Wind turbine flutter suppression method, device, control system and wind turbine

Abstract

The present application relates to the technical field of wind turbines, and provides a method, device, control system and wind turbine for suppressing flutter of wind turbines, the method comprising: determining the cabin wind direction angle between the wind direction and the cabin orientation; determining a pitching method for changing the pitch angle according to the cabin wind direction angle; wherein the pitching method comprises a speed control pitching scheme and a pitching sequence pitching scheme; the speed control pitching scheme comprises: adjusting the pitch angle of the wind turbine blades according to the speed of the wind turbine rotor, so that the wind turbine rotor speed is maintained within a preset speed range until the flutter of the wind turbine is suppressed; the pitching sequence pitching scheme comprises: performing a pitching operation on the pitch angle of the wind turbine blades according to a preset pitching rule until the flutter of the wind turbine is suppressed. The present application can suppress the flutter of the wind turbine by using the method without using yaw when the wind turbine loses power with the help of a lower power backup power supply.

Description

Technical Field

[0001] The present application relates to the technical field of wind turbines, and in particular to a method, device, control system and wind turbine flutter suppression method for a wind turbine. Background Art

[0002] For large wind turbines, as the diameter of the impeller and the height of the tower increase, the possibility of the wind turbine blades fluttering in a static state gradually increases. In the prior art, the flutter suppression of wind turbines is usually achieved by changing the wind direction angle of the nacelle (i.e., yaw) in combination with changing the pitch angle. Under normal circumstances, the controller of the wind turbine can change the orientation of the nacelle by driving the yaw motor installed in the nacelle to change the wind direction angle of the nacelle, and then change the installation angle of the blade relative to the hub by the action of the variable pitch motor in the hub to change the pitch angle. It is well known that the yaw motor consumes a lot of energy, while the variable pitch motor consumes less power. However, when the power grid is out of power, the wind turbine can sometimes only be equipped with a small diesel generator for power supply, and the output power is not enough to support the joint action of yaw and variable pitch. Therefore, the flutter of the wind turbine cannot be effectively suppressed. Summary of the invention

[0003] In view of this, embodiments of the present application provide a method, device, control system and wind turbine for suppressing flutter of a wind turbine, which can suppress flutter of the wind turbine without using yaw.

[0004] In a first aspect, an embodiment of the present application provides a method for suppressing flutter of a wind turbine, comprising:

[0005] Determine the wind direction angle between the nacelle orientation of the wind turbine and the wind direction;

[0006] Determine a pitch change strategy for changing the pitch angle according to the cabin wind direction angle; wherein the pitch change strategy includes a speed control pitch change scheme and a pitch change sequence pitch change scheme;

[0007] The speed control pitch change scheme includes: adjusting the pitch angle of the wind turbine blades according to the speed of the wind turbine rotor, so that the wind turbine rotor speed is maintained within a preset speed range until the flutter of the wind turbine is suppressed;

[0008] The pitch sequence pitch scheme includes: performing pitch operation on the wind turbine blades according to a pitch angle sequence in a preset pitch rule until the flutter of the wind turbine is suppressed.

[0009] In some embodiments, the pitch change strategy for determining the pitch angle according to the nacelle wind direction angle includes:

[0010] When the angle of the cabin wind direction angle is less than the first angle or the angle of the cabin wind direction angle is greater than or equal to the second angle, the speed control pitch change scheme is used to change the pitch angle;

[0011] When the angle of the wind direction of the nacelle is greater than or equal to the first angle and less than the second angle, a pitch angle is changed by using a pitch sequence pitch change scheme;

[0012] The value range of the first angle is greater than or equal to 40 degrees and less than or equal to 70 degrees; the value range of the second angle is greater than or equal to 110 degrees and less than or equal to 140 degrees.

[0013] In some embodiments, adjusting the pitch angle of the wind turbine blades according to the wind turbine rotor speed so that the wind turbine rotor speed remains within a preset speed range includes:

[0014] Wherein, after each adjustment of the pitch angles of the three blades of the wind turbine, a first preset detection time is interval to detect whether the rotation speed of the wind rotor is within the preset rotation speed range;

[0015] Wherein, the preset speed range refers to between the first speed and the second speed;

[0016] If it is detected that the rotation speed of the wind rotor is less than the first rotation speed, the pitch angles of the three blades of the wind turbine are respectively reduced by preset adjustment angles;

[0017] If it is detected that the rotation speed of the wind rotor is greater than the second rotation speed, the pitch angles of the three blades of the wind turbine generator are increased by preset adjustment angles respectively;

[0018] The relationship between the first speed and the second speed satisfies 0<first speed<second speed<12 rpm.

[0019] In some embodiments, performing pitch operation on the wind turbine blades according to the pitch angle sequence in the preset pitch change rule includes:

[0020] Controlling the three blades of the wind turbine to change the pitch angle to a first sequence value of the pitch angle sequence;

[0021] Detecting whether the flutter of the wind turbine generator is suppressed at an interval of a second preset detection time;

[0022] If it is not suppressed, the three blades of the wind turbine are subjected to pitch changing operation according to a preset pitch changing rule, so that the pitch angle reaches the second sequence value of the pitch angle sequence;

[0023] After the pitch operation, detecting again at an interval of the second preset detection time whether the flutter of the wind turbine generator is suppressed;

[0024] If it is not suppressed, continue to perform pitch changing operation on the three blades of the wind turbine according to the preset pitch changing rule, so that the pitch angle reaches the next sequence value in the pitch angle sequence;

[0025] The preset pitch change rules include:

[0026] The pitch angles of the three blades in the pitch angle sequence are increased or decreased in sequence respectively;

[0027] The difference between the maximum and minimum pitch angles of the same blade in the pitch angle sequence is greater than the maximum value of the pitch angle interval span that generates flutter accumulation;

[0028] The absolute value of the difference between adjacent sequence values ​​of the pitch angle of the same blade in the pitch angle sequence is smaller than the minimum value of the distance between the pitch angle intervals generating flutter accumulation.

[0029] In some embodiments, the maximum span of the pitch angle interval generating flutter accumulation is greater than 60 degrees; and the minimum distance between the pitch angle intervals generating flutter accumulation is less than 35 degrees.

[0030] In some embodiments, the determination of whether the flutter of the wind turbine is suppressed includes:

[0031] Collect vibration signals from a tower vibration sensor or a blade vibration sensor located on the wind turbine;

[0032] Performing spectrum analysis on the vibration signal, and extracting the amplitude-frequency component of the vibration signal in the range of 0.2 Hz to 3.0 Hz as the equivalent amplitude;

[0033] If the equivalent amplitude does not exceed the preset value, it is determined that the flutter of the wind turbine is suppressed, wherein the preset value has a value range of 0.004 m / s^2<preset value<0.1 m / s^2.

[0034] In some embodiments, after the flutter of the wind turbine generator is suppressed, the method further includes:

[0035] Controlling the three blades of the wind turbine to return to a feathering position;

[0036] The feathering position refers to a position where the pitch angle is greater than or equal to 80 degrees and less than or equal to 95 degrees.

[0037] In a second aspect, an embodiment of the present application provides a wind turbine flutter suppression device, comprising:

[0038] A calculation module, used to determine a cabin wind direction angle between a cabin orientation of a wind turbine and a wind direction;

[0039] A determination module, used to determine a variable pitch strategy for changing the pitch angle according to the nacelle wind direction angle;

[0040] Wherein, the pitch change strategy includes a speed control pitch change scheme and a pitch change sequence pitch change scheme;

[0041] The speed control pitch change scheme includes: adjusting the pitch angle of the wind turbine blades according to the speed of the wind turbine rotor, so that the wind turbine rotor speed is maintained within a preset speed range until the flutter of the wind turbine is suppressed;

[0042] The pitch sequence pitch scheme includes: performing pitch operation on the wind turbine blades according to a pitch angle sequence in a preset pitch rule until the flutter of the wind turbine is suppressed.

[0043] In a third aspect, an embodiment of the present application provides a control system for a wind turbine, including a controller and a pitch drive system;

[0044] The variable pitch drive system is used to receive instructions from the controller and change the pitch of the blades of the wind turbine;

[0045] The controller is used to execute the above-mentioned wind turbine flutter suppression method and output control instructions to the variable pitch drive system.

[0046] In a fourth aspect, an embodiment of the present application provides a wind turbine, including the control system of the above-mentioned wind turbine.

[0047] The embodiments of the present application have the following beneficial effects: the present application first determines the angle between the wind direction and the cabin wind direction of the cabin; and then determines whether to use a speed-controlled pitch change scheme or a pitch sequence pitch change scheme for the pitch change operation according to the cabin wind direction angle. Through this method, the present application can achieve wind turbine flutter suppression without using yaw when the wind turbine loses power and with the help of a lower-power backup power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 A schematic diagram of the structure of a wind turbine generator according to an embodiment of the present application is shown;

[0050] Figure 2 A schematic diagram of the wind direction angle of the cabin in an embodiment of the present application is shown;

[0051] Figure 3 A schematic diagram of the pitch angle of an embodiment of the present application is shown;

[0052] Figure 4 A first schematic diagram of a wind turbine flutter suppression method according to an embodiment of the present application is shown;

[0053] Figure 5 A schematic diagram of a vibration accumulation interval generated in an embodiment of the present application is shown;

[0054] Figure 6 A second flow chart of the method for suppressing flutter of a wind turbine according to an embodiment of the present application is shown;

[0055] Figure 7 A structural schematic diagram of a wind turbine flutter suppression device according to an embodiment of the present application is shown.

[0056] Component Symbols:

[0057] 1-blade; 2-nacelle; 3-tower; 4-hub; 10-calculation module; 20-determination module;

[0058] a-blade azimuth; b-nacelle wind direction angle; c-pitch angle; d-flutter accumulation interval; e-interval span; f-interval distance. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0060] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0061] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0062] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0063] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0064] For large wind turbines, as the diameter of the impeller and the height of the tower increase, the possibility of vibration of the wind turbine blades in a static state gradually increases.

[0065] like Figure 1-Figure 3 As shown, a wind turbine generally includes but is not limited to a tower, a nacelle, a hub and blades, wherein the hub 4 and the blades 1 are combined together to form a wind wheel. The nacelle 2 is mounted on the tower 3, the hub 4 is mounted at the front end of the nacelle 2, and the three blades 1 are symmetrically mounted along the side wall of the hub 4. The angle between the central axis of the nacelle 2 and the wind direction is referred to as the nacelle wind direction angle. The installation angle of the blades 1 relative to the hub 4 is dynamically adjustable. This angle is called the pitch angle. The pitch angle is Figure 3 As shown in Figure c. Under the action of wind, the wind wheel rotates around the central axis of the nacelle 2. The angle between the blade 1 and the tower 3 is called the blade azimuth angle. Figure 1 As shown in a.

[0066] In the prior art, wind turbine flutter suppression is usually achieved by changing the wind direction angle of the nacelle (i.e., yaw) in combination with changing the pitch angle. Usually, the controller of the wind turbine can change the orientation of the nacelle 2 by driving the yaw motor installed in the nacelle 2 to change the wind direction angle of the nacelle, and change the installation angle of the blade relative to the hub 4 by the action of the variable pitch motor in the hub 4 to change the pitch angle. It is well known that the yaw motor consumes a large amount of energy, while the variable pitch motor consumes less energy. However, when the power grid is out of power, the wind turbine can sometimes only be equipped with a small diesel generator for power supply, and the output power is insufficient to support the joint action of yaw and variable pitch. Therefore, the flutter of the wind turbine cannot be effectively suppressed.

[0067] The present application proposes a method for achieving wind turbine flutter suppression without relying on yaw and only changing the pitch angle according to pitch change.

[0068] The wind turbine generator flutter suppression method is described below in conjunction with some specific embodiments.

[0069] Figure 4 A schematic flow chart of a method for suppressing wind turbine flutter according to an embodiment of the present application is shown. Exemplarily, the method for suppressing wind turbine flutter includes the following steps:

[0070] Step S100, determining the wind direction angle between the orientation of the wind turbine nacelle and the wind direction.

[0071] Among them, Figure 2 As shown, the cabin wind direction angle b is specifically the angle between the cabin centerline and the wind direction. When determining the cabin wind direction angle, it can be measured by a wind vane installed on the top of the cabin or a wind tower several kilometers in front of the wind turbine. The wind vane or wind tower can sense the angle between the incident airflow and the centerline of the sensor, and then convert it into an electrical signal and send it to the wind turbine controller to determine the cabin wind direction angle.

[0072] Step S200, determining a variable pitch strategy for changing the pitch angle according to the nacelle wind direction angle.

[0073] Among them, the pitch change strategy includes a speed control pitch change scheme and a pitch change sequence pitch change scheme.

[0074] The speed control pitch change scheme includes: adjusting the pitch angle of the wind turbine blades according to the speed of the wind turbine rotor to keep the wind turbine rotor speed within a preset speed range until the flutter of the wind turbine is suppressed.

[0075] The pitch sequence pitch scheme includes: performing pitch operation on the wind turbine blades according to a pitch angle sequence in a preset pitch rule until the flutter of the wind turbine is suppressed.

[0076] Generally, for wind turbines, the nacelle wind direction angle and the pitch angle are important factors affecting wind energy capture. The nacelle wind direction angle is in the range of [0, 180]. When the nacelle wind direction angle is close to 90 degrees, the wind turbine cannot capture wind energy no matter what angle is used. When the nacelle wind direction angle is close to 0 degrees or 180 degrees, wind energy can be captured by adjusting the appropriate pitch angle to rotate the wind rotor. The smaller the pitch angle, the greater the captured wind energy and the higher the stable speed of the wind rotor. Conversely, the larger the pitch angle, the smaller the captured wind energy. The blade azimuth angle changes continuously when the wind rotor rotates, and there is no condition for blade flutter accumulation. Therefore, when the nacelle wind direction angle is close to 0 degrees or 180 degrees, the wind rotor can be rotated to suppress blade flutter, that is, the speed control pitch scheme can be used to suppress flutter. Furthermore, when the wind direction angle of the nacelle is close to 90 degrees, relying on the pitch action is not enough to rotate the wind rotor. At this time, the flutter can be suppressed by a specific pitch sequence method, that is, the pitch sequence pitch scheme is used to suppress the flutter.

[0077] Further, according to the above-mentioned influence of the nacelle wind direction angle and the pitch angle on capturing wind energy, the pitch changing method for determining the change of the pitch angle according to the nacelle wind direction angle described in the present application includes:

[0078] When the angle of the cabin wind direction is less than the first angle or the angle of the cabin wind direction is greater than or equal to the second angle, the speed-controlled variable pitch scheme is used to change the pitch angle.

[0079] When the angle of the wind direction of the nacelle is greater than or equal to the first angle and less than the second angle, a pitch sequence pitch change scheme is adopted to change the pitch angle.

[0080] The value range of the first angle is greater than or equal to 40 degrees and less than or equal to 70 degrees; the value range of the second angle is greater than or equal to 110 degrees and less than or equal to 140 degrees.

[0081] Specifically, in the present application, when the nacelle wind direction angle is greater than 0 degrees and less than the first angle, the wind turbine is said to be facing the wind; when the nacelle wind direction angle is greater than or equal to the second angle, the wind turbine is said to be facing away from the wind; and when the nacelle wind direction angle is greater than or equal to the first angle and less than the second angle, the wind turbine is said to be facing sideways to the wind. The first angle and the second angle are selected to ensure that the wind rotor can effectively rotate when the wind turbine is facing the wind and when the wind turbine is facing away from the wind, and the wind rotor can hardly rotate when the wind turbine is facing sideways to the wind. In the present application, by using wind turbine load simulation software (such as Bladed) for calculation, the first angle takes a value between [40,70] and the second angle takes a value between [110,140], which can simultaneously meet the speed requirements of the above three different wind turbines in the wind-facing state.

[0082] It is understandable that in the present application, when the wind turbine is facing the wind or facing away from the wind, a speed-controlled pitch-changing scheme is used to change the pitch angle, and when the wind turbine is facing the wind sideways, a pitch-changing sequence pitch-changing scheme is used to change the pitch angle.

[0083] In some embodiments, adjusting the pitch angle of the wind turbine blades according to the wind turbine rotor speed so that the wind turbine rotor speed remains within a preset speed range includes:

[0084] After each adjustment of the pitch angles of the three blades of the wind turbine, a first preset detection time is interval to detect whether the wind wheel rotation speed is within the preset rotation speed range; the preset rotation speed range is between the first rotation speed and the second rotation speed.

[0085] If it is detected that the rotation speed of the wind wheel is less than the first rotation speed, the pitch angles of the three blades of the wind turbine are respectively reduced by preset adjustment angles.

[0086] If it is detected that the rotation speed of the wind wheel is greater than the second rotation speed, the pitch angles of the three blades of the wind turbine generator are respectively increased by a preset adjustment angle.

[0087] Among them, since the conditions for flutter accumulation can be destroyed as long as the wind rotor rotates, the first speed in this application only needs to be greater than 0. In order to avoid the wind turbine being unsafe due to the excessive speed of the wind rotor, the setting of the second speed needs to ensure the safety of the wind turbine. Therefore, the value relationship between the first speed and the second speed in this application needs to satisfy 0<first speed<second speed<12rpm. In addition, the preset adjustment angle needs to be selected according to the control response of the wind turbine. When the first preset detection time is 10 seconds, the value range of the preset adjustment angle is greater than or equal to 1 degree and less than or equal to 8 degrees.

[0088] Specifically, when the wind turbine is facing the wind or facing away from the wind, the rotor speed is controlled by pitch control to be maintained between the first speed and the second speed. When detecting the rotor speed, the present application can directly detect the rotor speed by installing a circumferential bolt and a proximity switch on the main shaft bearing surface of the wind turbine nacelle, or install a high-speed encoder on the wind turbine to determine the generator speed, and divide the generator speed by the gearbox speed ratio to indirectly measure the rotor speed. When the speed control pitch scheme is just activated, the wind turbine is in a shutdown state. At this time, the rotor speed is 0, which is less than the first speed, and the pitch angles of the three blades of the wind turbine are controlled to be reduced by the preset adjustment angles on the original basis. After the first preset detection time, the rotor speed is detected again. If it is detected that the rotor speed is still less than the first speed, the pitch angles of the three blades of the wind turbine are controlled to be reduced by the preset adjustment angles on the basis of the last time. If it is detected that the rotor speed is greater than the second speed, the pitch angles of the three blades of the wind turbine are controlled to be increased by the preset adjustment angles on the basis of the last time. As long as the flutter of the wind turbine generator cannot be suppressed, the above steps will be repeated, that is, the rotor speed is detected at intervals of the first preset detection time, and then the pitch angles of the three blades are controlled to increase or decrease a preset adjustment angle according to the rotor speed. This can avoid the continuous acceleration or deceleration of the wind rotor, so that the wind rotor fluctuates within a suitable speed range. Due to the continuous change of the blade azimuth angle, the condition for the accumulation of blade flutter is lost, and the blade flutter disappears under the action of its own damping. During the speed control process, when it is detected that the flutter of the wind turbine generator is suppressed, the speed control pitch change scheme is stopped, and then the pitch angles of the three blades are controlled to return to the feathering position, even if the pitch angle stays between 80 degrees and 95 degrees. Among them, the first preset detection time is usually between 5 seconds and 30 seconds.

[0089] In some embodiments, the pitching operation of the wind turbine blades according to the pitch angle sequence in the preset pitching rule includes: controlling the three blades of the wind turbine to pitch to the first sequence value of the pitch angle sequence; detecting whether the flutter of the wind turbine is suppressed at a second preset detection time interval; if not suppressed, the three blades of the wind turbine are pitched according to the preset pitching rule, so that the pitch angle is pitched to the second sequence value of the pitch angle sequence; after the pitching operation, the second preset detection time interval is again detected to see whether the flutter of the wind turbine is suppressed; if not suppressed, the three blades of the wind turbine are pitched according to the preset pitching rule, so that the pitch angle is pitched to the next sequence value of the pitch angle sequence. The above pitching operation and the action of detecting whether the flutter of the wind turbine is suppressed are continuously repeated until the last sequence value in the pitch angle sequence is reached. Then, according to whether the flutter is suppressed, the three blades of the wind turbine are pitched according to the preset pitching rules, so that the pitch angle returns to the feathering position or reaches the first sequence value of the pitch angle sequence, and the above operation is repeated.

[0090] Among them, the preset pitch change rules include: the pitch angles of the three blades in the pitch angle sequence increase or decrease in sequence respectively; the difference between the maximum and minimum values ​​of the pitch angle of the same blade in the pitch angle sequence is greater than the maximum value of the span of the pitch angle interval that produces flutter accumulation; the absolute value of the difference between adjacent sequence values ​​of the pitch angle of the same blade in the pitch angle sequence is less than the minimum value of the distance between the pitch angle intervals that produce flutter accumulation.

[0091] Specifically, Figure 5 As shown, the description of the span of the pitch angle interval generating flutter accumulation and the distance between adjacent pitch angle intervals generating flutter accumulation is as follows:

[0092] The present application uses a computing software with a fluid-solid coupling simulation function to conduct a simulation study, examining the blade flutter accumulation of a single blade at different cabin wind direction angles, blade azimuth angles, and pitch angles. The results show that under the influence of any cabin wind direction angle and blade azimuth angle, there is a part of the pitch angle interval that will produce flutter accumulation, and the other intervals are non-risk intervals (i.e., intervals that do not produce flutter accumulation). In the prior art, some methods will determine an optimal pitch angle to reduce flutter accumulation, but this method requires knowing the blade azimuth angle, which is relatively complicated. In the present application, there is no need to determine the optimal pitch angle, only to keep the pitch angle outside the pitch interval that produces flutter accumulation, that is, only to keep the pitch angle in the non-risk interval. Figure 5As shown, in all working intervals of the pitch angle, there may be more than one continuous interval that "generates flutter accumulation". According to analysis, the span of the pitch angle interval that generates flutter accumulation and the distance between adjacent pitch angle intervals that generate flutter accumulation can be obtained according to all pitch angle intervals that generate flutter accumulation. Figure 5 The interval span e of the middle gray area is the pitch angle interval span that produces flutter accumulation, the distance f between two pitch angle intervals d that produce flutter accumulation is the distance between adjacent pitch angle intervals that produce flutter accumulation, and -10 degrees to 100 degrees is the entire working range of the pitch angle.

[0093] Furthermore, when the difference between the maximum and minimum values ​​in the pitch angle sequence exceeds the maximum value of the pitch angle interval generating flutter accumulation, and the step length of each change in the sequence is less than the minimum value of the distance between the intervals generating flutter accumulation, there must be at least one pitch angle in the pitch angle sequence in the non-risk interval, so that the wind turbine does not have blade flutter accumulation. It should be noted that since the wind rotor does not rotate, the risk situation of each pitch angle will not change during the adjustment of the pitch angle, so the above solution is feasible.

[0094] Specifically, Figure 6 As shown, the specific implementation process of performing pitch operation on the wind turbine blades according to the pitch angle sequence in the preset pitch change rule is as follows:

[0095] Step S10, controlling the three blades of the wind turbine to change pitch to the initial value of the pitch angle sequence (p11, p12, p13), and then executing step S20, detecting whether the flutter of the wind turbine is suppressed at an interval of a second preset detection time; if the flutter of the wind turbine is suppressed, executing step S30, controlling the three blades of the wind turbine to return to the feather position; if the flutter of the wind turbine is not suppressed, executing step S40, performing pitch operation on the three blades of the wind turbine according to the preset pitch rule, and the pitch angle after pitch change is (pi1, pi2, pi3); then looping through steps S20 and S40 until executing to step S30 or step S50. If step S50 is executed, the pitch angle is changed to (pn1, pn2, pn3), and then step S60 is continued to be executed, and whether the flutter of the wind turbine is suppressed is detected at an interval of a second preset detection time. If it is suppressed, step S30 is executed to control the three blades of the wind turbine to return to the propeller position. If the flutter of the wind turbine is not suppressed, return to step S10.

[0096] The maximum value of the span of the pitch angle interval generating flutter accumulation is defined as px; and the minimum value of the distance between adjacent pitch angle intervals generating flutter accumulation is defined as py.

[0097] According to Figure 6The specific implementation process shown in the figure can effectively suppress the flutter of the wind turbine generator if the pitch angle sequence {pil.pi2.pi3 (i=1.2…n)} can simultaneously meet the following preset pitch change rules:

[0098] Rule 1:

[0099] p11>p21>p31>…>pn1 or p11 <p21<p31<…<pn1

[0100] p12>p22>p32>…>pn2 or p12 <p22<p32<…<pn2

[0101] p13>p23>p33>…>pn3 or p13 <p23<p33<…<pn3

[0102] Rule 2:

[0103] Max{p11,p21,…,pn1}-Min{p11,p21,…,pn1}>px

[0104] Max{p12,p22,…,pn2}-Min{p12,p22,…,pn2}>px

[0105] Max{p13,p23,…,pn3}-Min{p13,p23,…,pn3}>px

[0106] Rule 3:

[0107] Max{abs(p11-p21),abs(p21-p31),…abs(p(n-1)1-pn1)} <py

[0108] Max{abs(p12-p22),abs(p22-p32),…abs(p(n-1)2-pn2)} <py

[0109] Max{abs(p13-p23),abs(p23-p33),…abs(p(n-1)3-pn3)} <py。

[0110] The maximum value px of the span of the pitch angle interval generating flutter accumulation is usually greater than 60 degrees; the minimum value py of the distance between the pitch angle intervals generating flutter accumulation is usually less than 35 degrees.

[0111] Furthermore, the method for detecting whether the flutter of the wind turbine generator is suppressed in the present application is: by collecting the vibration signal of the tower vibration sensor or the blade vibration sensor, judging whether the amplitude of the signal spectrum in the range of 0.2Hz to 3.0Hz exceeds the preset value according to the vibration signal; if the amplitude does not exceed the preset value, the flutter of the wind turbine generator is suppressed, and if the amplitude exceeds the preset value, the flutter of the wind turbine generator is not suppressed. The preset value has a value range of 0.004m / s^2<preset value<0.1m / s^2.

[0112] The present application scheme is further described below according to a specific implementation method:

[0113] In this specific implementation, the wind turbine is a long-bladed wind turbine, a vibration sensor is installed on the nacelle of the wind turbine, and a small diesel generator (20kW) continuously works to supply power to the equipment on the wind turbine. Under the power supply, the controller, pitch drive system, and communication system on the wind turbine operate effectively.

[0114] In this specific implementation, the wind vane installed on the top of the cabin can sense the angle between the incident airflow and the central axis of the sensor, and convert it into an electrical signal, which is sent to the controller. The controller can obtain the cabin wind direction angle based on this.

[0115] The cabin of the wind turbine is equipped with a vibration sensor, which collects the vibration signal of the tower and transmits it to the controller. The vibration signal reflects the real-time vibration acceleration of a single point in the cabin. The vibration acceleration value is cached for 30 seconds and Fourier transformed every 30 seconds. If the maximum amplitude of the signal spectrum in the 0.2Hz to 3.0Hz segment exceeds 0.1m / s^2 after Fourier transformation, it is determined that blade flutter exists at this time, and the method described in the present invention begins to work. Conversely, when the maximum amplitude of the signal spectrum in the 0.2Hz to 3.0Hz segment does not exceed 0.01m / s^2, it is determined that the flutter of the wind turbine is suppressed.

[0116] When the wind turbine flutter is found, the controller reads the cabin wind direction angle. In this specific embodiment, the first angle = 50, the second angle = 120, then if it is found that the cabin wind direction angle is less than 50 degrees or greater than 120 degrees, the speed control pitch change scheme is adopted. On the contrary, if it is found that the cabin wind direction angle is greater than 50 degrees and less than 120 degrees, the pitch change sequence pitch change scheme is adopted.

[0117] In the speed control pitch scheme, the first speed = 1rpm, the second speed = 8rpm, and the preset adjustment angle = 6 degrees. In this specific embodiment, a row of bolts and proximity switches are installed on the main shaft bearing surface of the wind turbine nacelle, so that the wind rotor speed can be directly detected. When the control program is just activated, due to the shutdown of the wind turbine, the speed is equal to 0, which is less than the first speed. The controller controls the pitch angle to reduce a preset adjustment angle (6 degrees), and the pitch angle changes from 89 degrees of the feathering angle to 83 degrees. Then after the first preset detection time (the first preset detection time is set to 10 seconds in this specific embodiment), the wind rotor speed is detected again. If the speed is less than 1rpm, the controller controls the pitch angle to reduce another 6 degrees. When the wind rotor speed is greater than 1rpm, the pitch angle will be stable. After that, if the wind speed increases, it may cause the speed to rise rapidly. In a certain detection, if the speed exceeds 8rpm (the second speed), the controller controls the pitch angle to increase to avoid excessive speed, and then the wind rotor speed is detected again after 10 seconds. In the speed control, when the vibration signal processing program finds that the flutter of the wind turbine is suppressed, the speed control pitch change plan is stopped, and the controller controls the three pitch angles to return to the feathering position (89 degrees in this specific implementation).

[0118] The following implementation method describes the pitch sequence pitch change scheme:

[0119] In the pitch sequence pitch scheme, simulation research on a specific model shows that the maximum span of the interval that causes flutter accumulation is 47 degrees, and the minimum interval is 16 degrees. The pitch angle sequence selected in this scheme is as follows:

[0120] {(pi1,pi2,pi3)|(i=1,2,…n)}={(89,89,10),(76,76,23),(62,62,36),(48,48,49),(34,34,72)}.

[0121] It can be seen that, when n=5, the three preset rules mentioned in the present application method are verified as follows:

[0122] Rule 1:

[0123] p11>p21>p31>p41>p51

[0124] p12>p22>p32>p42>p52

[0125] p13 <p23<p33<p43<p53

[0126] The above pitch angle sequence complies with Rule 1.

[0127] Rule 2:

[0128] Max{p11,p21,p31,p41,p51}-Min{p11,p21,p31,p41,p51}=55>47

[0129] Max{p12,p22,p32,p42,p52}-Min{p12,p22,p32,p42,p52}=55>47

[0130] Max{p13,p23,p33,p43,p53}-Min{p13,p23,p33,p43,p53}=62>47

[0131] It can be seen that the above pitch angle sequence also conforms to Rule 2.

[0132] Rule 3:

[0133] max{abs(p11-p21),abs(p21-p31),abs(p31-p41),abs(p41-p51)}=14<16

[0134] max{abs(p12-p22),abs(p22-p32),abs(p32-p42),abs(p42-p52)}=14<16

[0135] max{abs(p13-p23),abs(p23-p33),abs(p33-p43),abs(p43-p53)}=13<16

[0136] It can be seen that the above pitch angle sequence also complies with Rule 3.

[0137] Therefore, the control of the above sequence is effective. In specific execution, if the flutter of the wind turbine is found, and the wind direction angle of the cabin is between 50 degrees and 120 degrees, the pitch angles of the three blades are first adjusted to (89, 89, 10), and wait for 5 minutes (the second preset detection time in this specific implementation method is 5 minutes). If the flutter is still found after 5 minutes, the pitch angle is continued to be adjusted to (76, 76, 23), and wait for 5 minutes again, and so on, until the blade is moved to (34, 34, 72). According to the design principle, in the above pitch change process, there must be a pitch angle combination. In the waiting process of maintaining the pitch angle, the flutter is suppressed. After the flutter is suppressed, the three pitch angles are controlled to return to the feathering position (89, 89, 89).

[0138] Furthermore, if the wind direction changes suddenly during the propeller movement, the pitch angle interval of the flutter accumulation may change. In this relatively small probability case, after the propeller moves to (34, 34, 72) and waits for more than 5 minutes, the controller finds that the blade flutter still exists, and adjusts the pitch angle to the first sequence value of the pitch angle (89, 89, 10) and repeats the above process. After the flutter is restored, it goes to the feathering position (89, 89, 89).

[0139] The present application first determines the angle between the wind direction and the cabin wind direction of the cabin; then determines whether to use a speed-controlled pitch-changing scheme or a pitch-changing sequence pitch-changing scheme for the pitch-changing operation according to the cabin wind direction angle. By this method, the present application can achieve wind turbine flutter suppression without using yaw when the wind turbine loses power. And by the method of the present application, when the blade azimuth angle is unknown, it is possible to detect whether the flutter is suppressed only by relying on the vibration signal collected by the tower vibration sensor or the blade vibration sensor. Combined with the speed-controlled pitch-changing scheme of the present application to destroy the flutter accumulation condition or the pitch-changing sequence pitch-changing scheme, find the pitch angle that effectively suppresses the flutter.

[0140] Figure 7 A schematic diagram of the structure of a wind turbine flutter suppression device according to an embodiment of the present application is shown. Exemplarily, the wind turbine flutter suppression device comprises:

[0141] The calculation module 10 is used to determine the nacelle wind direction angle between the nacelle orientation of the wind turbine and the wind direction.

[0142] The determination module 20 is used to determine a variable pitch strategy for changing the pitch angle according to the nacelle wind direction angle.

[0143] Wherein, the pitch change strategy includes a speed control pitch change scheme and a pitch change sequence pitch change scheme;

[0144] The speed control pitch change scheme includes: adjusting the pitch angle of the wind turbine blades according to the speed of the wind turbine rotor, so that the wind turbine rotor speed is maintained within a preset speed range until the flutter of the wind turbine is suppressed;

[0145] The pitch sequence pitch scheme includes: performing pitch operation on the wind turbine blades according to a pitch angle sequence in a preset pitch rule until the flutter of the wind turbine is suppressed.

[0146] It can be understood that the device of this embodiment corresponds to the wind turbine flutter suppression method of the above embodiment, and the options in the above embodiment are also applicable to this embodiment, so they will not be described repeatedly here.

[0147] The present application also provides a control system for a wind turbine, comprising a controller and a pitch drive system; the pitch drive system is used to receive instructions from the controller and pitch the blades of the wind turbine; the controller is used to execute the above-mentioned wind turbine flutter suppression method and output control instructions to the pitch drive system.

[0148] The present application also provides a wind turbine generator, including the control system of the wind turbine generator described above.

[0149] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0150] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0151] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk.

[0152] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A method for suppressing flutter of a wind turbine, characterized in that: include: Determine the wind direction angle between the nacelle orientation of the wind turbine and the wind direction; Determine a pitch change strategy for changing the pitch angle according to the cabin wind direction angle; wherein the pitch change strategy includes a speed control pitch change scheme and a pitch change sequence pitch change scheme; The speed control pitch change scheme includes: adjusting the pitch angle of the wind turbine blades according to the speed of the wind turbine rotor, so that the wind turbine rotor speed is maintained within a preset speed range until the flutter of the wind turbine is suppressed; The pitch sequence pitch scheme includes: performing pitch operation on the wind turbine blades according to the pitch angle sequence in the preset pitch rule until the flutter of the wind turbine is suppressed; The pitch change strategy for determining the change of the pitch angle according to the nacelle wind direction angle includes: When the angle of the cabin wind direction angle is less than the first angle or the angle of the cabin wind direction angle is greater than or equal to the second angle, the speed control pitch change scheme is used to change the pitch angle; When the angle of the wind direction of the nacelle is greater than or equal to the first angle and less than the second angle, a pitch angle is changed by using a pitch sequence pitch change scheme; The value range of the first angle is greater than or equal to 40 degrees and less than or equal to 70 degrees; the value range of the second angle is greater than or equal to 110 degrees and less than or equal to 140 degrees.

2. The method for suppressing flutter of a wind turbine according to claim 1, characterized in that: The pitch angle of the wind turbine blades is adjusted according to the wind turbine rotor speed, so that the wind turbine rotor speed is maintained within a preset speed range. include: Wherein, after each adjustment of the pitch angles of the three blades of the wind turbine, a first preset detection time is interval to detect whether the rotation speed of the wind rotor is within the preset rotation speed range; Wherein, the preset speed range refers to between the first speed and the second speed; If it is detected that the rotation speed of the wind rotor is less than the first rotation speed, the pitch angles of the three blades of the wind turbine are respectively reduced by preset adjustment angles; If it is detected that the rotation speed of the wind rotor is greater than the second rotation speed, the pitch angles of the three blades of the wind turbine generator are increased by preset adjustment angles respectively; The relationship between the first speed and the second speed satisfies 0<first speed<second speed<12 rpm.

3. The method for suppressing flutter of a wind turbine according to claim 1, characterized in that: The pitching operation of the wind turbine blades according to the pitch angle sequence in the preset pitching rule comprises: Controlling the three blades of the wind turbine to change the pitch angle to a first sequence value of the pitch angle sequence; Detecting whether the flutter of the wind turbine generator is suppressed at an interval of a second preset detection time; If it is not suppressed, the three blades of the wind turbine are subjected to pitch changing operation according to a preset pitch changing rule, so that the pitch angle is changed to a second sequence value of the pitch angle sequence; After the pitch operation, detecting again at an interval of the second preset detection time whether the flutter of the wind turbine generator is suppressed; If it is not suppressed, continue to perform pitch changing operation on the three blades of the wind turbine according to the preset pitch changing rule, so that the pitch angle is changed to the next sequence value of the pitch angle sequence; The preset pitch change rules include: The pitch angles of the three blades in the pitch angle sequence are increased or decreased in sequence respectively; The difference between the maximum and minimum pitch angles of the same blade in the pitch angle sequence is greater than the maximum value of the pitch angle interval span that generates flutter accumulation; The absolute value of the difference between adjacent sequence values ​​of the pitch angle of the same blade in the pitch angle sequence is smaller than the minimum value of the distance between the pitch angle intervals generating flutter accumulation.

4. The method for suppressing flutter of a wind turbine according to claim 3, characterized in that: The maximum value of the span of the pitch angle interval generating flutter accumulation is greater than 60 degrees; the minimum value of the distance between the pitch angle intervals generating flutter accumulation is less than 35 degrees.

5. The method for suppressing flutter of a wind turbine according to claim 1, characterized in that: The determination of whether the flutter of the wind turbine is suppressed includes: Collect vibration signals from a tower vibration sensor or a blade vibration sensor located on the wind turbine; Performing spectrum analysis on the vibration signal, and extracting the amplitude-frequency component of the vibration signal in the range of 0.2 Hz to 3.0 Hz as the equivalent amplitude; If the equivalent amplitude does not exceed the preset value, it is determined that the flutter of the wind turbine is suppressed, wherein the preset value has a value range of 0.004 m / s^2<preset value<0.1 m / s^2.

6. The method for suppressing flutter of a wind turbine according to any one of claims 1 to 5, characterized in that: After the flutter of the wind turbine generator is suppressed, the method further includes: Controlling the three blades of the wind turbine to return to a feathering position; The feathering position refers to a position where the pitch angle is greater than or equal to 80 degrees and less than or equal to 95 degrees.

7. A wind turbine flutter suppression device, characterized in that: include: A calculation module, used to determine a cabin wind direction angle between a cabin orientation of a wind turbine and a wind direction; A determination module, used to determine a variable pitch strategy for changing the pitch angle according to the nacelle wind direction angle; Wherein, the pitch change strategy includes a speed control pitch change scheme and a pitch change sequence pitch change scheme; The speed control pitch change scheme includes: adjusting the pitch angle of the wind turbine blades according to the speed of the wind turbine rotor, so that the wind turbine rotor speed is maintained within a preset speed range until the flutter of the wind turbine is suppressed; The pitch sequence pitch scheme includes: performing pitch operation on the wind turbine blades according to the pitch angle sequence in the preset pitch rule until the flutter of the wind turbine is suppressed; The pitch change strategy for determining the change of the pitch angle according to the nacelle wind direction angle includes: When the angle of the cabin wind direction angle is less than the first angle or the angle of the cabin wind direction angle is greater than or equal to the second angle, the speed control pitch change scheme is used to change the pitch angle; When the angle of the wind direction of the nacelle is greater than or equal to the first angle and less than the second angle, a pitch angle is changed by using a pitch sequence pitch change scheme; The value range of the first angle is greater than or equal to 40 degrees and less than or equal to 70 degrees; the value range of the second angle is greater than or equal to 110 degrees and less than or equal to 140 degrees.

8. A control system for a wind turbine, characterized in that: Including controller and pitch drive system; The variable pitch drive system is used to receive instructions from the controller and change the pitch of the blades of the wind turbine; The controller is used to execute the wind turbine flutter suppression method according to any one of claims 1 to 6 and output control instructions to the variable pitch drive system.

9. A wind turbine, characterized in that: A control system for a wind turbine generator comprising the control system of claim 8.

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