Purpose

This paper presents the design techniques applied to a novel fractional-slot 6/4 pole permanent magnet brushless direct current (PMBLDC) motor, for cogging torque reduction. The notable feature of this motor is the simplicity of the design and low production cost. The purpose of this paper is to reduce the peak cogging torque of the motor. The focus is put on the stator topology tuning, and a new design for the stator poles is proposed. By determining the optimum stator pole arc length and the best pole shoe thickness, the cogging torque is significantly reduced. This new optimised motor design has been analysed in detail. The validation of the results is documented with respective figures and charts.

Design/methodology/approach

At the beginning, the design data for the 6/4 pole PMBLDC motor with concentrated three phase windings and asymmetric stator pole arcs is presented. In the study, this motor is taken as a reference model (A₀, T₀). A full performance finite element analysis of the reference motor has been carried out, and the weak points in the motor design have been identified. By simple design techniques, tuning the stator pole geometry, a two-stage design optimisation for cogging torque minimisation has been performed and the solution array has been derived. The optimised model is selected and proposed (A_opt, T_opt). The comparative analysis of the reference and optimised motors show the advantages of the proposed novel design and prove the methodology.

Findings

The results of the work demonstrate how simple design techniques can minimise the peak of the cogging torque profile, while maintaining the specified electromagnetic torque value. The sensitivity of the cogging torque profile because of changes of the stator pole design inside the prescribed constraints is apparent. The stator poles of the reference motor have an arc length of 85° and pole shoe thickness of 6 mm. The newly shaped stator poles have an arc length of 78.5° and pole shoe thickness 4.8 mm. The peak-cogging torque has been reduced from 0.158 Nm to a respectable value of 0.066 Nm. However, to reduce electromagnetic torque ripple and pulsations, further investigations are required.

Originality/value

The paper presents an approach to cogging torque reduction for a 6/4 PMBLDC motor. A two-step original design procedure is introduced and an optimised stator pole geometry is defined. The minimised cogging torque has been demonstrated with improved usage of the active materials. This work could serve as a good basis for further optimisation of the motor design.

中文翻译：

---

分数槽PMBLDC电机齿槽转矩减小的设计技术

目的

本文介绍了设计技术应用于新颖的分数槽6/4极永磁无刷直流（PMBLDC）电机，以减小齿槽转矩。该电机的显着特点是设计简单，生产成本低。本文的目的是减少电动机的峰值齿槽转矩。重点放在定子拓扑调整上，并提出了一种新的定子磁极设计。通过确定最佳定子极弧长和最佳极靴厚度，可以大大降低齿槽转矩。已对这种新的优化的电动机设计进行了详细分析。结果验证通过相应的图形和图表记录。

设计/方法/方法

首先，介绍了具有集中三相绕组和不对称定子极弧的6/4极PMBLDC电机的设计数据。在研究中，该电动机被作为参考模型（A ₀，T ₀）。已对参考电动机进行了全性能的有限元分析，并确定了电动机设计中的薄弱环节。通过简单的设计技术，调整定子磁极的几何形状，进行了两阶段的优化设计，以最小化齿槽转矩，并得出了解决方案阵列。选择和提出优化模型（A _opt，T _opt）。对参考电动机和优化电动机的比较分析显示了所提出的新颖设计的优点并证明了该方法。

发现

工作结果表明，简单的设计技术如何在保持指定的电磁转矩值的同时最大程度地减小齿槽转矩曲线的峰值。由于在规定的约束范围内定子极设计的变化，齿槽转矩曲线的灵敏度是显而易见的。参考电动机的定子磁极的弧长为85°，磁极靴的厚度为6 mm。新成型的定子磁极的弧长为78.5°，磁极靴厚度为4.8 mm。峰值齿槽转矩已从0.158 Nm降低到0.066 Nm的可观值。但是，为了减少电磁转矩的波动和脉动，需要进一步的研究。

创意/价值

本文提出了一种降低6/4 PMBLDC电动机齿槽转矩的方法。介绍了两步原始设计程序，并定义了优化的定子磁极几何形状。已经证明，随着活性材料用量的增加，齿槽转矩最小。这项工作可以作为进一步优化电机设计的良好基础。