Frequency offset suppression method for wireless power transfer based on nonlinear resonant network

In magnetically resonant wireless power transfer (MR-WPT) systems, transmitter, and receiver usually operate at the same resonant frequency. However, parameters of inductor, capacitor, or other components are susceptible to changes due to environmental factors and cause resonant frequency deviation. This would lead to decrease of transmission performance. To solve the problem, a wireless power transfer system based on a nonlinear compensation network is proposed to suppress frequency offset. The modeling of the nonlinear MR-WPT system is first established. On this basis, the mathematical equation of the equivalent nonlinear circuit is deduced and the amplitude-frequency response characteristics are analyzed. The influence of inductance parameter on the nonlinear characteristic is studied. Furthermore, the effects of excitation amplitude, compensation capacitance, load, and magnetic ring turns on the operating characteristics of the nonlinear resonant circuit are analyzed. The proposed nonlinear resonant wireless power transfer system is constructed and is experimentally studied. Compared with the traditional linear MR-WPT system, the results show that frequency offset can be effectively suppressed, which ensures efficient transmission performance with the proposed method.