A10KVshunthybridactivefilterforapowerdistributions

Abstract—thispaperanalyzesthecompensationperformanceofashunthybridactivepowerfilter.Thehybridactivepowerfilter,whichcombinespassivefilterandactivepowerfilter,hasbothrespectivemerits,andisanimportantdevelopingtrendoffilteringdevice.Thehybridactivepowerfiltercanreducethecapacityofactivepowerfiltereffectivelyandismoresuitablefortheengineeringapplicationforhighvoltagenonlinearloads.Thecompensationperformanceofhybridactivepowerfilterisanalyzedbyestimatingtheeffectofdifferentactivepowerfiltergainandparameterschange.Then,aconclusionhasbeenobtainedthattheharmonicattenuationrateisinsensitivetothevariationofpassiveparameterswhentheactivepowerfilterwithanenoughfeedbackgainiscombined.Finally,thefeasibilityandvalidityofproposedschemeisverifiedbySimulationusingMatlabandahybridshuntactivepowerfilterprototype.IndexTerms--Currentharmonicscompensation,activepowerfilter,passivefilter,generalizedintegrators.I.INTRODUCTIONnrecentyears,thedevelopmentofpowerelectronicsbringsconveniencetoenergyconversionandutilizationandalsocausespowerqualityproblems.Asoneofthekeytechnologiesincombatingpowergridpollutionandimprovingthepowerquality,activepowerfilter(APF)hasbecomeanewresearchemphasisinpowerelectronicstechnology[1]-[5].Becauseofhighinitialcost,thefurtherapplicationofactivepowerfilterisrestricted.TheHAPF(HybridActivePowerFilter),combinationofAPFandpassivefilter(PF),canreducethecapacityofAPFeffectivelyandismoresuitablefortheengineeringapplicationofAPFforhighvoltagenonlinearloads.Traditionally,Passivefilterhasbeenusedtoeliminatetheharmonicinpowersystemduetohislowcostandhighefficiency.Apassivefiltershowsthelowimpedanceattunedfrequencytoabsorbcurrentharmonicandhasagoodcompensationperformance.However,passivefilterhasthedisadvantageofdependingontheparametersofpowersystem,susceptibletotheloadandpowersystemresonantandthecharacteristicchangeduetoaging.Inaddition,passivefilterusuallyisdesignedwithfixedparameters,whichcannotbelightlyadaptedforthevariationaloperationcondition.Activepowerfilterhasbeendevelopedtoovercomeofdisadvantagesofpassivefilterandcanprovideflexibleandreliablecompensation,butisnotacost-effectivesolutionduetothehighoperationcost.Becauseofthedrawbacksofpassivefilterandactivepowerfilter,theresearchonhybridactivepowerfilterhasbecomemoreattractive[6]-[9].Hybridactivepowerfiltercomposedofpassivefilterconnectedinseriestoanactivepowerfilterimprovesthecompensationperformanceofpassivefilterremarkably,givemoreflexibilityandreliabilitytofilterdevice,andredoundtotheuseofactivepowerfilterinhigh-powersystemavoidingtheexpensiveinitialcost.Inthispaper,thecompensationperformanceofhybridactivepowerfilterinanindustrialpowerdistributionsystemisanalyzedbyestimatingtheeffectofdifferentactivepowerfiltergainandparameterschange.Finally,thecompensationofhybridactivepowerfilterisverifiedbysimulationandalaboratoryprototype.Thepassivefilterofprototypewastunedattheseventhharmonicandthegeneralizedintegratorsareusedtoeliminatethe5th,11thand13thharmoniccurrent[10].II.PRINCIPLESOFCURRENTHARMONICCOMPENSATIONThehybridactivepowerfiltertopologyisshowninFig.1,whichconsistsofathree-phasepulsewidthmodulation(PWM)voltage-sourceinverter(activepowerfilter,APF)andthepassivefilterconnectedinseriestoAPFthroughcouplingtransformer.Generally,theactivepowerfilteractsasacontrolledvoltagesourceandforcetheharmoniccurrentintothehybridactivepowerfilter.Theprincipleofoperationofcurrentharmonicisexplainedbythesingle-phaseequivalentcircuitshowninFig.2whenthefeedbackcontrolisappliedtotheactivepowerfilter.Inthecurrentharmoniccompensationstrategy,theactivepowerfilterisconsideredasacontrolledvoltagesourceVAPF,andZFistheimpedanceofpassivefilter,ILhistheloadharmoniccurrent,ZSisthesystemimpedance.Inordertoeliminateharmonicofthesystemcurrent,theactivepowerfilteriscontrolledasacurrentcontrolledvoltagesource.TheactivepowerfilterimposesavoltagesignalVAPFthatforcesloadharmoniccurrentflowintothepassivefilter,thusimprovingitscompensationperformanceindespiteofthevariationinthetunedfrequencyofthepassivefilter.ThevoltagereferenceofactivepowerfilterisequaltoshAPFIKV⋅=*(1)Where,Kistheharmoniccompensationgain.Supposingutilityvoltageispuresinusoidal,therationbetweentheutilityharmoniccurrentandtheloadharmoniccurrentisobtained,whichcanbeusedtodenotethefilteringcharacteristicsofhybridactivepowerfilter.KZZZIIFSFLhsh++=(2)TheFig.2(b)isequivalentforIshtoFig.2(a)byequation(2),whichmeansthatapureresistorKisconnectedinserieswithZSasshowninFig.2(b)toblocktheuncompensatedA10KVShuntHybridActiveFilterforaPowerDistributionSystemWuJian,HeNa,XuDianguoDepartmentofElectricalEngineering,HarbinInstituteofTechnology,Harbin,150001,CHINAE-mail:[e-mail]978-1-4244-1874-9/08/$25.00©2008IEEE927Authorizedlicenseduselimitedto:CHINAUNIVERSITYOFMININGANDTECHNOLOGY.DownloadedonDecember8,2009at20:11fromIEEEXplore.Restrictionsapply.loadharmoniccurrentflowingintotheutility.Equation(2)depictthatifFZK≥,Kwilldominatethefiltercharacteristicsandtheharmoniccurrentwillbeforcedintothepassivefilter.Otherwise,Kactsasaresistancetodampresonan