Adaptive Frequency Tracking Control with Fuzzy PI Compound Controller for Magnetically Coupled Resonant Wireless Power Transfer

In the magnetically coupled resonant wireless power transfer (MCR-WPT) system, parameter variations of the resonant network will cause the resonant frequency drift, which will make the system in the detuning state. The detuning will increase the required capacity of the power supply and reduce the transfer efficiency of the system. To solve this problem, this paper analyzes the relation between the input impedance angle of the primary side and the resonant state and proposes an adaptive frequency tracking control (AFTC) method based on the fuzzy PI compound controller. In this method, a fuzzy PI compound controller is used to control the impedance angle (θ = 0), which can make the operating frequency to track the resonant frequency, so that the MCR-WPT system can maintain in the resonant state. The experimental results show that the AFTC method can make the operating frequency to track the resonant frequency faster and accurately during the parameter variations so that the MCR-WPT system can maintain in the resonant state and achieve the higher output power and system efficiency.