Page - 322 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 10 Figure 18a indicates that the charging power or current can be adjusted by changing the shoot-through times. Take the 200V input voltage as an example, the charging current is 5.26A whenthere isnoshoot-throughtime,andit is increasedto8.26Awith1μsshoot-throughtime,andit is further increasedto10.2Awhentheshoot-throughtimeis1.5μs. Because theboost factor isclose to 2at1.5μsshoot-throughtime, the inputvoltagesabove200Varenotallowed,whichmaydamagethe resonatecapacitors. InFigure18b, theefficienciesdeclinewith the increasingshoot-throughtimes, for theshoot-throughstatemakes theMOSFETsof latterbridgearmlost their soft-switchingconditions. Additionally, theoperating frequency(160kHz)ofq-Zsourcedoubles that (80kHz)ofwirelesspower transfersystem,whichfurthercauses thedecline in the transferefficiency. Thisphenomenoncanbe suppressedby reducing theoperating frequencyofq-Zsouce. If it isdecreased to40kHz, the loss canbe theoretically reducedasmuchas four times.However, thereductionof the frequencyrequires bigger inductorsandcapacitors thanbefore, thus theq-Zsourceparametersneedtobere-optimized, which isour futurework. ȱ (a)ȱ ȱ (b)ȱ 0 50 100 150 200 250 300 350 400 450 0 200 400 600 800 1000 1200 10.2A 7.64A 5.06A 2.43A 10.2A 8.26A 6.03A 4.02A 1.98A 10.3A 9.15A 7.87A 6.59A 5.26A 2.63A 3.97A Input Voltage (V) No Shoot-through Time Shoot-through Time = 1us Shoot-through Time = 1.5us1.29A 0 50 100 150 200 250 300 350 400 450 0.70 0.75 0.80 0.85 0.90 0.95 1.00 No Shoot-through Time Shoot-through Time = 1us Shoot-through Time = 1.5us Input Voltage (V) Figure18.Wireless transferpower (a) andefficiency(b) characteristicsbasedontheq-Zsourcevoltage boostingmethodat20cmtransferdistance. 5.Conclusions Thispaperstudiesa3kWvehicle-mountedwirelesspower transfersystem. First, theefficiency of theLC-LCseries topologyisverifiedtobehigher thanthatof theLCL-LCLtopologywhentheir 322