Primary Side Clamp‐Assisted IPT Charging System With Self‐Sustaining Constant Voltage Limitation and Secondary Lightweight Design

Inductive power transfer (IPT) systems are suitable for battery charging due to the advantages of safety and convenience. Besides, battery charging requires constant current (CC) and constant voltage (CV) output characteristics. However, existing methods for achieving CC‐CV output have problems such as complex control, poor reliability, and unnecessary cross‐coupling. Therefore, in order to solve the above problems, this article proposes a primary side clamp assisted IPT charging system with inherent CC to CV output and secondary lightweight design, which adopts inductor‐capacitor‐capacitor compensated primary coil, series compensated clamp coil, and series compensated secondary coil. The proposed system can achieve automatic conversion from CC output to CV output through primary side clamping and reasonable parameter design, without the need for additional DC‐DC converters and complex control strategies. In addition, the system utilizes two independent and mutually perpendicular solenoid coils as the primary coil and the clamping coil. The mutually perpendicular solenoid coils are naturally decoupled, eliminating the influence of unnecessary cross‐coupling on the system output characteristics. First, the decoupling characteristics of the proposed magnetic coupler are analyzed in detail theoretically. Second, a mathematical model is established to analyze the load‐independent CC and CV output characteristics and ZPA operation. Finally, an experimental prototype with CC output of 4 A and CV output of 72 V is built to verify the correctness of the theoretical analysis.