Research on frequency stability of magnetic coupling wireless power transfer system

The natural oscillation frequency of the magnetic coupling wireless power transfer system is easily affected by circuit parameters and frequency bifurcation phenomenon often occurs. In order to solve the above problems, the equivalent circuit model of magnetic coupling wireless energy transfer system is used to derive the load resistance and transfer distance range that can maintain the frequency stability of the system. Furthermore, the load resistance range under which the system frequency stability is not affected by the transfer distance is obtained. In this range, the system always maintains a constant frequency and the natural oscillation frequency is not affected by the transfer distance. Moreover, the theoretical analysis is verified by simulation and experiment. The results show that the increase of load resistance and transfer distance will reduce the output power and transfer efficiency of the system to a certain extent. Therefore, in the context of maintaining the frequency stability of the system, the output power and transfer efficiency should be considered, and the appropriate load resistance and transfer distance should be selected so as to prevent the output power and transfer efficiency of the system from being too low.