Adaptive Decoupling Between Receivers of Multireceiver Wireless Power Transfer System Using Variable Switched Capacitor

Simultaneously charging multiple devices is a unique advantage of wireless power transfer (WPT). However, it is challenging to analyze and optimize the performance of a multireceiver (multi-Rx) WPT system due to the intricate coupling among coils. In this article, a method for adaptive decoupling between Rxs is proposed for electronic device charging, which can achieve independent regulation of each output in a multi-Rx WPT system. A simple feedback control avoids tedious system structure and position parameters’ measurement and calculation. With a fixed driving frequency, the number of Rx is not limited. It is analyzed that the quadrature phenomenon of the transmitter (Tx) and Rx currents can be used as a sign that the cross-coupling is fully compensated. A phase synchronization channel is established that shares power transfer coils. An microprogrammed control unit-(MCU) free feedback loop is constructed in Rx to control the variable switched capacitor and finally realize adaptive cross-coupling compensation. A two-load experimental prototype was built to verify the theoretical analysis. Compared with the system without adaptive decoupling between Rxs, the measured system efficiency and output power of the proposed system were improved by 69% and 14.3 times, respectively.