Characteristic of frequency in wireless power transfer system via magnetic resonance coupling

Aiming at the efficiency of wireless power transfer via magnetic resonance coupling varies according to the air gap between the transfer device and receiver device, a new analysis on characteristic of frequency was presented, which yielded critical insight into the design of practical systems, including the introduction of frequency splitting that could be used to compensate the efficiency with different distance and the maximum operation distance that could be used to improve power transfer distance. Equivalent circuit model was designed and the experiment results verify the correctness of key theoretical analysis on frequency splitting and the maximum operation distance(critical coupling point); thus it provides an effective reference for improving the power transfer efficiency and operation distance.