Page - 292 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 997 Figure11.Workingareadivisionfornickel-metalhydridebatterypack. 3.1.1. ParsingofDriver’s Intention In theprocessofdriving, thedriver showshis orher accelerationordecelerationdemandby manipulating theacceleratorpedalorbrakingpedal. Therefore, toparse thedriver’sdemand, it is necessary to transfer thepedal signal intovehicledemandtorques,whichcanbedivided intodriving demandtorqueandbrakingdemandtorque. Inorder to identify thedemandtorque, thepedal signal is normalized, and is expressedas α,within (−1, 1). Thepositivevalue represents the accelerator pedalopeningwhile thenegativevalue is for thebrakingpedalopening. Inorder tomaintain the driver’s reactionwhenoperatingthepedalandobtain thesamedynamicpropertiesas theprototype, weconsider theengineexternalcharacteristiccurveas thedriver’smaximumdemandtorquecurve forHEVs. Therefore,when thedriver controls the accelerator pedal, thedemanddriving torque canbe representedas Tcmd=αTemax, (11) whereTcmd is thedemanddrivingtorque,α is theacceleratorpedalopening,andTemax is theengine maximumtorque. Whenthedrivercontrols thebrakingpedal, thedemandbrakingtorquecanberepresentedas Tcmd=α(TMaxGen+TMaxMechBrake), (12) whereTcmd is thedemandbrakingtorque,α is thebrakingpedalopening,TMaxGen is themaximum regenerativebrakingtorque,andTMaxMechBrake refers to thehighestmechanicalbrakingtorque. Fortheall-wheeldrivefull-HEV,theenergymanagementstrategydistributesthedriver’sdemand brakingtorqueto theengine, ISGmotor, in-wheelmotor,andmechanicalbrakingsystem. Thedemanddrivingtorque isas follows: Tcmd=Te+TISG+Thubmotor/ioig, (13) Thedemandbrakingtorque ispresentedas follows: Tcmd=TISGGenioig+ThubmotorGen+TMechBrake, (14) whereTe,TISG, andThubmotor are thedrivingtorquesprovidedbytheengine, ISGmotor,andin-wheel motor, respectively;TISGGen,ThubmotorGen, andTMechBrake refer to thebrakingtorquesprovidedbyISG motor, in-wheelmotor,andmechanicalbrakingsystem,respectively; io and ig are thegear ratiosof the mainreducerandAMTgearbox, respectively. 292