Objective As human exploration of marine resources deepens, underwater mobile devices play an increasingly critical role. However, their endurance in deep-sea operations is severely limited by the inflexibility and inefficiency of conventional power supply methods. Undersea wireless power transfer (UWPT) technology enables autonomous recharging, effectively extending the operational endurance of these devices.

Method This study designs a high-efficiency, misalignment-tolerant UWPT system for autonomous underwater vehicles that achieves controllable power transfer. First, a DC-DC power interface unit for the subsea environment was designed based on an LLC resonant converter, with an in-depth analysis of the impacts of varying load resistance and magnetizing inductance on its performance. Second, to enhance the energy transfer efficiency, a system integrated with an LCC-S compensation network was proposed. By applying optimal mutual inductance theory, the main circuit parameters and the coupling mechanism were designed to achieve the optimal electrical configuration for maximum energy transfer efficiency.

Result A 1.5 kW prototype of the undersea DC-DC power interface and wireless charging station was built and tested under a 1 kV input condition. The system achieved an overall end-to-end power transfer efficiency of 90.82%.

Conclusion The experimental results not only validate the accuracy of the theoretical analysis and calculations but also confirm the practical feasibility of the proposed UWPT system, which is based on the designed undersea DC-DC power interface.