Crossed flat solenoid coupler for stationary electric vehicle wireless charging featuring high misalignment tolerance

Abstract

This study proposes a crossed flat solenoid coupler (CFSC) for electric vehicle wireless charging. The impact of four size parameters of CFSCs on coupling coefficient and misalignment tolerance is studied using finite‐element analysis. The optimisation methodology of CFSCs considering size constraints is given. The CFSC is compared with the planar square coupler (PSC) and double D coupler (DDC) from three aspects: coupling coefficient, misalignment tolerance, and copper usage. The CFSC performs the best in the three aspects, and the DDC performs the worst. Two wireless power transfer prototypes, one employing CFSCs and the other utilising PSCs, were built to demonstrate the superiority of the proposed coupler. Primary inductor‐capacitor‐capacitor secondary series compensation topologies were employed in the two prototypes. Experiments agree well with theoretical analysis and simulations. The power transfer efficiency of the CFSC‐based prototype was 1.6% higher than the PSC‐based prototype when the Z‐axis displacement is 45 mm.