摘  要：提出了一种信号处理方法——幅值恢复算法作为对定子电流信号进行快速傅里叶变换前的预处理，目的是为了分析除基波以外的谐波从而诊断电机的轻微故障。作为过滤器功能的幅值恢复算法能够把定子电流信号中各次谐波同基波分离开来，过滤结果用于快速傅里叶变换做进一步的频谱分析。幅值恢复算法有其自身优势，包括阻频带足够窄而且仅阻止基频、不使用积分只用简单的代数和三角运算、易从公式直接推导得来，可单独对运行中的电机作初步故障诊断，实验结果验证了系统设计和方法的有效性。
关键词：信号处理；幅值恢复法；定子电流；故障诊断

Abstract: The paper presented a signal processing method-amplitude recovery method that can be used as the signal pre-processing for Fast Fourier Transform (FFT) in order to analyze the spectrum of the other-order harmonics rather than the fundamental frequency in stator currents and to diagnose subtle faults in motors. The amplitude recovery function as a filter can filter out the component of the fundamental frequency from three phases of stator currents of the motor, and the result can be provided to FFT for further spectrum analysis. It has benefits including its impedance-band narrow enough just to filter out the fundamental frequency; its simple operations with algebra and trigonometry without any integration, and its deduction directly from mathematics equations, which can be independently used as preliminary diagnosis of faults in motors. The experiment proves the effectiveness of the proposed system design and method.
Key words: signal processing; amplitude recovery method; stator current; fault diagnosis