A communication-free WPT system based on transmitter-side hybrid topology switching for battery charging applications

A communication-free wireless power transfer system based on transmitter-side hybrid topology switching for various battery charging applications is proposed in this paper. The method realizes the stable and reliable constant current (CC) and constant voltage (CV) outputs by the inherent characteristics of the designed hybrid topology. Besides, the zero phase angle condition can be obtained, which enhances the power transmission capability and improves system efficiency. The transition point from the CC to CV charging mode is determined by the battery charging voltage, which is estimated in real-time by measuring the root-mean-square value of high-frequency inverter output current. Then, the whole charging process can be operated by the transmitter-side controller; hence, the receiver-side controller is unnecessary. The advantages are that wireless communication links for real-time feedback of charging parameters between the transmitter and receiver are avoided, sophisticated control strategies are no longer required, and a lightweight, miniaturized, and compact receiver is guaranteed. Finally, to verify the effectiveness and practicability of the proposed approach, a confirmatory experimental setup with 80 V charging voltage and 5 A charging current is constructed. The experimental results match the theoretical analysis.