A fault detection method for cage-type asynchronous motor rotor broken bars based on esprit and psa

Abstract

The invention discloses a cage asynchronous motor rotor broken-bar fault detection method based on an electronic stability program rotation invariant technology (ESPRIT) and a pattern search algorithm (PSA). The method comprises the following steps of: performing a rotation invariant technology on a stator current instant signal acquired according to a certain frequency so as to obtain accurate frequency values, rough amplitude values and rough initial phase angles of a fundamental wave component and a side frequency component; estimating the accurate amplitude values and the accurate initial phase angles of the fundamental wave component and the side frequency component of the stator current instant signal by applying a pattern search algorithm, and thus obtaining a ratio, which is used as a fault characteristic, of the amplitude value of the current side frequency component to the amplitude value of the fundamental wave component; calculating a ratio of the ratio to a detection threshold value to determine a fault index; and finally determining whether a broken-bar fault exists or not according to the fault index. By the method, the asynchronous motor rotor broken-bar fault can be detected on line with high sensitivity and high reliability by using a small number of stator current signal sampling points; therefore, the influence caused by adverse factors such as load fluctuation, noise and the like can be overcome effectively; and the method is extremely applicable to low slip-ratio running situations of an 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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