A method, system, medium and device for detecting and regulating the asymmetric operation of a fan blade

Abstract

The invention discloses a method, system, medium and device for detecting and regulating the asymmetric operation of a fan blade. The method judges according to the 1P frequency component of the acceleration signal in the front-back direction of the nacelle, and measures in real time the lidar ranging values between the tip parts of the three blades and the fan nacelle when the impeller azimuth angles are 0°, 120°, and 240° respectively as the three blades pass by the tower barrel. According to the distribution of the lidar ranging values of the three blades, a comparison judgment is made with a preset threshold. An angle compensation value is added or subtracted from the pitch angle setting value of the blade corresponding to the lidar ranging value being too small or too large until the 1P frequency component of the acceleration signal in the front-back direction of the fan nacelle is lower than the preset threshold. The invention can quickly locate the asymmetric operation caused by the stiffness difference between the three blades of the fan, and greatly reduce the frequent pitch angle adjustment actions of the blades caused by the small clearance between the tip parts of the blades and the tower barrel due to the small blade stiffness.

Description

Technical Field

[0001] The present invention relates to the technical field of fan control systems, and in particular to a method, system, medium and device for detecting and regulating the asymmetric operation of fan blades. Background Art

[0002] For onshore high-power wind turbines, during the continuous increase of blade length, the blade weight shows a gradually decreasing trend, and the blade deformation increases continuously due to the reduced stiffness; on the one hand, it is difficult to ensure the stiffness consistency of long blades of the same model from the process; on the other hand, the annual installation scale of wind turbines is very large, and the delivery cycle of components including blades is short, which further increases the difficulty of long blade process control; with various factors superimposed, finally, the stiffness differences between the three blades installed on the same fan are relatively large.

[0003] During the grid-connected power generation process of the fan, it is easy to generate a 1P signal with a frequency of 1 times the impeller rotation frequency in signals such as nacelle acceleration, generator speed, and blade angle; the existence of the 1P frequency signal will, on the one hand, cause a significant increase in the fatigue load of the tower operation, and on the other hand, the blade with small stiffness will frequently trigger the pitch action of increasing the blade angle due to the small clearance between the blade tip and the tower, resulting in a large loss of power generation of the wind turbine and also affecting the service life of the pitch actuator. Summary of the Invention

[0004] The first object of the present invention is to provide a method for detecting and regulating the asymmetric operation of fan blades to solve the deficiencies in the prior art, which can simply and quickly locate the asymmetric operation caused by the stiffness difference between the three blades of the fan, and at the same time regulate the asymmetric operation, greatly reducing the frequent pitch actions of increasing the blade angle caused by the small clearance between the blade tip part with small blade stiffness and the tower.

[0005] The second object of the present invention is to provide a system for detecting and regulating the asymmetric operation of fan blades.

[0006] The third object of the present invention is to provide a non-transitory computer-readable medium.

[0007] The fourth object of the present invention is to provide a computing device.

[0008] The first object of the present invention is achieved by the following technical solutions: A method for detecting and regulating the asymmetric operation of fan blades includes the following steps:

[0009] S1. Obtain the original acceleration signal in the fore-aft direction of the nacelle of the wind turbine, filter the original acceleration signal in the fore-aft direction of the nacelle through a dynamic 1P frequency notch filter with the rotation frequency corresponding to the real-time rotational speed filtering value of the wind turbine as the center frequency, subtract the acceleration signal in the fore-aft direction of the nacelle after being filtered by the dynamic 1P frequency notch filter from the original acceleration signal in the fore-aft direction of the nacelle to obtain the 1P frequency component of the acceleration signal in the fore-aft direction of the nacelle;

[0010] S2. When the 1P frequency component of the acceleration signal in the fore-aft direction of the nacelle is not less than a preset threshold, for the three blades of the wind turbine, when the absolute value encoder built in the wind turbine measures the impeller azimuth angles to be 0°, 120°, and 240° respectively in real time, use the lidar rangefinder to obtain the distances between the tip parts of the three blades and the nacelle of the wind turbine when the three blades pass by the tower barrel respectively, that is, the lidar ranging values of each blade;

[0011] S3. According to the statistical distribution of the lidar ranging values of each blade, compare the occurrence times of the lidar ranging values of each blade being less than the preset protection threshold plus the preset distance. If the occurrence times are greater than the preset number threshold, increase a preset angle compensation value for the pitch angle given value of the blade corresponding to the lidar ranging value being less than the preset protection threshold plus the preset distance, otherwise decrease a preset angle compensation value for the pitch angle given value of the blade corresponding to the lidar ranging value being greater than the preset protection threshold plus the preset distance;

[0012] S4. Repeat the above steps S1 to S3 until the 1P frequency component of the acceleration signal in the fore-aft direction of the nacelle of the wind turbine is lower than the preset threshold, and complete the detection and regulation of the asymmetric operation of the wind turbine blades.

[0013] Further, in step S2, the following operations are specifically performed:

[0014] When the 1P frequency component of the acceleration signal in the fore-aft direction of the nacelle is not less than a preset threshold, for the three blades with the initial installation azimuth angles of 0°, 120°, and 240° of the wind turbine respectively, when the absolute value encoder built in the wind turbine measures the impeller azimuth angles to be 0°, 120°, and 240° respectively in real time, use the lidar rangefinder built on the nacelle of the wind turbine to obtain the distances between the tip parts of the three blades and the nacelle of the wind turbine when the three blades pass by the tower barrel respectively, that is, the lidar ranging values of each blade.

[0015] Further, in step S3, the following operations are specifically performed:

[0016] According to the statistical distribution of the lidar ranging values of each blade, compare the occurrence times of each lidar ranging value being less than the preset protection threshold plus the preset distance. If the occurrence times are greater than the preset number threshold, it means that the blade corresponding to the lidar ranging value less than the preset protection threshold plus the preset distance has low stiffness and large deformation. On the contrary, it means that the blade corresponding to the lidar ranging value greater than the preset protection threshold plus the preset distance has high stiffness and small deformation. Add a preset angle compensation value to the pitch angle set value of the blade with low stiffness and large deformation, and subtract a preset angle compensation value from the pitch angle set value of the blade with high stiffness and small deformation.

[0017] The second object of the present invention is achieved by the following technical solution: A wind turbine blade asymmetric operation detection and regulation system, comprising:

[0018] A nacelle front-back direction acceleration signal acquisition module, used to acquire the original nacelle front-back direction acceleration signal of the wind turbine;

[0019] A dynamic 1P frequency notch filtering module, used to filter the original nacelle front-back direction acceleration signal;

[0020] An impeller azimuth angle acquisition module, used to measure the real-time impeller azimuth angle of the blade with the initial installation azimuth angle of 0° of the wind turbine;

[0021] A lidar ranging module, used to measure the distance between the tip of each blade of the wind turbine and the nacelle when the blade passes through the tower barrel;

[0022] A blade stiffness and deformation judgment module, according to the statistical distribution of the lidar ranging values of each blade, compare the occurrence times of each blade's lidar ranging value being less than the preset protection threshold plus the preset distance. If the occurrence times are greater than the preset number threshold, it means that the blade corresponding to the lidar ranging value less than the preset protection threshold plus the preset distance has low stiffness and large deformation. On the contrary, it means that the blade corresponding to the lidar ranging value greater than the preset protection threshold plus the preset distance has high stiffness and small deformation;

[0023] An angle compensation module, used to add a preset angle compensation value to the pitch angle set value of the blade with low stiffness and large deformation, and subtract a preset angle compensation value from the pitch angle set value of the blade with high stiffness and small deformation.

[0024] The third object of the present invention is achieved by the following technical solution: A non-transitory computer-readable medium storing instructions, when the instructions are executed by a processor, perform the steps of the above-mentioned wind turbine blade asymmetric operation detection and regulation method.

[0025] The fourth object of the present invention is achieved by the following technical solution: A computing device includes a processor and a memory for storing programs executable by the processor. When the processor executes the programs stored in the memory, the above-mentioned method for detecting and regulating the asymmetric operation of the fan blades is implemented.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] The present invention is simple and can quickly locate the asymmetric operation caused by the stiffness difference between the three blades of the wind turbine, greatly reducing the frequent pitch angle change actions of the blades due to the small stiffness of the blades, resulting in a small clearance between the blade tip and the tower barrel. On the one hand, it reduces the power generation loss of the fan, on the other hand, it avoids shortening the design life of the pitch actuator, and at the same time avoids the fatigue of the tower barrel during the power generation mode and a significant increase in the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a time series diagram of the original acceleration signal in the front-back direction of the nacelle before filtering and the 1P frequency component time series diagram of the acceleration signal in the front-back direction of the nacelle after filtering.

[0029] Figure 2 It is the signal spectrum of the original acceleration signal in the front-back direction of the nacelle.

[0030] Figure 3 It is the signal spectrum diagram of the My bending moment measured at the bottom of the tower barrel before the pitch angle given value compensation of the blade.

[0031] Figure 4 It is the statistical distribution diagram of the lidar ranging values of the three blades of the fan in the power generation mode.

[0032] Figure 5 It is the signal spectrum diagram of the My bending moment measured at the bottom of the tower barrel after the pitch angle given value compensation of the blade. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present invention will be further described below with reference to specific embodiments.

[0034] Embodiment 1

[0035] Refer to Figures 1 to 5 As shown, the method for detecting and regulating the asymmetric operation of the fan blades provided in this embodiment includes the following steps:

[0036] S1. Obtain the original acceleration signal in the fore-aft direction of the nacelle of the wind turbine. Filter the original acceleration signal in the fore-aft direction of the nacelle through a dynamic 1P frequency notch filter with the rotation frequency corresponding to the real-time rotation speed filtering value of the wind turbine as the center frequency. Subtract the acceleration signal in the fore-aft direction of the nacelle after being filtered by the dynamic 1P frequency notch filter from the original acceleration signal in the fore-aft direction of the nacelle to obtain the 1P frequency component of the acceleration signal in the fore-aft direction of the nacelle;

[0037] S2. When the 1P frequency component of the acceleration signal in the fore-aft direction of the nacelle is not less than a preset threshold, for the three blades of the wind turbine, when the absolute value encoder built in the wind turbine measures the impeller azimuth angles as 0°, 120°, and 240° in real time, obtain the distances between the tip parts of the three blades and the nacelle of the wind turbine when the three blades pass by the tower barrel respectively through a lidar rangefinder, that is, the lidar ranging values of each blade. Specifically, perform the following operations:

[0038] Before compensating the pitch angle set value of the blade, the measured My bending moment spectrum in the fore-aft direction at the bottom of the tower barrel is dominated by 1P frequency and 2P frequency signals; when the 1P frequency component of the acceleration signal in the fore-aft direction of the nacelle is not less than a preset threshold, for the three blades with the initial installation azimuth angles of 0°, 120°, and 240° of the wind turbine respectively, when the absolute value encoder built in the wind turbine measures the impeller azimuth angles as 0°, 120°, and 240° in real time, obtain the distances between the tip parts of the three blades and the nacelle of the wind turbine when the three blades pass by the tower barrel respectively through the lidar rangefinder built on the nacelle of the wind turbine, that is, the lidar ranging values of each blade. According to the statistical distribution of the lidar ranging values when the three blades of the wind turbine pass by the tower barrel in turn in the power generation mode, among which when the lidar ranging values of the three blades exceed 100 meters, it means that when the blade passes by the tower barrel, the tip part of the blade is far from the tower barrel, and the laser beam does not irradiate the tip of the blade. At this time, the lidar ranging value is the distance where the laser beam irradiates the ground. When the lidar ranging value is lower than 85 meters, it means that when the three blades pass by the tower barrel, the lidar ranging value is the measured distance where the laser beam irradiates the tip part of the blade, reflecting that the tip part of the corresponding blade is deformed greatly and the blade stiffness is small; the blade with the initial impeller azimuth angle of 120° has the smallest blade stiffness, and the number of times the lidar ranging value is less than 85 meters far exceeds that of the other two blades; for the blade with the initial impeller azimuth angle of 0°, the lidar ranging value is less than 85 meters only occurs five times, and the blade stiffness is moderate; for the blade with the initial impeller azimuth angle of 240°, the lidar ranging value does not occur less than 85 meters, and the blade stiffness is the largest.

[0039] S3. According to the statistical distribution of the lidar ranging values of each blade, compare the occurrence times of the lidar ranging values of each blade being less than the preset protection threshold plus the preset distance. If the occurrence times are greater than the preset number threshold, increase a preset angle compensation value for the pitch angle set value of the blade corresponding to the lidar ranging value being less than the preset protection threshold plus the preset distance; otherwise, decrease a preset angle compensation value for the pitch angle set value of the blade corresponding to the lidar ranging value being greater than the preset protection threshold plus the preset distance. Specifically, perform the following operations:

[0040] According to the statistical distribution of the lidar ranging values of each blade, compare the occurrence times of each lidar ranging value being less than the preset clearance protection threshold plus a 20-meter distance. If the occurrence times are greater than the preset number threshold, it indicates that the blade corresponding to the lidar ranging value being less than the preset protection threshold plus a 20-meter distance has low stiffness and large deformation; otherwise, it indicates that the blade corresponding to the lidar ranging value being greater than the preset protection threshold plus a 20-meter distance has high stiffness and small deformation. Increase a preset angle compensation value for the pitch angle set value of the blade with low stiffness and large deformation, and decrease a preset angle compensation value for the pitch angle set value of the blade with high stiffness and small deformation. The setting of the angle compensation value is obtained by looking up a table in the relationship table between the occurrence times and the angle compensation value; after compensation, the attenuation amplitudes of the 1P frequency and 2P frequency signals in the measured My moment spectrum in the front-back direction at the bottom of the tower are large, and the 1P frequency and 2P frequency signals are no longer the dominant ones, but the signals with frequencies below 0.1 Hz are dominant, and the energy of the frequency components below 0.1 Hz is much smaller than Figure 3 the 1P and 2P frequency components in it, thereby avoiding a large increase in the running fatigue load of the My moment in the front-back direction at the bottom of the tower and ensuring the safe and reliable operation of the wind turbine.

[0041] S4. Repeat the above steps S1 to S3 until the 1P frequency component of the acceleration signal in the front-back direction of the nacelle of the wind turbine is lower than the preset threshold, and complete the detection and regulation of the asymmetric operation of the wind turbine blades.

[0042] Embodiment 2

[0043] This embodiment discloses a detection and regulation system for the asymmetric operation of wind turbine blades, including:

[0044] An acceleration signal acquisition module in the front-back direction of the nacelle, which is used to acquire the original acceleration signal in the front-back direction of the nacelle of the wind turbine;

[0045] A dynamic 1P frequency notch filter module, which is used to filter the original acceleration signal in the front-back direction of the nacelle;

[0046] An impeller azimuth angle acquisition module, which is used to measure the real-time impeller azimuth angle of the blade with an initial installation azimuth angle of 0° of the wind turbine;

[0047] The lidar ranging module is used to measure the distance between the tip of each blade of the wind turbine and the nacelle of the wind turbine when each blade passes through the tower barrel.

[0048] The blade stiffness and deformation judgment module, according to the statistical distribution of the lidar ranging values of each blade, compares the number of occurrences where the lidar ranging value of each blade is less than the preset protection threshold plus the preset distance. If the number of occurrences is greater than the preset number threshold, it means that the blade corresponding to the lidar ranging value less than the preset protection threshold plus the preset distance has small stiffness and large deformation. On the contrary, it means that the blade corresponding to the lidar ranging value greater than the preset protection threshold plus the preset distance has large stiffness and small deformation.

[0049] The angle compensation module is used to increase a preset angle compensation value for the pitch angle given value of the blade with small stiffness and large deformation, and decrease a preset angle compensation value for the pitch angle given value of the blade with large stiffness and small deformation.

[0050] Embodiment 3

[0051] This embodiment discloses a non-transitory computer-readable medium storing instructions, which, when executed by a processor, perform the steps of the method for detecting and regulating the asymmetric operation of the wind turbine blades according to Embodiment 1.

[0052] The non-transitory computer-readable medium in this embodiment may be a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a USB flash drive, a mobile hard disk, or other media.

[0053] Embodiment 4

[0054] This embodiment discloses a computing device, including a processor and a memory for storing the executable program of the processor. When the processor executes the program stored in the memory, the method for detecting and regulating the asymmetric operation of the wind turbine blades according to Embodiment 1 is implemented.

[0055] The computing device described in this embodiment may be an embedded host, a desktop computer, a laptop computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with processor functions.

[0056] The above-described embodiments are only the preferred embodiments of the present invention, and do not limit the scope of implementation of the present invention. Therefore, any changes made according to the shape and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for detecting and regulating the asymmetric operation of a fan blade, characterized in that, Including the following steps: S1. Obtain the original acceleration signal in the front-back direction of the nacelle of the wind turbine, filter the original acceleration signal in the front-back direction of the nacelle through a dynamic 1P frequency notch filter with the rotation frequency corresponding to the real-time rotational speed filtering value of the wind turbine as the center frequency, subtract the acceleration signal in the front-back direction of the nacelle after being filtered by the dynamic 1P frequency notch filter from the original acceleration signal in the front-back direction of the nacelle to obtain the 1P frequency component of the acceleration signal in the front-back direction of the nacelle; S2. When the 1P frequency component of the acceleration signal in the front-back direction of the nacelle is not less than a preset threshold, for the three blades of the wind turbine, when the absolute value encoder built in the wind turbine measures the impeller azimuth angles to be 0°, 120°, and 240° respectively in real time, use the lidar rangefinder to obtain the distances between the tip parts of the three blades and the nacelle of the wind turbine when the three blades pass by the tower barrel respectively, that is, the lidar ranging values of each blade; S3. According to the statistical distribution of the lidar ranging values of each blade, compare the occurrence times of the lidar ranging values of each blade being less than the preset protection threshold plus the preset distance. If the occurrence times are greater than the preset number threshold, increase a preset angle compensation value for the pitch angle given value of the blade corresponding to the lidar ranging value being less than the preset protection threshold plus the preset distance, and vice versa, decrease a preset angle compensation value for the pitch angle given value of the blade corresponding to the lidar ranging value being greater than the preset protection threshold plus the preset distance; S4. Repeat the above steps S1 to S3 until the 1P frequency component of the acceleration signal in the front-back direction of the nacelle of the wind turbine is lower than the preset threshold, and complete the detection and regulation of the asymmetric operation of the wind turbine blades.

2. The method for detecting and regulating the asymmetric operation of a fan blade according to claim 1, characterized in that, In step S2, the following operations are specifically performed: When the 1P frequency component of the acceleration signal in the front-back direction of the nacelle is not less than a preset threshold, for the three blades with the initial installation azimuth angles of 0°, 120°, and 240° of the wind turbine respectively, when the absolute value encoder built in the wind turbine measures the impeller azimuth angles to be 0°, 120°, and 240° respectively in real time, use the lidar rangefinder built on the nacelle of the wind turbine to obtain the distances between the tip parts of the three blades and the nacelle of the wind turbine when the three blades pass by the tower barrel respectively, that is, the lidar ranging values of each blade.

3. The method for detecting and regulating the asymmetric operation of a fan blade according to claim 1, characterized in that, In step S3, the following operations are specifically performed: According to the statistical distribution of the lidar ranging values of each blade, compare the occurrence times of each lidar ranging value being less than the preset protection threshold plus the preset distance. If the occurrence times are greater than the preset number threshold, it means that the blade corresponding to the lidar ranging value being less than the preset protection threshold plus the preset distance has a small stiffness and large deformation, and vice versa, it means that the blade corresponding to the lidar ranging value being greater than the preset protection threshold plus the preset distance has a large stiffness and small deformation. Increase a preset angle compensation value for the pitch angle given value of the blade with small stiffness and large deformation, and decrease a preset angle compensation value for the pitch angle given value of the blade with large stiffness and small deformation.

4. A system for detecting and regulating the asymmetric operation of a fan blade, characterized in that, Including: An acceleration signal acquisition module in the front-back direction of the nacelle, which is used to obtain the original acceleration signal in the front-back direction of the nacelle of the wind turbine; A dynamic 1P frequency notch filtering module, which is used to filter the original acceleration signal in the front-back direction of the nacelle; An impeller azimuth angle acquisition module, which is used to measure the real-time impeller azimuth angle of the blade with the initial installation azimuth angle of the fan being 0°; A lidar ranging module, which is used to measure the distance between the tip of each blade of the fan and the fan nacelle when each blade passes by the tower barrel; A blade stiffness and deformation judgment module, which statistically analyzes the distribution of the lidar ranging values of each blade, compares the number of occurrences where the lidar ranging value of each blade is less than the preset protection threshold plus the preset distance. If the number of occurrences is greater than the preset number threshold, it means that the blade corresponding to the lidar ranging value less than the preset protection threshold plus the preset distance has small stiffness and large deformation. Otherwise, it means that the blade corresponding to the lidar ranging value greater than the preset protection threshold plus the preset distance has large stiffness and small deformation; An angle compensation module, which is used to increase a preset angle compensation value for the pitch angle set value of the blade with small stiffness and large deformation, and decrease a preset angle compensation value for the pitch angle set value of the blade with large stiffness and small deformation.

5. A non - transitory computer - readable medium storing instructions, characterized in that, When the instruction is executed by the processor, the steps of the fan blade asymmetric operation detection and regulation method according to claims 1-3 are executed.

6. A computing device, including a processor and a memory for storing processor - executable programs, characterized in that, When the processor executes the program stored in the memory, the fan blade asymmetric operation detection and regulation method according to claims 1-3 is implemented.

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