翻译高频软开关PWM功率变换技术的发展与现状.docx

翻译高频软开关PWM功率变换技术的发展与现状.docx

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翻译高频软开关PWM功率变换技术的发展与现状

DevelopmentandPresentStatusofHighFrequency

SoftSwitchingPWMPowerConvertingTechniques

ChenDaolianYanYangguang

（NanjingUniversityofAeronautics&Astronautics）

Keywords:

SoftSwitchPWM,ZeroVoltageSwitching,ZeroCurrentSwitching

Abstract:

Recently,powerelectronicsresearchershaveproposedmanysoftswitching

PWMpowerconvertingtechniques,whichcombinedadvantagesofbothconventionalPWMandresonantconverterswhileavoidedtheirrespectivelimitations.Inthispaper,thefeaturesandoperatingprinciplesofthreeclassesofzerovoltagesoftswitchingPWMconverters（zerovoltageswitchingquasisquarewaveconverters,zerovoltageswitchingPWMconverters,andzerovoltagetransitionPWMconverters）andtwoclassesofzerocurrentsoftswitchingPWMconverters（zerocurrentswitchingPWMconvertersandzerocurrenttransitionPWMconverters）areintroduced.

1.INTRODUCTION

Inordertomeettheneedsofsmallsize,lightweight,highefficiencypowersupply,andtheswitchtypepowerconversiontechnologyhasfromthetraditionalPWMconverterdevelopmenttoresonantconverter,quasiresonantconverter,multiresonantconverter.Recently,therehasbeensoftswitchingPWMconverter.ThePWMconverterisusedtoforcetheswitchingmodetointerruptthepowerfluxtotransformpower.Theresultisthatthepulsecurrentandvoltageareformed,andthepowersemiconductordeviceissubjectedtolargevoltageandlargecurrentstress.Theresonantconvertercomprisesaconventionalseriesandparallelresonantconverter,anEconverter,aquasi-resonantconverterandamultiresonantconverter.Powerswitchwithzerovoltageswitching（ZVS）orzerocurrentswitching（ZCS）commutation,switchinglossesandswitchingtransientstressthanthePWMconverterislow.Butresonantconvertersarecirculationcircuitwithhighenergyandsteady-statevoltageandcurrentstressanddeviceloss,ZVSorZCSconditionsonthevariationrangeofthesupplyvoltageorloadsensitive,frequencyofmodefaults,andcircuitdesigndifficulttooptimize.

Recently,powerelectronicsresearchersproposeallkindsbetweenPWMandresonanttechnologyofsoftswitchingPWMtechnique（Soft-Switchingtechniques）,itspurposeliesindoesnotneedtoomuchenergycyclecanachievesoftswitching.Generallyspeaking,softswitchingtechnologyusessomeresonancetechnologytosoftentheswitching,switchingconvertertocompletetheconvertertorestoreitssimilarPWMmode,makingthecircuitoftheminimumcycleenergy.Thus,theswitchinglossisgreatlyreducedinthecasethattheconductionlossisminimized.

2.ZerovoltagesoftswitchingPWMtransformtechnology

ManystudieshaveshownthatusingpowerMOSFETasthepowerswitchofthehighfrequencypowerconversion,ZVSisthepreferredmodeofoperation.

2.1ZVSquasisquarewaveconverter（ZVS-QSC）[1]

ZVS-QSCswitchasshowninFigure1,Sbasedswitches,S1fortheauxiliaryswitch,CrfortheabsorptionoftheSandS1outputcapacitors,Lbothfilteringandharmonicdualfunction.InordertoobtainS1,ZVScanbeapassiveswitchdiodeoranactiveswitch.IftheS1isimplementedbythediode,thentheZVS-QSCwillworkinthecriticalconductionmodePWMconverter,inordertoobtaintheZVSneedtofixtheinputandoutputconditions.Whentheinputvoltageorloadcurrentischanged,thedutycycleandtheswitchingfrequencyareadjustedinordertomaintaintheoutputstabilityandtheZVScondition.However,ifS1bytheactiveswitchtoachieve,thenZVS-QSCcanworkintheconstantfrequencymode,andinthepowersupplyandloadvariationrangetoobtainZVS.

Figure1ZVS-QSCswitch

WithZVS-QSCswitchtoreplacethebasicPWMconverterPWMswitchingcanbederivedasanexampleofafamilyofZVS-QSC,BuckZVS-QSCconverterandtheprincipleofwaveformasshowninFigure2,thecircuitwithbidirectionalpowerflowandapplicationinbi-directionalpowerconversionapplicationssuchasbatterycharge/dischargeoccasions.

ZVS-QSCrealizethe2transistorsZVS,switchingvoltagestressisminimum,toachievetwo-waypowerflow.Butithasdisadvantagessuchaslargetransistorpeakcurrent,largeinputandoutputcurrentripple,andtransformerleakageinductance,whichisnotsuitableforIGBT,BJT,GTOandothersmallpowerdevices.

Figure2ZVS-QSCBuckcircuitanditsprinciplewaveform

2.2ZerovoltageswitchingPWMconverter

ZVS-PWMconvertercanbeasZVS-QRC（zerovoltageswitchingquasiresonantconverterandthePWMconverter,hybridcircuitinZVS-QRCswitchinbothendsoftheresonantinductoraddanauxiliaryswitchcanbeobtainedZVS-PWMswitch,asshowninFigure3（a）shows.TheauxiliaryswitchS1byshortcircuitresonantinductanceLrperiodicallyeliminatecircuitresonance,eachcycleisonlyashorttimeresonancephenomenon,thisisonlyusedtocreateconditionsforZVSpowerswitch.PassthetimebycontrollingtheS1guidecanbeobtainedworkingfrequency.

Figure3ZerovoltageandzerocurrentswitchingPWM

ReplacePWMswitchPWMconverterwiththeZVS-PWMswitch,itisderivedfromafamilyofZVS-PWMconverters.Figure4showstheZVS-PWMBuckconvertercircuitandtheprincipleofwaveform.ThepowerswitchtoachievetheZVS,thecurrentstressissmall,butthevoltagestress（loadrangeproportional）,rectifierdiodedoesnotworkinthesoftswitchingcondition,ZVSconditionofinputvoltageandloadvariationsensitivity.

Figure4ZVS-PWMBuckconverteranditsprincipleofwaveform

2.3ZerovoltageswitchingPWMconverter

Resonantconverter（includingZVS-PWMandZCS-PWM）arecommonfeaturesofshapingthevoltageandcurrentwaveformsusingtheresonantinductor,theresonancebetweentheresonantinductorandresonantcapacitortoachievesoftswitching.Becausetheresonantelementsarelocatedinthemainpowerchannel,soithasthefollowingproblems:

Resonantinductanceunderbidirectionalvoltage,inevitablyproduceadditionalvoltagestressappliedinsemiconductordevices;allthepowerflowtoproducehighcirculatingenergythroughtheresonantinductor,greatlyincreasedtheconductionlosses;resonantinductancestoredenergyandthepowersupplyvoltageandloadflowiscloselyrelatedto,sosoftswitchingconditionsofsupplyvoltageandloadcurrentissensitivetothechangeofthe,whichiswhymostresonantconverterinawidepowersupplyvoltageandloadrangeisdifficulttomaintainthefundamentalcauseofthesoftswitch.

Inordertoovercometheseshortcomings,itisnecessarytoresonantsensorisremovedfromthemainchannel,thepowerswitchisconnectedinparallelwitharesonantnetworkisreplacedseriesresonantelement,switchingduringparallelresonantnetworkresonantZVSorZCSandswitchaftertheendofthecircuitandtorestorethesimilartoPWMmode.ThisapproachmakestheconvertertoobtainbothPWMconverterhastheadvantagesofsoftswitching.ZVS-PWMandzerocurrentswitchingPWMconverter（ZCT-PWM）istheuseoftheconceptoftheparallelresonantnetwork.

TheparallelresonantnetworkinPWMswitchisthederivationofZVT-PWMswitch,asshowninFigure5（a）shows.ThisistheresonantnetworkbytheresonantinductanceLr,auxiliaryswitchS1andthediodeD1,Crisabsorbedbytheresonantcapacitorswitchingpoweroutputcapacitoranddiodejunctioncapacitance.ReplacingthePWMswitchwithZVT-PWMswitchescanbederivedfromthegensZVT-PWMconverterduetoresonantnetworkandthepowerswitchareconnectedinparallel,theZVT-PWMcanmakethetransistoranddiodevoltageandcurrentshouldbeminimalforceobtainedundersoftswitching.ThisisthePWMconverterwithsoftswitchingstressconditionisputforwardforthefirsttimeinnoadditionalswitchingvoltageandcurrenttechnology.

Figure5Zerovoltageswitchingandzerocurrentswitch

ZVT-PWMBoostconvertercircuitanditsprincipleofwaveformasshowninFigure6.Crystaltriodeanddioderectifieraresoftswitching,switchingvoltage,currentshouldbeminimumforce,thepowersupplyvoltageandloadrangecanachievesoftswitching;butZVT-PWMtechnologydifficulttoabsorbtransformerleakageinductance（similartotheZVS-QSC）assistedswitchishardswitch.

Figure6ZVT-PWMBoostconverterandtheprincipleofwaveform

TheswitchlossofauxiliaryresonantcircuitthanPWMconverterswitchinglossismuchlower.First,ZVT-PWMconverter,theswitchinglossisthecapacitanceoftheauxiliaryswitchS1turn-onloss,itisnecessarytothancapacitivePWMconvertermainswitchturn-onlossismuchlower,becauseS1onlywithmuchlowereffectivecurrentvalue,soyoucanusethelowoutputcapacitanceofsmallcapacityMOSFETdevicesasS1.IfS1isusedtoachieveMOSFET,becauseofitsgatedriveimpedanceisverylow,sotheS1turnofflossisnegligible.Secondly,ZVT-PWMconverterauxiliarydiodealwaysworkinginZCS,thuseliminatingtheproblemofseriousreverserecovery.However,PWMconverterrectifierdiodereverserecoverylossaccountedforthetotallossoftheswitch,sotheZVT-PWMtechnologyisespeciallysuitableforhighoutputapplications.

3.ZerocurrentsoftswitchingPWMconverter

DuetotheIGBTswitchingcharacteristicsofcontinuousimprovement,lowconductionlossandprice,ithasbeenappliedintheconverterandinverterswitchingpowerconverteriswidelyusedinthe.BecauseIGBTislessloaddevice,turnofftheperformanceofthecurrenttailingphenomenonhasresultedinaconsiderablelossoff.InordertomakeIGBTworkinarelativelyhighswitchingfrequency,ZVSorZCStechnologycanbeusedtoreducetheswitchingloss.Ingeneral,ZVSeliminatesthecapacitiveturn-onloss,byslowingtherateofvoltageriserateandreducetheoverlaptime