Comprehensive research on the wireless power transfer technology of autonomous underwater vehicles is necessary to address the issue of significant energy loss in such vehicles during wireless power transfer. Previous analysis on factors that affect wireless power transfer in seawater environment demonstrated that the eddy current loss generated during transmission and offset of the coupling mechanism are the main factors that degrade the efficiency. In this study, existing literature on wireless power transfer for autonomous underwater vehicles in recent years is reviewed, and it is concluded that the energy loss during underwater wireless power transfer can be effectively reduced through coupling mechanism optimization, adaptive control, and docking device design. This study analyses the challenges of low-loss wireless power transfer for autonomous underwater vehicles and the prospects for future development trends and research areas, providing a reference for realizing efficient and flexible energy supply for autonomous underwater vehicles.

No abstract

The existing wireless power transfer systems for autonomous underwater vehicles (AUVs) have problems due to long transmission distances and the unstable attitudes of AUVs, which result in poor system performance. To solve this problem, this paper proposes a lightweight universal variable ring-shaped magnetic coupler for the shape characteristics of AUVs and the charging platform environment. In particular, the size of the magnetic coupler transmitter can be varied according to the size of the AUV, resulting in a close fit between the magnetic coupler transmitter and receiver, reducing the transmission distance and fixing the AUV attitude. To achieve a lightweight receiver and reduce the burden on the AUV, the design is optimized in terms of both the system topology and the magnetic coupler structure. First, the LCC-S topology is used to reduce the number of components on the secondary side. Second, the use of a nanocrystalline ribbon as the core material effectively reduces the weight of the magnetic coupler receiver. Finally, a 300-W experimental platform is built to verify the functionality of the designed magnetic coupler.The experimental results show that the system has a DC-DC transfer efficiency of 86%. With the variable ring-shaped magnetic coupler, the charging power can be increased by 7.2% when the transmission efficiency remains unchanged.autonomous underwater vehicle (AUV), nanocrystalline ribbon, variable magnetic coupler, wireless power transfer (WPT) | INTRODUCTIONIn recent years, autonomous underwater vehicles (AUVs) have become a hot research topic in the field of marine engineering due to their significant applications. [1][2][3] Although AUVs have excellent maneuverability and flexibility, the limited energy of the batteries they carry does not allow them to perform continuous work over a long period of time and over a large area. [4][5][6] Wireless power transfer (WPT) is a new energy supply method that can compensate for these drawbacks and give AUVs a new level of performance. [7][8][9] WPT was first applied in the air medium, mainly for wireless charging of electric vehicles, 10 wireless charging of medical electronic pacemakers, 11 and wireless charging of smart tailless homes. 12 As the technology progresses and the