A Full State Feedback Controller for Dynamic Capacitive Wireless Power Transfer Systems

This digest presents a novel full-state feedback (FSF) controller for compensating changing coupling variations in dynamic capacitive wireless power transfer (WPT) systems utilizing an active variable reactance (AVR) rectifier. The AVR rectifier enables continuous compensation, allowing the WPT system to maintain high-efficiency power transfer at a fixed frequency by appropriately distributing power between its two branches. Conventional PID control is suboptimal for the AVR rectifier due to the higher-order system dynamics, nonlinearities, and cross-coupling between control loops. In contrast, the FSF control strategy presents an optimal and robust way to control higher order multi-input multi-output systems like the AVR rectifier. A state-space model is developed for the AVR rectifier, and the FSF controller is designed based on this model. To validate the proposed approach, a 13.56 MHz 25-W capacitive WPT system with an AVR rectifier is built and tested. The controller’s effectiveness is demonstrated through both simulations and experiments on the hardware prototype.