Optimal Design of Fully Integrated Magnetic Structure for Wireless Charging of Electric Vehicles

Optimal design of a fully integrated magnetic structure for electric vehicle (EV) wireless charging is proposed in this article. The proposed approach helps save ferrite material, reduce the implementation cost, shrink the size of the converter, and improve the cost and power density. Typically, in a wireless charging system, an LCC resonant network and the receiver dc–dc converter are used, which require a bulky inductor in their structures. The integration of resonant inductor with the transmitter-side coil has been studied in the literature to reduce the overall cost and improve the power density of an EV wireless charger. The integration of the dc–dc inductor with the vehicle-side receiver coil is also introduced in the literature. However, the full integration of both resonant inductor and dc–dc inductor into the transmitter and receiver coils of the wireless charging system creates new design challenges that have not been addressed before. In this article, the proposed fully integrated magnetic structure and its design challenges are studied in detail. A procedure for achieving the optimal design of the fully integrated structure is presented. An optimization problem is defined to design the best magnetic structure and select the best values for the resonant elements and dc–dc inductor. The outcome of this integration is an all-integrated magnetic structure, compact converter, and efficient wireless charger. A 2.2-kW/85-kHz system is built to verify the feasibility of the proposed integrated wireless charging system, and its performance is evaluated through the experiment.