基于背靠背VSC的微电网并网研究的中期报告

基于背靠背VSC的微电网并网研究的中期报告Abstract:Microgridsarebecomingincreasinglypopularduetotheirabilitytosupplypowerindependentlyofutilitygrids,thusincreasingreliabilityofpowersupply.Thisreportpresentstheprogressmadetowardsdevelopingaback-to-backvoltagesourceconverter(VSC)-basedmicrogridsystem.ThemicrogridsystemconsistsofaDCbuswithtwomicrogridsystemsconnectedback-to-back,eachequippedwithaVSC.Thesystemoperatesinislandedmode,andcanbeconnectedtotheutilitygridwhennecessary.Thereportprovidesanoverviewofthemicrogridsystem,includingitstopology,controlstrategies,andsimulationresults.Simulationresultsdemonstratethatthesystemcansuccessfullytransitionbetweenislandedandgrid-connectedmodes,andthatvoltageandfrequencyarekeptwithinspecifiedlimits.Introduction:Microgridsaresmall-scalepowersystemsthatcanoperateindependentlyorbeconnectedtotheutilitygrid.Microgridstypicallyconsistofdistributedenergyresources,includingwindturbines,solarpanels,fuelcells,andenergystoragesystems.TheseresourcesareconnectedtoaDCbus,whichisthenconnectedtoanACbusthroughavoltagesourceconverter(VSC).TheVSCallowsthemicrogridtotransitionfromgrid-connectedtoislandedmode,andviceversa.Microgridsareincreasinglypopularduetotheirabilitytosupplypowerindependentlyofutilitygrids,thusincreasingthereliabilityofpowersupply.Thisreportpresentstheprogressmadetowardsdevelopingaback-to-backVSC-basedmicrogridsystem.Themicrogridsystemconsistsoftwomicrogridsystemsconnectedback-to-back,eachequippedwithaVSC.Thesystemoperatesinislandedmode,andcanbeconnectedtotheutilitygridwhennecessary.Thereportprovidesanoverviewofthemicrogridsystem,includingitstopology,controlstrategies,andsimulationresults.Topology:ThetopologyofthemicrogridsystemisshowninFigure1.Themicrogridsystemconsistsoftwomicrogridsystemsconnectedback-to-back,eachequippedwithaVSC.TheVSCallowsthesystemtotransitionbetweenislandedandgrid-connectedmodes.Themicrogridsystemsarecomposedofdifferentenergysources,suchasphotovoltaicpanels(PV),windturbines,fuelcells,andbatteriesthatcanprovidecontinuouspowerorserveasbackuppowerduringoutages.Theenergystoragesystemscanbalancethepowergeneratedbythegridandstoreexcesspowerduringlowdemandperiodsthatcanthenbeusedduringpeakdemandperiods.Themicrogridsystemalsocontainsaprotectionsystemconsistingofcircuitbreakers,whichwilldisconnectthemicrogridfromthegridincaseofafaultorotherabnormalconditions,ensuringthesafetyofboththemicrogridandthegrid.ControlStrategy:ThecontrolstrategyforthemicrogridsystemisshowninFigure2.Thecontrollerisresponsibleforensuringthatthevoltageandfrequencyremainwithinspecifiedlimitswhenoperatinginislandedmode.Whenthesystemisconnectedtotheutilitygrid,thecontrollerwillalsoregulatethepowerflowbetweenthemicrogridandthegrid.Thecontrollerconsistsoftwomaincomponents:thevoltagecontrollerandthefrequencycontroller.Thevoltagecontrollerisresponsibleforregulatingthevoltageatthemicrogridduringislandedmode.ThevoltagecontrollerwilladjusttheDCvoltageleveltomaintainaconstantACvoltageoutput.Thefrequencycontrollerisresponsibleforregulatingthefrequencyatthemicrogrid.ThefrequencycontrollerwilladjusttheoutputfrequencybycontrollingtheactivepowerorreactivepoweroftheVSC.Thiswillensurethatthefrequencyofthemicrogridremainswithinspecifiedlimits.SimulationResults:Simulationresultsshowthatthemicrogridsystemcansuccessfullytransitionbetweenislandedandgrid-connectedmodes.Thesystemcanmaintainastablevoltageandfrequencyoutputduringbothmodesofoperation.Duringislandedmode,thesystemcansuccessfullyregulatethevoltageandfrequencyoutputwithinspecifiedlimits.Conclusion:Thisreportpresentsprogressmadetowardsdevelopingaback-to-backVSC-basedmicrogridsystem.Thesystemconsistsoftwomicrogridsystemsconnectedback-to-back,eachequippedwithaVSC.Thesystemoperatesinislandedmode,andcanbeconnectedtotheutilitygridwhennecessary.Thereportprovidesanoverviewofthemicrogridsystem,includingitsto