基于电路等效的并网逆变器失稳分析与稳定控制
文档名：基于电路等效的并网逆变器失稳分析与稳定控制
摘要：以并网逆变器为功率接口的新能源发电系统在弱电网条件下易发生振荡失稳问题.该文将并网逆变器的控制回路可视化为电路元件组成的虚拟阻抗,基于该电路模型分析了弱电网条件下电流内环与锁相环交互作用导致并网逆变器振荡失稳的机理,在此基础上,提出了基于有源阻尼的稳定控制设计方法,并对不同有源阻尼控制的电路特性以及稳定性提升能力进行了对比分析.研究结果表明,针对锁相环引入负电阻造成的振荡失稳问题,阻抗-高通滤波器型有源阻尼控制策略具有更优的稳定性提升能力.最后通过PSCAD/EMTDC仿真和远宽StarSim控制器硬件在环实验对比了不同有源阻尼控制策略的振荡抑制效果,并验证了阻抗-高通滤波器型有源阻尼控制的动态性能.结果表明,所设计的稳定控制能够在200ms内有效抑制系统振荡,并且可实现在短路比为1的极弱电网条件下稳定运行.
Abstract：Therenewableenergypowergenerationsystemsthatutilizegrid-connectedinvertersasthepowerinterfacearepronetoinstabilityissueswhentheACgridisweak.Thefundamentalreasonforthewidebandoscillationphenomenonwhengrid-connectedinvertersareintegratedintoACgridsisnegativeresistance.Firstly,tounderstandthemechanismofthenegativeresistanceandproposetheeffectiveoscillationsuppressionmethods,thispapervisualizesthecurrent-innerloop,phase-lockedloop,voltagefeedforward,anddecouplingtermsofthegrid-connectedinverterintotheequivalentcircuitmodelinthedq-domain,modified-sequencedomainandpositive/negative-sequencedomain.Bystudyingtheinteractionofcontroldynamicswithinthesub-/super-synchronousfrequencyrange,thecircuitessenceofthenegativeresistanceisrevealed.Secondly,basedontheequivalentcircuitmodelofthegrid-connectedinverterandtheinherentessenceofthenegativeresistance,thedesignprinciplesofactivedampingcontrolareproposed.Additionally,theoptimallocationforimplementingactivedampingcontrolisexamined.Accordingtotheequivalentcircuitamongvariousactivedampingcontrols,theinvestigationisconductedtounderstandtheimpactofthesecontrolsonthenegativeresistancecharacteristics.Finally,theoscillationsuppressioneffectsofdifferentactivedampingcontrolstrategiesarecomparedthroughPSCAD/EMTDCsimulationsandStarSimcontrollerhardware-in-the-loopexperiments.Besides,thedynamicperformanceoftheimpedance-high-passfiltertypeactivedampingcontrolisvalidated.Itisdemonstratedthatthesystemoscillationcanbeeffectivelysuppressedwithin200msusingthedesignedcontrolmethod.Additionally,thegrid-connectedinverterremainsstableunderweakgridconditionswithSCR=1.Themainconclusionsofthispaperareasfollows:(1)Theinteractionbetweenthecurrentinnerloopandthephase-lockedloopofthegrid-connectedinverteristheprimarycausefortheemergenceofthenegativeresistanceintheq-axisequivalentcircuit.Thenegativeresistanceoftheq-axiscircuitresultsinthenegativeresistancecharacteristicinthetraditionalsequential-domainimpedance,particularlynearthefundamentalfrequency.Undertheweakgridscenarios,thenegativeresistancecharacteristicbecomesmorepronounced,elevatingtheriskofsub-/super-synchronousoscillations.(2)Basedonthecircuitmodelresultingfromtheinteractionbetweenthephase-lockedloopandcurrentinnerloop,thephase-lockedloopdeterminestheexistenceofnegativeresistanceanditsfrequencyrangecoverage.Themagnitudeofthenegativeresistanceisinfluencedbytheintegralcoefficientofthecurrentinnerloop.(3)Whendesigningtheactivedampingcontrolparameters,itisessentialtoenhancetheinductancecharacteristicsoftheactivedampingcontroltomitigatetheimpactofnegativeresistancecausedbytheintegralcoefficientofthecurrentinnerloop.Thus,thesystemoscillatorystabilitycanbeimproved.(4)Theband-passfilterandband-rejectionfilterarebeneficialforreducingnegativeresistancewithinthespecificfrequencyrange.Meanwhile,low-passfiltersareadvantageousformitigatingthehigh-frequencyoscillations,whereashigh-passfiltersareusefulforsuppressinglow-frequencyoscillations.Underthesameparameterconditions,theimpedance-highpassfilter-basedactivedampingcontrolproposedinthispaperdemonstratesabettersuppressioneffectonsub-/super-synchronousoscillations,resultinginanotableenhancementofthedynamicperformance.
作者：高磊 吕敬 马骏超 刘佳宁 蔡旭 Author：GaoLei LüJing MaJunchao LiuJianing CaiXu
作者单位：电力传输与功率变换控制教育部重点实验室(上海交通大学)上海200240国网浙江省电力有限公司电力科学研究院杭州310000
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(8)
分类号：TM721
关键词：并网逆变器电路等效振荡稳定性有源阻尼虚拟阻抗稳定控制
Keywords：Grid-connectedinverterimpedancecircuitequivalentoscillationstabilityactivedampingvirtualimpedancestabilitycontrol
机标分类号：TM46TM712TN751.2
在线出版日期：2024年4月29日
基金项目：国家自然科学基金，国网浙江省电力有限公司科技项目基于电路等效的并网逆变器失稳分析与稳定控制[
期刊论文]电工技术学报--2024, 39(8)高磊吕敬马骏超刘佳宁蔡旭以并网逆变器为功率接口的新能源发电系统在弱电网条件下易发生振荡失稳问题.该文将并网逆变器的控制回路可视化为电路元件组成的虚拟阻抗,基于该电路模型分析了弱电网条件下电流内环与锁相环交互作用导致并网逆变器振荡...参考文献和引证文献
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