Seite - 317 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 10 ThecorrespondingTHDcalculationresultsatdifferent frequenciesareshowninFigure11,which clearly indicates that the lowestTHDhappensaround2μs~3μsnon-effective timesat50kHzand1 μs~2μsnon-effective timesat80kHz, rather than0μsnon-effective time. Theoptimalnon-effective time iswhereTHDhas thesmallestdecreasewith the increasingfrequencies. Becauseweadopt80 kHzas thesystemoperating frequency, thenon-effective timeshouldbedesignedaround1μs~2μs to reduceTHDaswellasharmonic loss. ȱ (a)ȱ (b) 0 1 2 3 4 5 6 30 40 50 60 70 Non-Effective Time (us) 0 1 2 3 4 30 40 50 60 70 80 Non-Effective Time (us) Figure11.THDsofsquarewaveswithdifferentnon-effective timesat50kHz(a) and80kHz(b). 4. Experiments Aprototypewas implemented to validate our research results, as shown in Figure 12, and themagneticcoilsaredesignedbasedonthenestedthree-layeroptimizationmethod,whichwillbe discussedinourotherpapers. TheprototypeisfabricatedaccordingtotheschematicshowninFigure6, where thepower source adopts a 62100H-600high-voltageDCpower supply (Chroma, Taoyuan, Taiwan), theHBridgeemploys fourSPW47N60C3MOSFETs (Infineon,Neubiberg,Germany), the resonantcapacitorsadoptB32672Lthin-filmseries (TDK-EPCOS,Tokyo, Japan) ,therectifierconsistsof four IDW30E65D1fast recoverydiodes (Infineon,Neubiberg,Germany)andthebatterypackconsists of24 lead-acidbatteryunits. Figure13showsthetransfercharacteristicsof thewirelesspowertransfersystemat20cmtransfer distance,andit isworthmentioningthat theq-Zsourcedoesnotwork,andisonlypresentasafilter. In Figure13a, the transferpower increaseswithrising inputvoltagesorbatterypackvoltages. Inpractice, thepowerfactorcorrection(PFC)with400Voutputvoltage isemployedtoenhanceACpowerquality, and the 300Vbatterypack iswidelyused formanyproduction-readyvehicles, likeToyotaPrius, ChevroletVolt,Mitsubishi i-MiEVaswellasNissanLeaf, thuswedefinethissituationas thesystem ratedoperatingstate. In theratedstate, thechargingpower is3220WasshowninFigure13a,which isa littlebigger than3kW,since thebatterypackvoltage increases from300Vto309.7Vwhenthe chargingcurrent (RMSvalue is10.4AasshowninFigure14)flows through thebattery resistance, causinganextravoltagedrop. Figure13bshowsthat the transferefficienciesarenearlyunchanged despite the increasing inputvoltagesorbatterypackvoltages, andtheratedefficiencywhere the input voltageequals400Vandthebatterypackvoltageequals300Visaround95%. 317