单相SPWM逆变器并联解耦控制策略

华北科技学院毕业设计外文资料翻译1英文资料原文来源:出自JOURNALOFELECTRONICSCIENCEANDTECHNOLOGYOFCHINA,VOL.7,NO.3,SEPTEMBER2009DecouplingControlStrategyforSinglePhaseSPWMParallelInvertersShun-GangXu,Jian-PingXu,andTai-QiangCaoAbstract:AdecouplingcontrolstrategyofinverterparallelsystemisproposedbasedontheequivalentoutputimpedanceofsinglephasevoltagesourceSPWM(sinusoidalpulsewidthmodulation)inverter.Theactivepowerandreactivepowerarecalculatedintermsofoutputvoltageandcurrentoftheinverter,andsenttotheotherinvertersintheparallelsystemviacontrollerareanetwork(CAN)bus.Bycalculatinganddecouplingthecircumfluenceoftheactivepowerandreactivepower,theinverterscanshareloadcurrentviatheregulationofthereference-signalphaseandamplitude.Experimentalresultsofan110V/2kVAinverterparallelsystemshowthefeasibilityofthedecouplingcontrolstrategy.IndexTerms-CANbus,currentsharing,inverters,paralleloperation.1.IntroductionParalleloperationofinvertersisanefficientwaytoenhancethecapacityandreliabilityofinvertersystems.Thekeyissueofparalleloperationisthedistributionoftheloadcurrent.Inaninverterparallelsystem,theamplitudesandphasesofoutputvoltagesofallinvertersshouldstrictlyequaltoeachothertoguaranteethateachinvertersharesthesameloadcurrent.Otherwise,thecurrentcircumfluenceandoverloadofsomeinvertersintheinverterparallelsystemmayexist.Thecurrentcircumfluencemayalsodecreasetheefficiencyandreliabilityoftheinverterparallelsystem.Therearevarioustechniquesforthecontrolofinverterparalleloperation.Amongthesetechniques,centralcontrolandmaster-slavecontrolareeasytoimplementandhavegoodcurrent-sharingperformance.However,thesetwocontrolstrategiesworkatthecostof华北科技学院毕业设计外文资料翻译2systemreliabilitybecauseofconjunctionoperationamonginverters.Ininstantaneous-currentcontrolofinverterparallelsystem,thereisacurrentbustosharethecurrentsignalamonginvertersandtheinstantaneouscircumfluenceisusedtoregulatetheoutputcurrent,eachinverterhasgoodtransientperformanceandtheparallelsystemhasgoodcurrentsharingperformance.However,itsanalogsignalcommunicationiseasytobedisturbedandthesignalisolationiscomplicated,whichdecreasethereliabilityoftheparallelsystem.Independentcontrolwithoutinterconnectiondroopstheoutputvoltageandfrequencyofinverters,thelinkamonginvertersisonlyviapowerlines.Thusfewerinterconnectionsareneededandthereliabilityofinverterparallelsystemsisimproved.Traditionally,thiscontrolstrategyassumestheoutputimpedanceofinvertersismainlyinductiveduetohighinductivecomponentofthelineimpedanceandthelargeinductorfilter.Thusactivepower-frequencydroopandreactivepower-voltagedroopschemesareadopted.However,thisisnotalwaystrueastheclosed-loopoutputimpedancealsodependsonthecontrolstrategy,andthelineimpedanceispredominantlyresistiveforlowvoltagecabling.Thus,thereiscouplingrelationshipbetweenoutputactive/reactivepowerandfrequency/amplitudeoftheoutputvoltage.Traditionalindependencecontrolmayleadtoinstabilityofinverterparallelsystems.Inthispaper,adecouplingcontrolstrategyforinverterparallelsystemsisproposed.Theactivepowerandreactivepowerofinvertersinaparallelsystemarecalculatebytheircorrespondingoutputvoltageandoutputcurrent,andtheoutputpowerinformationissharedbycontrollerareanetwork(CAN)buscommunication.Thentheactiveandreactivepowercircumfluenceofeachinverteriscalculatedandappliedtoregulateitscorrespondingoutputvoltageandoutputfrequencybydecouplingofthepowercircumfluence,respectively.Thus,theproposeddecouplingcontrolstrategyovercomesthedisadvantagesofinverterparallelsystemscontrolledbyindependencecontrolwithoutintercommunicationandinstantaneous-currentcontrol.Theinverterparallelsystemimplementedbythisstrategycanachievebettercurrent-sharingperformance,goodstability,andgoodreliability.华北科技学院毕业设计外文资料翻译32.AnalysisofSinglePhasePWMInverterDualclosed-loopfeedbackcontrolisusuallyadoptedtocontrolsinglephaseinverters.Fig.1showsadualclosed-loopfeedbackcontrolschemewithaninductor-currentinnerloopandacapacitorvoltageouterloop.Thecapacitor-voltageouterloopadoptsproportion-integralcontroltoregulateoutputvoltage,wherePvkandIvkareproportionalcoefficientandintegralcoefficient,respectively.Theinductor-currentinnerloopusesproportionalcontroltoenhancethetransientresponseoftheinverter,Pikisaproportionalcoefficient.InFig.1,thepowerstageincludesafull-bridgeconfigurationandanL-Cfilter,inVisDClinkvoltage,1sto4sarepowerswitches,LandCarefilterinductorandcapacitor,refvisasinusoidalreferencevoltagesignaloftheinverter,Lristhesumofinductorequivalentseriesresistance,switchon-resistance,andconnection-lineresistance.Accordingtononlinearcontrolandfeedbacklinearizationtheory,open-loopaveragedoutputvoltagecanbecharacterizedby2000002LLindvdvdiLCrCvLriVudtdtdt(1)wherexmeanstheaveragevalueofxoveroneswitchingcycleanduisthecontrolvariable,whichcantakethevalues1,0,or-1,dependingonthestateofswitches1S,2S,3Sand4S.Forthedualclosed-loopfeedbackcontrolinvertershowninFig.1,thecontrollercanbecharacterizedby000PvIvinrefPikskVuvviCsvks(2)From(1)and(2),thedynamiccharacteristicsoftheclosed-loopoutputvoltagecanbeexpressedinL