Multi-Objective Optimization of a Coaxial Magnetic Gear under High Speed Operation Mode

In this article, a multi-objective optimization (MOO) is implemented, aiming at enhancing the torque and efficiency capability under high speed operation mode of the coaxial magnetic gear (CMG). Firstly, the torque and loss characteristics of CMG under different rotate speed is analyzed based on finite element method (FEM). It is found that the magnetic modulation process can cause eddy current loss in permanent magnets, which deteriorates both the torque performance and the efficiency of CMG. Then, a Kriging surrogate model based MOO (Kriging-MOO) is adopted to reduce the FEM computational burden. Moreover, a 2-layer optimization strategy is used to reduce the number of decision variables. To guarantee the mechanical interface of the CMG unchanged, the outer size and inner size of CMG are kept constant. Comparing with the initial design, the optimized CMG shows a 3.4% and 6.8% growth in torque and efficiency.