径向充磁表贴式正弦磁极电机转矩密度最大化研究

本文提出一种利用三次谐波削极，增加径向充磁表贴式正弦磁极永磁同步电机输出转矩而不增加转矩脉动的方法。根据永磁磁极形状可以将表贴式永磁电机分为弧形永磁磁极和面包形永磁磁极。对于所有极槽配合的径向充磁弧形永磁磁极永磁电机，注入最优三次谐波幅值为基波的1/6；但对于径向充磁面包形永磁磁极永磁电机，最优三次谐波幅值随极对数（P）、永磁体厚度和转子半径而变化，因此现有推导的最优三次谐波解析模型是不准确的，对于面包形永磁磁极永磁电机，此模型是无效的。本文推导了径向充磁面包形表贴式正弦磁极注入最优三次谐波幅值解析模型，可以在不提高转矩脉动的情况下最大程度的提高转矩。最后用有限元验证了模型的准确性。

Research on Torque Density Maximization of Surface Mounted Sinusoidal Pole Motor with Radial Magnetization

This paper presents a method to increase output torque without deteriorating the torque ripple in radial magnetized surface-mounted permanent magnet (SPM) machines having sinusoidal shaped pole by using third harmonic (Sine+3rd) shaping method. In accordance with the profile of SPM, it can be classified into arc magnet and “bread-loaf” magnet. For all slot/pole combinations of SPM machine with radial magnetized arc magnet, it is already found that the optimal third harmonic which is injected into sinusoidal PM shape is fixed and equal to 1/6 of the fundamental one1]. However, such optimal value is varied with pole pair numbers (p), magnet thickness and rotor radius for machine having radial magnetized “bread-loaf” magnet. Therefore, the developed Sine+3rd shaping method is not accurate enough and invalid for SPM machine having “bread-loaf” magnet pole. In this paper, an analytical model to obtain the optimal third harmonic injected into radial magnetized SPM machine with sinusoidal shaped “bread-loaf” magnet is derived to achieve maximum torque improvement without deteriorating torque ripple.