Page - 175 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 5 H[SHULPHQW FRQYHQWLRQDO LPSURYHG K LPSURYHG K 7LPH V (c) Figure15.Verificationresultsofdifferentparameterestimationmethodsunder theUDDStests: (a)The overall look; (b)ThecalculatedSoCprofile (c)Theclose look. Table 5. RMSEof themodel voltage estimation under the urbandynamometer driving schedule (UDDS) test. ModelingMethods Conventional Improved-2h Improved-1h RMSE(mV) 8.504 6.329 4.244 5.Conclusions In thispaper,anadvancedbatteryparameterestimationmethodbasedontwogeneraloperating scenarios inHEV/EVapplications isproposed. Firstly, thesecondorderECMisemployed,andthe modelparameterextractionprocess isdescribed indetail. Considering the typicaloperatingscenarios inHEV/EVapplications,namely theCCchargingscenarioandthedynamicdrivingscenario, two setsofmodelparametersareextracted fromthecharging/dischargingpulse-rest tests. Specifically, voltage responsesof thepulse-chargingphasesare selected toestimatemodelparameters applied intheCCchargingscenario. For thedynamicdrivingscenario, themodelparametersare identified throughthemeasureddata fromtherestperiod. Insteadofemployingthedata fromthewholerest period, only theprior portionof the collecteddata is selected, and the length of thefitteddata is determinedbythefrequencyspectrumanalysisof the loadcurrentunder twotypicalurbandriving conditions. Inaddition,anunsaturatedphenomenoncausedbythe long-termRCnetwork isanalyzed indetail, andsubsequently,an improvedfittingequationwithmoreaccurate initialvoltageexpression of theRCnetwork isadopted. Finally,verificationtestssimulatingtheCCchargingscenarioandthe dynamicdrivingscenarioare conducted, respectively, andcomparisonsbetween theconventional andtheproposedbatteryparameterestimationmethodsaregiven. Experimental results showthat in bothcases, thevoltageprofilespredictedfromtheproposedmodelshowabetterconformity to the experimentaldata. It is important tonote that theproposedbatteryparameterestimationmethodfor thedynamic drivingscenarioonlyconsidersthetypicalurbandrivingconditionsatroomtemperature.However,the characteristicsof the loadcurrentunder theother special conditions (suchas thehighwaydriving condition and the extremely cold condition)will be obviouslydifferent. For the futurework, the 175