《车用驱动电机原理与控制基础 第2版》 课件英文 Chapter 3 Electromechanical Energy Conversion

Chapter3

ElectromechanicalEnergyConversionandElectromagneticTorqueGeneration车用驱动电机原理与控制基础(第2版)PrincipleandControlFundamentalsofVehicleDriveMotors23.1ElectromagneticSystem/LinearMotorModelwithMechanicalPortsFig.2-6Freechargeinamagneticfield

3Fig.3-1Theforcesituationofanenergizedconductorinthemagneticfield

3.1ElectromagneticSystem/LinearMotorModelwithMechanicalPorts4Fig.3-2Motionsynthesisoftheelectricchargesintheenergizedconductorandforcesynthesisinthemagneticfield

3.1ElectromagneticSystem/LinearMotorModelwithMechanicalPorts5Theelectromechanicalenergyconversionofoperationprocessforthemotorismuchmorecomplicatedthanthislinearmotor.However,theelectromechanicalenergyconversionprocesshasthefollowingbasiccharacteristics:1)Lorentzforceisthemicrophysicalbasisoftheelectromechanicalenergyconversion;2)Magneticfieldisanimportantmediatorintheelectromechanicalenergyconversion,butmagneticenergydoesnotnecessarilyincreaseordecrease;3)Theelectromechanicalenergyconversionmusthavetwoenergycouplingports:mechanicalportandelectricalport.Thereshouldbe“potentialquantities”actingontheports:themechanicalportisforceortorque,andtheelectricalportiselectricpotentialorelectricfield；4)Theinducedelectromotiveforceisanecessaryconditionforobtainingorreturningelectricalenergyfromelectricalports.Notethatinthiscase,itisassumedthatthemagneticfieldisconstantandtheinfluenceofthemagneticfieldaroundtheenergizedconductorisignored.Thiscasedoesnotreflecttheactualoperatingconditionsofthemotor.Inreality,thereisanarmaturereactionprocessinthemotor,wheretheairgapmagneticfieldisthecompositemagneticfieldofthearmaturefieldandtherotorfield.3.1ElectromagneticSystem/LinearMotorModelwithMechanicalPorts63.2EnergyStorageintheElectromagneticSystem:MagneticEnergyandMagneticCoenergy

Fig.3-3Separatingthelossesmakesthesystema“magneticenergystoragesystemwithoutlosses”Port

MechanicallossLosslessMagneticEnergyStorageSystem73.2.2MagneticEnergyandMagneticCoenergyFig.3-4Ironcorewithdoublecoilexcitation

83.2.2MagneticEnergyandMagneticCoenergy

93.2.2MagneticEnergyandMagneticCoenergy

Fig.3-6Integrationpathofmagneticenergy103.2.2MagneticEnergyandMagneticCoenergy

113.3GenerationandUnifiedExpressionofElectromagneticTorque

Fig.3-7Electromechanicaldeviceswithstatorandrotorwindingsandairgaps123.3GenerationandUnifiedExpressionofElectromagneticTorque

133.3GenerationandUnifiedExpressionofElectromagneticTorque

143.3GenerationandUnifiedExpressionofElectromagneticTorque

Fig.3-8GenerationofreluctancetorqueFig.3-9Variationcurveofstatorwindingself-inductance153.3GenerationandUnifiedExpressionofElectromagneticTorqueFig.3-9Reluctancetorquevarieswithrotorposition

Fig.3-8Generationofreluctancetorque

16Faraday‘sLawofElectromagneticInduction(fromMagnetic

→

Electricity)Faraday'sLawofElectromagneticInduction:Thephenomenonofelectromagneticinductionreferstothegenerationofaninducedelectromotiveforce(EMF)duetothechangeofmagneticflux.ThedirectionoftheinducedemfinFaraday'sLawofElectromagneticInductioncanbedeterminedbyLenz'sLaw:Theinducedcurrent'smagneticfieldopposesthechangeintheoriginalmagneticflux.

Mechanicalsystem(singlemass)

ElectromagneticsystemNewton'sFirstandSecondLawsofMotion:Newton'sFirstLawofMotion,alsoknownastheLawofInertia.Itisstatedasfollows:Anobjectwillremaininmotionoratrest,unlessacteduponbyanexternalforce.Newton'sSecondLawofMotion:Theaccelerationofanobjectisdirectlyproportionaltothenetforceactingonit,isinthesamedirectionasthenetforce,andisinverselyproportionaltotheobject'smass.ForceisthecauseofchangesinmotionVoltageandthechangeoffluxlinkagearemutuallycausal17ThePrincipleofElectromechanicalEnergyConversionofMotorsMaxwellappliedtheLagrangianmethodtodescribethedynamicsofelectromechanicalcoupledsystems.Hederivedthesystem'sequationsofmotionfromthefundamentallawsofmechanicsandelectromagnetics,resultinginthe“Lagrangian-Maxwellequations”.

Lagrangian-Maxwellequations:Mechanicalsystem(singlemass)Electromagneticsystem18

Fig.3-12electromagnet3.4TheDefinationofSpaceVector19

3.4TheDefinationofSpaceVector20Fig.4-11a)Themagneticfieldgeneratedbythefullpitchcoil

TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings21Fig4-11b)Thewavefunctionofmagnetomotiveforceforfullpitchcoil

TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings22

TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings23

TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings24Fig.4-16Three-phasefundamentalwavesatdifferenttimesFig.4-17rotatingmagnetomotiveforcewave

TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings25Fig.4-18Thespacecomplexplanecorrespondingtotheaxialcross-sectionofthemotor

TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings26TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings

27Fig.4-21Thecurrentvectorsofstatorandrotorareequivalenttothe"axiscoil“currentvectors

TheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWindings28Fig.4-20Thestatormagnetomotiveforcevectoranditsmovingtrajectory

Fig.4-22Thecosine-distributedmagneticfieldgeneratedbytheA-phasewindinga)Cosine-distributedMMFwaveb)Expandingofcosine-distributedmagneticfieldTheCompositeFluxLinkageWaveofOrthogonalTwo-phaseWinding293.5VectorExpressionofElectromagneticTorqueFig.4-27Synthesisofstatorandrotormagnetomotiveforcespacevector

30Fig.4-27Synthesisofstatorandrotormagnetomotiveforcespacevector

3.5VectorExpressionofElectromagneticTorque31ElectromagneticLoadofMotors

32ElectromagneticLoadGiventhevolumeofthemotor,theelectromagneticloaddeterminesthemotor'soutputtorquecapability.Inotherwords,foradesiredoutputtorque,thelargertheelectromagneticload,thesmallerthemotorvolume.Increasingtorqueoutputcapabilitymainlydependsonthemagneticloadandelectricalload.Increasingtheelectromagneticloadisbeneficialforachievingtheminiaturizationandlightweightofthemotor.Theselectionofelectromagneticloadma