Magnetic field analysis of coils in wireless charging systems

Abstract

To enhance the uniformity of magnetic field distribution in highly flexible wireless power transfer (WPT) systems, this research proposes a novel optimization technique leveraging a multi-coil matrix for improved field control. A three-dimensional analytical magnetic field model was established in a planar two-dimensional space and extended to a multi-turn, multi-coil matrix topology. The composite magnetic field superposition equation was derived to characterize field interactions. Finite element analysis revealed the effects of coil spacing, vertical spacing, and inner spacing on field uniformity, with Analysis of Variance (ANOVA) quantifying parameter sensitivity. Results indicate that the spacing-to-wire-diameter ratio critically impacts uniformity. The proposed optimization scheme achieved a 37.27% improvement in the B-field uniformity index and an 88.18% enhancement in average flux density within the target area, compared to the baseline configuration. This study provides theoretical foundations and an engineering implementation framework for constructing high-stability wireless power supply systems, demonstrating significant application value.