Design of an on-board charger for universal inductive charging in electric vehicles

Inductive Power Transfer (IPT) technology is a potential solution in battery charging of electrical vehicles (EV). However, problems of varied magnetic coupling caused by coil misalignment still limit its practical applications. Besides improvements of inductive chargers, the EV manufacturers need a standard on the power-receiving part for adaptive charging in various conditions. Accordingly, this paper proposes design of an on-board charger, which cooperates with the previously proposed universal inductive charger (UIC), for more universal, efficient and safe EV charging in various coupling and load conditions. The optimal design of the secondary LC circuit and the receiving pad is provided. A simple and low-cost control method based on the dual-mode operation of the DC-DC converter is applied, to coordinate with the UIC for more accurate control on the frequency and voltage. Simulation results and a prototype validate the proposed on-board charger is robust and applicable, and performs better for universal inductive charging.