 as control and uses P1.0~P1.5 to control six SCR inverters separately, so the trigger circuits is composed by six circuits above.The principles of drive circuit of SCR trigger inverter are as follows: when the PWM from P1 is high signal after and gate, photoelectric isolation is not on, composite pipe in a state of on-saturated, the left side of the transformer forming circuit, and that the power of the signal amplifies (current enlarges); when the PWM from P1 is low signal after and gate, photoelectric isolation is on, composite pipe in a state of cut-off, and the left side of the transformer can not form circuit; thus, composite pipe equivalent to a switch, and its frequency relied on the frequency of the PWM, so the left side of the transformer form AC signals, to trigger SCR inverter after transformer decompression, half-wave rectifier and filter. 4.3 Current Loop conditioning circuitsAfter the vector calculation, outputting given current through D/A module, testing feedback current by the current testing circuit, sending them to the simulator of the P1 regulator to regulate, can eliminate static difference and improve the speed of regulation. The output of the analog devices can be regarded as the phase-shifting control signals of the rectifier trigger. Current Loop conditioning circuits as shown in figure 5. 4.4 The control of speed regulatorSpeed regulator uses dual-mode control. Setting a value T N of speed error, when the system is more than the deviation (more than 10 percent of the rated frequency), as rough location of the start, using on-off control, at this time, speed regulator is in the state of amplitude limit,equivalent to speed loop being open-loop, so the current loop is in the state of the most constant current regulation. Thus, it can play the overload ability of motor fully and make the process of regulation fastest possibly. When the system enters into a state of small deviation, the system uses PI linear control instead of on-off control. As result, absorbing the benefits of non-linear andlinear, the system meets stability and accuracy. The speed regulator flowchart is as shown in figure 6. 4.5 Flux RegulationSlip frequency vector control system can be affected by the motor parameters, so that the actual flux and the given flux appear a deviation. This system is of observation and feedback in the amplitude of the magnetic flux, regulating flux of the rotor, actual flux with the changes of given flux.Flux regulator is also the same as the speed regulator, using PI regulator. The discrete formula is:()(1){()()/m m m i s i n i n i n k e n T e n t =−+Δ+ (1)Plus a reminder to forecast for correction:2()(1)m m m I i n i n =−− (2)In the formula, m k is proportional coefficient, n t is integral coefficient, s T is sampling period, m I is the actual output value.()(1)n e e n e n Δ=−− (3) *22()()n e n n =Φ−Φ (4)When it is in the state of low frequency (f<5HZ), 1r can not be ignored, the phase difference between 1V and1E enlarges, and the formula '11V V ≈ no longer sets up. Through the Approximate rotor flux observer and theformula 2111011()/m m T m I L V I r I L ωΦ==−− to observe the flux amplitude, only open-loop control of flux, that is, to calculate from a given flux, and that is *2/m m I L =Φ.In addition, in order to avoid disorders, or too weak and too strong magnetic, limiting the output m i inpreparation for the software, making it in the ranges from 75% to 115% rated value. 5. Design SummaryThis text researches the vector control variable speed control system of the asynchronous motor design. The SCM 80 C196 and the external hardware complete the asynchronous motor speed vector control system design efficiently, and meet the timing control requirements. The vector control system design thinks clearly, has a good speed performance and simple structure. It has a wide range of use and a good prospect of development from the analysis and design of the speed asynchronous motor vector control systems. The innovations:(1) Complete the data acquisition of the speed and voltage, output the control signal and save the devices effectively with the help of the 80C196 microcontroller owned A/D, D/A.(2) Because the Current Source Inverter uses forced converter, the maximum operating frequency is free from the power grid frequency. And it is with wide speed range.(3) This system uses constant flux to keep the constant flux stably. Use stator physical voltage amplitude to approximate the observed flux amplitude value. The magnetic flux overcomes the impact of the parameters changes. This way is simple and effective. ReferencesHisao Kubota and Kouki Matsuse. (1994). Speed Sensorless Field-Oriented Control of Induction Motor with Rotor Resistance Adaptation. IEEE Trans. Ind. Appl., vo1.30, No.5,pp.1219-1224.Li, Da, Yang, Qingdong, and Liu, Quan.(2007). The DSP permanent magnet synchronous linear motor vector control system. Micro-computer information , 09-2:195-196Liu, Wei. (2007). The application design about vector control of current loop control. Micro-computer information , 07-1: 68-70Zhao,Tao, Jiang, WeiDong, Chen, Quan, and Ren, Tao. (2006). The research about the permanent magnet motor drive system bases on the dual-mode control. Power electronics technology , 40 (5) :32-34Figure 2. Scheme of systemFigure 6. Flux regulation flowchart。
新能源汽车专业英语试题库答案最新完整精品
2020版《新能源汽车专业英语》试题库第一部分：专业术语第二部分：常用缩写第三部分：英译汉1. What are Alternative fuels currently commercially available and closely attended? 目前商业可用和受到密切关注的替代燃料有哪些？· Liquefied petroleum gas 液化石油气· CNG 压缩天然气· Methanol 甲醇· Hydrogen 氢· Fuel-cell 燃料电池· Electricity 电能· Hybrid（electricity + conventional fuels）混合动力（电+传统燃料）2. What are the types of electric vehicles? 电动汽车分为哪几种？Electric vehicles are broadly categorized into four groups based on the electric design of their powertrains, namely battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and fuel-cell electric vehicles (FCEVs). Only BEVs and PHEVs are plug-capable, and are referred to as plug-in electric vehicles (PEVs).根据电动汽车动力传动系统的电动设计，将电动汽车大致分为四大类，即纯电动汽车(BEV)、插电式混合动力汽车(PHEV)、混合动力电动汽车(HEV)和燃料电池电动汽车(FCEV)。
感应电机induction+motors
1500 (转/分）
1000 (转/分）
Rotor speed and magnetic field speed
电动机转速（额定转速）:
n
电机转子转动方向与磁场旋转的方向一致， 但
n < n1
异步电动机
提示：如果
n = n1
转子与旋转磁场间没有相对运动 无转子电动势（转子导体不切割磁力线） 无转子电流 无转矩
5. Fractional Slip
⎛ n1 − n ⎞ ⎟ × 100 % s=⎜ ⎟ ⎜ n 1 ⎠ ⎝
At the beginning of start:
n = 0,
The range of slip:
s =1
0 ≤ s <1
(maximum slip)
Usually
s = 1 ~ 9%
关于相对转速
2. Torque-speed Characteristic
n1 − n s = n1
sR2 2 T=K 2 × U1 2 R2 + ( sX 20 )
n
n1
T
T = f (S )
n = f (T )
s
0 1
T
3. Important Torques Rated torque TN
nN
n1
n
T
额定功率
Example An induction machine p=3，the frequency of the source f1=50Hz，the rated speed of the motor n=960r/min. Find: fractional speed s, the frequency of rotor current f2 Solution
上海大学沈天飞教授专业英语上课练习答案
1 Intelligent flight controllers for helicopter control1)A methodology for design of an intelligent helicopter flight controller is presented in this paper. 2)The methodology combines artificial neural network, genetic algorithms, conventional PID-controllers, and fuzzy logic algorithms in the design procedure.3) In this approach, the design of an intelligent controller is based on experimental data collected from actual helicopter flight and not based on analytical models.4)A neural network is trained to learn the dynamic characteristics of the helicopter. 5)Based on the neural model, the coefficients of a PID-controller used for blade angle control are searched for using genetic algorithms. 6)The main rotor speed controller is designed using fuzzy logic algorithm based on knowledge generated from understanding the aerodynamic theory and analyzing the helicopter experimental flight data. 7)The intelligent helicopter flight controller is formed by combining the blade angle PID-controller and the rotor speed fuzzy controller. 8)Simulation results showed that for desired altitude input H d, the intelligent controller was able to generate proper control signals for both the blade angle control and the rotor speed control. 9）The helicopter model altitude output H t follows the desired altitude input H d. 10）The design procedures, theoretical background, results and conclusions are presented in this paper2. EDFA gain modeling using Pspice and neural networks1）A new methodology in modeling the performance of an Erbium Doped Fiber Amplifier (EDFA) Gain is presented in this dissertation. 2）It is based on the gain characteristics of an EDFA under different input signal power spectra and pump levels. 3）The novelty of this dissertation is based on the training and use of a neural network applied to the performance characteristics of an EDFA.;The modeling is divided in two sections. 4）The first model is an electrical equivalent circuit of an EDFA that can be simulated and analyzed by Pspice, a commercial electrical simulation program from OrCad. 5）The second section is the development and implementation of a Neural Network to model the gain response of the EDFA for a given number of input power spectra.;6）In order to provide data and verify the performance of both models, a simulation program was developed. 7）The simulation program's output performance was verified using an EDFA analysis program called Oasix.;8）The results from both models were accurate with respect to the theoretical and experimental data. 9）The electrical equivalent model's output spectrum was proven to match the output of the simulation program. 10）The neural network was trained successfully to identify the EDFA gain spectra to its correspondent input spectrum and pump power level with an accuracy of 98%.4、Characterization and Modeling of the Power Insulated Gate Bipolar Transistor.The power Insulated Gate Bipolar Transistor (IGBT) is a new switching device designed to overcome the high on-state loss of the power MOSFET. The IGBT behaves as a bipolar transistor which is supplied base current by a MOSFET. The bipolar transistor of the IGBT has a wide base with the base contact at the collector edge of the base and is operated with its base in high-level injection. Because of this, the traditional bipolar transistor models are not adequate for the IGBT and the new model developed in this dissertation must be used. The new model is developedusing ambipolar transport and does not assume the quasi-static condition for the transient analysis.;The new IGBT model is used to describe measurements for extracting the essential physical device parameters of the model. With these extracted parameters, the new IGBT model consistently describes the measured electrical characteristics of IGBTs with different base lifetimes. The important electrical characteristics of the IGBT are the on-state I-V characteristics, the steady-state saturation current, and the switching transient current and voltage waveforms. The transient waveforms are examined in detail for constant anode voltage switching, clamped inductive load switching, and series resistor, inductor load switching.;The disadvantage of the IGBT is its slow turn-off speed relative to that of the power MOSFET. The two methods which have been proposed to reduce the turn-off time of the IGBT are base lifetime reduction and buffer layer inclusion. Both methods have the disadvantage, though, of also increasing the on-state voltage. The buffer layer is a high-doped portion of the bipolar transistor base at the base-emitter junction. The new IGBT model discussed above is extended to include the buffer layer. Using the extended model, it is shown that the buffer layer IGBT can be made to have a faster switching time for a given on-state voltage than that of the nonbuffer layer (lifetime reduction) IGBT.;In summary, a new model is developed for the IGBT. It is shown that the new model must be used to accurately describe the steady-state and transient characteristics of the IGBT. The model is used to compare the effects of lifetime reduction and buffer layer inclusion. The results of the comparison show that a better on-state voltage, switching speed trade-off is obtained using the buffer layer than is obtained using lifetime reduction.5、Developing modeling and simulation methodology for virtual prototype power supply systemThis dissertation develops a modeling and simulation methodology for design, verification, and testing (DVT) power supply system using a virtual prototype. The virtual prototype is implemented before the hardware prototyping to detect most of the design errors and circuit deficiencies that occur in the later stage of a standard hardware design verification and testing procedure. The design iterations and product cost are reduced significantly by using this approach. ^ The proposed modeling and simulation methodology consists of four major parts: system partitioning, multi-level modeling of device/function block, hierarchical test sequence, and multi-level simulation. By applying the proposed methodology, the designer can use the virtual prototype effectively by keeping a short simulation CPU time as well as catching most of the design problems. ^ The proposed virtual prototype DVT procedure is demonstrated by simulating a 5 V power supply system with a main power supply, a bias power supply, and other protection, monitoring circuitry. The total CPU time is about 8 hours for 780 tests that include the basic function test, steady stage analysis, small-signal stability analysis, large-signal transient analysis, subsystem interaction test, and system interaction test. By comparing the simulation results with the measurements, it shows that the virtual prototype can represent the important behavior of the power supply system accurately. Since the proposed virtual prototype DVT procedure verifies the circuit design with different types of the tests over different line and load conditions, many circuit problems that are not obvious in the original circuit design can be detected by the simulation. ^ The developed virtual prototype DVT procedure is not only capable of detecting most of the design errors, but also plays an important role in design modifications. This dissertation also demonstrates how to analyze the anomalies of the forward converter with active-clamp reset circuit extensively and facilitate the design and improve the circuitperformances by utilizing the virtual prototype. With the help of the virtual prototype, it is the first time that the designer is able to analyze the dynamic behavior of the active-clamp forward converter during large-signal transient and optimize the design correspondingly.7、Adaptive nonlinear control of spacecraftThe problem of spacecraft attitude control and momentum management is addressed using nonlinear controllers based on feedback linearization. A chief limitation of the feedback linearization technique is that it requires an exact cancellation of nonlinear terms in order to obtain linear input-output behavior. Adaptive nonlinear controllers for linearizable systems are investigated to overcome this restriction and to achieve asymptotic linear behavior. The spacecraft attitude control and momentum mangement model is characterized by having uncertain parameters appearing linearly on both sides of the dynamicl equation. Therefore，two adaptive controf laws are developed forgeneral models in which the parameters appear linearly on both sides of the dynamical equations.The spacecraft attitude control and momentum mangement problem is then addressed with the adaptive nonlineu control laws utilized and uncertainties in the spacecraft principal intertias assumed. The adaptive nonlinear approach is shown to effectively control the Space Station attitude and effector momentum, while providing accurate estimates of inertias. The combined tracking prediction-error based tracking is shown to have improvement over the performance of the tracking-error based adaptive controller.8、Discrete-Time Control of A Spacecraft with Retargetable Flexible Antennas.This dissertation considers the discrete-time control of a spacecraft consisting of a rigid-platform. with retargetable flexible antennas. The mission consists of independent minimum-time maneuvers of each antenna to coincide with predetermined lines of sight, while the platform. is stabilized in an inertial space and elastic vibration of the antennas is suppressed. The system is governed by a set of linearized, time-varying equations of motion. A discrete-time approach permits consideration of the time-varying nature of the system in designing the control law.;Both global and decentralized controls are proposed for a noise-free system with full-state feedback. Initially, a time-varying linear-quadratic regulator (LQR) is implemented, followed by two types of decentralized controllers. First, a collocated control law is devised in which actuator forces are based on the position and velocity at the actuator locations. Next, a new method called Substructure-Decentralized Control is proposed, where each flexible substructure is controlled based on state measurements associated with the substructure modes of the separately modeled appendages.;In both global and decentralized cases, a linear control law is first implemented coupled with an open-loop disturbance-accommodating control based on the known inertial disturbances caused by the maneuver. Elastic motion is next controlled using nonlinear (on-off) antenna controllers for each decentralized case. For Substructure-Decentralized Control, the controls translate into quantized actual controls. Lastly, nonlinear (on-off) control laws are also used to control the rigid-body motion for each case.;Next, the problem of controlling the time-varying system in the presence of noisy actuators and sensors is examined. It is assumed that only displacements, not velocities, are sensed for both rigid-body and elastic motion, making state reconstruction also necessary. A discrete-time, full-order Kalman filter is constructed for the time-varying system. A pseudo-decentralized control is proposed whereby feedback controls are based on system state estimates. As before, both linear and nonlinear controls are implemented. For each case mentioned, a numerical example is presented involving a spacecraft with a singleflexible maneuvering antenna.。
异步电动机起动中英文对照外文翻译文献
中英文对照外文翻译中英文对照外文翻译英文资料：INDUCTION MOTOR STARTING METHODSAbstract -Many methods can be used to start large AC induction motors. Choices such as full voltage, reduced voltage either by autotransformer or Wyes - Delta, a soft starter, or usage of an adjustable speed drive can all have potential advantages and trade offs. Reduced voltage starting can lower the starting torque and help prevent damage to the load. Additionally, power factor correction capacitors can be used to reduce the current, but care must be taken to size them properly. Usage of the wrong capacitors can lead to significant damage. Choosing the proper starting method for a motor will include an analysis of the power system as well as the starting load to ensure that the motor is designed to deliver the needed performance while minimizing its cost. This paper will examine the most common starting methods and their recommended applications.I. INTRODUCTIONThere are several general methods of starting induction motors: full voltage, reduced voltage, wyes-delta, and part winding types. The reduced voltage type can include solid state starters, adjustable frequency drives, and autotransformers. These, along with the full voltage, or across the line starting, give the purchaser a large variety of automotives when it comes to specifying the motor to be used in a given application. Each method has its own benefits, as well as performance trade offs. Proper selection will involve a thorough investigation of any power system constraints, the load to be accelerated and the overall cost of the equipment.In order for the load to be accelerated, the motor must generate greater torque than the load requirement. In general there are three points of interest on the motor's speed-torque curve. The first is locked-rotor torque (LRT) which is the minimumtorque which the motor will develop at rest for all angular positions of the rotor. The second is pull-up torque (PUT) which is defined as the minimum torque developed by the motor during the period of acceleration from rest to the speed at which breakdown torque occurs. The last is the breakdown torque (BDT) which is defined as the maximum torque which the motor will develop. If any of these points are below the required load curve, then the motor will not start.The time it takes for the motor to accelerate the load is dependent on the inertia of the load and the margin between the torque of the motor and the load curve, sometimes called accelerating torque. In general, the longer the time it takes for the motor to accelerate the load, the more heat that will be generated in the rotor bars, shorting ring and the stator winding. This heat leads to additional stresses in these parts and can have an impaction motor life.II. FULL VOLTAGEThe full voltage starting method, also known as across the line starting, is the easiest method to employ, has the lowest equipment costs, and is the most reliable. This method utilizes a control to close a contactor and apply full line voltage to the motor terminals. This method will allow the motor to generate its highest starting torque and provide the shortest acceleration times.This method also puts the highest strain on the power system due to the high starting currents that can be typically six to seven times the normal full load current of the motor. If the motor is on a weak power system, the sudden high power draw can cause a temporary voltage drop, not only at the motor terminals, but the entire power bus feeding the starting motor. This voltage drop will cause a drop in the starting torque of the motor, and a drop in the torque of any other motor running on the power bus. The torque developed by an induction motor varies roughly as the square of the applied voltage. Therefore, depending on the amount of voltage drop, motors running on this weak power bus could stall. In addition, many control systems monitor under voltage conditions, a second potential problem that could take a running motor offline during a full voltage start. Besides electrical variation of the power bus, a potential physical disadvantage of an across the line starting is the sudden loading seen by the driven equipment. This shock loading due to transient torques which can exceed 600% of the locked rotor torque can increase the wear on the equipment, or even cause a catastrophic failure if the load can not handle the torques generated by themotor during staring.A. Capacitors and StartingInduction motors typically have very low power factor during starting and as a result have very large reactive power draw. See Fig. 2. This effect on the system can be reduced by adding capacitors to the motor during starting.The large reactive currents required by the motor lag the applied voltage by 90 electrical degrees. This reactive power doesn't create any measurable output, but is rather the energy required for the motor to function. The product of the applied system voltage and this reactive power component can be measured in V ARS (volt-ampere reactive). The capacitors act to supply a current that leads the applied voltage by 90 electrical degrees. The leading currents supplied by the capacitors cancel the lagging current demanded by the motor, reducing the amount of reactive power required to be drawn from the power system.To avoid over voltage and motor damage, great care should be used to make sure that the capacitors are removed as the motor reaches rated speed, or in the event of a loss of power so that the motor will not go into a generator mode with the magnetizing currents provided from the capacitors. This will be expanded on in the next section and in the appendix.B. Power Factor CorrectionCapacitors can also be left permanently connected to raise the full load power factor. When used in this manner they are called power factor correction capacitors. The capacitors should never be sized larger than the magnetizing current of the motor unless they can be disconnected from the motor in the event of a power loss.The addition of capacitors will change the effective open circuit time constant of the motor. The time constant indicates the time required for remaining voltage in the motor to decay to 36.8% of rated voltage after the loss of power. This is typically one to three seconds without capacitors.With capacitors connected to the leads of the motor, the capacitors can continue to supply magnetizing current after the power to the motor has been disconnected. This is indicated by a longer time constant for the system. If the motor is driving a high inertia load, the motor can change over to generator action with the magnetizingCurrent from the capacitors and the shaft driven by the load. This can result in the voltage at the motor terminals actually rising to nearly 50% of rated voltage in some cases. If the power is reconnected before this voltage decays severe transients can be created which can cause significant switching currents and torques that can severely damage the motor and the driven equipment. An example of this phenomenon is outlined in the appendix.Ⅲ. REDUCED VOLTAGEEach of the reduced voltage methods are intended to reduce the impact of motor starting current on the power system by controlling the voltage that the motor sees at the terminals. It is very important to know the characteristics of the load to be started when considering any form of reduced voltage starting. The motor manufacturer will need to have the speed torque curve and the inertia of the driven equipment when they validate their design. The curve can be built from an initial, or break away torque, as few as four other data points through the speed range, and the full speed torque for the starting condition. A centrifugal or square curve can be assumed in many cases, but there are some applications where this would be problematic. An example would be screw compressors which have a much higher torque requirement at lower speeds than the more common centrifugal or fan load. See Fig. 3. By understanding the details of the load to be started the manufacturer can make sure that the motor will be able to generate sufficient torque to start the load, with the starting method that is chosen.A. AutotransformerThe motor leads are connected to the lower voltage side of the transformer. The most common taps that are used are 80%, 65%, and 50%. At 50% voltage the current on the primary is 25% of the full voltage locked rotor amps. The motor is started with this reduced voltage, and then after a pre-set condition is reached the connection is switched to line voltage. This condition could be a preset time, current level, bus volts, or motor speed. The change over can be done in either a closed circuit transition, or an open circuit transition method. In the open circuit method the connection to the voltage is severed as it is changed from the reduced voltage to the line level. Care should be used to make sure that there will not be problems from transients due to the switching. This potential problem can be eliminated by using the closed circuit transition. With the closed circuit method there is a continuousVoltage applied to the motor. Another benefit with the autotransformer starting is in possible lower vibration and noise levels during starting.Since the torque generated by the motor will vary as the square of the applied voltage, great care should be taken to make sure that there will be sufficient accelerating torque available from the motor. A speed torque curve for the driven equipment along with the inertia should be used to verify the design of the motor. A good rule of thumb is to have a minimum of 10% of the rated full load torque of the motor as a margin at all points of the curve.Additionally, the acceleration time should be evaluated to make sure that the motor has sufficient thermal capacity to handle the heat generated due to the longer acceleration time.B. Solid State or Soft StartingThese devices utilize silicon controlled rectifiers or Scars. By controlling the firing angle of the SCR the voltage that the device produces can be controlled during the starting of the motor by limiting the flow of power for only part of the duration of the sine wave.The most widely used type of soft starter is the current limiting type. A current limit of 175% to 500% of full load current is programmed in to the device. It then will ramp up the voltage applied to the motor until it reaches the limit value, and will then hold that current as the motor accelerates.Tachometers can be used with solid state starters to control acceleration time. Voltage output is adjusted as required by the starter controller to provide a constant rate of acceleration.The same precautions in regards to starting torque should be followed for the soft starters as with the other reduced voltage starting methods. Another problem due to the firing angle of the SCR is that the motor could experience harmonic oscillating torques. Depending on the driven equipment, this could lead to exciting the natural frequency of the system.C. Adjustable Frequency DrivesThis type of device gives the greatest overall control and flexibility in startinginduction motors giving the most torque for an amount of current. It is also the most costly.The drive varies not only the voltage level, but also the frequency, to allow the motor to operate on a constant volt per hertz level. This allows the motor to generate full load torque throughout a large speed range, up to 10:1. During starting, 150% of rated current is typical.This allows a significant reduction in the power required to start a load and reduces the heat generated in the motor, all of which add up to greater efficiency. Usage of the AFD also can allow a smaller motor to be applied due to the significant increase of torque available lower in the speed range. The motor should still be sized larger than the required horsepower of the load to be driven. The AFD allows a great degree of control in the acceleration of the load that is not as readily available with the other types of reduced voltage starting methods.The greatest drawback of the AFD is in the cost relative to the other methods. Drives are the most costly to employ and may also require specific motor designs to be used. Based on the output signal of the drive, filtered or unfiltered, the motor could require additional construction features. These construction features include insulated bearings, shaft grounding brushes, and insulated couplings due to potential shaft current from common mode voltage. Without these features, shaft currents, which circulate through the shaft to the bearing, through the motor frame and back, create arcing in the bearings that lead to premature bearing failure, this potential for arcing needs to be considered when applying a motor/drive package in a hazardous environment, Division2/Zone2.An additional construction feature of a motor used on an AFD may require is an upgraded insulation system on the motor windings. An unfiltered output signal from a drive can create harmonic voltage spikes in the motor, stressing the insulation of the motor windings.It is important to note that the features described pertain to motors which will be started and run on an AFD. If the drive is only used for starting the motor, these features may not be necessary. Consult with the motor manufacturer for application specific requirements.D. Primary Resistor or Reactor StartingThis method uses either a series resistor or reactor bank to be placed in the circuit with the motor. Resistor starting is more frequently used for smaller motors.When the motor is started, the resistor bank limits the flow of inrush current and provides for a voltage drop at the motor terminals. The resistors can be selected to provide voltage reductions up to 50%. As the motor comes up to speed, it develops a counter EMF (electro-magnetic field) that opposes the voltage applied to the motor. This further limits the inrush currents. As the inrush current diminishes, so does t>e voltage drop across the resistor bank allowing the torque generated by the motor to increase. At a predetermined time a device will short across the resistors and open the starting contactor effectively removing the resistor bank from the circuit. This provides for a closed transition and eliminates the concerns due to switching transients.Reactors will tend to oppose any sudden changes in current and therefore act to limit the current during starting. They will remain shorted after starting and provide a closed transition to line voltage.E .Star delta StartingThis approach started with the induction motor, the structure of each phase of the terminal are placed in the motor terminal box. This allows the motor star connection in the initial startup, and then re-connected into a triangle run. The initial start time when the voltage is reduced to the original star connection, the starting current and starting torque by 2 / 3. Depending on the application, the motor switch to the triangle in the rotational speed of between 50% and the maximum speed. Must be noted that the same problems, including the previously mentioned switch method, if the open circuit method, the transition may be a transient problem. This method is often used in less than 600V motor, the rated voltage 2.3kV and higher are not suitable for star delta motor start method.Ⅴ. INCREMENT TYPEThe first starting types that we have discussed have deal with the way the energy is applied to the motor. The next type deals with different ways the motor can be physically changed to deal with starting issues.Part WindingWith this method the stator of the motor is designed in such a way that it is made up of two separate windings. The most common method is known as the half winding method. As the name suggests, the stator is made up of two identical balanced windings. A special starter is configured so that full voltage can be applied to one half of the winding, and then after a short delay, to the second half. This method can reduce the starting current by 50 to 60%, but also the starting torque. One drawback to this method is that the motor heating on the first step of the operation is greater than that normally encountered on across-the-line start. Therefore the elapsed time on the first step of the part winding start should be minimized. This method also increases the magnetic noise of the motor during the first step.IV .ConclusionThere are many ways asynchronous motor starting, according to the constraints of power systems, equipment costs, load the boot device to select the best method. From the device point of view, was the first full-pressure launch the cheapest way, but it may increase the cost efficiency in the use of, or the power supply system in the region can not meet their needs. Effective way to alleviate the buck starts the power supply system, but at the expense of the cost of starting torque.These methods may also lead to increased motor sizes have led to produce the required load torque. Inverter can be eliminated by the above two shortcomings, but requires an additional increase in equipment costs. Understand the limitations of the application, and drives the starting torque and speed, allowing you for your application to determine the best overall configuration.英文资料翻译：异步电动机起动的方法摘要：大容量的交流异步电动机有多种启动方法。
883013a_VectorControlOfAcInductionMotors
Principles of Vector Control (cont’d)
The motor phase currents, ia, ib and ic are converted to idss and iqss in the stationary reference frame. These are then converted to the synchronously rotating reference frame d-q currents, ids and iqs. In the controller two inverse transforms are performed: 1) From the synchronous d-q to the stationary d-q reference frame; 2) From d*-q* to a*, b*, c*.
ECE 8830 - Electric Drives
Topic 13: Vector Control of AC Induction Motors
Spring 2004
Introduction
Scalar control of ac drives produces good steady state performance but poor dynamic response. This manifests itself in the deviation of air gap flux linkages from their set values. This variation occurs in both magnitude and phase. Vector control (or field oriented control) offers more precise control of ac motors compared to scalar control. They are therefore used in high performance drives where oscillations in air gap flux linkages are intolerable, e.g. robotic actuators, centrifuges, servos, etc.
东洋电机制造的工业系统与电气设备说明书
Our Heart and Technology for the Future Industrial System & Electrical EquipmentFor a new age in manufacturingThe power of products that create valueIndustrial System & Electrical Providing customers with technology and inspiration withour high-precision, high-response, high-efficiency power electronics, envisioning the path to an environmentally friendly societyToyo Denki Seizo serves customers across Japan and around the world through its generalindustrial machinery and equipment, automobile development testers, and social infrastructurethat is essential to daily life. In addition, we offer energy-saving motors and inverters,as well as products based on advanced system architecture technology thatmakes extensive use of FA controllers and networks. We also ensure that ourmanufacturing practices contribute to the fight against climate change.Industrial SystemSocial Infrastructure System EnvironmentalResponseDrive System ………………………3 - 4Automotive Testing System ……5 - 6Social Infrastructure System ……7 - 8Toyo Network System (TNS) …9 - 10μGPCsH/μGPCdsP ……………11 - 12Inverter Lineup (13)VF66B (14)VF66B DC drive mode (15)VF66C (16)VF66SV (17)VF66AD/VF66PD (18)VF66CH/CH66 (19)VF66R (20)VF66G .......................................21Motor Lineup (23)ED Motor (24)UF Motor (25)Direct Drive Motor ……………………26Low-Inertia Motor ……………………27Renewable energy ……………………28Power Generating Equipment ……29Tandem Generating Equipment/High-Speed Power Switching Equipment …30Steam turbine generator ……………31Energy Storage System for railway …32Total Support ……………………33-34Index EquipmentDrive SystemProviding manufacturing solutions around the world in response to including needs for high quality and high functionalityWe use our vast, wide-ranging technologies and products to provide our customerswith optimal control systems. We harness the power of Toyo Network System (TNS),which uses our VF66B series inverters and the high-speed, advanced-function controllerμGPCsH, to deliver high-precision, high-response systems, including those for theintegrated management of production data.Intelligent inverterPermanent magnet synchronous motorInduction motor for inverter High-speed, advanced-function FA controllerdiverse needs,Regenerative converterPLC-type DSP controller4Automotive Testing System Supporting the development of next-generation automobiles byshortening development time through high precision and high reliaWe developed low-inertia motors equivalent to a car engine that reduced the required motor inertia toone-tenth the previous value. These engine simulators were made possible through a variety of weight-saving technologies. We have also enabled the dynamic testing of automotive parts by combining high-Sample screen for HMI monitor featuresSimulation bench systembilityTest equipment for automobiles, motorcycles, and construction equipment • Transmission testing equipment• Other productsProduct examplesBank FactoryCity hallDrinking water treatment plant E³ Solution SystemHospital Data centerSocial Infrastructure System Contributing to public services that support people’s lives around the Electric power is one of the most important types of social infrastructure and crucial to daily life. Our power generation systems for everyday and emergency use supply safe and stable electric power. We propose the best possible solutions to our customers, always taking the environment and energy conservation in consideration. Our power generating equipment, steam turbine generating equipment, cogeneration systems, and other technologies are thekey to unlocking natural and sustainable energy, such as wind energy and hydroelectric energy.Tidal power generationHydroelectric power generation School Outlying islandWind power generation Wave power generationOur distributed power supply systems providestable electric power over reliable power grids,even for power generated by natural energysources, including wind and water.• Wind power generation• Hydroelectric power generation• Wave power generation• Tidal power generation• Biomass power generationOur power generating equipment is not only foremergency use. It also plays an active role atfinancial institutions and data centers. And withthe application of our electric switchboards, whichemploy our proprietary high-speed switchingtechnology, we deliver de-facto uninterruptedswitching between commercial power suppliesand power generators.• Continuous power generation systems• Emergency power generation systems• High-speed power supply switching systems• Power generating equipment• Steam turbine power generating equipment• Diesel generating equipment• Gas turbine generating equipment• Gas engine generating equipmentworldProduct examplesPower generating equipment for distributed power suppliesRS-422FA controllerOPCN-1VF66B seriesinverterVF66B VF66BμGPCdsPPLC-type DSP controllerDC motorTouch panelVF66CH/CH66DC power supply equipment (battery simulator)DSD seriesLow-inertia motorVF66SV VF66B(DC drive mode)S-curve acceleration/deceleration rate restrictionInput (mr00006) S-ARC = Output (mr00002)This controller has complete program compatibility Easy-to-understand μGPC language and rich open networksMATLAB/Simulink* for improved productivity on aμGPCdsPVF66CinverterTest item: TransmissionS-DSD high-speed, low-inertia motorControl block by MATLAB/Simulink*Delivers a high-torque response of 1,500 Hz, as well as an output frequency of 1,500 Hz. Delivers a speed control range of 1 to 10,000. Offers a high resolution of33,554,432 p/r thanks to the use of a 25-bit 30 kW or higher models are equipped with a battery simulator mode.High-speed, high-response, high-frequency inverterVF66CHigh-capacity AC servo ampVF66SVDC power supplyVF66CH CH66InverterLineupThe DC drive mode of the intelligentinverter VF66B makes it possible to drive a DC motor even though it is an inverter.Inverter with DC motor drive functionVF66B DC drive modeVF66B DC drive modeThe DC drive mode of the intelligent inverter VF66B makes itpossible to drive a DC motor even though it is an inverter. It canThyristor board DC motorVF66B(DC drive mode)DC motorVF66B ED motorconstruction time!μGPCdsPS-DSD series motor Direct-drive motorRotation position commands and rotation speed commands are sent via our proprietaryFor high-precision draw and sync control Minimizes delay between sections whenGenerates and outputs rotation position commands using A, B, Z, and phase signals For high-precision draw and sync controlMinimal delay between sections when0s＋2.84ｋ＋1.2ｋ－2.8ｋ10s20s30s40s50s60s70s430digit-430digitSpeed commandM o t o r s p e e d [m i n ]P o s i t i o n e r r o r ΔP [d i g i t ]Position error ΔP [digit]External view ofRotation position error in sync controlVF66CH CH66During power running During regenerative operationGovernor control mode200 V Class 11 to 180 kW 400 V Class 11 to 1,000 kW200 V class 200 to 220 V 400 V class 440 V to 500 V 200 V class 350 V 400 V class 700 V Triangular wave comparison PWM method ± 5% or less (settling)Voltage distortion:5% or less Voltage distortion: 5% or less Prime moversWindturbineTurbine Waterwheel(Interconnected system function)22Motor LineupPermanent magnet synchronous motor5.5yen 4504003503002502001501005007.5111518.522303745557590110132160200250315375Speed: 100%, Load rate: 80%, Operating rate: 85%, Cost: 10.35 yen/kWhDirect Drive MotorenvironmentVF66SV servo ampDiagram of application to a film manufacturing systemfrom troublesome gear maintenance and contributes to low-noise systems that last longer.Dynamic spin dynamoLow-Inertia Motor (DSD SeriesRenewable energy-3.01500Ａ/0dB-33.010.0Hz 2.0kLOGMAG dBVrmsHarmonics guideline valuePower generation system using clean, renewable energiesWe deliver some thirty of these units to customers, including banks, each year.Control panels forPre-maintenancePost-maintenanceMaintenanceMaintenance and consumable parts to keep equipment running optimallyIt is extremely important to conduct diagnostics and maintenance on a regular basis to keep your electric equipment running optimally at all times. And having this job done by technicians well versed in advanced function/advanced performance products and who use their experienced eyes to spot problems keeps it all running in peak condition.Total Supportthen impregnating insulation material and replacing bearings and other components.Total support available from Toyo Denki GroupPre-renovation Pre-renovation Post-renovationPost-renovationExample of water supply equipment updateExample of electric part update for an electrical wire processing machineReform & RenewalRenovations for improving productivity and safety updates for life cyclesIn response to social demands, equipment at variousfacilities is constantly being renovated and updated to meet needs such as improving productivity, upgrading systems, securing operational safety, reducing production costs by lowering energy expenses, and reducing CO 2 emissions to achieve environmentally friendly operations. We take the customer’s perspective on these needs and meet them by combining our latest technologies with our field know-how. We then propose the most rational renovations and updates based on the unique lifecycle of each customer’s equipment and facilities.Examples of renovations and updates● Conversion from DC to AC motors (inverter drive)● Conversion of AC commutator motors to inverter drives ● Updating of electrical parts that are no longer made ● Updating of worn controllers, including PLC● Conversion of fixed-speed drive equipment to variable speed● Conversion of mechanical transmission to electric transmission● Updating of electrical equipment that has reached its maximum service lifeUpdating the control panel and the motor to the latest inverter drive creates a system that saves energy and has low pressure variabilityUpdating the DC motor to ED motor drive saves energy and reduce maintenance34This brochure and its contents are subject to change without notice.Head officeTokyo Tatemono Yaesu Building 1-4-16, Yaesu, Chuou-ku, Tokyo, 103-0028, Japan Industry Business UnitTel: +81-3-5202-8133 FAX: +81-3-5202-8150www.toyodenki.co.jp/enJQA-0417CM009JQA-EM6541IKE073C-A18-03-500AZ。
速度调节远程监控系统的皮尔卡玛说明书
Design of Speed Regulation Remote Monitoring System of Belt ConveyorWang NingSchool of Logistics Engineering Wuhan University of TechnologyWuhan, ChinaE-mail:**********************Hu JuanSchool of Logistics Engineering Wuhan University of TechnologyWuhan, ChinaE-mail:****************Abstract—Intuitively display system operation parameters are the basis of the implementation for belt conveyor speed regulation and energy-saving control. This paper presents a speed regulation remote monitoring system of belt conveyors based on PLC and king view technology to meet the requirements of visibility, real-time and accurately for belt conveyor speed regulation remote monitoring. This system consists of a hypogyny machine system which considers hardware module as a unit and an upper machine system considering software entities as a unit. Between the upper machine and the lower machine, this paper uses PPI (Point - to - Point) to monitor data remote communication. First, design the structure of speed regulation remote monitoring system of belt conveyor, then design control process of the system, the communications between king view and Siemens S7-200, and king view interface. This system will help to research belt conveyor remote intelligent control of motor speed, then promote energy conservation and emissions reduction about the ports and the enterprises, and realize downsizing efficiency.Keywords- Belt-speed Control; Monitor and Control System; King View; Frequency Conversion Technology; Tape Speed ControlI.I NTRODUCTIONChina is a world ports country, by the end of 2011, China already has 31,968 production berths, and port cargo throughput and container throughput ranked first in the world for nine consecutive years[1]. At the same time, the port original extensive expansion mode has made energy consumption and environmental problem increasingly prominent. The society has more voices about energy saving and resource -saving for the port industry and environment-friendly construction of the port industry in the port. Bulk material handling is the biggest factor which affects the energy consumption of ports.As a port bulk continuous conveying equipment, belt conveyor system are usually configured according to the maximum traffic, when the belt traffic volume changed, constant speed operation mode will make the serious waste of the system energy. In recent years, with the development of frequency conversion technology, Adjustable belt speed runs great potential for energy saving control technology based on real-time load conditions[2].Inverter is Electrical control equipment that using frequency conversion technology and microelectronic technology to control the ac motor by changing the way of power frequency motor work. IGBT inside the inverter by breaking to adjust the output voltage and frequency power supply, according to the actual needs of the motor to provide power supply voltage it needs, thus achieving the purpose of energy, speed, in addition, the protection of the inverter and there are many functions, such as over-current, over-voltage protection, overload protection, etc. With the continuous improvement of industrial automation, the inverter also got very extensive application.In the frequency control, often using voltage source inverter, its working principle is: the voltage and frequency of the three phase alternating current fixed after the uncontrolled rectifier bridge into pulsating direct current, pulsating direct current and then filtered by reverse variable convert DC frequency-tunable, adjustable voltage equivalent AC output to the asynchronous motor. Since the power supply frequency is proportional to motor speed by changing the frequency of the power output, adjust the motor speed, to achieve smooth and stepless speed regulation.The basic principle of frequency control technology is based on the proportional relationship between the motor speed and the power supply input frequency:n = 60 f (1-s) / p （1）n—rotational speedf—the input frequencys—motor slipp —motor pole pairsWhen the frequency f is continuously adjustable (usually for a set number of P), the motor synchronous speed are continuously adjustable.For the induction motor rotor speed is always slightly lower than the synchronous speed, therefore, when the synchronous speed continuously adjustable, asynchronous motor rotor speed is also continuously adjustable. The inverter is by changing the f (frequency current) to make the motor drive.At present, there are two ways about monitoring belt conveyor system: unit monitoring and centralized monitoring. However, no matter which kinds of means used, monitoring information are not intuitive display belt conveyor operation parameters, unable to meet the need of requirements of remote monitoring, real-time visibility speed regulation and energy saving[3]. Taking into account the above-mentioned problems and the high costInternational Conference on Logistics Engineering, Management and Computer Science (LEMCS 2015)about bulk material handling test in the actual bulk handling process, the difficulty is big, the author has developed a set of belt conveyor speed energy-saving remote monitoring test system. The system is based on local / remote switch control mode to build a remote control conveyor system network, Using programmable logic controller (PLC) to complete a remote control cabinet hardware design, and using King view to design the belt conveyor remote control interface, which achieved the center to control remote frequency control conveyor belt speed . System will be good for belt conveyor speed regulation and energy saving control strategy research[4]. II.M ONITORING SYSTEM HARDWARE ARCHITECTURE Belt conveyor automatic energy-saving operation, the key to its implementation is by controlling the speed of the conveyor, to implement the conveyor soft start, stop, power balance and energy-saving operation [5].In this paper, based on PLC, the frequency control of motor speed technology for energy-saving control of the belt conveyor is presented. This system consists of PLC programmable controller, inverter, tape speed sensors and motor current sensor and other components. The system consists of can be roughly divided into the following three units[6]:∙The detection unit. The motor current signal from the current sensor obtained in the motor; tapespeed sensors are responsible for collecting thetape speed signal, and then converted into avoltage signal via f/v, all signals are transmitted tothe PLC of the A/D module.∙The control unit. When the PLC receives the detection signal, which will be judged decisions, atthe same PLC will complete conveyor soft start,the power balance and energy-saving speed andother functions.∙The execution units. When the inverterreceives the frequency control signals from the PLC, willbe in accordance with the prescribed thecorresponding frequency signal output voltage ofthe load on the motor,, so as to realize thefrequency control of motor speed of the motor,thus can complete the functions of belt conveyor.Remote monitoring system of belt conveyor speed regulation and energy saving structure are shown in Fig. 1.Figure 1. system basic structureA.Control design of the belt conveyorBelt conveyor control circuit diagram of the system is shown in Fig. 2, .Belt of A and B, respectively, started by the motor M2 and M1, motor M1, M2, respectively are controlled by the contactor KM1, KM2, KM3, KM4. KM1, KM2 control belt A positive &negative, respectively (KM1 reversal, KM2 is turn), KM3, KM4 respectively control belt B positive &negative (KM3 reversal, KM4 is turn). SB11 is the reverse start button of belt A; SB12 is the positive start button of belt A; SB13 is the stop button of belt A.SB21 is the start button for the reverse of the belt B; SB22 is the belt B of the forward start button.Two electric motors are made short circuit and fuse and the thermal relay overload protection, two in any one overload failure, another electric motor will cease to function.B.Connection design of upper machine and lowermachineThe control system can be a pair of belt integrated control system. This system has many advantages: parameters set flexible, easy to control, maintainability, a variety of control portfolio, with a belt comprehensive protection and monitoring PC screen and so on, which is a belt conveyor system overall control program of bulk materials.The system displays the site environment and the quality of materials, belt speed and other parameters through the PC and the control center display, and can be able to power the belt frequency control, to achieve the desired constant speed, and then achieving energy savings.This system chooses the ABB inverter ACS510-01, this kind of frequency converter has a general software tools with fieldbus general customers and process interface, specification design, debugging and maintenance. It is built RS485 interface, connecting other devices with Modbus protocol, within easy parameter setting, you can use the Modbus RTU protocol. Hardware, 28-32 terminals for RS485 communication of frequency converter, using the shielded twisted-pair cable connection, thus can realize the system communication.The system uses a combination of hardware and King view software, through a machine up and collaborative working mode to realize remote belt conveyor speed control, including the hardware module as a unit of a machine system and software entity as the unit of the upper machine system[7]. The machine system with Siemens PLC (Programming Logical Controller) and intelligent control equipment such as ABB inverter as the core, completed the control of the motor controlled object. Upper machine system uses king view software as the platform, for communication up and down the monitor bit machines connected via field bus technology, and then collect data through man-machine interface in front of the operator to complete the real-time monitoring of the belt conveyor.Figure 2. Belt control circuit diagramAfter the conveyor remote speed control process, the process can start the motor circuit breaker closed manually, by the control center operator control interface PC click the Start button in the implementation. The PC startup command is a serial port to send the R232 or R485 to PLC, once the PLC receives startup command, you can output a high-level digital signals, to prompt contactor solenoid is energized. After this drive is powered by the serial port can receive R232 transmission to the start command to control the motor power, the motor drive in accordance with the internal preset start time to complete the soft start. When the conveyor system gradually reaches the rated speed, this operator can change the control parameters to achieve speed control through the PC control interface in real time.III.S YSTEM SOFTWARE STRUCTUREBefore Industrial control system control mode is mainly to embody and completed by software program. This section focuses on the software programming of PLC control system and human-machine interface of configuration design, making the belt set control system on the basis of the hardware configuration is complete to achieve the required control function. System Control mode is local / remote control with switchable, mainly remote monitoring applications.∙Local control: without the aid of PC applications, directly by the operator through the PLC controland variable speed belt conveyor start-up, torealize the normal control system, but not for real-time monitoring the running state of belt conveyor;∙Remote control: with manual control and automatic control modes on the PC screen. Theautomatic control of PLC according to the signalfrom the sensor output frequency of self- controlmaterial transport speed; Manual control is aresponse to an operator according to what you see,start, stop, and reversing and speed controlcommand, so as to realize the control of beltconveyor.A.King view communication with Siemens S7-200King view software as an excellent PC monitoring software, in many areas are widely used in remote monitoring[8]. King view regards every communication device as an external device, building a large number of device drivers as the communication interface to external devices to realize communication and external equipment. During the development process, according to equipment configuration wizard, step by step to complete the connection, configuration king and corresponding external device drivers can be realized.King view driver using ActiveX technology, every driver is a COM object, this way make drivers and king view constitute a complete system, thus ensuring the efficient operation of the system[9]. Between the king view and PLC in this system uses the PPI (Point - to - Point) way of communication. This mode is designed forSiemens S7-200 series developed a communication protocol, a master / slave protocol, PC machine-based station, S7-200 as slave.B.King view interface design processFirst, create a new project, make COM1 serial port settings, and then define the configuration king data variables.Variables can be divided into two categories, basic type and special type. Basic type of variables is divided into two kinds of memory and I/O variables. The data collected from the lower machine, sent to the next bit machine instructions, such as belt conveyor speed, the power switch variables, all needs to be set to "I/O variables". Those who only use the variable within the king view, such as the calculation process of intermediate variable, can be set to "memory variables”.The basic types of variables can also be in accordance with the data type is divided into discrete, real, integer and string. After set the variable, then start to make graphic image, and graphics animation connection.IV.M ONITORING SYSTEM DEBUGGING ANDDEMONSTRATIONThe monitoring system is a modular, researchers should adopt the method of single step debugging[10]. That validate the working process and the logical relationship from the stand is correct. First, build communication and choose communication mode in advance. After selecting the desired item, click “Test” options for network connectivity tests,including network transfer rate, the highest station address, the maximum and minimum delay time, setup time and so on.After all parameters meet the practical requirements, click on the communication icon then working screen appears, to establish a network of communication between the personal computer and the device.After the communication is established, researchers will download the program from the computer to the PLC, and then start debugging.Before the debugging process, researchers should remember that researchers must transform the PLC from the stop mode to run mode. In the upper machine to the next bit machine communication, ensure the correctness of the PLC control cabinet wiring at first, and then debug. After accurately select the remote address, download the program to the PLC, the following can be carried out automatically on the system hardware debugging upcoming LS1 into automatic mode , PLC in run mode , then click the " view of the state " . . In the state diagram of new numerical can fill in the required value of the variable, and controlled.Figure 3. Part of test-bed experimentFigure. 3 shows the testing stand part of the experiment. The trial showed that PC connects the lower machine by a communication protocol, and then controls belt conveyor. When researchers enter each parameter data on the host computer interface, then clip “start”, it will drive belt to the desired speed positive &negative, and collect the required data in real time.Figure 4. Speed curveFigure.4 is the certain speed curve in the process of the experiment shows. In this system, belt conveyor drive shaft connected to the speed sensor and application of the pulse sensor and converter module connected to through computer programming, to achieve the purpose of collecting the real-time speed of belt conveyor.In this system, GSG8 mine speed sensor is used to detecting the speed, installed under the belt conveyer belt, for wire rope to tighten the speed wheel contact with the tape. When under the influence of the speed sensor in the encoder to produce light and light signal, the signal after amplification can produce high and low level pulse, thenspread to the PLC, the processed generates the output signal.V.C ONCLUSIONBased on system design method described above, the author designed a monitoring system containing a PC interface, a lower control monitoring system and its supporting software required monitoring system.This system has realized the function that king view software control belt conveyor on-site and remote through the PLC control cabinet, and can be realized using the PC interface to collect data, generate reports and other features. Actual running results show that the monitoring system is simple and convenient operation, operating normally, PC terminal cooperate well with PLC and frequency converter, transmission of data acquisition and control commands are accurate, and the whole control system is stable and reliable performance.A CKNOWLEDGMENTThis work was supported by the Ministry of transport a nd applied basic research project of China (key platform gr ant No. 2013329811340), the Natural Science Fundation of the Jiangsu Higher Education Institution of China (Grant No. 14KJB5800 08), the Nature Science Foundation of Na ntong (Grant No. BK2014017).R EFERENCES[1]The ministry of transport of the People's Republic of China.China's shipping development report 2011 [M]. Beijing: people's traffic press, 2012:24 to 29.[2]Zhang Tongxu, Xie Wenning. Port energy-saving reform of thebelt conveyor technical measures [J]. Journal of Marine science research, 2008, (1) : 34-38.[3]Tan Chao. Dong Xiaojun. Based on virtual reality technology ofremote monitoring system of underground belt conveyor. Coal mining machinery, 2009.30 (11).[4]M. A. Alspaugh. Latest developments in belt conveyor technology[C], MIN-Expo 2004, Las Vegas, NV, USA, 27-30 Sept.,2004.[5]Zhang S, Tang Y. Optimal scheduling of belt conveyor systems forenergy efficiency—With application in a coal-fired power plant[C].Control and Decision Conference (CCDC), 2011 Chinese.IEEE, 2011: 1434-1439.[6]Zheng Fengyi. The illustration of Siemens S7-200 series PLCapplication in 88 [M]. Electronic industry press, 2009.[7]Wang Yu. PLC control and configuration design [M]. Electronicindustry press, 2010.[8]Su Yun, Pan Feng. Remote control system based on king view andPLC [J]. Industrial instrumentation and automation devices, 2004(2) : 53-55.[9]Wang Shanbin. Configuration software application guide -Kingview Kingview and Siemens WinCC. [M]. Chemical industry press, 2011.[10]G. M. Wang , X. J. Luo. Design and debugging of communicationbetween controller and King view based on CAN bus. World Journal of Engineering, 2013, Vol.10 (4), 395-400.。
The Science of Electric Motors and Generators
The Science of Electric Motors andGeneratorsElectricity has become an integral part of our daily lives. From powering our homes to running industries, electricity has become an indispensable resource. The backbone of the modern electrical system is the electric motor and generator. These devices are responsible for converting electrical energy into mechanical energy and vice versa. The science of electric motors and generators has come a long way since their inception. In this article, we will explore the history, working principles and types of electric motors and generators.History of Electric Motors and GeneratorsElectric motors and generators are not a modern invention. The history of electric motors can be traced back to the early 1820s when Danish scientist Hans Christian Oersted discovered the relationship between electricity and magnetism. In 1822, British scientist William Sturgeon invented the first practical electromagnet, which is the core component of electric motors and generators.Michael Faraday, a renowned British physicist, made several breakthrough discoveries in electricity and magnetism. In 1831, Faraday discovered the principle of electromagnetic induction and invented the first generator. Faraday's generator was a simple device consisting of a copper disc rotating between two magnets. As the disc rotated, it generated a current that flowed through a wire connected to the disc.Working Principle of Electric MotorsElectric motors are devices that convert electrical energy into mechanical energy. The working principle of electric motors is based on the interaction between magnetic fields and current-carrying conductors. Electric motors consist of a stationary part called the stator and a moving part called the rotor. The stator contains several coils of wirearranged around the perimeter of the motor, while the rotor is a shaft mounted inside the stator.When a current flows through the stator coils, it creates a magnetic field. The rotor, which is made up of a series of magnetic poles, is attracted by the magnetic field and begins to rotate. As the rotor rotates, the north and south poles alternate in front of the stator coils. This action creates a continuous repulsion and attraction of the rotor and stator, which drives the rotor to continue to rotate. The rotation of the rotor is used to power different types of machinery.Types of Electric MotorsThere are several types of electric motors, each designed for specific applications. Some of the most common types of electric motors include:1. DC Motors: These are the simplest types of electric motors and operate on direct current (DC). DC motors are commonly used in small appliances, electric vehicles, and industrial machinery.2. AC Motors: AC motors operate on alternating current (AC) and are commonly used in homes, businesses, and industrial applications. These motors are more efficient than DC motors and require less maintenance.3. Servo Motors: Servo motors are used in precision applications such as robotics, automation, and electronics. These motors are controlled by feedback signals and can rotate to precise positions.4. Stepper Motors: Stepper motors are used in applications that require precise positioning. These motors rotate in small steps and are commonly used in printers, scanners, and CNC machines.Working Principle of Electric GeneratorsElectric generators are devices that convert mechanical energy into electrical energy. The working principle of electric generators is based on Faraday's principle of electromagnetic induction. An electric generator consists of a rotor, which rotates inside astationary coil of wire called the stator. The rotor is connected to a shaft that is driven by an external force such as steam or water.As the rotor rotates, it creates a changing magnetic field that induces an electric current in the coil of wire inside the stator. The output voltage and current of the generator depend on the speed of the rotor and the strength of the magnetic field.Types of Electric GeneratorsThere are several types of electric generators, each designed for specific applications. Some of the most common types of electric generators include:1. AC Generators: AC generators are the most common type of generators and operate on alternating current. These generators are commonly used in homes, businesses, and industrial applications.2. DC Generators: DC generators operate on direct current and are commonly used in electric vehicles, marine applications, and remote power generation.3. Standby Generators: Standby generators are used as backups to provide emergency power in the event of a power outage. These generators are commonly used in hospitals, data centers, and other critical facilities.ConclusionElectric motors and generators are an essential part of our modern world. They power everything from tiny toys to massive industrial machinery. The science behind electric motors and generators has come a long way since their invention in the early 19th century. With advancements in technology and materials, these devices have become more efficient, reliable, and cost-effective. Understanding the working principles and types of electric motors and generators can help us better appreciate the role they play in our daily lives.。
MOTORTRONICS TM Solid State AC Motor Control MVF S
M O T O R T R O N I C ST MS o l i d S t a t e A C M o t o r C o n t r o lN O T I C ER E A D A N D U N D E R S T A N D T H E S E I N S T R U C T I O N S B E F O R E A T T E M P T I N G A N Y U N P A C K I N G ,I n s t r u c t i o nM a n u a lM e d i u m V o l t a g e V a c u u m C o n t a c t o r7.2k V / 400ASafety PracticesThis instruction manual applies only to the MVF Series Vacuum Contactor regarding installation and maintenance procedures.Installing and maintaining these products improperly may result in serious personal injury, property damage, or even death. Therefore this instruction manual must be read and understood at every step in unpacking, assembly, operation, and maintenance of contactors.Only qualified persons familiar with installing and maintaining contactors are permitted to work on contactors, and this instruction manual should be accessible to those persons at all times.If further information is required, please contact Motortronics Inc.LabelsLabels used in this instruction manual are DANGER, WARNING and CAUTION depending on the situation.Safety Practices during OperationSafety Practices during OperationTable of ContentsSafety Practices (1)1. General (4)1.1 Specification1.2 Operating Time & Current1.3 Control Voltage Range1.4 Rated Current of Auxiliary Contact1.5 Additional Ratings1.6 Application Condition1.7 Ordering System1.8 Application Considerations2. Receiving/Handling/Storage and Installation (6)2.1 Receiving2.2 Handling2.3 Storage2.4 Installation2.5 Inspection before Operation2.6 Tightning Torque for Bolts3. Structure and Explanation of Operation (8)3.1 Structure3.2 Explanation of Operation3.3 Structure of the Vacuum Interrupter3.4 Structure of Cradle Type and Interlock3.5 Inserting & Withdrawing3.6 Control Circuit Diagrams4. Inspection and Maintenance (14)4.1 Visual Inspection (every 1-6 months)4.2 Periodic Inspection4.3 Checking Vacuum and the Contact Erosion Limit4.4 Replacements for Main Components4.5 Troubleshooting5. Specification Overview (22)6. Dimensions (23)1. GeneralThe MVF Series of Vacuum Contactors are suitable for switching and controlling 3-phase motors with squirrel cage or slip ring rotor, capacitors, and transformers. These are designed and manufactured to withstand frequent switching.1.1 Specification1.2 Operation Time & Current1.3 Control Voltage Range1) Closing: 85-110% of rated voltage2) Opening: 75-110% of rated voltage (latching type only)1.4 Rated Current of Auxiliary Contact1.5 Additional Ratings1.6 Application Condition1) Ambient temperature: -5°C to 40°C (23°F to 104°F) 2) Relative humidity: below 85%3) Altitude: less than 1000m (3281ft) A.S.L (Above Sea Level)Please contact us for the special applications.1.7 Ordering System1.8 Application Considerations1) Verify the voltage and current requirements of the load are within the specified ratings of the contactor.2) The vacuum interrupter should be replaced after 1,000,000 operations. If the contactor is not protected by fuses, the vacuum interrupter should be replaced if they have interrupted fault currents at or near their maximum interrupting rating.2. Receiving/Handling/Storage and InstallationMVF Series Vacuum Contactors are subjected to complete factory production tests and inspection before packing. They are shipped in packages designed to provide maximum protection to the equipment during shipment and storage.2.1 ReceivingWhen contactors are delivered, receivers should examine the contents for any signs of damage such as broken, missing, or loose components. If damage or loss is detected, notify our nearest office or representatives and file a claim with the freight carrier.Inspection after unpacking:1) Check the type rating and quantities with the specification sheet.2) Check contactors for any damage or missing materials.3) Check all the accessories and spares supplied.2.2 HandlingContactors must be handled with care to avoid damage. Ensure that vacuum contactors do not suffer impact or other physical stress during handling. Contactor damage may cause serious harm to both persons and property.2.3 StorageStore contactors in a dry, dust free, and well ventilated room. Contactors should be stored in the open condition.2.4 Installation1) Confirm the type and rating, check for damage, and clean contactors with a dry cloth, before installingcontactors into the switchgear.2) Mount contactors securely on a flat surface. Refer to section 6 of this manual for dimensions and section 2.6 fortorque requirements.3) Clean the connecting surfaces with a dry cloth, and then connect the 3 phase cables/buses and earthterminals. Be careful not to impact the enclosure or contactor with the cables or bus.2.5 Inspection before Operation1) Confirm contactors are installed properly. If not, install contactors again according to section 2.4.2) Operate contactors a few times manually to ensure that contactors close and open smoothly. Then, operatecontactors electrically in the test position, and confirm that the ON/OFF indicator works properly.3) Confirm that no tools and materials are left near the contactor.2.6 Tightening Torque for Bolts3. Structure and Explanation of Operation3.1 StructureFig. 3-1 is the section-drawing of the mechanism part in the MVF Series Vacuum Contactor. Fig. 3-1Close Condition Open Condition① Closing coil ⑤ Tripping spring② Moving core ⑥ Pressing spring③ Main shaft ⑦ Vacuum interrupter④ Pressing plate ⑧ Insulation frame3.2 Explanation of Operation1) Closing■ When the closing coil ① is energized, the moving core ② moves toward the closing coil and compresses the opening spring ⑤. At the same time, the pressing plate ④, which is fixed on the main shaft ③, pushes the pressing spring ⑥, so the movable stem of the vacuum interrupter ⑦ is moved up to make the CLOSED condition.■ For latched type (mechanical latching), the latch device holds the moving core of the contactor closed against the closing coil after the contactor is energized (closed) and the control source is removed.2) Opening■ For continuously energized types, if the closing coil is de-energized by the OFF signal and the opening spring is released to the OPEN condition, then opening of the contactor is completed.■ For latched type, if the trip coil is energized by OFF signal or the trip button is pushed, the hook roller of the latch device is released and the moving core moves to OPEN condition by the opening spring.3.3 Structure of the Vacuum Interrupter3.4 Structure of Cradle Type and Interlock1) Structure of cradle typeFig. 3-3 is the cradle type of MVF Series Vacuum Contactor.① ON/OFF indicator, ON means closed condition, OFF means open condition.② Counter, The counter (when present) shows how many times the contactor has operated since it was made.The counter may read 100 when you receive the contactor, because it was tested after manufacturing.③ Control plug. The control source is supplied through the control Jack.④ Draw-out button⑤ Fuse. Fuses prevent the magnification of the short-circuit current.⑥ Fuse holder⑦ Fuse melting detector. The fuse melting detector can show electrically whether the fuse has blown or not.⑧ Manual checking hole. A manual checking hole is used to close the contactor manually.⑨ Emergency trip button. Only the latched types have the trip button which is used in emergencies.⑩ Latch device⑪ Front cover⑫ Name plate⑬ Position switch. The position switch indicates electrically whether the contactor is in the TEST or CONNECTION position.2) InterlockFig. 3-4Closing coilTest or Connection position /Closing coilTest or Connection positionInsertion or WithdrawalTest or Connection position3.5 Inserting & Withdrawing1) How to insert the contactor in the E, F cradle .■ InsertingSet the wheels of the contactor exactly on the guide rail of the cradle. The lifter should be used when the contactor is lifted in order to install it into switchgears.When the contactor reaches the TEST position, the interlock pin prevents the draw-in at this position. Push the draw-out button (Fig. 3-5) and then insert the contactor to the CONNECTION position. If the contactor is in the correct position, the interlock pin is in the hole on the interlock support and the female contact will be inserted fully into the terminal. Fig. 3.5■ WithdrawingWhen a contactor is withdrawn, the contactor cannot be operated because of the interlock. In OPEN condition, push the draw-out button (Fig. 3-5) and pull out a contactor to the TEST position.Draw-out button Interlockrelease bar3.6 Control Circuit DiagramsContinuously EnergizedLatchedLatched (AC Open Control)CC: Closing coil SCU: Source control unit CTD: Condensor trip device TC: Trip coil CL: Electrical interlock Aux. SW: Auxiliary switch4. Inspection and MaintenanceMaintenance shall be carried out to ensure trouble-free operation and achieve the longest possible working life of the contactors. MVF Series Vacuum Contactors are characterized by their simple and robust construction and have a long life expectancy. Their operating mechanisms have a low maintenance requirement, and the interrupters are maintenance-free during their working life. The maintenance is determined by environmental influences, switching frequency, and so on. 4.1 Visual Inspection (every 1-6 months)The purpose of the visual inspection is to confirm normal operation and should be performed every 1 to 6 months depending on duty service.4.2 Periodic Inspection4.3 Checking Vacuum and the Contact Erosion Limit1) Checking the vacuumThe low pressure in the vacuum interrupter is guaranteed for over 30 years of service. That means the vacuum interrupter is maintenance-free. But if necessary, it can be checked by a vacuum tester.2) Checking the contact erosionSince the contacts are contained inside the interrupter, they remain clean and require no maintenance. However, during high current interrupting, there may be a minimum amount of erosion from the contact surfaces. To check the erosion of the interrupter contacts and carry out the following operations.■ Close the contactor.■ Open the rear cover (if the contactor has a rear cover).■ Measure the distance between the dish washer and the pressing plate. With new interrupters this distance is about 0.047 – 0.059 inches (1.2-1.5 mm). If it is reduced to 0.020 inches (0.5 mm), the three interrupters must be replaced. Checking the contact erosion is important to evaluate the efficiency of the interrupters. (Refer to the Fig. 4-1)Fig. 4.14.4 Replacements for Main ComponentsRemove the contactor from the enclosure to ensure that all high voltage sources are disconnected. 1) Replacing the fuse■ Renew the fuses. The fuse must have the striker facing towards the front cover.■ If new fuses are longer than old ones, rear fuse holders can move 100 mm backward. Insert new fuses and tighten the bolts.■ Reverse the action in the previous step if the new fuses are shorter.Fig. 4.2 Replacing the fuse2) Replacing the closing coilThe contactor employs a pair of magnet coil for each contactor. ■ Remove the moving core. (Fig. 3-1 ②) ■ Remove the rear cover .■ Pull out control plug o f the closing coil ②. ■ Loosen the bolts ⑤, fixing the closing coil.■ Remove the failed coils out toward the front cover. ■ Insert the new coils.■ Connect the leads of the closing coil. ■ Reinstall the moving core and rear cover.■ After reassembling, ch eck the operation of the contactor electrically.Fig. 4-3① Coil support ② Closing coil ③ Rear plate ④ Coil core ⑤ Bolt⑥ Gap plate ⑦ Stainless ⑧ Rubberplate3) Replacing the auxiliary switch■ Release the support ① and remove the wires from the auxiliary switch. ■ If auxiliary switch ② needs replacing, release the bolt and cable. ■ Replace the failed auxiliary switch.■ Reverse the action in the previous step and check the operation of the switch manually using the manual checking hole. (Fig. 3-3 ⑧)■ Check the operation of the switch electrically.Fig. 4-4① Auxiliary switch support ② Auxiliary switch4) Replacing the vacuum interrupter■ Release the pressing plate.■ Release the Insulation rod ② from the vacuum Interrupter ⑤, and separate the flexible connector ④. ■ Loosen the upper fixing bolts from the upper connector ③. ■ Replace the new vacuum interrupter ⑤.■ Reverse the action in the previous step and check the stroke and wipe of the vacuum interrupter.Fig. 4-5① Pressing plate ② Insulation rod ③ Upper connector ④ Flexible connector ⑤ Vacuum interrupter5) Replacing the source control unit■ Open the rear cover (if the contactor has a rear cover).■ Remove the cable tie.■ Pull out (disconnect) the control plug. (Fig. 4-6)■ Release the fixing bolt. (Fig. 4-7)■ Replace the control unit. (Fig. 4-8)■ Reassemble reversely.Fig. 4-6Fig. 4-7Fig. 4-84.5 Troubleshooting5. Specification Overview6. DimensionsDimensions specified in mm (inches).Dimensions specified in mm (inches).For the latest product information visit Phasetronics Inc. dba Motortronics 1600 Sunshine DriveClearwater, Florida 33765USATel: 727.573.1819 or 888.767.7792 Fax: 727.573.1803 or 800.548.4104 E-Mail:**********************User Manual Rev: 1.01 – Jul 15th 2015M O T O R T R O N I C S T MS o l i d S t a t e A C M o t o r C o n t r o l M V FS e r i e sM e d i u m V o l t a g e V a c u u m C o n t a c t o rP h a s e t r o n i c s I n c.d b a M o t o r t r o n i c s1600S u n s h i n e D r i v eC l e a r w a t e r,F l o r i d a33765U S AT e l:+1727.573.1819o r888.767.7792F a x:+1727.573.1803o r800.548.4104w w w.m o t o r t r o n i c s.c o m。
电机与变压器英语练习题
电机与变压器英语练习题一、词汇填空1. The ___________ is a device that converts electrical energy into mechanical energy.2. A ___________ is an electrical device that changes the voltage of an alternating current.3. The ___________ of a motor is the rotating part that converts electrical energy into mechanical energy.4. The ___________ of a transformer is the ratio of the number of turns in the secondary coil to the number of turns in the primary coil.5. ___________ is the process of reducing the voltage of electrical power for distribution.二、选择填空1. Which of the following is NOT a type of motor?A. DC motorB. AC motorC. TransformerD. Induction motor2. The primary function of a transformer is to:A. Increase voltageB. Decrease voltageC. Convert AC to DCD. Store electrical energy3. In a threephase motor, the number of poles is determined :A. The frequency of the power supplyB. The voltage of the power supplyC. The speed of the motorD. The type of motor4. The slip of an induction motor is:A. The difference between synchronous speed and actual speedB. The ratio of actual speed to synchronous speedC. The ratio of synchronous speed to actual speedD. The difference between rated speed and actual speed5. Which of the following is a type of transformer cooling method?A. Air coolingB. Water coolingC. Oil coolingD. All of the above三、阅读理解Passage:1. What is the main function of a motor?2. What are the two main types of motors?4. Why are AC motors widely used in industrial and residential settings?四、翻译1. 变压器是一种静止的电气设备，用于在两个或多个电路之间传输交流电能。
基于扰动观测器的永磁同步电机复合滑模控制
电气传动2018年第48卷第2期摘要：针对永磁同步电机模型参数扰动的问题，提出了一种基于扰动观测器的永磁同步电机复合非奇异终端滑模驱动控制策略。
新型控制器在传统矢量控制的基础上结合使用了扰动观测器和非奇异终端滑模控制器，是一种复合控制策略。
同时新的控制策略引入了扰动观测器进行前馈补偿，以减小控制器增益。
最后搭建了永磁电机驱动控制试验平台开展了对比试验研究，试验结果验证了新型控制策略的优势。
关键词：永磁同步电机；电机驱动系统；非奇异终端滑模控制器；扰动观测器；速度控制中图分类号：TM351文献标识码：ADOI ：10.19457/j.1001-2095.20180202Composite Sliding Mode Control of Permanent Magnet SynchronousMotor Based on Disturbance ObserverSUN Jiwei ，LIU Xiumin ，GUO Yanan（College of Information &Business ，Zhongyuan University of Technology ，Zhengzhou 451191，Henan ，China ）Abstract:Aiming at the problem of the time -varying parameters and disturbances for a permanent magnetsynchronous motor drive system ，a composite nonsingular terminal sliding mode control scheme for the permanentmagnet synchronous motor drive system was introduced.Based on the traditional vector control ，the new controller combined the disturbance observer and the nonsingular terminal sliding mode controller ，so it was a composite control strategy.And the new controller introduced disturbance observer as feedforward controller.Finally ，the comparativeexperiment was carried out on the permanent magnet motor drive control test platform.The experimental results verify the advantages of the new control strategy.Key words:permanent magnet synchronous motor （PMSM ）；motor drive system ；nonsingular terminal sliding modecontrol （NTSMC ）；disturbance observer ；speed regulationELECTRIC DRIVE 2018Vol.48No.2基于扰动观测器的永磁同步电机复合滑模控制孙继卫，刘秀敏，郭亚男（中原工学院信息商务学院，河南郑州451191）基金项目：河南省自然科学基金项目（2015140106）作者简介：孙继卫（1983-），女，硕士研究生，讲师，Email ：3572104546@在各类交流电机中，永磁同步电机（PMSM ）得到了广泛的工业应用，并具有高效率、高转矩电流比和低噪音等优点［1-3］。
AMILLMOTORINCHIN...
A MILL MOTOR INCHING DRIVE USING A THREE PULSE CYCLOCONVERTER WITH DOUBLE INTEGRAL PHASE CONTROL.by Greg Hunter1998ABSTRACTThis report describes the first commercial installation of a three pulse cycloconverter drive using a new type of phase control modulation method developed by the authors called double integral control. The new control method gives the three pulse cycloconverter similar performance in both harmonic output and speed range to a six pulse cycloconverter, but at a much reduced cost and much higher efficiency. The particular application is an inching drive for the maintenance of various mills at a large copper mine in Canada. There are 5 mills at the site, each of which is driven by one or two synchronous motors rated at 4160V 60Hz 4000 hp (3000kW). The motors are run direct on line but started as wound rotor induction motors using their damper windings, which are brought out via slip rings. The cycloconverter is rated at 0-570V, 0-10Hz, 1500A with a supply input of 600V, 60Hz. A mill to be turned for maintenance is connected to the cycloconverter with its motors configured as synchronous machines with their damper windings shorted. The cycloconverter, with its adjustable low frequency output, is then used to turn the mill as required. Starting torque for the mills can be up to 1.5 times the rated torque which dictates the high current rating of the cycloconverter. The cycloconverter is rated for continuous duty to allow for possible future applications at the site. With an efficiency of greater than 99.5%, only fan cooling is required.IntroductionAt present, practical 3 phase cycloconverter drives use a minimum configuration of three 6-pulse bridges, requiring a minimum of 36 thyristors and a transformer with three isolated three phase windings to isolate the bridges. The minimum theoretical configuration, though, is the 3-pulse circuit as shown in Fig. 1. This circuit uses only 18 thyristors, does not require a transformer, and is much more efficient than the 6-pulse configuration. Also, most of the 3-pulse related harmonics that appear on the output are in phase and so do not appear on the motor windings. At low output frequency and voltages, the motor voltages and currents are identical to those of a six-pulse cycloconverter. Traditionally, it has been stated [1] that the 3-pulse cycloconverter is not practical due to the low frequency intermodulation products which can be generated on the output. These subharmonics are completely suppressed by the use of the double integral phase control method developed by the author [2]. This phase control method also solves other problems such as control with discontinuous current and bank cross-over determination.This report is a brief description of the first commercial installation of a 3-pulse cycloconverter using the new modulation technique. The application is an inching drive for the maintenance of various mills at a large copper mine in Canada. There are 5 mills at the site, each of which is driven by one or two synchronous motors rated at 4160V 60Hz 4000 hp(3000kW). A mill to be turned for maintenance is connected to the cycloconverter with its motors configured as synchronous machines with their damper windings shorted. The cycloconverter is supplied from a 4160 to 600V transformer and is capable of producing an output voltage of up to 570V. This is enough voltage to operate the motors up to a frequency of 9Hz, so this was chosen as the maximum design frequency, although the cycloconverter itself is capable of operation at up to half the mains frequency [2]. The mills require up to 1.5 times rated torque, so the cycloconverter was designed to supply up to 1500A current. Although only intermittent duty is required for inching purposes, the drive was designed for continuous operation to allow for possible future needs. With an efficiency at full voltage and current of about 99.6%, the cycloconverter is compact and requires only fan cooling. The front and rear views of the cycloconverter cabinet, which is 2.3 m tall, are shown in Fig. 1.Figure 1. Front and rear views of the cycloconverter cabinet.Power CircuitThe power circuit of the 3-pulse cycloconverter is shown in Fig. 2. The circuit is conventional. The thyristors are arranged into three modules, one for each output phase, each complete with heat sinks and cooling fans. The modules were supplied ready built and tested by the thyristor manufacturers. They are standard modules which are also used in soft starters and have proven reliability.Control MethodThe control method used is double integral control. In this method, the output waveform for each output phase is divided into intervals called trigger periods as shown in Fig. 3, each of which contains one thyristor firing. With the exception of the trigger period immediately after a bank cross-over, the trigger period starts and finishes when the expected output waveform0.47uFΩ5050WPhase U Phase V Phase W RST UWVTO MOTORFROMTRANSFORMER Figure 2. Power circuit of the 3-pulse cycloconverterinputouput reference trigger periodt 1t f t 2v iv o v rFigure 3 Trigger periods used for double integral control.crosses the reference waveform. The trigger period after a bank cross-over starts at the time of bank cross-over to ensure full output waveform control at all times.In double integral control, the thyristor trigger instant, t f , is chosen to satisfy the equation:02211212=−+−− v v dt K t t v v dt o r tt t o r t t (1)where t 1 and t 2 are the start and end of a trigger period and v o and v r are the output andreference voltages as shown in Fig. 3. K is a stability constant, usually set to 0.5. Ignoring the right hand single integral term, which is a stabilising term normally evaluating to zero,satisfying the equation keeps the average of the integral of (v v o r −) zero. By keeping theRST Power Circuit Motor V/F Converters Reference Gate Drives Zero Current Detectors Opto-IsolatorsR-SS-T Reference GeneratorOpto-Isolators Gate Control Z.C.D.Interface V/F Counters Microcomputer Interface Microcomputer (TMS320C31based)Field Programmable Gate Array Control InterfaceA/DConv.SpeedU V WSerial Link Interface RS232Digital Controls UART ToPC Interface DisplayDISPLAY InterfaceN.V.R.Non-Volatile RAMFigure 4. Block diagram of the control circuit.average of this integral zero, the average of the motor flux error, and the average ripple current, are kept at zero. The control method is implemented in practise by evaluating the right hand side of equation (1) repeatedly from the start of the trigger period at a rate of 120times per mains input cycle and triggering the thyristor when the equation is satisfied. Using this method, rather than estimating the trigger time in advance, ensures correct triggering even when the output voltage becomes indeterminate due to discontinuous current.A major problem for the cycloconverter without circulating current is the determination of the time to cross between thryistor banks in each phase. As can be seen from the high frequency equivalent circuit of one phase of the motor shown in Fig. 5, the ripple current can be approximated by:ripple current ∝−−− ∑v v dt v v dt o r o rU V W 13,,(2)Since with double integral control, the integrals in equation (2) are known and controlled, the polarity of the ripple current in each phased is always known. The bank cross-over time is chosen to be the first time when the actual current is zero (and thus all thyristors in that phaseare off) and the polarity of the integral of v v o r −, is positive for the positive bank, or negative for the negative bank. This corresponds to the first time the current is zero after the fundamental component of the current has passed through zero, which is probably the optimum bank cross-over time.~LRback e.m.f.v o v r Figure 5 Per phase high frequency equivalent circuit of a motor with values of thecycloconverter output and reference voltages shown.Control CircuitThe control circuit of the cycloconverter is shown in Fig. 4. The control functions are implemented using a Texas TMS320C31 DSP, with an ACTEL A1225XL fieldprogrammable gate array used for all digital interface logic and a 12 bit A/D converter used to read in all analogue inputs.The double integral control method requires precise feedback of the integrals of the output phase voltages. These integrals are obtained here by counting the output pulses from three precision voltage to frequency converters. The output phase currents are also measured, but are used only for protection as they are not used in the double integral control method.WaveformsThe cycloconverter was tested with both induction motor loads and passive loads. Anexample of the waveforms obtained is shown in Fig. 6. The load for this test is a passive RL load simulating two mill motors at full load for 9 Hz frequency scaled for 100:1 of the output current and for 415V, 50Hz input rather than the final 600V, 60Hz input to suit the supply available at the test laboratory. The input transformer was also simulated with a suitable line input inductance. This inclusion is the reason for the pronounced commutation glitches which can be seen on the output voltage waveform.Note that the crossing between thyristor banks is particularly rapid and does not contribute any current distortion.-600-400-200200400600Voltage Volts -20-15-10-55 101520 0 50100 150 200Time, ms Current Amps Figure 6. Output phase voltage with respect to input neutral and output phase current for apassive load simulating two mill motors at full load.ConclusionThe first commercial installation of a 3-pulse cycloconverter drive using double integralcontrol achieved its objectives and is an economical replacement for the former mechanically switched inching technique.References1. B. R. Pelly, “Thyristor phase-controlled converters and cycloconverters”, Wiley-Interscience, 1971.2.G. P. Hunter, “New improved modulation method for a cycloconverter driving an induction motor”, IEE Proc., Pt. B, vol. 135, No. 6, pp. 324-333, November 1988.。
汽车专业英语读译教程配套6-本E-GAS-GDIELECTRONICFUELINJECTION
link between the accelerator pedal and the throttle
valve. Instead, as shown in the Figure on next page,
an accelerator sensor picks up your movement or
trust 相信，信赖 defect 故障，缺点，毛病 limp-home 跛行回家
ELECTRONIC FUEL INJECTION
Gasoline Direct Injection
Conventional gasoline engines are designed to use an electronic fuel injection system, replacing the traditional mechanical carburetion system. Multi-point injection (MPI), where the fuel is injected through each intake port, is currently one of the most widely used systems. Although MPI provides a drastic improvement in response and combustion quality, it is still limited due to fuel and air mixing prior to entering the cylinder.
But there's more. For traction control, the electronic throttle links with the ABS (Anti-lock Braking System). The same wheel- speed sensors of ABS also feed the ASR (Anti-Slip Regulator). When any driving wheel starts to slip, a slight brake application prevents that wheel from slipping so much that the differential delivers no power to the other driving wheel. If both driving wheels show signs of slipping, the electronic throttle cuts back power for maximum control gives the car the max acceleration the tires can deliver to the road. If laying down tire smoke is your thing, avoid ASR. But for making the fastest takeoff, you cannot beat it.
艾顿电子加热器说明书
Local and remote switching capabilityThe Eaton motor operator mechanism enables local and remote ON, OFF and reset switching of a circuit breaker. The motor operator is mounted on the circuit breaker cover within the dimensions of the circuit breaker. The robust motor operators offer various volt-ages to maximize customer flexibility. Standard load transfer switching can be accomplished through the use of two circuit breakers fitted with motor operators and a mechanical interlock.Features, functions and benefi tsThe motor operator provides special features for ease of cus-tomer use and status indication.•The motor operator allows the circuit breaker to be opened, closed or reset remotely •The motor operator contains a motor connected to a cam drive mechanism. The cam drives a slide mechanism to operate the circuit breaker handle•Internal limit switches and relays are used to control motor operation to prevent overdriving the circuit breaker handle and motor overload conditions•A key is provided to manually operate the circuit breaker •A special pull-out locking mechanism provides a method for padlocking the circuit breaker handle in the OFF position•The locking device will accept three padlock shackles with a maximum diameter of 1/4-inch (6.4 mm) each •The cover provides visual status of the circuit breaker: ON, OFF or TRIPPED. A PUSH-TO-TRIP button allows the user to manually trip the breakerStandards and certifi cations The motor operators are UL ா and CSA ா listed and CE marked. The table on the following page provides electrical rating data for the motor operators—E- through L-Frame.C o u r t e s y o f C M A /F l o d y n e /H y d r a d y n e ▪ M o t i o n C o n t r o l ▪ H y d r a u l i c ▪ P n e u m a t i c ▪ E l e c t r i c a l ▪ M e c h a n i c a l ▪ (800) 426-5480 ▪ w w w .c m a f h .c o mEaton Corporation Electrical Sector 1111 Superior Ave.Cleveland, OH 44114United States877-ETN-CARE (877-386-2273)© 2009 Eaton Corporation All Rights Reserved Printed in USAPublication No. PA01222002E / Z9314November 2009PowerChain Management is a registered trademark of Eaton Corporation. All other trademarks are property of theirrespective owners.Turn the Key (clockwise only)Manual Operating KeyCircuit Breaker WindowPUSH-TO-TRIP ButtonC o u r t e s y o f C M A /F l o d y n e /H y d r a d y n e ▪ M o t i o n C o n t r o l ▪ H y d r a u l i c ▪ P n e u m a t i c ▪ E l e c t r i c a l ▪ M e c h a n i c a l ▪ (800) 426-5480 ▪ w w w .c m a f h .c o m。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
A New Induction Motor V/f Control Method Capable of High-Performance Regulation at Low Speeds Alfredo Mu˜n oz-Garc´ıa,Thomas A.Lipo,Fellow,IEEE,and Donald W.Novotny,Fellow,IEEEAbstract—A novel open-loop speed control method for in-duction motors that provides high output torque and nearly zero steady-state speed error at any frequency is presented. The control scheme is based on the popular constant volts per hertz(V/f)method using low-cost open-loop current sensors. Only stator current measurements are needed to compensate for both stator resistance drop and slip frequency.The scheme proposed fully compensates for the current–resistance(IR)voltage drop by vectorially modifying the stator voltage and keeping the magnitude of the statorflux constant,regardless of changes in frequency or load.A novel slip frequency compensation,based on a nonlinear torque–speed estimate,is also introduced.This method reduces the steady-state speed error to almost zero.It is also shown that a linear torque–speed approximation is a special case of the nonlinear estimate and that it leads to large speed errors for loads greater than rated.It is shown that,by using the proposed method,the speed can be accurately controlled down to,at least,1.2Hz with load torques of more than150% of rated value.Since the only machine parameter required, the stator resistance,is automatically measured at startup time, using the same pulsewidth modulated voltage-source inverter without additional hardware,the proposed drive also exhibits self-commissioning capability.Index Terms—Constant volts per hertz,induction machine,low speed,slip compensation.I.I NTRODUCTIONT HE operation of induction motors in the so-called con-stant volts per hertz(V/f)mode has been known for many decades,and its principle is well understood[1],[7].With the introduction of solid-state inverters,the constant V/f control became popular[2]–[4],and the great majority of variable-speed drives in operation today are of this type[5].However, since the introduction of vector control theory by Blaschke[6], almost all research has been concentrated in this area,and little has been published about constant V/f operation.Its practical application at low frequency is still challenging,due to thePaper IPCSD98–14,presented at the1997Industry Applications Society Annual Meeting,New Orleans,LA,October5–9,and approved for publication in the IEEE T RANSACTIONS ON I NDUSTRY A PPLICATIONS by the Industrial Drives Committee of the IEEE Industry Applications Society.This work was supported in part by the Wisconsin Electric Machines and Power Electronics Consortium(WEMPEC).Manuscript released for publication February25, 1998.A.Mu˜n oz-Garc´ıa is with the Department of Electrical and Computer Engineering,University of Wisconsin,Madison,WI53706-1691USA,on leave from the Technical University Santa Maria,Valpara´ıso,Chile.T.A.Lipo and D.W.Novotny are with the Department of Electrical and Computer Engineering,University of Wisconsin,Madison,WI53706-1691 USA.Publisher Item Identifier S0093-9994(98)04920-2.influence of the stator resistance and the necessary rotor slip to produce torque.In addition,the nonlinear behavior of the modern pulsewidth modulated voltage-source inverter(PWM-VSI)in the low voltage range[8]–[10]makes it difficult to use constant V/f drives at frequencies below3Hz[11].The simplest stator resistance compensation method consists of boosting the stator voltage by the magnitude of the cur-rent–resistance(IR)drop[12].Improved techniques using the in-phase component of the stator current and a compensation proportional to a slip signal have also been proposed[7].A vector compensation was proposed in[13],but it required both voltage and current sensors and accurate knowledge of machine inductances.More recently,a scalar control scheme was proposed[14].In this scheme,theflux magnitude is derived from the current estimation.In[15],using the dc-link voltage and current,bothflux and torque loops are introduced. Its use at low frequency is limited by theflux estimation.Also, the slip compensation was based on a linear torque–speed assumption which led to large steady-state errors in speed for high load torques.A linearized frequency compensation control based on an“ideal induction motor”was proposed in [16].In this paper,a new stator resistance and frequency com-pensation technique requiring minimum knowledge of the motor’s parameters is presented.The only measured quantity is the stator current.The stator resistance voltage drop is fully compensated for by vectorially adding it to the commanded voltage using both in-phase and quadrature components of the stator current.The frequency compensation is based on an estimation of the airgap power and a nonlinear relationship between slip frequency and airgap power.This method predicts the correct slip frequency for any load at any frequency. The proposed control scheme requires only nameplate data, the stator resistance value,and a reasonable estimation of the breakdown torque.The proposed method is validated by simulation and experimental results.It is shown that large torques are obtainable,even in the low speed range,with almost no steady-state error in speed.II.S TATOR R ESISTANCE C OMPENSATIONThe stator resistance compensation is based on keeping the statorflux-linkage magnitude constant and equal to its rated value.From the phasor diagram shown in Fig.1,it is easy to show that the magnitudeofFig.1.Induction motor steady-state equivalent circuit and phasor diagram.Definingis a constant defined by rated conditions,and thesubscriptand(4)where(5)where is the peak current andhas been replaced by the symbol to stressthat only real quantities are used.Although,by definition,the rms current and the powerfactor are steady-state quantities,the use of(3),(5),and(6)yields instantaneous measurements of both of them.This is avery important factor,since it gives continuous measurementsthat can be used for feedback purposes,allowing for betterdynamics in the control.An alternate form to obtain the powerfactor is to measure the time delay between the zero crossingsof the current and the voltage.This method,however,givespoor results for several reasons;first,the measured currentcontains high-frequency noise that makes it difficult to identifythe exact point of zero crossing,and second,the power factormeasurement can only be updated,at most,every1/6of acycle.These problems are eliminated by using(3),(5),and(6).Thefinal expression for the required stator voltage,includingonly instantaneously measured and commanded quantities,is(7)Equation(7)corresponds to a vector compensation of the IRdrop.Given the inherently positive feedback characteristic ofthe IR boost algorithm,it is necessary to stabilize the systemby introducing afirst-order lag in the feedback loop(low-passfilter).Since(7)contains both the IR boost and the base V/fratio,we only need to apply the lag to the boost componentof the algorithm;this is shown schematically in Fig.2.III.S LIP F REQUENCY C OMPENSATIONIn order to produce torque,an induction motor needsto develop slip.This means that the rotor only runs atsynchronous speed at no load,and,for any other condition,themechanical speed is reduced by the slip.At rated frequency,the slip is usually around3%,and its effect can be ignored.Forvariable-frequency operation,however,the slipMU ˜NOZ-GARCIA et al.:A NEW INDUCTION MOTOR V/f CONTROL METHOD815Fig.2.IR compensation including first-order lag.Fig.3.Slip compensation method.The gray area shows the error introduced by a linear compensation.by the linear approximation.The slip compensation proposed in this paper is based on the actual nonlinear torque–speed characteristic of the machine.For typical NEMA-B design induction motors operating at rated frequency,the stator resistance is much smaller than the total leakage reactance,and the electromagnetic torque is known to be [1](9)whereis the breakdown torque andis the number of poles,is the slip frequency,and is themechanical commanded frequency.Substituting (12)into (11)and solving for the slip frequency yieldsandand816IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS,VOL.34,NO.4,JULY/AUGUST1998Fig.4.Torque–speed curve.Linear and nonlinear torque approximations(the solid line corresponds to the actual curve).is not generally known,it certainly is afinite quantity and, for a typical NEMA B design,its value lies between1.5–3. Hence,the use of(13)provides a huge improvement over the linear approximation.To illustrate the difference between(13) and(14),actual and estimated torque–speed curves using both schemes are presented in Fig.4.A20%erroron(16)where(17)TABLE II NDUCTION M ACHINE DATAand substituting(17)into(16)yields(19)wheres,and the total control program execution time is approxi-mately100MU˜NOZ-GARCIA et al.:A NEW INDUCTION MOTOR V/f CONTROL METHOD817Fig.5.Advanced induction motor V/f control,including voltage boost and slip frequency compensationloops.Fig.6.Experimental setup.A.IR CompensationThe effectiveness of the stator resistance compensation algo-rithm was evaluated by measuring the resultant torque–speed characteristics at different frequencies and verifying that the slope of the curves remains constant.The simulated results are shown in Fig.7,and the exper-imental measurements are presented in Fig.8.An excellent response in both cases is clearly seen.The lower limit on the frequency used in the experimental part is due to the machine stalling at lower frequencies.B.Slip CompensationBoth the linear and nonlinear slip compensation techniques were simulated and tested in the laboratory.The speed range used in the experimental part was from1.2Hz(36r/min) to60Hz(1800r/min)for loads up to150%of rated value. The lower limit on the frequency was primarily imposed by the capability to accurately synthesize the commanded voltage with the PWM inverter.1)Steady-State Response:The simulation results are shown in Fig.9.As predicted,the linear slip compensation yields large speed errors for torques beyond rated value.For the nonlinear method,a20%error on the estimatedbreakdown Fig.7.IR compensation,steady-state model simulation results.Solid line:including IR compensation algorithm;dashed line:without IRcompensation. Fig.8.Speed response,including the IR compensation algorithm.Experi-mental and simulation results are overlapped.torque has been intentionally introduced.It can be seen that the technique is very insensitive to errors in this parameter. Fig.10shows the measured torque–speed curves using the nonlinear slip compensation.The measured magnitude of the stator currents for the same conditions are presented in Fig.11.818IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS,VOL.34,NO.4,JULY/AUGUST1998Fig.9.Speed response,including slip compensation.Simulation results.Solid line:nonlinear method;dashed line:linearapproximation.Fig.10.Steady-state speed response,including IR compensation and slip compensation.Experimental results.To illustrate the importance of the slip compensation method,measurements at 10Hz are presented in Table II.As shown,the nonlinear method gives nearly zero speed error,while the linear approximation yields almost a 6%error.2)Dynamic Behavior:Usually,a constant V/f drive is not used for high-performance applications,and its dynamic re-sponse is not of primary concern;however,all drives should exhibit a reasonable dynamic response and avoid instability problems.Simulation results showing the response to a rated torque change at 1.2Hz and to a ramp speed command are presented in Figs.12and 13.In the first case,the motor initially stalls after the load is applied,and after 1s,the drive recovers and reaches the final speed with zero steady-state error.The response to a ramp command shows a good dynamic behavior.Fig.14shows the experimental response to a rated torque at 7-Hz commanded frequency,and Fig.15shows the response at 2Hz.In both cases,the dynamic response isreasonablyFig.11.Steady-state stator current response,including IR and slip compen-sation.Experimental results.TABLE II M EASUREDS PEED R ESPONSEAT10Hzfast and very stable.Finally,Fig.16shows the acceleration from 0to 30Hz.The experimental results show the excellent response achieved with the proposed control method,even at extremely low frequencies.Also,the dynamic response indicates very good behavior over the whole frequency range.VI.S TATOR R ESISTANCE M EASUREMENTAs it was pointed out in Section I,the only machine parameter required to implement the control algorithm is the stator resistance.This parameter is measured during startup using the same PWM-VSI inverter.The stator resistance is measured by applying a dc volt-age between two of the stator phases and leaving the third one disconnected.The dc voltage is synthesized using the same PWM inverter and commanding a constant voltage.Bycommandingto one phase and to another,the line–line voltage contains a dccomponentplus high-frequency components starting at twice the switching frequency.The measurement procedure is as follows.After applying the test voltage,the measurement algorithm waits for approx-imately 0.6s before starting the current measurement routine;this is done to avoid the influence of transients during the measurement.After the waiting period,the current is sampled 4096times over a time interval of approximately 0.5s,and the average value is computed.The stator resistance is obtained by dividing the applied voltage by the current.MU ˜NOZ-GARCIA et al.:A NEW INDUCTION MOTOR V/f CONTROL METHOD819Fig.12.Simulated no-load start at 1.2Hz commanded frequency.Full load applied at t =3s.A 10%breakaway torque at zero speed is included.Top trace:rotor speed in revolutions per minute;middle trace:stator frequency in hertz;bottom trace:instantaneous phase stator current in per unit of ratedcurrent.Fig.13.Simulated response to a ramp command with full load.This procedure yields very good accuracy,with errors less than 2%.The accuracy of the method is basically defined by the accuracy of the current sensor and the quality oftheFig.14.Experimental rated torque manded frequency 7Hz.Speed error 0.27%.From top:stator current,commanded voltage (magnitude),speed,andtorque.Fig.15.Experimental rated torque manded frequency 2Hz.Speed error 3r/min.From top:stator current,rms current,commanded frequency,and torque.synthesized output voltage.In this case,the accuracy of the current sensors is fixed at 1%.The accuracy of the output voltage is guaranteed by using a dc-link voltage measurement and adjusting the valueof820IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS,VOL.34,NO.4,JULY/AUGUST1998Fig.16.Experimental acceleration from 0to 30Hz.From top:stator current,rms current,and commanded voltage(magnitude).Fig.17.Stator resistance measurement.From top:phase-a current,phase-a commanded voltage,and measurement flag (high means data acquisition).synthesis of a reduced output voltage is limited by the non-linear behavior of a PWM-VSI [8]–[10,[19],it is necessary to provide some means of compensation.The main effects that need to be compensated for are the dead time and the voltage drop across the switches.A detailed discussion of the compensation scheme used goes beyond the scope of this paper and will be presented in a future publication.However,it is important to mention that,in order to achieve a precise speed control in the low-frequency region,a voltage accuracy better than 1V is required.It is also important to point out that,since the actual blanking time varies with a device’s temperature and current,the resulting variation in turn-on and turnoff delays requires that the dead-time compensation must be implemented on-line.VIII.C ONCLUSIONSA new open-loop constant V/f control method has been presented.The influence of the slip regulation,too oftenneglected,has been studied in detail,and a new compensation method requiring knowledge of only the stator resistance has been proposed.The only measurement needed is the stator current,which is accomplished using a low-cost open-loop type of current transducer.Experimental and simulation results validate the effectiveness of the method and show that good open-loop speed regulation can be achieved.The proposed drive can be easily implemented in existing V/f drives by mod-ifying only the software.Since the only machine parameter needed for the control algorithm is the stator resistance,which is measured during startup using the same PWM inverter and control microprocessor,the system is well suited for operation with off-the-shelf motors,without needing a retuning of the control loops if the motor is replaced.Thus,the proposed drive also exhibits self-commissioning capability.R EFERENCES[1]P.L.Alger,Induction Machines ,2nd ed.New York:Gordon andBreach,1970.[2]R. A.Hamilton and G.R.Lezan,“Thyristor adjustable frequencypower supplies for hot strip mill run-out tables,”IEEE Trans.Ind.Gen.Applicat.,vol.IGA-3,pp.168–175,Mar./Apr.1967.[3]W.Slabiak and wson,“Precise control of a three-phase squirrel-cage induction motor using a practical cyclconverter,”IEEE Trans.Ind.Gen.Applicat.,vol.IGA-2,pp.274–280,July/Aug.1966.[4]W.Shepherd and J.Stanway,“An experimental closed-loop vari-able speed drive incorporating a thyristor driven induction motor,”IEEE Trans.Ind.Gen.Applicat.,vol.IGA-3,pp.559–565,Nov./Dec.1967.[5] B.K.Bose,Ed.,Power Electronics and Variable Frequency Drives .New York:IEEE Press,1996.[6] F.Blaschke,‘The principle of field orientation as applied to the newtransvektor closed-loop control system for rotating-field machines,”Siemens Rev.,vol.34,pp.217–220,1972.[7] A.Abbondanti,“Method of flux control in induction motors driven byvariable frequency,variable voltage supplies,”in Proc.IEEE-IAS Int.Semi-Annual Power Conversion Conf.,1977,pp.177–184.[8]Y.Murai,T.Watanabe,and H.Iwasaki,“Waveform distortion andcorrection circuit for PWM inverters with switching lag-times,”IEEE Trans.Ind.Applicat.,vol.IA-23,pp.881–886,Sept./Oct.1987.[9]J.W.Choi,S.I.Yong,and S.K.Sul,“Inverter output voltage synthesisusing novel dead time compensation,”IEEE Trans.Ind.Applicat.,vol.31,pp.1001–1008,Sept./Oct.1995.[10]R.Sepe and ng,“Inverter nonlinearities and discrete-time vectorcurrent control,”IEEE Trans.Ind.Applicat.,vol.30,pp.62–70,Jan./Feb.1994.[11]K.Koga,R.Ueda,and T.Sonoda,“Achievement of high performancesfor general purpose inverter drive induction motor system,”in Conf.Rec.IEEE-IAS Annu.Meeting ,1989,pp.415–425.[12] F.A.Stich,“Transistor inverter motor drive having voltage boost at lowspeeds,”U.S.Patent 3971972,1976.[13] A.Abbondanti,“Flux control system for controlled induction motors,”U.S.Patent 3909687,1975.[14]T.C.Green and B.W.Williams,“Control of induction motor usingphase current feedback derived from the DC link,”in Proc.EPE’89,1989,vol.III,pp.1391–1396.[15]Y.Xue,X.Xu,T.G.Habetler,and D.M.Divan,“A low cost statororiented voltage source variable speed drive,”in Conf.Rec.IEEE-IAS Annu.Meeting ,1990,pp.410–415.[16]K.Koga,R.Ueda,and T.Sonoda,“Constitution of V/f control forreducing the steady state speed error to zero in induction motor drive system,”in Conf.Rec.IEEE-IAS Annu.Meeting ,1990,pp.639–646.[17] D.W.Novotny and T.A.Lipo,Vector Control and Dynamics of ACDrives .Oxford,U.K.:Clarendon,1996.[18]S.Nishikata and D.W.Novotny,“Efficiency considerations for lowfrequency operation of induction motors,”in Conf.Rec.IEEE-IAS Annu.Meeting ,1988,pp.91–96.[19]J.Lee,T.Takeshita,and N.Matsui,“Optimized stator flux orientedsensorless drives of IM in low-speed performance,”in Conf.Rec.IEEE-IAS Annu.Meeting ,1996,pp.250–256.MU˜NOZ-GARCIA et al.:A NEW INDUCTION MOTOR V/f CONTROL METHOD821Alfredo Mu˜noz-Garc´ıa was born in Valpara´ıso,Chile.He received the B.S.degree in electrical engi-neering in1981from the Technical University SantaMaria,Valpara´ıso,Chile,and the M.S.degree inelectrical engineering in1995from the University ofWisconsin,Madison,where he is currently workingtowards the Ph.D.degree.From1981to1986,he was with SchlumbergerOverseas.In1987,he became a full-time Lecturerat the Technical University Santa Maria,from wherehe is currently on leave as a Research Assistant at the University of Wisconsin.He has been involved in several research projects in the areas of variable-frequency drives and power electronics.He was a Fulbright Fellow from1993to1995.His main research interests includeelectric machines,ac drives,and powerelectronics.Thomas A.Lipo(M’64–SM’71–F’87)is a nativeof Milwaukee,WI.From1969to1979,he was an Electrical Engi-neer in the Power Electronics Laboratory,CorporateResearch and Development,General Electric Com-pany,Schenectady NY.He became a Professor ofElectrical Engineering at Purdue University,WestLafayette,IN,in1979and,in1981,he joinedthe University of Wisconsin,Madison,in the samecapacity,where he is presently the W.W.GraingerProfessor for Power Electronics and Electrical Ma-chines.Dr.Lipo has received the Outstanding Achievement Award from the IEEE Industry Applications Society,the William E.Newell Award of the IEEE Power Electronics Society,and the1995Nicola Tesla IEEE Field Award from the IEEE Power Engineering Society for his work.Over the past30 years,he has served the IEEE in numerous capacities,including President of the IEEE Industry ApplicationsSociety.Donald W.Novotny(M’62–SM’77–F’87)receivedthe B.S.and M.S.degrees in electrical engineeringfrom the Illinois Institute of Technology,Chicago,and the Ph.D.degree from the University of Wiscon-sin,Madison,in1956,1957,and1961,respectively.Since1961,he has been a member of the facultyat the University of Wisconsin,Madison,wherehe is currently an Emeritus Professor.Prior toretirement in1996,he was Grainger Professor ofPower Electronics and Co-Director of the Wis-consin Electric Machines and Power Consortium (WEMPEC),an educational and research support organization with over50 industry sponsors.He served as Chairman of the Electrical and Computer Engineering Department from1976to1980and as an Associate Director of the University–Industry Research Program from1972to1974and from 1980to1993.He has been active as a Consultant to many organizations and has also been a Visiting Professor at Montana State University,the Technical University of Eindhoven,Eindhoven,The Netherlands,the Catholic University of Leuven,Leuven,Belgium,and a Fulbright Lecturer at the University of Ghent,Ghent,Belgium.He has published more than100technical articles on electric machines,variable-frequency drives,and power electronic control of industrial systems.Dr.Novotny is a member of the American Society of Engineering Ed-ucation,Sigma Xi,Eta Kappa Nu,and Tau Beta Pi and is a Registered Professional Engineer in Wisconsin.He is the recipient of nine Prize Paper Awards from the IEEE Industry Applications Society.。