A Wireless Charging System with Dual Switchable Constant Voltage and Constant Current Outputs Based on Intermediate Coils

Abstract

The charging process for lithium batteries in the field of wireless power transfer (WPT) for electric vehicles is mainly divided into constant voltage (CV) and constant current (CC) charging processes. In order to satisfy the dual CC and CV charging outputs using the same input in a limited space, this paper proposes a wireless charging system with dual switchable CC and CV outputs based on two intermediate coils. Unipolar and bipolar coils are utilized to achieve this goal. The mathematical model is developed to evaluate the CC and CV output characteristics. A simulation model is built in MATLAB/Simulink to confirm the effectiveness of the proposed method. The method in this paper has the advantage of simplicity and low cost by using only two relays to achieve simultaneous dual-port CC and CV outputs with a fixed operating frequency.