An Active-Rectification Based Communication Free Inductive Power Transfer for Battery Charging System with Soft-Switching Capability

Inductive Power transfer (IPT) is rapidly developed for power conversion to batteries because of its high convenience, high safety and low operation cost. However, the output regulation of IPT system is of great complexity with maintaining soft-switching operation by conventional methods. In this paper, an inductive power transfer system for battery charging applications are proposed to achieve output regulation by only secondary-side control without the wireless communication. Besides, the proposed system can realize soft-switching on the primary-side to further reduce the power loss and the EMI issues. The system operates at a constant switching frequency and by a monotonic output regulation to maintain a high stability during the power conversion. The circuit operation analysis, proposed output regulation method and the hardware implementation are analyzed. In order to verify the proposed system, a 1 kW IPT prototype is built and its peak efficiency achieve 96.8% at 330 V/ 3 A output.