Page - 16 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 1217 Table3.Advantagesandlimitationsofparallelhybridconfiguration.Adaptedfrom[30]. Advantages Capableofattainingzeroemission Economicgain Moreflexibility Limitations Expensive Complexcontrol Requirementofproperalgorithms Needofhighvoltage toensureefficiency Table4.Comparisonofparallelandserieshybridconfigurations.Data from[8]. Parameters ParallelHEV SeriesHEV Voltage 14V,42V,144V,300V 216V,274V,300V,350V,550V,900V Powerrequirement 3KW–40KW >50KW Relativegain in fueleconomy(%) 5–40 >75 3.2.3. Series-ParallelHybrid Inaneffort tocombinetheseriesandtheparallelconfiguration, thissystemacquiresanadditional mechanical link compared to the series type, or anextrageneratorwhencompared to theparallel type. Itprovides theadvantagesofboththesystemsbut ismorecostlyandcomplicatednonetheless. Complications indrive trainarecausedtosomeextentbythepresenceofaplanetarygearunit [30]. Figure20showsaplanetarygeararrangement: thesungear isconnectedto thegenerator, theoutput shaftof themotor is connected to theringgear, the ICE is coupled to theplanetarycarrier, andthe piniongearskeepthewholesystemconnected.Alesscomplexalternative to thissystemis tousea transmotor,which is afloating-stator electricmachine. In this systemtheengine is attached to the stator,andtherotorstaysconnectedto thedrive trainwheel throughthegears. Themotorspeedis therelativespeedbetweentherotorandthestatorandcontrolling itadjusts theenginespeedforany particularvehiclespeed[30]. Series-parallelhybriddrive trainwithplanetarygearsystemisshownin Figure21;Figure22showsthesystemwitha transmotor. Figure20.Planetarygearsystem[31]. 16