Theorization of a Compatible Method for Far-field Leakage Magnetic Field Reduction and High Efficiency Power Transfer Using Adjacent Transfer Coil in Dynamic Wireless Power Transfer

In order to put dynamic wireless power transfer into practical use, it is necessary to reduce the leakage magnetic field, which has adverse effects on the human body and electronic devices, below the regulated value. At the same time, it is necessary to achieve high efficiency power transfer to utilize energy effectively. In this paper, the far-field leakage magnetic field at 10 m from the reference is reduced below the regulated value without adding any devices that are not necessary for power transfer by setting the input voltage to the adjacent transfer coil in the direction of the electric vehicle to be appropriate for the transfer coil that is supplying power. It is shown that the power transfer efficiency, including adjacent transfer coils, can be increased to more than 95 % without any additional equipment that is not required. This method is applicable to the case where S-S, Double-LCC, or LCC-S is used as the resonance method of the circuit, and the leakage magnetic field can be reduced to a maximum of 0.7 mA/m or less with 20 kW of receiving power in any resonance method. The effectiveness of this method is confirmed by theoretical calculations and electromagnetic field analysis using the method of moments.