关键词: 无刷直流电动机, 钐铁氮, Halbach, Maxwell

Abstract: A new permanent magnet rotor , applicated the new rare earth permanent magnet material SmFeN , was designed for a 6 - slot 8 - pole internal rotor brushless DC motor. The original permanent magnet rotor was composed of Halbach magnetized bonded NdFeB magetic ring and magnetic back yoke. The SmFeN equivalent scheme and optimization scheme without magnetic back yoke were designed based on the ANSYS Maxwell 2D software platform. The theoretical model formula of Halbach magnetized inner rotor magnetic ring was introduced to estimate the size of the optimization scheme. The engineering significance of the theoretical model formula was verified by the comparsion of simulation data and the theoretical values. Prototyping testings were carried out for the SmFeN equivalent scheme and optimization scheme. Especially for the equivalent scheme, the surface magnetic curve of the middle region with magnetic back yoke, which compared with the one of the end region, became flat in the peak and valley. So the magnetic back yoke could influence the magnetization direction of magnetic powder when mangetic ring occurs magnetic saturation. The no-load and load performace of the prototype for optimization scheme were simlar to the original motor, and the assembly process was simplified by removing the magnetic back yoke. the overall weight of the rotor was reduced by 28%.

Key words: brushless DC motor, SmFeN, Halbach, Maxwell