Seite - 232 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 410 (a) (b) Figure 16. Measuredwaveformsof the studiedBDC in charge state at full load: (a) low-sidefilter currents iLa, iLb; (b)gatesignalsofQ1,Q2 andtwo-phase inductorcurrents iL1, iL2. Figures17and18showthesimulatedandmeasuredwaveformsofcharge-pumpcapacitorvoltage (VCB),middle-linkvoltage (VM),middle-linkcapacitorvoltages (VM1,VM2), low-sidevoltage (VL), andlow-sideswitchvoltages (VS1,VS2,VS3,VS4). FromFigures17and18with theULCofstudied BDC, the low-voltageside (VL) iswell regulatedat48V.Themiddle-linkvoltage is96V, itdoesquite reachtwiceof theregulated low-sidevoltage(VL)of48V.Thecharge-pumpcapacitorvoltage(VCB) of192Vcanbeachievedeasilyandindeedcanshareone-halfof thehigh-sidevoltage toreduce the voltagestressofactiveswitches. It isobservedthat thesteady-statevoltagestressesof low-sideactive switches (VS1,VS2,VS3,VS4)areonlyabout48V,whichmeans that loweron-resistanceMOSFETscan beusedtoachieve the improvedconversionefficiency.Also,both thesimulatedresultsare inclose agreementwith thecorrespondingexperimental results. 232