This article presents a novel design approach for a six-plate horizontal coupler for underwater capacitive power transfer (CPT). The coupler comprises four power transfer plates and two shielding plates that effectively prevent external interference and reduce its potential as an interference source. Unlike prior six-plate CPT coupler designs, this approach employs different dielectric materials between the plates. Specifically, water acts as the dielectric between the transmitting/receiving side plates, whereas air is used between the same-side power transfer plates and shielding plates. This selection of materials significantly reduces the ratio of self-capacitance to mutual capacitance due to the high permittivity of water as compared to air. Consequently, the coupling coefficient of the six-plate coupler is enhanced, leading to increased efficiency while maintaining electric field shielding. Experimental results from a 5-kW prototype with 200-mm side length plates and 10-mm air layer thickness demonstrated a dc–dc efficiency of 87.2% over a 60 mm distance in freshwater testing. Additionally, the coupler demonstrated relative insensitivity to misalignment, with the efficiency remaining at 84.3% when offset by 50 mm and 81.4% for a transfer distance increase to 100 mm. These findings highlight the potential for this novel design to be utilized in challenging underwater transfer scenarios.

Inductive power transmission technology provides a new way to solve the energy problem of autonomous underwater vehicles (AUVs). The performance of the magnetic coupler determines the system transfer capacity. A novel open‐type magnetic coupler with a simple structure, lightweight, strong anti‐misalignment performance and high self‐inductance stability is proposed for the arc‐shaped shell of AUV. The proposed magnetic coupler employs an arc‐shaped transmitter and the receiver uses an H‐shaped ferrite core to realize the close coupling of magnetic flux in the vertical direction. The parameters of the magnetic coupler are optimized based on ANSYS Maxwell simulation, which ensures its coupling performance and anti‐misalignment performance while minimizing the volume and weight of the receiver. To verify the proposal, a wireless charging system with a 183.9 g receiver is built. The maximum self‐inductance change rate of the coil and maximum coupling coefficient change rate under the conditions of axial misalignment from −25 mm to 25 mm and rotational misalignment from −10° to 10° are 2.9% and 14.3%, respectively. In the case of full alignment, it can deliver 735.6 W at a DC‐DC efficiency of 90.87%.

The wireless power transmission (WPT) of an autonomous underwater vehicle (AUV) tends to have non-negligible eddy current loss with increasing frequency or coil current due to the conductivity of seawater. In this paper, the inductor-capacitor-capacitor and parallel (LCC-P) topology and the magnetic coupler with an H-shaped receiver structure are chosen to achieve a compact system on the receiving side. The conditions for constant current output of the LCC-P topology are analyzed based on the cascaded circuit analysis method. The traditional parameter design method does not consider the influence of eddy current loss on the system circuit model, by introducing the equivalent eddy current loss resistance at both the transmitting side and receiving side, a modified circuit model of the WPT system in the seawater condition was obtained. Afterward, a nonlinear programming model with the optimal efficiency of the constant current mode as the objective function is established, and the genetic algorithm is used to obtain the optimal system parameters. An underwater AUV-WPT prototype was built and the finite element simulation and experimental results verified the theoretical analysis.