Compact and Highly Efficient Coil Design Using a Repeater Coil in WPT System for BEV/PHEVs

Wireless power transfer (WPT) for BEV/PHEVs is being studied to improve user convenience and safety of charging. This paper presents a new WPT system for BEV/PHEVs that has a repeater mounted on the transmitter. The size of the repeater is adjusted according to vehicle height. By inserting a repeating coil between the transmitting and receiving coils, transmission efficiency is improved and the transmitting coil can be downsized. By theoretical analysis and electromagnetic field simulation, it is shown that insertion of a repeating coil is effective in reducing the size of the transmitting coil.