Analysis on cogging torque in axial field flux-switching permanent magnet machine

The cogging torque in a novel 12/10 poles axial field flux-switching permanent magnet(AFFSPM) machine was studied by combining analysis method and finite element method(FEM).The analytical expression of cogging torque in the AFFSPM machine was built,the cogging torques for the different structure parameters were calculated on the basis of 3D whole field finite element method,and the change regularity between the cogging torque and the structure parameters was obtained.Namely,when the stator slot width,stator tooth width and the permanent magnet magnetization width are equal,and the rotor tooth is 1.4 times as wide as the stator tooth,the cogging torque in the AFFSPM machine is the least.In addition,the cogging torque is directly proportionate to the thickness of the stator,and less affected by the thickness of the rotor.At last,the effective methods for reducing the cogging torque in the AFFSPM machine were suggested after considering a balance between the cogging torque and the induced electromotive force(EMF).