Page - 37 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 1217 andGMforprovidingwireless facilities forNissanLeafandChevroletVoltmodels.However,with significantadvance in the technology,wirelesscharging is likely tobe integrated intheEVscenario, theconveniences itoffersare tooappealingtooverlook. Table21.Comparisonofwirelesschargingsystems. WirelessCharging System Performance Cost Volume/Size Complexity PowerLevel Efficiency EMI Frequency Inductivepower transfer (IPT) Medium Medium 10–50kHz Medium Medium Medium Medium/High Capacitivepower transfer (CPT) Low Medium 100–500kHz Low Low Medium Low Permanentmagnet couplingpower transfer (PMPT) Low High 100–500kHz High High High Medium/Low Resonant inductive power transfer (RIPT) Medium Low 1–20MHz Medium Medium Medium Medium/Low On-line inductivepower transfer (OLPT) Medium Medium 10–50kHz High High Medium High Resonantantennae power transfer (RAPT) Medium Medium 100–500kHz Medium Medium Medium Medium/Low For thecurrentEVsystems,on-boardACsystemsareusedfor the lowestpower levels, forhigher power,DCsystemsareused.DCsystemscurrentlyhavethreeexistingstandards [16]: • CombinedChargingSystem(CCS) • CHAdeMO(CHArgedeMOve,meaning: ‘movebycharge’) • Supercharger (forTeslavehicles) The powers offered by CCS and CHAdeMO are 50 kW and 120 kW for the Supercharger system[88,89].CCSandCHAdeMOarealsocapableofprovidingfastcharging,dynamiccharging andvehicle to infrastructure (V2X) facilities [6,90]. Most of the EV charging stations at this time provides level 2AC charging facilities. Level 3DC charging network, which is being increased rapidly, is also available forTesla cars. The stationsmayprovide theCHAdeMOstandardor the CCS, therefore,avehiclehas tobecompatiblewith theconfigurationprovidedtobechargedfromthe station. TheCHAdeMOsystemis favoredby the Japanesemanufacturers likeNissan,Toyotaand Hondawhereas theEuropeanandUSautomakers, includingVolkswagen,BMW,GeneralMotorsand Ford,prefer theCCSstandard.Reference[5]discusses thechargingsystemsusedbycurrentEVsalong with the timerequiredtoget themfullycharged. 7. PowerConversionTechniques Batteriesorultracapacitors (UC)storeenergyasaDCcharge.Normally theyhave toobtain that energyfromAClinesconnectedto thegrid,andthisprocesscanbewiredorwireless. Todeliver this energyto themotors, ithas tobeconvertedbackagain. Theseprocesseswork in thereversedirection aswell i.e.,powerbeingfedback to thebatteries (regenerativebraking)orgettingsupplied togrid whenthevehicle in idle (V2G) [91]. Typicalplacementofdifferent converters inanEVisshownin Figure39alongwith thepowerflowdirections. This conversioncanbeDC-DCorDC-AC.Forall thisconversionworkrequiredtofilluptheenergystorageofEVsandthentouse themtopropel the vehicle,powerconvertersarerequired[72],andtheycomeindifferent forms.Adetaileddescriptionof powerelectronicsconverters isprovidedin [92]. FurtherclassificationofAC-ACconverters is shown in[93].Adetailedclassificationofconverters is showninFigure40. 37