Constant Current Output Control Based on Cross-Coupling Compensation in Multireceiver WPT System Using Active Rectifier

Multireceiver wireless power transfer (multi-Rx WPT) technology is a promising method for charging multiple electronic devices simultaneously. However, the cross-coupling effect between Rxs not only leads to the correlation of output characteristics of each load, but also reduces the power transfer capability and efficiency of WPT systems. This article proposes a method to achieve constant current (CC) output with cross-coupling compensation in multi-Rx WPT systems, thus avoiding tedious parameter measurement and communication between Rxs. The cross-coupling can be compensated adaptively, and the output can be controlled independently and not affected by the fluctuation of system parameters. A closed-loop control strategy based on the phase shift control method of an active rectifier is carried out, which can continuously regulate the load current while maintaining cross-coupling compensation. An optimized phase synchronization auxiliary circuit for multi-Rx WPT systems is presented, which shares the power transfer coils and is not affected by the cross-coupling effect. A 70-W two-load experimental prototype is built to verify the theoretical analysis, and the maximum efficiency reaches 88.1%.