Performance of size-adjutable coils for compensation of lateral misalignment between coils in wireless power transfer systems based on magnetic resonance

Abstract

This work presents the estimated performance of a virtual resonant-type wireless power transfer system with size-adjustable coils to minimize the reduction of the transfer efficiency due to the lateral misalignment between the source and load coils. Experimental results for a 6.78 MHz system reveals that by reducing the size of the coil adaptively according to the misalignment, the transfer efficiency can be maintained above 80% even when effective overlapping area is reduced to 11.5% between a 20×20 cm2 coil pair that is placed 5 cm apart. Moreover, the proposed coil system successfully removes the transfer null caused by a large misalignment. Although the results provided are based on switching between coils with different sizes, experimental results for a single-coil system will be presented at the conference.