Brushless dc motor (BLDCM) is a conventional machine type used in the electric bike (e-bike) industry due to its simple controllability and drive system. However, the fluctuating price and scarcity of NdFeB magnets used in BLDCMs, lower power density compared to ac machines, and high torque ripple have pushed researchers in industry and academia to investigate technology alternatives to BLDCMs in e-bike applications. Permanent magnet-assisted synchronous reluctance motor (PMaSynRM) is an attractive option to this end because of its adjustable reluctance torque component and the recent advancements in finite-element (FE)-based design algorithms and implementation. Not yet covered in the existing literature and industry reports for e-bike applications, an in-hub outer rotor PMaSynRM is designed in this article to improve the power density and reduce the torque ripple characteristics for replacing a 500-W commercial BLDCM. The designed PMaSynRM is fabricated and tested to validate the power density and torque ripple improvements compared to an existing Golden Motor MP2 BLDCM counterpart.

中文翻译：

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用于电动自行车推进的外转子 PM 辅助 SynRM 的设计和实验性能评估

由于其简单的可控性和驱动系统，无刷直流电机 (BLDCM) 是电动自行车 (e-bike) 行业中使用的传统机器类型。然而，BLDCM 中使用的 NdFeB 磁铁的价格波动和稀缺性、与交流电机相比较低的功率密度以及高扭矩纹波促使工业界和学术界的研究人员研究电动自行车应用中 BLDCM 的技术替代品。永磁辅助同步磁阻电机 (PMaSynRM) 是一个有吸引力的选择，因为它具有可调节的磁阻转矩分量以及基于有限元 (FE) 的设计算法和实施的最新进展。现有文献和行业报告中尚未涵盖电动自行车应用，本文设计了轮毂内外转子 PMaSynRM，以提高功率密度并降低转矩脉动特性，以替代 500-W 商用 BLDCM。设计的 PMaSynRM 经过制造和测试，以验证与现有的 Golden Motor MP2 BLDCM 对应产品相比，功率密度和扭矩纹波的改进。