High-Power Wireless Power Transfer of Drones with Wide Charging Area

Abstract

This study investigates high-power wireless power transfer(WPT) with a wide charging area for large drones. The overall size of the receiving coil(Rx-coil) connected to the leg of the drone on the bottom side is 420×420×10 mm. Transmitting coils(Tx-coils) of three different shapes are individually optimized and combined to achieve a uniform magnetic field intensity and high power transfer efficiency(PTE) retention rate. The overall dimension of %the Tx-coil including the case thickness is 1,000×1,000×105 mm. The quality factors of the optimized Tx-and Rx-coils are 120 and 54, respectively, expressing a high PTE according to the transmission and misalignment distances. Based on the center between the coils, the PTE is 91 % and 80 % at a transmission distance of 50 mm and 300 mm, respectively. The PTE is 89.5 % when the Rx-coils are positioned at a misalignment distance of 285 mm, which indicates the edge of the Tx-coil in the charging area. The coils are connected to various equipment(e.g., signal source, Tx-and Rx-modules, load, etc.) to verify the WPT system. The system efficiency considering loss is 69 % because the input and output powers are 174.7 W and 120.3 W, respectively. In addition, an electromagnetic wave is measured below the electromagnetic interference standard.