基于箝位双子模块的MMC-HVDC起动控制策略.pdf

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1、第41卷第11期电力系统保护与控制vo1．41NO．112013年6月1日PowerSystemProtectionandControlJun．1，2013基于箝位双子模块的MMC-HVDC起动控制策略薛英林，徐政(浙江大学电气工程学院，浙江杭州310027)摘要：分析了基于箝位双子模块的MMC-HVDC正常自励起动过程，将起动过程分为两个基本阶段，即不控充电阶段和可控充电阶段。利用电路原理方法化简了不控充电阶段的系统等值电路，推导了最大充电电流与限流电阻之间的关系，并指出在该阶段由于二极管箝位作

2、用电容无法充电至额定状态。设计了三种可控充电方法以对电容继续充电获取足够的能量，其中方法一利用直流电压控制器和调制均衡策略，而方法二和方法三则通过改变充电回路中等效内电势和等效电容实现电容完全充电。为充分发挥系统故障穿越能力，设计了直流侧暂时性和永久性故障后的系统自动再起动控制时序。在PSCAD／EMTDC中搭建两端有源的MMC-HVDC系统，仿真结果表明所提出的起动控制策略效果良好关键词：模块化多电平换流器；箝位双子模块；限流电阻；电容充电；正常自励起动；自动再起动Startcontrolfor

3、theMMC．HVDCsystembasedonclampdoublesubmoduleXUEYing—lin，XUZheng(CollegeofElectricEngineering，ZhejiangUniversity,Hangzhou310027，China)Abstract：Theself-startprocedureofthemodularmultilevelconvener(MMC)basedHVDCsystemwhichadoptsclampdoublesubmodules(CDSM

4、)isanalyzed．Thisprocedureisdividedintotwobasicstages，i．e．，uncontrolledchargingstageandcontrolledchargingstage．Theequivalentcircuitinuncontrolledstageissimplifiedaccordingtotheoremofelectricalcircuitandtherelationshipbetweenthemaximumchargingcurrentand

5、curent-limitresistorisderived．Furthermore，itisindicatedthatallcapacitorscouldnotbefullychargedtotheratedvalue，owingtoclampingfunctionalityofdiodes．Inordertocontinuouslychargethesecapacitors，threecontrolledchargingmethodsareproposed，enablingthateachach

6、ievesenoughstoredenergy．Amongthem，methodNo．1takesadvantageoftheDCvoltagecontroller,whichusesthemodulationandbalancingstrategy；methodNo．2andmethodNo．3arerealizedbychangingthechargingloop’Sequivalentelectricpotentialandequivalentcapacitance．Infullyimple

7、mentingthefaultsride-throughability,auto—restartcontrolsequencesundertemporaryandpermanentDCfaultsaredesigned．Finally,adigitalmodeloftheMMC—HVDCsystemwithtwoactiveterminalsisrealizedinthePSCAD／EMTDCsoftware．Thesimulationresultsshowthattheproposedcontr

8、olstrategieshavesatisfactoryperformance．ThisworkissupposedbytheNationalHighTechnologyResearchandDevelopmentProgramofChina(863Program)(No．2012AA050205)．Keywords：modularmultilevelconvener；clampdoublesubmodule；current-limitingresistor；capacitorch