CN116502039A - A Frequency Domain Removal Method of Side Interference Signals Based on Motor Fault Diagnosis - Google Patents

Abstract

A bypass interference signal frequency domain removing method based on motor fault diagnosis comprises the following steps that S1, a tested motor is stopped, motor vibration signals in a stopped state are collected by using acquisition card equipment, and an interference signal y3 is obtained through storage; s2, starting the motor to be tested, collecting motor vibration signals by using a collection card device, and storing to obtain collected signals yn; s3, performing frequency domain analysis on the current acquired signal yn and the interference signal y3; s3-1, converting time domain signals of yn and y3 into frequency domain signals nn and n3 through Fourier transformation; s3-2, removing the n3 part in nn to obtain a frequency domain signal n1 of the normal signal; s3-3, converting the frequency domain signal n1 of the normal signal to obtain an original signal y1.

Description

A Frequency Domain Removal Method of Side Interference Signals Based on Motor Fault Diagnosis

technical field

The invention relates to the field of motor fault diagnosis, in particular to a method for removing side branch interference signals in the frequency domain based on motor fault diagnosis.

Background technique

When a motor fails, it is necessary to detect and collect the signal data of a motor, but when testing a motor, there will be multiple motors working together on site, and the vibration signals of other motors will interfere with the motor under test , causing the detection equipment to collect invalid signals, which cannot correctly reflect the real situation of the unit, which will bring confusion to the monitoring and analysis of the unit. If the effectiveness of the unit status signal is not checked, a large number of signals are too late for organization and management. , it will be difficult to give full play to the potential value of these signals, resulting in a waste of signal resources, and also put pressure on signal storage and maintenance, and affect the normal operation of the monitoring system.

Contents of the invention

The purpose of the present invention is to solve the shortcomings in the prior art, and propose a frequency domain removal method for side branch interference signals based on motor fault diagnosis; the.

In order to achieve the above object, the present invention adopts the following technical scheme: a frequency domain removal method for side branch interference signals based on motor fault diagnosis, comprising the following steps,

S1, the motor under test is stopped, and the vibration signal of the motor in the stopped state is collected by the acquisition card device, and the interference signal y3 is saved;

S2, start the motor under test, use the acquisition card device to collect the vibration signal of the motor, and save the collected signal yn;

S3, performing frequency domain analysis on the currently collected signal yn and the interference signal y3;

S3-1, converting the time-domain signals of yn and y3 into frequency-domain signals nn and n3 through Fourier transform;

S3-2, removing the n3 part in nn to obtain the frequency domain signal n1 of the normal signal;

S3-3. Convert the frequency domain signal n1 of the normal signal to obtain the original signal y1.

Preferably, the method of converting the frequency domain signal n1 in S3-3 into the original signal y1 can also be Laplace transform.

Compared with the prior art, the beneficial effect of the present invention is: the present invention converts time domain data and frequency domain data through Fourier transform calculation and Fourier inverse transform calculation, and then filters out invalid relevant data to obtain The effective frequency band and related data greatly reduce the interference of other motors on the site, improve the accuracy of data collection, check the validity of motor status signals, and give full play to the potential value of these signals.

Description of drawings

Fig. 1 is the time-domain diagram of acquisition signal in a kind of side branch interference signal frequency domain removal method based on motor fault diagnosis of the present invention;

Fig. 2 is the time-domain diagram of interference signal in a kind of side branch interference signal frequency domain removal method based on motor fault diagnosis of the present invention;

Fig. 3 is the frequency domain figure of acquisition signal in a kind of side branch interference signal frequency domain removal method based on motor fault diagnosis of the present invention;

Fig. 4 is the frequency domain figure of interference signal in a kind of side branch interference signal frequency domain removal method based on motor fault diagnosis of the present invention;

Fig. 5 is the frequency domain figure of original signal in a kind of side branch interference signal frequency domain removal method based on motor fault diagnosis of the present invention;

FIG. 6 is a time-domain diagram of the original signal in a frequency-domain removal method for side-branch interference signals based on motor fault diagnosis according to the present invention.

Detailed ways

In order to have a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed descriptions are provided in conjunction with the embodiments.

Please refer to Fig. 1, the frequency domain removal method of side branch interference signal based on motor fault diagnosis in an embodiment of the present invention, comprises the following steps:

S1, the motor under test is stopped, and the vibration signal of the motor in the stopped state is collected by the acquisition card device, and the interference signal y3 is saved;

S2, start the motor under test, use the acquisition card device to collect the vibration signal of the motor, and save the collected signal yn;

The acquisition card device is a vibration signal sensor, which is installed on the motor frame;

The acquisition card device collects the vibration signal of the motor, converts the vibration signal into an electrical signal, and obtains the time domain and frequency domain characteristics of the sound information by processing the electrical signal;

The time domain and frequency domain characteristics are the characteristics of the electrical signal itself;

The time-domain characteristic is to analyze the stability, transient and steady-state performance of the control system according to the time-domain expression of the output under a certain input. The independent variable in the time domain is time, that is, the horizontal axis is time, the vertical axis is the change of the signal, and its dynamic signal is a function that describes the value of the signal at different times;

The frequency domain characteristic is a coordinate system established when describing the characteristics of the signal in terms of frequency. The independent variable is the frequency, and the vertical axis is the amplitude of the frequency signal, that is, the spectrogram.

S3, perform frequency domain analysis on the currently collected signal yn and the interference signal y3, as shown in Figure 1-2;

S3-1, the time domain signals of yn and y3 are converted into frequency domain signals nn and n3 by Fourier transform, as shown in Figure 3-4;

Since the acquisition signal yn is a discrete signal, discrete Fourier transform and inverse Fourier transform are used;

Fourier transform formula:

S3-2, removing the n3 part in nn to obtain the frequency domain signal n1 of the normal signal;

S3-3. Convert the frequency domain signal n1 of the normal signal to obtain the original signal y1.

Inverse Fourier transform formula:

①②In the formula: X(k) represents the frequency domain signal value; x(n) represents the time domain signal value; j represents the complex number; n/N represents the time; 2πk represents the angular velocity;

Preferably, the method of converting the frequency domain signal n1 in S3-3 into the original signal y1 can also be Laplace transform.

The Laplace transform is a method of converting a time-domain signal into the "complex frequency domain".

The complex frequency domain is a linear ordinary differential equation in the time domain.

Laplace transform formula:

③ In the formula, F(s) is a function of complex variables, which transforms a function f(t) in the time domain into a complex variable function in the complex frequency domain, e ^-st is the convergence factor, and s=σ+jω is a complex number The frequency of the form is referred to as the complex frequency, where the real part of σ is always positive, and the imaginary part jω can be positive, negative or zero.

There are three parameters in the complex frequency domain, which must be represented by three-dimensional coordinates. When σ=0, it corresponds to the frequency domain, that is, the image of the surface corresponding to σ=0 in the three-dimensional diagram is the frequency domain diagram.

Claims (2)

1. A side branch interference signal frequency domain removal method based on motor fault diagnosis, is characterized in that: comprise the following steps, S1, the motor under test is stopped, and the vibration signal of the motor in the stopped state is collected by the acquisition card device, and the interference signal y3 is saved; S2, start the motor under test, use the acquisition card device to collect the vibration signal of the motor, and save the collected signal yn; S3, performing frequency domain analysis on the currently collected signal yn and the interference signal y3; S3-1, converting the time-domain signals of yn and y3 into frequency-domain signals nn and n3 through Fourier transform; S3-2, removing the n3 part in nn to obtain the frequency domain signal n1 of the normal signal; S3-3. Convert the frequency domain signal n1 of the normal signal to obtain the original signal y1. 2. The method for removing side branch interference signals in the frequency domain based on motor fault diagnosis as claimed in claim 1, characterized in that: the method of converting the frequency domain signal n1 into the original signal y1 in S3-3 can also be Laplace transform.