功率电子技术应用要点课件

1、Application Technology of Power Electronics 功 率 电 子 技 术 应 用Application Technique of Power Electronics主 讲：Li Lei职 称：Associate Professor教研室：Power System and Automation电 邮：1Application Technology of Power ElectronicsCourse Characteristics: Professional Course Application Technique Dual-Language 2Applic

2、ation Technology of Power ElectronicsText Book Jai P.Agrawal. Power Electronic Systems-Theory and Design. Beijing:Tsinghua University Press, 2001.3Application Technology of Power ElectronicsReference Books 周志敏，周纪海. 开关电源实用 技术与应用. 北京：人民邮电出 版社，2004. 4考核方式闭卷考试 70%平时成绩 15%Application Technology of Power

3、Electronics实验成绩 15%5Application Technology of Power ElectronicsMain Contents: Bird-eye View of Power Electronics Systems Power Electronic Components Power Electronic Converter Circuits Power Electronic Application Systems 6Chapter 1 Birds-eye View of Power Electronics SystemsObjectives: The overall

4、systems view of power electronic converters. Modeling of elements and systems of power electronic converters. The desired performance characteristics, which include power efficiency, power factor, etc.Application Technology of Power Electronics7Application Technology of Power Electronics1.1 INTROCDU

5、CTION Electric power is the muscle of modern industry. Electric power must be converted to other energy forms for use.8 Power electronics makes the utilization of electric power smarter. The focus in power electronics is on conversion, efficiency of conversion and control of energy. Development of s

6、emiconductor switching devices have contributed very significant for modern power electronics.Application Technology of Power Electronics9 Power Electronics: is the electronics applied to conversion and control of electric power. Range of power scale:milliwatts(mW) megawatts(MW) gigawatts(GW)Applica

7、tion Technology of Power Electronics10Application Technology of Power Electronics11Application Technology of Power Electronics12Application Technology of Power Electronics13Application Technology of Power Electronics14Application Technology of Power Electronics15Application Technology of Power Elect

8、ronics16Application Technology of Power Electronics17Application Technology of Power Electronics18Application Technology of Power Electronics1.2 A Simple Voltage Converter19Application Technology of Power Electronics20Application Technology of Power Electronics21Application Technology of Power Elect

9、ronics22Application Technology of Power ElectronicsD=switching duty cycleTs=switching periodDC component of vs(t)= average value:23Application Technology of Power Electronics24Application Technology of Power Electronics25Application Technology of Power Electronics1.3 Systems View of Power Electronic

10、 ConvertersConversion of Electric Power26Application Technology of Power ElectronicsTypes of electric power27Application Technology of Power Electronics28Applications of inverter: Aircraft and space power supplies Uninterruptible power supplies Variable-frequency ac motor drives Aircraft variable-sp

11、eed constant frequency supplies Induction heating suppliesApplication Technology of Power Electronics29Application Technology of Power ElectronicsApplications of rectifier: DC motor drives Regulated dc power supplies High voltage dc transmission Wind generator converters30Application Technology of P

12、ower ElectronicsApplications of DC Chopper: Electric transportation High performance regulated power supplies Telecommunication power supplies DC motor drive systems31Application Technology of Power ElectronicsApplications of AC to AC converter: Frequency converter Voltage regulators VAR regulators

13、AC motor speed controls Solid-state relays32Application Technology of Power ElectronicsGeneric structure of power electronic system 33Application Technology of Power Electronics341.4 Elements of the Converter Systems: Modeling and AssumptionsApplication Technology of Power Electronics In general, el

14、ements are very complex, nonlinear, time-variant. Elements may be modeled by linear, time- invariant elements if they are used over a smaller time duration, within a limited range of their characteristics.35 Resistance: V=Ri* R is the only energy dissipating element in power electronic systems.Appli

15、cation Technology of Power Electronics36Application Technology of Power Electronics Inductance:* A large inductor may be modeled by a current source over the segment dt.37Application Technology of Power Electronics Capacitance:* A large capacitor may be modeled by a voltage source over the segment d

16、t.38 Sources:SourceVoltage SourceCurrent SourceSourceDC SourceAC SourceApplication Technology of Power ElectronicsDC Voltage SourceDC Current SourceAC Current Source AC Voltage Source39 Voltage Source: Current Source:Application Technology of Power Electronics40Application Technology of Power Electr

17、onics DC Voltage Source: A source provides a voltage of constant amplitude at all times. *A battery is closest to an ideal dc voltage source. DC Current Source: do not exist in nature. *A preenergized large value inductor can be treated as a dc current source.41Application Technology of Power Electr

18、onics AC Voltage Source: A source provides a voltage waveform with periodic variation of amplitude over time. AC Current Source: do not exist in nature. *A practical ac current source can be synthesized from an ac voltage source in series with a large value inductor.42Application Technology of Power

19、 Electronics Electrical Switch: An ideal electrical switch may be defined as following: In the on state, vsw=0 at all amplitudes and waveforms of the current isw In the off state, isw=0 at all amplitudes and waveforms of the voltage vsw43Application Technology of Power Electronicsisw+ vsw_isw+ vsw_i

20、swiswiswvswvswvswONOFFONOFFBidirectional Switch Unidirectional Switch 44Application Technology of Power ElectronicsBidirectional switch synthesized from unidirectional switchesMulti-way switch synthesized from unidirectional switches45Application Technology of Power Electronics Transformer:v111ii2NN

21、2v2A two-winding transformer46 Loads and sinks Electrical loads can be classified in the following categories: Resistive: heaters, ovens and furnaces Inductive: motor, electromagnetic relays Capacitive: displays, gas discharge lamps DC current loads: dc motor in constant torque applicationsApplicati

22、on Technology of Power Electronics47 DC voltage loads: dc motor in constant speed applications, batteries during charging AC voltage loads: ac voltage BUS, induction and synchronous motors in constant speed applications AC current loads: induction and synchronous motors in constant torque applicatio

23、ns Application Technology of Power Electronics48Application Technology of Power Electronics Resistive loads are modeled by pure resistances. The dc current load may be modeled by a dc current sink. The dc voltage load may be modeled by a dc voltage sink.49Application Technology of Power Electronics1

24、.5 Converter Topology Inductor in converter topologynot permitted connectionspermitted connectionsLLIooIIIss50Application Technology of Power ElectronicsIn the steady-state conditions, there is:For a fixed inductance, energy equation is:51Application Technology of Power Electronics Capacitor in conv

25、erter topologynot permitted connectionspermitted connectionsCCVVVVssoo52Application Technology of Power ElectronicsIn the steady-state conditions, there is:For a fixed capacitance, energy equation is:531.6 Converter Operation and Desired characteristics* Converter operation involves the turning on a

26、nd off of switches in a periodic sequence.* Converter operation consists of two phases: the transient phase and the steady-state phase.Application Technology of Power Electronics54Application Technology of Power Electronics Some of the desirable characteristics of the converter operation are: The ou

27、tput voltage (current) should be set to the desired value and waveform. The output voltage (or current) should be insensitive to variations in load, input voltage(or current) and component values. The converter should cause minimum distortion and loading on the source side.55Application Technology o

28、f Power Electronics The output voltage or current should have minimum distortion and minimum number of undesired components. A small range of control parameter should be able to control a large variation in output voltage (or current).56Application Technology of Power Electronics The converter shoul

29、d exhibit minimum power loss and maximum resistance to transients. The converter elements should store minimum energy, even temporarily. 57Application Technology of Power Electronics1.7 Converter Performance Measures* The converter performance consists of the transient and steady state parts.* The t

30、ransient performance measures are: Transient current from the source Short circuit current from the source Surge protection Switch stress58Application Technology of Power ElectronicsSurge protection: Difference between the maximum transient voltage and the nominal output voltage when the power is tu

31、rned on and turned off to the converter. The amount of transient voltage when a large load is switched in or out.59Switch stress: Highest voltage and the highest rate of rise or fall of voltage across the switching device. Highest current and the highest rate of rise or fall of current through the s

32、witching device.Application Technology of Power Electronics60Application Technology of Power Electronics* The steady-state converter performance measures are: Forward transfer characteristics Reflective characteristics Control characteristics Harmonic profile Component stresses61Application Technolo

33、gy of Power Electronics Forward transfer characteristics Voltage transfer ratio: Current transfer ratio:62 Output variable Input variableac-dc converter: average value rms valuedc-ac converter: rms value dc valuedc-dc converter: average value dc valueac-ac converter: rms value rms of the fundamental

34、 harmonic Application Technology of Power Electronics63Application Technology of Power Electronics Reflective characteristics Voltage reflection ratio: Current reflection ratio:64 Control Characteristics It is desirable to have a small variation in the control parameter that would control a large va

35、riation in the output variable.Application Technology of Power Electronics65 Harmonic Profile Harmonic profile is the plot of amplitude versus frequency for the ac waveform of voltage, current or instantaneous power.Application Technology of Power Electronics66 Following measures are used for the harmonic profile:Application Technology of Power Electronics Average Value Root-mean-square(rms) Value Peak-Peak Ripple Lowest Undesired Harmonic Frequency T