A01_PC-AXM_STANDARD_EXAMPLE SPEED教程

SPEED TUTORIAL A0124 July 2010PC-AXM Axial-Flux Motor — Standard Axial-Flux ExampleObjectivesTo introduce the basic operations of the PC-AXM program by loading and calculating a standard example of an axial-flux machine. The tutorial will help you to become familiar with the geometry, windings, control and performance of axial-flux machines. It explains the various forms of input data through the OUTLINE EDITOR and the TEMPLATE EDITOR, and the extensive output data in the DESIGN SHEET, the graphs, and the phasor diagram. It also explains the difference between static design (forced-current operation) and dynamic design (performance calculations including inverter simulation).BackgroundAlthough axial-flux machines are not as common as radial-flux machines, they are of interest to many companies because of the flat configuration (short axial length and large diameter). They have naturally high inertia and suitability for low-speed operation, and they can be used as motors or generators.PC-AXM covers several types of axial-flux machine with different configurations of rotating magnets, and several types of stator.PC-AXM deals not only with true axial-flux machines but also with machines having gramme-type or toroidal stators. It also covers double-airgap machines with radial airgap flux, with gramme-type and other types of segmented stators, which are grouped together as “Ring-Arc” machines.PC-AXM also covers the claw-pole machine in both permanent-magnet and wound-field versions.Knowledge required, and Further ReadingBasic theory of brushless permanent-magnet machines and synchronous machines. Basic knowledge of electromagnetic theory. Readers familiar with PC-BDC will find many of the same concepts and methods in PC-AXM.The PC-AXM Reference Manual is the place to find detailed information on methods and parameters.For further reading on the theory, SPEED's Electric Machines is recommended, especially chapter 2 (referred to as SEM-2) ; and Design of Brushless Permanent-Magnet Machines by J.R. Hendershot and T.J.E. Miller, published in 2010 by Motor Design Books LLC. Also recommended is Axial Flux Permanent Magnet Brushless Machines by J.F. Gieras, R.-J. Wang and M.J. Kamper, published by Kluwer Academic Publishers in 2004.For general operations of SPEED software (including the materials databases), please see the WinSPEED manual. The PC-FEA manual may also be of interest for the limited number of finite-element GoFERs available with PC-AXM.Contents1Getting started (1)1.1Loading an example (1)1.2Selecting materials (3)1.3Help (3)1.4The template editor (4)2Analysis — Static and Dynamic design calculations (5)2.1Static design (5)2.2Dynamic design (6)2.3The Design sheet (7)2.4Torque/speed characteristic (9)2.5Phasor Diagram (10)3Where to go from here (10)Fonts and symbolsPC-AXM parameters are in boldface, while values are written in normal font, e.g. RPM' 6000. Menu items and operations are in boldface non-serif font, e.g. File | New.Certain functions and windows in PC-AXM are denoted in small caps, e.g., OUTLINE EDITOR.Fig. 1Selecting a standard example usingFile | NewFig. 2O UTLINE EDITOR — Rotor = Sector1Getting started 1.1Loading an exampleFrom the File|New menu, select the first example, Stator = Slotted; Rotor = Sector-Magnet . This example can also be obtained with the [Alt+1] short-cut. See Fig. 1.The OUTLINE EDITOR opens with a view of the rotor, Fig. 2. 1Rotor is only one of several views. Select the other tabbed pages, Stator , Side , Shaft , BothRS to see different views of the machine. All views except Side are taken along the axis of rotation.The standard example has 8 rotor poles, and the magnet shape is Rotor = Sector . Other magnet shapes are available; click Rotor to see the PlloGram and Disc shapes.Fig. 3Stator view with Stator =SlottedFig. 3 shows the Stator view. Two coils are displayed : NCD = 2. The OUTLINE EDITOR shows the mechanical disposition of coils but PC-AXM does not have a WINDING EDITOR ; consequently the number of coils per pole and the winding parameters must be chosen sensibly.In this standard example there are 12 slots, so the number of slots per pole is 1@5. Each coil is wound on one “tooth”, that is, in two adjacent slots. With 3 phases there are 12 coils and 4 coils per phase, so there are two coil-sides per slot. The two coils shown in Fig. 3 belong to different phases.The dimensions of the rotor and stator can be edited simply by changing the values in the appropriate fields. Changes should be made with reference to the diagrams in the PC-AXM reference manual. It goes without saying that changes should be made with care. For this tutorial, it is advisable to keep to the standard dimensions.Fig. 5Selecting materials1.2Selecting materialsUsing Data|Materials or [Ctrl+M ], as in Fig. 5, select a high-energy magnet such as "NeIGT 30H", and a low-loss steel such as "M19 29 gage". Save the file.The MATERIAL DATABASES for steels and magnets are the same as those used with all the other SPEED programs. The preparation of material data is important, and it is described in the WinSPEED manual.1.3HelpThe documentation of all SPEED software is primarily designed for printing, but it is available on the Help menu in the form of PDF files.2 The Theory manual is SPEED's Electric Machines . The Reference manual is the PC-AXM program reference manual, where all the details of parameters and functions can be found, as well as all the reference diagrams containing dimensions and configurations.Help | Manuals | Tutorials accesses the available tutorials for the program, while Help | Manuals | Topics provides most of the training-course slides. These contain many of the important diagrams from the Reference manual, and they are often useful as a quick way of displaying these diagrams on the computer screen.Fig. 6T EMPLATE EDITOR ; Control page1.4The template editorThe TEMPLATE EDITOR is accessed using Data | Template or [Ctrl+3]. It contains all the mechanical and electrical data as well as the control and thermal data, separated into sections on separate pages. The Control page is shown in Fig. 6.The Control page concerns the type of drive and the PWM control scheme. The speed and supply voltage can also be found on this page.In the standard example a sinewave inverter is used (Drive = Sine), with a PWM control defined by the parameter Sw_Ctl , which is set to dq_VV_CR . This controller is also found in PC-BDC , but in PC-AXM it is the only option with sinewave drive. It is extremely simple to control, since it has only one main parameter, the set-point or reference current ISP . ISP is the peak value of the desired sinewave line current, and it represents the reference current or control setpoint current.The dq_VV_CR controller requires a current-sensor with a sufficiently high sampling frequency, and the simplest way to ensure that is to set fCspec = ISChop12. The integration step-length adjustment should be left equal to ISLA = 64.The PWM control in dq_VV_CR is quite similar to the switching table in “direct torque control” (DTC).The main difference between dq_VV_CR and DTC is that dq_VV_CR is simply a current regulator with fixed logic, whereas DTC has a more sophisticated algorithm for controlling the inverter output voltage in the pursuit of a reference torque .The parameters should be reset to their standard settings before proceeding with the calculation.Fig. 7Static design waveforms of current, EMF and torque2Analysis — Static and Dynamic design calculationsPC-AXM has two main calculations, Static design and Dynamic design , both of which are accessed from the Analysis menu. Both of them are steady-state calculations at a fixed speed (RPM ). The torque/speed characteristic can also be calculated as a series of Static or Dynamic design calculations.2.1Static designIf Drive = Square or Sine , Static design is an idealized calculation in which the current waveforms are forced to have an ideal shape with peak value ISP in the lines. If Drive = AC Volt, the terminal voltage is forced to be a pure sinewave; in this case, the solution is by phasor analysis and so the current is also assumed to be sinusoidal.With Drive = Square, run Analysis | Static design , [Ctrl+2]. You will see Results appearing on the main menu.Select Results | Simulation graphs | Current, EMF and Torque , [Ctrl+G ]. See Fig. 7.It is always advisable to check the waveforms first. We can see in Fig. 7 the three line currents, the three line-line EMF s, and the torque.The phase relationships between these waveforms are important. In this example the EMF waveform is not the ideal trapezoid of the perfect “squarewave” motor. Consequently the torque waveform has a pulsation at six times the fundamental rotation frequency.The waveform display can be changed in many useful ways. Using Graph | Probe or [F7], you can select the line or phase waveforms, and various combinations. It is also possible to display the terminal voltage instead of the EMF waveform.[F6] indexes the display through four different colour schemes to assist in viewing under different lighting conditions. These schemes and many other aspects of the display can be edited using Graph | Options , [F8]. The data can be extracted in tabular form using Graph | Save graph data. The simplest way to save graph data is to Copy [Ctrl+C ] and paste into a spreadsheet such as Quattro Pro®.Fig. 8Dynamic design waveforms of current, EMF and torque2.2Dynamic designWith Drive = Square, run Analysis | Dynamic design , [Ctrl+D ]. You will see Results appearing on the main menu.Again select Results | Simulation graphs | Current, EMF and Torque , [Ctrl+G ]. See Fig. 8.Dynamic design includes the simulation of the detailed operation of the inverter and its PWM control scheme, so the high-frequency switching or “chopping” is evident in the current waveform (but not, of course, in the EMF ). The six-times-per-revolution torque ripple is again evident, and there is a high-frequency component caused by the current ripple at the switching frequency. The torque waveform shows the electromagnetic torque, and the inertia tends to screen most of the high-frequency ripple from the shaft torque.Also in Fig. 8 it can be seen that the “probe” [F7] has been set to show a different combination of waveforms: the principal phase and line waveforms. In the case of the currents, the phase and line currents are identical because this example has a wye connection. In the case of the EMF s, the fundamental of the line EMF leads that of the phase EMF by 30E . The fundamentals can be displayed by pressing the [F ] key. Also a legend can be displayed by pressing the [L ] key.Unlike the Static design waveforms, the Dynamic design waveforms are very sensitive to the speed and the available supply voltage. Changes in speed, voltage, turns, etc. should be made in small steps, and it is advisable to keep an eye on the waveforms at all times. The same applies to changes in the inverter parameters, particularly the set-point current ISP and any phase-advance angle.2.3The Design sheet6 Performance [Dynamic design]:----------------------------------------------Drive Square Vs 150.0000 V RPM 1000.0000 rpmOpMode Motoring Tshaft 12.6997 Nm Pshaft 1330.8793 WEffcy 90.8556 % TempRise 0.0000 °C Pelec 1464.8293 WILpk 14.8178 A ILmean 9.2100 A ILrms 11.2712 AIWpk 14.8178 A IWmean 9.2100 A IWrms 11.2712 AEWpk 69.3730 V EWmean 40.7039 V EWrms 44.1873 VELpk 104.1773 V ELmean 65.7133 V ELrms 76.5347 VVWpk 0.0000 V VWmean 0.0000 V VWrms 0.0000 VVLpk 0.0000 V VLmean 0.0000 V VLrms 0.0000 VRMS fundamental values with waveform phase angles..IL1 10.7739 A phIL1 -0.4928 ° Ref.Wfm. ILAIph1 10.7739 A phIph1 -0.4928 °Eph1 43.6342 V phEph1 0.0000 °EL1 75.5767 V phEL1 30.0000 °Vph1 0.0000 V phVph1 90.0000 °VL1 0.0000 V phVL1 0.0000 °phi1 5184.8553 ° Cosphi1 -8.601E-03 TruePF 0.0000Phasor components..Ed1 0.0000 V Eq1 43.6342 V Ref. Eq1Id1 0.0000 A Iq1 0.0000 A Th0 0.0000 °Vd1 0.0000 V Vq1 0.0000 V delta_CF 0.0000 °RId1 0.0000 V RIq1 0.0000 V RIpu 0.0000 p.u.jXdId1 0.0000 V jXqIq1 0.0000 V Psi1Md 147.3173 mVsPsid1 0.0000 mVs Psiq1 0.0000 mVs Psi1 0.0000 mVsCurrent density..Jrms 14.3510 A/mm²Losses..WTotal 103.3231 W WCu 72.6962 W WFe 30.6269 WWWF 0.0000 W WFric 0.0000 W WMagnet 0.0000 WWFeST 13.4867 W WFeSY 17.1402 WTorque analysis..Tshaft 12.6997 Nm Tem 13.0014 Nm Tloop 13.0014 NmTei 13.0014 Nm Trx 0.0000 Nm Tmech 0.2925 NmTsh_PPR 8.6197 Nm Tsh_max 14.2262 Nm Tsh_min 5.6065 NmPower semiconductor devices..IQ1pk 15.4857 A IQ1Mean 3.9033 A IQ1RMS 7.3559 AIQ2pk 15.4857 A IQ2Mean 3.9033 A IQ2RMS 7.3559 AID1pk 14.8363 A ID1Mean 0.7014 A ID1RMS 3.1064 AID2pk 15.4435 A ID2Mean 0.7014 A ID2RMS 3.1064 AIDC_P 9.7824 A IDC_W 9.6055 AWQ1 0.0000 W WQ2 0.0000 W WConv 2.5252 WWD1 0.4209 W WD2 0.4209 W WSwitch 0.0000 WWRac 0.0000 W WR_s 0.0000 W VR_s 0.0000 VThe DESIGN SHEET contains all the numerical data calculated by PC-AXM at the particular operating point shown in the waveform graphs. It also includes all the input parameters from the OUTLINE EDITOR and the TEMPLATE EDITOR, generally in a different style or colour to distinguish them from output parameters. The example shown here is of the Performance section, in which most of the parameters are output parameters.Fig. 9Using a CUSTOM EDITOR with the DESIGN SHEET In the course of design calculations the DESIGN SHEET section 6 will be visited many times, and it can conveniently be displayed with the Performance section at the top of the computer screen by pressing the [6] key. Other numbered sections can be positioned in the same way, and the inductance section by means of the [L ] key.The Performance section is subdivided, with the main parameters of torque, power and efficiency displayed first. Next, the peak, mean and RMS values of the main waveforms (current, EMF and voltage)are displayed.A more detailed analysis of the waveforms follows under the heading RMS fundamental values with waveform phase angles.. These parameters are derived directly from the waveform graphs.The Phasor components.. section presents a summary of the same waveform data derived from the phasor diagram, which can be viewed using Results | Phasor diagram , [Ctrl+A ]. In many cases the currents and/or EMF s and voltages are not sinusoidal, and the phasor analysis then refers only to the fundamental components.The Current density.. and Losses.. sections are essentially self-explanatory, while the Torque analysis.. section provides information about torque components and ripple.The Performance data includes an analysis of the peak, mean and RMS currents in all the power semiconductor devices of the inverter, together with their conduction losses and switching losses.Design sheet facilitiesThe DESIGN SHEET can be saved to a text file or RTF file for incorporation in other programs such as WordPerfect®. On the main menu, use Design Sheet | Save Design Sheet .The appearance of the DESIGN SHEET can be altered using Design Sheet | Options , [F8].A tabbed-page version of the DESIGN SHEET is available, and CUSTOM OUTPUT windows can be made up using Results | Custom Output , [Ctrl+Shift+4]. (Instructions can be found in the WinSPEED manual).Good practiceIt is a good idea to keep the DESIGN SHEET open while repeating calculations, so that changes in the performance can be seen immediately. An example is shown in Fig. 9, where a CUSTOM EDITOR is shown at the right-hand side. It is often possible to do a long series of calculations without moving away from this window: changes are made in the CUSTOM EDITOR , and the performance is re-calculated using the[Ctrl+2] or [Ctrl+D ] short-cut key. The DESIGN SHEET is updated immediately. Similar displays can be set up with the waveform graphs or the OUTLINE EDITOR , and further developed using CUSTOM OUTPUT windows.Fig. 10Torque/speed characteristic2.4Torque/speed characteristicThe torque/speed characteristic can be calculated using Analysis | Torque/Speed . An example is shown in Fig. 10.The torque/speed calculation always uses Dynamic design , including full simulation of the inverter.Consequently the current regulator can become saturated at high speed, and the machine can even switch from motoring to generating. It is advisable to check a few points using the steady-state calculation [Ctrl+D ] before launching into the automatic torque/speed calculation.The display in Fig. 10 can be changed in a variety of ways. Torque can be plotted on the x - or the y -axis,and conversely speed on the y - or x -axis. Other quantities such as efficiency and power can be plotted,and the scales can be made automatic or definite. When more than one graph is plotted on the sheet,Per-unit axes are used, with the base quantities defined in the respective Scale fields.Fig. 11Phasor diagram2.5Phasor DiagramThe phasor diagram is available after a Static design or Dynamic design calculation, from the Results menu, Results | Phasor Diagram , [Ctrl+A ]. When the current and/or voltage waveforms are not sinusoidal, the fundamental harmonic components are used, and these are obtained from the time waveforms by Fourier analysis. An example is shown in Fig. 11.The display of the phasor diagram can be altered using the Argand menu when the phasor diagram window is active. In particular, the values of the phasors in the box on the left-hand side can be displayed in polar or cartesian coordinates, and they can be displayed or hidden by means of the check-boxes in the tree structure.The phasor diagram is always plotted with the d -axis horizontal. The magnet flux-linkage phasor Psi1Md lies on this axis. The generated EMF Eq1 is always represented on the vertical q -axis at 90E .When Drive = Sine or Square , the convention used in the phasor diagram is that motoring current is positive. The same is true when Drive = AC Vol t and Sw_Ctl = Motor ; but if Sw_Ctl = Generator ,generating current is positive and the order of the phasors changes. All the voltage-drop phasors then change sign, and the torque angle delta is positive when the EMF leads the terminal voltage. (In the motoring convention, delta is positive when the terminal voltage leads the EMF ).The electrical parameters in the phasor diagram are reproduced (with the same names) in the DESIGN SHEET , in section 6.3Where to go from hereThis tutorial has covered only one simple example of an axial-flux machine, providing only a brief coverage of the basic program features.For further examples including more advanced usage of PC-AXM , please use the additional tutorials.TJEM T40 — 13:22:53 Sun 25-Jul-10 — E:\MAN\Tutor\A01\A01_Axial_Flux_Standard_Example.wpdEnd-notes1. The opening window can be either the OUTLINE EDITOR or the TEMPLATE EDITOR; see Options |General | Initial View.2. The on-line Help in standard Windows format is very sparse in SPEED, because of our long-standing emphasis on printed manuals.。