外文翻译-基于Matlab LabVIEW的变速恒频风力发电培训系统研究

英文原文ResearchofVSCFWindPowerGenerationTrainingSystemBasedonMatlab/LabVIEW*AbstractThepaperoffersawindturbinetrainingsystem,whichhassupervisorylayerandcontrollayer.ThesupervisorylayerisbasedonAmericanNICompanysgraphicalsoftware-LabVIEWtosetupthemonitoringinterface.ThecontrollayerisbasedonMatlab/Simulinksoftwaretosimulatethewindpowergenerationsystemmodel.WithresearchingthemathematicmodelofwindturbineandanalyzingcontrolstrategyofDouble-fedinductiongenerator,avariable-speedconstant-frequency(VSCF)windpowergenerationtrainingsystemispresented.Themainoperationsofwindpowergenerationsystemhavebeenimplementedincludingcutting-incontrol,maximumpowerpointtracking(MPPT)atlowwindspeedandpowercontrol/variablepitchcontrolattheratedwindspeed.ThecorrespondingcurvesinsimulinkandLabVIEWplatformsareacquired.Andbycomparingthemthecorrectnessandfeasibilityofthetrainingsystemareproved.IndexTerms-windpowergeneration;LaboratoryVirtualInstrument;Double-fedinductiongenerator(DFIG);variable-speedconstant-frequency;I.INTRODUCTIONWindenergyasaninexhaustiblesupplyofrenewableresourceshasbecamethehotspotofinternationalcommunication.Atpresent,thevariable-speedconstant-frequencysystemiswidelyusedinwindpowergeneration.Ithasalotofadvantagessuchashighwindenergyutilizationcoefficient,security,andreliability.Becauseoftheseadvantages,windpowergenerationunithasbeenwidelyused.Moreandmorewindfarmoperatorsareneededtoacquiretheprofessionalknowledge.However,itisnotonlyaffectingthepowerproduction,butalsobeingdangerous,ifthestafftrainingonrealpowerunit.Therefore,thesoftwaretrainingsystemofwindpowergenerationbecomesanurgentneed.Besidesithasbeenwidelyrecognizedthattheuseofsimulationsystemissuitableforvocationaltraining.ThispaperpresentsatrainingsysteminwhichthecontrollayerisbasedonMatlab/Simulink9,13andthesupervisorylayerisaccordingtoLabVIEW.Theoperationresultsshowthatthetrainingsystemprovidesagoodtoolforimprovingthewindpowerknowledgeandoperationskillsofoperatorandotherlearners.II.SOFTWAREINTRODUCTIONA.BriefintroductionofLabVIEWandSimulinkLabVIEWisagraphicalprogramminglanguage.Asastandarddataacquisitionandinstrumentcontrolsoftware,itiswidelyacceptedbyindustry,academiaandresearchlaboratories.Itisspecificallydesignedtotakemeasurements,analyzedata,andpresentresultstotheuser.Moreover,LabVIEWhassuchaversatilegraphicaluserinterfaceandissoeasytoprogramwith,itisalsoidealforsimulations,presentationofideas,generalprogramming,oreventeachingbasicprogrammingconcepts.Matlabistheinteractivecomputingsoftware.ItismainlyorientedtoEngineeringandscientific.SimulinkisanadditionalcomponentofMatlab.Itcanbeusedtomodel,analysisandsimulatedynamicsystemswhichincludecontinuoussystems,discretetimesystems,hybridsystemsandetc.B.LabVIEW&SimulinkcommunicationThissystemisbasedontheSimulink/LabVIEW.Howtorealizetheinteractionoftwosoftwaresisvitalimportance.Soanexperimentisadoptedtoprovetheconvenientandtheinteraction.Concretestepsareasfollows:1)Atestmodel:Asshowninfig.1,asimulinkoff-linemodelissetedup.ThecommunicationbetweenLabVIEWandMatlab/SimulinkisaccomplishedbyaspecificallyModule-SignalProbewhichisprovidedbyNICompany.OthermodulesareprovidedbySimulink.Theysupportdragginganddouble-clickingtheiricontochangeparameters.2)Communicationpropertiesset:TheMatlab/Simulinkispseudo-real-timesimulationsoftware.However,thetrainingsystemrequiresareal-timesimulation.Forthesefactors,areal-timeapplicationisadoptedwhichallowsthesimulationsystembeingsynchronouswitharunningclock.Stepsareasfollows:Firstly,intheSimulinkwindow,selectConfigurationParameters/Solvertosetsimulationstart/stoptimeandsolveroptions.Secondly,chooseReal-TimeWorkshoptabtoselectsReal-TimeWindowsTargetasthetargetenvironmentofsystem.Andthetargetfileisgenerated.Thirdly,atReal-TimeWorkshoptab,clickBuildbuttontocreateCcode.Bycompilerlink,theexecutableapplicationsaregenerated,andcouldbedownloadedtothetargetmachine.3)CommunicationwithLabVIEW:Aftertheabovesteps,thesuperior-inferiorcommunicationhasbeenimplemented.ThedataofsimulinkcanbetransformedtothescopeofLabVIEWviathesignalprobe.Thegraphicaluserinterfaceisshowninfig.2.IIITHEMATHEMATICALMODELOF.VSCFWINDPOWERGENERATIONA.WindTurbineSimulationModelWindturbineistheprimarycomponentofwindenergyconversionsystemwhichconvertsthewindenergyintomechanicalenergy.Accordingtothewell-knownBetztheoryandaerodynamics,windenergycouldnotbeallabsorbedbythewindturbinecompletely.Theoutputpowerofwindturbineisdeterminedbyalotoffactors,suchaspowercoefficient(Cp),airdensity(),radiusofthewindwheel(R)andwindspeed(v).Thepowercapturedbythewindturbineisobtainedas:32vRCPpm），（1）WhereCpisanonlinearfunctionofthepitchangle()andthetip-speedratio().Itishighlydependentontheconstructivefeaturesandcharacteristicsoftheturbine.AnempiricalformulaisintroducedtodescribeCpasshowninequation(2).)3(0184.3.15)(sin)067.4(),pC（2）vR（3）Where:istheangularvelocityofwindturbine,w1)TrackingtheLargestWindEnergy:Forvariablespeedoperation,eachwindspeedhasamaximumpowerpoint.Byequations(1)(3)themaximumoutputpowerofwindturbineisobtainedas:350maxax)1(),(2outpRCP（4）Where:istheinstallationangleofwindturbine;istheoptimaltipspeed0outratio;maxisthelargestwindenergyutilizationcoefficient.CpmaxWhenthewindturbineisrunningbelowtheratedwindspeed,theoutputpowerofDFIGdoesnotreachtheratedpoint.Windenergyshouldbeconvertedintoelectricalenergyasmuchaspossible.TheMaximumPowerPointTracking(MPPT)strategyisintroducedtotrackthelargestwindenergy.sP1max（5）Thereferenceactivepowerofstatorcanbeobtainedinequation(5).Bytrackingtheactivepowersetpoint,themaximumpowerpointisacquired.12)PitchAngleControl:Whenthewindspeedsexceededtherated,theoutputpowerofDFIGshouldberestrictedtotheratedvalue.Thisisachievedbyincreasingthepitchangle.Asaresult,theutilizationratioofwindpowerreduces,andtheoutputpowercorrespondinglydecreases.Thevariablepitchcontrolstrategyisadoptedathigh-windspeed,asshowninFig.3.Thecontrollerisatypicalproportionintegrationcontroller.AccordingtotheerrorbetweenthereferenceandthefeedbackpowervaluePIcontrolleroutputsareferenceincrementvalueofbladepitchangle.Becausethebladesresponsetothevariable-pitchcommandsneedstime,thispaperabstractsthepitchcontrolsystemasaninertialelement.Theequationsareasfollows:dt（6）0（7）Where:istheinertialtimeconstant,isthepitchangleincrement.B.DFIGSimulationModelDFIGisoneofthemaingeneratorsinthewindfarms,whichproducesconstantfrequencypowertothegrid.TheexcitationcurrentoftherotorissuppliedbyPWMconverterinwhichenergycanflowbidirectional.ForatypicalDFIG,thepowerconvertersareconnectedtotherotor.Becauseofthesliplimitation,thecaptureoftheconverterformsabout25%to30%ofthemachineratedcapture.ThedynamicmathematicalmodelofDFIGcanbederivedinthreephasesstaticcoordinatesandsynchronousrotatingdqcoordinates.VectorformofDFIGindqcoordinatesareanalyzedandcontrolled.Theequationsareasfollows(statorbehavesasageneratorandrotorbehavesasamotor).statorvoltageequations:qsdsqsqsdPiRu1（8）Rotorvoltageequations:qrdrqrrdiu1（9）Statorfluxsequations:qrmsqsddiL（10）Rotorfluxsequations:qrsmqrddiL（11）Torqueequation:)()(drqsrdsmnqsdsqneiiPiiPT(12)Equations(8)to(13)aresetofdifferentialequationsmakingupofafifth-ordermodelwhichdescribesthedynamicbehaviorofDFIG.Thevoltages,currentsandfluxlinkagesareexpressedbythed-axisandq-axiscomponentsinsynchronousrotatingreferenceframe.Intheactualwindfarm,whenthewindspeedexceedsthestartwindspeed,cutting-incontroliscarriedout.Ifdirectlyconnectedtogrid,atremendousimpactcurrentisproducedwhichwillaffecttheservicelifeofDFIGseriously.Meanwhilethevoltagefluctuationiscaused.DFIGisexactlyrunningatsynchronousspeedaftercutting-ingrid.Thus,cutting-incontrolstrategyisintroducedinthispapertoeliminatetheproblems.Beforenoloadcutting-in,thecontrolinformationisgotnotonlyfromgridside,butalsofromstatorside.Thecontrolstrategyisrelativelycomplex.Therefore,theideaofrespectivemodelingandtimesharingsimulationisadoptedtoimplementsimulationsofthewholeprocess.Inthewayofcutting-in,theno-loadandon-loadmodelsarewidelyused,wheretheon-loadmodelisnamedtheDFIGmodelinthispaper.InDFIGmodel,neglecttheinfluenceofthestatorfluxlinkagestransientprocessandorientthed-axisofthesynchronousframetothedirectionofthestatorfluxvector.Theequationsareasfollows:sdqsdsu,0,(13)Thephasedifferencebetweenthestatorvoltagevectorandthestatorfluxvectoris90,asshowninFig.4.Whereisthesynchronousangularvelocityofthegrid;1istheelectricangularvelocityoftherotor.rSubstitutingintoequation(13),therealandreactivepowersusqds,0ofstatoraregivenas:dsqiuQP1(14)Thestatoractivepower-P1isproportionaltotheq-axisstatorcurrent,Theiqsreactivepower-Q1isproportionaltothed-axisstatorcurrent.Inthatcase,dsDecouplingcontroloftheactiveandreactivepowerisimplemented.Substitutingintoequation(10)andequation(9),therotor,0qsdsvoltageequationsaregivenas:qrqrrdduu(15)Inno-loadmodel,thereisnocurrentinDFIGstatorwindings.Sothestatorcurrentofd,qaxis(ids,iqs)arezero.Substitutingids=iqs=0inequations(8)to(13),themathematicmodelofDFIGareobtained.Andtheactualstatorvoltagecanbeeasilycalculated.Inthiscondition,equation(8)canbesimplifiedasfollows.dsqsqsssdstu1(16)Ifthefrequency,amplitudeandphaseerrorsbetweenthestatorvoltageandvoltageofpowergridfallintotheallowablerange,thecutting-incontrolcanbecarriedout.AftertheDFIGcutinthegridsuccessfully,theon-loadmodelanditscontrolstrategybegintowork.Becauseoftheno-loadmodelandon-loadmodelaredifferent.Inordertoswitchthetwosystemssmoothly,aswitchingsystemisdesignedasshowninfig.5.Thepoint1correspondstocutting-incontrolsubsystem.Atthattime,theDFIGsoutputpoweraswellasthestatorcurrent(ids,iqs)arezero.Whenswitchedtothepoint2thepowercontrolsubsystembeginstowork.IV.VSCFWINDPOWERGENERATIONSIMULATIONIMPLEMENTATIOIntermsofdifferentwindconditions,theoperationstateofVSCFwindpowergenerationsystemscanbedividedintothreeregions.Theyarethestartingstage,thelowwindstageandthehighwindspeedstage.Eachregionhasitsowncontrolmissionandcontrolstrategy.Thespecificprogramflowdiagramisshowninfig.6.AccordingtothemathematicalmodelsofthewindturbineandDFIGabove,thesimulationmodelofthetrainingsystemisconstructedinthesimulinkplatformofthematlabsoftwareasshowninfig.7.Therearefoursubsystems,bythenameofwindturbinemodel,DFIGno-loadmodel,DFIGmodel,andVariablepitchcontrolmodel.Beforeconnectingwithpowergrid,DFIGno-loadmodelisenabled,DFIGmodelisholdon.Onthecontrary,afterconnectionwiththepowergridtheDFIGmodelwillbeineffect,buttheno-loadmodelwillbeprohibited.Whenwindspeedislowerthantheratedwindspeed,theMPPTstrategyworkstokeeptheoptimaltipspeedratioandgainthemaximumwindenergy.Whenthespeedishigherthantherated,thevariablepitchcontrolstrategyworks.Itincreasespitchangle,limitstheabsorptionofwindenergy,andkeepstheDFIGpowerattheratedpoint.Duringthesimulation,theinitialvalueofwindspeedis5m/s,at3sthespeedstepsto10m/s.Before3sthewindspeedhadexceededthecutting-inwindspeedwhichis3m/sinthissystem.Itmeetstherequirementsofcutting-in.Thecutting-incontrolstrategybeginstoregulatethestatorvoltage.Whentheerrorofthevoltagemeattherequirement.TheDFIGwillcutintothegrid.ThecomparisonofthestatorvoltageandvoltageofpowergridisshowninFig.8.Fig.8Thewaveformofcutting-insystemFig.9,10areofflinesimulationcurvesoftheVSCFwindpowergenerationinsimulink.Beforecutting-ingrid,DFIGrunsattheidlingstate.Itsoutputpoweriszero.Aftercutting-incontrol,DFIGsmoothlyswitchestotheloadmodel.In03s,thewindspeedis5m/s.TheMPPTcontrolstrategyisappliedtokeepthepowercoefficientatthemaximumpoint.Asshowninfig.9,Cpisatpeakvalueandthepitchanglemaintainsatafixedvalue.Inthemeantime,DFIGrunsatSub-synchronizationstatuswhichhasbeenshowninfig.10(a).Atthemomentof3s,thewindspeedstepsto10m/s.Itishigherthantheratedwindspeed.Therotatespeedoftherotorexceedsthesynchro-speedandoperatesintheSuper-synchronousstatus.Atthesametimethepitchcontroldevicebeginstowork.Byadjustingthebladepitch,theairflowonthebladeattackedanglechangesandtheaerodynamicpowerofwindturbineislimitedtothenormallevel.ThustheoutputpowerofDFIGwillmaintainattheratedvalue.Howeverthewindpowerutilizationcoefficientdecreases.Fig.11showsthehuman-machineinterfacethatiswrittenbyLabVIEW.ItisthemainHMIofthetrainingsystemwhichcontainsdifferentpartsoftheDFIGpowerunitandsomekeyparameters.Thesimulinkmodelwhichhasbeenintroducedabovecanberecognizedasthevirtualequipment.ThesupervisoryandcontrollayercouldbeconnectedbySITConnectionManagerofLabVIEW.Thereal-timesimulationcurvesofVSCFwindpowergenerationtrainingsystemareshowninFig.12.Caparisoningwithfig.9andfig.10,thetrendofcurvesisthesame.Theresultsprovetheinteractivityofthetwolayersiscorrectness.Becausethetimeofsimulationiscontrollable;usercansetthetrainingtimetomeetstherequirementsoftheactualtrainingsystem.V.CONCLUSIONThispapercombinesSimulinkmodelwithLabVIEWinterfacetoimplementVSCFwindpowergenerationtrainingsystem.Incontrollayer,thesimulationmodelinthesimulinkplatformisproposed,whichisbasedontheactualwindpowergeneration.Ithelpsthestafftounderstandtheoperationconditionsoftheunit,andbefamiliarwiththeperformance.Italsohelpsthedevelopmentengineerstolearnnewalgorithms.Becausetherearealotofdangeranddifficultyforlearningintheactualwindpowerunit,suchasthedangerofarbitrarilychangingtheparameters,doingwrongoperations,thedifficultyoflearningwindturbinebydirectlycheckingthenacelleunderpooroutdoorenvironmentandact.Insupervisorylayer,avividHMIisprovidedtothewindpowertrainingsystem,whichhelpstraineetoquicklygraspthebasicknowledgeofwindpowergeneration,andfamiliarizewiththeworkenvironmentandemergencyhandling.ACKNOWLEDGMENTThisworkiscarriedoutasapartoftheNationalScienceFoundationofChina(50677021)sponsoredbyDetectionTechnologyandAutomationDevicesLabofNorthChinaElectricPowerUniversity.中文翻译基于Matlab/LabVIEW的变速恒频风力发电培训系统研究摘要：本文提供了一个风电场的培训系统，它有监控层和控制层组成。监控层是基于美国NI公司的图形软件LabVIEW的设立监控接口。控制层是基于Matlab/Simulink软件来模拟风力发电系统模型。通过研究风力机的数学模型和双馈感应电机的控制策略，变速恒频风力发电培训系统被建立。变速恒频发电系统主要包括并网控制，在低风速下的最大风能捕捉及不同风速下的变桨距控制。相应的曲线由Simulink和LabVIEW平台获得。通过对它们的比较，证实了系统的正确性与可行性。关键词：风力发电；实验室虚拟仪器；双馈感应电机；变速恒频引言风能作为一种取之不尽，用之不竭的可再生资源，已经成为国际关注的热点。目前，变速恒频系统已被广泛的用于风力发电。它有许多优点，如较高的风能利用率、安全、可靠，由于这些优点，风力发电机组被广泛的应用。越来越多的风电场运营商需要去获得更多的专业知识。因为，对于现实的风电场工作人员的培训，它不仅影响风电的产量，也被认为是危险的。因此，风力发电的软件培训已经成为迫切需要。现在被广泛认可的职业培训是仿真系统的应用。本文所介绍的培训系统，控制层是基于Matlab/Simulink,监控层是基于LabVIEW。运行结果表明，此培训系统是一个为经营者和其他学习者提高其风力发电知识及操作技能的好工具。软件介绍ALabVIEW和Simulink的简介LabVIEW是一种图形化编程语言。作为一个标准的数据采集和设备控制软件，已被工业界，学术界及研究实验室所接受。它经过专门的设计进行测量、数据分析，将结果传递给用户。此外，LabVIEW有这样一个多功能的图形用户界面，易于编程及仿真。Matlab是交互式计算软件。它主要是面向工程和科学运算。Simulink是Matlab的一个附加的组件。它可以用来建模、分析及仿真其中包括连续系统，离散时间系统，混合动力系统等。BLabVIEW和Simulink的实时通讯该系统基于Simulink/LabVIEW。如何实现两个软件的交互是至关重要的。所以我们我们通过实验来证明它们的便捷性与交互性。其具体步骤如下：1）测试模式：如图1所示，一个Simulink的离线模型被建立。Matlab和LabVIEW之间的联系由NI公司提供的一个叫信号探针的特别单元获得。其它单元由Simulink提供。他们支持拖放，双击其图标可以更改参数。2）通讯属性：MATLAB/Simulink的是伪实时仿真软件。然而，培训系统需要实时仿真。由于这些因素的存在，因此要创建实时应用，让仿真系统与一个实时时钟同步运行。步骤如下：首先，在Simulink的窗口中，选择ConfigurationParameters中的Solver选项卡来设定仿真的起始时间及步长，以及对应模式下的仿真算法。其次，选择Real-TimeWorkShop选项卡，选择Real-TimeWorkShopTarget作为系统实时仿真的目标环境。第三，在Real-TimeWorkShop选项卡下，点击“Build”按钮，创建“C”代码。并对其进行编译、链接生成可执行的目标应用程序，然后将其下载到目标机上。3）与LabVIEW的通信：经过上述步骤，低一级的联络已经生成，Simulink里的数据可以通过信号探针传递到LabVIEW的示波器中。图形用户界面如图2所示。变速恒频风力发电系统的数学模型A.风力机模型风力机是风力发电系统实现能量转换的首要部件，它将风能转换为机械能。根据著名的贝兹理论和空气动力学，风能不可能完全被风力机所吸收。风力机的输出功率由许多因素决定，如风能利用率，空气密度，风机风叶半径，风速等。由风力机捕获的风能可以由下式来表示：32vRCPpm），（1）其中风能利用系数是桨距角和叶尖速比的非线性函数。它取决于风力机的构造及特性。我们通过公式来描述，如图等式2所示：p)3(0184.3.15)(sin)067.4(),pC（2）vR（3）其中为风轮角速度。w1）最大风能追踪：转速不同，风力机输出功率不同，但总有一个固定的最佳转速点，通过等式（1）和（3），我们可以得到风力机的最大输出功率为：350maxax)1(),(2outpRCP（4）其中：为风机安装角，为最佳叶尖速比，为最大风0outpmax能利用系数。当风力机低于额定风速运行时，双馈感应电机没有达到额定的输出功率。风能尽可能的被转换为电能，最大功率点追踪用来捕获最大风能。sP1max（5）定子参考有功功率可用等式（5）来表示，通过跟踪有功功率设定点1，最大功率点可以被获得。P12）变桨距控制：当风速超过额定值时，双馈感应电机的输出功率应该被限制在额定值，可以通过增大桨距角来实现。这样，风能的利用率降低，电机的输出功率也相应的降低。变桨距控制是在高风速时采用的，如图3所示。控制器是典型的比例积分控制器，由功率的参考值和反馈值的差值，PI控制器输出一个桨距角的参考增量值。由于从指令的发出到桨叶输出相应的角度需要一定的时间，所以可以将变桨距系统抽象成一个惯性环节，等式如下：dt（6）0（7）其中：为惯性时间常数，为桨距角的实际变化量。B.双馈感应电机仿真模型双馈感应电机是风电场中主要的发电机之一，它为电网提供恒频的电能，转子的励磁电流有PWM变换器提供，可以实现能量的双向流动。对于一个典型的双馈感应电机，能量变化器被连接到转子侧。双馈电机的动态数学模型可有三相静止坐标系和两相同步旋转坐标系dq得到，双馈电机在坐标系下的矢量形式易于分析和控制。方程如下（定子dq采用发电机，转子采用电动机）statorvoltageequations:qsdsqsqsdPiRu1（8）Rotorvoltageequations:qrdrqrrdiu1（9）Statorfluxsequations:qrmsqsddiL（10）Rotorfluxsequations:qrsmqrddiL（11）Torqueequation:)()(drqsrdsmnqsdsqneiiPiiPT(12)等式（8）到（13）描述了双馈电机的动态行为，电压、电流和磁链之间的联系由两相旋转同步坐标系下的轴和轴分量组成。在实际的风电场中，当风速达到风力机的启动风速时，并网控制被执行，如果直接并网，会对电网产生较大的电流冲击，损坏发电机，同时电网电压将大幅的波动，双馈电机在并网后以同步速运行，因此，并网控制策略被介绍以消除此类问题。在空载并网前，控制信息不仅从网侧获得，也从定子侧获得。控制策略相当复杂，因此各自的模型被建立以实现整个仿真的进程。在并网的过程中，空载和带载模型被广泛的应用，在本文中，带载模型被称为双馈电机模型。在双馈电机模型中，忽略定子磁链瞬态过程的影响，以同步坐标系下的轴方向为定