Design and Optimization of a Reconfigurable Powertrain-Integrated IPT Receiver for UAS Wireless Charging

Wireless charging of unmanned aerial systems can extend flight time by enabling fully autonomous and interoperable charging. However, this necessitates integrating a receiver coil and the associated power electronics into the drone, increasing cost and weight. This work addresses this challenge by proposing an integrated wireless charger that repurposes existing powertrain components of a hybrid VTOL fixed-wing drone, such as the drive inverter and motor, to function as a wireless receiver. Feasible topologies and reconfiguration methods are reviewed. Motor performances during charging are analyzed, and an optimization framework is developed to identify optimal operating conditions for the inverter and motor, both susceptible to high-frequency losses in charging mode. Additionally, the proposed powertrain-integrated receiver enables control of battery charging directly on the drone, eliminating the need for transmitter-side charging control and communication. Targeting maximum gravimetric power density γ and DC-DC efficiency η, the algorithm converged to a Pareto front. An optimum design was prototyped and experimentally validated by coupling a 1.73-kW wireless charging system with a ≈4.4-kW drone powertrain. The results demonstrate a power density γ of 3.71 W/g and peak charging efficiency η of 88.5% to 90%, depending on the selected motor, at a vertical charging distance of 45 mm.