Novel Stator Slot Opening to Reduce Electrical Machine Bearing Currents
Novel Stator Slot Opening to Reduce Electrical Machine Bearing Currents
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DOI：
10.1109/tmag.2023.3283794
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发表时间：
2023-05
影响因子：
2.1
通讯作者：
D. De Gaetano;Wenjun Zhu;Xiangyu Sun;Xiao Chen;A. Griffo;G. Jewell
中科院分区：
文献类型：
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作者：
D. De Gaetano;Wenjun Zhu;Xiangyu Sun;Xiao Chen;A. Griffo;G. Jewell
滚珠轴承主要用于电机中，高频共模电流会影响其寿命。本文提出了一种新的锯齿形定子槽口(SO)几何结构，以减少绕组到转子的电容，从而降低轴承电压比(BVR)和电火花加工轴承电流。实现了一个改进的分析模型，允许计算不寻常的SO几何图形的$C_{\Text{WR}}$。对Z字形、斜形和原始(经典SO构型)电机进行了静电和电磁有限元分析(FEA)比较。这些比较表明，Z字形模型在降低BVR方面表现出最好的性能，同时保持了接近原始机器的扭矩性能。将该模型与简化后的经典模型进行了比较，结果表明经典模型的扭矩性能劣化程度更高。研究表明，之字形模型可以很好地减小电机轴承电流。对两种典型构型和之字形构型的发动机样机进行了验证试验。此外，改进的解析方法可以帮助工程技术人员和研究人员对特殊的SO几何形状进行高精度的$C{\Text{WR}}$计算。
Ball bearings are largely used in electrical machines, where high-frequency common-mode currents affect their lifetime. This document presents a novel zig-zag stator slot opening (SO) geometry to reduce the winding-to-rotor capacitance $C_{\text {wr}}$ with the consequent reduction of bearing voltage ratio (BVR) and electrical discharge machining bearing currents. An improved analytical model to permit the calculation of $C_{\text {wr}}$ for unusual SO geometries is implemented. Electrostatic and electromagnetic finite-element analysis (FEA) comparisons between the zig-zag, oblique, and original (classical SO configuration) machines are performed. These comparisons suggest that the zig-zag model presents the best performance in terms of BVR reduction while keeping torque performance close to the original machine. An additional comparison between the novel zig-zag model and the classical one with reduced SO to have the same $C_{\text {wr}}$ values is proposed, showing a higher degradation in terms of torque performance for the latter. The study shows that the zig-zag model could be a good candidate to reduce effectively electrical machine bearing currents. A validation test is proposed on two motorette prototypes having classical and zig-zag SO configurations, respectively. Moreover, the improved analytical method can be helpful for engineers and researchers to calculate $C_{\text {wr}}$ with good accuracy for unusual SO geometries.