Analysis and comparison of two wireless battery charger arrangements for electric vehicles

The paper deals with wireless battery chargers (WBCs) for plug-in electric vehicles (PEVs) and analyzes two arrangements for the receiver of a series-series resonant WBC. The first arrangement charges the PEV battery in a straightforward manner through a diode rectifier. The second arrangement charges the PEV battery through the cascade of a diode rectifier and a chopper whose input voltage is kept constant. Figures of merit of WBCs such as efficiency and sizing factor of both the power source and the transmitter/receiver coils are determined. Afterwards, they are discussed and compared with reference to the case study of WBC for an electric city car. A proposal to optimize the efficiency of the second arrangement by a suitable selection of the chopper input voltage is presented. Measurements on the efficiency of the two arrangements are included to support the theoretical results.