Optimal Design Method of Size-Adjustable Coil for Compensation of Lateral Misalignment in WPT Systems

This work demonstrates optimal design method of size-adjustable coil to compensate degradation of transfer efficiency due to lateral misalignment in two-coil magnetic resonance WPT systems at 6.78 MHz. Size-adjustable coil is designed by reducing the coil width from 100×100 mm
²
size and varying initial offset. Also, overall transfer efficiency is increased by winding turn of coils. The proposed method is replacing optimal coil pair when transfer efficiency of 100× 100 mm
²
size degrades due to misaligned between Tx and Rx coils. By replacing two different size of coil pair at a certain location, two types of transfer efficiency curves can be obtained. One is flat transfer efficiency which can maintain up to 90% efficiency until 75 mm lateral misalignment occurs. Another is high transfer efficiency compensation of null point which can compensate 92.4% efficiency and successfully remove null point. In results, over 70% of transfer efficiency region is compensated when lateral misalignment reaches 116 mm.