Chapter8

ControlMethodsandTheirImplementationofVehicleDriveMotors車用驅(qū)動電機原理與控制基礎(chǔ)(第2版)PrincipleandControlFundamentalsofVehicleDriveMotors28.1PrincipleofField-OrientedControl(FOC)Thefour-coilprototypemotoroffersmorecontrolfreedom.Takingstatorcontrolasanexample,thebasicvectorcontrolarchitectureofthefour-coilprototypemotorisshowninFig.8-1.Thiscontrolstructureisbasedonthespacevectorform.Fig.8-1Basicvectorcontrolarchitectureofthefour-coilprototypemotor

38.1PrincipleofField-OrientedControl(FOC)

Fig.8-2FOCstructureofthePMSM48.1PrincipleofField-OrientedControl(FOC)IncontrasttoPMSM,thegenerationoftherotormagneticfluxininductionmotorsarisesfromtheexcitationofthestatorcurrent.Therefore,unlikePMSM,inrotormagneticfieldorientationvectorcontrol,thedirectionoftherotormagneticfieldcannotbedetectedsimplybysensingthemechanicalpositionoftherotor.Itrequiresanalysisandestimationoftherotormagneticfluxbasedonsignalssuchasstatorcurrent,rotorspeed,andstatorvoltage.Theestimationmethodforrotormagneticfluxcanbereferredtothevoltage-currentmodeorcurrent-speedmodelintroducedinSection8.6.OtherissuesregardingFOCininductionmotorareessentiallysimilartothoseinPMSM.Fig.8-3FOCstructureoftheinductionmotor5Three-PhaseACPower

68.2PulseWidthModulation(PWM)InverterandSpaceVectorModulation8.2.1BasicStatorVoltageVector

Fig.8-4StatorVoltageVector-WindingsarepoweredbytheinverterItisdefinedthatwhentheuppertubeofabridgearmisinthe“on”state,theswitchstateofthebridgearmis“1”;whenthelowertubeofthebridgearmis“on”,theswitchstateis“0”.Inthisway,thethreebridgearmstatecombinationshaveatotalofeightstatesof000,001,010,011,100,101,110,and111,whicharecalledeight“basicvoltagespacevectors”(referredtoas“voltagebasisvectors”).Amongthem,000and111maketheinverteroutputvoltagezero,sothesetwoswitchingmodesarecalledzerostates.78.2.1BasicStatorVoltageVector

Fig.8-5Statorvoltagevector(100vector)88.2.1BasicStatorVoltageVector

Fig.8-6Thebasicvoltagespacevectors98.2.2Volt-SecondEquivalencePrincipleandSVPWMFig.8-7SynthesisofSpaceVoltageVectors

10SVPWMVoltageVectorInscribedCircle內(nèi)切矢量圓

118.2.2Volt-SecondEquivalencePrincipleandSVPWM

Fig.8-8basicvoltagespacevectors128.2.2Volt-SecondEquivalencePrincipleandSVPWM

Fig.8-9StatorreferencevoltagevectorsynthesisInthesecondstep,afterthesectorisdetermined,thevoltagecommandissynthesizedfromthenon-zerovoltagebasevectorandzerovoltagevectorthatcomposethesector.138.2.2Volt-SecondEquivalencePrincipleandSVPWMFig.8-10Thefirstsectorvoltagecommandthree-phasePWMwaveform

14AVideotoIllustrateGenerationProcessofSVPWM15

Commonemitterconnectionandvolt-amperecharacteristicsofNPNtransistors

8.4PowerSemiconductorDevices-GTR16

FieldEffectTransistor(FET)isadevicethatcontrolstheconductivityofasemiconductorbychangingtheelectricfieldthroughthechannel.Thecurrentpassingthroughitchangeswiththestrengthoftheelectricfield.Ithastwotypes:junctiontypeandsurfacetype.TheformerisbasedonthePNjunction,andthelattercontrolsthecurrentinthechannelwiththesurfaceelectricfield.

Theelectricfieldoftheinsulatinglayeriscontrolledbyanappliedvoltagetochangethesurfacefieldeffectofthechannelconductanceinthesemiconductor,soitisalsocalledaninsulatedgatefieldeffecttransistor.

Dependingonthematerialusedfortheinsulatinglayer,therearevarioustypesofIGFETs.

Atpresent,themostwidelyusedmetal-oxide-semiconductorfieldeffecttransistor(MOSFET)orMOStubeforshort.SchematicdiagramofpowerMOSFETunitstructureElectricalgraphicsymbolsforMOSFETs8.4PowerSemiconductorDevices-MOSFET178.4PowerSemiconductorDevices-MOSFET

Commonemittercircuit,outputcharacteristicsandtransfercharacteristicsofn-channelenhancement-modeP-MOSFETa)b)c)18

Commonemittercircuit,outputcharacteristicsandtransfercharacteristicsofn-channelenhancement-modeP-MOSFET8.4PowerSemiconductorDevices-MOSFET198.4PowerSemiconductorDevices-MOSFET

208.4PowerSemiconductorDevices-IGBTSchematicdiagram,symbolandequivalentcircuitofIGBT

218.4PowerSemiconductorDevices-IGBTThevolt-amperecharacteristicsandshort-circuitcharacteristicsofIGBTs

228.4PowerSemiconductorDevicesThedevelopmentofsemiconductormaterialscanbedividedintothefollowingstages:1)SiandGerepresentthefirstgenerationofsemiconductormaterials.2)GaAs(galliumarsenide),AlAs,andsimilarmaterialsdevelopedinthe1960sareconsideredthesecondgenerationofsemiconductormaterials.3)Inthepasttwodecades,thethirdgenerationofwidebandgapsemiconductormaterials,primarilySiCandGaN,hasgraduallyemerged.Thebandgapwidthofsiliconcarbide(SiC)isaboutthreetimesthatofsilicon(Si)material,givingSiCsignificantadvantagesoverSiintermsofvoltageresistanceandhigh-temperaturetolerance.Additionally,SiCdevicesexhibitmuchlowerleakagecurrentscomparedtoSidevices.Consequently,SiCdevicescanoperateinharshenvironmentssuchashightemperaturesandhighradiation.Table8-4PhysicalPropertiesofMajorPowerSemiconductorMaterials238.5IntegratedTechnologiesforAutomotiveMotorControllersThecompositionofthevehiclemotorcontrollerincludeshardwareandsoftware.Thehardwaremainlyincludesthemainpartssuchaspowercircuit,controlcircuitandstructuralheatdissipation.Thehardwaremainlyincludesthemainpartssuchaspowercircuit,controlcircuitandstructuralheatdissipation.

ThesoftwareincludesthesoftwareofthecontrolcircuitMCUandthesoftwareoftheprogrammablelogicdeviceintheprotectioncircuit.

Thepowercircuitmainlyincludespowermodules,capacitors,powerbusbars,etc.Exampleofcompositionofvehiclemotorcontroller24Audi-EtronMotorController25Thedemandcharacteristicsforautomotivepowermodulescanbesummarizedasfollows:1)WideTemperatureCharacteristics:Oneofthemostimportantandchallengingtechnicalrequirementsforpowermodulesinautomotiveapplicationsistheabilitytooperatenormallyatambienttemperaturesupto105°Cwithoutdegradingperformanceorreducingthelifespanofthemodule.2)ComplexOperatingConditions:Unlikeindustrialapplicationsinvolvingmotordrives,theoperatingconditionsforelectricvehiclesaremorecomplex.Forexample,inurbandrivingconditions,thevehiclefrequentlytransitionsbetweenacceleration,deceleration,andcruisingstates.3)HighReliabilityRequirements:Automotivepowermodulesmustmatchthelifespanofthevehicle,placinghigherdemandsonthedurabilityoftheIGBT.Typically,theoperationallifespanofapowermoduleis15yearsormore.Themainfactorsinfluencingpowermodulefailureincludepowercycling,thermalcycling,andvibration.Theselectionofpowermodulesforautomotiveelectricdrivesystemsmainlyconsidersthefollowingaspects:1)RatedVoltageandRatedCurrent:FormostA0-classandhighernewenergyvehicles,exceptforthosewithminimalhybridization,theratedvoltageofthepowerbatterypackisgenerallyaround300V.Duringbrakingorcharging,thebatteryvoltagemayriseabove400V.2)SwitchingFrequencyandSwitchingLoss:Increasingtheswitchingfrequencycanimprovethepowerdensityofthemotorcontroller,reducethesizeofthefilter,andminimizeoreliminatethesnubbercircuit,therebyreducingtheoverallsizeandweightofthecontroller.Additionally,itcangenerateelectromagneticinterference(EMC)noise.3)DynamicCharacteristicsandDeviceProtection:Theswitchingdevicesshouldbecapableofwithstandinghighvoltage/currentchangerates.Thedrivingpowerofthedeviceshouldbeverysmall,whichrequiresthedevicetohaveaverylowinputcapacitanceandveryhighinputimpedance(severalMΩormore).4)Cost:Thepriceofpowermodulescanaccountfor30-40%ofthetotalcostoftheinverter.Therefore,itisessentialtochoosedeviceswithahighperformance-to-priceratiowheneverpossible.8.5IntegratedTechnologiesforAutomotiveMotorControllers26DrivingCircuit27TheFunctionsofDrivingCircuitThefunctionsofdrivingcircuit:poweramplification,isolation,andwaveformadjustment288.5IntegratedTechnologiesforAutomotiveMotorControllersSchematicdiagramofatypicalelectricalisolationmethodTheIGBTdrivecircuitistheinterfacebetweenthelow-voltagecontrolcircuitandthehigh-voltagemaincircuit,andmainlyplaystheroleofdrivingpoweramplificationandprotectingpowerdevices.IthasanimportantinfluenceontheswitchingcharacteristicsoftheIGBT,includingswitchingspeed,switchinglosses,peaksandoscillationsofthewaveform,etc.Thedrivecircuitisanimportantlinkconnectingthecontrolcircuitandthepowercircuit,andshouldplaytheroleofhighandlowvoltageelectricalisolation.Atpresent,mainstreamdrivecircuitscanbedividedintothreecategoriesaccordingtoisolationmethods:opticalisolation,magneticisolation,andcapacitiveisolation.1）

Optocouplerisolationdriver：Theopto-isolateddriverusuallyusesanoptocouplertoachieveelectricalisolation.Sincetheoptocouplerisolationcanonlytransmitsignalsinonedirection,thehigh-frequencyinterferencesignalonthesecondarysidewillnotaffecttheprimaryside,soithastheadvantagesofstronganti-interferenceabilityandstableoperation.

2）

Magneticallyisolateddrive：Themagneticisolationdriveadoptstheisolationmethodofthepulsetransformer,andthesignalandenergyaretransmittedthroughthemagneticfield.

3）

Capacitiveisolateddrive：Capacitiveisolationdrivesusecapacitorsforisolationanduseelectricfieldstotransmitsignals.。298.5IntegratedTechnologiesforAutomotiveMotorControllersThecommonlyusedautomotivefiltercapacitorsaremainlydividedintotwocategories:electrolyticcapacitorsandfilmcapacitors.Tofurtherreducethesizeandweightofinvertersandmeettherequirementsofwidevoltagerangeandhigh-powerapplications,acompact,low-loss,cost-effectiveDC-Linkcapacitorisneeded.Comparedtoelectrolyticcapacitors,filmcapacitorshavethefollowingadvantages:ExcellentTemperatureCharacteristics:DC-Linkfilmcapacitorsusehigh-temperaturepolypropylenefilm,offeringgoodtemperaturestability.Incontrast,thecapacitanceofelectrolyticcapacitorsdropssharplyatlowtemperatures,affectingtheirapplicationincoldenvironments.AbilitytoWithstandReverseVoltage:Ifareversevoltageexceedingthespecifiedvalueisappliedtoanelectrolyticcapacitor,achemicalreactionoccursinsidethecapacitor,potentiallycausinganexplosionorelectrolyteleakageasinternalpressureisreleased.Filmcapacitors,beingnon-polar,canwithstandbidirectionalvoltagesurges,offeringhigherreliability.StrongPulseVoltageResistance:Filmcapacitorshavebetterimpactvoltageresistancecomparedtoelectrolyticcapacitors.DryDesign,NoElectrolyteLeakage:Filmcapacitorsdonothaveissueswithelectrolyteleakageandacidpollution.LowESRandHighRippleCurrentCapability:Filmcapacitorstypicallyhavelowerequivalentseriesresistance(ESR),witharipplecurrentcapabilityofupto200mA/pF.Incontrast,electrolyticcapacitorshavemuchlowerripplecurrentcapability.LowESL:Thelowinductancedesignofinvertersrequiresthemaincomponent,theDC-Linkcapacitor,tohaveextremelylowequivalentseriesinductance(ESL).High-performanceDC-Linkfilmcapacitorsintegratethebusbarintothecapacitormodule,reducingself-inductanceandminimizingoscillationeffectsatoperatingswitchingfrequencies.LongServiceLife:Filmcapacitorshavealongerservicelifeunderratedvoltageandratedoperatingtemperatureconditions.308.5IntegratedTechnologiesforAutomotiveMotorControllers

MotorControllerCoolingSystemThermalResistanceCircuitEquivalentThevehiclemotorcontrollerismainlyliquid-cooled,andtheheatingelementiscooledmainlybyconductionheatdissipation.

Thepowermoduleofthevehiclemotorcontrolleradoptsacompactarrangement,andthepowermodulecanbeapproximatelyconsideredasasingleheatsource;atthesametime,thecoolingsystemadoptsanoptimizeddesignscheme,sothattheheatofthecoolingsystemcanbedissipatedintime,soitcanbeconsideredasaradiatorforthemotorcontroller.31

Halltypecurrentdetectionprinciple8.5IntegratedTechnologiesforAutomotiveMotorControllers328.5IntegratedTechnologiesforAutomotiveMotorControllers

Fig.8-26CurrentDetectionPrincipleBasedonSamplingResistor338.5IntegratedTechnologiesforAutomotiveMotorControllersSchematicdiagramofMCUworkingmodeconversionThefollowingexamplesillustratetypicalsoftwarefunctionmodules.（1）

MotorControlStateMachineDesign.

Theintroductionofstatemachine(StateMachine)isverynecessaryforconcurrenttaskapplications.Itcanensurethattheembeddedcontrollermakesareasonable/timelyresponsetoexternalinputbydividingdifferentworkingmodes.

Thestateofthemotorcanbedividedinto:Initialization、Standby、HVActive、SpdqCtl、TrqCtl、DisCharge、Failure.（2）

Motortorquecontrolfunction.

TorquecontrolmeansthattheMCUreceivesthetorquecontrolrequestsentbythehostcomputer,andoutputsthetorquethatmatchestheworkingconditionswhileconsideringtheworkingconditionsofthemotorsystem(voltage,speed,temperature).Thetorquecontrolandfunctionrealizationofthedrivemotormainlyincludethemaximumtorquetocurrentratio(MTPA)controlinthelow-speedconstanttorquecontrolarea,theconstantpowerfieldweakeningcontrolinthehigh-speedarea,thespeedcontrol,andthevoltagecontrol.（3）

Communicationmodulesandotherfunctions.

TheelectronicstructureofmodernautomobilesismainlytoconnectdifferentECUsthroughtheCANbuscommunicationsystemtoformadistributedcontrolsystem.34PMSM

V.S.InductionMotorPMSM

orientationInductionMotororientation

SelectingthearbitrarymagneticfieldsynchronousMTcoordinatesystemtotherotorDQcoordinatesystem.

358.6RotorMagneticFieldPositionMeasurementandEstimationforACMotors8.6.1TypicalMotorPositionandSpeedMeasurementSensors

Resolverinstallationandstatorwindingstructurediagram,resolverexcitationsignalandsineandcosinereturnsignal368.6.1TypicalMotorPositionandSpeedMeasurementSensors

PrincipleofResolverDecodingPhaseLockedLoopMethod378.6.1TypicalMotorPositionandSpeedMeasurementSensorsTheworkingprincipleofaHalleffectspeedsensorisillustratedinFigure8-31,basedontheHalleffectprinciple.Ametalorsemiconductorthinfilmisplacedinamagneticfieldalongthez-axis.Whencurrentflowsinthex-direction,anelectromotiveforceisgeneratedperpendiculartoboththecurrentandthemagneticfield(inthey-direction).TheessenceoftheHalleffectisthatthemovingchargecarriersinthex-directionaresubjectedtotheLorentzfor