Misalignment Tolerance and Interoperability of Wireless Charging System Based on Two-Channel Topology and Coil Optimization

Inductive power transfer (IPT), as a method of wireless power transfer (WPT) via magnetic induction, can be applied to electric vehicles (EVs) due to its convenience and automation. Interoperability and misalignment tolerance are both major research difficulties for WPT of EVs. This paper proposes a two-channel topology and a coil optimization method, which can improve misalignment tolerance for the unipolar coil (Q) and interoperate with the bipolar coil (DD). Firstly, a topology with phase shift strategy is constructed to increase output ability with Y misalignments and the mathematical model of the proposed topology is established. Secondly, a coil density optimization method is presented to smooth the transmitting mutual inductances fluctuation. Finally, a 1-kW prototype is built to verify the proposed system which can achieve load-independent constant-current charging. With the Y misalignment of 150 mm, the experimental results agree well with the theoretical analysis. The proposed system is able to interoperate with two types of coils and can achieve misalignment tolerance.