Design and Analysis of Misalignment Insensitive Wireless Power Transfer System Based on Multitransmitter for Constant Power

This article proposes a multiple transmitting array wireless power transfer (MTA-WPT) system with constant output power charging for consumer electronics, such as tablets and mobile phones. Compared to conventional wireless power transfer (WPT) systems, this proposed system can achieve constant output power by controlling the current phase shift of the transmitting (Tx) coils when the receiving (Rx) coil is located at different positions and directions. The detailed circuit topology of the proposed system is modeled and analyzed to obtain the correspondence between the current phase shift and the load output power. Furthermore, the excitation current distribution strategies for a system of three and four Tx coils at optimized efficiency are theoretically analyzed. The simulation demonstrates that the proposed system can achieve constant output power with modulating the phase shift at various Rx sites. Finally, an experimental prototype with four Tx coils is designed and carried out to prove the effectiveness of the phase shift modulation method and current distribution strategy. Besides, the superiority of the proposed MTA-WPT system is verified by comparison with other methodologies. The experimental results show that the output power of Rx at different positions is kept at roughly 41 W with the transmission efficiency over 80% by the Tx current phase shift modulation.