Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores

Abstract

When the cogging torque is reduced greatly, the average output torque of the machine is usually decreased. [...]during the process of reducing the cogging torque, its effect to the average output torque should be considered. [...]the structure of CPMs is much more complex than that of the conventional radial-flux PMSM. [...]it is difficult to accurately calculate the cogging torque of CPMs with SMC cores by using the analytical method. [...]in the PMSM with a SMC core, the co-energy in the stator core cannot be ignored, as the permeability of the SMC material is not high enough for the magneto motive force drop in the core to be neglected. [...]the accurate calculation of the cogging torque in the CPM with a SMC core should be carried out by the FEM. The main reason is that the permeability of the SMC is much lower than that of silicon steel. [...]the slotting of the stator pole has little impact on the equivalent air gap. 5.