Motor current signal analysis is an effective technique for fault diagnosis in the motor drive system. However, in the closed-loop control (CLC) system, the amplitude of periodic faulty harmonic is suppressed by the impact of CLC characteristics, so the severity assessment of faults may fail. In this article, a model reference method based on the theoretical analysis of CLC characteristics is proposed to deal with this problem. First, the faulty harmonic in the q -axis current is extracted from the field-oriented control process as a fault indicator. Then, the bandpass effect is revealed to describe the variation of amplitudes of harmonics in the current spectrum. The variation is caused by the control parameter and architecture in the CLC system. Finally, to improve diagnostic performance, a model reference method is proposed to compensate for the aforementioned variation. The model is established by experimentally measuring the amplitude–frequency response of the closed-loop speed control system. The bandpass effect of the CLC system is validated by simulations in the MATLAB/Simulink environment. Furthermore, experimental validations are conducted on a ball screw platform. The results show that the proposed method is effective to compensate the bandpass effect and helps to achieve better diagnostic performance.

中文翻译：

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带通效应及其在闭环控制系统中的诊断方法

电动机电流信号分析是诊断电动机驱动系统中故障的有效技术。但是，在闭环控制（CLC）系统中，CLC特性的影响会抑制周期性故障谐波的幅度，因此故障严重性评估可能会失败。本文提出了一种基于CLC特性理论分析的模型参考方法来解决这一问题。首先，故障谐波在q 从磁场定向控制过程中提取轴电流作为故障指示器。然后，揭示了带通效应，以描述电流频谱中谐波幅度的变化。变化是由CLC系统中的控制参数和体系结构引起的。最后，为了提高诊断性能，提出了一种模型参考方法来补偿上述变化。该模型是通过实验测量闭环速度控制系统的幅度-频率响应而建立的。通过在MATLAB / Simulink环境中进行仿真，可以验证CLC系统的带通效应。此外，在滚珠丝杠平台上进行了实验验证。