Flexible Combination and Switching Control for Robust Wireless Power Transfer System With Hexagonal Array Coil

Multitransmitter structure can improve the misalignment tolerance of wireless power transfer (WPT) system, but some new problems such as a sharp drop in transmission efficiency will occur when the receiver moves to the boundary situation between transmitters. It is very crucial to solve this problem for an efficient and stable WPT system. In this article, a flexible combination multitransmitter coupling structure based on hexagonal array coil and auxiliary switch is proposed, and the coupling characteristics under misalignment conditions has been deeply analyzed with mutual inductance model. Unlike using coupling coefficient, a convenient switching control strategy is proposed based on the primary current to activate the optimal coil working mode, and the experimental results favorably verified the theoretical analysis. Compared with the circular array coil and the square array coil, the proposed coupling structure and control method can greatly improve the transmission efficiency of the WPT system at the coil boundary, and has stronger robustness under different misalignment conditions.