钐铁氮永磁转子在无刷直流电动机的应用与研究

Application and Research of SmFEN Permanent Magnet Rotor on Brushless DC Motor

针对一款6槽8极内转子无刷直流电动机,开展新型稀土永磁钐铁氮(SmFeN)永磁转子的设计应用。原永磁转子由Halbach磁化的粘接钕铁硼磁环和导磁背轭组成。基于Maxwell 2D平台,求解得到钐铁氮材料的等效方案和取消导磁背轭的优化方案。引入Halbach磁化的内转子磁环理论模型公式来估算优化方案尺寸,通过仿真数据及理论值的比较验证了该理论模型公式的工程意义。对等效方案和优化方案样机进行实验。特别针对等效方案,在中部含导磁背轭区域的表磁曲线与端部表磁曲线相比在峰谷处变成平顶。表明在磁化饱和时导磁背轭会影响各向异性的钐铁氮磁粉取向。优化方案样机的空载和负载性能与原机相近,取消了导磁背轭简化装配,且转子质量整体下降28%。

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%.