Voltage/Current Doubler Converter for Electric Vehicle Wireless Charging Employing Bipolar Pads

Abstract

Light-duty electric vehicles (EVs) typically have a rated voltage of either 400V or 800V. Especially when considering public parking infrastructures or owners with multiple EVs, e.g., car rental companies, EV wireless chargers must efficiently deliver electric power to both battery options. For this purpose, this paper proposes an advanced and compact version of the previously defined voltage/current doubler (V/I-D) converter, here comprising two coupled series-compensated bipolar pads (BPPs). The presented system can efficiently charge EVs with both battery voltage classes at the same power level without affecting the current rating of the converter’s circuit components. The control scheme is implemented at the power source side in terms of switching frequency and input voltage, and only passive semiconductor devices are employed on board the EV. The equivalent circuit is analyzed, focusing on the BPPs’ undesired cross-coupling and its effect on the power transfer. Methods to compensate for the cross-coupling are proposed regarding the BPP design and operating strategy. At 7.2kW and aligned BPPs, the DC-to-DC efficiency of 96.34% and 96.53% have been measured at 400V and 800V, respectively. The proposed method has been experimentally validated at different misalignment profiles while considering battery voltages 300V-400V and 600V-800V, which proves that the V/I-D converter is a universal charging solution for EV batteries.