资源描述:
《The Modeling and Control of a Cascaded-Multilevel Converter-Based STATCOM(Dissertation_phd) 英文文献资料》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、TheModelingandControlofaCascaded-MultilevelConverter-BasedSTATCOMSirirojSirisukprasertDissertationsubmittedtothefacultyoftheVirginiaPolytechnicInstituteandStateUniversityinpartialfulfillmentoftherequirementsforthedegreeofDoctorofPhilosophyinElectricalEn
2、gineeringJasonLai,Co-ChairmanAlexQ.Huang,Co-ChairmanJacobusDanielvanWykYiluLiuMartinKlausFebruary13,2004Blacksburg,VirginiaTheUnitedStateofAmericaKeywords:Cascadedmultilevelconverters,multilevelvoltagesourceconverters,STATCOM©Copyright2004,SirirojSirisu
3、kprasertTheModelingandControlofaCascaded-MultilevelConverter-BasedSTATCOMSirirojSirisukprasert(ABSTRACT)Thisdissertationisdedicatedtoacomprehensivestudyofstaticsynchronouscompensator(STATCOM)systemsutilizingcascaded-multilevelconverters(CMCs).Amongflexi
4、bleACtransmissionsystem(FACTS)controllers,theSTATCOMhasshownfeasibilityintermsofcost-effectivenessinawiderangeofproblem-solvingabilitiesfromtransmissiontodistributionlevels.Referringtotheliteraturereviews,theCMCwithseparatedDCcapacitorsisclearlythemostf
5、easibletopologyforuseasapowerconverterintheSTATCOMapplications.ThecontrolsfortheCMC-basedSTATCOMwere,however,verycomplicated.Theintricatecontroldesignwasbegunwithoutwell-definedsystemtransferfunctions.Thecontrolcompensatorswere,therefore,randomlyselecte
6、d.Thestabilityofthesystemwasachievedbytrialanderrorprocesses,whichweretime-consumingandineffective.Tobeabletooperateinahigh-voltageapplication,alargenumberofDCcapacitorsareutilizedinaCMC-basedSTATCOM.AllDCcapacitorvoltagesmustbebalancedinordertoavoidove
7、r-voltagesonanyparticularlink.NotonlydotheseunevenDCvoltagesintroducevoltagestressonthesemiconductorswitches,buttheyalsolowerthequalityofthesynthesizedoutputwaveformsoftheconverter.PreviousresearchesintoDCcapacitorvoltage-balancingtechniqueswereverystra
8、ightforward,inthatindividualvoltagecompensatorswereaddedintothemaincontrolloop.However,thecompensatordesignfortheseindividualloopsisveryproblematicbecauseofthecomplexityofthevoltage-looptransferfunctions.Basically,thetrialanderro