Parameter Sensitivity Analysis and Optimization of Electromagnetic Force Waves of Fractional Slot Surface-Mounted PM Motor With External Rotor

Abstract

For PM motor with external rotor, the electromagnetic force wave acting on the surface of the permanent magnet by the air gap magnetic field is the main cause of its electromagnetic vibration. In this paper, an optimization method based on parameter sensitivity for electromagnetic force wave of fractional slot surface-mounted PM motor with external rotor is proposed. Firstly, taking a fractional slot surfacemounted PM motor with external rotor as the research object, Latin Hypercube Design (LHD) is carried out with six structural parameters as design variables, including pole arc coefficient, notch width, air gap length, permanent magnet thickness, tooth width and slot depth, and the parameter sensitivity of different design variables to the average torque and the main radial electromagnetic force wave amplitude is analyzed. Secondly, based on the experimental results of Latin Hypercube Design, a mathematical approximation model is established by using radial basis function neural network method. Then, with the aim of improving the average torque and reducing the amplitude of the main radial electromagnetic force wave, neighborhood cultivation genetic algorithm is applied to optimize the structure of the motor. Finally, the optimized motor scheme is simulated by finite element simulation to verify the feasibility and accuracy of the proposed method.