The State of the Art of Electric, Hybrid, and Fuel

TheStateoftheArtofElectric,Hybrid,andFuelCellVehiclesTheStateoftheArtofElectric,Hybrid,andFuelCellVehiclesWiththeirsuperiorfueleconomyandperformance,hybridvehicleswilllikelyincreaseinpopularityincomingyears;furtherdevelopmentofcontroltheoryforhybridsisessentialfortheirprogress.ByC.C.Chan,FellowIEEEABSTRACT|Withthemorestringentregulationsonemissionsandfueleconomy,globalwarming,andconstraintsonenergyresources,theelectric,hybrid,andfuelcellvehicleshaveattractedmoreandmoreattentionbyautomakers,govern-ments,andcustomers.Researchanddevelopmenteffortshavebeenfocusedondevelopingnovelconcepts,low-costsystems,andreliablehybridelectricpowertrain.Thispaperreviewsthestateoftheartofelectric,hybrid,andfuelcellvehicles.Thetopologiesforeachcategoryandtheenablingtechnologiesarediscussed.KEYWORDS|Electricdrives;electricmachines;electricvehicle;fuelcellvehicles;hybridelectricvehicle(HEV);modeling;powerelectronicsI.INTRODUCTIONComparedtoconventionalvehicles,hybridelectricvehi-cles(HEVs)aremorefuelefficientduetotheoptimizationoftheengineoperationandrecoveryofkineticenergyduringbraking.Withtheplug-inoption(PHEV),thevehiclecanbeoperatedonelectric-onlymodesforadrivingrangeofupto30–60km.ThePHEVsarechargedovernightfromtheelectricpowergridwhereenergycanbegeneratedfromrenewablesourcessuchaswindandsolarenergyandfromnuclearenergy.Fuelcellvehicles(FCV)usehydrogenasfueltoproduceelectricity,thereforetheyarebasicallyemissionfree.Whenconnectedtoelectricpowergrid(V2G),theFCVcanprovideelectricityforemergencypowerbackupduringapoweroutage.Duetohydrogenproduction,storage,andthetechnicallimitationsoffuelcellsatthepresenttime,FCVsarenotavailabletothegeneralpublicyet.HEVsarelikelytodominatetheadvancedpropulsionincomingyears.Hybridtechnologiescanbeusedforalmostallkindsoffuelsandengines.Therefore,itisnotatransitiontechnology.Fig.1showstheroadmapofhybridtechnologies.InHEVsandFCVs,therearemoreelectricalcom-ponentsused,suchaselectricmachines,powerelectronicconverters,batteries,ultracapacitors,sensors,andmicro-controllers.Inadditiontotheseelectrificationcomponentsorsubsystems,conventionalinternalcombustionengines(ICE),andmechanicalandhydraulicsystemsmaystillbepresent.Thechallengepresentedbytheseadvancedpropulsionsystemsincludeadvancedpowertraincompo-nentsdesign,suchaspowerelectronicconverters,electricmachinesandenergystorage;powermanagement;mod-elingandsimulationofthepowertrainsystem;hybridcontroltheoryandoptimizationofvehiclecontrol.Thispaperprovidesanoverviewofthestateoftheartofelectricvehicles(EVs),HEVsandFCVs,withafocusonHEVs.SectionIItriestoanswerafundamentalquestion:whyEV,HEV,andFCV?ItalsolooksatthekeyissuesofHEVsandFCVs.SectionIIIreviewsthehistoryofEVs,HEVs,andFCVs.SectionIVhighlightstheengineeringphilosophyofEVs,HEVs,andFCVs.SectionVpresentsthearchitecturesofHEVsandFCVs.SectionVIprovidesanoverviewofthecurrentstatusofHEVsandFCVs.SectionVIIdiscussesthekeytechnologies,includingelec-tricmotortechnology,powerconvertertechnology,controlandpowermanagementtechnology,andenergystoragedevices.Finally,conclusionsaregiveninSectionVIII.II.WHYEVs,HEVs,ANDFCVs?Vehiclesequippedwithconventionalinternalcombustionengines(ICE)havebeeninexistenceforover100years.Withtheincreaseoftheworldpopulation,thedemandforManuscriptreceivedAugust8,2021;revisedDecember28,2021.TheauthoriswiththeInternationalResearchCentreforElectricVehicles,UniversityofHongKong,HongKong,andtheHarbinInstituteofTechnology,WuhanUniversity,China(e-mail:[e-mail]).DigitalObjectIdentifier:10.1109/JPROC.2021.892489704ProceedingsoftheIEEE|Vol.95,No.4,April20210018-9219/$25.00ó2021IEEEvehiclesforpersonaltransportationhasincreaseddramat-icallyinthepastdecade.Thistrendofincreasewillonlyintensifywiththecatchingupofdevelopingcountries,suchasChina,India,andMexico.Thedemandforoilhasincreasedsignificantly.Anotherproblemassociatedwiththeever-increasinguseofpersonalvehiclesistheemissions.Thegreenhouseeffect,alsoknowasglobalwarming,isaseriousissuethatwehavetoface.Therehavebeenincreasedtensionsinpartoftheworldduetotheenergycrisis.Governmentagenciesandorganizationshavedevel-opedmorestringentstandardsforthefuelconsumptionandemissions.Nevertheless,withtheICEtechnologybeingmaturedoverthepast100years,althoughitwillcontinuetoimprovewiththeaidofautomotiveelectronictechnology,itwillmainlyrelyonalternativeevolutionapproachestosignificantlyimprovethefueleconomyandreduceemissions.Battery-poweredelectricvehicleswereoneofthesolutionsproposedtotackletheenergycrisisandglobalwarming.However,thehighinitialcost,shortdrivingrange,longcharging(refueling)time,andreducedpassengerandcargospacehaveprovedthelimitationofbattery-poweredEVs.TheHEVwasdevelopedtoovercomethedisadvantagesofbothICEvehiclesandthepurebattery-poweredelectricvehicle.TheHEVusestheonboardICEtoconvertenergyfromtheonboardgasolineordieseltomechanicalenergy,whichisusedtodrivetheonboardelectricmotor,inthecaseofaseriesHEV,ortodrivethewheelstogetherwithanelectricmotor,inthecaseofparallelorcomplexHEV.Theonboardelectricmotor(s)servesasadevicetooptimizetheefficiencyoftheICE,aswe