Induction motors' faults detection and localization using stator current advanced signal processing techniques

Abstract

The reliability of power electronics systems is of paramount importance in industrial, commercial, aerospace, and military applications. The knowledge about fault mode behavior of an induction motor drive system is extremely important from the standpoint of improved system design, protection, and faulttolerant control. This paper addresses the application of motor current spectral analysis for the detection and localization of abnormal electrical and mechanical conditions that indicate, or may lead to, a failure of induction motors. Intensive research effort has been for some time focused on the motor current signature analysis. This technique utilizes the results of spectral analysis of the stator current. Reliable interpretation of the spectra is difficult since distortions of the current waveform caused by the abnormalities in the induction motor are usually minute. This paper takes the initial step to investigate the efficiency of current monitoring for diagnostic purposes. The effects of stator current spectrum are described and the related frequencies determined. In the present investigation, the frequency signature of some asymmetrical motor faults are well identified using advanced signal processing techniques, such as high-resolution spectral analysis. This technique leads to a better interpretation of the motor current spectra. In fact, experimental results clearly illustrate that stator current high-resolution spectral analysis is very sensitive to induction motor faults modifying main spectral components, such as voltage unbalance and single-phasing effects.

State of the Art and Trends in the Monitoring, Detection and Diagnosis of Failures in Electric Induction Motors

“…Thus, the greater the difference with respect to the amplitude of the fundamental wave, the greater the damage, Thomson and Fenger [33], Soto and De la Torre [45]; see Figure 8 and Table 12. Benbouzid [46] stated that current analysis does not allow for detection of the distribution of bars in the rotor when these are broken and located in various parts of the engine. However, when the amplitude of the harmonics is 50 dB, smaller than the fundamental wave, it could be considered that the motor is in good condition.…”

“…= Frequency of the network = Number of spheres = Mechanical speed of the rotor (Hz) = Diameter of the spheres = Bearing pitch diameter = Contact angle between the spheres and the tracks = 1, 2, 3, … If the number of spheres is between six and twelve, the characteristic frequencies of failures can be approximated in most bearings by (20) and (21) [46].…”

“…= Components associated with eccentricity Benbouzid [46], proposed a method for determining the components of the velocity and torque spectrum ( + ) and another that defines the lateral bands ( ) of the motor power supply.…”

A Simple Spectral Observer

“…The estimation of a signal in the context of this work means to find the coefficients of a linear combination of functions-sines a cosines functions in our case-that approximates a signal of interest such that it can be reconstructed [6]. Spectral observers are useful in a wide number of applications, e.g., for determining the source of harmonic pollution in power systems [7], for the simulation of the sea surface [8], for fault diagnosis in motors [9,10] or in vibrating structures, such as aerospace and mechanical structures, marine structures, buildings, bridges and offshore platforms.…”

Induction machine fault detection enhancement using a stator current high resolution spectrum

“…In order to overcome the poor resolution of these techniques, high resolution techniques have been proposed which require an a priori knowledge about the signal such as MUSIC and ESPRIT [13]- [16]. In non stationary environment, more so phisticated techniques have been investigated such as time frequency representations [17], [18] and time-scale techniques [19].…”