Optimal System for a Free-Positioning Wireless Power Transmitter with Coils Arranged in a Square Pattern

This study introduces an optimal system combining a circuit configuration and control algorithm for wireless power transmitter with coils arranged in a square pattern. The system uses a four-leg half-bridge inverter to simultaneously feed power to four coils through a switch set. Inductances, including the mutual inductances between the transmitter coils, are eliminated using the reactance devices on the return path in the proposed circuit configuration. The proposed control algorithm enables uniform power transfer at maximum efficiency, independent of the receiver position. The experimental results obtained using a prototype of the transmitter confirm that the system can transfer 500 W with a slight variation of 5.56% and efficiencies more than 80.6%.