Accurately measuring the cogging torque, hysteresis torque, and iron losses of permanent magnet (PM) motors is a challenging task. This is especially true for sub-fractional horsepower (SFHP) variants used, e.g., in auxiliary drives for automotive fan and pump applications. Their cogging torque and hysteresis torque peak values are often in the sub-milli-Newton meter range, causing conventional measuring methods and devices to fail as especially friction impedes the measurement significantly. Moreover, their iron losses are hard to determine and usually merely estimated in the literature. This article presents an unconventional rheometer-based method to determine both 1) the cogging torque and hysteresis torque of SFHP PM motors and 2) their iron losses by evaluating the observed offset torque. Two SFHP outer-rotor PM motor topologies for fan applications are analyzed, i.e., a claw-pole motor and a salient-pole motor. The results show that, with the proposed setup, settings, and evaluation, a rheometer can successfully be used to determine the cogging torque and hysteresis torque waveforms in the sub-milli-Newton meter range and the iron losses of SFHP motors, both with excellent accuracy.

中文翻译：

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基于流变仪的亚分马力电机齿槽和磁滞转矩和铁损测定

准确测量永磁 (PM) 电机的齿槽转矩、磁滞转矩和铁损是一项具有挑战性的任务。这对于使用的次分马力 (SFHP) 变体尤其如此，例如用于汽车风扇和泵应用的辅助驱动器。它们的齿槽转矩和滞后转矩峰值通常在亚毫牛顿米范围内，导致传统的测量方法和设备失效，因为摩擦尤其严重阻碍了测量。此外，它们的铁损难以确定，通常仅在文献中进行估算。本文介绍了一种基于流变仪的非常规方法，可通过评估观察到的偏移扭矩来确定 1) SFHP PM 电机的齿槽转矩和磁滞转矩，以及 2) 它们的铁损。分析了用于风扇应用的两种SFHP 外转子永磁电机拓扑结构，即爪极电机和凸极电机。结果表明，通过建议的设置、设置和评估，流变仪可成功用于确定亚毫牛顿米范围内的齿槽转矩和滞后转矩波形以及 SFHP 电机的铁损，两者均具有出色的性能。准确性。