Calculation of cogging torque for stator interior permanent magnet machine

The calculation of cogging torque for the SIPM machine is carried out based on the finite element analysis. It is shown that the cogging torque calculated by using virtual work method is close to each other under different meshes and contour models. However the calculation of the Maxwell stress tensor method is more sensitive to the mesh and contour model. So it is extremely important for the Maxwell stress tensor to select appropriate meshes and integration contour. The experimental result shows that the measured one is close to the predicted one.