Single-Transmitter-Controlled Multiple-Channel Constant Current Outputs for In-Flight Wireless Charging of Drones

This article proposes a single-transmitter-controlled multiple-channel constant current outputs scheme, which can energize multiple hovering drones over the air simultaneously. As an unmanned and cost-effective solution to extend the cruising range of drones, the multiple-drone in-flight wireless charging has to deal with two key technical challenges, namely the continuous disturbance of multiple mutual inductances (M) caused by the hovering attitude of drones, as well as the limit of drone-side payload. Accordingly, this article adopts the multifrequency resonating compensation to establish multiple transmission channels and achieves the single-transmitter-controlled multiple-channel constant current outputs based on a communication-free multiple-M estimation method. The simulated and experimental results are both given in this article, which shows that the accuracy of the multiple-M estimation is up to 97% and the steady-state accuracy of the current output control is up to 95%. What is more, the current output control can effectively restrain the output current fluctuation of the battery load under continuous multiple-M disturbance, indicating that the proposed scheme is feasible to improve the stability and reliability of the multiple-drone in-flight wireless charging system.