电力电子外文文献翻译
电力电子英文文献2
IT champions drive integration to narrow the expertise gap. integration sottware Information technology (IT) Network integration Set implementation and maintenance policies, IT compliance, portai strategies, etc. Demand response programs and smart-grid applications Cloud computingsoftware as a service Growing convergence Source: Frost & Sullivan
ROAM is the total streetlight solution. • Reduces energy costs • Reduces maintenance costs
Understanding lighting controls.
Lighting control can be defined as hardware — and software — systems that regulate the intensity level of the light output in response to a command or action. Today's lighting controls fit into four main categories, according to their size and function: 1. Distributed networked systems offering total lighting control management. 2. Scalable panel systems using lowvoltage, mechanically held, single- and double-pole latching relays. 3. Architectural/commercial control systems handling a variety of control applications and using input devices that vary from keypads to touchscreen controllers. 4. Networked devices and wall box dimmers. In aggregate, this equipment can provide occupancy/vacancy control, daylight harvesting, time scheduling.
电气英文文献+翻译
POWER SUPPLY AND DISTRIBUTION SYSTEMABSTRACTThe basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, allcostumers expect to pay the lowest price for the highest reliability, but don't consider that it's self-contradictory in the co-existence of economy and reliable.To improve the reliability of the power supply network, we must increase the investment cost of the network construction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic,between the investment and the loss by calculating the investment on power net and the loss brought from power-off.KEYWARDS:power supply and distribution,power distribution reliability,reactive compensation,load distributionTEXTThe revolution of electric power system has brought a new big round construction,which is pushing the greater revolution of electric power technique along with the application of new technique and advanced equipment. Especially, the combination of the information technique and electric power technique, to great ex- tent, has improved reliability on electric quality and electric supply. The technical development decreases the cost on electric construction and drives innovation of electric network. On the basis of national and internatio- nal advanced electric knowledge, the dissertation introduces the research hotspot for present electric power sy- etem as following.Firstly, This dissertation introduces the building condition of distribution automation(DA), and brings forward two typical construction modes on DA construction, integrative mode and fission mode .It emphasize the DA structure under the condition of the fission mode and presents the system configuration, the main station scheme, the feeder scheme, the optimized communication scheme etc., which is for DA research reference.Secondly, as for the (DA) trouble measurement, position, isolation and resume, This dissertation analyzes the changes of pressure and current for line problem, gets math equation by educing phase short circuit and problem position under the condition of single-phase and works out equation and several parameter s U& , s I& and e I& table on problem . It brings out optimized isolation and resume plan, realizes auto isolation and network reconstruction, reduces the power off range and time and improves the reliability of electric power supply through problem self- diagnoses and self-analysis. It also introduces software flow and use for problem judgement and sets a model on network reconstruction and computer flow.Thirdly, electricity system state is estimated to be one of the key techniques in DA realization. The dissertation recommends the resolvent of bad measurement data and structure mistake on the ground of describing state estimate way. It also advances a practical test and judging way on topology mistake in state estimate about bad data test and abnormity in state estimate as well as the problem and effect on bad data from state measure to state estimate .As for real time monitor and control problem, the dissertation introduces a new way to solve them by electricity break and exceptional analysis, and the way has been tested in Weifang DA.Fourthly, about the difficulty for building the model of load forecasting, big parameter scatter limit and something concerned, the dissertation introduces some parameters, eg.weather factor, date type and social environment effect based on analysis of routine load forecasting and means. It presents the way for electricity load forecasting founded on neural network(ANN),which has been tested it’s validity by example and made to be good practical effect.Fifthly, concerning the lack of concordant wave on preve nting concordant wave and non-power compensation and non-continuity on compensation, there is a topology structure of PWM main circuit and nonpower theory on active filter the waves technique and builds flat proof on the ground of Saber Designer and proves to be practical. Meanwhile, it analyzes and designs the way of non-power need of electric network tre- nds and decreasing line loss combined with DA, which have been tested its objective economic benefit throu- gh counting example.Sixthly, not only do the dissertation design a way founded on the magrginal electric price fitted to our present national electric power market with regards to future trends of electric power market in China and fair trade under the government surveillance, that is group competitio n in short-term trade under the way of grouped price and quantity harmony, but also puts forward combination arithmetic, math model of trading plan and safty economical restriction. It can solve the original contradiction between medium and long term contract price and short term competitive price with improvement on competitive percentage and cut down the unfair income difference of electric factory, at the same time, it can optimize the electric limit for all electric factories and reduce the total purchase charge of electric power from burthen curve of whole electric market network.The distribution network is an important link among the power system. Its neutral grounding mode and operation connects security and stability of the power system directly. At the same time, the problem about neutral grounding is associated with national conditions, natural environment, device fabrication and operation. For example, the activity situation of the thunder and lightning, insulating structure and the peripheral interference will influence the choice of neutral grounding mode Conversely, neutral grounding mode affects design, operation, debugs and developing. Generally in the system higher in grade in the voltage, the insulating expenses account for more sizable proportion at the total price of the equipment. It is very remarkable to bring the economic benefits by reducing the insulating level. Usually such system adopt the neutral directly grounding and adopt the autoreclosing to guarantee power supply reliability. On the contrary, the system which is lower in the voltage adopts neutral none grounding to raise power supply reliability. So it is an important subject to make use of new- type earth device to apply tothe distribution network under considering the situation in such factors of various fields as power supply reliability, safety factor, over-voltage factor, the choice of relay protection, investment cost, etc.The main work of this paper is to research and choice the neutral grounding mode of the l0kV distribution network. The neutral grounding mode of the l0kV network mainly adopts none grounding, grounding by arc suppressing coil, grounding by reactance grounding and directly grounding. The best grounding mode is confirmed through the technology comparison. It can help the network run in safety and limit the earth electric arc by using auto-tracking compensate device and using the line protection with the detection of the sensitive small ground current. The paper introduces and analyzes the characteristic of all kind of grounding modes about l0kV network at first. With the comparison with technological and economy, the conclusion is drawn that the improved arc suppressing coil grounding mode shows a very big development potential.Then, this paper researches and introduces some operation characteristics of the arc suppressing coil grounding mode of the l0kV distribution network. And then the paper put emphasis on how to extinguish the earth electric arc effectively by utilizing the resonance principle. This paper combines the development of domestic and international technology and innovative achievement, and introduces the computer earth protection and autotracking compensate device. It proves that the improved arc suppressing coil grounding mode have better operation characteristics in power supply reliability, personal security, security of equipment and interference of communication. The application of the arc suppressing coil grounding mode is also researched in this paper.Finally, the paper summarizes this topic research. As a result of the domination of the arc suppressing coil grounding mode, it should be more popularized and applied in the distribution network in the future.The way of thinking, project and conclusions in this thesis have effect on the research to choose the neutral grounding mode not only in I0kV distribution network but also in other power system..The basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, all costumers expect to pay the lowest price for the highest reliability, but don't consider that it's self-contradictory in the co-existence of economy and reliable. To improve the reliability of the power supply network, we must increase the investment cost of the network con- struction But, if the cost that improve the reliability of the networkconstruction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic, between the investment and the loss by calculating the investment on power net and the loss brought from power-off. The thesis analyses on the economic and the reliable of the various line modes, according to the characteristics various line modes existed in the electric distribution net in foshan..First, the thesis introduces as the different line modes in the l0kV electric distribution net and in some foreign countries. Making it clear tow to conduct analyzing on the line mode of the electric distribution net, and telling us how important and necessary that analyses are.Second, it turns to the necessity of calculating the number of optimization subsection, elaborating how it influences on the economy and reliability. Then by building up the calculation mode of the number of optimization subsection it introduces different power supply projects on the different line modes in brief. Third, it carries on the calculation and analyses towards the reliability and economy of the different line modes of electric distribution net, describing drafts according by the calculation. Then it makes analysis and discussion on the number of optimization subsection.At last, the article make conclusion on the economy and reliability of different line modes, as well as, its application situation. Accordion to the actual circumstance, the thesis puts forward the beneficial suggestion on the programming and construction of the l0kV electric distribution net in all areas in foshan. Providing the basic theories and beneficial guideline for the programming design of the lOkV electric distribution net and building up a solid net, reasonable layout, qualified safe and efficiently-worked electric distribution net.References[1] Wencheng Su. Factories power supply [M]. Machinery Industry Publishing House. 1999.9[2] Jiecai Liu. Factories power supply design guidance [M]. Machinery Industry Publishing House.1999.12[3] Power supply and distribution system design specifications[S].China plans Press. 1996[4] Low-voltage distribution design specifications [S].China plans Press. 1996.6供配电系统摘要电力系统的基本功能是向用户输送电能。
电动汽车电子技术中英文对照外文翻译文献
(文档含英文原文和中文翻译)中英文资料外文翻译原文:As the world energy crisis, and the war and the energy consumption of oil -- and are full of energy, in one day, someday it will disappear without a trace. Oil is not in resources. So in oil consumption must be clean before finding a replacement. With the development of science and technology the progress ofthe society, people invented the electric car. Electric cars will become the most ideal of transportation.In the development of world each aspect is fruitful, especially with the automobile electronic technology and computer and rapid development of the information age. The electronic control technology in the car on a wide range of applications, the application of the electronic device, cars, and electronic technology not only to improve and enhance the quality and the traditional automobile electrical performance, but also improve the automobile fuel economy, performance, reliability and emissions purification. Widely used in automobile electronic products not only reduces the cost and reduce the complexity of the maintenance. From the fuel injection engine ignition devices, air control and emission control and fault diagnosis to the body auxiliary devices are generally used in electronic control technology, auto development mainly electromechanical integration. Widely used in automotive electronic control ignition system mainly electronic control fuel injection system, electronic control ignition system, electronic control automatic transmission, electronic control (ABS/ASR) control system,electronic control suspension system, electronic control power steering system, vehicle dynamic control system, the airbag systems, active belt system, electronic control system and the automatic air-conditioning and GPS navigation system etc. With the system response, the use function of quick car, high reliability, guarantees of engine power and reduce fuel consumption and emission regulations meet standards.The car is essential to modern traffic tools. And electric cars bring us infinite joy will give us the physical and mental relaxation. Take for example, automatic transmission in road, can not on the clutch, can achieve automatic shift and engine flameout, not so effective improve the driving convenience lighten the fatigue strength. Automatic transmission consists mainly of hydraulic torque converter, gear transmission, pump, hydraulic control system, electronic control system and oil cooling system, etc. The electronic control of suspension is mainly used to cushion the impact of the body and the road to reduce vibration that car getting smooth-going andstability. When the vehicle in the car when the road uneven road can according to automatically adjust the height. When the car ratio of height, low set to gas or oil cylinder filling or oil. If is opposite, gas or diarrhea. To ensure and improve the level of driving cars driving stability. Variable force power steering system can significantly change the driver for the work efficiency and the state, so widely used in electric cars. VDC to vehicle performance has important function it can according to the need of active braking to change the wheels of the car, car motions of state and optimum control performance, and increased automobile adhesion, controlling and stability. Besides these, appear beyond 4WS 4WD electric cars can greatly improve the performance of the value and ascending simultaneously. ABS braking distance is reduced and can keep turning skills effectively improve the stability of the directions simultaneously reduce tyre wear. The airbag appear in large programs protected the driver and passenger's safety, and greatly reduce automobile in collision of drivers and passengers in the buffer, to protect the safety of life.Intelligent electronic technology in the bus to promote safe driving and that the other functions. The realization of automatic driving through various sensors. Except some smart cars equipped with multiple outside sensors can fully perception of information and traffic facilities and to judge whether the vehicles and drivers in danger, has the independent pathfinding, navigation, avoid bump, no parking fees etc. Function. Effectively improve the safe transport of manipulation, reduce the pilot fatigue, improve passenger comfort. Of course battery electric vehicle is the key, the electric car battery mainly has: the use of lead-acid batteries, nickel cadmium battery, the battery, sodium sulfide sodium sulfide lithium battery, the battery, the battery, the flywheel zinc - air fuel cell and solar battery, the battery. In many kind of cells, the fuel cell is by far the most want to solve the problem of energy shortage car. Fuel cells have high pollution characteristics, different from other battery, the battery, need not only external constantly supply of fuel and electricity can continuously steadily. Fuel cell vehicles (FCEV) can be matched with the car engine performance and fuel economy and emission in the aspects ofsuperior internal-combustion vehicles.Along with the computer and electronic product constantly upgrading electric car, open class in mature technology and perfected, that drive more safe, convenient and flexible, comfortable. Now, the electric car from ordinary consumers distance is still very far away, only a few people in bandwagon. Electric cars with traditional to compete in the market, the carwill was electric cars and intelligent car replaced. This is the question that day after timing will come. ABS, GPS, and various new 4WD 4WS, electronic products and the modern era, excellent performance auto tacit understanding is tie-in, bring us unparalleled precision driving comfort and safety of driving.译文:随着世界能源危机的持续,以及战争和能源-----石油的消耗及汽车饱有量的增加,能源在一天一天下降,终有一天它会消失的无影无踪。
3-电气工程及其自动化专业 外文文献 英文文献 外文翻译 plc方面
1、外文原文(复印件)A: Fundamentals of Single-chip MicrocomputerTh e si ng le-ch i p mi cr oc om pu ter is t he c ul mi nat i on o f bo th t h e d ev el op me nt o f th e d ig it al com p ut er an d t he int e gr at ed ci rc ui ta r gu ab ly th e t ow m os t s i gn if ic ant i nv en ti on s o f t h e 20t h c en tu ry[1].Th es e to w typ e s of a rc hi te ctu r e ar e fo un d i n s in gl e-ch ip m i cr oc om pu te r. So m e em pl oy t he sp l it p ro gr am/d ata me mo ry o f th e H a rv ar d ar ch it ect u re, sh ow n in Fi g.3-5A-1, o th ers fo ll ow t hep h il os op hy, wi del y a da pt ed f or ge n er al-p ur po se co m pu te rs a ndm i cr op ro ce ss or s, of ma ki ng no lo gi c al di st in ct io n be tw ee n p ro gr am a n d da ta m em or y a s i n th e Pr in cet o n ar ch it ec tu re,sh ow n inF i g.3-5A-2.In g en er al te r ms a s in gl e-chi p m ic ro co mp ut er i sc h ar ac te ri zed b y the i nc or po ra tio n of al l t he uni t s o f a co mp ut er i n to a s in gl e dev i ce, as s ho wn in Fi g3-5A-3.Fig.3-5A-1 A Harvard typeFig.3-5A-2. A conventional Princeton computerFig3-5A-3. Principal features of a microcomputerRead only memory (ROM).R OM i s u su al ly f or th e p er ma ne nt,n o n-vo la ti le s tor a ge o f an a pp lic a ti on s pr og ra m .M an ym i cr oc om pu te rs an d mi cr oc on tr ol le r s a re in t en de d fo r h ig h-v ol ume a p pl ic at io ns a nd h en ce t he e co nom i ca l ma nu fa ct ure of t he d ev ic es r e qu ir es t ha t the co nt en ts o f the pr og ra m me mo ry b e co mm it te dp e rm an en tl y d ur in g th e m an uf ac tu re o f c hi ps . Cl ear l y, th is im pl ie sa ri g or ou s a pp roa c h t o R OM co de d e ve lo pm en t s in ce c ha ng es ca nn otb e m ad e af te r man u fa ct ur e .T hi s d e ve lo pm en t pr oce s s ma y in vo lv e e m ul at io n us in g a s op hi st ic at ed deve lo pm en t sy st em w i th a ha rd wa re e m ul at io n ca pa bil i ty a s we ll a s th e u se of po we rf ul so ft wa re t oo ls.So me m an uf act u re rs p ro vi de ad d it io na l RO M opt i on s byi n cl ud in g i n th ei r ra ng e de vi ce s wi th (or i nt en de d fo r us e wi th) u s er pr og ra mm ab le m em or y. Th e s im p le st of th es e i s us ua ll y d ev ice w h ic h ca n op er ate in a m ic ro pr oce s so r mo de b y usi n g so me o f th e i n pu t/ou tp ut li ne s as a n ad dr es s an d da ta b us f or acc e ss in g e x t er na l m e mo ry. T hi s t ype o f d ev ic e c an b e ha ve fu nc ti on al l y a s t he si ng le c h ip mi cr oc om pu te r fr om wh ic h i t i s de ri ve d a lb eit w it h r es tr ic ted I/O an d a mo di fie d e xt er na l ci rcu i t. T he u se o f t h es e RO Ml es sd e vi ce s is c om mo n e ve n in p ro du ct io n c ir cu it s wh er e t h e v ol um e do es n o t ju st if y th e d e ve lo pm en t co sts of c us to m on-ch i p RO M[2];t he re c a n st il l b e a si g ni fi ca nt s a vi ng in I/O a nd ot he r c hi ps co mp ar ed t o a c on ve nt io nal mi cr op ro ce ss or b as ed c ir cu it. M o re e xa ctr e pl ac em en t fo r RO M d ev ic es c an b e o bt ai ne d in t he f o rm o f va ri an ts w i th 'pi gg y-ba ck'EP RO M(Er as ab le p ro gr am ma bl e ROM)s oc ke ts o rd e vi ce s w it h EP ROM i ns te ad o f R OM 。
电气 自动化 外文文献 外文翻译 英文文献
外文出处:Farhadi, A. (2008). Modeling, simulation, and reduction of conducted electromagnetic interference due to a pwm buck type switching power supply. Harmonics and Quality of Power, 2008. ICHQP 2008. 13th International Conference on, 1 - 6.Modeling, Simulation, and Reduction of Conducted Electromagnetic Interference Due to a PWM Buck Type Switching Power Supply IA. FarhadiAbstract:Undesired generation of radiated or conducted energy in electrical systems is called Electromagnetic Interference (EMI). High speed switching frequency in power electronics converters especially in switching power supplies improves efficiency but leads to EMI. Different kind of conducted interference, EMI regulations and conducted EMI measurement are introduced in this paper. Compliancy with national or international regulation is called Electromagnetic Compatibility (EMC). Power electronic systems producers must regard EMC. Modeling and simulation is the first step of EMC evaluation. EMI simulation results due to a PWM Buck type switching power supply are presented in this paper. To improve EMC, some techniques are introduced and their effectiveness proved by simulation.Index Terms:Conducted, EMC, EMI, LISN, Switching SupplyI. INTRODUCTIONFAST semiconductors make it possible to have high speed and high frequency switching in power electronics []1. High speed switching causes weight and volume reduction of equipment, but some unwanted effects such as radio frequency interference appeared []2. Compliance with electromagnetic compatibility (EMC) regulations is necessary for producers to present their products to the markets. It is important to take EMC aspects already in design phase []3. Modeling and simulation is the most effective tool to analyze EMC consideration before developing the products. A lot of the previous studies concerned the low frequency analysis of power electronics components []4[]5. Different types of power electronics converters are capable to be considered as source of EMI. They could propagate the EMI in both radiated and conducted forms. Line Impedance Stabilization Network (LISN) is required for measurement and calculation of conducted interference level []6. Interference spectrum at the output of LISN is introduced as the EMC evaluation criterion []7[]8. National or international regulations are the references forthe evaluation of equipment in point of view of EMC []7[]8.II. SOURCE, PATH AND VICTIM OF EMIUndesired voltage or current is called interference and their cause is called interference source. In this paper a high-speed switching power supply is the source of interference.Interference propagated by radiation in area around of an interference source or by conduction through common cabling or wiring connections. In this study conducted emission is considered only. Equipment such as computers, receivers, amplifiers, industrial controllers, etc that are exposed to interference corruption are called victims. The common connections of elements, source lines and cabling provide paths for conducted noise or interference. Electromagnetic conducted interference has two components as differential mode and common mode []9.A. Differential mode conducted interferenceThis mode is related to the noise that is imposed between different lines of a test circuit by a noise source. Related current path is shown in Fig. 1 []9. The interference source, path impedances, differential mode current and load impedance are also shown in Fig. 1.B. Common mode conducted interferenceCommon mode noise or interference could appear and impose between the lines, cables or connections and common ground. Any leakage current between load and common ground couldbe modeled by interference voltage source.Fig. 2 demonstrates the common mode interference source, common mode currents Iandcm1 and the related current paths[]9.The power electronics converters perform as noise source Icm2between lines of the supply network. In this study differential mode of conducted interference is particularly important and discussion will be continued considering this mode only.III. ELECTROMAGNETIC COMPATIBILITY REGULATIONS Application of electrical equipment especially static power electronic converters in different equipment is increasing more and more. As mentioned before, power electronics converters are considered as an important source of electromagnetic interference and have corrupting effects on the electric networks []2. High level of pollution resulting from various disturbances reduces the quality of power in electric networks. On the other side some residential, commercial and especially medical consumers are so sensitive to power system disturbances including voltage and frequency variations. The best solution to reduce corruption and improve power quality is complying national or international EMC regulations. CISPR, IEC, FCC and VDE are among the most famous organizations from Europe, USA and Germany who are responsible for determining and publishing the most important EMC regulations. IEC and VDE requirement and limitations on conducted emission are shown in Fig. 3 and Fig. 4 []7[]9.For different groups of consumers different classes of regulations could be complied. Class Afor common consumers and class B with more hard limitations for special consumers are separated in Fig. 3 and Fig. 4. Frequency range of limitation is different for IEC and VDE that are 150 kHz up to 30 MHz and 10 kHz up to 30 MHz respectively. Compliance of regulations is evaluated by comparison of measured or calculated conducted interference level in the mentioned frequency range with the stated requirements in regulations. In united European community compliance of regulation is mandatory and products must have certified label to show covering of requirements []8.IV. ELECTROMAGNETIC CONDUCTED INTERFERENCE MEASUREMENTA. Line Impedance Stabilization Network (LISN)1-Providing a low impedance path to transfer power from source to power electronics converter and load.2-Providing a low impedance path from interference source, here power electronics converter, to measurement port.Variation of LISN impedance versus frequency with the mentioned topology is presented inFig. 7. LISN has stabilized impedance in the range of conducted EMI measurement []7.Variation of level of signal at the output of LISN versus frequency is the spectrum of interference. The electromagnetic compatibility of a system can be evaluated by comparison of its interference spectrum with the standard limitations. The level of signal at the output of LISN in frequency range 10 kHz up to 30 MHz or 150 kHz up to 30 MHz is criterion of compatibility and should be under the standard limitations. In practical situations, the LISN output is connected to a spectrum analyzer and interference measurement is carried out. But for modeling and simulation purposes, the LISN output spectrum is calculated using appropriate software.基于压降型PWM开关电源的建模、仿真和减少传导性电磁干扰摘要:电子设备之中杂乱的辐射或者能量叫做电磁干扰(EMI)。
电力电子英文文献1
i THE INTEGRATION of I building and business systems ; within so-called 'intelligent i buildings' will create a range : of new potential risks - such I ascyber-attacks-forthe I personnel, technology, and i operations within them, ; warns an IET report, i The authors of the Sector I Insight report 'Intelligent i Buildings: Understanding and i managing the security risks' : warn that third parties gaining : unauthorised access to IP-based I building management systems i could disable or take control of i building systems, with the result I that continued occupation might : no longer be safe, due to physical i damage (fire orflooding,say) or i other life-threatening actions. ; People in intelligent buildings I might bypass security controls : or operate systems incorrectly by i accident or design, the report i suggests. Integration of j previously disparate systems can i magnify the Impact of errors or : omissions, and while intelligent I buildings' systems integration i brings together IT and facilities : management teams, they may : have different priorities, i cultures, and reporting chains i - all of which could "inhibit an i effective response to incidents or I faults". : "Intelligent buildings are \ potentially mission-critical i environments," says IET ; cyber-security lead Hugh Boyes, ; one of the report's authors.
电力专业英语 英文文献翻译报告
Page 1.The Production of Electrical Energy(电能生产)1 English textFrom reference 1Should the generation be not adequate to balance the load demand, it is imperative that one of following alternatives be considered for keeping the system in operating condition:1. Staring fast peaking units,2. Load shedding for unimportant loads,3. generation rescheduling.It is apparent from the above that since the voltage specifications are not stringent, load frequency control is by far the most important in power system control.In order to understand the frequency control, consider a small step-increase in load. The initial distribution of the load increment is determined by the system simpedance; and the sistantaneous relative generator rotor positions. The energy required to supply the load increment is drawn from the kinetic energy of rotating machines. As a result, the system frequency drops. The distribution of load during this period among the various machines is determined by the inertias of the rotors of the generators partaking in process. This problem is stability analysis of the system.After the speed or frequency fall due to reduction in stored energy in the rotors has taken place, the drop is sensed by the governors and they divide the load increment between the machines as determined by the droops of the respective governor characterstics. Subsequently, secondary control restores the system frequency to its normal value by readjusting the governor characteristics. Keywords:load frequency controlFrom reference 2Modern power systems are so large that it is impossible to design a single central control system that would handle the overall control job. It is extremely useful take into account the weak links in the system and then apply control throughdecomposition. The demarcation of load frequency control and Mavar voltage control characteristics is one such decomposition. Geographical and functional decomposition are successfully applied to power systems and this leads to the concept of area control.A modern power system can be divided into several areas for load frequency control. Each control area fulfils the following:1.The area is a geographically contious portion of a large interconnected area, which adjusts its own generation to accommodate load changes within its precincts.2.Under normal conditions of operation, it changes bulk power with neighboring areas.3.Under abnormal conditions of operation, it may deviate from predetermined schedules and provide assistance to any neighboring control area in the system.4.It is expected, in addition, to partake with the other areas in the system in a suitable manner in the system frequency regulation.The rotors of all generators in a control area swing together for load change. Thus, a coherent group of generators within a geographical region may constitute a control area which is connected to other similar areas by weak tie lines.Keywords:areas load frequency controlFrom reference 3For plant loading schedules in thermal systems, load prediction up to two hours in advance is necessary while for unit commitment schedules prediction up to 24 hours is sufficient. Also, at all sations and control centers, short-time prediction is needed for storage and display of advance information. Based on this information, predictive security assessment of the system is made. This also helps to contain the rates of change of generator outputs within their permissible limits.For the implementation of economic scheduling of generation using digital computers, detailed estimates of the future load demands are essential in order to allow sufficient time for the calculation and implementation of the generator schedules. Whatever method is envisaged for the calculation of such economic schedules consistent with the security and spare requirements of the system, the schedules should be calculatedevery 15 or 30 minutes and each economic schedule should be a predictive one ,for at least about 30 minutes ahead of event. It is then obvious that the predictions are to be revised frequently in the light of any fresh information so as to minimize the estimation errors.Peak load demand forecasts are useful in determining the investment required for additional generating and transmission capacities required. Forecasts for planning require data extending over several previous years. Meaningful forecasts can be obtained with lead time of 3 to 5 years.Keywords:load predictionFrom reference 4In this method, the load is separated into two main components. The first component is a base load which is of fixed value and the second a variable component which is a function of the weather conditions.Estimates can be made 24 hours ahead, using the weather forecast. The temperature base for weighting the effect of the predicated temperature on the load is the normal, mean temperature of the month. The normal, mean temperature of the month has zero weight. Similarly the change in consumers demand due to cloudy weather may be assumed to vary in direct proportion to the degree of cloudiness. This in turn may be expressed by an illumination index with fair, clear sky corresponding to zero weight.The base load is determined from past records. Proper weighting of the elements of the weather will be attained only after several trials. The method of prediction stabilizes after this trial period. It may be noted that the base loads for week days and weekend will generally be different for any hour.Using these base loads, a load estimate based on the best available weather forecast can be made using proper weighting of meteorological factors like temperature, cloudiness, wind velocity, etc.Keywords:proper weighting of the elements of the weather2 中文翻译及分析出自文献1:万一发电量不足以平衡负荷需求,要使电力系统处于运行状态,必须考虑采取以下选择方法中的一种:1、启动快速峰荷机组2、对不重要的用户实行拉闸断电3、重新制定发电计划从上述情况来看,电压技术的要求并不严格,目前为止负荷频率控制是电力系统控制中最重要的手段。
电力电子英文作文
电力电子英文作文英文:Electric power electronics is a crucial field in the modern world, as it plays a vital role in the conversion, control, and conditioning of electric power. This technology is used in a wide range of applications, from renewable energy systems and electric vehicles to industrial motor drives and consumer electronics.One of the most common examples of electric power electronics in everyday life is the power supply for electronic devices. For instance, the charger for a smartphone uses power electronics to convert the AC power from the wall outlet into DC power that can be used to charge the phone. Without power electronics, it would be impossible to charge our devices efficiently and safely.Another example is the use of power electronics in renewable energy systems. Solar panels and wind turbinesgenerate DC power, which needs to be converted to AC power for use in our homes and businesses. This conversion is made possible by power electronics, allowing us to harness renewable energy sources and reduce our reliance on fossil fuels.In addition to these examples, power electronics also play a crucial role in electric vehicles. The motor drive system in an electric car relies on power electronics to control the speed and torque of the motor, as well as to manage the energy flow between the battery and the motor. This technology is essential for the widespread adoption of electric vehicles and the reduction of greenhouse gas emissions from transportation.Overall, electric power electronics have revolutionized the way we generate, distribute, and consume electric power. Without this technology, many of the conveniences and advancements of the modern world would not be possible.中文:电力电子在现代世界中扮演着至关重要的角色,它在电力转换、控制和调节中起着至关重要的作用。
外文翻译—电力电子技术(英文+译文)
1 Power Electronic ConceptsPower electronics is a rapidly developing technology. Components are tting higher current and voltage ratings, the power losses decrease and the devices become more reliable. The devices are also very easy tocontrol with a mega scale power amplification. The prices are still going down pr. kVA and power converters are becoming attractive as a mean to improve the performance of a wind turbine. This chapter will discuss the standard power converter topologies from the simplest converters for starting up the turbine to advanced power converter topologies, where the whole power is flowing through the converter. Further, different park solutions using power electronics arealso discussed.1.1 Criteria for concept evaluationThe most common topologies are selected and discussed in respect to advantages and drawbacks. Very advanced power converters, where many extra devices are necessary in order to get a proper operation, are omitted.1.2 Power convertersMany different power converters can be used in wind turbine applications. In the case of using an induction generator, the power converter has to convert from a fixed voltage and frequency to a variable voltage and frequency. This may be implemented in many different ways, as it will be seen in the next section. Other generator types can demand other complex protection. However, the most used topology so far is a soft-starter, which is used during start up in order to limit the in-rush current and thereby reduce the disturbances to the grid.1.2.1 Soft starterThe soft starter is a power converter, which has been introduced to fixedspeed wind turbines to reduce the transient current during connection or disconnection of the generator to the grid. When the generator speed exceeds the synchronous speed, the soft-starter is connected. Using firing angle control of the thyristors in the soft starter the generator is smoothly connected to the grid over a predefined number of grid periods. An example of connection diagram for the softstarter with a generator is presented in Figure1.Figure 1. Connection diagram of soft starter with generators.The commutating devices are two thyristors for each phase. These are connected in anti-parallel. The relationship between the firing angle (﹤) and the resulting amplification of the soft starter is non-linear and depends additionally on the power factor of the connected element. In the case of a resistive load, may vary between 0 (full on) and 90 (full off) degrees, in the case of a purely inductive load between 90 (full on) and 180 (full off) degrees. For any power factor between 0 and 90 degrees, w ill be somewhere between the limits sketched in Figure 2.Figure 2. Control characteristic for a fully controlled soft starter.When the generator is completely connected to the grid a contactor (Kbyp) bypass the soft-starter in order to reduce the losses during normal operation. The soft-starter is very cheap and it is a standard converter in many wind turbines.1.2.2 Capacitor bankFor the power factor compensation of the reactive power in the generator, AC capacitor banks are used, as shown in Figure 3. The generators are normally compensated into whole power range. The switching of capacitors is done as a function of the average value of measured reactive power during a certain period.Figure 3. Capacitor bank configuration for power factor compensation ina wind turbine.The capacitor banks are usually mounted in the bottom of the tower or in thenacelle. In order to reduce the current at connection/disconnection of capacitors a coil (L) can be connected in series. The capacitors may be heavy loaded and damaged in the case of over-voltages to the grid and thereby they may increase the maintenance cost.1.2.3 Diode rectifierThe diode rectifier is the most common used topology in power electronic applications. For a three-phase system it consists of six diodes. It is shown in Figure 4.Figure 4. Diode rectifier for three-phase ac/dc conversionThe diode rectifier can only be used in one quadrant, it is simple and it is notpossible to control it. It could be used in some applications with a dc-bus.1.2.4 The back-to-back PWM-VSIThe back-to-back PWM-VSI is a bi-directional power converter consisting of two conventional PWM-VSI. The topology is shown in Figure 5.To achieve full control of the grid current, the DC-link voltage must be boosted to a level higher than the amplitude of the grid line-line voltage. The power flow of the grid side converter is controlled in orderto keep the DC-link voltage constant, while the control of the generator side is set to suit the magnetization demand and the reference speed. The control of the back-to-back PWM-VSI in the wind turbine application is described in several papers (Bogalecka, 1993), (Knowles-Spittle et al., 1998), (Pena et al., 1996), (Yifan & Longya, 1992), (Yifan & Longya, 1995).Figure 5. The back-to-back PWM-VSI converter topology.1.2.4.1 Advantages related to the use of the back-to-back PWM-VSIThe PWM-VSI is the most frequently used three-phase frequency converter. As a consequence of this, the knowledge available in the field is extensive and well established. The literature and the available documentation exceed that for any of the other converters considered in this survey. Furthermore, many manufacturers produce components especially designed for use in this type of converter (e.g., a transistor-pack comprising six bridge coupled transistors and anti paralleled diodes). Due to this, the component costs can be low compared to converters requiring components designed for a niche production.A technical advantage of the PWM-VSI is the capacitor decoupling between the grid inverter and the generator inverter. Besides affording some protection, this decoupling offers separate control of the two inverters, allowing compensation of asymmetry both on the generator side and on the grid side, independently.The inclusion of a boost inductance in the DC-link circuit increases the component count, but a positive effect is that the boost inductance reduces the demands on the performance of the grid side harmonic filter, and offers some protection of the converter against abnormal conditions on the grid.1.2.4.2 Disadvantages of applying the back-to-back PWM-VSIThis section highlights some of the reported disadvantages of the back-to-back PWM-VSI which justify the search for a more suitable alternative converter:In several papers concerning adjustable speed drives, the presence of the DC link capacitor is mentioned as a drawback, since it is heavy and bulky, it increases the costs and maybe of most importance, - it reduces the overall lifetime of the system. (Wen-Song & Ying-Yu, 1998); (Kim & Sul, 1993); (Siyoung Kim et al., 1998).Another important drawback of the back-to-back PWM-VSI is the switching losses. Every commutation in both the grid inverter and the generator inverter between the upper and lower DC-link branch is associated with a hard switching and a natural commutation. Since the back-to-back PWM-VSI consists of two inverters, the switching losses might be even more pronounced. The high switching speed to the grid may also require extra EMI-filters.To prevent high stresses on the generator insulation and to avoid bearing current problems (Salo & Tuusa, 1999), the voltage gradient may have to be limited by applying an output filter.1.2.5 Tandem converterThe tandem converter is quite a new topology and a few papers only have treated it up till now ((Marques & Verdelho, 1998); (Trzynadlowski et al., 1998a); (Trzynadlowski et al., 1998b)). However, the idea behind the converter is similar to those presented in ((Zhang et al., 1998b)), where the PWM-VSI is used as an active harmonic filter to compensate harmonic distortion. The topology of the tandem converter is shown inFigure 6.Figure 6. The tandem converter topology used in an induction generator wind turbine system.The tandem converter consists of a current source converter, CSC, in thefollowing designated the primary converter, and a back-to-back PWM-VSI, designated the secondary converter. Since the tandem converter consists of four controllable inverters, several degrees of freedom exist which enable sinusoidal input and sinusoidal output currents. However, in this context it is believed that the most advantageous control of the inverters is to control the primary converter to operate in square-wave current mode. Here, the switches in the CSC are turned on and off only once per fundamental period of the input- and output current respectively. In square wave current mode, the switches in the primary converter may either be GTO.s, or a series connection of an IGBT and a diode.Unlike the primary converter, the secondary converter has to operateat a high switching frequency, but the switched current is only a small fraction of the total load current. Figure 7 illustrates the current waveform for the primary converter, the secondary converter, is, and the total load current il.In order to achieve full control of the current to/from the back-to-back PWMVSI, the DC-link voltage is boosted to a level above the grid voltage. As mentioned, the control of the tandem converter is treated in only a few papers. However, the independent control of the CSC and the back-to-back PWM-VSI are both well established, (Mutschler & Meinhardt, 1998); (Nikolic & Jeftenic, 1998); (Salo & Tuusa, 1997); (Salo & Tuusa, 1999).Figure 7. Current waveform for the primary converter, ip, the secondary converter, is, and the total load current il.1.2.5.1Advantages in the use of the Tandem ConverterThe investigation of new converter topologies is commonly justifiedby thesearch for higher converter efficiency. Advantages of the tandem converter are the low switching frequency of the primary converter, and the low level of the switched current in the secondary converter. It is stated that the switching losses of a tandem inverter may be reduced by 70%, (Trzynadlowski et al., 1998a) in comparison with those of an equivalent VSI, and even though the conduction losses are higher for the tandem converter, the overall converter efficiency may be increased.Compared to the CSI, the voltage across the terminals of the tandem converter contains no voltage spikes since the DC-link capacitor of the secondary converter is always connected between each pair of input- and output lines (Trzynadlowski et al., 1998b).Concerning the dynamic properties, (Trzynadlowski et al., 1998a) states that the overall performance of the tandem converter is superior to both the CSC and the VSI. This is because current magnitude commands are handled by the voltage source converter, while phase-shift current commands are handled by the current source converter (Zhang et al., 1998b).Besides the main function, which is to compensate the current distortion introduced by the primary converter, the secondary converter may also act like an active resistor, providing damping of the primary inverter in light load conditions (Zhang et al., 1998b).1.2.5.2 Disadvantages of using the Tandem ConverterAn inherent obstacle to applying the tandem converter is the high number of components and sensors required. This increases the costs and complexity of both hardware and software. The complexity is justified by the redundancy of the system (Trzynadlowski et al., 1998a), however the system is only truly redundant if a reduction in power capability and performance is acceptable.Since the voltage across the generator terminals is set by the secondary inverter, the voltage stresses at the converter are high.Therefore the demands on the output filter are comparable to those when applying the back-to-back PWM-VSI.In the system shown in Figure 38, a problem for the tandem converter in comparison with the back-to-back PWM-VSI is the reduced generator voltage. By applying the CSI as the primary converter, only 0.866% of the grid voltage can be utilized. This means that the generator currents (and also the current through the switches) for the tandem converter must be higher in order to achieve the same power.1.2.6 Matrix converterIdeally, the matrix converter should be an all silicon solution with no passive components in the power circuit. The ideal conventional matrix converter topology is shown in Figure 8.Figure 8. The conventional matrix converter topology.The basic idea of the matrix converter is that a desired input current (to/from the supply), a desired output voltage and a desired output frequency may be obtained by properly connecting the output terminals of the converter to the input terminals of the converter. In order to protect the converter, the following two control rules must be complied with: Two (or three) switches in an output leg are never allowed to be on at the same time. All of the three output phases must be connected to an input phase at any instant of time. The actual combination of the switchesdepends on the modulation strategy.1.2.6.1 Advantages of using the Matrix ConverterThis section summarises some of the advantages of using the matrix converter in the control of an induction wind turbine generator. For a low output frequency of the converter the thermal stresses of the semiconductors in a conventional inverter are higher than those in a matrix converter. This arises from the fact that the semiconductors in a matrix converter are equally stressed, at least during every period of the grid voltage, while the period for the conventional inverter equals the output frequency. This reduces thethermal design problems for the matrix converter.Although the matrix converter includes six additional power switches compared to the back-to-back PWM-VSI, the absence of the DC-link capacitor may increase the efficiency and the lifetime for the converter (Schuster, 1998). Depending on the realization of the bi-directional switches, the switching losses of the matrix inverter may be less than those of the PWM-VSI, because the half of the switchings become natural commutations (soft switchings) (Wheeler & Grant, 1993).1.2.6.2 Disadvantages and problems of the matrix converterA disadvantage of the matrix converter is the intrinsic limitation of the output voltage. Without entering the over-modulation range, the maximum output voltage of the matrix converter is 0.866 times the input voltage. To achieve the same output power as the back-to-back PWM-VSI, the output current of the matrix converter has to be 1.15 times higher, giving rise to higher conducting losses in the converter (Wheeler & Grant, 1993).In many of the papers concerning the matrix converter, the unavailability of a true bi-directional switch is mentioned as one of the major obstacles for the propagation of the matrix converter. In the literature, three proposals for realizing a bi-directional switch exists. The diode embedded switch (Neft & Schauder, 1988) which acts like a truebi-directional switch, the common emitter switch and the common collector switch (Beasant et al., 1989).Since real switches do not have infinitesimal switching times (which is not desirable either) the commutation between two input phases constitutes a contradiction between the two basic control rules of the matrix converter. In the literature at least six different commutation strategies are reported, (Beasant et al., 1990); (Burany, 1989); (Jung & Gyu, 1991); (Hey et al., 1995); (Kwon et al., 1998); (Neft & Schauder, 1988). The most simple of the commutation strategies are those reported in (Beasant et al., 1990) and (Neft & Schauder, 1988), but neither of these strategies complies with the basic control rules.译文1 电力电子技术的内容电力电子技术是一门正在快速发展的技术,电力电子元器件有很高的额定电流和额定电压,它的功率减小元件变得更加可靠、耐用.这种元件还可以用来控制比它功率大很多倍的元件。
电力电子英文文献3
20 Engineered Systems December 2012BY PAUL EHRLICH, P .E.᭤Over the years, I have written articles, delivered talks,and participated in industry events promoting the concept of the “intelligent building.” So, when I was recently asked by a colleague to define the concept of an intel-ligent building, I was ready to roll out a standard answer, such as,“Use of technology and process to create a sustainable building that is more productive for its occupants, and more operationally efficient for its owners.”This would be followed by a description of open systems, net-works, and integration of building systems. Instead, I paused and realized that while all of that is true, there is a large gap between the theoretical definition of an intelligent building and the prac-tical project delivery that we work on every day. The theoretical smart building has building systems on a shared enterprise net-work and a vast variety of systems connected including HVAC and lighting, fire alarm, security, elevators, blinds, etc. The prac-tical systems are driven by owners’ goals to reduce energy costs and to provide a practical platform for operations. Here are the key characteristics of what comprise these systems:• O pen systems: This is a given with the use of open protocols such as BACnet ®, LonMark ®, and Modbus. User interface is typically web based whenever possible.• C onnected systems: What gets connected typically is focused on those systems that utilize energy. HVAC is always connected. When economically practical, lighting may also be included. Thevalue proposition to connect any other systems gets carefullyscrutinized. In some cases, it may make good sense to connect the fire alarm system for secondary annunciation or to connect to elevators. But in most cases, these systems don’t get connected and integrating security and video is almost never included. • N etworks: We see some owners who are actively embracing the use of the enterprise network for building systems, and there are others who see too many challenges with coordination, security, and control to make this worthwhile. Projects end up fairly evenly split between dedicated facility networks and the use of shared enterprise networks.• A pplications: Most projects end up with a series of optimiza-tion strategies of HVAC and lighting systems, resulting in dra-matic efficiency improvements. Other potential applications, such as connection to Smart Grid, analytics, continuous com-missioning, etc., are being designed to be enabled but are notyet broadly deployed.The end result is a practical application that meets owners’goals and provides tangible benefits. With the advent of newenergy efficiency standards under ASHRAE 90.1-2010, the useof optimization and integration is moving from being desirableto required.Without a doubt, intelligent buildings will continue to evolve.What we are delivering today will become an expectation in the future. It is a fairly safe bet that as the benefits to a larger-scale integration are more clearly defined, they are a natural extension to these systems, and the theoretical vision of today may become the practical reality of tomorrow. ES INTELLIGENT BUILDINGS:From Theoretical to PracticalHV AC i s al ways y conne cted . Wh enec on om ic al ly p ra ct ic al ,li gh ti ng ma y al so b e in cl ud ed . Th e va lu e pr op os it io n to c on ne ct a ny o th er sy t st ems ge t s car f ef l ul l y scr t ut i n i z d ed . In some cases, it may ma ke goo dsense to conne ct the fir e al arm sy st em f or s ec on da ry a nn un ci at io n or t o co nn ec t to e le va to rs .Bu t inmo st c as es , th es e sy st em s do n’t ge t connec t e d , a d nd i t nt egra ti ng secu rity a nd v id eo i s al mo st neverincluded .Reality ushers in more factors than simply what the technology can do.᭤BuildingAutomation Ehrlich has worked on a series of ASHRAE projects including the BACnet committee and “Guideline 13 – Specify-ing DDC Controls.” The formation of theBuilding Intelligence Group allowed him to provide assistance to owners with the plan-ning, design, and development of Intelligent Building Systems. Email him at paul@.Building Intelligence Group provides ser-vices for clients worldwide including leading Universities, Corporations, and Developers. More information can be found at .Copyright of Engineered Systems is the property of BNP Media and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.。
毕业设计英文文献翻译(电力方向附带中文)
毕业设计英文文献翻译(电力方向附带中文)大学毕业设计英文文献翻译 ,关于电力系统方向,电力谐波!绝对原创!HarmonicsService reliability and quality of power have become growing concerns for many facility managers, especially with the increasing sensitivity of electronic equipment and automated controls. There are several types of voltage fluctuations that can cause problems, including surges and spikes, sags, harmonic distortion, and momentary disruptions. Harmonics can cause sensitive equipment to malfunction and other problems, including overheating of transformers and wiring, nuisance breaker trips, and reduced power factor.What Are Harmonics?Harmonics are voltage and current frequencies riding on top of the normal sinusoidal voltage and current waveforms. Usually these harmonic frequencies are in multiples of the fundamental frequency, which is 60 hertz (Hz) in the US and Canada. The most common source of harmonic distortion is electronic equipment using switch-mode power supplies, such as computers, adjustable-speed drives, and high-efficiency electronic light ballasts.Harmonics are created by these ―switching loads‖ (also called “nonlinear loads,‖ because current does not vary smoothly with voltage as it does with simple resistive and reactive loads): Each time the current is switched on and off, a current pulse is created. The resulting pulsed waveform is made up of a spectrum of harmonic frequencies, including the 60 Hz fundamental and multiples of it. This voltage distortion typically results from distortion in the current reacting with system impedance. (Impedance is a measure of the total opposition—resistance, capacitance, and inductance—to the flow of an alternating current.) Thehigher-frequency waveforms, collectively referred to as total harmonic distortion (THD), perform no useful work and can be asignificant nuisance.Harmonic waveforms are characterized by their amplitude and harmonic number. In the U.S. and Canada, the third harmonic is 180 Hz—or 3 x 60 Hz—and the fifth harmonic is 300 Hz (5 x 60 Hz). The third harmonic (and multiples of it) is the largest problem in circuits with single-phase loads such as computers and fax machines. Figure 1 shows how the 60-Hz alternating current (AC) voltage waveform changes when harmonics are added.。
电力电子技术外文翻译文献
电力电子技术外文翻译文献(文档含中英文对照即英文原文和中文翻译)译文:基于单片机的开关电源1 用途开关电源产品在工业自动化控制、军工设备、科研设备、LED照明、工控设备、通讯设备、电力设备、仪器仪表、医疗设备、半导体制冷制热、空气净化器,电子冰箱,液晶显示器,LED灯具,通讯设备,视听产品,安防,电脑机箱,数码产品和仪器类等领域中得到广泛应用。
2 简介随着电力电子技术的高速发展,电力电子设备与人们的工作、生活的关系日益密切,而电子设备都离不开可靠的电源,进入80年代计算机电源全面实现了开关电源化,率先完成计算机的电源换代,进入90年代开关电源相继进入各种电子、电器设备领域,程控交换机、通讯、电子检测设备电源、控制设备电源等都已广泛地使用了开关电源,更促进了开关电源技术的迅速发展。
开关电源是利用现代电力电子技术,控制开关晶体管开通和关断的时间比率,维持稳定输出电压的一种电源,开关电源一般由脉冲宽度调制(PWM)控制IC和开关器件(MOSFET、BJT等)构成。
开关电源和线性电源相比,二者的成本都随着输出功率的增加而增长,但二者增长速率各异。
线性电源成本在某一输出功率点上,反而高于开关电源。
随着电力电子技术的发展和创新,使得开关电源技术在不断地创新,这一成本反转点日益向低输出电力端移动,这为开关电源提供了广泛的发展空间。
开关电源高频化是其发展的方向,高频化使开关电源小型化,并使开关电源进入更广泛的应用领域,特别是在高新技术领域的应用,推动了高新技术产品的小型化、轻便化。
另外开关电源的发展与应用在节约能源、节约资源及保护环境方面都具有重要的意义。
3 分类现代开关电源有两种:一种是直流开关电源;另一种是交流开关电源。
这里主要介绍的只是直流开关电源,其功能是将电能质量较差的原生态电源(粗电),如市电电源或蓄电池电源,转换成满足设备要求的质量较高的直流电压(精电)。
直流开关电源的核心是DC/DC转换器。
因此直流开关电源的分类是依赖DC/DC转换器分类的。
电力电子外文摘要综述翻译
综述1、Modeling, Control, and Implementation of DC–DC Converters for Variable Frequency Operation频率可变的DC-DC变换器的建模,和实现Abstract—In this paper, novel small-signal averaged models for dc–dc converters operating at variable switching frequency are derived. This is achieved by separately considering the on-time and the off-time of the switching period. The derivation is shown in detail for a synchronous buck converter and the model for a boost converter is also presented. The model for the buck converter is then used for the design of two digital feedback controllers, which exploit the additional insight in the converter dynamics. First, a digital multiloop PID controller is implemented, where the design is based on loop-shaping of the proposed frequency-domain transfer functions. And second, the design and the implementation of a digital LQG state-feedback controller, based on the proposed time-domain state-space model, is presented for the same converter topology. Experimental results are given for the digital multiloop PID controller integrated on an application-specified integrated circuit in a 0.13μmCMOS technology, as well as for the statefeedback controller implemented on an FPGA. Tight output voltage regulation and an excellent dynamic performance is achieved, as the dynamics of the converter under variable frequency operation are considered during the design of both implementations.本文中利用小信号的平均值通过变频开关实现DC-DC的变换,通过单独控制导通和关断时间,并建立了back拓扑模型和boost拓扑模型,该模型的buck转换器用于两个数字反馈控制器,实现变换器的动态控制。
电力电子外文文献翻译
模拟神经网络的动态学习模拟电子电路摘要:在神经网络领域,许多应用模型已经提出了。
一个神经芯片和一个人工视网膜芯片的开发,以包括生物医学视觉系统的神经网络模型及其仿真。
以前的模拟神经网络模型的运算放大器和固定电阻。
改变连接系数是很困难的。
在这项研究中,我们用模拟电子多路电路。
连接权重描述输入电压。
改变连接系数很容易。
该模型的工作原理只有模拟电路。
它可以完成学习过程中的一个非常时间短,这种模式将使更灵活的学习。
关键词:电子电路,神经网络,模拟电子1.简介:我们提出透过利用模拟神经电路进行神经网络的动态学习。
这种模式会发展出一个包括模拟神经电路的全新的信号装置。
其中一个研究目标是生物医学神经功能的建模。
在神经网络领域中,许多应用模型已被提出,而且有许多硬件模型已经实现了。
这些模拟神经网络模型,是由operational amplifier及fixed resistance所组成的‧这是个非常困难去改变这个连接系数的(指operational amplifier及fixed resistance)1.1模拟神经网络模拟神经网络是通过电压,电流或电荷的连续数量来表达的。
而其最主要的优点是它不但可以透过时钟操作去建造连续时间系统,还可以建造离散时间系统。
明显地actual neuron cell是模拟工作。
使用模拟方法去模仿神经元细胞的运作是可行的。
许多人工神经网络LSI就是用analog method来设计的。
很多processing units可以安装在single-chip上,因为每一个单元都可以由小数量的元件,加法,乘法,以及非线性变换来实现。
还有使用super parallelcalculation来操作是可行的。
结论是,与神经网络算法相比高速工作是有其的好处的。
在纯模拟电路中,最大的问题是奴何去实现模拟内存及如何记住模拟量。
到目前为止也还没找到相应的解决方法。
DRAM method是一些记录存在电容器的临时存储,因为它可以与CMOS processs通用。
英文文献 科技类 原文及翻译 (电子 电气 自动化 通信…) 8
Switching Power Supply目录1 Switching Power Supply (1)Linear versus Switching Power Supplies (1)Basic Converters (2)1.2.1Forward-Mode Converter Fundamentals (2)1.2.3 Flyback or Boost-mode Converter Fundamentals (4)1.3 Topologies (5)1 开关电源 (7)1.1 线性电源和开关电源之比拟 (7)根本转换器 (8)1.2.1 前向模式转换器根底 (8)12.2 增压模式转换器根底 (8)1.3 拓扑结构 (9)2 Operational Amplifiers (10)2 放大器 (14)1 Switching Power SupplyEvery new electronic product , except those that battery powered, requires converting off-line 115V ac or 230V ac power to some dc voltage for powering the electronics. Efficient conversion of electrical power is becoming a primary concern to companies and to society as a whole.Switching power supplies offer not only higher efficiencies but also offer greater flexibility to the designer. Recent advances in semiconductor, magnetic and passive technologies make the switching power supply an ever more popular choice in the power conversion arena today.1.1 Linear versus Switching Power SuppliesHistorically, the linear regulator was the primary method of creating a regulated output voltage. It operates by reducing a higher input voltage down to the lower output voltage by linearly controlling the conductivity of a series pass power device in response to changes in its load. This results in a large voltage being placed across the pass unit with the load current flowing through it.This headroom loss ()V I⨯ causes the linear regulator to only be 30 todrop load50 percent efficient. That means that for each watt delivered to the load , at least a watt has to be dissipated in heat. The cost of the heatsink actually makes the linear regulator uneconomical above 10watts for small applications. Below that point, however, they are cost effective in step-down applications.The switching regulator operates the power devices in the full-on and cutoff states. This then results in either large currents being passed through the power devices with a low“on〞voltage or no current flowing with high voltage across the device. This results in a much lower power being dissipated within the supply.The average switching power-supply exhibits efficiencies of between 70 to 90 percent, regardless of the input voltage.Higher levers of integration have driven the cost of switching power supplies downward which makes in an attractive choice for output powers greater than 10 watts or where multiple outputs are desired.1.2 Basic ConvertersForward-Mode Converter FundamentalsThe most elementary forward-mode converter is the Buck or Step-down Converter which can be seen in Figure 3.1.Its operation can be seen as having two distinct time periods which occur when the series power switch is on and off. When the power switch is on ,the inputvoltage is connected to the input of the inductor .The output of switch of inductor is the output voltage, and the rectifier is back-biased. During this period, since there is a constant voltage source connected across the inductor, the inductor current begins to linearly ramp upward which is described by:()()in out on L on V V t i L -⨯=During the “on 〞 period , energy is being stored within the core material of the inductor in the form of flux. There is sufficient energy stored to carry the requirements of the load during the next off period.The next period is the “off 〞 period of the power switch .When the power switch turns off, the input voltage of the inductor flies below ground and is clamped at one diode drop below ground by the catch diode. Current now begins to flow through the catch diode thus maintaining the load current loop. This remove the stored energy from the inductor, The inductor. The inductor current during this time is:()()out D offL off V V t i L -⨯=This period ends when the power switch is once again turned on.Regulation is accomplished by varying the on-to-off duty cycle of the power switch. The relationship which approximately describes its operation is:out in V V ≈∂⨯Where ∂ is the duty cycle (()/on on off t t t ∂=+).The buck converter is capable of kilowatts of output power, but suffers from one serious shortcoming which would occur if the power switch were to fail short-circuited, the input power source is connected directly to the load circuitry with usually produces catastrophic results. To avoid this situation, a crowbar is placed across the output. A crowbar is a latching SCR which is fired when the output is sensed as entering an overvoltage condition. The buckconverter should only be used for board-level regulation.Flyback or Boost-mode Converter FundamentalsThe most elementary flyback-mode converter is the boost or Step-up Converter. Its schematic can be seen in Figure3.2.Its operation can also be broken into two distinct periods where the power switch is on or off. When power switch turns on, the input voltage source is placed directly across the inductor. This causes the current to begin linearly ramping upwards from zero and is described by:()in on L on V t i L ⨯=Once again, energy is being stored during each cycle times the frequency of operation must b higher than the power demands of the load or,20.5sto pkop out P L I f P =⨯⨯>The power switch then turns off and the inductor voltage flies back abovethe input voltage and is clamped and is clamed by the rectifier at the output voltage .The current then begins to linearly ramp downward until the until the energy within the core is completely depleted. Its waveform which is shown in Figure 3.3 is determined by:()()out in offL off V V t i L -⨯=The boost converter should also be only used for board-level regulation.1.3 TopologiesA topology is the arrangement of the power devices and their magnetic elements. Each topology has its own merits within certain applications. Some of the factors which determine the suitability of a particular topology to a certain application are:1) Is the topology electrically isolated from the input to the output or not.2) How much of the input voltage is placed across the inductor or transformer.3) What is the peakcurrent flowing through the power semiconductors.4) Are multiple outputs required.5) How much voltage appears across the power semiconductors.The first choice that faces the designer is whether to have input to output transformer isolation. Non-isolated switching power supplies are typically used for board-level regulation where a dielectric barrier is provided elsewhere within the system. Non-isolated topologies should also be used where the possibility of a failure does not connect the input power source to the fragile load circuitry. Transformer isolation should be used in all other situations. Associated with that is the need for multiple output voltages. Transformers provide an easy method for adding additional output voltage to the switching power supply. The companies building their own power systems are leaning toward transformer isolation in as many power supplies as possible since it prevents a domino effect during failure conditions.1 开关电源除了那些用电池做电源的电子产品外,每个新型电子产品都需要将115V或者230V 的交流电源转换为直流电源,为电路供电。
电力电子英文作文
电力电子英文作文Electric power electronics is a fascinating field that deals with the conversion and control of electrical power. It involves the use of electronic devices to convert and control the flow of electrical energy, which is essentialin various applications such as power supplies, renewable energy systems, electric vehicles, and industrial automation.One of the key components in power electronics is the power semiconductor devices, such as diodes, transistors, and thyristors. These devices are used to switch, regulate, and control the flow of electrical energy in different electronic circuits. They play a crucial role in the efficiency and performance of power electronic systems.Power electronic systems are widely used in modern society, from everyday appliances like refrigerators andair conditioners to industrial equipment and renewable energy systems. They are essential for converting andcontrolling electrical power to meet the diverse needs of different applications.The development of power electronics has led to significant advancements in energy efficiency and renewable energy integration. It has enabled the efficient conversion of electrical power from renewable sources such as solar and wind, making them more viable alternatives totraditional fossil fuels.The future of power electronics looks promising, with ongoing research and development aimed at improving efficiency, reducing costs, and expanding the capabilities of power electronic systems. As technology continues to evolve, power electronics will play an increasingly important role in shaping the future of energy management and sustainability.。
- 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)。
模拟神经网络的动态学习模拟电子电路摘要:在神经网络领域,许多应用模型已经提出了。
一个神经芯片和一个人工视网膜芯片的开发,以包括生物医学视觉系统的神经网络模型及其仿真。
以前的模拟神经网络模型的运算放大器和固定电阻。
改变连接系数是很困难的。
在这项研究中,我们用模拟电子多路电路。
连接权重描述输入电压。
改变连接系数很容易。
该模型的工作原理只有模拟电路。
它可以完成学习过程中的一个非常时间短,这种模式将使更灵活的学习。
关键词:电子电路,神经网络,模拟电子1.简介:我们提出透过利用模拟神经电路进行神经网络的动态学习。
这种模式会发展出一个包括模拟神经电路的全新的信号装置。
其中一个研究目标是生物医学神经功能的建模。
在神经网络领域中,许多应用模型已被提出,而且有许多硬件模型已经实现了。
这些模拟神经网络模型,是由operational amplifier及fixed resistance 所组成的‧这是个非常困难去改变这个连接系数的(指operational amplifier及fixed resistance)1.1模拟神经网络模拟神经网络是通过电压,电流或电荷的连续数量来表达的。
而其最主要的优点是它不但可以透过时钟操作去建造连续时间系统,还可以建造离散时间系统。
明显地actual neuron cell是模拟工作。
使用模拟方法去模仿神经元细胞的运作是可行的。
许多人工神经网络LSI就是用analog method来设计的。
很多processing units可以安装在single-chip上,因为每一个单元都可以由小数量的元件,加法,乘法,以及非线性变换来实现。
还有使用super parallel calculation来操作是可行的。
结论是,与神经网络算法相比高速工作是有其的好处的。
在纯模拟电路中,最大的问题是奴何去实现模拟内存及如何记住模拟量。
到目前为止也还没找到相应的解决方法。
DRAM method是一些记录存在电容器的临时存储,因为它可以与CMOS processs通用。
然而,当数据值保持长期的,也需要一个数字记忆。
在这种情况下,我和一个一个/数转换使得开销问题。
其他记忆方法的浮力门式装置,铁电存储器(FeRAM)和磁性物质的记忆(MRAM)提出了另一种硬件神经网络模型。
它是利用脉冲神经网络。
该模型具有良好的优势。
特别是这个网络可以保持学习过程中的连接权值。
然而,它需要很长的时间学习过程中,需要许多脉冲[7]。
在这项研究中,我们使用了多个电路。
连接权重描述输入电压。
改变连接系数很容易。
这个模型只适用模拟电路。
它可以在很短的时间内完成学习过程这种模式将允许更灵活的学习。
最近,许多研究人员已经专注于半导体集成产业。
特别是低电功率,价格低,规模大,是很重要的。
神经网络模型解释生物医学神经系统。
神经网络具有灵活的学习能力。
许多研究人员模拟了使用电子的生物医学脑神经元的结构电路和软件。
1.2概述神经网络研究的结果,是反馈到神经科学领域。
这些研究领域得到了广泛的发展。
神经网络学习能力接近人类的机制。
因此,有可能使一个更好的信息处理系统,匹配计算机模型的优点和生物医学脑模型。
神经网络的结构通常由三层,输入层,中间层和输出层。
每一层由连接重量和单位。
神经网络是由三层组成的结合神经细胞结构[8][9]。
在神经网络领域,许多应用方法和硬件模型已经提出。
神经芯片和人工视网膜芯片的开发包括神经网络模型和模拟生物医学视觉系统。
在这研究中,我们增加了运算放大器的电路。
连接重量显示增加电路的输入电压。
在以前的硬件模型神经网络,连接权重的变化是困难的,因为这些模型采用电阻元件作为连接权值。
此外,该模型使用的电容器作为连接的权重是提出了。
然而,它是很难调整连接权重。
在本研究中,我们提出了神经网络使用模拟多个电路。
连接的权重显示为多个电路的电压。
它可以改变连接的权重很容易。
学习过程会更快。
起初我们做了一个神经网络计算机程序和神经回路的SPICE模拟。
SPICE指的是电路。
下一章的电路仿真。
接下来我们测量的行为计算机计算与香料模拟的确认。
我们比较了这两种输出结果,证实了一定程度上的遗留行为[10]。
图1。
使用运算放大器的多个电路图2。
神经回路(输入和输出)2.SPICE在本研究中,我们使用的电路模拟器SPICE。
电路模拟器(SPICE)是模拟程序与集成圆的简称重点。
它可以再现电路和电气的模拟运算电路。
在绘制电路CAD,设置输入电压。
香料具有交流的功能,直流暂态分析。
首先,我们做的差分放大器电路和吉尔伯特乘法器电路。
我们确认电压运行良好的范围。
图3。
神经回路实验结果图4。
三层神经回路的结构由运算放大器组成的多个电路的神经元结构为实现乘法功能,电流镜电路实现非线性函数和差分放大器电路。
我们的多个电路图。
在以往的神经网络模型中,我们采用了电阻元件作为一个连接的重量。
但是,它是很难改变的阻力值。
在神经连接,它计算出产品的输入值和连接重量。
我们用多回路作连接的重量。
多回路的每一个输入指输入值和连接权。
连接重量可以显示电压值,很容易在神经网络学习阶段的变化值。
图2为2输入的神经回路,一个输出的输出一个神经元的特性,利用电流增加电流镜电路,产品输入信号和连接权值。
图3为输出特性SPICE仿真。
我们确认时的电压范围之间-0.35V这个电路的正常运行和0.43V达到峰值。
连接的权重和阈值是能够改变的控制在多个电路中的电压。
学习过程会比较容易。
3.三层神经网络我们构建了一三层神经网络,输入层,中间层和输出层。
有2个输入单元,2个中间单元和一个输出单元。
我们结合前一章中描述的神经单元。
图5。
三层神经回路的实验结果在图4中,我们展示了方框图。
这意味着一般的神经网络模型。
但它采用多回路,易于改变连接重量。
“多”指多个电路和“添加”装置的加法电路图4。
实验结果如图5所示。
我们确认时的电压范围之间-0.05v这个电路的正常运行和0.15V。
线性图是中间层的输出而非线性图是图5中最后一层的输出[11]。
在中间层,我们得到了良好的输出信号。
在输出层中,我们得到了小变形信号。
然而,这将不会出现一个显着的问题,在神经网络的输出。
图6。
模拟神经网络的学习阶段4动态学习模型我们提出了使用纯模拟电路的动态学习模型。
我们用模拟神经网络,在前一章中说明。
在学习阶段,我们模拟反馈电路。
图7。
模拟神经网络的工作阶段我们使用一个单独的神经网络的每个教学信号。
实时学习可能的。
在工作阶段,我们使用了采样保持电路。
它可以保持连接权重。
在工作阶段,这个神经网络正在工作。
该电路可以使期刊工作,学习模式和工作模式。
在图6中,我们展示了学习阶段。
“多”是指多个电路,“加”的意思附加电路和“子”是指减法电路。
在图7中,我们展示了工作模拟神经网络。
从上部到下部的空箭头线在图7中,表示固定值的采样保持电路。
它可以保持连接的重量。
有两个输入线,表示在图6和图7。
然而,X1和X2是每个学习模式。
这些都是简化的数字,显示了一个输入信号和2种学习模式。
5结论我们构建了一三层神经网络,2个输入层,2个中间层和一个输出层。
我们证实了三层模拟神经网络的运作用乘法电路的香料模拟。
通过控制输入电压可以改变连接权。
该模型具有非常高的灵活性特点。
当模拟神经网络操作时,突触的重量尤其重要。
它是如何给突触这个神经网络的重量。
要解决这个问题,就必须应用反向传播规律是一种通用的学习规则的方法电子电路。
如果学习是可能的,在神经回路,学习速度将快速。
实现动态学习。
方法是计算输出电压与输出电压的差值差分电路的教学信号。
和反馈的差异值变连接权。
它将提高人工智能元素自主学习。
一个集成设备的实现将使减少的元素数目。
该模型的鲁棒性与故障公差。
未来的任务是系统建设和安装一个大型整合。
参考文献:1。
米德,C:模拟集成电路和神经系统。
阿迪生韦斯利出版公司,公司,阅读(1989)2。
冲,CP,Salama,C.A.T.,史密斯,K.C.:使用VLSI图像运动检测。
IEEE 固态电路杂志27(1),96(1992)93–3。
路,Z市,成为:子像素分辨率的双目视觉跟踪的模拟集成电路视觉传感器。
IEEE电路与系统汇刊II:模拟和数字信号处理47(12),1468-1475(2000)4。
Saito T.,稻,H:一个简单的A/D转换器捕获窗口分析。
在:IEEE国际年。
电路系统,1293页–1305(2003)5。
luthon,F,dragomirescu,D:蜂窝模拟网络基于MRF的视频运动检测。
IEEE 电路与系统-我:基本理论应用程序46(2),281-293(1999)6。
山田,H.,著,T.,大谷,M.,yonezu,H:模拟MOS电路的启发生产移动边缘信号的视网膜内层,IEICE技术报告,nc99-112,pp.149–155(2000)7。
奥田,T,S,好了,石田,M.:实现反向传播学习脉冲基于δ-差调制的神经网络及其硬件实现icice交易j88-d-ii-4–788,778(2005)8。
川口,M.,吉姆,T.梅野,M.:运动检测人造视网膜模型二维多层次模拟电子电路。
e86-a IEICE交易—2,387-395(2003)9。
川口,M.,吉姆,T.梅野,M.:先进的图像模拟集成电路版图设计人工视觉模型的处理。
在IEEE工业国际研讨会电子、议2005出发,3卷,1239页–1244(2005)10。
川口,M.,吉姆,T.,石井,N.:模拟集成电路版图设计和电路板人工视觉模型中的先进图像处理技术。
在洛夫历克,I.豪利特,R.J.,耆那教,LC(主编)KES 2008,第II部分。
LNCS(lnai),卷5178,页895–902。
施普林格出版社,海德堡(2008)11。
川口,M.,吉姆,T.梅野,M.:通过模拟神经网络的动态学习电子电路。
在智能系统研讨会,风扇2010,卷s3-4-3(2010)。