Single-stage-power-factor-corrected-converter

ElectricPowerSystemsResearch76(2006)534–540Single-stagepower-factor-correctedconverterforswitchedreluctancemotordriveSang-HunLeea,Feel-soonKangb,∗,Sung-JunParkc,SuEogChod,ManHyungLeeaaDepartmentofMechanicalEngineering,PusanNationalUniversity,San30,Jangjurn-dong,Kumjung-gu,Pusan609-735,RepublicofKoreabDepartmentofControlandInstrumentationEngineering,HanbatNationalUniversity,San16-1,Duckmyung,Yuseong,Daejeon305-719,RepublicofKoreacDepartmentofElectricalEngineering,ChonnamNationalUniversity,300Yongbong-dong,Puk-gu,Gwangju500-757,RepublicofKoreadDepartmentofElectricalEngineering,PusanNationalUniversity,San30,Jangjurn-dong,Kumjung-gu,Pusan609-735,RepublicofKoreaReceived18May2004;receivedinrevisedform17August2005;accepted17August2005Availableonline21November2005AbstractAnewsingle-stagepower-factor-correctedconverterisproposedtoimproveinputpowerfactorforanefficientswitchedreluctance(SR)motordrive.TheproposedconverterusesthewindingofSRmotorasaninputinductorforpower-factor-correction.Converterswitchesplaytwoimportantroles;oneistoimprovetheinputpowerfactorandtheotheristoexcitethemotorphase.Consequently,ac-to-dcpowerconverterandSRmotordriverareincorporatedintoonepowerstage,socalledasingle-stageapproachisrealized;thus,itshowsasimplestructure.Alaboratoryprototypetodriveasingle-phase6/6-poleSRmotorismanufacturedtoevaluatetheperformanceoftheproposeddrivesystem.Designexampleisgivenindetail,andthevalidityoftheproposedconverterisverifiedbyexperimentalresults.©2005PublishedbyElsevierB.V.Keywords:Converter;Power-factor-correction;Single-stageapproach;SRmotor1.IntroductionTheprincipalcharacteristicsofswitchedreluctancemotor(SRM)aresimplicity,low-costandrobuststructuresuitableforvariable-speedaswellasservo-typeapplications.Withrelativelysimpledriverandcontrolrequirement,theSRMisgainingagreatattentioninthedriveindustry.Generally,theconventionalSRMdriveremploysadioderectifierwithafiltercapacitortosupplydcvoltagesourcefromacutilityline.Althoughthisstruc-tureissimple,itdrawsapulsatingaclinecurrentresultedinlowpowerfactorandhighharmoniclinecurrent.Withtheincreasingdemandforbetterpowerquality,thisapproachisnolongersuit-ableforhighperformanceSRMdrive.Thebestwaytoobtainahighpowerfactoristheuseofapower-factor-correctioncir-cuitwithaSRMdriver.InordertoachievesinusoidalinputcurrentsandtoimprovethelowpowerfactorinSRMdrivesys-tem,severalapproacheshavebeenintroduced[1–11].Amongthem,theapproachinref.[2]consistsofthecascadedpower∗Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](F.-s.Kang).stagesofaboostandabuckeliminatingpulsewidthmodulation(PWM)controlinthemachine-sideconverterwhiledeliveringsinusoidalacinputcurrent.Thisconvertertopologyhashighpowerfactorandimprovedinputcurrentwaveform;however,thisapproachisnotrecommendablechoiceinpracticalandlowcostapplicationsbecauseofthecomplexityandhighcostduetothecascadedpowerstages.ThedescribedSRMdriveremployingahalf-wavezero-currentswitching(ZCS)quasi-resonantboostconverter[3]obtainedbetterperformancesandhigherpowerdensitiesusinghighqualityrectifierwithcapaci-tiveenergystorage.Linecurrentpollutiongeneratedbyelectricdriveswasreducedbyadditionofbothpassiveinputfiltersandactiveinputcurrentshapers;however,itconsistsoftwo-stageapproachresultedintheincreaseofpowerconversionlosses.Inthispaper,asingle-stagepower-factor-correctedSRMcon-verterispresentedtoimproveinputpowerfactor.Themostoutstandingfigureoftheproposeddriverisasimpleconfig-urationcomparedwithconventionalcounterpartsemployingapower-factor-correctioncircuitry.TheswitchesforSRMdrivearemutuallyusedforpower-factor-correctionandphasemagne-tizing.Animprovedpowerfactorwithstablemotordrivecanbeachievedwithonlyoneadditionalactiveswitch.Thevalidityand0378-7796/$–seefrontmatter©2005PublishedbyElsevierB.V.doi:10.1016/j.epsr.2005.08.005S.-H.Leeetal./ElectricPowerSystemsResearch76(2006)534–540535high-performanceoftheproposedSRMdrivesystemisverifiedbyexperimentalresults.2.Proposedpower-factor-correctedSRMdriverFig.1showsconfigurationsoftheclassicconverterandtheproposedpower-factor-corrected(PFC)SRMdriver,respec-tively.Generally,theconventionalconverterillustratedinFig.1(a)employsabulkcapacitorintheendofthedioderecti-fier.Althoughitshowssimpleconfiguration,itdrawsapulsatingaclinecurrentresultedinlowpowerfactorandhighharmoniclinecurrent.Intheviewpointofenergysaving,toimprovethepowerfactorisveryimportantinpracticalapplications.Tosolvetheproblems,power-factor-correctioncircuitryisoftenaddedinfrontoftheconventionalconverter.However,thetwo-stageapproachhasseveraldisadvantagessuchascomplexityofthecircuitcomposition,additionalcontrolloop,costincrease,etc.OneoftheimportantfactorsintheselectionofadriverfortheSRMmaybethecost;thus,asingle-stagepower-factor-correctedconverterisdesirableforapracticalandlowcostSRMdriveindustry.Fig.1(b)showstheproposedsingle-stagepower-factor-correctedconverterforSRMdrive.Themostremarkablecharacteristicoftheproposedconverteristhatthereisnobulkcapacitorintheendofthedioderectifier.Therefore,itcancon-troltheinputcurrentcoveri