A Solenoid Magnetic Coupler and Its Control Method for Omnidirectional Wireless Charging of UAVs

This article proposes a solenoid magnetic coupler for omnidirectional wireless charging of unmanned aerial vehicles (UAVs), which has a compact structure, high rotational and lateral misalignment tolerance, and low-leakage magnetic flux interference. The transmitter consists of two groups of orthogonal and mutually decoupled solenoid coils, which mainly generate horizontal (x-, y-direction) magnetic flux, and almost no vertical (z-direction) magnetic flux is generated. Hence, it can significantly reduce the leakage magnetic flux interference on UAV equipment. The solenoid receiver is attached to the UAV landing gear, which is lightweight and does not require additional installation space. To achieve maximum efficiency tracking under arbitrary angles and positions, a targeted omnidirectional wireless power transfer (WPT) method consisting of mutual inductance identification, phase difference configuration, and duty cycle optimization is presented. The experimental results show that the system output power and efficiency are maintained at 130–176 W and 84.1%–86.1% under arbitrary rotational and lateral misalignments.