动磁式永磁无刷直流直线电机的齿槽力最小化

Minimization of Cogging Force in Moving Magnet Type PMBLDCLM

为提高永磁无刷直流直线电机的性能,必须研究减小其齿槽定位力(齿槽力)的技术措施。根据电磁弹射系统需要推进大质量载荷的要求,提出了1种大推力的动磁式永磁无刷直流直线电机模型。用有限元方法计算了磁极端部与定子齿槽相互作用形成的3种齿槽力分量,由傅里叶变换得到了各分量的功率谱。在对各分量进行频谱分析的基础上得出了产生齿槽力的主要原因是电机推力的二次谐波这一结论,提出了优化磁极宽度以减小齿槽力的方法。对优化设计后的电机模型进行了有限元计算和频谱分析,分析显示该电机模型推力的二次谐波已被大大削弱。计算了不同磁极宽度情况下的电机推力,结果表明采用该方法可以有效减小电机的推力波动。

Researches on reducing cogging force is indispensable for improving the performance of permanent magnet brushless DC lincar motor（PMBLDCLM）. A moving magnet type PMBLDCLM was presented to meet the need of pushing heavy load. Three components of cogging force caused by the reaction of stator slots and magnet edges were calculated by finite element method（FEM） and their power spectrums were computed by Fourier transform. Analysis of the power spectrums leads to a conclusion that the cogging force is caused mainly by the second harmonic of the motor thrust. A method of optimizing magnet width to minimize the cogging force was proposed on the basis of harmonic analysis. The optimal magnet width of presented model was given and the harmonic analysis of the motor cogging force indicated that the second harmonic of the motor thrust was diminished significantly. Finally, several motor models with different magnet width were designed and their thrusts were computed. The FEM calculation results prove that the thrust fluctuation of the motor can be effectively cut down with proposed method.