Tuning of mid-range wireless power transfer system based on delay-iteration method

The practical mid-range wireless power transfer (WPT) system with high-quality resonant tanks is detuned easily due to the variation in parameters of the resonant tanks, leading to degradation of power transfer capability. For this reason, the frequency variation of the mid-range serial-serial (SS) topology WPT system under the condition of self-oscillation is analysed based on Hamel locus approach, considering the delays in devices. The delay-iteration method (DIM) to tune the transmitter (TX) is presented here. Use of this method can keep the overall TX delay equal to the self-oscillating cycle and the TX in the zero voltage switching state. When the DIM is applied, the disturbance observation method can be used to tune the capacitor of the TX, with no communication between the TX and the receiver. The experiment results validate the accuracy and stability of tuning mid-range loose-coupling WPT system using the proposed method.