Hybrid Electric Vehicles 2

ElectricalCircuitTheory1HybridelectricvehiclesAnextracreditpresentationbyHarryPapacharissiouWithsupplementationbyAndrewNafalskiElectricalCircuitTheory2Hybridelectricvehicles•WhatisaHEV?•WhyHEV’s•AdvantagesofusingHEV’s•TypesofHEV’s•HEVcomponents•ThefutureofHEV’sElectricalCircuitTheory3WhatisaHEV?•Hybridelectricvehicles(HEVs)combinetheinternalcombustionengineofanormalvehiclewiththebatteryandelectricmotorofanelectricvehicle.•Thisresultsintwicethefueleconomyofconventionalvehicles.•Alsoofferstheextendedrangeandrapidrefuellingthatconsumersexpectfromanormalvehicle,withalltheenergyandenvironmentalbenefitsofanelectricvehicle.•Canbeusedinawiderangeofapplications,frompersonaltransportationtocommercialhauling.ElectricalCircuitTheory4HybridElectricVehicle•Combinationofpetrolengineandelectricmotor•Energydensity–Petrol-12,500Wh/kg–LeadAcidbattery-25Wh/kg–Nickel-metalhydridebattery–44Wh/kg•Serieshybrids:petrolenginedrivesalternatortostoreenergyinbatteriesorsenttoelectricmotorwhichpowersthewheels.Petrolengineneversuppliesthewheelsdirectly.ElectricalCircuitTheory5WhyHEV’s?•Hybridpowersystemsweredesignedasawaytocompensatefortheshortfallinbatterytechnology.•Becausebatteriescouldsupplyonlyenoughenergyforshorttrips,anonboardgenerator,poweredbyaninternalcombustionengine,couldbeinstalledandusedforlongertrips.ThisistheconceptoftheHEV.•Electricvehiclesareonlybeingusedinselectedmarketapplicationswherefewerkilometresaretravelled.•Conventionalmotorvehiclespoweredbyinternal-combustionengines(ICE)posesubstantialeconomic,environmentalandenergysecurityissuesfortheplanet.ElectricalCircuitTheory6WhyHEV’s?•Moreefficientcarscanmakeabigdifferencetosocietyintermsofenvironmentalbenefits,andthestateoftheurbanairhasmotivatedbuyerstopurchasecleanercars.•UseofproductionHEVswillreducesmog-formingpollutantsoverthecurrentnationalaverage.ElectricalCircuitTheory7WhyHEV’s?•Hybridswillneverbetruezero-emissionvehicles,however,becauseoftheirinternalcombustionengine.•Butthefirsthybridsonthemarketwillcutemissionsofglobal-warmingpollutantsbyathirdtoahalf,andlatermodelsmaycutemissionsbyevenmore.•TheHondaInsightElectricalCircuitTheory8HEVAdvantages•OneofthemostimportantdifferencesbetweenaHEVandanormalvehicleistheHEV'sabilitytoreclaimaportionoftheenergylosttobraking.•InaHEV,whenthedriverbrakes,themotorbecomesagenerator,usingthekineticenergyofthevehicletogenerateelectricitythatcanbestoredinthebatteryforlateruse.•Traditionalbrakesarenecessary,aswellasaconsistentstrategyforsmoothlyblendingthetwobrakingsystems.•Regenerativeandfrictionbrakesneedtobecontrolledelectronicallysothatstoppingabilityismaximizedtomakethedualbrakeoperationnotnoticeabletothedriver.ElectricalCircuitTheory9HEVAdvantages•Regenerativebraking(explainedabove)capabilityhelpsminimizeenergylossandrecovertheenergyusedtoslowdownorstopavehicle.•Enginescanbesizedtoaccommodateaverageload,notpeakload,whichreducestheengine'sweight.•Fuelefficiencyisgreatlyincreased(hybridsconsumesignificantlylessfuelthanvehiclespoweredbygasolinealone).•Emissionsaregreatlydecreased.•HEVscanreducedependencyonfossilfuelsbecausetheycanrunonalternativefuels.•SpeciallightweightmaterialsareusedtoreducetheoverallvehicleweightofHEVs.ElectricalCircuitTheory10TypesofHEV’s•ManyconfigurationsarepossibleforHEVs.•Essentially,ahybridcombinesanenergystoragesystem,apowerunit,andavehiclepropulsionsystem.•Theprimaryoptionsforenergystorageincludebatteries,ultracapacitors,andflywheels.•Althoughbatteriesarebyfarthemostcommonenergystoragechoice,researchisstillbeingdoneinotherenergystorageareas.Hybridpowerunitoptionsaresparkignitionengines,compressionignitiondirectinjectionengines,gasturbines,andfuelcells.ElectricalCircuitTheory11Practicalrealisations•Parallelhybrid:twopowerpathseitherengineormotor,orbothpowerthewheelsdirectly.•Serieshybridismoreefficientbutparallelhybridhashigherpoweroutputneededinpracticalconditions•HondaInsightvsToyotaPrius•Insightispureparallel;Priususescombinationofboth(enginepowersplitalongtwopaths–wheelsandalternatorwhichdrivestheelectricmotorandalsochargesthebatteries)ElectricalCircuitTheory12TypesofHEV’s•Propulsioncancomeentirelyfromanelectricmotor,suchasinainline(series)configuration,ortheenginemightprovidedirectmechanicalinputtothevehiclepropulsionsysteminaV(parallel)system.•ThereareseveraltransmissionoptionswhenitcomestoHEVsaswell—thedriverdetermineswhichtransmissionwillbemostefficient.•Ahybrid'sefficiencyandemissionsdependontheparticularcombinationofsubsystems,howthesesubsystemsareintegratedintoacompletesystem,andthecontrolstrategythatintegratesthesubsystems.•Ahydrogenfuelcellhybrid,forexample,wouldproduceonlywaterasaby-productandrunatgreateroverallefficiencythanabattery-electricvehiclethatuseswall-plugelectricity.ElectricalCircuitTheory13HEVComponentsElectricalCircuitTheory14HEVComponents•AHEVisanoptimisedmixofmanycomponents.Thevehicledrivetrainconsistsof:•Electrictractionmotors/controllers•Electricenergystoragesystems,suchasbatteries,ultracapacitors,andflywheels•Hybridpowerunitssuchassparkignitionengines,compressionignitio