This article mainly studies the tilting torque characteristic of a novel iron-cored tiered-type permanent magnet spherical motor (T-PMSpM), which has the merit of large torque ability benefitted from the use of iron cores in both rotor and stator. However, the use of ferromagnetic materials also makes the iron-cored T-PMSpM much different from other air-cored spherical motors. Thus, the influence on the tilting torque characteristic is investigated theoretically and numerically. First of all, the active tilting torque is obtained based on a simplified model of air-gap magnetic field distribution. According to this model, the influence of the magnetic field distortion caused by the tilting motion is evaluated. Then, the characteristic of the restoring torque, which obviously exists in the iron-cored T-PMSpM and hinders the tilting motion, is analyzed under different working conditions. The three-dimensional finite-element analysis (FEA) is adopted to calculate the accurate output tilting torque. Finally, an experimental procedure is designed to measure the output tilting torque of the prototype motor for verification. The measured results are compared with the FEA results.

中文翻译：

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铁芯分层式永磁球形电动机的倾斜转矩分析

本文主要研究一种新型铁芯分层式永磁球形电动机（T-PMSpM）的倾斜转矩特性，该特性得益于在转子和定子中均使用铁芯而具有大转矩能力的优点。但是，铁磁材料的使用也使铁芯T-PMSpM与其他空芯球形电动机大不相同。因此，从理论上和数值上研究了对倾斜扭矩特性的影响。首先，基于气隙磁场分布的简化模型获得主动倾斜扭矩。根据该模型，评估了由倾斜运动引起的磁场畸变的影响。然后，恢复转矩的特性很明显地存在于铁芯T-PMSpM中，并阻碍了倾斜运动，在不同的工作条件下进行分析。采用三维有限元分析（FEA）来计算准确的输出倾斜扭矩。最后，设计了一个实验程序来测量原型电机的输出倾斜扭矩，以进行验证。将测量结果与FEA结果进行比较。