文档名：基于阻抗法的光储逆变器交直流建模及耦合分析
摘要：在共母线式光储逆变器中,交直流单元通过直流母线电容连接.传统的逆变器建模方法将母线电容视为无穷大,认为交直流侧运行相互解耦.然而,当直流母线电容较小时,光储逆变器的交直流侧将产生交互影响,引起电流谐振.该文以单个单元稳定运行为前提,推导出直流共母线系统稳定性的合阻抗比(CIR)判据.该判据的数学形式便于利用Bode图对并联系统的谐振源进行分析与定位.首先,对光储逆变器交直流各单元进行阻抗建模,利用合阻抗比判据分析直流侧储能单元相对于光伏单元更易与网侧发生谐振.然后,通过在电流环路加入陷波器改善储能单元的阻抗特性.最后,仿真及实验结果证实了所提合阻抗比稳定性判据的正确性.
Abstract：Insolar-storageinverters,thephotovoltaicunit,theenergystorageunitontheDCside,andtheinverterunitontheACsideareinterconnectedthroughaDCbus.Typically,theDCbusservestoisolatetheoperationofeachmodule.However,asthebuscapacityreduces,theinter-modulecouplingeffectemerges,leadingtooscillationsinthebusvoltageandcurrent.Assessingthestabilityofthemulti-moduleinterconnectedcouplingsystem,identifyingtheresonancesource,andeliminatingoscillationshavebecomemajorconcerns.TheDCbusstabilityissueinsolar-storageinverterscanbeequatedtothestabilityproblemofamulti-moduleparallelmodel.Inpreviousstudies,the"impedanceratio"methodwascommonlyusedtoassessthestabilityofmulti-moduleinteractivesystems.However,theimpedanceratiomethodcanonlyassessthestabilityofinteractionsbetweentwo-portsources.Whendealingwithmulti-moduleinteractions,thesystemisusuallydividedinto"source"and"load"components.Thisapproachshouldbemoreconducivetoidentifyingandattributingresonancecauseswithinspecificunits.Therefore,thispaperproposesacombinedimpedanceratiostabilitycriterionbasedonthestableoperationofsinglemodules.Itdeducesthatthenumberofpolesintherighthalf-planeoftheparallelimpedanceofeachmoduleimpedanceinthesystemdeterminesthestabilityoftheDCparallelsystem.Accordingly,thesystemstabilitycriterionistransformedintothesumoftheimpedanceratiosofeachunit.ThismathematicalformisbeneficialforassessingsystemstabilityusingthetraditionalBodediagramstabilitymethod.Thesourceofsystemresonanceisdeterminedbycomparingthecontributionoftheamplitude-frequencygainofeachunit'simpedanceratioBodediagramtothesystem'scombinedimpedanceratioattheresonancefrequency.Byimpedancemodelingforeachunitofthesolar-storageinverterandanalyzingtheimpedanceratioBodediagram,itisconcludedthattheenergystorageunitanditsrapidchangeoftheimpedancecharacteristicsinhighfrequencycancausesystemresonance.Incontrast,thephotovoltaicunithasanequivalentinputinternalresistancethatsuppressesthechangeinitsimpedancecharacteristics,remainingresistiveandinductiveatalltimes.Subsequently,anotchfilterisincorporatedintotheenergystorageunit'scontrollertoreducetheresonancepeakoftheopen-looptransferfunctioninhighfrequencyandenhancetheoutputimpedancecharacteristics.Finally,thedevelopedmodelisvalidatedthroughsimulationandexperimentation.Thecauseofsystemresonancecanbeaccuratelyanalyzedandidentifiedthroughcomparativeanalysisandapplyingthecombinedimpedanceratiocriterion.Thecontroldelayoftheenergystorageunitindeedcausesthemutualresonanceproblemofthephotovoltaicstorageinverter.Thephotovoltaicunithasanaturalequivalentinternalresistancethatcontributesverylittletotheresonancepeakandisnotresponsibleforthesystemresonance.Simulationandexperimentalresultsdemonstratethecorrectnessofthemodelandtheeffectivenessoftheproposedstrategy.
作者：李达 张涛Author：LiDa ZhangTao
作者单位：三峡大学电气与新能源学院宜昌443000
刊名：电工技术学报 ISTICEIPKU
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(10)
分类号：TM615
关键词：光储系统 交直流耦合 合阻抗比 稳定性
Keywords：Solar-storagesystem DCandgridsidecoupling combinedimpedanceratio stability
机标分类号：TM711TM46U469.72
在线出版日期：2024年5月31日
基金项目：国网浙江省电力有限公司科技资助项目基于阻抗法的光储逆变器交直流建模及耦合分析[
期刊论文] 电工技术学报--2024, 39(10)李达 张涛在共母线式光储逆变器中,交直流单元通过直流母线电容连接.传统的逆变器建模方法将母线电容视为无穷大,认为交直流侧运行相互解耦.然而,当直流母线电容较小时,光储逆变器的交直流侧将产生交互影响,引起电流谐振.该文以单...参考文献和引证文献
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