Online detection method of broken rotor bar fault of cage-type asynchronous motor based on ESPRIT-SAA

Abstract

An online detection method of a broken rotor bar fault of a cage-type asynchronous motor based on ESPRIT-SAA is disclosed. The method is characterized in that: firstly, a rotational invariance technique is applied for stator-current instantaneous signals which are collected according to a certain frequency so that accurate frequency values, rough amplitudes and initial phase angles of a fundamental component and a side frequency component can be acquired; then, a simulated annealing algorithm is used to estimate the accurate amplitudes and initial phase angles of the fundamental component andthe side frequency component of the stator-current instantaneous signals; furthermore, a ratio of the current side frequency component to the current fundamental component can be acquired and the ratio is regarded as a fault characteristic; and then the ratio against a detection threshold can be acquired and a fault index can be determined; finally whether there is the broken rotor bar fault is determined according to the fault index. By using the invention, the broken rotor bar fault of the asynchronous motor can be detected with high sensitivity and high reliability by using very few of stator current signal sampling points. Negative factor influences, such as load fluctuations, noises and the like, can be effectively overcome. The method is very suitable for a low slip ratio operation situation of the asynchronous motor.

Description

technical field [0001] The invention relates to a method capable of detecting broken bar faults of a cage-type asynchronous motor rotor on-line, and belongs to the detection technical field. Background technique [0002] During the operation of the cage-type asynchronous motor, the rotor guide bars are subjected to alternating stresses such as radial electromagnetic force, rotating electromagnetic force, centrifugal force, thermal bending deflection force, etc., and rotor manufacturing defects may lead to broken bars. Such failures The probability of occurrence is about 15%. [0003] Broken rotor bars are a typical progressive fault. Usually one or two guide bars break at the initial stage, and then gradually develop until the output of the motor decreases or even shuts down. Therefore, on-line detection of broken rotor bars must be implemented. [0004] After the broken rotor bars of cage-type asynchronous motors occur, there will be The frequency of the additional curr...

AI Technical Summary

Problems solved by technology

In engineering practice, disturbances such as load fluctuations or noise are unavoidable. Too long signal acquisition time often means introducing these disturbances and affecting the results of Fourier spectrum analysis, and even worsening the performance of rotor broken bar fault detection, and even failure

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