This article investigates the impact of scaling on the electromagnetic performance of surface-mounted permanent-magnet Vernier (SPM-V) machines with a main focus on open-circuit induced Electro Motive Force (EMF). Three different power ratings, i.e., 3 kW, 500 kW, and 3 MW, have been chosen for this article. For each power rating, the SPM-V machines are analyzed for different slot/pole number combinations to compare their optimal performance with a conventional SPM machine. Step-by-step development of an analytical equation is presented for the prediction of induced EMF taking into account the interpole leakage of rotor permanent-magnets. 2-D finite-element analysis (FEA) has been used to validate the analytical equation across different power ratings. The analytical equation is thereafter utilized to study the influence of different geometric parameters on the performance of the SPM-V machines. It reveals that the back EMF and torque of SPM-V machines, for a given normalized pole pitch (rotor pole pitch to magnetic airgap length), are unaffected by the increase in airgap length due to scaling. However, the power factor of SPM-V, unlike the conventional SPM, reduces significantly with the increase in electrical loading due to the scaling effect. The analytical model for induced EMF and the 2-D FEA predicted results are validated by experiments using conventional SPM and SPM-V machine prototypes.

中文翻译：

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结垢对表面贴装永磁游标机电磁性能的影响

本文研究了缩放对表面贴装永磁游标 (SPM-V) 电机电磁性能的影响，主要关注开路感应电动势 (EMF)。本文选择了三种不同的额定功率，即 3 kW、500 kW 和 3 MW。对于每个额定功率，SPM-V 机器都会针对不同的槽/极数组合进行分析，以将它们的最佳性能与传统 SPM 机器进行比较。考虑到转子永磁体的极间泄漏，分析方程的逐步开发用于预测感应电动势。二维有限元分析 (FEA) 已用于验证不同额定功率下的分析方程。然后利用解析方程来研究不同几何参数对 SPM-V 机器性能的影响。它表明，对于给定的归一化极距（转子极距与磁气隙长度），SPM-V 电机的反电动势和扭矩不受因缩放导致的气隙长度增加的影响。然而，与传统的 SPM 不同，SPM-V 的功率因数会因缩放效应而随着电气负载的增加而显着降低。感应电动势的分析模型和二维 FEA 预测结果通过使用传统 SPM 和 SPM-V 机器原型的实验进行验证。不受因缩放导致的气隙长度增加的影响。然而，与传统的 SPM 不同，SPM-V 的功率因数会因缩放效应而随着电气负载的增加而显着降低。感应电动势的分析模型和二维 FEA 预测结果通过使用传统 SPM 和 SPM-V 机器原型的实验进行验证。不受因缩放导致的气隙长度增加的影响。然而，与传统的 SPM 不同，SPM-V 的功率因数会因缩放效应而随着电气负载的增加而显着降低。感应电动势的分析模型和二维 FEA 预测结果通过使用传统 SPM 和 SPM-V 机器原型的实验进行验证。