Proposal of Coil Embedding Method in Asphalt Road Surface for Dynamic Wireless Power Transfer

Transmitter coils used in dynamic wireless power transfer are embedded in the road, so it is important to improve the power transmission performance of the coils as well as the strength and durability of the pavement. This study proposes a method of embedding the coils in the surface course near the road surface. To compare the electrical characteristics of the proposed method with the conventional method in which the coil is embedded inside the asphalt pavement at a depth of 50 mm from the road surface. In addition, a comparison of case-less coils, hard plastic coil cases, and soft rubber coil cases was conducted to select coils suitable for embedment near the road surface. The results of coil embedment experiments on a road designed for a national highway showed that all coils could achieve more than 54 kW of power at an efficiency of 95% at a transmission distance of 200 mm and a 600 V equivalent value in the power transmission evaluation by VNA (Vector Network Analyzer). In addition, the results of pavement strength tests showed that surface embedment tended to have higher pavement strength than embedment at a depth of 50 mm from the road surface.