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

A structural optimization design method of DD orthogonal coil in the seawater environment is introduced in this paper, which is suitable for underwater AUV equipment. The electromagnetic field model considering the effect of the high conductivity of seawater medium is established. The Eddy current equivalent resistance is introduced to characterize the eddy current loss caused by seawater medium. The relationship between eddy current equivalent resistance and DD orthogonal coil structure size is analyzed, and the influence of structure parameters on power transfer efficiency in seawater medium is further pointed out. The analysis results show that the DD orthogonal coil in seawater medium has an extreme point of optimal design when the power transfer efficiency and power transfer density are the optimization objectives. NSGA-II algorithm is used to optimize the structure parameters of the DD orthogonal coil. The coil efficiency is obtained by finite element simulation. Pareto frontier curve under effective constraints. Finally, a 3.3- kW experimental prototype was built to verify the feasibility. The DD orthogonal coil power transfer density is 33.78 kW/m2. The experimental results indicate that the power transfer efficiency of 91.92% is achieved with the power of 2.3kW and transmission distance is 100mm