Transmitter with cooperative coils matrix for robust wireless power transfer system

Wireless power transfer (WPT) system is to provide power transmission via near field magnetic resonant coupling between the transmitter and the receiver with the same frequency. In WPT system the most important parameter is efficiency. This paper proposes different cooperative transmitter matrixes with multiple coils. This design enables receiver coil to be freely placed and charged above the wireless charging pad which can select several coils on and other coils off according to the location of the mobile device. The optimal radius of the coil is determined for different transmitter matrixes based on the field forming. Then the 9 coils transmitter matrix is adopted with the higher efficiency expense ratio in the effective charging area. Simulation results show that the proposed system achieves efficiency above 60% for a receiver placed 10 cm away from the transmitter.