Page - 325 - in Emerging Technologies for Electric and Hybrid Vehicles

energies Article AnAutonomousCoilAlignmentSystemfor the DynamicWirelessChargingofElectricVehicles to MinimizeLateralMisalignment KaramHwang1, JaeyongCho1,DongwookKim1, JaehyoungPark1, JongHwaKwon2, SangIlKwak2,HyunHoPark3 andSeungyoungAhn1,* 1 GraduateSchool forGreenTransportation,KAIST,Daejeon34141,Korea;hwang8@kaist.ac.kr (K.H.); fable@kaist.ac.kr (J.C.);dwkim88@kaist.ac.kr (D.K.); jaehyoung.park@kaist.ac.kr (J.P.) 2 ElectromagneticEnvironmentResearch,ETRI,Daejeon34129,Korea;hjkwon@etri.re.kr (J.H.K.); sikwak@etri.re.kr (S.I.K.) 3 DepartmentofElectronicEngineering,UniversityofSuwon,Hwaseong18123,Korea;hhpark@suwon.ac.kr * Correspondence: sahn@kaist.ac.kr;Tel.:+82-42-350-1263 AcademicEditor: SheldonS.Williamson Received: 2 January2017;Accepted: 2March2017;Published: 7March2017 Abstract:Thispaperproposesanautonomouscoil alignment system(ACAS) forelectricvehicles (EVs)withdynamicwirelesscharging(DWC)tomitigate thereduction inreceivedpowercausedby lateralmisalignmentbetweenthesourceandloadcoils. Thekeycomponentof theACASisanovel sensorcoildesign,whichcandetect the loadcoil’s leftor rightpositionrelative to thesourcecoilby observingthechange involtagephase. Thisallowsthe lateralmisalignment tobeestimatedthrough thewirelesspower transfer (WPT) systemalone,which is anovel trackingmethod forvehicular applications. Oncemisalignment is detected, the vehicle’s lateral position is self-adjustedby an autonomous steering function. The feasibility of theoverall operationof theACASwasverified throughsimulationandexperiments. Inaddition, ananalysisbasedonexperimental resultswas conducted,demonstrating that26%moreenergycanbe transferredduringDWCwith theACAS, justbykeepingthevehicle’s loadcoilalignedwith thesourcecoil. Keywords: electricvehicle (EV);dynamicwirelesscharging(DWC);wirelesspower transfer (WPT); powerdegradation; coilmisalignment;magnetic sensing 1. Introduction With the realizationof electricvehicles (EVs) to reducegreenhousegases, significant research anddevelopmentdirected towards improvingEVs’ feaatureshasbeenconductedduringrecentyears. However,onemaindisadvantageofEVs is theirbattery technologydueto itshighcostandlimited driving range. Toovercome thementioned issues andminimizedependencyonbattery systems, manyhave lookedinto theutilizationof infrastructuresuchasvehicle togrid (V2G) [1],or residential distributiongridsystems[2].Dynamicwirelesscharging(DWC)forEVs isanotherpromisingmethod ofutilizing infrastructure toovercomebattery issues inEVs.DWCisawirelesspower transfer (WPT) systemthatallowsEVstobechargedwirelesslywhile inmotion.WithDWC,EVsare lessdependent onbatterysystemsbecause theyreceivepower fromtheroad.Asaresult,EVswithDWCoffer several advantagesoverconventionalEVssuchas lowervehiclecostandreducedchargingtimedueto their smallerbatterysystems[3–5]. In lightof themanybenefits it canprovide,extensiveresearchonWPT andDWChasbeenconductedatvarious institutionsaroundtheglobe. Furtherbenefitscanberealized whenDWCis implementedasanEVcharging laneonhighways [6]. If aDWClane is installedat Energies 2017,10, 315;doi:10.3390/en10030315 www.mdpi.com/journal/energies325