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Simulation with Ideal Switch Models Combined with Measured Loss Data Provides a Good Estimate of Power Loss

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Simulation with Ideal Switch Models Combined with Measured Loss Data Provides a Good Estimate of Power Loss

    Simulation with Ideal Switch Models

    Combined with Measured Loss Data

    Provides a Good Estimate of Power Loss 41卷第8

    20078

    电力电子技术

    PowetElectronics

    V01.41.No.8

    August,2007

    SimulationwithIdealSwitchModelsCombined

    withMeasuredLossDItItaProvidesaGoodEstimateofPowerLoss

    StigMunkNielsen.LucianNTutelea2,UlrikJager3

    (1AalborgUnivers,Pontoppidanstraede101,DK-9220AalborgEast,Denmark; 2.Timisoara"Politehnica"University,VasileParvan2,Timisoara1900,Romania; 3.DanfossDrivesA/S,DK6300Graasten,Denma~)

    Abstract:ldeany.converterlossesshouldbedeterminedwithoutusingallexcessiveamountofsimulationtime.State-of-the-anpowersemiconductor

    modelsprovidegoodaccuracy.unfortunatelytheyoftenrequireaverylongsimulationtime.rhipaperdescribeshowtoestimatepowerlossesfrom

    simulationusingidealswitchescombinedwithmeasuredpowerlossdata.Thesemiconductorbehaviorisputintoalo0k-uptable.whichreplacesthe

    advancedsemiconductormodelsandshortensthesimulationtime.Toextractswitchingandconductionlosses,aconverterissimulatedandthesemiconductor

    powerlossesareestimated.Measurementresultsonalaboratoryconverterarecomparedwiththeestimatedlossesandagoodagreementisshown.Usingthe

    idealswitchsimulationandthepostprocessingpowerestimationprogram,atentotwentyfold

increaseinsimulationspeedisobtained,comparedto

    simulationsusingadvancedmodelsofsemiconductors.

    Keywords:converter;loss;powersemiconductordevice

    中图分类号:TM46文献标识码:A文章编号:1000100X(2007)08-0107-04

    1Introduction

    Whendesigningpowerelectronicconverters,thereareseveralreasons whyitisimportanttoknowthepowerdissipationofthesemiconductors.A goodestimationofthepowerdissipationenablesthepredictionofconverter efficiency,whichisusedintheevaluationofdifferentconverterdesigns.An exampleistheapplicationofpowerelectronicsinair-conditioning,where anefficiencygainofoneortwopercentresultsinasignificantlyreduction inthecostofownership.Usingthetraditionalthree-phaseinverterbridge, newimproveddevicesdecreasethepowerloss,whichenablesasmaller heatsinkorlargerpowerrating.Anestimationofpowerlossisusefultothe designerinminimizingmaterialcostsandsize.Accurateestimationofthe semiconductorsthermalstressatdifferentoperationconditionscanbeused inprotectionstrategiestoavoidexcessivethermalstress.Alargenumberof newdevicesarepresentedonthemarketandimplementingthedevicesina converterandevaluatingtheperformanceinmanydifferentworkpointscan rapidlybecomealloverwhelmingtask.

    Tomakeanaccurateestimationofthesemiconductorlosses,state. of-the?artsimulationmodelsmaybeused.Asimplemodeldescribing

    thesemiconductorwithavoltagesourcedmpandaresistorisusefulin determiningtheconductionlossesbutnotsuitedtoestimatingthe switchinglosses.

    Largetimeconstantdifferencesoftenoccurinpowerelectronicp? plications,suchasdrives.Hence,thesimulationofafewseconds'real timeisunrealisticallylongandtroublesome.Manydifferentmethodsale availabletoestimatethesemiconductorlosses13-.61.Hereamethodispre. sentedwhichincludesasimplemodelandparameterextractionmethod.

Finally,avalidationandadiscussionarecarriedout.

    2PowerIossEstimation--TheMethodDescription

    Amethodtocomputethepowerdevicelossesisproposedinthis paper.TheblockdiagramoftheproposedmethodisshowninFig.1.A high?speedsimulationbydedicatedsoftware(PSIM,SABER,or PSPICE)andanidealmodelofpowerdevicesareusedtoproducevolt? ageandcurrenttimedependenceofthepowerdevices.Apostpmces~r programusingalook?uptablecontainingswitchingenergylossdepen? denceonvoltage,currentandjunctiontemperatureandon?statevoltage dependenceversuscurrentandjunctiontemperature,cancomputethe devicelosses.Thetransistortum?onenergyloss,,turn?offenergyloss, E.anddiodeturn-offenergyEversusd.c.voltagelevel.Vkcollector current,,junctiontemperature,,andgateresistance,Rg,areobtained fromdatasheetsortheyre?

    suhfromdynamictestsof

    powerdevices.Thetransistor

    on?statevoltagedropV

    versust,andandalso

    diodeforwardvoltagedrop

    Vfversusdiodeforwardcur-

    rent,^,anddiodejunction,

    ,areobtainedfromdata

    sheetsorfromstaticpower

    devicestests.Finally.the

    transistorpowerlosses,,

    anddiodepowerlosses,,

    alecomputedversusswitch?

    ingfrequency.

    Dynamictests:

Fc,g?/c,/iwaves

    Statictests:

    (,,)

    l=,(,r,)

    Datasheet

    Parameters

    Iock.iiPtabIe

    Eoni,(1ac,J

    E0ffi^lc,/ctJ

    Ed0ff-/(c,tJ

    PSIM.SABER.

    PSPlCE

    Simulationusing

    idea1modeIs

    I,),/c=AI)

    Postprocessor

    R),Pd,

    Fig.1Powerdeviceslossestimation?the

    blockdiagram

    3DeterminationofParnforLook.Up.Table

    Withsimplemeasurements,turn-on,turn?offandconductionenergy lossesCanbedetermined.Insomecasesturn.onandturn.offlossesvailbe obtainedfromdatasheets.Theexperimentcarriedoutinthelaboratorymay besimulatedusingtheaccurateadvancedmodels.TheIGBTanddiode turn?onandturn?offlossesalemeasuredfordifferentconditions.appendix 1,usingthetestsystemdescribedin7-9].Withthesemiautomatictestset- up,themeasurementanddataextractionrequiretwodays. ThedoublepulseprincipleofthedynamictestisshowninFig.2. Twoshortpulsesareappliedatthegateemitterterminalsof.Thegate emittervoltage,V,thecollectoremittervoltageV.andcurrentare

recordedusingafourchanneloscilloscope.RecordedVandt

    waveformsduringtransientturn?on

    regimeareshowninFig.3a,and

    turn?offregimeinFig.3b.

    Theoretically,thepowerand

    energylossesduringtheswitching

    regimealeverysimpletocompute.

    Thetam?onpowerloss,P,andFig-2Dynamictestontransistor turn?onenergylosscomputationisshownin(1).Similarequationsale

    alsousedtofindtum?offpowerandenergylosses: r

    (?)=,EIV,~dt(1)^

    Wheretr——startingtimeofswitchingregime f2——nishtimeoftmnsientgwitchi"gregime 107

4l卷第8

    20078

    电力电子技术

    PowerElectronics

    Vo1.41.No.8

    August,2007

    

    ?一5;5l5

    ,LlS

    毕业._1I56

    耪鬻l:::

    Fig.3TuFll-ontestandtimofftest

    Unfortunately,themeasuredsignalslifeaffectedbyinlmtoffsetanti

    asimpleequationas(1)canbeusedonlyiftheoffsetvaluesare.

    subtractfrommeasuredvalues.Tnfindtheoffsetvaluesofcurrentand voltagesignalsisadifficultproblem.Hereamethoddescribedin10is

    used.ThemethodisusedonHP54l0Aoscilloscopetofindtopandbase vl~ue8asthemostprevalentpointaboveandbelowthewaveform midpoint.Thecollector-emittervoltageis:

    V='--V..=(2)

    Where.''——PolkPt0remittermeasm~dvehage

    ——v0ltanff~tvalue{IhPbasevalueof

    

    theonstatecollector-emittervoltagefromdatasheetor fromstatictest

    Thecollectorcurrentis:

    

    /,=正一,c=_l^(3)

    WhereR_——0axialshuntresistant?e,岫——fhpbasevalueof'

    dv0lIadropofcoaxialshnntresistance

    ^"measumdcurrentr1Jft[,urrenlvalue

    —一

    theleakagecollectorcurrentassumedzPH)

    Themethodissimpleandthetopandbasevaluesareread directlyfromtheo~illoscope.Themethodeauproducethewmngbase ortopvalueswhenalongtailofvoltagewaveorcurrentwaveis associatedwithdampingoscillationwaves.Inordertoimprovethe accuracyoftheswitchingenergylosscalculation,anadequatetime intervalisnecessarytousein(1).Alargeintervalincreasestheerror producedbyoffset,buterrorsalsooccurfortooshortinterva1.Only afterincludingalltaillosses.isthereacloseagreementbetween simulationandmeasurementresuIts.

    Fig.4DynamictestondiodeVD,

    Energylossfromdiodeturn-off

switchingisalsomeasuredusingthe

    sameset-upbyasarrangedinFig.4.

    Thevoltageanticurrentarerecorded

    inFig.5a,handthepowerandener~"

    lossesarecomputedinasimilarway.

    Theturn-ondiodelossesarelowandthe~foredisregarded. Aprogramtocomputetheswitchingtimeandtheenetg'ylossversus d.c.voltage,loadcurrentandjunctiontemperatureanddifferentgate resistorvalues'isdeveloped.Theprogramresultsarelookuptablesa.qin

    appendix1.Switchingenergy,d.c.voltageandcurrentarecomputedfrom voltageandcurrentwuvefoYnl'srecordedindoublepulsetest17~01,The thednuhlepulsemethodisanon-thermalstressmethod.Theswitching

    energyiscomputedasin(1)usingoffsetcompensationasin(2)and(3). Thed.cvoltageresultsasin(4)whichisquitesimilarto(2). :(4)

    Where._thetopvalueoft_l_

    Thetransitoranddiodeturn~ffcurrentvaluearecomputedas in(5):Lt=l,(5)

    Where^.-~thetopvalueof

    Unfortunately.we/:an'tuseasimilar,simpleequationtocompute theturu~)ncurrentvalues.Theturnoncurrent,t,isequaltotheindue

    torcIlrrellt,lc.Tomeasuredirectlytheinductorcurrent,agalvanicinsu

    latedtrmtsducerisrequired,butthisisintroducingatimedelay.Using thetestsetupshowninFig.2,theinductorcurrentcanbecomputedas in(6):,I=-1+,,?(6)

    Where,——thecoaxialshuntmeasuredcurrent

    "I——theeurreutintransistorVTlanditcan}'econsiderate equalIo0allthetime

    ^——thecurrentinthediodeVDIanditappruacheszero

whenVT1isintheonstate

    Afirstdegreepolynomialfunctionisusedtoapproximatetheon

    statetransistorcurrent,tinaleastsquaresapproximation,asshownin Fig.5c,d.Theswitchingmomentt,isdefinedasthetimeinstantwhere thecollectoremittervoltagepassesthroughthehalfthevalue.The

    turn-oncurrentisequaltoattheswitchingtimeinstanttin(7)the

    calculationof.jsshown:.=+t(7)

    hereqI.nJ——Ihepolynomialcoefficientused1ofitthecurrenttothe

    measured

    >a}/caRlJ.atodetllrn13fltesta}c(1IIdIst 020.406n8l0ll0II820

    /.rl

    I)toadvolta,.,ecompulation

    6

    J

    =

    0

    .

    2

    S3

    2

    I

    :.l

    O

    (dll.adc"Ire

    I

    n

    p

    l

    S

".m.?【ati.l1

    Fig.5DiodeturnofftestandLoadcurrentcomputation

    AfterthedesireddynamicandstaticworkpointsoftheIGBTand

    diodearenteasured,thethreedimensiontablesaregenerated.Agraphical representationotthisisshowninFig.6a,theon-statevoltagedropofthe transistoranddiodeveJ'gllscurrentandjunctiontemperature,inFig.6b, theturn-onenergyversusvolta~,currentandjunctiontemperature,Fig.rc, showtheturn--offenergy,andFig.6dshowthediodeturn-offeuergy.Infig- uf.es6b.6cand6dtheuppersurfaceisforahighjunctiontemperatureof I25?.andIhelowersurfaceforajunctiontemperatureof25~C.Combining theTurnonsimulationresultsusingidealcomponentsandtheshown lookuptables,itispossibletoestimatethepowerlosses.Sincethenumber ofnteasurementpointsislimited,interpolationbetweenpointsisuse(1. 4SimpleModels

    Asanalternativetoadvan(.edsem;(?ondu(?t0rmodels.simulation junctiontemperatureisassumedequaltothecasetemperaturebecauseusingidealswitchesanddiodescanbemadefast.Usingidealswitches,

    Table.1Thy~torlurll-on.Thyritorturn.offandDiodeturn-offenergiesversIlscollectorcurre

    nt

    Thyritorturn-onThyritorturn-off"fDi0deturn-off

    t,/A=25?=125?=25?】25%J=25?:125

    V..=500VV.-=600V=500VV.=600VV.=500V1/.=600VV=50OV=60OVl=500VV..=600VV-=500VV=600V

    50.28n0.36nd0.73n0.83mJ0.60nd0.79n0.62nO0.80mJ10.14mJ0.18mJ0.34nd0.40mJ 80.45mJ0.55nd0.94mJ1.03mJ0.931nJ1.09nLf1.OOmJ1.25nOf0.17nd0.21nd0.44nd0.53n

    lOn56ndO,71nd1.17InJ1.34nd1.08mJ1.27n1.15InJ1.37nl0.20n026nd0.55n0.66InJ 15O.96n1.08I.77mJ1.78n1.36nd1.63n1.43n1.82n10.21n027nd0.62n078InJ l08

    thereisarloseagreement

befwPensimulate(1cuI1nts

    and?lagjfthe

    conduf'ti0nvoItagedmp0f

    theIaldeviceisnon.

    snicant.Anextensi0n()f

    theideal(1evicem0deling

    

    0

    .川未

    0蠡蕾

    搀一譬

SimulationwithhlealSwitchModelsCombinedwithMeasuredL0ssDataProvidesaGoodE

    stimateofPowerh)ss

    on-statevoltagedropisimplementedinnlostso-calledidealdevices. Nunlericalconstraintsofmanyeln'uitsimulatorspreventaswitchwith zeFoorinfiniteimpedancetobeimplemented.Theswitchdevicesused hereincludedfiniteimpedance.TheexampleshowninFig.7aUSeSan idealswitchjnasimplebuckconvertersimulatedinSABER.Infigure7b amodeldeveh)pe(1byNISTI",.isused.

    2

    l

    1

    0

    (

    (aWotlageconlro[ted'ideat'

    silchanddiode

    Fig.7Voltagecontmlled'Ideal

    0flGRTanddiode

    (bl^dYanten1odeIOf

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