CC/CV Self-Switching Inductive Power Transfer System for Battery Wireless Charging Based on Hybrid Compensation Topology

Inductive power transfer (IPT) is widely used in wireless charging of batteries, and in order to meet the demand of constant current (CC) and then constant voltage (CV) charging, an IPT system with CC/CV self-switching output characteristics was proposed. The system adopts a hybrid compensation topology, and the dual receiving coils were decoupled by the decoupling capacitor. First, the principle of the decoupling capacitor and the hybrid compensation topology output characteristics were analyzed, and their parameters were designed. The magnetic coupler has a circular and square structure with a center-symmetric structure for rotating applications, whose parameters are optimally designed to realize the proportional change of mutual inductance with horizontal misalignment. Therefore, the CC/CV load switching point remains unchanged when the magnetic coupler is misaligned. Finally, a 270-W IPT system prototype was built to demonstrate the CC/CV self-switching characteristics of the proposed IPT system. The CC and CV output fluctuations are 8.7% and 5.0%, respectively, and the system efficiency is up to 94.68%.