Seite - 320 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 10 ȱ (b)ȱ Figure15. Purple curve: the chargingcurrents for thebatterypack; greencurve: the inputvoltage of theq-Zsource; cyancurve: theoutputvoltageproducedbytheHBridgemeasured(a)at the1μs shoot-throughtime;and(b) at the1.5μsshoot-throughtime. InFigure16a,b theq-Zsource inputvoltages (greencurve)are thesame,but theiroutputvoltages (cyancurve)aredifferentdueto thedifferentboost factors.Unlike thesquare-wavevoltagesproduced bytheHBridge, theq-Zsourceoutputvoltagesarepulsatileandalwayspositive. In theshoot-through state,where theq-Zsourceoutputvoltage equals zero, theq-Zsource input current (purple curve) increaseswithapositiveslope.However, itdecreaseswithanegativeslopewhentheq-Zsourceenters into thenon-shoot-throughstate. Figure17showstheoutputcurrents (purplecurve)andvoltages (cyancurve)producedbytheH Bridge,whichvalidate that thesystemisbasically in theresonantstate.However, thequasi-resonant state isnotbeneficial forsoft-switching,andhence,efficiency improvement. Inpractice, thecurrent producedbytheHBridgeshould lag thevoltage toacertaindegree, thusanadditional1nFcapacitor is added into the transmitter capacitor array in thispaper. Thegreencurve represents thevoltage across theq-Zsourcecapacitor (C2 inFigure6), andit is smaller thantheoutputvoltageproducedby theHBridge,but it isbigger thanthe inputvoltageof theq-ZsourceshowninFigure16. ȱ (a)ȱ Figure16.Cont. 320