Analytically Optimized Asymmetric Coupler Design for Wireless Drone Charging with Receiver-side Weight Constraint

This paper presents an analytical design optimization of an asymmetric coupler based inductive wireless drone charging system with a receiver-side weight constraint arising from the payload limit of the drone. To avoid time-consuming finite element analysis, the geometrical parameters of the circular planar coils are analytically designed to maximize coil-to-coil efficiency while achieving the target mutual inductance between the coils and adhering to a maximum allowed weight on the receiver side. The proposed analytical optimization shows that an asymmetric coupler results in an enhanced coil-to-coil efficiency compared to the conventional symmetric coupler while also reducing the weight of the receiver coil. A 85-kHz 4.5-cm air-gap 100-W experimental prototype of a wireless drone charging system having the proposed asymmetric coupler is built and tested. The prototype achieves a coil-to-coil efficiency of 91.3% while limiting the receiver coil weight below the drone’s payload limit. Furthermore, the proposed efficiency benefit is experimentally validated by comparing the performance of this asymmetric coupler based prototype with that comprising a symmetric coupler for the same system specifications.