Wind wheel imbalance detection and correction method and system based on variable pitch motor current analysis

Abstract

The invention discloses a wind wheel imbalance detection and correction method and system based on variable-pitch motor current analysis, and the method comprises the steps: comparing the current amplitudes of blade variable-pitch motors of a wind turbine generator at the same wind speed and the same azimuth angle, and obtaining a current amplitude deviation; judging whether the current amplitude deviation is greater than a preset current amplitude deviation threshold value or not; if the current amplitude deviation is greater than a preset current amplitude deviation threshold, determining that the wind wheel of the wind turbine generator is unbalanced; counting the number of times that the current amplitude deviation is greater than a preset current amplitude deviation threshold value for the unbalanced wind wheel of the wind turbine generator; and if the counted number of times is larger than or equal to the preset limit value, variable-pitch angle adjustment is conducted on the unbalanced wind wheel of the wind turbine generator according to the current amplitude deviation till the wind wheel of the wind turbine generator is balanced, and when variable-pitch angle adjustment is conducted, different pitch angles are adjusted and set according to the wind speed. And pneumatic balance and stability of the blade can be kept, vibration and fatigue damage of the wind turbine generator are reduced, and manual compensation by maintenance personnel is not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine generator sets, and in particular to a method and system for detecting and correcting wind rotor imbalance based on current analysis of a variable pitch motor. Background Art

[0002] The design, manufacturing, transportation, installation and other reasons of wind turbine blades may cause the three blades to have different aerodynamic characteristics, thus causing aerodynamic imbalance of the wind rotor, causing abnormal vibration of the wind turbine, accelerated wear and reduced operating stability of the unit.

[0003] Currently, different manufacturers mostly determine the aerodynamic imbalance of wind turbine rotors through video imaging or vibration monitoring, but this detection and determination method requires the addition of additional equipment and requires huge investment, which is not economical for manufacturers. In addition, when aerodynamic imbalance of wind turbine rotors is found, maintenance personnel are required to climb the tower to manually compensate for the blade pitch angle, but this adjustment method has a certain lag and will cause certain fatigue damage to the wind turbine. Summary of the invention

[0004] In order to solve some or all of the technical problems existing in the above-mentioned prior art, the present invention provides a method and system for detecting and correcting wind rotor imbalance based on pitch motor current analysis, which can maintain the aerodynamic balance of the blades, reduce the vibration and fatigue damage of the wind turbine set, and does not require maintenance personnel to manually compensate for the aerodynamically unbalanced blades, and has good synchronization.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for detecting and correcting wind rotor imbalance based on variable pitch motor current analysis, comprising:

[0007] Compare the current amplitudes of the wind turbine blade pitch motors at the same wind speed and azimuth to obtain the current amplitude deviation;

[0008] Determining whether the current amplitude deviation is greater than a preset current amplitude deviation threshold;

[0009] If the current amplitude deviation is greater than a preset current amplitude deviation threshold, the wind turbine rotor is unbalanced;

[0010] For an unbalanced wind turbine rotor, counting the number of times the current amplitude deviation is greater than the preset current amplitude deviation threshold;

[0011] If the counted number of times is greater than or equal to a preset limit, the pitch angle of the unbalanced wind rotor of the wind turbine is adjusted according to the current amplitude deviation until the wind rotor of the wind turbine is balanced. When adjusting the pitch angle, different pitch angle adjustment settings are made according to the wind speed.

[0012] Furthermore, in the above-mentioned wind rotor imbalance detection and correction method based on pitch motor current analysis, the preset current amplitude deviation threshold includes ±5% of the current amplitude deviation.

[0013] Furthermore, in the above-mentioned wind rotor imbalance detection and correction method based on pitch motor current analysis, the preset current amplitude deviation threshold includes ±2%-±10% of the current amplitude deviation.

[0014] Furthermore, in the above-mentioned method for detecting and correcting wind rotor imbalance based on pitch motor current analysis, the preset limit value includes any number of 5, 10, 15, 20, 25, and 30.

[0015] Furthermore, in the above-mentioned method for detecting and correcting wind rotor imbalance based on pitch motor current analysis, the preset limit value includes any number from 5 to 50.

[0016] Further, in the above-mentioned method for detecting and correcting wind rotor imbalance based on pitch motor current analysis, if the statistical number is greater than or equal to a preset limit, the pitch angle of the unbalanced wind rotor of the wind turbine is adjusted according to the current amplitude deviation until the wind rotor of the wind turbine reaches balance, which includes:

[0017] Compare and sort the current amplitudes of wind turbine blades in wind turbines;

[0018] If the current amplitude of any blade in the wind turbine rotor is smaller than the current amplitude of the other blades, the other blades are adjusted with increasing pitch angles, and the one blade is kept running in its original state; or if the current amplitude of any blade in the wind turbine rotor is larger than the current amplitude of the other blades, the one blade is adjusted with increasing pitch angles, and the other blades are kept running in their original state;

[0019] If the current amplitudes of all blades in the wind turbine rotor are greatly deviated from each other, the two blades with the largest current amplitudes are adjusted by increasing the pitch angle, and the remaining blades are kept in the original state.

[0020] The relatively large deviation includes that the difference between all blade current amplitudes is greater than or equal to 5%.

[0021] Furthermore, in the above-mentioned wind rotor imbalance detection and correction method based on pitch motor current analysis, when adjusting the pitch angle, adjusting different pitch angles according to the wind speed includes:

[0022] For blades with a wind speed less than or equal to the rated wind speed, the pitch angle is adjusted by the first single pitch angle adjustment amount;

[0023] For blades with wind speed greater than the rated wind speed, the pitch angle is adjusted by the second single pitch angle adjustment amount.

[0024] Furthermore, in the above-mentioned method for detecting and correcting wind rotor imbalance based on pitch motor current analysis, the first single pitch angle adjustment amount is smaller than the second single pitch angle adjustment amount.

[0025] In a second aspect, the present invention provides a wind rotor imbalance detection and correction system based on pitch motor current analysis, comprising:

[0026] A comparison module, wherein the comparison module is used to compare the current amplitudes of the wind turbine blade pitch motors at the same wind speed and the same azimuth angle to obtain a current amplitude deviation;

[0027] A judgment module, the judgment module is used to judge whether the current amplitude deviation is greater than a preset current amplitude deviation threshold; if the current amplitude deviation is greater than the preset current amplitude deviation threshold, the wind turbine rotor is unbalanced;

[0028] A statistical module, the statistical module is used to count the number of times the current amplitude deviation is greater than the preset current amplitude deviation threshold for the unbalanced wind turbine rotor;

[0029] A correction module, wherein the correction module is used to correct an unbalanced wind rotor of a wind turbine. If the number of times counted is greater than or equal to a preset limit, the pitch angle of the unbalanced wind rotor of the wind turbine is adjusted according to the current amplitude deviation until the wind rotor of the wind turbine is balanced. When adjusting the pitch angle, different pitch angle adjustment settings are made according to the wind speed.

[0030] The main advantages of the technical solution of the present invention are as follows:

[0031] The present invention provides a method for detecting and correcting wind rotor imbalance based on pitch motor current analysis. By comparing the current amplitudes of the pitch motors of wind turbine blades at the same wind speed and the same azimuth angle, a current amplitude deviation is obtained, and the obtained current amplitude deviation is compared with a preset current amplitude deviation threshold. This method can accurately determine whether the wind turbine rotor is balanced, and by correcting the unbalanced wind turbine rotor by adjusting the pitch angle according to the current amplitude deviation, the vibration and fatigue damage of the wind turbine rotor can be reduced. At the same time, the aerodynamic balance and aerodynamic stability of the blades can be maintained. There is no need for maintenance personnel to manually compensate for aerodynamically unbalanced blades, and the synchronization is good. In addition, the method of the present invention does not require additional equipment while solving the above-mentioned problems, and is low in cost, convenient and quick. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 This is a flow chart of a method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the structure of a wind rotor imbalance detection and correction system based on pitch motor current analysis provided in one embodiment of the present invention.

[0035] Description of reference numerals:

[0036] 10. Comparison module; 20. Judgment module; 30. Statistics module; 40. Correction module. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. 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 making creative work are within the scope of protection of the present invention.

[0038] The following is combined with Figure 1-2 , describes in detail the technical solution provided by the embodiments of the present invention.

[0039] First, as Figure 1 As shown, the present invention provides a method for detecting and correcting wind wheel imbalance based on variable pitch motor current analysis, comprising the following steps S1 to S4:

[0040] Step S1: comparing the current amplitudes of the wind turbine blade pitch motors at the same wind speed and the same azimuth to obtain the current amplitude deviation;

[0041] Step S2: determining whether the current amplitude deviation is greater than a preset current amplitude deviation threshold; if the current amplitude deviation is greater than the preset current amplitude deviation threshold, the wind turbine rotor is unbalanced;

[0042] In some optional implementations of this embodiment, the above-mentioned preset current amplitude deviation threshold includes ±5% of the current amplitude deviation.

[0043] In another optional implementation of this embodiment, the above-mentioned preset current amplitude deviation threshold can also be set as ±2%-±10% of the current amplitude deviation.

[0044] It should be noted that the specific size of the above-mentioned preset current amplitude deviation threshold is determined according to actual needs and actual applications, and the above-mentioned numerical value or numerical range is preferred. However, it should also be noted that the above-mentioned numerical range is not the only limitation of the present invention, but an exemplary description of the embodiments of the present invention.

[0045] Step S3: for the unbalanced wind turbine rotor, counting the number of times the current amplitude deviation is greater than a preset current amplitude deviation threshold;

[0046] In another optional implementation of the present invention, the above-mentioned preset limit value can also be set to any number between 5-50.

[0047] It should also be noted that the specific number of the above-mentioned preset limit values ​​is determined according to actual needs and actual applications, and the above-mentioned numerical value or numerical range is preferred. However, it should also be noted that the above-mentioned numerical range is not the only limitation of the present invention, but an exemplary description of the embodiments of the present invention.

[0048] Step S4: If the statistical number is greater than or equal to the preset limit, the pitch angle of the unbalanced wind rotor of the wind turbine is adjusted according to the current amplitude deviation until the wind rotor of the wind turbine is balanced. When adjusting the pitch angle, different pitch angles are adjusted and set according to the wind speed.

[0049] In some optional implementations of this embodiment, the above-mentioned preset limit includes any number of 5, 10, 15, 20, 25, and 30.

[0050] In the wind rotor imbalance detection and correction method based on pitch motor current analysis of the present invention, if the statistical number of times is greater than or equal to the preset limit, the pitch angle of the unbalanced wind rotor of the wind turbine is adjusted according to the current amplitude deviation until the wind rotor of the wind turbine reaches balance, which includes:

[0051] Compare and sort the current amplitudes of the wind turbine blades in the wind turbine set; if the current amplitude of any blade in the wind turbine set is smaller than the current amplitudes of the other blades, increase the pitch angle adjustment for the other blades, and keep one blade running in the original state; or if the current amplitude of any blade in the wind turbine set is larger than the current amplitudes of the other blades, increase the pitch angle adjustment for one blade, and keep the other blades running in the original state; if there is a large deviation between the current amplitudes of all blades in the wind turbine set, increase the pitch angle adjustment for the two blades with the largest current amplitude ranking, and keep the other blades running in the original state;

[0052] The relatively large deviation includes that the difference between the amplitudes of all blade currents is greater than or equal to 5%.

[0053] In another optional implementation of this embodiment, the aforementioned relatively large deviation includes that the difference between all blade current amplitudes is greater than or equal to any value between 1-20.

[0054] Specifically, in the present invention, when adjusting the pitch angle, different pitch angle adjustment settings according to the wind speed include:

[0055] For blades with wind speed less than or equal to the rated wind speed, the pitch angle is adjusted by the first single pitch angle adjustment amount; for blades with wind speed greater than the rated wind speed, the pitch angle is adjusted by the second single pitch angle adjustment amount. The first single pitch angle adjustment amount is less than the second single pitch angle adjustment amount.

[0056] The technical solution of the present invention is further described in detail below in combination with the practical application of a wind turbine with three blades:

[0057] First, it is necessary to obtain the current timing of the three blade pitch motors, the wind rotor azimuth timing, and the wind speed timing, and perform statistical analysis on the timing.

[0058] Compare the current amplitudes of the three blade pitch motors at the same wind speed and azimuth:

[0059] If the current amplitude deviation of the pitch motor between the three blades is less than 5%, it means that the wind rotor is balanced and can continue to operate in the original state; if the current amplitude deviation of the pitch motor between the three blades is greater than or equal to 5%, it means that the wind rotor is unbalanced, and the number of times the current amplitude deviation is greater than or equal to 5% is counted. When the cumulative number reaches a certain limit, the blades are adjusted according to the current amplitude deviation. During the adjustment process, there are two situations according to the actual application:

[0060] The first case: the current amplitude deviation of one blade is large, and the current amplitudes of the other two blades are close;

[0061] If the current amplitude of one blade is less than the current amplitude of the other two blades, the pitch angle adjustment is increased for the other two blades, and one blade is kept running in the original state; or if the current amplitude of one blade is greater than the current amplitude of the other two blades, the pitch angle adjustment is increased for one blade, and the other two blades are kept running in the original state;

[0062] The second case: the current amplitudes of the three blades are greatly deviated from each other;

[0063] The current amplitudes are sorted, and the pitch angle adjustment is increased for the two larger blades, while the blade with the smaller current amplitude keeps running in the original state.

[0064] Specifically, in the embodiment of the present invention, when the blade pitch angle is adjusted, different pitch angle adjustment settings are performed according to the wind speed:

[0065] When the wind speed is ≤ the rated wind speed, the pitch angle is adjusted according to the single pitch angle adjustment amount β1, and the current deviation of the three blade pitch motors is observed at the same time, until the current deviation of the three blade pitch motors is less than 5%. When the wind speed is greater than the rated wind speed, the pitch angle is adjusted according to the single pitch angle adjustment amount β2, and the current deviation of the three blade pitch motors is observed at the same time, until the current deviation of the three blade pitch motors is less than 5%.

[0066] Specifically, the single pitch angle adjustment amount β1 is smaller than β2.

[0067] Specifically, the pitch angle adjustment range of a wind turbine is usually between 0° and +90°. At low wind speeds, the pitch angle is close to 0° to capture the maximum amount of wind energy; at high wind speeds, the pitch angle will increase to prevent overload and damage. The above-mentioned single pitch angle adjustment amounts β1 and β2 are adjusted according to actual needs, and the adjustment range is between 0° and +90°. For example, a single adjustment is performed at intervals of 0.2°, 0.5°, or any angle range of 0.1° to 5°. Repeat the above-mentioned single adjustments of the same or different angles multiple times until the current deviation of the three-blade pitch motor is less than 5% and stop.

[0068] It should be noted that when the wind turbine is in normal power generation (non-fault condition), if the wind speed is ≤ the rated wind speed, the pitch control will not work (usually it is tracking the optimal Cp or torque control at this time). If the pitch adjustment is required due to the imbalance of the wind rotor, a small adjustment will be made at this time. A slightly larger single adjustment will cause a larger power fluctuation, thus affecting the power generation of the unit. If the wind speed is greater than the rated wind speed, the pitch control has already taken effect. Generally speaking, the three blades already have a certain pitch angle. If the pitch adjustment is required due to the imbalance of the wind rotor, the adjustment range can be larger, and a slightly larger single adjustment will not cause too much fluctuation.

[0069] In summary, the wind rotor imbalance detection and correction method based on pitch motor current analysis of the present invention can automatically adjust the wind rotor imbalance according to the wind turbine operation data, and reduce the vibration and fatigue damage of the wind turbine. At the same time, the method of the present invention does not need to add additional equipment in the process of solving the above technical problems, and is low-cost, convenient and fast.

[0070] Second, as Figure 2 As shown, the present invention provides a wind rotor imbalance detection and correction system based on pitch motor current analysis, comprising: a comparison module 10, a judgment module 20, a statistical module 30 and a correction module 40, wherein:

[0071] The comparison module 10 is used to compare the current amplitudes of the wind turbine blade pitch motors at the same wind speed and the same azimuth to obtain the current amplitude deviation; the judgment module 20 is used to judge whether the current amplitude deviation is greater than a preset current amplitude deviation threshold; if the current amplitude deviation is greater than the preset current amplitude deviation threshold, the wind turbine rotor is unbalanced; the statistical module 30 is used to count the number of times the current amplitude deviation is greater than the preset current amplitude deviation threshold for the unbalanced wind turbine rotor; the correction module 40 is used to correct the unbalanced wind turbine rotor, and if the statistical number is greater than or equal to the preset limit, the pitch angle of the unbalanced wind turbine rotor is adjusted according to the current amplitude deviation until the wind turbine rotor is balanced, wherein, when adjusting the pitch angle, different pitch angle adjustments are made according to the wind speed.

[0072] Therefore, the wind rotor imbalance detection and correction system based on pitch motor current analysis of the present invention can automatically adjust the wind rotor imbalance according to the wind turbine operation data, thereby reducing the vibration and fatigue damage of the wind turbine. At the same time, the method of the present invention does not need to add additional equipment in the process of solving the above technical problems, and is low-cost, convenient and fast.

[0073] In summary, the present invention performs statistical analysis on the current timing of the three-blade pitch motors, the wind rotor azimuth timing, and the wind speed timing, and obtains the blades with larger current deviation of the pitch motor under the same wind speed and the same azimuth, and performs pitch angle compensation according to the direction of the current deviation. This can solve the problem of wind rotor imbalance in real time and conveniently, reduce the vibration and fatigue damage of the wind turbine, and ensure the normal operation of the wind turbine.

[0074] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, "front", "back", "left", "right", "upper" and "lower" in this article are all referenced to the placement state shown in the accompanying drawings.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting and correcting wind rotor imbalance based on pitch motor current analysis, characterized in that: include: Compare the current amplitudes of the wind turbine blade pitch motors at the same wind speed and azimuth to obtain the current amplitude deviation; Determining whether the current amplitude deviation is greater than a preset current amplitude deviation threshold; If the current amplitude deviation is greater than a preset current amplitude deviation threshold, the wind turbine rotor is unbalanced; For an unbalanced wind turbine rotor, counting the number of times the current amplitude deviation is greater than the preset current amplitude deviation threshold; If the counted number of times is greater than or equal to a preset limit, the pitch angle of the unbalanced wind rotor of the wind turbine is adjusted according to the current amplitude deviation until the wind rotor of the wind turbine is balanced. When adjusting the pitch angle, different pitch angle adjustment settings are made according to the wind speed.

2. The method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to claim 1 is characterized in that: The preset current amplitude deviation threshold includes ±5% of the current amplitude deviation.

3. The method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to claim 1 is characterized in that: The preset current amplitude deviation threshold includes ±2%-±10% of the current amplitude deviation.

4. The method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to claim 1, characterized in that: The preset limit value includes any number of 5, 10, 15, 20, 25, and 30.

5. The method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to claim 1, characterized in that: The preset limit value includes any number between 5-50.

6. The method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to claim 1, characterized in that: If the counted number of times is greater than or equal to a preset limit, adjusting the pitch angle of the unbalanced wind rotor of the wind turbine generator set according to the current amplitude deviation until the wind rotor of the wind turbine generator set reaches a balance includes: Compare and sort the current amplitudes of wind turbine blades in wind turbines; If the current amplitude of any blade in the wind turbine rotor is smaller than the current amplitude of the other blades, the other blades are adjusted with increasing pitch angles, and the one blade is kept running in its original state; or if the current amplitude of any blade in the wind turbine rotor is larger than the current amplitude of the other blades, the one blade is adjusted with increasing pitch angles, and the other blades are kept running in their original state; If the current amplitudes of all blades in the wind turbine rotor are greatly deviated from each other, the two blades with the largest current amplitudes are adjusted by increasing the pitch angle, and the remaining blades are kept in the original state. The relatively large deviation includes that the difference between all blade current amplitudes is greater than or equal to 5%.

7. The method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to claim 1, characterized in that: When adjusting the pitch angle, different pitch angle adjustment settings are made according to the wind speed, including: For blades with a wind speed less than or equal to the rated wind speed, the pitch angle is adjusted by the first single pitch angle adjustment amount; For blades with wind speed greater than the rated wind speed, the pitch angle is adjusted by the second single pitch angle adjustment amount.

8. The method for detecting and correcting wind rotor imbalance based on pitch motor current analysis according to claim 7 is characterized in that: The first single pitch angle adjustment amount is smaller than the second single pitch angle adjustment amount.

9. A wind rotor imbalance detection and correction system based on pitch motor current analysis, characterized in that: include: A comparison module, wherein the comparison module is used to compare the current amplitudes of the wind turbine blade pitch motors at the same wind speed and the same azimuth angle to obtain a current amplitude deviation; A judging module, the judging module is used to judge whether the current amplitude deviation is greater than a preset current amplitude deviation threshold; If the current amplitude deviation is greater than a preset current amplitude deviation threshold, the wind turbine rotor is unbalanced; A statistical module, the statistical module is used to count the number of times the current amplitude deviation is greater than the preset current amplitude deviation threshold for the unbalanced wind turbine rotor; A correction module, wherein the correction module is used to correct an unbalanced wind rotor of a wind turbine. If the number of times counted is greater than or equal to a preset limit, the pitch angle of the unbalanced wind rotor of the wind turbine is adjusted according to the current amplitude deviation until the wind rotor of the wind turbine is balanced. When adjusting the pitch angle, different pitch angle adjustment settings are made according to the wind speed.

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