Multi-objective Optimization of Double-D Orthogonal Coil in the Underwater Environment

This article presents a novel design and optimization method for a double-D (DD) orthogonal coil in the wireless power transfer (WPT) system for underwater environments, with the aim of maximizing power transfer efficiency and power transfer density. First, a magnetic circuit model of the DD orthogonal coil is developed to analyze the influence of each coil parameter on its performance. Finite element simulations are then performed to validate the proposed model and further analyze the parameters. Based on this analysis, design guidelines for multi-objective optimization are presented. The Non-dominated Sorting Genetic Algorithm (NSGA-II) is used to optimize the coil parameters for power transfer efficiency and power transfer density. The Pareto front of the coil coupling coefficient and quality factor is obtained for efficiency and transfer density in underwater environments. Finally, a 3-kW DD orthogonal coil experimental system is built and tested, and the experimental results demonstrate that the proposed DD orthogonal coil achieves a higher transmission efficiency and energy transfer density of 91.73% and 33.78kW/m2, respectively. Notably, even at a misalignment of 100 mm, a transfer efficiency of 89.78% is achieved.