文档名：基于SHEPWM的三电平三相逆变器中点电位主动平衡控制策略
摘要：在大功率系统中,常采用特定次谐波消除脉宽调制(SHEPWM)以降低系统的开关损耗.针对三电平中点钳位(NPC)型三相逆变器在SHEPWM下的中点电位偏移问题,分析SHEPWM下逆变器输出相电压基波与3次谐波在不同电压相位范围内对中点电位的影响,设计两种在基波周期内对中点电位总充放电效果相反的开关角组合方案,并提出一种通过测量中点电位偏移值及中点电位滞环控制,选择不同的开关角组合方案进行调制的中点电位主动平衡控制策略.实验结果验证了所提出方法的实用性及有效性.
Abstract：Inthehigh-powersystem,thethree-levelneutral-pointclampedinverterneedstoadoptSHEPWMtoreducetheswitchingpowerloss.Thetraditionalneutral-pointpotentialactivebalancecontrolstrategyadjuststhedutycycleofthezero-levelofphasevoltagebysuperimposingaslightanglebasedontheswitchingangleofSHEPWMfromthepolarityofeachphaseloadcurrentandneutral-pointpotentialshift.However,thesmallnumberofSHEPWMswitchingangleslimitstheneutral-pointpotentialbalanceability.ThefewerthenumberofSHEPWMswitchingangles,theweakertheneutral-pointpotentialbalanceability.Therefore,thispaperanalyzestheinfluenceofthefundamentalwaveandthethirdharmonicoftheoutputphasevoltageunderSHEPWMontheneutral-pointpotentialinadifferentrangeofvoltagephaseangles,designstwoswitchinganglecombinationschemeswithoppositeeffectsontheneutral-pointpotentialinthefundamentalwaveperiod,andproposesamethodtocontroltheneutral-pointpotentialbyselectingdifferentswitchinganglecombinationschemetomodulateaccordingtotheoffsetvalueandthehysteresisoftheneutral-pointpotential.Theinfluenceanalysisofthefundamentalwaveandthethirdharmonicwaveontheneutral-pointcurrentshowsthattheneutral-pointcurrentcomponentsgeneratedbythefundamentalwaveandthethirdharmonicwavehavetriplefrequencyfluctuation.Moreover,whentheamplitudeofthethirdharmonicis0.2636timesthatofthefundamentalwave,theintegraloftheneutral-pointcurrentcomponentsgeneratedbythefundamentalwaveandthethirdharmoniccancelseachotherintheintervalofthefundamentalwavephaseangleevery60degrees.Theneutral-pointcurrentintegralinthewholefundamentalwavecyclecanbeadjustedbysettingthethirdharmoniccontentatevery60degreesofthefundamentalwavephaseangletocontroltheneutral-pointpotential.Therefore,twoswitchinganglecombinationschemesareproposed,withoppositeeffectsontheneutral-pointpotentialandnoeffectonthefundamentalvoltage.However,thetwoswitchinganglecombinationschemesmayincreasethenumberofswitchingtimesofthesystembecauseitissometimesnecessarytoaddextraswitchinganglestoensurethecorrectswitchingoftheswitchingangleswithdifferentthirdharmoniccontent.Theanalysisoftheswitchanglecombinationschemeswiththedifferentnumbersofswitchanglesshowsthattheproposedschemescanonlyincreasefourswitchingactionsinthewholefundamentalwavecycleatmost,andwillnotaffectthelowswitchingfrequencycharacteristicsofSHEPWM.However,theneutral-pointvoltagehysteresiscontrolisneededtodeterminetheswitchingangleusedtomodulate.Whentheneutral-pointvoltagedeviationiswithintheacceptablerangeofthesystem,theSHEPWMswitchinganglewithoutmodificationisusedtoensuretheswitchingpowerlossandtheharmonicperformanceofthesystem.Theexperimentalresultsshowthatcomparedwiththetraditionalneutral-pointpotentialactivebalancingmethodbasedonSHEPWM,theproposedmethodhasabetterdynamicbalancingeffectunderdifferentworkingconditions.
作者：董志强 王琛琛 周明磊 刘明月 李凯Author：DongZhiqiang WangChenchen ZhouMinglei LiuMingyue LiKai
作者单位：北京交通大学电气工程学院北京100044
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(4)
分类号：TM464
关键词：三电平中点钳位型逆变器 中点电位控制 特定谐波消除脉宽调制 3次谐波
Keywords：Three-levelneutral-pointclampedinverter neutral-pointpotentialcontrol harmoniceliminationpulsewidthmodulation(SHEPWM) third-harmonic
机标分类号：TM464TU4TM921
在线出版日期：2024年3月5日
基金项目：北京市自然科学基金资助项目基于SHEPWM的三电平三相逆变器中点电位主动平衡控制策略[
期刊论文] 电工技术学报--2024, 39(4)董志强 王琛琛 周明磊 刘明月 李凯在大功率系统中,常采用特定次谐波消除脉宽调制(SHEPWM)以降低系统的开关损耗.针对三电平中点钳位(NPC)型三相逆变器在SHEPWM下的中点电位偏移问题,分析SHEPWM下逆变器输出相电压基波与3次谐波在不同电压相位范围内对...参考文献和引证文献
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