Efficiency improvement for multi-position of receiver in 13.56 MHz wireless power transfer coupling system

In the dynamic wireless charging for electric vehicle (EV), the relative position of energy transmitter and receiver depends on the movement of EV. Therefore the average efficiency is low in charging area when the EV runs away from the optimized position of the transfer system. In this paper, the solution to improve the efficiency due to the variation of charging position is proposed. The coupling system is strongly coupled magnetic resonance (SCMR) technology. The impedance is dynamically matched in the transmitter to improve the transfer efficiency. In the simulation, the 91.2% highest efficiency at 55 cm is designed and it is improved maximum 56.4% within 55 cm transfer distance and 40 cm misalignment with the proposed solution. Moreover, the experimental system can automatically improve the efficiency depending on the position of receiver and lookup data.