Seite - 290 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 997 Figure8.Thebatterymodeldiagram. Table8.Maincharacteristicparametersof thebattery. CharacteristicParameter Value CharacteristicParameter Value Capacity 8Ah Totalheatdissipationarea 1.6m2 Voltage 312V Specificheatcapacity 800 J/(kg·K) Mass 70kg Heat transfercoefficient 24W/(m2·K) 2.5. LongitudinalDynamicsModel ofVehicle This research focuseson the fuel economyof theHEV, thusonly the longitudinaldynamics is considered in thevehiclemodel, regardlessof theverticalvibrationandhandlingstability.According to thevehiclekinematicsequation[29],wehave: Ft=mgfcosα+ CDA 21.15 u2+mgsinα+δmu, (9) whereFt is thedrivingforce,m is the totalmassof thevehicle, f is therollingresistancecoefficient,α is theslopeangle,A is thevehicle frontalarea,CD is theairdragcoefficient,u is thevehiclespeed,andδ refers to thecorrectioncoefficientof rotatingmass. 2.6.DriverModel Thefunctionof thedrivermodel is tosimulate therealdriver’s controllability.Andthedriver modeldiagramisshowninFigure9. Thedrivercontrols theacceleratoror thebrakingpedalopening basedonthedifferencebetweentherealvelocityanddrivingcyclevelocity. Theproportional–integral (PI) controller is selectedfor thedrivermodel [30]. Thedrivermodelcanbedescribedas follows: α= kp(vtarget−v)+ki ∫ (vtarget−v)dt, (10) whereα is thepedalopening,withpositiveandnegativevalues representing theacceleratorpedal openingandbrakepedal opening, respectively; vtarget is the targetvelocity; v is the current actual speed;kp andki refer to theproportionalandintegral coefficientsof thePIcontroller, respectively. 290