外文翻译-基于DSP控制器的动态电压恢复器（DVR）序列分析

英文原分SequenceanalysisbasedDSPcontrollerforDynamicVoltageRestorer(DVR)JayantiN.G.,MalabikaBasu*,IurieAxente,KevinGaughanandMichaelF.ConlonSchoolofElectricalEngineeringSystemsDublinInstituteofTechnologyAbstractThepaperexaminesthebehaviourofaDynamicVoltageRestorer(DVR)underbalanced/unbalancedsupplyvoltagesagcondition,andrestrictedDVRinjectioncapability(e.g.limitedto50%ofthesupplyvoltageinjection).SequencecomponentsofthesupplyvoltageareextractedtogeneratethereferenceinjectedvoltagefortheDVR.Thecontroldeterminesthemaximumpossiblepositivesequenceinjectionwithinthecapacityofthecompensatortoachievebalancedvoltageconditionsattheloadterminals.Thecontrolisverifiedthroughsimulationandexperimentation.ThecontrolalgorithmhasbeenimplementedinaTI320F2812fixedpointDSPandtheeffectivenessofthecontrollerisverifiedinathree-phase,10kVADVRlaboratoryprototype.Inathree-phase,240Vsystem,balancedsagandsagwithmagnitudeandphaseunbalancehavebeencreated,whichissuccessfullycompensatedbytheDVRwiththeproposedcontroller.I.INTRODUCTIONTheDynamicvoltagerestorer(DVR)offerssensitivevoltagecustomersdynamicprotectionagainstsystemvoltagedisturbancesoriginatingfromtheincomingtransmission/distributionsystem.DVRscouldalsoformtheseriescompensatorpartofUnifiedPowerQualityConditioners(UPQC)toservetheabovepurpose1.TypicallyaDVR/UPQCisinstalledattheserviceentrypointofsensitivevoltagezonetocompensateforvoltagedisturbanceslikesag/swellorunbalance,suchthatthevoltageacrossacriticalloadterminalisperfectlyregulated3-6.Inthispaperasequencebasedcompensationstrategyhasbeendevelopedtocompensatebalancedorunbalancedincomingvoltagetoregulatetheloadvoltage.Theadvantageoftheschemeisthatunderallconditionsofunbalance,theDVRcontrollerisabletocompensatetheunbalance,evenifthevoltagecapabilityoftheDVRislimitedbyitsrating,whichmaybedecidedbysomeothergoverningfactorssuchascostoftheequipment,and/oroverallUPQCrating.Fig.1showstheschematicdiagramofaseriescompensatedsystemforloadvoltageregulation.TheDVRsystemconsistsofathree-phasevoltagesourceconverter(VSC),lowpassfilterandinjectiontransformer.TheDVRisdesignedsuchthatthemaximumbalancedvoltagesagcompensationisrestrictedto50%ofthesupplyvoltage.TheDVRiscontrolledfromaTMS320F2812TIfixedpointDSPcontroller.ThedetailedparametersofthetestsystemaredescribedinSectionIII.Fig.1.PowercircuitofDVRII.WORKINGPRINCIPLEANDCONTROLOFDVRA.WorkingPrincipleofDVRADVRmaintainstheloadvoltageatapredeterminedlevelduringanysourcevoltageabnormalconditionssuchasvoltagesag/swellordistortion.TheworkingprincipleoftheDVRcanbeexplainedwiththehelpofFig.2.ThreephasevoltagephasorsVa1,Vb1andVc1arebalancedwith100%magnitudeundernormaloperatingcondition.AfaultintheupstreamofthePCCcancauseabalancedorunbalancedvoltagedisturbanceatthePCCdependingonthetypeofthefault.Fig.2.VoltagePhasorDuringanunbalancedfaultsituation,thephasevoltagevectorsmaybealteredtoVa2,Vb2andVc2.Thesituationhereisthatofatypicallinetolinefaultwhichdoesnotinvolvegrounding.TheDVRcaninjectappropriatevoltagesVinja,VinjbandVinjcinordertobuildabalancedthreephasesystemofvoltagevectorsDifferenttypesofvoltagecompensationstrategyarediscussed2-8.In7anattempthasbeenmadetoreducethesystemlossesbykeepingtheexchangeofrealpowerbetweentheDClinkandsupplytoaminimum.Thisisachievedbyinjectingvoltagesinquadraturetothesupplycurrent.ThistypeofDVRdoesnotneedanyDClinksupportsincenorealpowerisinvolvedinvoltageinjection.Butduringdeepersags,ahighratingofinverterisnecessaryforcompensatoryaction.Thesequencecomponentbasedanalysiscarriedoutin8suggeststhatthemosteconomicalvoltageinjectioncanbeachievedbyre-aligningthevoltagevectorsaccordingtothepositivesequencecomponent.B.SequenceComponentControlofDVRAsequenceanalysisbasedcontrolstrategyisadoptedinthispaper.Thephasevoltagesareconvertedtobalancedsystemofpositive(V1),negative(V2),andzero(V0)sequencecomponents.TheDVRcontrolaimstomaintainthepositivesequencecomponentatapredeterminedvalueandtoreducethenegativesequenceandzerosequencecomponentstozero.Thezerosequencecomponentinthethreephasethreewiresystemconsideredhereiszero.Therefore,theinjectedvoltageVinjofaparticularphasecanbewrittenasthevectorsumofreferencevoltage(Vref),positive(V1)andnegative(V2)sequencevoltages,asgivenin(1).（1）12injrefVTheVinjaddstothesourcevoltagetoregulatetheloadvoltageatthedesiredlevel.ThevoltagethatcanbeinjectedbytheDVRinordertoestablishabalancedthree-phasesystemisdeterminedbytheratingofitsinverter.IfthedesiredmagnitudeofVinjisbeyondthecapacityoftheinverteroftheDVRlikeoneofthecasesconsideredinthispaper,ithastobelimitedtothemaximumvoltagecapacityoftheinverter.Incaseofabalancedvoltagesag/swell,thenegativesequencecomponentwillbezero.Therefore,onlypositivesequencein-phaseinjectionofthevoltageuptothemaximumcapacityoftheDVRwillmaintainthebalanceintheloadvoltagewithmaximumpossibleamplitude(Vmax).Butunderseverevoltageunbalanceconditions,limitingthemagnitudeofthecalculatedVinjwillnotensureabalancedvoltageconditionattheloadterminals.Therefore,itisnecessarytodeterminethemaximumamplitudeandangleofinjectionofthevoltagethatcanbeinjectedinordertoestablishasystemofbalancedthreephaseloadvoltageswithmaximumpossibleamplitude.DeterminationoftheappropriateVinj,underrestrictedinverterratingisthekeyresearchquestionofthispaper.Thevoltagetobeinjectedwhichisthecombinationofpositiveandnegativesequenceiscalculated.ThephasewhichrequiresmaximuminjectionisselectedandfollowingthreepossiblecasesofVinjaredefinedinthecontrol.（1）maxinjVWhencalculatedvoltagemagnitudeiswithinthecapabilityofthecompensator,nofurthercalculationisrequired.Thusinjectedvoltageisthecalculatedvoltage.（2）max2maxndinjVWhencalculatedvoltagemagnitudeishigherthanthemaximumpossiblevoltageandnegativesequencemagnitudeishigherthanthemaximumpossiblevoltage,maximumpossiblenegativesequencevoltageisinjected.（3）max2maxndinjVVWhencalculatedvoltagemagnitudeisgreaterthanVmaxbutnegativesequencemagnitudeislowerthanVmax,appropriatepositivesequencemagnitudehastobeselectedinordertokeeptheinjectedvoltagemagnitudeequaltothemaximumpossiblemagnitude.TheselectionofpositivesequencecomponentisexplainedwiththehelpofaphasordiagramshowninFig.3.OAisthevoltageofoneofthephaseswhichrequiresmaximumvoltageinjectionduringthefault.OGisthereferencevoltagesetalongthepositivesequencecomponentofthatphase.ThevoltageAGhastobeinjectedinordertoestablishthereferencevoltageinthisphase.AGisthecombinationofpositive(EG)andnegativesequence(AE)components.IncasethecompensatorisunabletoinjectAGandAF(Vmax)isthemaximumpossibleinjectiontoestablishabalancedvoltagecondition,thepositivesequencemagnitudehastobereducedtoEF.ThemagnitudeEFthatcanbeinjectedinthissituationcanbecalculatedfrom(2)-(5):(2)*sinGDA(3)2maxV(4)BE(5)CFABThereforeinjectedvoltageisrestrictedtocombinationofnegativesequencecomponentandreducedpositivesequencecomponentinallphasesinordertostaywithinthelimitofthecompensator.Fig.3.InjectedvoltagevectorcalculationIII.SIMULATIONANDEXPERIMENTALSETUPThepowercircuitoftheDVRisshowninFig.1.Itconsistsofathree-phasefullbridgevoltagesourceinverterbuiltwithIGBTswitches.Itisconnectedinserieswiththree-phase240Vpowersystemwith4kVA(130V:115V)single-phasetransformers.AserieslowpassLC(1.245mH,10Fperphase)filterisconnectedtoremovetheswitchingnoise.Theinverterhasa2200FDClinkcapacitor(operatingat230V,andpoweredbyadiodebridgerectifier).A2kVAR-Lloadisconnectedforalltests.ThevoltagesagprofilesarecreatedwiththehelpofCaliforniaInstrumentACsourceunit.AdetailsimulationmodelofthesystemisdevelopedinSimPowerSystemToolboxofMATLAB/Simulink.Theinverter,diodebridgerectifier,DClink,couplingtransformersandlow-passfiltersarerepresentedasintheactualexperimentalsetupinthediscretemodel.Sine-PWMswitchingpulsesaresuppliedtotheinverterat10kHzfrequency.ThecontroldevelopedinSectionIIisimplementedwithacontroloptimisedfixed-pointTIDSP(TMS320F2812).Afeed-forwardcontrolloopmeasuresthesourcevoltagecontinuouslyanditiscomparedwiththereferencevoltagetobemaintainedattheload.TheappropriatevoltagetobeinjectediscalculatedandswitchinginformationissenttotheIGBTswitches.Thein-builtPWMportsoftheDSPprovideswitchingpulsesat10kHzfrequency.ThecontrolblockisgiveninFig.4.Fig.4.ControlBlockofDVRThreephasevoltagesaresensedandconvertedtopositiveandnegativesequencein-phaseandquadraturecomponentsasshownin(6)(8).Themagnitudeandphaseangleofthepositiveandnegativesequencecomponentsarecalculated.TheappropriatevoltagetobeinjectediscalculatedasexplainedinsectionII.(6)sin()it-2/3)sin(t+2/3)23adpbqcVVt(7)si()it/)si(t-/)n+23n23adnbctVVThepositiveandnegativesequencecomponentswhicharetransformedtoDCin(6)and(7)areextractedwiththehelpofamovingaveragefilter(actsasalowpassfilter)overaperiodofonepowerfrequencycycleasshownin(8).(8),1TdqposnegdqpntVVt(9)22,posnegdposnegqposneg(10),1,ta()sdponegV(11)injrefposVTheslightvariationinthesystemfrequencyistakencarebyasoftwarephaselocking,inwhichtheinterruptgeneratingregisterperiodisadjustedaccordingtothezerocrossingofthesystemvoltagedetectedinthesoftware.IV.RESULTSA.SimulationResultsA30%balancedvoltagesagiscreatedat0.1secandclearedat0.3sec.140Vrmsisthereferencevoltageattheloadterminals.Theloadvoltageismaintainedat140VduringthesagperiodwiththehelpofDVR.Thesourcevoltage,loadvoltageandtheinjectedvoltageareshowninFig.5.Fig.5.Source,loadandinjectedvoltageduringabalancedsag(simulation)Fig.6showsthephaseAsource,loadandtheinjectedvoltages.Theinjectedvoltageisin-phasewiththesourcevoltage.TheDClinkissupportedbyadiodebridgerectifiertocarryoutappropriatein-phaseinjection.Fig.6.Aphasesource,loadandinjectedvoltage(simulation)Fig.7showsthesource,loadandinjectedvoltagewhenaunbalancedvoltagesagiscreated.Theappropriatevoltagesindifferentphasesareinjectedtobalancethesystemandmitigatethevoltagesag.Fig.7.Source,loadandinjectedvoltageduringaunbalancedsag(simulation)B.ExperimentalResultsThesourcevoltageisreducedto90Vrmsfrom140Vrmstocreateabalancedsagcondition.50VrmsisinjectedfromtheDVRtomaintaintheloadvoltageconstant.Thesource,injectedandloadvoltagescanbeseeninFig.8.Fig.8.Source,injectedandloadvoltageduringabalancedsag(experiment)Fig.9showstheloadvoltagetransientsduringvoltagesag.Itiscompensatedwithin3powercycleswhichcanbeobservedinFig.9.Fig.9.Loadvoltagetransientsduringvoltagesag(experiment)Thesource,injectedandloadvoltageduringanunbalancedsagisshowninFig.10.Thea,b,cvoltagesareasgivenaboveforthesimulation.V.CONCLUSIONSAsequencecomponentbasedcontrollerhasbeendevelopedforaDVR.Theperformanceofthecontrollerisverifiedbothinsimulationandexperimentation.ThecontrollerissimplebuteleganttoimplementwithaDSP.Experimentalresultsarefoundtobesatisfactorytovalidatetheproposedcontrolalgorithm.Theadvantageoftheschemeisthatunderallconditionsofunbalance/phasejump,theDVRcontrollerisabletocompensatetheunbalance,evenifthevoltagecapabilityoftheDVRislimitedbyitsrating,whichmaybedeterminedbysomeothergoverningfactorssuchascostoftheequipment.REFERENCES1A.GhoshandG.Ledwich,Powerqualityenhancementusingcustompowerdevices,Norwell,MA:Kluwer,2002.2J.G.Neilsen,M.Newman,H.NeilsenandF.Blaabjerg,“Controlandtestingofadynamicvoltagerestorer(DVR)atmediumvoltagelevel”,IEEETrans.PowerElectronics,vol.19,no.3,pp.806-813,May2004.3Z.Changjiangetal,“Dynamicvoltagerestorerbasedonvoltage-space-vectorPWMcontrol”,TransIEEEInd.Appln.,vol.37,Issue6,pp.1855-1863,Nov.-Dec.2001.4J.G.Neilsen,F.Blaabjerg,andN.Mohan,“Controlstrategiesfordynamicvoltagerestorercompensatingvoltagesagswithphasejump”,IEEEAppliedPowerElectronicsConferenceandExposition(APEC),Mar.2001,vol.2,pp.1267-1273.5M.I.Marei,E.F.El-saadanyandM.M.A.Salama,“AnewapproachtocontrolDVRbasedonsymmetricalcomponentsestimation”,IEEETransactionsonPowerDelivery,vol.22,no.4,pp.2017-2024,Oct.2007.6H-J.Jungetal,“AstudyonDVRcontrolonunbalancevoltagecom-pensation”,IEEEAppliedPowerElectronicsConferenceandExposition(APEC),Mar.2002,Vol.2,pp.1068-1073.7Y.Y.Kolhatkar,andS.P.Das,“ExperimentalinvestigationofasinglephaseUPQCwithminimumVAloading”,IEEETransac-tionsonPowerDelivery,vol.22,no.1,pp.373-380,Jan.2007.8S.Chen,G.Joos,“RatingissuesofUPQCforloadbusvoltagecontrolindistributionsystems”,IEEEPESWinterMeeting,vol.2.pp.944-949,2001.中文翻译基于DSP控制器的动态电压恢复器（DVR）序列分析JayantiN.G.,MalabikaBasu*,IurieAxente,KevinGaughanandMichaelF.ConlonSchoolofElectricalEngineeringSystemsDublinInstituteofTechnology摘要：文章探讨了动态电压恢复器（DVR）在电压平衡或者电源电压骤降的不平衡条件下的表现，并限制DVR注入能力（如限制电源电压注入到50）。电源电压的序列成分被提取出来产生DVR的注入参考电压。控制器确定在补偿的能力范围内的可能注入的最大正序电压，以平衡负载端电压。控制器是经过模拟和实验验证的。控制算法已经在TI320F2812定点DSP实现，在三相10kVADVR的实验室中验证了该控制器的有效性。在三相240V系统中，建立了平衡凹陷和幅度和相位不平衡的凹陷，利用DVR和推荐的控制器成功的进行了补偿。1引言动态电压恢复器（DVR）为电压敏感的客户提供抵抗来自传入的传输/配送系统电压干扰的动态保护。DVR也形成统一电能质量调节器的串联补偿器（UPQC）实现上述目的1。通常情况下，DVR/UPQC安装在敏感的电压服务区接入点，以补偿电压扰动，如凹陷/膨胀或不平衡，这样整个关键负载端电压调节是完全受控制的3-6。本文确定了以序列为基础的补偿策略，以补偿平衡或不平衡的输入电压，调节负载电压。该设计的优势是在所有不平衡的情况下，DVR的控制器能够补偿这种不平衡，即使DVR的补偿电压能力受限于其额定值，这可能是由其他一些因素，如设备成本，和/或超过所有UPQC额定值。图1显示了调节负载电压的串联补偿系统示意图。DVR系统由三相电压源转换器（VSC），低通滤波器和注入变压器。DVR的设计时最大补偿的平衡电压骤降仅限于电源电压的50。利用TMS320F2812的TI定点DSP控制器控制DVR。测试系统的详细参数将在第三节介绍。图1DVR电路2DVR工作原理及控制A.DVR的工作原理DVR在任何电源电压异常情况，如电压骤降/骤升或失真，可以将负载电压保持在预定的水平。DVR的工作原理可以利用图2进行解释。三相电压相量VA1，VB1和VC1正常运行的情况下平衡并且幅度为100。在PPC的上方出现故障，根据故障类型可能会导致PPC的平衡或不平衡电压扰动。图2电压相量图在不平衡故障的情况下，相电压向量VA2，VB2和VC2可能会改变。这里的情况是一个典型且不涉及地线的线路故障。DVR可以注入适当的电压Vinja，Vinjb和Vinjc，以建立一个平衡的三个相电压矢量系统，2-8中讨论了不同类型的电压补偿策略。7中尝试通过保持和直流母线之间实际功率的交换，并且提供一个最小值，以减少系统的损失。这是通过注入正交的电压来提供电流。这种类型的DVR不需要任何直流环节的支持，因为没有真正的电源注入电压。但在更深的电压跌落，一个高品质的逆变器是必须作出补偿动作。8中进行的基于序分量的分析表明，最经济的注入电压方式可以通过按正序分量重新调整电压矢量来实现。B.DVR的序列分量控制本文提出了一个基于序列分析的控制策略。相电压转换为正序分量（V1），负序分量（V2）和零序分量（V0标准）的平衡系统。DVR控制的目标是将正序分量维持在预定值，并将负序和零序分量减少到零。在三相三线系统的零序分量视为为零。因此，一个特定阶段的注入的电压Vinj可以写成矢量和参考电压（VREF），正序分量（V1）和负序分量（V2）的序列电压，如（1）。（1）12injrefVVinj添加到电源电压中以将负载电压调节到所期望的等级。可以通过DVR注入电压，以建立一个平衡的三相系统，这取决于变频器的等级。如果所需注入的Vinj幅度超出DVR逆变器能力，就像本文所考虑的情况之一，必须对逆变器的输出能力进行限制。在一个平衡的电压骤降/骤升的情况下，负序分量将为零。因此，只有正序分量注入一相的电压达到DVR最大能力时，DVR将利用最大可能的幅值（VMAX）来保持负载侧电压的平衡。但是，在电压严重不平衡的条件下，限制计算出的Vinj的幅度不会确保在负载端电压在平衡条件下。因此，确定可以注入电压的最大幅值和相位角，以建立一个最大可能幅度平衡的三相负载电压系统。本文重点研究的问题是根据变频器等级测定适当的Vinj限制电压。计算出被注入的正序和负序结合的电压。选择最大注入的阶段，在控制中需要选择以下三种可能的情况定义Vinj。（1）maxinjV当计算出的电压幅值在补偿能力之内，不需要进一步的计算。此时注入的电压即为计算电压。（2）max2maxndinjV当计算出的电压幅度高于最大可能电压，并且负序电压幅度高于最大可能电压高，此时注入最大的负序电压。（3）max2maxndinjV当计算出的电压幅度比的Vmax大，但负序电压幅度低于的Vmax，为了保持注入的电压幅值与可能出现的最大幅值相等，选择适当的正序电压幅值。图3中的相量图解释了选择正序电压分量的原因。OA是在一个故障阶段，需要注入的最大电压。OG是沿着这一阶段的正序分量设定的参考电压。AG注入电压，以建立在这一阶段的参考电压。AG是正序分量（EG）和负序分量（AE）的组合。补偿的情况下是无法注入AG的，AF（VMAX）是建立一个平衡的电压条件下最大可能的注入的电压，正序分量的幅值将减少到EF。在这种情况下EF可以注入的幅值可以由（2）-（5）计算出：(2)*sinGDA(3)2maxAGVD(4)BE(5)CFAB因此注入的电压受限于负序分量和在各个阶段减少的正序分量，这样就可以保证在补偿限制以内。图3注入电压相量计算3仿真和实验步骤DVR的电路如图1所示。它包含由IGBT开关组成的三相全桥电压源逆变器。它连接在三相240V、单相变压器4kVA（130V：115V）的电力系统中。连接一系列低通LC（1.245mH，每相10F）过滤器，以消除开关噪声。变频器有一个2200F的直流电容器（工作在230伏，由一个二极管桥式整流供电）。连接2千伏安的R-L负载用作所有的测试。电压骤降的状况是在加州仪器交流电源装置的帮助下创建的。利用MATLAB/Simulink中SimPowerSystem的工具箱建立一个详细的仿真模型系统。在离散模型中，逆变器，二极管整流桥，直流电容器，变压器耦合和低通滤波器代替在实际的中的实验装置。提供给逆变器的正弦PWM开关脉冲设定在10kHz频率。在第二节提出的控制策略是由优化定点的TIDSP（TMS320F2812）来实现。前馈控制回路连续的测量电源电压，并且与保持负载电压稳定的参考电压相比较。计算出需要注入适当的电压值，并且开关信号发送到IGBT开关器件中。DSP内置的PWM模块发出10kHz频率的开关信号。图4给出了控制框图。图4DVR控制框图（6）-（8）表示了检测的三相电压，并且转换为正序分量，负序分量和正交分量。计算的正序分量，负序分量的幅值和相角。根据第二节解释计算出被注入合适的电压。(6)sin()it-2/3)sin(t+2/3)23adpbqcVVt(7)si()it/)si(t-/)n+23n23adnbctVV（8）显示了超过一个工频周期内，在移动平均滤波器作用下，（6）（7）将正序分量和负序分量转换为直流电压。(8),1TdqposnegdqpntVVt(9)22,posnegdposnegqposneg(10),1,ta()sdponegV(11)injrefposV在系统频率略有变化时，采取软件锁相，在这期间产生的中断寄存器是根据软件检测系统的电压过零点来调整的。4结论A.模拟结果在0.1秒建立平衡电压骤降30，在0.3秒时清除。140VRMS是负载端的基准电压。在电压跌落期间，负载电压在DVR的帮助下保持在140V。源电压，负载电压和注入电压的波形如图5所示。图5在电压平衡跌落期间电源电压、负载电压、注入电压波形图（仿真）图6显示了A相的电压，负载和注入电压。注入电压相位与