配电网DSTATCOM及其控制策略的研究

分类号：密级：UDC：编号：河北工业大学硕士学位论文配电网DSTATCOM及其控制策略的研究论文作者：张少晨学生类别：全日制学科门类：工学学科专业：电气工程指导教师：张福民职称：副教授DissertationSubmittedtoHebeiUniversityofTechnologyforTheMasterDegreeofElectricalEngineeringResearchonDSTATCOMinDistributionNetworkanditsControlStrategybyZhangShaochenSupervisor:Prof.ZhangFuminDecember2013I摘要如今，现代科学技术发展进入了一个新阶段，在配电网中并入了许多的非线性、冲击性的用电设备，导致配电网电压不平衡。若对DSTATCOM装置仅采用平衡情况下的控制方法，配电网的三相不平衡会给补偿装置造成不利影响。本文以级联多电平DSTATCOM为研究对象，重点研究在配电网电压不平衡环境下DSTATCOM补偿装置应采取的控制策略，并仿真验证所提方法的正确性。首先对本文选用的级联多电平DSTATCOM电路结构做了详细的说明，并分析了无功补偿装置的工作原理和数学模型，为后文进一步分析控制策略奠定了基础。之后对无功电流检测方法进行理论分析，并对两种载波相移PWM的调制方法做了详细地对比分析，在平衡条件下数学模型的基础之上，研究了级联多电平DSTATCOM装置在配电网平衡条件下的控制策略。然后，本文介绍了配电网电压不平衡产生原因及危害，同时介绍了应用于配电网不平衡分析中的研究方法和相序分离技术。在此基础之上，建立了配电网电压不平衡时补偿装置的负序数学模型。本文采用了改进型锁相环技术，保证了补偿装置能够准确跟踪基波正序分量的相角，并进行了仿真验证。为了解决配电网电压不平衡现象，本文采用了一种基于双序电流环的控制策略。该策略对负载电流进行相序分离，运用状态解耦控制，实现了对配电网中无功分量和负序分量的分别补偿，保证配电网电压与电流相位相同，提高配电网的功率因数。为了抑制配电网可能出现的电压跌落现象，本文采取了电压跌落控制策略，通过控制DSTATCOM装置向配电网注入无功功率的方式，实现对电压跌落的补偿。并在MATLAB/Simulink环境下进行仿真验证所提策略的正确性。关键字：级联多电平，配电网静止同步补偿器，载波移相PWM控制，三相不平衡IIABSTRACTToday,modernscienceandtechnologydevelopmenthasenteredanewstage，alotofnonlinear,impactofpowerequipmentputintothedistributionnetwork，whichleadtodistributionnetworkvoltageunbalance.Theunbalanceofthedistributionnetworkwillcausealotofharmfuleffectsoncompensationdevice,ifitonlyusestheoperationofthebalancecasecontrolmethodtoDSTATCOM.ThisthesisfocusesonresearchingundertheenvironmentofdistributionnetworkvoltageunbalanceofDSTATCOMdeviceshouldbetakentocontrolstrategyisbasedonthecascademultilevelDSTATCOMastheresearchobject.Simulationresultsshowtheaccuracyandeffectivenessofthecontrolstrategyproposedinthisthesis.Firstofall,thispaperexplainsthechooseofthecascademultilevelDSTATCOMcircuitstructureindetail,andanalyzestheworkprincipleandmathematicalmodelofreactivepowercompensationdevices,whichlaidafoundationforfurtheranalysiscontrolstrategy.Aftertheoryanalysisthispapercarriesoutonthereactivecurrentdetectionmethod,andthetwokindsofcarrierphasesshiftPWMmodulationmethodmadeadetailedcomparisonandanalysis,undertheconditionofequilibriummathematicalmodel,cascadingmultilevelDSTATCOMdevicearestudiedundertheconditionofthepowerbalancecontrolstrategy.Secondly,thereasonandaffectofdistributionnetworkvoltageimbalanceisexplainedbythepaper.Italsointroducestheresearchintheappliedtotheunbalanceddistributionnetworkanalysismethodandthephasesequenceseparationtechnologyinthesametime.Baseontheanalysisabove,thedistributionnetworkvoltageunbalancecompensationdevicemathematicalmodelofnegativesequenceisestablished.Thethesisadoptedthemodifiedphaselockedlooptechniquetoensurethecompensationdevicecanaccuratelytrackthefundamentalpositivesequencecomponentofthephaseangle,anddothesimulationofverification.Inordertosolvethedistributionnetworkvoltageimbalance,dualsequencecurrentloopcontrolstrategyisadoptedinthispaper.ThepositiveandnegativesequencecomponentsdetectedbythisstrategywhichusedaPIregulatoranddecouplingcontrolmethod.Thereactivepowerandnegativesequencecomponentscanbeeffectivelycompensatedandthepowerfactorofdistributionnetworkhastobeimproved.Inordertosolvethedistributionnetworkvoltagesag,thispapertakeavoltagesagcontrolmethod.ThisstrategyachievethevoltagesagcompensationbycontrollingtheDSTATCOMdevicetoinjectreactivepowerdistributiongrid.AndundertheenvironmentofMATLAB/Simulinksimulationresultsverifytheaccuracyoftheproposedmethod.KEYWORDS:Cascadedmulti-level,DSTATCOM,CPS-SPWM，three-phaseunbalanceIII目录第一章绪论........................................................................................................................-1-1.1研究背景及意义............................................................................................................-1-1.2柔性交流输电技术........................................................................................................-3-1.3DSTATCOM的研究现状..............................................................................................-3-1.4课题研究的主要内容....................................................................................................-4-第二章DSTATCOM基本原理及CPS-PWM技术...................................................................-6-2.1基本电路结构................................................................................................................-6-2.1.1多电平技术.........................................................................................................-6-2.1.2主电路结构.........................................................................................................-7-2.2工作原理及模型............................................................................................................-8-2.2.1无功补偿工作原理.............................................................................................-8-2.2.2DSTATCOM数学模型...................................................................................-10-2.3无功电流检测方法......................................................................................................-12-2.3.1p-q检测方法....................................................................