Page - 172 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 5 7LPH V H[SHULPHQWDO GDWD FRQYHQWLRQDO ILWWLQJ IXQFWLRQ LPSURYHG ILWWLQJ IXQFWLRQ (a) 7LPH V H[SHULPHQWDO GDWD FRQYHQWLRQDO ILWWLQJ IXQFWLRQ LPSURYHG ILWWLQJ IXQFWLRQ (b) 7LPH V FRQYHQWLRQDO ILWWLQJ IXQFWLRQ LPSURYHG ILWWLQJ IXQFWLRQ (c) Figure12.Voltagecurvesofonecycleof thedischargingpulse-rest test (62%–60%): (a) theoverview; (b) aclose look; (c) thevoltageacross the long-termRCnetwork. 4.2.ModelVerification In thispaper, theCCchargingtestandtheconsecutiveUDDStest,whichrespectivelyrepresent two typical operating scenarios inHEV/EV applications, are conducted separately to verify the effectiveness of themodel. For the charging condition, thebattery is charged from10%–90%SoC. The typical chargingcurrent inpracticevaries fromC/8to2C[50], andaC/2ratecurrent isemployed inthechargingtest. TheconsecutiveUDDStest starts from90%SoC to20%SoC,witha10-minrest period inbetweentosimulateashortparkingtime. In therealapplication,aspecificsetofparameters canbeselectedbythecharacteristicsof themeasuredloadcurrent. Forexample, if thevaluesof the currentareapproximatelyconstantoveracertain time interval,parametersestimatedfromthedata in thepulse-chargingperiodsareemployed.Ontheotherhand,parametersestimatedfromthedata in therestperiodsareemployedwhenthe loadcurrentshowsthecharacteristicsofhighdynamicsovera certain timeinterval. Firstly, for theCCchargingscenario, threemodeloutputsandmeasuredbattery terminalvoltage curvesareplotted inFigure13,andthecorrespondingRMSEsaregiven inTable4. It canbeobserved that during thewhole charging process, themodel with parameters estimated from the data in pulse-charging periods outputs a voltage curvematching themeasured curve better because of consideringthecontinuousexternalelectricdrivingforces.However,parametersestimatedfromthe data in therestperiodsresult inrelatively largererrors, especially in thehighSoC region. Inaddition, duringmostpart of the chargingperiod, themodelwithparametersused in thedynamicdriving scenarios outputs a voltage higher than the experimental voltage. Comparing the corresponding curves inFigures8band11, it canbededucedthat thehigherestimatedvoltage ismainlycausedby the largervalueofestimatedRlong, especiallyduringthemiddlerangeof theSoC region. Table4.RMSEofmodelvoltageestimationunder theCCchargingtest. ModelingMethods DynamicCondition Rest-Period Pulse-Period RMSE(mV) 18.41 19.76 5.448 172