Limitation in manufacturing tolerances and assembly imperfections are the source of asymmetrical stator axes (ASA) defect, in particular, in a vacuum dry pumps (VDP) where the canned permanent magnet machines (CPMMs) are with fractional slot concentrated winding (FSCW). The performance and multi-physical field of CPMM in the vacuum environment is vulnerable to ASA. This work provides comprehensive research on the influence of ASA on the performance and multi-physical field of CPMM for VDP. This article establishes a mathematical model and Park transformation of a 1.6kW 6-pole/9-slot CPMM under the ASA condition. With the universality of ASA and not so strictly symmetrical stator axes as commonly expected, the experimental results demonstrated the significant impacts of ASA on the drive performance and multi-physical field, especially the inductance characteristics, the symmetry degree of stator current and flux linkage, rotor electromagnetic force and stator electromagnetic vibration of CPMM. The obtained conclusions can act as a significant reference for robust design and analysis of electric machines and drives.

中文翻译：

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非对称定子轴对带矢量转换器供电的真空干泵用屏蔽永磁电机性能和多物理场的影响

制造公差和装配缺陷的限制是不对称定子轴 (ASA) 缺陷的根源，特别是在真空干泵 (VDP) 中，其中封闭式永磁电机 (CPMM) 具有分数槽集中绕组 (FSCW)。CPMM 在真空环境中的性能和多物理场容易受到 ASA 的影响。这项工作提供了对 ASA 对 VDP CPMM 性能和多物理场影响的综合研究。本文建立了1.6kW 6极/9槽CPMM在ASA条件下的数学模型和Park变换。由于ASA的普遍性，而不是像通常预期的那样严格对称的定子轴，实验结果证明了ASA对驱动性能和多物理场的显着影响，特别是CPMM的电感特性、定子电流和磁链的对称度、转子电磁力和定子电磁振动。所得结论可为电机和驱动器的稳健设计和分析提供重要参考。