電力電子技術(shù)Chapter0課件1

1、OutlineWhat is power electronics?The historyApplicationsA simple exampleAbout this courseWhat is power electronics?DefinitionRelation with information electronicsThe interdisciplinary naturePosition and significance in the human societyPower Electronics: A more exact explanation: is the electronics

2、applied to conversion and control of electric power. Range of power scale : milliwatts(mW) megawatts(MW) gigawatts(GW)Definition The primary task of power electronics is to process and control the flow of electric energy by supplying voltages and currents in a form that is optimally suited for user

3、loads.Conversion of electric powerOther names for electric power converter: -Power converter -Converter -Switching converter -Power electronic circuit -Power electronic converterElectric PowerConverterPoweroutputPower inputControl inputFrequency, magnitude, number of phasesAC (Alternating Current)Ma

4、gnitudeDC(Direct Current)Changeable properties in conversion Two types of electric powerClassification of power convertersDCACACAC to DC converter (Rectifier)AC to AC converter ( Fixed frequency : AC controller Variable frequency: Cycloconverter or frequency converter) DCDC to DC converter (Chopper)

5、 DC to AC converter (Inverter)Power outputPower inputPower electronic systemGeneric structure of a power electronic systemPower ConverterPower outputPower inputControllerFeedforward/FeedbackFeedback/FeedforwardReference(commanding) ( measurements of output signals ) ( measurements of input signals )

6、 Control is invariably required. Power converter along with its controller including the corresponding measurement and interface circuits, is also called power electronic system.Control inputTypical power sources and loads for a power electronic systemThe task of power electronics has been recently

7、extended to also ensuring the currents and power consumed by power converters and loads to meet the requirement of electric energy sources.-Electric Motor-light-heating-power converter -other electric or electronic equipment Power ConverterSourcePower inputPower outputLoadControllerReference-Electri

8、c utility-battery-other electric energy source -power converterFeedback/Feed forwardA Classification of electronics by processing objectRelation with information electronicsElectronicsInformation electronics: to process information Power electronics: to process electric power Other classifications o

9、f electronicsElectronicsVacuum electronics: using vacuum devices, e.g, vacuum tubes devicesSolid (Solid state) electronics: using solid state devices, e.g, semiconductor devicesElectronicsApplied electronics: application of electronic devices to various areas Physical electronics: physics,material,f

10、abrication, and manufacturing of electronic devicesThe interdisciplinary natureWilliam E. Newells description ElectronicsDevices,circuitsPower Static & rotating power equipmentPower ElectronicsContinuous, discrete ControlPower electronics is the interface between electronics and power.Relation with

11、multiple disciplines Power electronics is currently the most active discipline in electric power engineering worldwide. PowerelectronicsSystems & Control theoryCircuit theorySignal processing Simulation & computingElectronicsSolid state physicsElectromagneticsPower systemsElectric machinesPosition a

12、nd significance in the human society Electric power is used in almost every aspect and everywhere of modern human society.Electric power is the major form of energy source used in modern human society.The objective of power electronics is exactly about how to use electric power, and how to use it ef

13、fectively and efficiently, and how to improve the quality and utilization of electric power.Power electronics and information electronics make two poles of modern technology and human society information electronics is the brain,and power electronics is the muscle.The historyThe thread of the power

14、electronics history precisely follows and matches the break-through and evolution of power electronic deviceslate 1980smid 1970s19571900Mercury arc rectifier Vacuum-tube rectifier Thyratron Invention of ThyristorPower diode ThyristorApplication of fast-switching fully-controlled semiconductor device

15、sGTOGTRPower MOSFET Thyristor(microprocessor)IGBTPower MOSFETThyristor(DSP)Pre-history1st phase2nd phase3rd phaseApplicationsIndustrialTransportationUtility systemsPower supplies for all kinds of electronic equipmentResidential and home appliancesSpace technologyOther applicationsIndustrial applicat

16、ionsMotor drivesElectrolysisElectroplatingInduction heatingWeldingArc furnaces and ovensLightingTransportation applicationsTrains & locomotivesSubwaysTrolley busesMagnetic levitationElectric vehiclesAutomotive electronicsShip power systemsAircraft power systemsUtility systems applicationsHigh-voltag

17、e dc transmission(HVDC)Flexible ac transmission(FACTS)Static var compensation & harmonics suppression: TCR, TSC, SVG, APFCustom power & power quality controlSupplemental energy sources : wind, photovoltaic, fuel cellsEnergy storage systemsPower supplies for electronic equipmentTelecommunicationsComp

18、utersOffice equipmentElectronic instrumentsPortable or mobile electronicsservercomputerTelecommunicationResidential and home appliancesLightingHeatingAir conditioningRefrigeration & freezersCookingCleaningEntertainingApplications in space technologySpaceship power systemsSatellite power systemsSpace

19、 vehicle power systemsOther applicationsNuclear reactor controlPower systems for particle acceleratorsEnvironmental engineeringTrendsIt is estimated that in developed countries now 60% of the electric energy goes through some kind of power electronics converters before it is finally used. reduction

20、of energy consumption leads to less pollution reduction of pollution produced by power converters direct applications to environment protection technology Power electronics has been making major contributions to: -better performance of power supplies and better control of electric equipment -energy

21、saving -environment protectionA simple example A simple dc-dc converter exampleInput source:100VOutput load:50V, 10A, 500WHow can this converter be realized?Dissipative realizationResistive voltage dividerDissipative realizationSeries pass regulator: transistor operates in active regionUse of a SPDT

22、 switchSPDT: Single pole double throwThe switch changes the dc voltage levelAddition of low pass filterAddition of (ideally lossless) L-C low-pass filter, for removal of switching harmonics: Choose filter cutoff frequency f0 much smaller than switching frequency fs This circuit is known as the “buck converter”Addition of control system for regulation of output voltageMajor issue