Influence factors analysis and improvement method on efficiency of wireless power transfer via coupled magnetic resonance

Wireless power transfer via coupled magnetic resonance has many merits, which has become one of the hot research spots in recent years. The progress of technology in the field of wireless power transfer is remarkable, but its power and efficiency vary with the impacts of the distance, orientation, and center deviation on transmission. To suppress the fast decrease of the transfer efficiency, the equivalent circuit model of wireless power transfer and mutual inductance theory were presented. The results provided critical insight into the design of improving efficiency using a novel method of frequency tracking. The measurement results showed that the efficiency decreased greatly with the distance, orientation and center deviation at fixed-resonance frequency, and the efficiency decreased slowly using adapted resonance frequency. The proposed method is proved through the experiment, and it can provide an effective way to improve the power and efficiency of wireless power transfer.