电力电子技术英文版 chapter05

PowerElectronicsPowerElectronicsChapter5DCtoDCConverters(Choppers)PowerElectronics2OutlineOutline5.15.1BasicDCtoDCconvertersBasicDCtoDCconverters5.25.2CompositeDC/DCconvertersandCompositeDC/DCconvertersandconnectionofmultipleDC/DCconvertersconnectionofmultipleDC/DCconverters5.35.3IsolatedDCtoDCconvertersIsolatedDCtoDCconverters(IndirectDC(IndirectDCtoDCconverters)toDCconverters)PowerElectronics35.15.1BasicDCtoDCconvertersBasicDCtoDCconverters5.1.1Buckconverter(Step5.1.1Buckconverter(Step--downconverter)downconverter)5.1.2Boostconverter(Step5.1.2Boostconverter(Step--upconverter)upconverter)5.1.3Buck5.1.3Buck--Boostconverter(StepBoostconverter(Step--down/stepdown/step--upconverter)andupconverter)andCukCukconverterconverter5.1.45.1.4SepicSepicconverterandZetaconverterconverterandZetaconverterPartoftheslidesofthissectionistakenandmodifiedfrom:R.EricksonandD.Maksimovic.FundamentalsofPowerElectronics.KluwerAcademicPublishers,2001PowerElectronics45.1BasicDCtoDCconverters5.1BasicDCtoDCconvertersIntroductionIntroduction——BuckconverterBuckconverterSPDTswitchchangesSPDTswitchchangesdccomponentdccomponentSwitchoutputSwitchoutputvoltagewaveformvoltagewaveformDutycycleD:DutycycleD:00≤≤DD≤≤11complementD’:D’=1-DPowerElectronics5DccomponentofswitchoutputvoltageDccomponentofswitchoutputvoltageFourieranalysis:Dccomponent=averagevaluePowerElectronics6InsertionoflowInsertionoflow--passfiltertoremoveswitchingpassfiltertoremoveswitchingharmonicsandpassonlydccomponentharmonicsandpassonlydccomponentPowerElectronics7BasicoperationprincipleofbuckconverterBasicoperationprincipleofbuckconverterBuckconverterBuckconverterwithidealswitchwithidealswitchRealizationRealizationusingpowerusingpowerMOSFETandMOSFETanddiodediodePowerElectronics8ThoughtprocessinanalyzingbasicThoughtprocessinanalyzingbasicDC/DCconvertersDC/DCconvertersBasicoperationprinciple(qualitativeanalysis)Basicoperationprinciple(qualitativeanalysis)––HowdoescurrentflowduringdifferentswitchingstatesHowdoescurrentflowduringdifferentswitchingstates––HowisenergytransferredduringdifferentswitchingstatesHowisenergytransferredduringdifferentswitchingstatesVerificationofsmallrippleapproximationVerificationofsmallrippleapproximationDerivationofinductorvoltagewaveformorcapacitorDerivationofinductorvoltagewaveformorcapacitorcurrentcurrentwaveformduringwaveformduringdifferentswitchingstatesdifferentswitchingstatesQuantitativeanalysisaccordingtoinductorvoltQuantitativeanalysisaccordingtoinductorvolt--secondsecondbalanceorcapacitorchargebalancebalanceorcapacitorchargebalancePowerElectronics9ActualoutputvoltagewaveformofbuckconverterBuckconverterBuckconvertercontainingpracticalcontainingpracticallowlow--passfilterpassfilterActualoutputvoltageActualoutputvoltagewaveformwaveformvv((tt)=)=VV++vvrippleripple((tt))PowerElectronics10ThesmallrippleapproximationThesmallrippleapproximationvv((tt)=)=VV++vvrippleripple((tt))InawellInawell--designedconverter,theoutputvoltagedesignedconverter,theoutputvoltagerippleissmall.Hence,thewaveformscanberippleissmall.Hence,thewaveformscanbeeasilydeterminedbyignoringtheripple:easilydeterminedbyignoringtheripple:PowerElectronics11Buckconverteranalysis:Buckconverteranalysis:inductorcurrentwaveforminductorcurrentwaveformPowerElectronics12InductorvoltageandcurrentInductorvoltageandcurrentsubinterval1:switchinposition1subinterval1:switchinposition1PowerElectronics13InductorvoltageandcurrentInductorvoltageandcurrentsubinterval2:switchinposition2subinterval2:switchinposition2PowerElectronics14InductorvoltageandcurrentwaveformsInductorvoltageandcurrentwaveformsPowerElectronics15DeterminationofinductorDeterminationofinductorcurrentripplemagnitudecurrentripplemagnitudePowerElectronics16InductorcurrentwaveformInductorcurrentwaveformduringstartduringstart--uptransientuptransientPowerElectronics17TheprincipleofinductorTheprincipleofinductorvoltvolt--secondbalance:Derivationsecondbalance:DerivationPowerElectronics18InductorvoltInductorvolt--secondbalance:secondbalance:BuckconverterexampleBuckconverterexamplePowerElectronics19TheprincipleofcapacitorchargeTheprincipleofcapacitorchargebalance:Derivationbalance:DerivationPowerElectronics20BoostconverterexampleBoostconverterexamplePowerElectronics21BoostconverteranalysisBoostconverteranalysisPowerElectronics22Subinterval1:switchinposition1Subinterval1:switchinposition1PowerElectronics23Subinterval2:switchinposition2Subinterval2:switchinposition2PowerElectronics24InductorvoltageandcapacitorcurrentInductorvoltageandcapacitorcurrentwaveformswaveformsPowerElectronics25InductorvoltInductorvolt--secondbalancesecondbalancePowerElectronics26ConversionratioConversionratioM(D)M(D)ofoftheboostconvertertheboostconverterPowerElectronics27DeterminationofinductorcurrentDeterminationofinductorcurrentdccomponentdccomponentContinuousContinuous--ConductionConduction--Mode(CCM)andMode(CCM)andDiscontinuousDiscontinuous--ConductionConduction--Mode(DCM)ofbuckMode(DCM)ofbuckEV+-MRLVDioEMuoiGPowerElectronics28ContinuousContinuous--ConductionConduction--Mod