Seite - 286 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 997 Te= 1 τes+1 f(ωe,α), (1) whereTe is theengineoutput torque;ωe is theenginespeed;α is the throttleopening;τe is the time constantof theengine torqueresponse; f isa functionof theengine torquecharacteristic. Thedataregardingtheexternalcharacteristic, fuelconsumption,andemissionsareacquiredfrom theexistingengine test. Then, theworkingcharacteristicof theengine isobtainedbya lookuptableor fitting. Thecurrentmaximumtorqueandfuelconsumptionrateof theenginecanbeacquiredbya lookuptableaccordingto thecurrentenginespeedandtorque in theSimulinkmodel. Figure2shows theengine fuelconsumptionratecurveandexternalcharacteristic curveusedin themodel. Figure2.Engine fuelconsumptionratecurveandexternalcharacteristic curve. 2.2.MotorModel Both the ISGandin-wheelmotorsarepermanentmagnetsynchronousmotors. Themotormodel isestablishedaccordingtothedataofmotorefficiency. Thedynamiccorrection isdoneviaafirst-order inertia link[26]. Tm= ⎧⎨ ⎩ 1 τms+1min(Tmr,Tdismax(ωe)) Tmr>0 1 τms+1max(Tmr,Tchmax(ωe)) Tmr<0 , (2) whereTm is theoutput torqueof themotor;Tmr is the required torqueof themotor; τm is the time constantof themotor;Tdismax(ωe) is themaximumoutput torqueof themotorat thespeedωewhen discharging;Tchmax(ωe) is theminimumoutput torqueof themotorat thespeedωewhencharging. Themotorpowercanbecalculatedbasedonthe followingequation: Pm= ImUm= ⎧⎨ ⎩ Tmωe 9550ηm , Tm≥0 Tmωeηm 9550 , Tm<0 , (3) where Im is themotor current;Um is the bus voltage; ηm refers to themotor efficiency; Pm is the motorpower. The working efficiency and external characteristic curves of the ISG and in-wheel motors, whichareshownbelowinFigures3and4, respectively,areobtainedfromtheexperiment. 286