Rotating blade fault determination method, device and system and storage medium

Abstract

The invention discloses a method, a device and a system for determining a fault of a rotating blade, and a storage medium, which are used for improving the monitoring efficiency of the fault of the rotating blade. The method comprises the following steps: acquiring the rotating speed of a rotor in the rotary separator; calculating the rotor passing frequency of the rotary separator according to the rotating speed; matching the rotor passing frequency with a current frequency spectrum corresponding to a current signal of the rotary separator driving motor so as to determine the rotor passing frequency and a frequency point index of harmonic waves of the rotor passing frequency; extracting a corresponding amplitude in a current spectrum according to the frequency point index; calculating a total harmonic distortion rate corresponding to the current signal according to the amplitude; when the total harmonic distortion rate is larger than a preset threshold value, it is determined that the rotating blade breaks down. According to the scheme, the fault of the rotating blade can be monitored in real time according to the rotating speed of the rotor and the current signal, intrusive detection or regular shutdown inspection is avoided, and the monitoring efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of fault monitoring, and in particular to a method, device, system and storage medium for determining a rotating blade fault. Background Art

[0002] The medium-speed mill rotary separator (dynamic separator) is a key component in the pulverized coal preparation system. It houses an adjustable-speed rotor equipped with rotating blades. When the motor drives the separator at high speed (the speed is typically adjustable, ranging from approximately 50-300 rpm), an airflow carrying pulverized coal enters the separator from the mill outlet. The rotor drives the rotating blades, intercepting coarse particles due to their large mass and strong centrifugal force, and they fall back to the grinding disc for regrinding. Fine particles, due to their light mass, rise with the airflow and enter the boiler combustion system. Adjusting the rotor speed allows for flexible control of pulverized coal fineness: increasing the speed increases the centrifugal force, enhancing the separation efficiency, and resulting in finer pulverized coal; decreasing the speed decreases the centrifugal force, resulting in coarser pulverized coal.

[0003] Long-term operation of a rotary separator can lead to mechanical and corrosive wear, causing wear and deformation of the rotating blades. Long-term alternating loads can also cause fatigue fractures at the blade roots and blade shedding. Because the rotating blades are internal to the rotary separator system, existing technologies often rely on intrusive sensors or periodic shutdown inspections to detect blade wear or shedding, resulting in inefficient monitoring.

[0004] Therefore, how to provide a method for determining a rotating blade fault to improve the monitoring efficiency of the rotating blade fault. Summary of the Invention

[0005] The present application provides a method, device, system and storage medium for determining a rotating blade fault, so as to improve the monitoring efficiency of the rotating blade fault.

[0006] The present application provides a method for determining a rotating blade fault, comprising:

[0007] Obtain the rotational speed of the rotor in the rotating separator;

[0008] calculating a rotor passing frequency of the rotary separator based on the rotational speed;

[0009] Matching the rotor pass frequency with a current spectrum corresponding to a current signal of the rotating separator drive motor to determine a frequency index of the rotor pass frequency and its harmonics;

[0010] Extracting the corresponding amplitude in the current spectrum according to the frequency index;

[0011] Calculating the total harmonic distortion rate corresponding to the current signal according to the amplitude;

[0012] When the total harmonic distortion rate is greater than a preset threshold, it is determined that the rotary blade has failed.

[0013] The beneficial effects of the present application are as follows: obtaining the rotational speed of the rotor in a rotating separator; calculating the rotor pass frequency of the rotating separator based on the rotational speed; matching the rotor pass frequency with the current spectrum corresponding to the current signal of the rotating separator drive motor to determine the frequency index of the rotor pass frequency and its harmonics; extracting the corresponding amplitude in the current spectrum based on the frequency index; calculating the total harmonic distortion rate corresponding to the current signal based on the amplitude; and determining that a rotating blade fault has occurred when the total harmonic distortion rate is greater than a preset threshold. Since rotating blade faults can be monitored in real time based on the rotor speed and current signal, intrusive detection or periodic shutdown inspections are avoided, monitoring efficiency is improved, and monitoring costs are reduced.

[0014] In one embodiment, the calculating the rotor passing frequency of the rotating separator according to the rotational speed includes:

[0015] Substitute the rotational speed into the following formula to determine the rotor pass frequency of the rotary separator:

[0016]

[0017] Among them, f RPF is the rotor passing frequency (unit: Hz); RPM is the rotational speed (unit: revolutions per minute).

[0018] In one embodiment, the current spectrum corresponding to the current signal of the rotating separator driving motor is obtained by the following method:

[0019] Determine the minimum sampling rate of the current signal;

[0020] collecting the current signal according to the minimum sampling frequency;

[0021] performing preprocessing on the current signal, wherein the preprocessing includes at least detrending and Hanning window weighting;

[0022] The preprocessed current signal is subjected to fast Fourier transform (FFT) to obtain the corresponding current spectrum.

[0023] In one embodiment, determining the minimum sampling rate of the current signal includes:

[0024] Obtaining the maximum signal frequency and frequency resolution of the current signal;

[0025] The minimum sampling rate of the current signal is determined according to the maximum signal frequency and the frequency resolution.

[0026] In one embodiment, matching the rotor pass frequency with a current spectrum corresponding to a current signal of the rotating separator drive motor to determine a frequency index of the rotor pass frequency and its harmonics includes:

[0027] Determining a frequency that is an integer multiple of the rotor passing frequency as a target frequency;

[0028] Searching for a frequency point in the current spectrum whose difference from the target frequency is less than a preset frequency difference;

[0029] The frequency index is determined to be the frequency index of the rotor pass frequency and its harmonics.

[0030] In one embodiment, calculating the total harmonic distortion rate corresponding to the current signal according to the amplitude includes:

[0031] Substitute the amplitude into the following formula to calculate the total harmonic distortion rate corresponding to the current signal:

[0032]

[0033] Where THD is the total harmonic distortion corresponding to the current signal; h is the harmonic order (h = 1 for the fundamental frequency, h ≥ 2 for the harmonic); X[h] is the complex amplitude of the hth harmonic in the FFT spectrum; and H is the highest harmonic order.

[0034] In one embodiment, after determining that the rotary blade has failed, the method further includes:

[0035] Obtaining the rate of change and phase standard deviation of the amplitude of the frequency component current passing through the rotor;

[0036] When the rate of change of the current amplitude is greater than a first preset value or the phase standard deviation is greater than a second preset value, a blade fracture level 1 alarm is issued;

[0037] When the rate of change of the current amplitude is greater than a first preset value and the phase standard deviation is greater than a second preset value, a blade breakage level 2 alarm is issued.

[0038] In one embodiment, the method further comprises:

[0039] When the rate of change of the current amplitude is less than or equal to a first preset value and the phase standard deviation is less than or equal to a second preset value, a severe blade wear alarm is issued.

[0040] The present application also provides a device for determining a rotating blade fault, comprising:

[0041] A first acquisition module is used to acquire the rotational speed of the rotor in the rotary separator;

[0042] a first calculation module, configured to calculate a rotor passing frequency of the rotary separator according to the rotational speed;

[0043] A first determination module is configured to match the rotor pass frequency with a current spectrum corresponding to a current signal of the rotating separator drive motor to determine a frequency index of the rotor pass frequency and its harmonics;

[0044] An extraction module, configured to extract the corresponding amplitude in the current spectrum according to the frequency index;

[0045] A second calculation module is used to calculate the total harmonic distortion rate corresponding to the current signal according to the amplitude;

[0046] The second determining module is configured to determine that a fault occurs in the rotating blade when the total harmonic distortion rate is greater than a preset threshold.

[0047] In one embodiment, the first calculation module is further configured to:

[0048] Substitute the rotational speed into the following formula to determine the rotor pass frequency of the rotary separator:

[0049]

[0050] Among them, f RPF is the rotor passing frequency (unit: Hz); RPM is the rotational speed (unit: revolutions per minute).

[0051] In one embodiment, the current spectrum corresponding to the current signal of the rotating separator driving motor is obtained by the following method:

[0052] Determine the minimum sampling rate of the current signal;

[0053] collecting the current signal according to the minimum sampling frequency;

[0054] performing preprocessing on the current signal, wherein the preprocessing includes at least detrending and Hanning window weighting;

[0055] The preprocessed current signal is subjected to fast Fourier transform (FFT) to obtain the corresponding current spectrum.

[0056] In one embodiment, determining the minimum sampling rate of the current signal includes:

[0057] Obtaining the maximum signal frequency and frequency resolution of the current signal;

[0058] The minimum sampling rate of the current signal is determined according to the maximum signal frequency and the frequency resolution.

[0059] In one embodiment, the first determining module includes:

[0060] a first determining sub-module, configured to determine an integer multiple of the rotor passing frequency as a target frequency;

[0061] a searching sub-module, configured to search for a frequency point in the current frequency spectrum, which has a difference from the target frequency less than a preset frequency difference;

[0062] a second determining sub-module, configured to determine an index of the frequency point as an index of the frequency point of the rotor passing frequency and its harmonics.

[0063] In an embodiment, the second calculating module is further configured to:

[0064] substitute the amplitude into the following formula to calculate a total harmonic distortion rate of the current signal:

[0065]

[0066] wherein THD is the total harmonic distortion rate of the current signal; h is a harmonic order (h=1 is a fundamental frequency, and h≥2 is a harmonic); X[h] is a complex amplitude of the hth harmonic in the FFT frequency spectrum; and H is a highest harmonic order.

[0067] In an embodiment, the device further comprises:

[0068] a second acquiring module, configured to acquire a rate of change of the rotor passing frequency component current amplitude and a phase standard deviation;

[0069] a first alarm module, configured to issue a primary blade fracture alarm when the rate of change of the current amplitude is greater than a first preset value or the phase standard deviation is greater than a second preset value;

[0070] a second alarm module, configured to issue a secondary blade fracture alarm when the rate of change of the current amplitude is greater than the first preset value and the phase standard deviation is greater than the second preset value.

[0071] In an embodiment, the device further comprises:

[0072] a third alarm module, configured to issue a blade serious wear alarm when the rate of change of the current amplitude is less than or equal to the first preset value and the phase standard deviation is less than or equal to the second preset value.

[0073] The application also provides a rotating blade fault determination system, comprising:

[0074] at least one processor; and

[0075] a memory in communication connection with the at least one processor; wherein

[0076] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to implement the method for determining a rotating blade fault described in any one of the above embodiments.

[0077] The present application also provides a computer-readable storage medium. When the instructions in the storage medium are executed by a processor corresponding to the rotating blade fault determination system, the rotating blade fault determination system can implement the rotating blade fault determination method described in any of the above embodiments.

[0078] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. The purposes and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0079] The technical solution of the present application is further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings:

[0081] Figure 1 This is a flow chart of a method for determining a rotating blade fault in one embodiment of the present application;

[0082] Figure 2 This is a structural diagram of a device for determining a rotating blade fault in one embodiment of the present application;

[0083] Figure 3 Schematic diagram of the hardware structure of a system for determining a rotating blade fault in one embodiment of the present application. DETAILED DESCRIPTION

[0084] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application and are not used to limit the present application.

[0085] Rotating separator blade failures can cause periodic torque fluctuations (e.g., blade imbalance causing a sudden change in resistance with each revolution). This mechanical disturbance modulates the motor's stator current through magnetic coupling, generating characteristic sidebands and harmonic components (e.g., 50 Hz ± RPF) in the current spectrum, centered around the supply frequency and spaced at intervals around the rotor pass frequency (RPF). By monitoring the amplitude variations of these characteristic frequencies, the current characteristic spectrum of the rotating separator drive motor is analyzed to identify spectral features. A comprehensive analysis of the fundamental frequency, rotor pass frequency, harmonics, and high-frequency noise allows for more accurate identification of the fault type and location, thereby improving equipment reliability and maintenance efficiency and enabling non-invasive diagnosis of blade anomalies. Based on this, this proposal proposes a non-invasive, low-cost, and highly reliable online monitoring solution for blade wear. This solution provides early warning of faults by analyzing the motor current harmonic characteristics and total harmonic distortion (THD).

[0086] Figure 1 This is a flow chart of a method for determining a rotating blade fault in one embodiment of the present application. Figure 1 As shown, the method can be implemented as the following steps S101-S106:

[0087] In step S101, the rotation speed of the rotor in the rotary separator is obtained;

[0088] In step S102, a rotor passing frequency of the rotary separator is calculated according to the rotational speed;

[0089] In step S103, the rotor pass frequency is matched with a current spectrum corresponding to a current signal of the rotating separator drive motor to determine a frequency index of the rotor pass frequency and its harmonics;

[0090] In step S104, the corresponding amplitude in the current spectrum is extracted according to the frequency index;

[0091] In step S105, the total harmonic distortion rate corresponding to the current signal is calculated according to the amplitude;

[0092] In step S106 , when the total harmonic distortion rate is greater than a preset threshold, it is determined that a fault occurs in the rotary blade.

[0093] In this application, the rotational speed of the rotor in the rotating separator is obtained. For example, a high-precision rotational speed sensor can be used to capture the rotor's rotation information in real time, or some non-contact measurement technology, such as a laser velocimeter, can be used to accurately calculate the rotor's rotational speed by analyzing the Doppler shift of reflected light.

[0094] The rotor passing frequency of the rotating separator is calculated according to the rotating speed. The rotor passing frequency generally refers to the frequency at which the blade passes a fixed point per revolution of the rotor. Specifically, the rotating speed is substituted into the following formula to determine the rotor passing frequency of the rotating separator:

[0095]

[0096] wherein f RPF is the rotor passing frequency (unit: Hz); and RPM is the rotating speed (unit: revolutions per minute).

[0097] The rotor passing frequency is matched with the current spectrum corresponding to the current signal of the rotating separator driving motor to determine the frequency point index of the rotor passing frequency and its harmonics. Since the harmonic frequency is an integer multiple of the rotor passing frequency (RPF), the frequency point index k corresponding to f RPF , 2f RPF , 3f RPF is found in the frequency spectrum, and thus the harmonic component is determined.

[0098] To match the rotor passing frequency with the current spectrum corresponding to the current signal of the rotating separator driving motor, an integer multiple of the rotor passing frequency is determined as a target frequency. Then, the target frequency is matched with the current spectrum corresponding to the current signal of the rotating separator driving motor.

[0099] It should be noted that in an embodiment of the present application, the current spectrum corresponding to the current signal of the rotating separator driving motor is obtained by the following method:

[0100] First, the lowest sampling rate of the current signal is determined. In order to accurately analyze the signal, it is necessary to ensure that the highest signal frequency (including harmonics and high-frequency noise) is covered and the frequency resolution requirement is met. Therefore, the highest signal frequency and the frequency resolution of the current signal are obtained. The highest signal frequency represents the highest frequency component contained in the current signal. The input current signal can be carefully unfolded in the frequency domain using a spectrum analyzer to find the highest frequency point with a non-zero amplitude. The frequency value corresponding to this point is the highest signal frequency of the current signal. The frequency resolution can be determined in advance according to the analysis requirement.

[0101] In order to cover the highest signal frequency, the sampling frequency must satisfy the Nyquist sampling theorem. Therefore, based on the Nyquist sampling theorem, the first sampling frequency is determined according to the highest signal frequency of the current signal. Among them, the Nyquist sampling theorem (Nyquist Sampling Theorem) is the core theory in the field of signal processing, which points out that in order to restore the continuous signal without distortion, the sampling frequency must be at least twice the highest signal frequency. Therefore, the first sampling frequency is taken as 2 times the highest signal frequency. Of course, in order to cover potential high-frequency noise or higher harmonics, a margin can also be reserved. Therefore, the minimum sampling frequency in this application is greater than or equal to the first sampling frequency:

[0102] F S ≥F1=2×f max ;

[0103] Among them, F S is the lowest sampling frequency; F1 is the first sampling frequency; f max is the highest signal frequency.

[0104] Assuming the fundamental frequency is 50 Hz, the rotor pass frequency (RPF) is 50 Hz, the harmonic components are 100 Hz and 150 Hz, and the potential high-frequency noise is 300 Hz, then the highest signal frequency f max It is 300Hz. According to Nyquist sampling theorem, the minimum sampling rate Fs≥2×300Hz=600Hz.

[0105] Frequency resolution is the minimum interval that can distinguish two adjacent frequency components in spectrum analysis (such as fast Fourier transform FFT). For example, if Δf = 1 Hz, it is impossible to distinguish between 100 Hz and 101 Hz signals. Therefore, the second sampling frequency is determined according to the predetermined frequency resolution:

[0106] F S ≥F2=Δf×N;

[0107] Where Fs represents the minimum sampling rate; F2 is the second sampling frequency; Δf is the sampling resolution; and N is the number of sampling points of the fast Fourier transform.

[0108] If it is necessary to distinguish between the rotor passing frequency (RPF=50 Hz) and the interference frequency (such as 50.5 Hz), then Δf≤0.5 Hz. If the number of FFT points N=1024, then Fs≥Δf×N=0.5×1024=512 Hz.

[0109] Taking into account the Nyquist sampling theorem and frequency resolution, the maximum of the first sampling frequency and the second sampling frequency is taken as the minimum sampling frequency. For example, in the above example, the minimum sampling rate can be max(600Hz, 512Hz)=600Hz.

[0110] Secondly, the current signal is collected according to the minimum sampling frequency. By installing a Hall current sensor (such as LEM LA-55P) on the power line of the rotating separator motor, the current signal of the rotating separator driving motor is collected according to the minimum sampling frequency.

[0111] Then, the current signal is preprocessed, wherein the preprocessing includes at least detrending and Hanning window weighting. In order to eliminate interference, suppress spectrum leakage and improve analysis accuracy, the present application performs detrending and Hanning window weighting on the collected current signal.

[0112] (1) Detrending of current signals

[0113] The main purpose of current signal detrending is to remove DC offset and suppress low-frequency interference. DC offset refers to baseline drift caused by slow changes in sensor bias or load. Suppressing low-frequency interference removes slow-changing trends other than the power frequency (such as thermal drift) to prevent them from contaminating the low-frequency spectrum.

[0114] The detrending formula for sampled data is:

[0115]

[0116] Among them, x detrend [n] is the detrended signal value; x[n] is the instantaneous value of the signal at discrete time point n, which is the nth sampling point of the original signal; N is the length of the signal segment (total number of sampling points).

[0117] This formula eliminates DC offsets by subtracting the mean of the signal segment, providing a standardized signal for subsequent spectral analysis. Parameter N controls the range of mean calculation and directly impacts detrending effectiveness and real-time performance. In rotating separator monitoring, combining Hanning window weighting with FFT can significantly improve the detection sensitivity of fault characteristic frequencies.

[0118] (2) Hanning window weighting of current signal

[0119] While real signals are typically infinite in length, FFT analysis requires truncation of a finite length (e.g., N sampling points). Direct signal truncation is equivalent to multiplying the signal by a rectangular window (i.e., abrupt truncation), resulting in sidelobe leakage in the spectrum. Sidelobes can mask the true components of adjacent frequencies. Especially when multiple frequency components exist in a signal, sidelobes can interfere with each other, causing spectral distortion.

[0120] The Hanning Window is a window function commonly used in signal processing. Its shape is a raised cosine function. It gradually attenuates at both ends of the signal, making the truncation edge smoother, thereby reducing high-frequency glitches. This means that the energy leaking to adjacent frequencies is greatly reduced, and the spectrum is cleaner. By smoothing the beginning and end of the signal, the signal edge is smoother when truncation occurs, reducing the introduction of high-frequency components caused by sudden truncation. Hanning window weighting can suppress spectrum leakage and improve frequency resolution. Suppressing spectrum leakage means reducing the energy diffusion caused by signal truncation and making the spectrum peak sharper. Improving frequency resolution means reducing sidelobe interference by smoothing the signal edges. The time domain expression of the Hanning window is:

[0121]

[0122] Where w[n] is the weight value of the Hanning window function at the nth sampling point, and its value range is 0≤w[n]≤1. It is used to weight the signal so that both ends of the signal smoothly transition to zero and reduce spectrum leakage. 0.5 represents the normalization coefficient, which ensures that the maximum amplitude of the window function is 1. Indicates that the cosine function generates the window shape and controls the distribution of weights, which is used to form a smooth bell-shaped curve with the weights being zero at n=0 and n=N-1 and gradually increasing to the maximum value in the middle; n is the index of the current sampling point; N is the window length (total number of sampling points).

[0123] After windowing:

[0124] x windowed [n] = x detrend [n]·W[n];

[0125] Among them, x windowed [n] is the value of the windowed signal at the nth sampling point, which is the time-domain weighted signal; x detrend [n] is the signal value after detrending; w[n] is the weight value of the Hanning window function at the nth sampling point.

[0126] Then, the pre-processed current signal is subjected to a fast Fourier transform (FFT) to obtain the corresponding current spectrum. First, the pre-processed current signal is subjected to an FFT calculation to obtain a complex spectrum X[k], where k = 0, 1, ..., N-1. The specific formula is as follows:

[0127]

[0128] Among them, X[k] is the complex spectrum corresponding to the kth frequency point; x windowed[n] is the value of the windowed signal at the nth sampling point; n is the time domain index, that is, the sequence number of the time domain sampling point (n = 0, 1, ..., N-1); k is the frequency domain index, the frequency point sequence number (k = 0, 1, ..., N-1), and the corresponding frequency is N is the number of sampling points, that is, the window length of FFT transformation (such as 1024 points); j is the imaginary unit; e -j2πkn / N is the rotation factor, the complex basis function, which projects the time domain signal into the frequency domain.

[0129] Secondly, the amplitude spectrum is calculated, and the FFT result is modulo and normalized. The specific formula is:

[0130] The FFT output is a complex number representing the quadrature components of the signal at frequency k:

[0131] X[k]=Re(X[k])+jIm(X[k])

[0132] Compute the magnitude of a complex number:

[0133]

[0134] Taking the modulus of the FFT result and normalizing it (taking into account the compensation of the energy loss of the Hanning window, the Hanning window is multiplied by 0.5N, so here it is multiplied by 2 / N), we get:

[0135]

[0136] After that, the frequency axis mapping calculation is performed, the formula is:

[0137]

[0138] Among them, f k is the actual frequency corresponding to the kth frequency point (unit: Hz); k is the frequency domain index, the frequency point number; F s represents the minimum sampling rate in Hz; N represents the number of sampling points, that is, the window length of the FFT transform.

[0139] Then, the amplitude and frequency of each k index are obtained.

[0140] When performing spectrum analysis on a signal, the spectrum analyzer divides the signal's frequency range into a series of discrete frequency points (i.e., frequency bins). Because the actual frequency may not fall precisely on a frequency bin, in one embodiment of the present application, a frequency bin is searched in the current spectrum for which the difference from the target frequency is less than a preset frequency difference. The index of the frequency bin is determined to be the frequency bin index of the rotor pass frequency and its harmonics.

[0141] According to the frequency index, the corresponding amplitude in the current spectrum is extracted. For example, |X[k]| is directly read through the index k. For example, f RPF= 20 Hz and Δf = 1.95 Hz, then k is approximately 10 (20 / 1.95 = 10.26, rounded to 10).

[0142] In another embodiment of the present application, when the actual frequency does not exactly fall on the frequency point, the amplitude information of the frequency point closest to the actual frequency is determined; the amplitude at the actual frequency is calculated according to the amplitude information of the adjacent frequency points by using an interpolation method, so as to improve the accuracy of frequency analysis. Common interpolation methods include linear interpolation, quadratic interpolation, etc. Then, the amplitude is converted into a current value according to the sensitivity of the sensor (such as 1 V / A). For example, if |X[k]| = 0.5 V, then the current amplitude is 50 A.

[0143] According to the amplitude, the total harmonic distortion rate corresponding to the current signal is calculated. Specifically, the amplitude is substituted into the following formula to calculate the total harmonic distortion rate corresponding to the current signal:

[0144]

[0145] wherein THD is the total harmonic distortion rate corresponding to the current signal; h is the harmonic order (h = 1 is the fundamental frequency, and h ≥ 2 is the harmonic); X[h] is the complex amplitude of the hth harmonic in the FFT spectrum; and H is the highest harmonic order.

[0146] When the total harmonic distortion rate is greater than a preset threshold, it is determined that the rotating blade is faulty.

[0147] Further, blade wear and blade shedding are common fault types in rotating separators, both of which can cause rotor imbalance and thus induce vibration. However, their fault mechanisms and manifestations are not the same. For blade wear, blade wear occurs gradually, leading to uneven distribution of blade mass but no reduction in the number of blades. Due to the mass imbalance, 1 × RPF frequency and its harmonics are mainly excited, and the amplitude of RPF and its harmonics can be increased due to the aerodynamic imbalance caused by blade wear. In the frequency spectrum, the amplitude of 1 × RPF (rotational frequency) and its harmonics (2 ×, 3 × RPF) is increased.

[0148] For blade shedding, a certain blade is completely or partially shed, leading to a sudden and significant change in rotor mass and a serious destruction of dynamic balance. Due to the serious mass loss, the vibration amplitude is significantly increased, especially at the 1 × RPF frequency. Higher harmonics or impact components can be excited, especially if the shedding causes a transient impact on the rotor. In the frequency spectrum, the amplitude of 1 × RPF is sharply increased, possibly accompanied by high amplitudes of 2 × and 3 × RPF.

[0149] There are differences in the frequency spectrum between blade wear and blade breakage. The commonality is that both will cause an increase in the 1×RPF frequency amplitude, and the amplitude of the harmonic frequencies (2× and 3×RPF) may also increase. The difference between the two is that, first, the 1×RPF harmonic frequency amplitude of blade wear increases more slowly, usually on a weekly or monthly basis, whereas blade breakage and shedding usually occur instantaneously, with the 1×RPF amplitude increasing rapidly and dramatically. Therefore, the main way to determine whether it is wear or shedding is to monitor the 1×RPF variation characteristics. Second, the phase characteristics are different. In the case of blade wear, the vibration phase (mainly determined by 1×RPF) is relatively stable; in the case of blade shedding, a sudden phase change may occur (mainly determined by 1×RPF). In this way, blade wear and breakage can be determined by phase judgment.

[0150] Therefore, in one embodiment of the present application, after determining that a fault has occurred in the rotating blade, the rate of change of the amplitude of the frequency component current passing through the rotor and the phase standard deviation are obtained;

[0151] (1) The rate of change of the rotor current amplitude through the frequency component

[0152] For the 1×RPF frequency component amplitude sequence |X1[t]| extracted by FFT, the rate of change of the rotor current amplitude through the frequency component is calculated by the time domain difference method:

[0153]

[0154] Where |X1[t]| represents the amplitude of the frequency component passed by the rotor at time t, in A; |X1[t-1]| represents the amplitude of the frequency component passed by the rotor at time t-1, in A; ΔA[t] represents the output change rate, in A / s; Δt represents the time interval between adjacent time windows (usually equal to the FFT sampling rate).

[0155] (2) Phase standard deviation of the rotor current amplitude through the frequency component:

[0156] The complex spectrum X[k] output by FFT contains both amplitude and phase information:

[0157] X[k]=Re(X[k])+j·Im(X[k])

[0158] The phase calculation formula is:

[0159]

[0160] Where φ[k] represents the phase at frequency k.

[0161] Since the phase difference φ(t) of 1×RPF (rotor passing frequency) remains stable, that is,

[0162]

[0163] Therefore, to quantify the phase stability, the phase standard deviation in the sliding window is calculated:

[0164]

[0165] where σ φ is the phase standard deviation of the rotor passing frequency component current amplitude; φ[k] represents the phase of the frequency point i; μ φ is the phase average of the rotor passing frequency component current amplitude.

[0166] Further, it can be judged that when the current amplitude change rate is greater than a first preset value or the phase standard deviation is greater than a second preset value, a first-level blade fracture alarm is issued; wherein the first preset value and the second preset value can be determined in advance according to historical data or artificial experience. In an embodiment of the present application, the first preset value is 3 times the historical standard deviation of the rotor passing frequency component current amplitude change rate. Specifically,

[0167] The historical standard deviation of ΔA[t] is calculated:

[0168]

[0169] where σ is the historical standard deviation of the rotor passing frequency component current amplitude change rate, and μ ΔA represents the historical change rate average of the rotor passing frequency component current amplitude change rate.

[0170] Since under normal distribution, 99.7% of the data falls within μ±3σ, exceeding this range is considered abnormal.

[0171] Therefore, the first preset value is determined to be 3σ, and when |ΔA[t]|>3σ occurs, it can be judged that the blade is fractured.

[0172] In addition, the second preset value can be taken according to the corresponding value according to specific requirements. For example, when the value is 10, if σ φ >10, it indicates that the phase produces a large fluctuation.

[0173] Of course, when the current amplitude change rate is greater than the first preset value and the phase standard deviation is greater than the second preset value, a second-level blade fracture alarm is issued.

[0174] When the total harmonic distortion rate is greater than the preset threshold, but the current amplitude change rate is less than or equal to the first preset value and the phase standard deviation is less than or equal to the second preset value, a blade serious wear alarm is issued.

[0175] In summary, this application achieves monitoring through motor current signal analysis, improving monitoring efficiency and eliminating the need to install sensors inside the separator, which is subject to high temperature and high dust. This avoids equipment modification and maintenance downtime, significantly reducing system deployment costs. In addition, after determining whether a fault has occurred based on the total harmonic distortion rate, a dual algorithm of amplitude mutation and phase jump is integrated to perform multi-level response, significantly reducing the false alarm rate and significantly reducing false alarms compared to single vibration monitoring.

[0176] The beneficial effects of the present application are as follows: obtaining the rotational speed of the rotor in a rotating separator; calculating the rotor pass frequency of the rotating separator based on the rotational speed; matching the rotor pass frequency with the current spectrum corresponding to the current signal of the rotating separator drive motor to determine the frequency index of the rotor pass frequency and its harmonics; extracting the corresponding amplitude in the current spectrum based on the frequency index; calculating the total harmonic distortion rate corresponding to the current signal based on the amplitude; and determining that a rotating blade fault has occurred when the total harmonic distortion rate is greater than a preset threshold. Since rotating blade faults can be monitored in real time based on the rotor speed and current signal, intrusive detection or periodic shutdown inspections are avoided, monitoring efficiency is improved, and monitoring costs are reduced.

[0177] In one embodiment, the above step S102 may be implemented as follows:

[0178] Substitute the rotational speed into the following formula to determine the rotor pass frequency of the rotary separator:

[0179]

[0180] Among them, f RPF is the rotor passing frequency; RPM is the rotor speed.

[0181] In one embodiment, the current spectrum corresponding to the current signal of the rotating separator driving motor is obtained by the following steps A1-A4:

[0182] In step A1, the minimum sampling rate of the current signal is determined;

[0183] In step A2, the current signal is collected according to the minimum sampling frequency;

[0184] In step A3, preprocessing is performed on the current signal, wherein the preprocessing at least includes detrending and Hanning window weighting;

[0185] In step A4, a fast Fourier transform (FFT) is performed on the preprocessed current signal to obtain a corresponding current spectrum.

[0186] In one embodiment, the above step A1 may be implemented as the following steps A11-A12:

[0187] In step A11, the highest signal frequency and frequency resolution of the current signal are obtained;

[0188] In step A12, the lowest sampling rate of the current signal is determined according to the highest signal frequency and frequency resolution.

[0189] In one embodiment, the above step S103 can be implemented as steps B1-B3 as follows:

[0190] In step B1, an integer multiple of the rotor passing frequency is determined as a target frequency;

[0191] In step B2, a frequency point in the current frequency spectrum is searched, which has a difference from the target frequency less than a preset frequency difference;

[0192] In step B3, an index of the frequency point is determined as the frequency point index of the rotor passing frequency and its harmonics.

[0193] In one embodiment, the above step S105 can be implemented as steps as follows:

[0194] The amplitude is substituted into the following formula to calculate the total harmonic distortion rate of the current signal:

[0195]

[0196] wherein THD is the total harmonic distortion rate of the current signal; h is the harmonic order (h=1 is the fundamental frequency, and h≥2 is the harmonic); X[h] is the complex amplitude of the hth harmonic in the FFT frequency spectrum; and H is the highest harmonic order.

[0197] In one embodiment, after step S106, the method can be further implemented as steps C1-C3 as follows:

[0198] In step C1, the rate of change of the rotor passing frequency component current amplitude and the phase standard deviation are obtained;

[0199] In step C2, when the rate of change of the current amplitude is greater than a first preset value or the phase standard deviation is greater than a second preset value, a primary blade fracture alarm is issued;

[0200] In step C3, when the rate of change of the current amplitude is greater than the first preset value and the phase standard deviation is greater than the second preset value, a secondary blade fracture alarm is issued.

[0201] In one embodiment, the method can be further implemented as step C4 as follows:

[0202] In step C4, when the rate of change of the current amplitude is less than or equal to the first preset value and the phase standard deviation is less than or equal to the second preset value, a blade serious wear alarm is issued.

[0203] Figure 2 FIG. 1 is a structural diagram of a device for determining a rotating blade fault in an embodiment of the present application. Figure 2 Shown, including:

[0204] A first acquisition module 201 is used to acquire the rotational speed of the rotor in the rotary separator;

[0205] A first calculation module 202 is configured to calculate a rotor passing frequency of the rotary separator according to the rotational speed;

[0206] A first determination module 203 is configured to match the rotor pass frequency with a current spectrum corresponding to a current signal of the rotating separator drive motor to determine a frequency index of the rotor pass frequency and its harmonics;

[0207] An extraction module 204 is configured to extract the corresponding amplitude in the current spectrum according to the frequency index;

[0208] A second calculation module 205 is configured to calculate the total harmonic distortion rate corresponding to the current signal according to the amplitude;

[0209] The second determining module 206 is configured to determine that a fault occurs in the rotating blade when the total harmonic distortion rate is greater than a preset threshold.

[0210] In one embodiment, the first calculation module is further configured to:

[0211] Substitute the rotational speed into the following formula to determine the rotor pass frequency of the rotary separator:

[0212]

[0213] Among them, f RPF is the rotor passing frequency; RPM is the rotor speed.

[0214] In one embodiment, the current spectrum corresponding to the current signal of the rotating separator driving motor is obtained by the following method:

[0215] Determine the minimum sampling rate of the current signal;

[0216] collecting the current signal according to the minimum sampling frequency;

[0217] performing preprocessing on the current signal, wherein the preprocessing includes at least detrending and Hanning window weighting;

[0218] The preprocessed current signal is subjected to fast Fourier transform (FFT) to obtain the corresponding current spectrum.

[0219] In one embodiment, determining the minimum sampling rate of the current signal includes:

[0220] Obtaining the maximum signal frequency and frequency resolution of the current signal;

[0221] The minimum sampling rate of the current signal is determined according to the maximum signal frequency and the frequency resolution.

[0222] In one embodiment, the first determining module includes:

[0223] A first determining submodule, configured to determine a frequency that is an integer multiple of the rotor passing frequency as a target frequency;

[0224] a search submodule, configured to search in the current spectrum for a frequency point whose difference from the target frequency is less than a preset frequency difference;

[0225] The second determining submodule is configured to determine the frequency index as the frequency index of the rotor passing frequency and its harmonics.

[0226] In one embodiment, the second calculation module is further configured to:

[0227] Substitute the amplitude into the following formula to calculate the total harmonic distortion rate corresponding to the current signal:

[0228]

[0229] Where THD is the total harmonic distortion corresponding to the current signal; h is the harmonic order (h = 1 for the fundamental frequency, h ≥ 2 for the harmonic); X[h] is the complex amplitude of the hth harmonic in the FFT spectrum; and H is the highest harmonic order.

[0230] In one embodiment, the apparatus further comprises:

[0231] A second acquisition module is used to obtain the rate of change and phase standard deviation of the rotor current amplitude of the frequency component;

[0232] a first alarm module, configured to issue a blade fracture level 1 alarm when the rate of change of the current amplitude is greater than a first preset value or the phase standard deviation is greater than a second preset value;

[0233] The second alarm module is configured to issue a blade breakage secondary alarm when the rate of change of the current amplitude is greater than a first preset value and the phase standard deviation is greater than a second preset value.

[0234] In one embodiment, the apparatus further comprises:

[0235] The third alarm module is configured to issue a severe blade wear alarm when the rate of change of the current amplitude is less than or equal to a first preset value and the phase standard deviation is less than or equal to a second preset value.

[0236] Figure 3 FIG. 1 is a schematic diagram of the hardware structure of a system for determining a rotating blade fault in an embodiment of the present application. Figure 3 As shown, the system for determining a rotating blade fault includes:

[0237] at least one processor 320; and,

[0238] A memory 304 in communication with the at least one processor 320; wherein,

[0239] The memory 304 stores instructions that can be executed by the at least one processor 320 . The instructions are executed by the at least one processor 320 to implement the method for determining a rotating blade fault described in any of the above embodiments.

[0240] Reference Figure 3 The rotating blade fault determination system 300 may include one or more of the following components: a processing component 302 , a memory 304 , a power supply component 306 , a multimedia component 308 , an audio component 310 , an input / output (I / O) interface 312 , a sensor component 314 , and a communication component 316 .

[0241] Processing component 302 generally controls the overall operation of rotor blade fault determination system 300. Processing component 302 may include one or more processors 320 to execute instructions to perform all or part of the steps of the method described above. Furthermore, processing component 302 may include one or more modules to facilitate interaction between processing component 302 and other components. For example, processing component 302 may include a multimedia module to facilitate interaction between multimedia component 308 and processing component 302.

[0242] The memory 304 is configured to store various types of data to support the operation of the rotating blade fault determination system 300. Examples of such data include instructions for any application or method operating on the rotating blade fault determination system 300, such as text, images, videos, etc. The memory 304 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disk.

[0243] Power supply assembly 306 provides power to various components of rotating blade failure determination system 300. Power supply assembly 306 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to rotating blade failure determination system 300.

[0244] The multimedia component 308 includes a screen that provides an output interface between the rotor blade failure determination system 300 and a user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touches, slides, and gestures on the touch panel. The touch sensors can not only sense the boundaries of a touch or slide action, but also detect the duration and pressure associated with the touch or slide action. In some embodiments, the multimedia component 308 may also include a front camera and / or a rear camera. When the rotor blade failure determination system 300 is in an operating mode, such as a capture mode or a video mode, the front camera and / or the rear camera can receive external multimedia data. Each front camera and the rear camera can have a fixed optical lens system or have a focal length and optical zoom capability.

[0245] Audio component 310 is configured to output and / or input audio signals. For example, audio component 310 includes a microphone (MIC) configured to receive external audio signals when rotor blade fault determination system 300 is in an operating mode, such as alarm mode, recording mode, voice recognition mode, or voice output mode. The received audio signals may be further stored in memory 304 or transmitted via communication component 316. In some embodiments, audio component 310 also includes a speaker for outputting audio signals.

[0246] I / O interface 312 provides an interface between processing component 302 and peripheral interface modules, such as a keyboard, click wheel, buttons, etc. These buttons may include but are not limited to: a home button, volume buttons, a start button, and a lock button.

[0247] The sensor assembly 314 includes one or more sensors for providing various aspects of status evaluation for the rotating blade fault determination system 300. For example, the sensor assembly 314 can include a sound sensor. In addition, the sensor assembly 314 can detect an on / off status of the rotating blade fault determination system 300, relative positioning of components, such as a display and keypad of the rotating blade fault determination system 300, the sensor assembly 314 can also detect an operational status of the rotating blade fault determination system 300 or a component of the rotating blade fault determination system 300, such as an operational status of an air distribution plate, a structural status, an operational status of a material discharge blade, etc., an orientation or acceleration / deceleration of the rotating blade fault determination system 300, and a temperature change of the rotating blade fault determination system 300. The sensor assembly 314 can include a proximity sensor configured to detect the presence of a nearby object without any physical contact. The sensor assembly 314 can also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 314 can also include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, a material pile thickness sensor, or a temperature sensor.

[0248] The communication assembly 316 is configured to enable the rotating blade fault determination system 300 to provide wired or wireless communication capabilities with other devices and cloud platforms. The rotating blade fault determination system 300 can access a wireless network based on a communication standard, such as WiFi, 2G or 3G, or a combination thereof. In an example embodiment, the communication assembly 316 receives a broadcast signal or broadcast-related information from an external broadcast management system via a broadcast channel. In an example embodiment, the communication assembly 316 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra wideband (UWB) technology, Bluetooth (BT) technology, and other technologies.

[0249] In an example embodiment, the rotating blade fault determination system 300 can be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, micro-controllers, microprocessors, or other electronic elements for executing the rotating blade fault determination method as described in any of the embodiments above.

[0250] The present application also provides a computer-readable storage medium, when instructions in the storage medium are executed by a processor corresponding to the rotating blade fault determination system, the rotating blade fault determination system is enabled to implement the rotating blade fault determination method as described in any of the embodiments above.

[0251] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) that contain computer-usable program code.

[0252] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0253] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0254] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0255] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for determining a rotating blade fault, characterized in that: include: Obtain the rotational speed of the rotor in the rotating separator; calculating a rotor passing frequency of the rotary separator based on the rotational speed; Matching the rotor pass frequency with a current spectrum corresponding to a current signal of the rotating separator drive motor to determine a frequency index of the rotor pass frequency and its harmonics; Extracting the corresponding amplitude in the current spectrum according to the frequency index; Calculating the total harmonic distortion rate corresponding to the current signal according to the amplitude; When the total harmonic distortion rate is greater than a preset threshold, it is determined that the rotary blade has failed.

2. The method according to claim 1, wherein The current spectrum corresponding to the current signal of the rotating separator driving motor is obtained by the following method: Determine the minimum sampling rate of the current signal; collecting the current signal according to the minimum sampling frequency; performing preprocessing on the current signal, wherein the preprocessing includes at least detrending and Hanning window weighting; The preprocessed current signal is subjected to fast Fourier transform (FFT) to obtain the corresponding current spectrum.

3. The method according to claim 2, wherein The determining of the minimum sampling rate of the current signal comprises: Obtaining the maximum signal frequency and frequency resolution of the current signal; The minimum sampling rate of the current signal is determined according to the maximum signal frequency and the frequency resolution.

4. The method according to claim 1, wherein The matching of the rotor pass frequency with a current spectrum corresponding to a current signal of the rotating separator driving motor to determine a frequency index of the rotor pass frequency and its harmonics includes: Determining a frequency that is an integer multiple of the rotor passing frequency as a target frequency; Searching for a frequency point in the current spectrum whose difference from the target frequency is less than a preset frequency difference; The frequency index is determined to be the frequency index of the rotor pass frequency and its harmonics.

5. The method according to claim 1, wherein Calculating the total harmonic distortion rate corresponding to the current signal according to the amplitude includes: Substitute the amplitude into the following formula to calculate the total harmonic distortion rate corresponding to the current signal: Where THD is the total harmonic distortion corresponding to the current signal; h is the harmonic order (h = 1 for the fundamental frequency, h ≥ 2 for the harmonic); X[h] is the complex amplitude of the hth harmonic in the FFT spectrum; and H is the highest harmonic order.

6. The method according to claim 1, wherein After determining that the rotary blade has failed, the method further includes: Obtaining the rate of change and phase standard deviation of the current amplitude of the rotor passing frequency component; When the rate of change of the current amplitude is greater than a first preset value or the phase standard deviation is greater than a second preset value, a blade fracture level 1 alarm is issued; When the rate of change of the current amplitude is greater than a first preset value and the phase standard deviation is greater than a second preset value, a blade breakage level 2 alarm is issued.

7. The method according to claim 6, wherein The method further comprises: When the rate of change of the current amplitude is less than or equal to a first preset value and the phase standard deviation is less than or equal to a second preset value, a severe blade wear alarm is issued.

8. A device for determining a rotating blade fault, characterized in that: include: A first acquisition module is used to acquire the rotational speed of the rotor in the rotary separator; a first calculation module, configured to calculate a rotor passing frequency of the rotary separator according to the rotational speed; A first determination module is configured to match the rotor pass frequency with a current spectrum corresponding to a current signal of the rotating separator drive motor to determine a frequency index of the rotor pass frequency and its harmonics; An extraction module, configured to extract the corresponding amplitude in the current spectrum according to the frequency index; A second calculation module is used to calculate the total harmonic distortion rate corresponding to the current signal according to the amplitude; The second determining module is configured to determine that a fault occurs in the rotating blade when the total harmonic distortion rate is greater than a preset threshold.

9. A system for determining a rotating blade fault, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to implement the method for determining a rotary blade fault according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that When the instructions in the storage medium are executed by a processor corresponding to the rotating blade fault determination system, the rotating blade fault determination system can implement the rotating blade fault determination method according to any one of claims 1 to 7.

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