Optimization of Mutual Inductance in Double-layer Overlapping EVCharging Systems Against Longitudinal Migration

This paper addresses the mutual inductance degradation caused by longitudinal displacement of the pickup coil in dynamic operation of double-layer overlapping wireless charging systems for electric vehicles, proposing an optimization scheme with embedded multi-stage rectangular compensation coils. Through COMSOL simulations for internal structural compensation of circular pickup coils and comparative topology optimization of multi-stage rectangular configurations, the four-stage rectangular coil was identified as the optimal compensation structure. To enhance mutual inductance stability and transmission efficiency, co-simulation using COMSOL and Matlab is conducted for multi-parameter optimization of the compensation coil turns. Experimental results demonstrate that under longitudinal offset conditions, the optimized embedded four-stage rectangular compensation coil can maintain system mutual inductance fluctuation within the range of –0.79% to 0.4%, while significantly improving overall system transmission efficiency.