Parametric analysis of the magnet location based on straight-shape internal permanent magnet synchronous motor

For straight-shape magnet internal structure, air gap flux density and cogging torque are considerably affected by installation position of magnets under the premise of the same amount of the permanent magnet involved. An analytical mathematical model is established based on energy method and magnetic path analysis method, for illustrating mathematical correlation of cogging torque and the magnets position. Cogging torque parameter has been swept with respect to installation position of magnets utilizing motor model. Based on the modular structure, the modules with different materials are set up to avoid local saturation around the root region of stator tooth and weaken the cogging torque. The validation of mathematical expression and the effectiveness of modular structure are proved by finite element analysis.