Owing to the high speed and frequency required in electric machine industry, the significance of ac resistance has been increasing. This study investigates the ac resistance of windings according to the configuration of strands. The mechanism of generating the ac resistance in winding conductors was investigated with respect to the slot leakage flux and eddy current. Then, when applying the strands to the winding, the concept of unbalanced impedance was introduced to characterize the additional ac resistance due to circulating current. The analytic method to calculate ac resistance describing the above phenomena is derived and verified by FEA results. Afterward, the ac resistances of varying numbers and arrangements of strands were separately studied via finite element analysis. In addition, a method to avoid increasing the ac resistance was suggested based on impedance equalization when applying strands. Finally, experiments were conducted to verify the effect of the strand configuration on ac resistance. An E- and I- shaped core, which can be the rendering of common electric machines, such as motors, generators, and transformers, was manufactured and tested with winding specimens. Consequently, the test results showed a similar trend as the analytical results.

中文翻译：

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根据绞线配置研究槽内绕组导体的交流电阻

由于电机行业对速度和频率的要求很高，交流电阻的重要性日益增加。本研究根据股线的配置研究绕组的交流电阻。根据槽漏磁通和涡流研究了绕组导体中产生交流电阻的机制。然后，当将股线应用于绕组时，引入了不平衡阻抗的概念来表征由于循环电流而产生的额外交流电阻。描述上述现象的计算交流电阻的解析方法是通过有限元分析结果推导出和验证的。随后，通过有限元分析分别研究了不同股数和排列的交流电阻。此外，在应用绞线时，基于阻抗均衡建议了一种避免增加交流电阻的方法。最后，进行了实验以验证绞线配置对交流电阻的影响。制造了一个 E 形和 I 形磁芯，并用绕组试样对其​​进行了测试，该磁芯可以是常见电机（例如电动机、发电机和变压器）的渲染。因此，测试结果显示出与分析结果相似的趋势。