Compensation Parameter Optimization of Inductive Wireless Power Transfer System for Low Stray Magnetic Field

During the operation of an unmanned aerial vehicle (UAV) inductive wireless power transfer (IPT) system, stray magnetic fields from the magnetic coupler can compromise the safety of the UAV's electronic equipment. This issue limits the widespread adoption of the parallel coupler, despite its high coupling coefficient. This article proposes an improved design that allows designers achieve a lower magnetic field distribution in a parallel coupler without compromising its transfer power, which offers a balanced approach to optimizing the trade-off between high coupling coefficient and low stray magnetic field distribution in couplers for UAV-IPT. Specifically, the magnetic field generated by the transmitter coil and receiver coil is analytically studied, and an improved compensation parameter design is presented to achieve a lower magnetic field distribution. Besides, it also compares the stray magnetic field distribution characteristics of the improved design described in this article with that of the conventional design widely used for the parallel coupler. Finally, a system is implemented to verify the low stray magnetic field distribution characteristics. The experimental results show that the improved design reduces the stray magnetic field around the UAV's electronic equipment by 40.3% compared to the conventional design, while maintaining the same transfer power.