Design and optimization of a five-coil wireless power transfer system

Abstract This paper investigates the parameters of a multi-relay wireless power transfer system integrated with insulators in high-voltage transmission lines. Considering the spatial constraints of transmission lines, an equidistant distribution structure based on four-layer stacked coils is proposed. Given the system’s operation at high frequencies, the coils are significantly affected by skin and proximity effects. By exploring the suppression mechanism of wire spacing on proximity effects, the coupling relationship between coil parasitic resistance, wire spacing, and frequency is simplified. Utilizing polynomial regression, a frequency response function for coil resistance is established, linking system transmission efficiency with frequency. Aiming to maximize transmission efficiency within the 200 kHz to 800 kHz range, frequency scanning with 1 kHz steps identifies the optimal operating frequency. Finally, a five-coil experimental prototype validates the theoretical analysis, and the causes of discrepancies between theoretical and experimental results are analyzed.