Power control study of dynamic wireless charging system based on resonant point switching

Aiming at the problem of power fluctuation during the movement of the receiving coil in the current segmented dynamic wireless charging (DWC) system, a power control strategy for DWC systems based on resonant point switching is proposed. By controlling the operating frequency of the inverter power supply so that the system works at the second resonant point, the output power is decoupled from the mutual inductance of the coil under the condition that the receiver side moves, eliminating the need for double-ended communication. In this paper, the general mathematical model of the DWC system is established, and the general parameter conditions for realizing the zero-phase operation of the system are analyzed. It is found that there are two second resonance points on both sides of the main resonance point under the over-coupling condition. Furthermore, the energy transfer characteristics of the system under different resonance points are analyzed, and the characteristics that the second resonance point can achieve constant power are verified. Finally, the constant power characteristics of the DWC system at the second resonant point under the moving condition of the receiver are verified by simulation and experiment.