动态电压恢复器的MATLAB仿真---毕业设计

-Ⅰ-摘要由于现代科技的发展，非线性负载和电力电子装置应用广泛，它们对电压扰动极其敏感，几个周波的电压扰动可能导致它们失灵或彻底损坏。在各种电压扰动或干扰因素中，电压跌落尤为明显，并已成为影响诸多用电设备正常运行的非常严重的动态电能质量问题。而且电压跌落具有不可预见性，影响范围较大，会造成相当大的经济损失。因此，利用补偿装置消除瞬时电压跌落、提高电能质量非常必要。本文以动态电压恢复器（DynamicVoltageRestorer,DVR）为研究对象，首先介绍了研究DVR的目的意义和DVR的发展概况，阐述了其主电路结构和工作原理，并对主电路结构的选择以及参数的设计进行了理论分析。其次，在目前跌落电压特征量的检测方法中，基于瞬时无功功率理论的单相dq变换检测方法应用广泛，但需要考虑由单相电压虚构三相电压的问题。本文讨论了Hilbert变换检测法和小波变换检测法，并通过仿真比较，确定小波变换检测法具有较好的检测性能；对比了目前广泛使用的滞环控制和定时控制两种跟踪型PWM控制方式，选取定时控制的瞬时值比较方式作为DVR中PWM逆变器的控制方法。最后，在理论研究的基础上，应用MATLAB中的SimPowerSystems工具箱对DVR进行了建模仿真，对比了电网中发生电压跌落、电压上升和电压跌落并伴有谐波等几种电能质量问题时DVR的补偿性能。仿真结果证明了DVR所采用的检测方法和控制策略的正确性，且具有较好的补偿特性，且能够同时解决电网中的多种电能质量问题。关键词：电能质量；动态电压恢复器；电压跌落；MATLAB仿真-Ⅱ-AbstractWiththedevelopmentofmodernscienceandtechnology,thenonlinearloadsandpowerelectronicsequipmentarewidelyapplied.Thoseloadsaregenerallysensitivetoelectricaldisturbanceswhichmaycausethemtomalfunctionoreventofail.Amongvariouspowerinterruptionordisturbancefactors,voltagesagsarecurrentlythelargestcauseofdisruptioninpowersupplysystems.Voltagesagsareunpredictable,thiswillresultinconsiderableeconomiclosses.Therefore,it’sverynecessarythattheuseofcompensationdevicestoeliminatetheinstantaneousvoltagesagandimprovepowerquality.Thispapertakesthedynamicvoltagerestorerastheresearchobject.Firstly,thebackgroundandsignificationoftheresearchworkisintroduced,andthedomesticandoverseadevelopmentofDVRissummarized,andthenthesystemconfigurationandbasicoperationprinciplearediscussed，thechooseofDVRmaincircuitstructureandthedesignofthecircuitparametersareanalyzedonthetheory.Secondly,single-phasevoltagedqtransformdetectionmethodbasedoninstantaneousreactivepowertheoryiswidelyused，buttheconstructionofthree-phasevoltagebysingle-phaseneedbeconsidered.Thedetectionmethodbasedonhilberttransformandwavelettransformarediscussedandsimulatedtoensurethatthelatterhasbetterexcellentfunction.ThetwotracingPWMcontrolapproacheswhichhavebeenwidelyusedarediscussed,thetimer-controlhysteresisPWMcontrolmethodisfitontheDVRbetter.Finally,thesimulationmodeloftheDVRbasedonthetheoreticalanalysisisbuiltupwithSimPowerSystemsofMATLAB,andseveralkindsofvoltagesaginthesingle-phaseandthree-phasesystemaresimulatedrespectively.ThesimulationresultsshowthatthedetectionmethodandcontrolstrategywhichareusedinDVRareofagoodcompensationcharacteristics,andDVRcansolvemultiplepowerqualityproblemsinthepowersystems.Keywords:Powerquality,Dynamicvoltagerestorer,Voltagesag,MATLABsimulation兰州交通大学毕业设计(论文)-III-目录摘要......................................................................................................................IIIAbstract........................................................................................................................III1绪论.....................................................................................................................11.1电能质量问题概述..........................................................................................11.1.1电能质量概念....................................................................................................11.1.2电能质量问题分类..........................................................................................11.2电压跌落..........................................................................................................31.2.1电压跌落产生的原因......................................................................................31.2.2电压跌落的危害...............................................................................................41.2.3电压跌落的抑制方式......................................................................................41.3动态电压恢复器的研究与应用现状..............................................................51.3.1国外的研究现状..............................................................................................61.3.2国内的研究现状..............................................................................................61.4MATLAB/SIMULINK简介............................................................................71.5本论文的主要工作..........................................................................................72动态电压恢复器的工作原理与结构........................................................................92.1动态电压恢复器的基本结构与原理..............................................................92.2DVR的工作模式.............................................................................................92.3DVR的电压补偿策略...................................................................................103动态电压恢复器的主电路参数设计......................................................................123.1主电路的结构选择........................................................................................123.1.1逆变器的选择.................................................................................................123.1.2串联变压器.....................................................................................................123.1.3输出滤波器.....................................................................................................133.1.4直流储能单元的选取.................................................