Optimum Design for Slot-type of Stator Based on PM Motor with Halbach Structure

The performance of permanent magnet motor is directly influenced by the PM structure of rotor and the slot type of stator. An emerging rotor magnetization type of PM motor is Halbach structure, which has obvious advantages in comparison to ordinary permanent structures and in application, especially in the design of propeller integration system. Commonly, Halbach array is used in discrete permanent magnet structure on the rotor of machine. On the stator, air gap flux density varies as the slot type changes, and complex slot types will bring about complex air gap equivalent process of the motor, which will influence the procedures of simulation calculation and experiments. According to the characteristics of Halbach array, the intensifying effect of the Halbach array on magnetic flux density of air gap is analyzed in this paper, and the electromagnetic field of PM motor is calculated. By using FEM method, the magnetic flux density of air gap, back phase electromotive force and electromagnetic torque are compared under different slot types. Simulation result shows the peer slot is best. Experiments on a 60kW PM Motor with Halbach Structure and peer slot is in good agreement with simulation.