Proposal of Sensorless Vehicle Detection Method for Start-up Current Control in Dynamic Wireless Power Transfer System

This paper discusses the start-up process for a dynamic wireless power transfer system to an electric vehicle passing a road-side coil. To transfer maximum energy in a short time, the process of detecting an approaching vehicle and transmitting power must be carried out quickly. In most of the previous studies, problems of vehicle detection and power transmission have been considered separately. In this paper, the power transmission control process is proposed that combines vehicle detection and current control. The detection process uses only vehicle-side voltage pulse which enables both road-side and vehicle-side coils to sense approaching of the vehicle-side coil. And the current control suppresses the current overshoot at the start of power transmission. The proposed method was verified by experiments. Both coils could detect another one at a sufficient distance from each other. Additionally, power transmission starts at a point of small coupling coefficient was achieved without current overshoot.