A method for improving the wind deflection accuracy of a wind turbine generator set
Through the analysis of the current spectrum of the pitch motor of the wind turbine and the construction of the wind direction-power curve data table, the impeller rotation plane is dynamically adjusted, which solves the problem of inaccurate measurement of wind direction angle of the wind turbine, and achieves high-precision wind control and improves the The power generation power is reduced and the load is reduced.
Patent Information
- Application Number
- CN202410874035.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-02
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2044-07-02
AI Technical Summary
There is inaccuracy in the measurement of wind direction angles in wind turbines, resulting in a decrease in power generation power and an increase in load. The existing technology such as lidar wind meter is costly and cannot be applied on a large scale, and the dynamic response of statistical analysis methods is poor.
By collecting the working current of the pitch motor for spectrum analysis, we can determine whether there is a deviation between the impeller rotation plane and the incoming wind direction, build a wind direction-power curve data table, and dynamically adjust the impeller rotation plane to improve wind response and achieve rapid response.
Without adding hardware equipment, the wind direction angle measurement accuracy of wind turbine units is improved, the power generation power is increased in real time, and the loads of blades, bolts and towers are reduced, avoiding the problem of wind direction measurement error and high lidar cost.
Smart Images
Figure CN118622581B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of wind power generation, and in particular to a method for improving the wind deflection accuracy of a wind power generator set. Background Art
[0002] In wind power generation, a key factor affecting the power generation and operating load of a wind turbine is the wind angle. When a wind turbine is not operating directly in the direction of the incoming wind, the power generation of the turbine will be reduced and the load on the turbine will increase to a certain extent.
[0003] In order to solve the above technical problems, the wind turbine generator set in the prior art needs to be able to accurately measure the wind direction angle when it is in operation. When the wind direction angle deviates, the yaw system is used to rotate the cabin to perform automatic wind-facing operations.
[0004] like Figure 1 As shown, wind turbines mainly use wind vanes to monitor wind direction angles, and in order to facilitate installation and not affect the normal operation of the impeller, the wind vane can only be installed downwind of the impeller. The originally uniform incoming wind flow will become a chaotic rotating wake wind flow after passing through the rotating impeller, which will cause disturbances to the wind vane, resulting in inaccurate wind direction angle data being measured. At the same time, when a mechanical wind vane is installed, there may also be errors in installation accuracy and inadequate subsequent operation and maintenance, resulting in inaccurate actual wind direction angle detection data. Therefore, in the actual operation of a wind turbine, it is common for the power generation to be reduced and the load to be increased due to inaccurate wind.
[0005] like Figure 2 As shown, in order to solve the technical problem of inaccurate wind direction detection by traditional mechanical wind vanes, the existing technology uses a laser radar anemometer device to measure the wind direction angle of the incoming wind in front of the impeller by emitting lasers. Since it will not be affected by the wake of the impeller, the actual wind direction angle of the incoming wind in front of the impeller can be measured with high precision. However, the price of the laser radar wind vane is very high, which makes it impossible to use it on a large scale.
[0006] In addition, the prior art also performs yaw calibration through an algorithm based on the statistics of the unit's operating data. The yaw calibration algorithms are all statistical algorithms related to the wind direction angle of the unit. By statistically analyzing a large amount of wind direction angle and operating data such as power and wind speed, a strong correlation curve of the wind direction angle is obtained, and the average yaw error is evaluated to perform yaw calibration on the unit's wind angle. Although the above algorithm can evaluate the yaw error to a certain extent, the statistical data is based on the measurement data of the wind vane, and the measurement of the wind vane is affected by the wake of the rotating impeller, and the error is large. The results obtained by analyzing the data with large errors also have large corresponding errors. In addition, the use of statistical analysis methods requires the analysis of long-term operating data, and cannot quickly determine the wind direction deviation. The dynamic response is poor and can only be used for static deviation calibration. Summary of the invention
[0007] The main purpose of the present invention is to address the deficiencies in the prior art methods for accurately controlling wind direction of wind turbines, and to propose a method for improving the accuracy of wind direction of wind turbines. The method can improve the accuracy of wind direction angle measurement of wind turbines without adding any hardware equipment, thereby increasing the power generation capacity of wind turbines in real time and reducing the load on blades, bolts and towers of wind turbines.
[0008] To achieve the above object, the present invention proposes a method for improving the wind direction accuracy of a wind turbine generator set, comprising the following steps:
[0009] Step S1: collecting the working current driven by the pitch motor within a certain period of time, performing spectrum analysis on the current data of the pitch motor of the blade within a certain period of time, analyzing the frequency and amplitude of the blade load cycle signal, and judging whether there is a deviation between the central axis of the impeller rotation plane and the wind direction of the incoming wind;
[0010] Step S2: construct a wind direction-power curve data table through power, wind direction angle, and wind speed;
[0011] Step S3: calibrate the wind reference line, divide the wind speed into several wind speed intervals according to the wind speed value calibrated on the wind reference line, and calibrate the power curve of the maximum wind speed value in the wind speed interval;
[0012] Step S4: dynamically detect the incoming wind speed, select the power curve corresponding to the wind speed range, and compare the maximum power point of the same power curve with the standard wind direction angle facing the wind reference line, set the adjustment direction according to the positive or negative value of the difference, set the adjustment angle according to the absolute value of the difference, and adjust the angle between the central axis of the impeller rotation plane and the incoming wind direction;
[0013] Step S5: When the yaw system swings to a corresponding angle, the working current recording data of the pitch motor is updated, and the above steps S1-S4 are re-executed. When the amplitude value corresponding to the periodic signal is less than the amplitude threshold, the corresponding angle adjustment is stopped.
[0014] Preferably, in step S1, according to the changing law of the pitch motor current, the first half cycle is divided into the first time, and the second half cycle is divided into the second time, and the corresponding phase current values are compared by the pitch motor current curve of the first half cycle and the pitch motor current curve of the second half cycle; or by superimposing and comparing the current change trajectories; or by comparing the maximum current value of the first half cycle with the maximum current value of the second half cycle.
[0015] Preferably, the current changes in the first half cycle and the second half cycle are evaluated by subtracting the maximum current values of the pitch motor current in the first half cycle and the second half cycle. If the absolute value of the difference obtained by subtraction is less than or equal to the above-mentioned current change threshold, it can be considered that the pitch motor current has not fluctuated significantly; if the absolute value of the difference between the two maximum current values is greater than the current change threshold, it can be considered that the pitch motor current has fluctuated significantly.
[0016] Preferably, in step S1, Fourier transform is performed on the variable pitch motor current to obtain a current spectrum of the variable pitch motor, and the amplitude value corresponding to the changed impeller rotation frequency is obtained by searching for the impeller rotation frequency at which the load cycle signal changes within a specified frequency range, and the amplitude value is compared with a preset amplitude threshold.
[0017] Preferably, if the amplitude value corresponding to the impeller rotation frequency when the load cycle signal changes is less than or equal to the amplitude threshold, the impeller rotation plane is perpendicular to the incoming wind direction; if the amplitude value corresponding to the impeller rotation frequency when the load cycle signal changes is greater than the amplitude threshold, the impeller rotation plane is not perpendicular to the incoming wind direction.
[0018] Preferably, in step S2, 180° is used as the standard wind direction angle, and a wind reference line is set in the vertical direction of the standard wind direction angle, with the wind direction angle on the left side being less than 180° and the wind direction angle on the right side being greater than 180°.
[0019] Preferably, in step S3, according to the location of the wind turbine and the historical working data collected and counted, power curves corresponding to different wind speeds are obtained, and each power curve arranged along the left and right directions has a maximum power point with the largest value. The maximum power points of the power curves corresponding to different wind speeds are connected longitudinally in sequence to obtain the maximum power line.
[0020] Preferably, in step S4, the wind direction angle corresponding to the maximum power point of the current wind speed is subtracted from the standard wind direction angle of 180°. If a positive value is obtained, it means that the wind direction angle corresponding to the maximum power point at this time is greater than 180°, the maximum power point is located on the right side of the wind reference line, the incoming wind is a right-biased wind, and the absolute value of the difference is the angle that the yaw system needs to swing to the right.
[0021] Preferably, in step S4, according to the wind direction deviation trend of the current wind turbine, the average value point is obtained with the upper and lower wind speed values corresponding to the current wind speed, and the midpoint between the maximum power points corresponding to the upper and lower wind speed values and located on the maximum power line is extracted. The line connecting the average value point and the midpoint is used as the first line, and a second line is made with the current wind speed as the starting point, and the second line is parallel to the first line. The point where the second line and the maximum power line first intersect is the maximum power point of the real-time wind speed.
[0022] The technical solution of the present invention has the following advantages over the prior art:
[0023] The technical solution of the present invention can quickly and accurately reflect the characteristics of blade load changes when the unit has wind deviations by using variable pitch motor current detection, identify and give a wind direction angle deviation, and then determine the wind deviation direction by power maximum analysis. The wind direction angle is calibrated by the deviation amount and deviation direction to achieve the purpose of facing the wind. The technical solution of the present invention can effectively make up for the large error of wind direction angle data currently measured by wind vanes and the high cost of using laser radar anemometers. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.
[0025] Figure 1 The schematic diagram of the prior art using a wind vane to measure wind direction;
[0026] Figure 2 The schematic diagram of the prior art using a laser radar side wind instrument to measure wind direction;
[0027] Figure 3 This is a working principle diagram of the embodiment of the present invention in the windward working condition;
[0028] Figure 4 This is a working principle diagram of an embodiment of the present invention in a non-directly facing wind condition;
[0029] Figure 5 This is a graph showing the current variation of the pitch motor when the wind is directly facing the impeller according to an embodiment of the present invention;
[0030] Figure 6 This is a frequency spectrum diagram of the variable pitch motor current after Fourier transformation when the wind is directly facing the impeller in an embodiment of the present invention;
[0031] Figure 7 This is a graph showing the current variation of the pitch motor when the wind force is not directly directed toward the impeller according to an embodiment of the present invention;
[0032] Figure 8 This is a frequency spectrum diagram after Fourier transformation of the current of the pitch motor when the wind force is not directly facing the impeller in an embodiment of the present invention;
[0033] Fig. 9 A relationship diagram between wind direction deviation and power maximum value according to an embodiment of the present invention;
[0034] Fig.10 A relationship diagram of power-wind direction angle-wind speed according to an embodiment of the present invention;
[0035] Fig.11 The present invention is a flowchart of a method for improving the wind direction accuracy of a wind turbine generator set.
[0036] Description of Figure Numbers:
[0037] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0039] See also Figures 1 to 11 The present invention proposes a method for improving the wind direction accuracy of a wind turbine generator set.
[0040] See also Figure 3 The load on the impeller of a wind turbine generator set is mainly the lift on the blades, and the lift on the blades mainly depends on the blade's angle of attack and / or relative wind speed. When the impeller's rotation plane is facing the incoming wind, that is, the wind direction of the incoming wind is perpendicular to the impeller's rotation plane, the incoming wind at this time only produces an axial inflow component to the central axis of the impeller, and the wind speed remains unchanged relative to the wind speed of the impeller, and the blades will not generate vibration or loads in other directions during rotation.
[0041] See also Figure 4 When there is a wind direction deviation, the incoming wind direction is no longer perpendicular to the impeller's rotation plane, that is, there is an angle between the incoming wind direction and the central axis of the impeller. The force exerted by the incoming wind on the impeller can be decomposed into an axial component that coincides with the central axis of the impeller's rotation plane and a radial component parallel to the impeller's rotation plane. Due to the presence of the radial component of the incoming wind, when the impeller blades rotate, the relative wind speed of the blades changes periodically in sync with the impeller speed, causing the load on the blades to change periodically, which is directly reflected in the current change of the pitch motor.
[0042] In the method of improving the wind deflection accuracy of a wind turbine generator set of the present invention, when the incoming wind acting on the impeller rotation plane has a radial component, that is, the wind force of the incoming wind is not perpendicular to the impeller rotation plane, the load borne by the blades changes periodically during the actual operation of the blades. The radial component of the wind force will cause the pitch motor to be not in the optimal working state, and the working current of the pitch motor will also change periodically.
[0043] The technical solution of the present invention collects the working current of the pitch motor within a certain period of time, and can perform spectrum analysis on the current data of the pitch motor of a single blade within the above-mentioned time, analyze the frequency and amplitude value of the blade load cycle signal, and determine whether there is a deviation between the central axis of the impeller rotation plane and the wind direction of the incoming wind.
[0044] like Figure 5 As shown in the figure, when the impeller rotation plane is perpendicular to the wind force, that is, when the fan is facing the incoming wind, the yaw system set inside the wind turbine does not need to rotate the cabin to adjust the impeller rotation plane to be perpendicular to the incoming wind. The blades are not subjected to radial wind force, and the pitch motor does not need to adjust the working angle of the blades. The entire wind turbine is in the best working state. At this time, the output current waveform of the pitch motor changes in a relatively stable pattern. The pitch motor current does not show obvious deviation in the front and back half cycles. The amplitude value corresponding to the impeller rotation frequency of the load cycle signal obtained by Fourier transform is small.
[0045] Preferably, within the above-mentioned detection time, according to the changing law of the pitch motor current, the first half cycle is divided into the first time and the second half cycle is divided into the second time, and the corresponding phase current values are compared between the pitch motor current curve in the first half cycle and the pitch motor current curve in the second half cycle, or the current change trajectories are overlapped and compared, or the maximum current value in the first half cycle is compared with the maximum current value in the second half cycle to evaluate the current change situation in the first half cycle and the second half cycle, or the current change threshold is set, and the maximum current values of the pitch motor current in the first half cycle and the second half cycle are subtracted. If the absolute value of the difference obtained by subtraction is less than or equal to the above-mentioned current change threshold, it can be considered that the pitch motor current has not experienced large fluctuations.
[0046] like Figure 6 As shown, the above-mentioned variable pitch motor current is subjected to Fourier transform to obtain the variable pitch motor current spectrum, and the amplitude value corresponding to the changed impeller rotation frequency is obtained by searching for the impeller rotation frequency where the load cycle signal changes within the specified frequency range, and the amplitude value is compared with the preset amplitude threshold value. If the amplitude value corresponding to the impeller rotation frequency where the load cycle signal changes is less than or equal to the amplitude threshold value, it can be considered that the impeller rotation plane at this time is perpendicular to the incoming wind direction.
[0047] like Figure 7 As shown, when the impeller rotation plane is not perpendicular to the incoming wind direction, the normally rotating blades are subjected to radial component wind force, by collecting the pitch motor current within a certain period of time, and dividing the first half cycle and the second half cycle of the pitch motor current according to the first time and the second time, by subtracting the two maximum current values of the pitch motor current in the first half cycle and the second half cycle, and taking the absolute value, and then comparing the absolute value with the current change threshold, if the absolute value of the difference between the two maximum current values is greater than the current change threshold, it can be considered that the pitch motor current has a large fluctuation.
[0048] like Figure 8 As shown, by performing Fourier transform on the pitch motor current detected within the above time range, the pitch motor current spectrum can be obtained, and then the impeller rotation frequency of the load cycle signal change is found within the specified frequency range, and the amplitude value corresponding to the impeller rotation frequency of the load cycle signal change is obtained accordingly, and by comparing the amplitude value with the amplitude threshold, if the amplitude value corresponding to the impeller rotation frequency of the load cycle signal change is greater than the amplitude threshold, it can be considered that the impeller rotation plane at this time is not perpendicular to the incoming wind direction, or it can be determined that there is a certain angle between the central axis of the impeller rotation plane and the incoming wind direction.
[0049] Through the above steps, it can be known that there is a wind deviation between the central axis of the impeller's rotation plane and the wind direction of the incoming wind. However, since the fan does not have blade position information, it is impossible to identify the deviation direction between the wind force direction of the incoming wind and the central axis of the impeller's rotation plane, that is, it is impossible to determine whether the wind direction is biased to the left or right.
[0050] See also Fig. 9 and Fig.10 When the impeller rotation plane is directly opposite to the direction of the incoming wind, the wind direction angle at this time can be limited to a standard wind direction angle, such as 180°.
[0051] like Fig.10 , a wind direction-power curve data table composed of power, wind direction angle, and wind speed, wherein in the data table, the wind direction angle is located horizontally in the data table, the power is located vertically in the data table, and 180° is used as the standard wind direction angle. A reference line facing the wind is set vertically at the standard wind direction angle. The data table is divided into two parts by the reference line facing the wind. The left side of the data table is for wind direction angles less than 180°, and the right side of the data table is for wind direction angles greater than 180°. In order to correct the wind direction angle on the left side of the data table, it is necessary to swing to the left corresponding to the phase difference angle, and in order to correct the wind direction angle on the right side of the data table, it is necessary to swing to the right corresponding to the phase difference angle. The reference line facing the wind corresponding to the standard wind direction angle is provided with a wind speed variation range.
[0052] According to the location of the wind turbine and the historical working data collected and counted, the power curve corresponding to the wind speed is obtained for different wind speeds. In addition, each power curve set along the left and right directions has a maximum power point with the largest value. The maximum power points of the power curves corresponding to different wind speeds are connected vertically in sequence to obtain the maximum power line.
[0053] When the central axis of the impeller rotation plane coincides with the incoming wind direction, the maximum power corresponding to the wind turbine appears on the reference line facing the wind in different wind speed ranges. When the impeller rotation plane is not perpendicular to the incoming wind direction, the maximum power corresponding to the wind speed will be far away from the 180° reference line facing the wind. If there is a left deviation of the convective wind, the maximum power at this time is located on the left side of the reference line facing the wind. If there is a right deviation of the convective wind, the maximum power at this time is located on the right side of the reference line facing the wind.
[0054] In actual application, the wind speed of the incoming wind at this time is detected by a sensor device or by calling the local dynamic wind speed data of the incoming wind that is open to the public, the power curve corresponding to the wind speed is selected, and the maximum power point is found along the power curve, by subtracting the wind direction angle corresponding to the maximum power point from the standard wind direction angle of 180°. If a negative value is obtained, it means that the wind direction angle corresponding to the maximum power point at this time is less than 180°, that is, the maximum power point is located on the left side of the wind reference line, the incoming wind is a left-biased wind, and the absolute value of the difference is the angle at which the yaw system needs to swing to the left. Similarly, by subtracting the wind direction angle corresponding to the maximum power point from the standard wind direction angle of 180°, if a positive value is obtained, it means that the wind direction angle corresponding to the maximum power point at this time is greater than 180°, the maximum power point is located on the right side of the wind reference line, that is, the incoming wind is a right-biased wind, and the absolute value of the difference is the angle at which the yaw system needs to swing to the right.
[0055] Preferably, in actual application, the possible wind speeds are divided into several wind speed intervals according to the wind speed values calibrated on the wind reference line. The calibrated power curve is the power curve of the maximum wind speed value in the corresponding wind speed interval. At the same time, the power curve is also the power of all wind speeds in the corresponding wind speed interval, so as to find the maximum power point of the current wind speed more quickly during the actual adjustment process.
[0056] Preferably, in actual application, the wind direction-power curve data table consisting of power, wind direction angle, and wind speed is a power curve for a specific wind speed value. When the current wind speed detected by the wind turbine is not the wind speed corresponding to the calibrated power curve, the wind direction deviation trend of the current wind turbine is used, such as Fig.10 The wind turbine shown is located in a left-biased incoming wind environment. The average value point is obtained by taking the upper and lower wind speed values corresponding to the current wind speed. At the same time, the midpoint between the maximum power points corresponding to the upper and lower wind speed values and located on the maximum power line is extracted. The line connecting the average value point and the midpoint is used as the first line, and the second line is made with the current wind speed as the starting point. The second line is parallel to the first line, and the point where the second line and the maximum power line first intersect is the maximum power point of the real-time wind speed.
[0057] The yaw system obtains the difference between the wind direction angle corresponding to the above-mentioned maximum power point and the standard wind direction angle of 180°, where a negative value is the angle corresponding to the left swing, and a positive value is the angle corresponding to the right swing. After the yaw system swings the corresponding angle, it re-detects the working current change of the variable pitch motor and uses Fourier transform to find the amplitude value corresponding to the load periodic signal change. If the amplitude value is still greater than the amplitude threshold, the corresponding maximum power point will be found according to the real-time wind speed and the power curve of the corresponding wind speed. Then, the maximum power point is subtracted from the standard wind direction angle, and the positive and negative values of the difference are used as the direction of re-adjustment, and the absolute value of the difference is used as the amplitude of the swing angle to be re-adjusted. If the amplitude value corresponding to the periodic signal is less than the amplitude threshold, the corresponding angle adjustment is stopped.
[0058] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.
Claims
1. A method for improving the wind direction accuracy of a wind turbine generator set, characterized in that: The following steps are involved: Step S1: collecting the working current driven by the pitch motor within a certain period of time, performing spectrum analysis on the current data of the pitch motor of the blade within a certain period of time, analyzing the frequency and amplitude of the blade load cycle signal, and judging whether there is a deviation between the central axis of the impeller rotation plane and the wind direction of the incoming wind; Step S2: construct a wind direction-power curve data table through power, wind direction angle, and wind speed; Step S3: calibrate the wind reference line, divide the wind speed into several wind speed intervals according to the wind speed value calibrated on the wind reference line, and calibrate the power curve of the maximum wind speed value in the wind speed interval; Step S4: dynamically detect the incoming wind speed, select the power curve corresponding to the wind speed range, and compare the maximum power point of the same power curve with the standard wind direction angle facing the wind reference line, set the adjustment direction according to the positive or negative value of the difference, set the adjustment angle according to the absolute value of the difference, and adjust the angle between the central axis of the impeller rotation plane and the incoming wind direction; Step S5: When the yaw system swings to a corresponding angle, the working current record data of the pitch motor is updated, and steps S1-S4 are re-executed. When the amplitude value corresponding to the periodic signal is less than the amplitude threshold, the corresponding angle adjustment is stopped.
2. The method for improving the wind direction accuracy of a wind turbine generator set according to claim 1, characterized in that: In the step S1, according to the variation law of the pitch motor current, the first half cycle is divided into the first time, and the second half cycle is divided into the second time, and the corresponding phase current values are compared through the pitch motor current curve of the first half cycle and the pitch motor current curve of the second half cycle; Or by superimposing and comparing the current change trajectories; or by comparing the maximum current value of the first half cycle with the maximum current value of the second half cycle.
3. The method for improving the wind direction accuracy of a wind turbine generator set according to claim 2, characterized in that: Evaluate the current changes in the first half cycle and the second half cycle by subtracting the maximum current values of the pitch motor current in the first half cycle and the second half cycle. If the absolute value of the difference obtained by subtraction is less than or equal to the current change threshold, it is considered that the pitch motor current has not fluctuated significantly; if the absolute value of the difference between the two maximum current values is greater than the current change threshold, it is considered that the pitch motor current has fluctuated significantly.
4. The method for improving the wind direction accuracy of a wind turbine generator set according to claim 1, characterized in that: In step S1, the pitch motor current is subjected to Fourier transformation to obtain a current spectrum of the pitch motor, and an amplitude value corresponding to the changed impeller rotation frequency is obtained by searching for the impeller rotation frequency at which a load cycle signal changes within a specified frequency range, and the amplitude value is compared with a preset amplitude threshold.
5. The method for improving the wind direction accuracy of a wind turbine generator set as claimed in claim 4, characterized in that: If the amplitude value corresponding to the impeller rotation frequency when the load cycle signal changes is less than or equal to the amplitude threshold, the impeller rotation plane is perpendicular to the incoming wind direction; if the amplitude value corresponding to the impeller rotation frequency when the load cycle signal changes is greater than the amplitude threshold, the impeller rotation plane is not perpendicular to the incoming wind direction.
6. The method for improving the wind direction accuracy of a wind turbine generator set according to claim 1, characterized in that: In step S2, 180° is used as the standard wind direction angle, and a wind reference line is set in the vertical direction of the standard wind direction angle, with the wind direction angle on the left being less than 180° and the wind direction angle on the right being greater than 180°.
7. The method for improving the wind direction accuracy of a wind turbine generator set according to claim 1, characterized in that: In step S3, according to the location of the wind turbine and the historical working data collected and counted, power curves corresponding to different wind speeds are obtained. Each power curve arranged along the left and right directions has a maximum power point with the largest value. The maximum power points of the power curves corresponding to different wind speeds are connected longitudinally in sequence to obtain the maximum power line.
8. The method for improving the wind direction accuracy of a wind turbine generator set according to claim 1, characterized in that: In step S4, the wind direction angle corresponding to the maximum power point of the current wind speed is subtracted from the standard wind direction angle of 180°. If a positive value is obtained, it means that the wind direction angle corresponding to the maximum power point at this time is greater than 180°, the maximum power point is located on the right side of the wind reference line, the incoming wind is a right-biased wind, and the absolute value of the difference is the angle at which the yaw system needs to swing to the right.
9. The method for improving the wind direction accuracy of a wind turbine generator set according to claim 1, characterized in that: In step S4, according to the wind direction deviation trend of the current wind turbine, the average value point is obtained with the upper and lower wind speed values corresponding to the current wind speed, and the middle point between the maximum power points corresponding to the upper and lower wind speed values and located on the maximum power line is extracted. The line connecting the average value point and the middle point is used as the first line, and the second line is made with the current wind speed as the starting point. The second line is parallel to the first line, and the point where the second line and the maximum power line first intersect is the maximum power point of the real-time wind speed.