Novel Self-Resonant Multilayer Onboard Coil for 85 kHz Wireless Power Transfer

In recent years, research on wireless power transfer has grown, especially for dynamic wireless power transfer (DWPT) systems for electric vehicles. One of the current issues is that resonant capacitors on the vehicle make installation more difficult. One solution is the use of open coils that do not require a resonant capacitor but instead self-resonate with parasitic capacitance. However, limited research exists on open coils that meet the international standard of 85 kHz for DWPT. This paper proposes a new multilayer design for open-type edgewise coils that can self-resonate at 85 kHz band. This new approach enables resonance in the 85 kHz band with less than one-third of the number of coil turns compared to the conventional method addressing issues such as efficiency and manufacturing costs. The proposed design was validated through both electromagnetic field analysis and experimental measurements. The results demonstrated consistent trends between the simulation and experiments, confirming the feasibility and practical potential of the proposed method.