Multiple-Receiver Inductive Power Transfer System Based on Multiple-Coil Power Relay Module

Abstract

Due to the compatibility considerations, it is not attractive for the commercial wireless charger to modify the Qi-standard coils for charging multiple loads. This paper would explore the potential of a power relay module (PX) to address this issue. The multiple-coil PX would enhance the effective coupling when the standard coupler fails. In this paper, different types of PXs are developed for various applications, including a two-coil PX using series compensation, a two-coil PX using high-order compensation, and a three-coil PX using high-order compensation. Their power and efficiency characteristics are analyzed in a uniform manner, and the benefits of different PXs are justified through a planar charger and a bowl-shape charger in the experiment. The implemented bowl-shape charger is able to offer one fast-charging channel for a single device (30 W) and one multiple-load channel for at most four devices (each 10 W) simultaneously. The peak efficiency is 88% when the overall delivered power of PX is 70W.