Interoperability Analysis and Improvement for Rectangular Coil and DD Coil of Wireless EV Charging

Wireless charging technology for electric vehicles (EVs) has been investigated by lots of researchers. One of the key points of the technology is to ensure the interoperability between different vehicle assembly (VA) and ground assembly (GA). This paper describes the interoperability of different coils using coupling coefficient and efficiency by theoretical calculation, simulation and experiments. It is concluded that the interoperability between rectangular and DD coils is related to relative position of coils. Therefore, an adaptive position adjustment method using P&O algorithm and coupling coefficient estimation is proposed. By searching the optimal charging location, the output power and efficiency can be high when DD coil charges with rectangular coil. The experimental results agree with the theoretical analysis, which implies that the interoperability between two coils is improved by the proposed method.