光伏与微型燃气轮机混合微网建模及控制策略研究

光伏与微型燃气轮机混合微网建模及控制策略研究重庆大学硕士学位论文学生姓名：邓浩指导教师：周念成副教授专业：电气工程学科门类：工学重庆大学电气工程学院二O一一年五月ResearchonModelingandControlStrategiesofPVandMicroturbineHybridMicrogridAThesisSubmittedtoChongqingUniversityinPartialFulfillmentoftheRequirementfortheDegreeofMasterofEngineeringByDengHaoSupervisedbyAssociate.Prof.ZhouNianchengMajor:ElectricalEngineeringCollegeofElectricalEngineeringofChongqingUniversity,Chongqing,ChinaMay,2011中文摘要I摘要本论文受重庆市自然科学基金（CSTC2009BB6190）和输配电装备及系统安全与新技术国家重点实验室自主研究项目（2007DA10512709208）的资助。随着能源危机和环境污染的日益严重，微网技术作为一种可行的解决方案，已经成为研究热点。光伏微源以资源丰富、分布广泛、清洁等特点成为最具开发潜力的可再生能源之一。由于光伏发电具有明显间歇性，输出功率受天气变化影响较大，加入可控微源或分布式储能与光伏发电互补形成混合微网，能提高光伏发电的可靠性。在可控微源中，微型燃气轮机发电能同时供应冷热电负荷，具有排放少、效率高及燃料适应性好等优点，已成为冷热电联供微网中最有发展前景的分布式电源，因此研究光伏与微型燃气轮机组成的混合微网运行特性和控制策略具有重要的意义。论文主要内容如下：①分析了光伏发电和光伏逆变器原理，研究了光伏发电运行特性及其影响因素。根据光伏阵列数学模型，开发用户定义的光伏阵列与最大功率跟踪控制元件，通过输出电流信号来驱动一恒流源元件，以此模拟实际光伏阵列装置，采用电导增量法实现最大功率跟踪（MPPT）控制。搭建了光伏发电系统模型，验证了光伏阵列的I-V/P-V特性曲线，分析了光照及温度变化对系统所传输功率的影响。②基于微型燃气轮机与电力电子换流装置工作原理和数学模型，根据微网并网和孤岛运行特性要求，对采用双脉宽调制（PWM）变换器结构的微型燃气轮机发电系统进行了整体建模。为控制交直交变换器中电容电压，整流器采用PWM恒压控制；考虑基本的V/F和PQ控制策略，分别实现并网和孤岛状态下逆变器的控制算法。在动态负荷条件下对微型燃气轮机发电系统运行特性进行了仿真分析。③在分析光伏发电和微型燃气轮机动态模型及运行特性的基础上，研究了采用变步长时间序列法预测的光伏与微型燃气轮机混合微网控制策略。混合微网并网运行时，利用可控的微型燃气轮机平滑光伏功率波动，使混合微网成为一个可调度的功率源；孤岛运行时，储能蓄电池与微型燃气轮机共同补偿光伏与负荷功率的差额，实现微网的稳定运行。根据光伏与负荷功率的频率特性，提出了采用变步长时间序列法预测光伏与负荷等效功率曲线，克服微型燃气轮机响应速度慢的缺点。为了提高蓄电池的运行效率和工作寿命，提出了模块化的储能蓄电池管理模型，保证了混合微网运行的可靠性。④在PSCAD/EMTDC中建立了光伏与微型燃气轮机混合微网仿真模型，在Matlab中实现控制算法，通过混合仿真，验证了本文提出的理论和方法的正确性。重庆大学硕士学位论文II仿真研究了并网、孤岛和并网与孤岛转换三种状态下的运行特性，分析了变步长时间序列法对微网联络线功率波动的影响和蓄电池模块化管理的运行状态。关键词：光伏，微型燃气轮机，建模，控制策略，时间序列法英文摘要IIIABSTRACTThisthesiswassupportedbyNaturalScienceFoundationofChongqing(CSTC2009BB6190)andindependentresearchprojectofStateKeyLaboratoryofPowerTransmissionEquipment&SystemSecurityandNewTechnology(2007DA10512709208).Withtheworseningofenergycrisisandenvironmentpollution,microgridtechnologyhasbecomeahottopicasafeasiblesolution.Themicrosourceofphotovoltaicbecomesoneofrenewableenergysourceswiththegreatestdevelopmentpotentialbecauseofabundance,widedistribution,cleannessandsoon.BecausethePVgenerationisobviouslyintermittent,theoutputpowerisgreatlyinfluencedbythevariableweather.InordertoimprovethereliabilityofPVgeneration,thecontrollablemicrosourceordistributedstorageisaddedinwiththePVgenerationtoformhybridmicrogrid.Amongthecontrollablemicrosource,microturbinecansupplyhotandcoldloadatthesametime.Withtheadvantagesoflowemission,highefficiencyandbetterfueladaptability,microturbinehasbecomethemostpromisingdistributedpowerinthecombinedcoolingheatingandpowermicrogrid.Therefore,ithasgreatsignificancetoresearchtheoperatingcharacteristicsandcontrolstrategyofthehybridmicrogridcomposedofPVandmicroturbine.Themaincontentisasfollows:①PVgenerationandPVinverterprincipleisanalyzedtostudytheoperatingcharacteristicsandinfluencefactorofPVgeneration.Auser-designedPVarrayandmaximumpowerpointtrackingcontrolmodelaredeveloped.Aconstant-currentsourceelectricalmodelcanbedrivenbythecurrentoutputsignalofthePVarraycontrol,bywhicharealPVarrayequipmentcanbesimulated.TheincrementalconductancemethodisusedtoachieveMPPTcontrol.ThePVgenerationsystemmodelisbuildedtoverifytheI-VandP-VcharacteristiccurveofPVarray.Theinfluenceofilluminationandtemperaturechangeonthesystemtransmissionpowerisanalyzed.②Basedontheworkingprincipleandmathematicalmodelofmicroturbineanditspowerelectronicconverter,accordingtothemicrogridcharacteristicsingridandislandstate,anoverallmodelofamicroturbinegenerationsystemwithdoublePWMconvertersisestablished.InordertomaintaintheDCvoltage,rectifierusesaconstantvoltagecontrolmethod.BasedonV/FandPQcontrolstrategies,thecontrolalgorithmofinverterisachievedingridandislandstate.Theoperatingcharacteristicsof重庆大学硕士学位论文IVmicroturbinegenerationsystemwithdynamicloadisanalyzed.③ThedynamicmodelandoperatingcharacteristicsofPVandmicroturbinegenerationsystemareanalyzed，andthecontrolstrategyofPVandmicroturbinehybridmicrogridusingthetimeseriesmethodwithvariablestepsisresearched.Whenthemicrogridoperatesonthegrid-connectedmode，thecontrollablemicroturbineisusedtosmooththephotovoltaicpowerfluctuationandmakethehybridmicrosourcebecomingascheduledpowersource.Whenthemicrogridoperatesontheislandingmode，thestoragebatterywhichresponsestherapidlychangingpowertogetherwithmicroturbinecompensatedthepowerdifferencebetweenPVandload,andthiscanrealizethestableoperationofmicrogird.ThetimeseriesmethodwithvariablestepsisadoptedtopredictthepowerofPVandloadaccordingtotheirfrequencycharacteristics,andthemicroturbine’sdisadvantageofslowresponseisovercome.Inordertoimprovetheefficiencyandlifespanofbatteries,amodularcontrolmodeforbatterymanagementisproposedtoguaranteethereliabilityofhybridmicrogrid.④ThePVandmicroturbinehybridmicrogridsimulationmodelisestablishedinPSCAD/EMTDC,thecontrolalgorithmicisachievedinMatlab.Itverifiesthevalidityoftheproposedtheoryandmethodthroughhybridsimulation.Theoperatingcharacteristicsinthreestatecontainedgrid-connection,islandingandmodeswitchingareanalyzed.Theinfluenceofvariablesteptimeseriesmethodonthepowerfluctuationofmicrogri