文档名：大功率并网变流器离散域电流控制策略
摘要：兆瓦级大功率并网变流器的开关频率较低,延迟和离散化误差对控制性能影响较大,导致动态响应慢、电网背景谐波影响大等问题.因此,直接离散域控制系统设计成为必要.该文针对LCL滤波并网变流器建立离散域数学模型,并基于此提出桥臂侧电流和网侧电流融合的离散域电流控制器.同时,为了在不额外增加电流传感器和检测电路的情况下获取并网电流信息,设计电容电压微分器,实现网侧电流的估算,降低硬件复杂性和控制成本.研究表明,该文设计的离散域电流控制器,具有较好的动态性能和电网背景谐波抑制能力.最后,通过硬件在环半实物仿真系统对所提设计进行了实验验证.
Abstract：Forhigh-powergrid-connectedconverters,theswitchingfrequencyusuallyislow.Consequently,theadverseeffectsenforcedbythecontroldelayanddiscretizingerrorsareheavy.However,traditionalcurrentcontrolstrategiesgenerallyignoretheseeffects,reducingtheperformanceofthedesignedcontroller.Recently,somestrategieswerepresentedtocompensateforthecontroldelayandthediscretizingerrors.However,mostsufferfromlowdynamicresponseandhighsensitivitytothepowergridharmonics.Therefore,acurrentcontrolstrategycombiningthebridgearm-sideandthegrid-sidecurrentsisdesigneddirectlyinthediscrete-timedomain,andpole-zeroplacementisusedinsynchronouscoordinates.Meanwhile,adifferentiatortothecapacitorvoltageisintroducedtoestimatethegrid-sidecurrents.Consequently,hardwarecomplexityandthecorrespondingcontrolcostarereduced.Thediscrete-timemodeloftheconverterwithLCLisbuiltinsynchronouscoordinatesastheoutputfilter,includingthecomputationaldelay,firstly.Thecorrespondingstructureofthecombinedstate-spacecontrolschemeisasfollows:theharmoniccontrolloopofthegrid-sidecurrentsisconstructedandcombinedwiththefundamentalcurrentcontrollooponthebridgearm-sideusingthefullstate-feedbackcontrol.Andthen,theintegralcontrollerisintroducedforimproveddisturbancerejection,andthereference-feedforwardcontrollerisdesignedtoincreasethereference-trackingdynamicperformance.Consequently,theclosed-looptransferfunctionofthesystemisobtainedbasedonthediscrete-timemodelandthecontrolscheme.Thenthestatefeedbackfunctionmatrixandthefeedforwardmoduleareoptimizedbasedonthepole-zeroplacement.Finally,adifferentiatorisintroducedtoestimatethegrid-sidecurrents,reducingthehardwarecost.Experimentresultsbasedonahardware-in-loopsimulatorshowthattheresponsetimeofthebridgearm-sidecurrentstoa1000Astep-upchangeisabout4.5ms;therecoverytimeofthebridgearm-sidecurrentsfacingagrid-voltagedipof0.4(pu)isabout10ms;andthetotalharmonicdistortionofthegrid-sidecurrentsis2.28%,belowthe5%limitgiveninstandards,inthecircumstancesof6%fifthandseventhharmoniccomponentsappearinginthegridvoltage.Finally,toverifytherobustnessoftheproposedstrategytotheparameterdeviations,theactualsystemparametersaredeviatedartificiallyfromtheirnominalvalues.Theresultsshowthattheproposedstrategycanoperatesatisfactorilyintherangeof±40%parameterdeviations,andtheinfluenceoftheparameterdeviationsislow.Thefollowingconclusionscanbedrawnfromtheexperimentresults:(1)Comparedwiththetypicaldiscrete-timestate-spacecontrolstrategy,theproposedstrategykeepsthesamedynamicperformancewhileimprovingthecapabilityofrejectingthegridharmonicdisturbance.(2)Theproposedcontrolstrategysimplifiesthedesigncomplexitybasedonthedirectpole-zeroplacementandincreasesfreedomdegreesbycombiningthedesignoffundamentalcurrentandharmoniccontrolloops.(3)Thedifferentiatortothecapacitorvoltageisdesignedtoacquiregrid-sidecurrentswithoutadditionalcurrentsensorsandthecorrespondingsamplingcircuit,reducingthehardwarecomplexityandthecost.
作者：王旭 杨淑英 李典 张兴Author：WangXu YangShuying LiDian ZhangXing
作者单位：合肥工业大学可再生能源接入电网技术国家地方联合工程实验室合肥230009
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(8)
分类号：TM464
关键词：LCL型并网变流器 低开关频率 离散域控制 背景谐波
Keywords：Grid-connectedconverterwithLCL lowswitchingfrequency discrete-timecontrol gridharmonics
机标分类号：TM464TM351TQ320.66+2
在线出版日期：2024年4月29日
基金项目：安徽省科技重大专项资助项目大功率并网变流器离散域电流控制策略[
期刊论文] 电工技术学报--2024, 39(8)王旭 杨淑英 李典 张兴兆瓦级大功率并网变流器的开关频率较低,延迟和离散化误差对控制性能影响较大,导致动态响应慢、电网背景谐波影响大等问题.因此,直接离散域控制系统设计成为必要.该文针对LCL滤波并网变流器建立离散域数学模型,并基于此提...参考文献和引证文献
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大功率并网变流器离散域电流控制策略 Discrete-Time Domain Current Control Strategy for High Power Grid-Connected Converters
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