A Topology Reconstruction Based WPT System with CC and CV Outputs Function

Constant current (CC) charging and constant voltage (CV) charging are the two main charging stages of lithium -ion batteries in wireless charging systems. The traditional LCC-LCC topology has a high degree of design freedom. The conversion from CC to CV output is usually achieved through composite topology or frequency switching, which results in high control complexity and increases system cost. This paper proposes a wireless power transfer (WPT) system with CC and CV output characteristics based on topology reconstruction. Based on the LCC-LCC topology, by introducing one MOSFET in the rectifier and one AC switch which consists of two MOSFETs connected in reverse series to reconfigure the topology, the conversion from CC to CV mode can be achieved without complicated control methods and additional components. In addition, the proposed system works at a fixed operating frequency point, which can effectively avoid frequency bifurcation phenomenon. Therefore, the proposed system features a simple structure, easy control, low cost, and high robustness. In addition, ZPA operation can be realized in both CC and CV modes, ensuring high transmission efficiency. An experimental prototype with a rated power of 480 W is built, and a maximum efficiency can reach 93.5%, which verifies the feasibility of the system.