Cogging torque minimization in double sided axial flux magnetic gear

Magnetic gears (MGs) have received little attention due to their low torque density and low torque quality. A way to increasing torque density in MGs is using axial flux configuration which increases permanent magnet surface while reducing the required iron core. An axial flux MGs can be designed as a single or dual sided one. The solution to the high axial forces in-between the disks, preferably is a dual sided design. This paper focuses on the double sided axial flux MG structure, by studying the effects of skewing PMs and modulators as an effective passive method to suppress the cogging torque caused by interaction between high speed PMs and ferromagnetic pole pieces. The simulations and comparisons of different skewing methods using percentage of cogging torque to average torque are implemented by 3-D Finite Element Method.