Analysis of Factors Effecting on Optimal Configuration of Two Receivers for a Three-Coil Wireless Power Transfer System

In this paper, we investigate the optimal configuration of receivers for a three-coil wireless power transfer system in which a transmitter is located between receivers. Based on an equivalent circuit model, we first find the compensatory reactance terms to eliminate cross coupling between receivers. Neglecting cross coupling, we derive an optimal coupling coefficient between a receiver and transmitter for a given arrangement of a second receiver, as a means of maximizing the transmission efficiency (TE). Using this theoretical analysis, it is revealed that the TE can be improved by locating the first receiver far from the transmitter when the first receiver has higher quality factor or the distance between the transmitter and the second receiver is lower. Results for various cases show that our analytical results are in a good agreement with experimental ones.