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《igbt驅(qū)動(dòng)保護(hù)電路的設(shè)計(jì)與測(cè)試(design and test of igbt driver and protection circuit)》由會(huì)員上傳分享,免費(fèi)在線閱讀,更多相關(guān)內(nèi)容在教育資源-天天文庫。
1、igbt驅(qū)動(dòng)保護(hù)電路的設(shè)計(jì)與測(cè)試(DesignandtestofIGBTDriverandprotectioncircuit)1IntroductionIGBTsetpowerMOSFETandbipolarpowertransistorsinoneoftheadvantages,withvoltagecontrol,highinputimpedance,smalldrivingpower,simplecontrolcircuit,lowswitchingloss,switchingspeedandlowonstatevoltage,highvoltageandhig
2、hcurrentcharacteristicssuchaseasy.IntheapplicationofIGBT,driveandprotectionhavealwaysbeenthekeytechnologyofresearch,especiallyovercurrentprotection.ThecharacteristicsoftheIGBTdeviceitselfanditsoperatingconditionsinthecircuitdetermineitsover-currentprotectioncomparedwithotherswitchingdev
3、icesareverydifferent.Theover-currentprotectioncircuitofIGBTisdirectlyrelatedtotheworkingperformanceandoperationsafetyofthewholesystem.2IGBTdrivecircuitSwitchingcharacteristicsof2.1IGBTAsshowninFig.1,theequivalentcircuitofIGBTandtheinternalstructureofthedeviceshowthattheswitchingcontrolo
4、fIGBTisaccomplishedbyagatestructuresimilartothatofMOSFET,sotheswitchingprocessofIGBTandMOSFETisapproximatelysimilar.Fig.2isthewavetypeofVGE,ICEandVCEforIGBThardswitching.Whenopened,whenVGEreachedthethresholdaftertheopening,totheT2time,themaximumvalueofICE,VCEdown,becauseMillercapacitanc
5、eCGCandMOSFETthesameeffect,thegatevoltageisalmostconstantanddelayedtheopeningprocessofIGBT,whenVCEfellover,ICEreachedsteadyvalue,CGCforVGEtodisappear.Thefastrisingratereachedthemaximum.Inordertoreducethiseffect,theinternalresistanceofthegatedrivesourceshouldbesmallenoughtoincreasethecur
6、rentflowingthroughtheCGCandspeeduptheopening.Similarly,duetotheeffectofMillercapacitance,whentheVCErises,theVGEhasanapproximatelyconstanttime,whichaffectstheprocessofturnoff.Inaddition,becausetheIGBTisabipolardevice,intheturnoffprocessofarecombinationprocess,causingthetailcurrentisturne
7、doff,thisisthebiggestdifferenceofIGBTandMOSFETswitch,asshowninFigure2,whichisthemostimportantfactorinfluencingtheworkingfrequencyofIGBT.Requirementsof2.2IGBTdrivecircuit2.2.1turnonpositivegridvoltageTheIGBTstaticcharacteristiccurveshowsthatthelargerthepositivegatevoltageVGEis,t