An On-Body RecCoil Array Harvester System for Extended Wireless Charging of Misaligned Quadcopters

In conventional unmanned aerial vehicle (UAV) wireless charging systems, the quadcopter must be perfectly aligned with the charging pad to ensure effective magnetic coupling for charging. To enhance quadcopter landing flexibility, the authors propose an innovative on-body RecCoil array harvester with a central receiver (Rx) coil to capture longitudinal field components and four auxiliary side Rx coils to encapsulate lateral field components, each formed by two oppositely wound circular coils and integrated with full-bridge rectifiers. The rectified outputs are combined using a DC technique. The Rx coil is EM-optimized to harness three orthogonal H-field components from the Tx coil, ensuring uniform voltage and Power Transfer Efficiency (PTE) across the Rx plane at a 50 mm altitude. Simulation results indicate that the lateral misalignment tolerance of the proposed structure decreases with increasing altitude beyond 50 mm. The design improves measured PTE to 72.22% (aligned) and 70.91% (misaligned), outperforming the conventional Rx coil’s PTE of 50.13% and 17.01%, respectively. Furthermore, it is seamlessly integrated with the PCB-based charging circuitry to validate and demonstrate the battery charging process effectively. Because it weighs 20 g lower than its competitors, its flying efficiency won’t be compromised, thereby providing a superb misalignment charging (offset between the Tx and Rx) of 100% at 50 mm for the quadcopter with good PTE, given the well-organized and optimized RecCoils to well-matched full AC-DC rectification. The dynamic tests for drone charging will be considered as a part of future works.