Excessive vibrations in motor operation can be a cause of premature failure in many industrial applications; therefore, effective solutions to accurately measure vibrations are required. A common approach to measure vibrations is through the motor current signature analysis, as torque oscillations produce characteristic frequency components in the current spectrum; this approach is suitable for those industrial applications where the rotating parts are not directly accessible for sensor installation, e.g., electrical submersible pumps which are usually deep underground or underwater. The detection of vibrations from the current spectrum is particularly challenging in high-power motors, where the ratio between the amplitude of the sideband spectral components caused by vibrations and the amplitude of the fundamental component is so small that the former is likely to be masked by the spectral leakage of the latter when a traditional Fourier analysis is employed. This article proposes a method to improve the sideband amplitude measurement by compensating for the leakage error in the current spectrum. The method is applied, in particular, to the detection of vibrations caused by a shaft angular misalignment, but it can be applied to other types of vibrations as well. The method is first illustrated through simulation results and then experimentally validated on a smaller-scale motor. Results confirm the ability of the proposed method to accurately measure the sideband amplitude even when it was originally completely hidden by the spectral leakage of the fundamental component.

中文翻译：

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用于潜水泵轴未对准检测的电机电流特征分析中的泄漏误差补偿

电机运行中的过度振动可能是许多工业应用中过早失效的原因；因此，需要有效的解决方案来准确测量振动。测量振动的常用方法是通过电机电流特征分析，因为扭矩振荡会在电流谱中产生特征频率分量；这种方法适用于那些无法直接接触到传感器安装的旋转部件的工业应用，例如通常位于地下深处或水下的电动潜水泵。从电流频谱中检测振动在大功率电机中尤其具有挑战性，其中由振动引起的边带频谱分量的幅度与基波分量的幅度之间的比率非常小，以至于当采用传统的傅立叶分析时，前者很可能被后者的频谱泄漏所掩盖。本文提出了一种通过补偿电流频谱中的泄漏误差来改进边带幅度测量的方法。该方法尤其适用于检测由轴角错位引起的振动，但也可以应用于其他类型的振动。该方法首先通过仿真结果进行说明，然后在较小规模的电机上进行实验验证。