Optimization of the pole piece in coaxial magnetic gears for transfer torque ripple improvement

In this paper, the Box-Behnken design (BBD), which is a response surface method (RSM), was used to deduce a pole piece form that is able to effectively reduce the transfer torque ripple of a coaxial magnetic gear. A 2-D numerical analysis based non-linear finite element method (FEM) was used for the analysis between the response variables and the designed variables selected by the BBD. In addition, the reaction variable estimation equation based on the design variables was determined through a multiple regression analysis and analysis of variance (ANOVA). The characteristics of the initial model and optimum model deduced through a response surface analysis were compared to prove the validity of the optimized design.