Compared with internal-rotor switched reluctance motors (SRMs), external-rotor (ER) SRMs can show different vibration and acoustic noise behavior due to the differences in the designs, e.g. thinner rotor back iron to achieve smaller inertia, and longer stator pole height to improve the electromagnetic performance. This paper presents the considerations in the modeling and analysis of the acoustic noise sources of an ER SRM stator and rotor. The harmonic components of the stator tangential force density and rotor radial force density are analyzed and compared. The vibration modes, the vibration behavior, and acoustic noise of the stator and rotor are also compared. A 12/16 external-rotor SRM designed for a direct-drive E-bike application is used for the modeling, analysis, and experimental validation of vibration and acoustic noise. It is concluded that both the stator tangential vibration and the rotor radial vibration can be sources of the acoustic noise in an ER SRM.

中文翻译：

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12/16外转子开关磁阻电动机的声源：定子切向振动和转子径向振动

与内部转子磁阻电机（SRM）相比，由于设计上的差异，外部转子（ER）SRM可以表现出不同的振动和声噪声行为，例如，更薄的转子背铁可实现较小的惯性，以及更长的定子磁极高度改善电磁性能。本文提出了对ER SRM定子和转子的声噪声源进行建模和分析时应考虑的因素。分析并比较了定子切向​​力密度和转子径向力密度的谐波分量。还比较了定子和转子的振动模式，振动行为以及噪声。专为直接驱动电动自行车应用设计的12/16外转子SRM用于振动和声噪声的建模，分析和实验验证。