An Accurate Fault Diagnosis Method for Bearings of Variable-speed Motors Based on Hall Signals
A technology of motor bearings and Hall signals, which is applied in the field of accurate fault diagnosis of motor bearings under variable speed conditions based on Hall signals, can solve problems such as the accuracy of speed measurement is not up to accurate fault diagnosis, and the angular resolution of Hall sensors is poor. Achieve the effect of low hardware cost and high reliability
Active Publication Date: 2020-11-24
ANHUI UNIVERSITY
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Problems solved by technology
However, the angular resolution of the Hall sensor is poor, and only a few speed pulses can be obtained for one revolution of the motor shaft. Under the condition of variable speed, the speed measurement accuracy it can provide is far from meeting the needs of accurate fault diagnosis.
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[0051] The present invention will be further described in detail below in conjunction with the accompanying drawings and simulated experimental data.
[0052] The periodic impact signal is selected as the single point fault simulation signal of the motor bearing, and its expression is:
[0053]
[0054] Among them, mod represents the remainder function, which is used to generate periodic shocks, A represents the amplitude of the signal, and f m Indicates the resonant frequency center of the bearing, f 0 Indicates the fault frequency of the bearing, and d=500 is the attenuation speed of the signal. In this simulation case, the values of the above four parameters are: A=1, f m = 1500Hz, f 0 =150Hz, d=500. The angular speed of the bearing is: y0(t)=425*t 3 -680*t 2 +260*t+59 (the unit is rad / s), the fault signal collected by it is x(t), the speed signal n(t) collected by the Hall sensor is fitted to y(t), and the sampling frequency of the signal is 10KHz. The signal ...
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The invention discloses a method for accurate fault diagnosis of motor bearings under variable speed conditions based on Hall signals, which includes: 1) performing polynomial fitting on the motor speed signals collected by Hall sensors to obtain a roughly estimated speed function; The polynomial coefficients of the rotational speed function obtained in the first step are optimized within a certain range. When optimizing, the rotational speed function determined by the polynomial is used to sample the fault signal at an equal angle, and the spectrum kurtosis of the obtained equiangular sampling signal is used as the optimization index. ; 3) The fault signal is sampled at equal angles by the optimal estimated speed function obtained in step 2), and the diagnosis conclusion is obtained through envelope spectrum analysis. This method is suitable for the variable speed fault diagnosis of the bearing of the Hall sensor installed or the motor that is inconvenient to install the encoder but can be installed with the Hall sensor. Compared with the traditional method, the anti-noise ability is better, and there is no need to install an additional encoder. Accurate fault diagnosis is realized.
Description
technical field [0001] The invention is applied to the technical field of precise fault diagnosis of motor bearings under variable speed conditions, and in particular relates to a precise fault diagnosis method for motor bearings under variable speed conditions based on Hall signals. Background technique [0002] The fault signal of the motor bearing (such as vibration, sound, etc.) contains a wealth of operating status information of the bearing, and the effective health monitoring and fault diagnosis of the motor bearing can be carried out through signal processing methods. Spectrum analysis is one of the common means of fault diagnosis, but frequency aliasing will occur in the frequency spectrum of the bearing fault signal of the motor under the condition of variable speed, which reduces the accuracy of the diagnosis result. At present, the main technical means to solve this problem is to perform equal-angle resampling on the fault signal, and the premise of equal-angle r...
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IPC IPC(8): G01M13/04
CPCG01M13/04
Inventor 刘方汪路李国丽王群京刘永斌陆思良琚斌曹正杨慧
Owner ANHUI UNIVERSITY