Page - 63 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 1217 approach toattaindesiredperformance, stableSOCat therationaloperatingrangeconstantly, and maximizedfueleconomy. Theoperatingprincipleof this systemisshowninFigure72.Chenetal., proposedanenergymanagementalgorithmin[182] toeffectivelycontrolbatterycurrent, andthus reduce fuelusagebyallowingtheengineoperatemoreeffectively.Quadraticprogrammingwasused here to calculate the optimumbattery current. In [183], Li et al., used fuzzy logic to create anew quantity: batteryworking stateorBWSwhichwasused inanenergymanagement systemrunby fuzzy logic toprovideproperpowerdivisionbetweentheengineandthebattery. Simulationresults proved this approach tobe effective inmaking the engineoperate in the regionofmaximumfuel efficiencywhilekeepingthebatteryawayfromexcessdischarging.Yuanetal., comparedDynamic ProgrammingandPontryagin’sMinimumPrinciple (PMP) forenergymanagement inparallelHEVs usingAutomaticManualTransmission. ThePMPmethodprovedbetteras itwasmoreefficient to implement, requiredconsiderably lesscomputational time,andbothof thesystemsprovidedalmost similar results [184]. In [185],Bernardetal.,proposedareal timecontrol systemtoreducehydrogen consumption inFCEVsbyefficientlysharingpowerbetweenthe fuel cell arrangementandtheenergy buffer (ultracapacitor orbattery). This control systemwas created fromanoptimal control theory basednon-causaloptimizationalgorithm. Itwaseventually implemented inahardwarearrangement built arounda600Wfuel cell arrangement. Inanattempt tocreateanenergymanagementsystem for a still-not-commercialized PHEVemploying amicro turbine, Geng et al., used an equivalent consumptionminimization strategy (ECMS) in [174] to estimate the optimumdriving cost. Their systemusedthebatterySOCandthevehicle telemetry toproduce theresults,whichwereavailable in real timeandprovideddrivingcost reductionsofupto21.6%. Figure 65. Forces acting on thewheels of a car. Each of thewheels experience forces in all three directions,markedwith the ‘F’vectors. Lf andLr showthedistancesof frontandrearaxles fromthe centerof thevehicle,whileTr showsthedistancebetweenthewheelsofanaxle.Adaptedfrom[25]. 63