Optimal design of the rotor structure for interior permanent magnet synchronous motor

The permanent magnet synchronous motors are widely used in various industrial applications due to many advantages such as high power density, high efficiency, low manufacturing cost and so on, but cogging torque and moment of inertia are the most important factors affecting the performance and control precision. In this paper, firstly, the cogging torque can be effectively reduced by taking the auxiliary notches, which was obtained through the analysis of the mathematical model of cogging torque and no-load magnetic field of yoke. After that, the rotor iron core was holed to reduce the moment of inertia, which had no effect on the performance. Finally, an interior permanent magnet synchronous motor whose power is 7.5kW was taken as example. Optimization was done to the rotor structure by using the method mentioned above, which was feasibility verifying by analysis of finite element using Ansoft.