Three‐Zone Nonuniform Coil Geometry for Magnetic‐Field Uniformity and Robust Foreign‐Object Detection in EV Wireless Power Transfer

ABSTRACT Foreign object detection (FOD) is a critical safety function in electric vehicle (EV) wireless power transfer systems. Recent studies have primarily focused on detection algorithms and sensing‐coil design; although these approaches improve sensitivity, they still face challenges from power‐channel interference, limited receiver‐side misalignment tolerance, and residual detection blind zones. To address these challenges, this paper develops a comprehensive methodology for transmitter coil modeling, simulation, and magnetic field uniformity design. The magnetic field distribution at arbitrary spatial points is analytically modeled and simulated, and a three‐zone nonuniform winding scheme is introduced to improve field uniformity without degrading transfer capability. On this basis, symmetric sensing coils and a sequential scanning architecture are implemented, together with a voltage–phase joint decision mechanism, to achieve full‐area coverage and robust discrimination. Experimental validation on a 7.7‐kW prototype developed following the SAE J2954 design guidelines demonstrates that the proposed method improves magnetic‐field uniformity by 54%, reduces the maximum detection‐voltage difference from 9.2 to 3.36 V, and reliably distinguishes metallic from biological foreign objects, while maintaining stable performance under receiver‐coil misalignment. These results confirm the effectiveness of co‐designing magnetic field optimization and detection strategy to enhance the safety and reliability of EV wireless charging systems.