Design of a Magnetic Coupler for Wireless Power Transfer Systems With High Rotational Misalignment Tolerance Based on Rotating Magnetic Flux

Misalignment tolerance is a critical factor impacting the practical application of wireless power transfer (WPT) systems. This article proposes a novel coupler design that significantly enhances the stability of the output voltage against angular misalignment. The proposed coupler utilizes a rotating magnetic field to provide omnidirectional coupling flux in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xoy</i> plane for the bipolar receiver. The key structural parameters of the novel coupler are optimized via the finite-element analysis to achieve a high coupling coefficient, strong misalignment tolerance, and low cross-coupling mutual inductance. To mitigate cross-coupling effects, a series capacitor compensation method is implemented in the multi-transmitter system. A 320 W prototype is finally developed, which employs an LCC-S compensation topology to further improve the system’s misalignment tolerance and achieves a DC-DC efficiency of 91.54%. Without additional voltage control, the output voltage fluctuation remains below 5% even under a 360° angular misalignment in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xoy</i> plane.