A Circumferential Coupled Dipole-Coil Magnetic Coupler for Autonomous Underwater Vehicles Wireless Charging Applications

Inductive power transfer is a practical approach to recharging the autonomous underwater vehicles (AUVs). The performance of the magnetic coupler determines the system transfer capacity. The annular magnetic coupler is widely utilized in the underwater wireless charging system. However, this magnetic coupler has limitations on magnetic field distribution. The flux linkage occupies the center of the AUV, and hence, the electronics inside the AUV are susceptible to electromagnetic interference. Additionally, the weight of the annular magnetic coupler greatly increases the burden on AUV power supply. In this paper, the magnetic coupler structure evolution is analyzed and a dipole-coil-based magnetic coupler with a novel circumferential coupling manner is presented. The magnetic flux is perfectly confined by the coupling manner, and the magnetic coupler weight is reduced by dimension optimization. To implement the magnetic coupler, the Fe-based nanocrystalline soft magnetic material is taken into consideration. To validate the proposal, a wireless charging system is built. Experimental results show that the system transfers 630W under water with a DC-DC efficiency of 89.7%.