Efficiency Improvement coupling Multi-Speed - Tesionline：效率的提高耦合的多速tesionline

EfficiencyImprovementcouplingMulti-SpeedTransmissionstoTractionDrives

MarcoSantoro

Abstract

UsingsimulationmodelsdevelopedinaMATLAB®-Simulink®environment,thecontinuousbehaviourofavehicleisapproximatedasaseriesofdiscretesteps.Duringeachstepthecomponentsareassumedtobeatsteadystate,andthisassumptionallowstheuseofpower-usageorefficiencymapsforthecomponents,whicharederivedfromsteady-statetestsinthelaboratory.Inthisway,bymodifyingthedefaultlayoutofADVISOR©(ADvancedVehIcleSimulatOR),ananalysistoolforusewithMATLABandSimulink,isshownthatbycouplingmulti-speedtransmissionswithtractiondrivesinelectricandhybridvehicles,betterenergy-conversionefficienciesmaybegained.

Keywords:electricdrive,efficiency,energy,simulation,transmission.

1 Figuresofmeritoftractiondrivesforvehicularapplications

Thecomparisonoftractiondrivesforvehicularapplicationsbasedontheirtechnicaldataisacomplexchallenge.Theenergystoragesystem'snominalvoltagerequiredbymostofthetractiondrivesonthemarketvariesbetweenUbatt=90VandUbatt=600V,themaximumspeedofthedrivesiscomprisedbetweenmax=4,000rpmandmax=10,000rpm,themaximumtorquebetweenTmax=90NmandTmax=400Nm.Severaldrivesareliquid-cooled,someothersareair-cooledandothersareoil-cooled.

Criteriatocomparesuchdifferentdrivetechnologieshavetobebasedonmeaningfulvariablesmeasurableontestbenches[1;2;3;4]oravailableindatasheets.

Themaximumpower(Pmax)ofadriveisoftentheonlycriteriaconsidered.NonethelessPmaxislimitedbythemaximumallowablecurrentfrombatteries-whichissometimesatrade-offbetweenthedesiretogetthehighestpossiblepowerfromthedriveandtheneedtoguaranteealonglifetothebatteries-andthemaximumallowablecurrentflowinginthepowersemiconductorsintheinverter.Themotoritselfhasnodirectpowerlimits:itsperformanceislimitedbythewindings'insulationtemperature.Fromthispointofviewthemotorcanbethoughtasanaccumulatorofthermalenergyinwhichthelossesofthemotorarestored.Thermalenergyiscontinuouslydissipatedovertheoutputshaft,themotor'ssurfaceandthecoolant.Partofmotor'spowerloss(Ploss)notremovedbythecoolantcausesthemotortoheat:theresultingwindings'temperaturedependsthusontheloadserviceofthemotor.Aparameterrepresentingthisbehaviouristhecontinuouspower(Pcont),definedasthepowerthedrivecancontinuouslyprovidewithoutoverheating:Pcontisreachedwhenthemotor'spowerlossisjustlikethemaximumpowerofthecoolingsystem.Fromthispointofview,themoreinherentlyefficientamotoris,thegreaterthetorqueis,atwhichthemaximumallowablewinding'stemperatureisreached.

Themaximumpowerofatractiondriveisthusacriteriaforsizingtheinverterandthebatterieswhilethecontinuouspowerdependsonthemotor'stechnologyandthecoolingsystem.Somedrivescandevelopthemaximumpoweronlyforshortperiodsutilisingtheirthermalcapability:theycanbeoverloaded.Otherdrivescanfurnishtheirmaximumpowerforonehouratleast:theycannotbeoverloadedandtheirmaximumpowercoincidestothecontinuouspower.

Anothercomparingcriteriaistheoverloadcapability-orbetterovertorquefactor,asPmaxisfurnishedwhentheoutputtorqueexceedsforshortperiodsthemaximumcontinuoustorque-,definedastheratiobetweenthemaximumpowerandthecontinuouspower(Eq.1).

(1)

Ahighovertorquefactorisadvantageousduringpassingmaneuver,rapidaccelerationsandstartingongrades.

Inordertocomparedifferenttractiondrivesoftenaredefinedparametersrelatingthecontinuouspowertothedrive'smassandvolume:thecontinuouspowertoweightratio-thespecificpower-andthecontinuouspowertovolumeratio(Eq.2).Thedrive'smassentailsthemassesofmotor,inverterandconnectingcables.

(2)

Agoodpowerperformanceisrequiredwhileclimbing,duringaccelerationsanddrivingathighspeeds."Aggressive"accelerationsusuallyneedhighwheel-torquevaluesatmoderatespeedsforshorttimeswhilehighway-cruisingrunsrequirehightractionpowersforlongtimes.Themaximumavailabletorquetothewheels(Eq.3)whenthevehicleisstartingistheproductofthedrive'smaximumtorque(Tmax)tothelowestgearratio(1).

(3)

(4)

Theclimbingability(Eq.5)canberepresentedbytheproductofthedrive'smaximumtorquetothedrive'smaximumspeed[5].

(5)

PclimbismuchgreaterthanPmaxandcannotactuallybegenerated,butifitisdividedbythemaximumwheelspeedwhichcanbereachedoveragearratio,Pclimbrepresentsthemaximumwheeltorqueavailablewiththegearratio-whendividedbythemaximumwheeltorqueavailablewithagearratio,isthemaximumwheelspeedcanbereachedwiththatgearratio(Eq.6,forthe1stgearratio).

(6)

Inordertoestimatethequalityofdrives,onemustsometimesrefertotheefficiency(Eq.7)ofthedriveinoneoperatingpoint.Thisisagoodparameterformotorsinsteadyoperationinornearaparticularoperatingpoint.Forexamplelookingatadrive'sfrequencydistributionD(,T)ofoperatingpoints(figure1)duringadrivingscheduleliketheNewEuropeanDrivingCycle(NEDC,infigure2),itisclearthatlow-torque/high-speedandlow-speed/high-torqueoperatingpointshavetobereachedmostlyduringthiscycle.

(7)

(8)

Figures1,2and3:Drive'soperatingpointsdistributionovertheNewEuropeanDrivingCycle(above).Thevaluesinthemaparetheefficienciesintheoperatingpoints.Thedistributionreferstoanelectricvehicleabletoreachamaxspeedof145km/h,havingamassof1090kg,providedwithone-speedtransmission.NewEuropeanDrivingCycle(left),constitutedbyfourconsecutiveurbandrivingschedulesandonehighwaydrivingschedule.OperatingpointsovertheNEDC(right)ofaMannesmannSachs25

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Vdc,permanent-magnettractiondrivepropellingtheelectricvehicledescribedabove.

Amoresignificantandusefulparameterforthequalityestimationofdrivesconceivedforvehicularapplicationsisanintegralcriteriarepresentingtheefficiencyoverthewholedrivingcycle.Thisisdefinedastheratiobetweentheintegralofthemechanicalpowerfurnishedandtheintegraloftheelectricalpowerabsorbedduringthewholedrivingcycle(Eq.9),

(9)

wherethepowerlossPlossdependsonspeed,torqueandbatteryvoltage.

Thedrive'sbasespeedrangeisthespeedrangeinwhichthedrivecandevelopaconstantmaximumtorque.Thefieldweakeningrangeisthespeedrangeinwhichthedrivecanfurnishaconstantmaximumpower.Thefieldweakeningratio(Eq.10)istheratiobetweenthemaximumspeedandthehighestspeedinthebasespeedrange(thebasespeed).Intractiondrives,inordertogetaverygoodclimbingability,itispreferabletohavethehighestpossiblefieldweakeningratio(>2.5).

(10)

whereisthegradientoftheroad.

Figure4:GeneralElectric83-kWACinductionmotor/inverterefficiencymapandcontinuoustorquecapability.ThedrivewastestedbyProfessorDougNelsonatVirginiaUniversityofTechnology(USA).Onthespeedaxisareindicatedthemaximumspeed(max)andthebasespeed().

Figures5and6:Wheels’operatingpointsovertheNEDC(left).Wheels’operating-pointdistributionovertheNEDC(right):electricvehiclehavingamassof1090kg.

Thedrive'soptimaloperatingpointisthepointinwhichthedrivereachesitspeakefficiency.Observingthewheels’operatingpointsandtheoperatingpointsdistributionovertheNewEuropeanDrivingCycle(figg.5-6)itisevidentthatthetractiondrivehastooperatemostlyinlow-powerregions.Invehicularapplicationsthereis,therefore,theneedtoutilisetractiondrivesinwhichthehighestefficiencyregionsaresituatedinthelow-powerarea.Afigureofmeritfortractiondrivesistheratiobetweenthecontinuouspowerandthepowerdevelopedintheoptimalpoint(Eq.11).

(11)

Ahighfoptisusuallyrelatedtoagoodtractiondrive,butmoreimportantistheshapeofthecontourlinesinadrive'sefficiencymap.Itcanbeshown[6]thatcomparingtwodriveswhoseefficiencymapsareinfigures7and8,althoughthedriveinfigure7hasalowerfopt(1.2)thanthedriveinfigure8(1.5)andcomparablepeakefficiencies,theenergyconsumptionofavehicleadoptingthefirstdriveislower,atleastoverurbandrivingschedules.Thisiswhyinthefirstdrivetheregionsofhighefficiencyareextendeddeeplyeveninlow-speedareas,themostimportantinurbantraffic.Theefficiencyfactorfoptcangiveafirsthintonhowgoodanelectricdrivefortractionpurposeswillberegardingtheenergy-efficiency.Itisnotanabsolutecriterionandcannotreplaceasimulationofthetotalenergyconsumptionoverdifferentdrivingschedules.

Figures7and8:58-kWpermanent-magnettractiondrive(left)and62-kWAC-inductiontractiondrive(right):efficiencymaps.

2 Theadoptionofmulti-speedtransmissions

Theadoptionofamulti-speedtransmissionallowstomoveinthetorque/speedplaneonedrive'soperatingpoint,correspondingtooneoperatingpointinthewheel'storque/speedplane,alongaconstantpowerhyperbola.Moregenerally,thevariousgearratioscanmovealongaconstantpowerhyperbolaonepointinthedrivetrain-e.g.batteries,drive,gearbox-operatingspacecorrespondingtooneoperatingpointinthetractionwheelstorque/speedplane.Agearboxofcoursecannotmovethispointtowardshigherorlowerpowers.

Lookingatthewheels'operatingpointsdistributionovertheNEDC(figures5and6)andovertheU.S.FederalUrbanDrivingSchedule(FUDS)(figures10and11)forexample,it'sclearthatallthepointscanbe"reached"withonlyonetransmissionratio-usuallythefinaldriveratio-adoptingatractiondrivehavingfweakgreaterthan2-2.5;butthe25-kWdriveadoptedintheprevioussimulationshastooverworkeventheovertorqueregiontoprovidethehighhighwaypowersintheNEDC(figure3)andtheFUDS-high-torquevaluesinurbantraffic(figure12)andshouldthusbeoversizedtobettersatisfythepowerrequirementsofthesecycles.Thedrive'soversizingconcernsthemaximumallowabletorqueonly:themaximumspeed,thebasespeedandfweakremainunchanged.

Figure9:U.S.FederalUrbanDrivingSchedule(FUDS).

Figures10and11:Tractionwheels’operatingpoints(left)andtractionwheels'operating-pointdistribution(right)overtheUSFUDS.

Figures12and13:Drive'soperatingpoints(left)anddrive'soperating-pointdistribution(thevaluesinthemapsaretheefficienciesintheoperatingpoints)overtheUSFUDS.

Clearlythesizingofavehiclehastofollowrulesdictatedbyperformanceconstraintsonaconstantgradeandonminimumaccelerationtimes.Thevariousdrivingscheduleshavebeenconceivedtomeasureexhaustemissionsandfuel(energy)consumptiononwell-defineddrivingconditions.Theyshouldnotbeusedtosizethecomponentsofavehicle,becauseusuallytheperformancegoalsappliedinthesizingtechniquesaremorestringentthanthoserequiredtosatisfyadrivingcycle.Awell-sizedvehicleisthusableto"follow"usualdriving-cycletraceswithoutlacks.Ontheotherhand,forthisreasonatractiondriveoperatesoftenduringdrivingschedulesinpartial-load,inefficientregions.

Lookingattheshapeofthedrive'soperativeregionoveradrivingscheduleitisclearthateveryoperatingpointcanbereachedadoptingawell-sizedtractiondrivewithonlyonetransmissionratio.Thisiswhyusuallytheshapeoftheallowableoperatingregiononthedrive'storque/speedplaneisthesameasthetractionwheels'torque/speedoperatingregion.InconventionalvehiclestheICE(InternalCombustionEngine)operatingregiononthetorque/speedplaneisquitedifferent,andtosatisfytypicaldrivingschedulesthereistheneedtoadoptamulti-speedtransmissionwhichadjuststheICEoperatingregiontothetractionwheelsoperatingneeds.Thisisclearlookingforexampleatthemaximum-torqueenvelopeinaICEefficiencymap(figure14).

Figure14:Volkswagen1.9l,67-kWturbo-diesel-engineefficiencymap.

Theindividualtransmissionratiosarealwaysratedtoadjustthefullloadoutputcurveofthemulti-speedgearboxtoaconstantpowerhyperbola.Theshapeofthewheels'operatingregionisalwayscomprisedbelowaconstantpowerhyperbolaonthetorque/speedplane.Thetorquelimitsaredictatedbythemaximumtorqueatvehicle'sstartingongradesandthespeedlimitisdictatedbythemaximumvehicle'sspeed.

Tractiondriveswell-sizedhavingfweak>3cancoverthisenvelopewithonly1-speedgearbox(thefinaldrive).Inthesevehiclesthefinaldriveratioistheratiobetweenthemotor'smaximumspeedandthewheels'speedatmaximumvehicle'sspeed(Eq.12).

(12)

Withhighervaluesthemaximumvehicle'sspeedwouldnolongerbereached,althoughthetractionwheelswouldhavehighertorqueatdisposal.Furthermoretherotor'sandthegears'rotationalinertiamultipliedtothesquareofthetransmissionratioistransmittedontothewheels:whenshiftingfromthesecondtothefirstgear,kineticenergyofrotationisstoredintothedrivetrainandduringshiftingfromthefirsttothesecondgearisgivenout.Thelossesrelatedtothesechangesofspeedmustnotbedisregarded.Theproductofthe1stgearratiotothefinaldriveratio-inamulti-speedtransmission-orthefinaldriveratioina1-speedtransmissionshouldneverbegreaterthan15.

Adoptingadrivewithinsufficientfweakandtoolowmaxforcesthusthedesignertooversizeit,inordertoallowavehicleprovidedwitha1-speedtransmissionmerelytomeetconstantgradeperformances.

Inconventionalvehiclesthestep()betweentwosuccessivetransmissionratios(Eq.13)canbedesignedaccordingtotwodifferentrules:

thegeometricalrating;

theprogressiverating.

(13)

Inthegeometricalratingisconstantforalltheratiosandafterselectingthenumberofgearsitcanbeobtainedthebestadjustmentofthefullloadcurve(e.g.themaximumtorqueenvelopeinfigure14)toahyperbolaofconstantpower.Thiskindofdesignisfrequentintrucks'gearboxes.Inpassengervehiclesthegeometricalratingwouldforcetoadoptahighnumberofgearstoapproximateaconstantpowerhyperbola,sincethehighesttorqueinvehicles'enginesisusuallyreachedatveryhighspeeds.Inmodernautosisthuspreferredtheprogressiverating,whichprogressivelyreducesforthehighestgears.

Multi-speedtransmissionisthusacriticalissueinconventionalandparallelhybriddrivetrainsbutitsadoptioncouldbeusefuleveninelectric,serieshybridandfuelcellvehicles.Inthesepowertrainsthetractionpowerisfurnishedonlybyanelectricaldriveandamulti-speedgearboxassembledonthedrive'sshaftcouldallow

tocompensateforinsufficientfweakorPclimb;

toreachthemostefficientdrive'soperatingregions.

Inanelectricvehicleforexamplea2-speedtransmissioncouldbeadoptedtomeetboththefollowingrequirements:thesecondgearratiocanbechosentoallowthemaximumspeedtothevehicle,whilethefirstgearratiocanbechosentomeetthemaximumtractiveforceatlowspeeds:themaximumclimbingabilityatlowspeeds.

Inordertobetterexplainthepreviousassertionsletusconsiderthesameelectricvehiclewhosesimulationresultsareshownabove,adoptingthe33kWtractiondrivewhoseefficiencymapisinfigure17anda1-speedtransmissionwhoseratio(thefinaldriveratioinEq.14:ithasbeenassumed10%wheelslipand0.282mwheelradius)allows145km/hvehicle'smaximumspeed.AfterrunningasimulationovertheUSFUDS(figure9)withthisvehicle,areobtainedtheresultsshowninfigures15and16.

(14)

Figure15,16and17:DifferencebetweenrequestedandachievedspeedsovertheUSFUDS(above),drive'soperatingpoints(left):1-speedtransmission,=4.Siemens33

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Vdc,permanent-magnetmotor/controllerefficiencymap(right),driveintheVWGolfCitySTROMers,TypA3.

Althoughthisseconddrivecanprovideahighermaximumpower(Pcont=Pmax=33kW)thanthefirst(Pcont=25kW,Pmax=30kW)atthesameoperatingvoltage(130Vdc),thevehiclecannotsatisfactorilymeettheFUDSspeedrequirements.ThisiswhytheSiemensdrivecanprovideamaximumtorqueofonly80NmwhiletheMannesmanndrivedevelopsmorethan100Nmmaximumtorque,decreasingatincreasingspeeds.ThevehicleprovidedwiththisSiemensdrivecannotmeettheaccelerationsnecessaryinthecycleandmissedtheFUDStracebynearly20km/h(figure15).

Letusnowsupposetoassembleonthedrive'sshafta2-speedgearbox.Thetransmissionratiosarechosensoastoallowthesamevehicle'smaximumspeedandtomeettheaccelerationrequirementsintheFUDS.Iftheoverallratios(gearratiosfinaldriveratio)are

(15)

andlookingatthesimulationresultsinfigures18,19and20itcanbeassumedthattheFUDStraceisnowsatisfactorilymet.

Ithasbeenassumedthe2-speedgearboxhasamassof40kgandthevehicle'smassisthusincreasedbythisvalueinthesimulation.Thedependenceoftheshiftcommand(up,down,ornoshift)uponcurrentgear,motorspeedandloadassumingthecurrentgearismaintained,isimplementedusingone-dimensionallookuptable,oneforeachgear.Infigure19thenumberedcurvesareefficiencycontoursandtheupshiftanddownshiftlinesaredrawninthemotortorqueandspeedspace.Althoughtheplot'sy-axisismotortorque,theshiftlinesareinfactdefinedintermsofmotorload,whichisdefinedhereasthemotortorqueatagivenspeeddividedbyitsmaximumtorqueatthatspeed.Sotheactualupshiftanddownshiftlinesarenotstraightinmotortorque/speedspace,sincethemaximummotortorquedependsonspeed.Whenthemotortorque/speedoperatingpointwouldfalltotherightoftheupshiftcurve,anupshiftiscommanded.Likewise,whenthemotortorque/speedoperatingpointwouldfalltotheleftofthedownshiftcurve,adownshiftiscommanded.Thepositionoftheshiftlinesonthemotorspeed-axishasbeenchosensoastoforcethedrivetooperateasmuchaspossibleinitsoperatingregionwheretheefficiencydoesnotfallbelow10%ofitspeakefficiency.Anautomatedorrobotisedgearboxcouldimplementthiskindofoperation.

Figures18,19and20:DifferencebetweenrequestedandachievedspeedovertheUSFUDS(above):2-speedtransmission,1=8,2=4.Drive's(left)andtractionwheels'(right)operatingpoints.Thepointsinredaretransmittedthroughthefirstgear,thepointsingreenthroughthesecondgear.

Thevehicle'smodelentailsalsothegearboxofamulti-speedtransmissionwhichhousesgearsofdifferentgearratiosthatareusedtotransmittorquefromthetractivemotortothefinaldriveandontothewheels.Ittherebyallowsanumberofdiscretespeedreductionandtorquemultiplicationfactors.Effectsontorqueandspeedinthegearboxinclude:

torquemultiplicationandspeedreductionviathegearratio,

torquelossduetotheaccelerationofrotationalinertia,and

torquelossduetothefrictionoftheturninggears.

Theseeffectsaremodeledempiricallyandthenecessaryphysicalparameters[7]arebasedonaVolkswagen4-speedmanualtransaxleandsuppliedbydatafiles.IntheVWtransaxle,efficiencyisfairlyindependentoftorqueandspeedathightorques.

Table1summarisestheenergyuseofdrivesandgearboxesovertheU.S.FUDSforvariouslayouts.Thedatacontainedinthetablemustnotbeintendedasacomparisonamongdrives(figures17-21-22-23)fromdifferentmanufacturers.Thedrive-efficiencymapsareratedfordifferentdcvoltages.Thepeakefficiency,themaximumpowerandthecontourmapsdiffernotablyatdifferentoperatingvoltages:thepeakefficiencyandthemaximumpowerincreasewhilethehighestefficiencyregionsspreadatincreasingvoltages.Nonethelesstheefficiencyofthesepermanent-magnet-synchronousdrivesiscomparablewhendataareadjustedforvoltages.TheSachsdrive,forexample,isdeclaredtoreachapeakefficiencyhigherthan93%atvoltageshigherthan230Vdc[8].

DatainTable1refertothepowermodebehaviourastheefficiencymapsareusuallymeasured-orpublished-forpositivetorquevaluesonly.Forthisreason,inthemapsshowninthesepagestheregenerativeareasarerepresentedassumingthatlossesaresymmetricaboutzero-torqueaxis,butthisassumptiondoesnotallowtotrustdrive'sregen-lossdataresultingfromthesimulations.

FromTable1appearsthattheenergyactuallytransmittedbythefinaldriveontothetractionaxle(EnergyOut)differsslightly,althoughthesimulationsrefertothesamedrivingschedule.Thisiswhyithasbeenassumedthecycleissuccessfullymetifthespeedtraceisnotmissedformorethan2mph(3.2km/h).Thetraceisalwaysmetwithinthistolerance,butthelittledifferencesintheactual-speedtracesandtheslightmass-differenceamongvehiclesprovidedwithdifferentdrivesandtransmissionshavecausedthelittledifferenceintheenergyactuallytransmittedtothewheels.

LookingattheresultsinTable1itisclearthattheadoptionofa2-speedtransmissionusuallyallowsanincreaseintheenergy-conversionefficiencyintothedrive,thoughsometimesatexpenseofaslightincreasedenergylossduetotheintroductionofthegearbox.

AstudyontheSiemensdriveoversizedto60kW,asresultfromahypotheticalvehicle'ssizing,showsthattheadoptionofa2-speedtransmissioncanincreasetheenergy-conversionefficiencyintothedriveby4%overtheFUDS(Table2)andby2%overtheNEDC(Table3).

Figures21,22and23:UniqueMobilitySR218N/CA40-300L(leftabove)permanent-magnetmotor/controllerefficiencymap;Pcont=36kW,Pmax=53kW@300Vdc;peakefficiency94%.MannesmannSachsD260REL55(rightabove)permanent-magnetmotor/controller;Pcont=25kW,Pmax=30kW@130Vdc;peakefficiency90%.ToyotaPriuspermanent-magnetmotor/controller(left),testedbyNREL(USNationalRenewableEnergyLaboratory)atUniqueMobilityonApril1999;30kW@288Vdc;peakefficiency91%.

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Table1:EnergyusageindriveandgearboxovertheU.S.FederalUrbanDrivingSchedule

Component

Type

EnergyIn(kJ)

EnergyOut(kJ)

EnergyLoss(kJ)

Efficiency()

Motor/controller(oversized)

Finaldrive

Siemens58kWPM

1-spd(=4)

6621

4651

4651

4355

1970

297

0.7

0.94

Motor/controller

Gearbox+finaldrive

Siemens33kWPM

2-spd(1=8,2=4)

6182

4685

4685

4313

1497

371

0.76

0.92

Motor/controller

Gearbox+finaldrive

Siemens33kWPM

2-spd(1=9,2=4)

6219

4698

4698

4310

1521

388

0.76

0.92

Motor/controller

Finaldrive

Sachs25kWPM

1-spd(=4)

5454

4418

4418

4125

1036

293

0.81

0.93

Motor/controller

Gearbox+finaldrive

Sachs25kWPM

2-spd(1=6,2=4)

5553

4573

4573

4239

981

334

0.82

0.93

Motor/controller

Gearbox+finaldrive

Sachs25kWPM

2-spd(1=8,2=4)

5543

4581

4581

4239

962

341

0.83

0.93

Motor/controller

Gearbox+finaldrive

Sachs25kWPM

2-spd(1=4.5,2=3)

5537

4541

4541

4239

996

301

0.82

0.93

Motor/controller

Gearbox+finaldrive

Un.Mob.36kWPM

1-spd(=5)

5210

4490

4490

4171

720

319

0.86

0.93

Motor/controller

Gearbox+finaldrive

Un.Mob.36kWPM

2-spd(1=7,2=3.5)

5342

4640

4640

4285

702

355

0.87

0.92

Motor/controller

Gearbox+finaldrive

Un.Mob.36kWPM

2-spd(1=6.7,2=4)

5347

4638

4638

4285

709

353

0.87

0.92

Motor/controller

Finaldrive

Prius30kWPM

1-spd(=4)

5214

4453

4453

4159

761

294

0.85

0.93

Motor/controller

Gearbox+finaldrive

Prius30kWPM

2-spd(1=6,2=4)

5300

4610

4610

4274

690

336

0.87

0.93

Motor/controller

Gearbox+finaldrive

Prius30kWPM

2-spd(1=6,2=3)

5293

4605

4605

4274

688

332

0.87

0.93

Table2:Energyusageindrive(oversized)andgearboxovertheU.S.FederalUrbanDrivingSchedule

Component

Type

EnergyIn(kJ)

EnergyOut(kJ)

EnergyLoss(kJ)

Efficiency()

Motor/controller

Finaldrive

Siemens60kWPM

1-spd(=4)

6641

4662

4662

4365

1980

297

0.7

0.94

Motor/controller

Gearbox+finaldrive

Siemens60kWPM

2-spd(1=5,2=3)

6605

4802

4802

4477

1803

325

0.73

0.93

Motor/controller

Gearbox+finaldrive

Siemens60kWPM

2-spd(1=6,2=3)

6542

4826

4826

4477

1716

349

0.74

0.93

Motor/controller

Gearbox+finaldrive

Siemens60kWPM

2-spd(1=7,2=3)

6528

4834

4834

4477

1694

357

0.74

0.93

Motor/controller

Gearbox+finaldrive

Siemens60kWPM

2-spd(1=7,2=4)

6517

4836

4836

4477

1681

360

0.74

0.93

Motor/controller

Gearbox+finaldrive

Siemens60kWPM

2-spd(1=8,2=4)

6577

4851

4851

4477

1726

374

0.74

0.92

Table3:Energyusageindrive(