A fan control method to improve the stability of high towers of large-capacity units

Abstract

The present invention provides a wind turbine control method for improving the stability of high-tower wind turbines of large-capacity units, which relates to the field of wind turbine control technology. Its purpose is to reduce the operating safety risk of the wind turbine tower under complex terrain and wind field conditions. After the first adjustment is completed, the wind direction control angle of each blade is adjusted twice. The method is characterized by including establishing a global coordinate system; setting a unit monitoring area with the same position at the root of each blade, taking its geometric center as a reference point, and obtaining the initial coordinates of each reference point; obtaining the current rotation angle α of each blade around the wind rotor i The current coordinates of each reference point are calculated based on the initial coordinates and rotation angle; the vibration amplitude of each unit monitoring area is collected; and the wind direction control angle of each blade is adjusted based on the current coordinates and vibration amplitude of each reference point. This invention has the advantages of improving the balance performance of the wind turbine and extending the tower life.

Description

Technical Field

[0001] The present invention relates to the field of fan control technology, and in particular to a fan control method for improving the stability of a high tower of a large-capacity unit. Background Art

[0002] With the promotion and development of wind power generation, the capacity of wind turbines has increased and the height of wind turbine towers has become a development trend. The wind turbine tower mainly plays a supporting role in the wind turbine generator set and also absorbs the vibration of the unit.

[0003] During wind turbine operation, the blades transmit aerodynamic loads acting on their swept areas and the torque generated by their rotation to the tower. Due to the large diameter of the blades, the wind speed at the upper end of the blade's swept area differs from that at the lower end. This uneven wind speed distribution and shifting wind direction generate deflecting forces, deflecting moments, and pitching moments. Because the rotating blades can automatically adjust their orientation to the wind with changing wind direction through pitch control, the blades rotate about the tower axis, subjecting the tower to gyroscopic forces and gyroscopic moments. Furthermore, in actual operation, due to various interference factors and operational variations, each blade experiences different wind pressures, resulting in varying directions and magnitudes of force at its base. This variability exacerbates the unbalanced pull on the wind tower, leading to long-term tower degradation and even reduced service life, increasing safety risks for the wind turbine.

[0004] In order to reduce the operating safety risks of the tower under complex terrain and wind field conditions, it is necessary to further optimize the control method of the wind turbine blades to improve their balance and stability. Summary of the Invention

[0005] The purpose of the present invention is to provide a wind turbine control method for improving the stability of high towers of large-capacity units, and its purpose is to reduce the operating safety risks of the towers under complex terrain and wind field conditions.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] A wind turbine control method for improving the stability of high-tower large-capacity units periodically adjusts the wind direction control angle of each blade using a pitch control mechanism based on the current wind speed and direction. The wind direction control angle changes the blade's angle of attack. After a time t0 after the completion of the first adjustment, the wind direction control angle of each blade is adjusted a second time. The secondary adjustment includes the following steps:

[0008] Establish a global coordinate system: take the center of the circle on the end face of the wind rotor as the origin; take the center of the circle as the starting point, and the horizontal ray pointing forward along the axis of the wind rotor as the y-axis; take the center of the circle as the starting point, and the horizontal ray perpendicular to the axis of the wind rotor pointing to the right as the y-axis;

[0009] A unit monitoring area with the same position is set at the root of each blade, and its geometric center is taken as the reference point to obtain the initial coordinates P of each reference point. oi , i is the number of the corresponding leaf;

[0010] Get the current rotation angle α of each blade around the wind wheel i ;

[0011] Calculate the current coordinate P of each reference point according to the initial coordinate and the rotation angle real-i ;

[0012] Collect the vibration amplitude of each unit monitoring area;

[0013] The wind direction control angle of each blade is adjusted respectively according to the current coordinates and vibration amplitude of each reference point.

[0014] Preferably, the t0 is 10-25 seconds.

[0015] Preferably, the reference point is located on the central axis of the corresponding blade along the length direction of the blade.

[0016] Preferably, the method for obtaining the initial coordinates of the reference point is:

[0017] Perform attitude initialization, and at the initial moment, blade 1 overlaps with the positive half axis of the z axis;

[0018] Reference point coordinates P of blade No. 1 o1 is (0, 0, z o1 ), z o1 is the distance from the reference point to the origin;

[0019] n is the total number of leaves, numbered clockwise starting from leaf 1, and the base point coordinates of leaf i are P oi for:

[0020] P o i=R y (θ)*P o1 T , θ=(i-1)*θ0;

[0021] θ0=2*π / n;

[0022]

[0023] Preferably, the method for obtaining the current rotation angle of each blade around the wind wheel is to set a rotation angle sensor in each unit monitoring area.

[0024] Preferably, the calculation of the current coordinates P of each reference point real-i The method is:

[0025] P real-i =R y (α i )*P oi T ;

[0026]

[0027] Preferably, the method for collecting the vibration amplitude of each unit monitoring area is to set a vibration sensor in the unit monitoring area.

[0028] Preferably, the method of adjusting the wind direction control angle of each blade according to the current coordinates and vibration amplitude of each reference point is:

[0029] Get the reference point vector, which is the vector from the origin to the corresponding reference point;

[0030] Calculate the angle γ between all adjacent reference point vectors j , j=1,…,n-1 j is the angle between the reference point vectors of blade j and blade j+1, and when j=n, γ j is the angle between the reference point vectors of blade n and blade 1;

[0031] Judgment j Which angles are greater than the first angle threshold?

[0032] When γ k When the angle is greater than the first angle threshold, the vibration amplitudes of the two corresponding blades are checked. If the difference between the vibration amplitudes of the two blades is greater than the amplitude threshold, the blade with the larger vibration amplitude is selected to adjust the wind direction control angle.

[0033] Preferably, a deformation detection device is provided in the middle section of each blade, and when the deformation of the middle section of the blade exceeds a deformation threshold, the wind direction control angle of the blade is adjusted; the deformation detection device adopts a strain gauge.

[0034] Preferably, the method for adjusting the wind direction control angle is to change the wind direction control angle through a pitch mechanism to reduce the angle of attack.

[0035] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0036] The present invention adjusts the blade's angle of attack according to wind direction and speed based on traditional variable pitch control, which firstly ensures the basic operating quality of the wind turbine;

[0037] This invention optimizes the traditional pitch angle adjustment method, improves the balance between blades, reduces the uneven force acting on the tower, and can effectively reduce the operating safety risk of the tower under different wind field conditions.

[0038] The present invention can extend the practical life of the wind turbine tower and help save the maintenance cost of wind power generation equipment;

[0039] The present invention collects vibration data and deformation in a simple and accurate manner, and can also accurately reflect the potential risk of unbalanced force caused by the blades on the tower, so as to adjust the wind turbine control strategy in a timely manner;

[0040] The present invention has reasonable design, simple data collection and processing, low calculation cost and involved construction cost, and is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 A schematic diagram of a method flow chart provided in an embodiment of the present invention;

[0043] Figure 2 Schematic diagram of establishing the coordinate system provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of 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. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0046] Example 1

[0047] See Figure 1-Figure 2This embodiment provides a wind turbine control method for improving the stability of a high-tower large-capacity unit. The method periodically adjusts the wind direction control angle of each blade using a pitch mechanism according to the current wind speed and wind direction. The wind direction control angle changes the blade's angle of attack. After a time t0 after the completion of the first adjustment, the wind direction control angle of each blade is adjusted a second time. The second adjustment includes the following steps:

[0048] Step S1: Establish a global coordinate system with the center of the circle on the end face of the wind rotor as the origin; with the center of the circle as the starting point, the horizontal ray pointing forward along the axis of the wind rotor is the y-axis; with the center of the circle as the starting point, the horizontal ray pointing to the right perpendicular to the axis of the wind rotor is the y-axis; the method of establishing the coordinate system can be found in Figure 2 , in particular, Figure 2 The leaves are omitted to better illustrate the lines of the coordinate system;

[0049] Step S2: Set a unit monitoring area with the same position at the root of each blade, take its geometric center as the reference point, and obtain the initial coordinates P of each reference point oi , i is the number of the corresponding leaf;

[0050] Step S3: Obtain the current rotation angle α of each blade around the wind wheel i ;

[0051] Step S4: Calculate the current coordinates P of each reference point based on the initial coordinates and the rotation angle real-i ;

[0052] Step S5: collecting the vibration amplitude of each unit monitoring area;

[0053] Step S6: adjusting the wind direction control angle of each blade according to the current coordinates and vibration amplitude of each reference point.

[0054] As a preferred solution of this embodiment, the t0 is 10-25 seconds.

[0055] The principles of this embodiment are as follows:

[0056] When generating electricity through wind power, it is necessary to control the angle of attack of the wind turbine blades, which can affect the overall performance, power generation efficiency and life of the wind turbine. Specifically, during the operation of the wind turbine to generate electricity, it is necessary to adjust the angle of attack of the blades according to the wind speed and wind direction parameters to achieve higher wind power utilization efficiency. Specifically, the angle of attack refers to the angle of the blade relative to the wind direction, which can be controlled by a variable pitch mechanism. In traditional control schemes, when the wind speed changes, the variable pitch mechanism will automatically adjust the blade angle to keep the blade angle of attack within an appropriate range, thereby achieving the maximum power output of the wind turbine.

[0057] The improvement of this embodiment is based on the optimization of the above traditional pitch control. This embodiment first selects a reference point for each blade. The coordinate position of this reference point represents the position of the blade. Based on the position of the blade, the offset can be determined, and then the blades requiring risk control angle adjustment can be determined. The specific calculation method can be optimized in subsequent embodiments.

[0058] Example 2

[0059] This embodiment is based on the technical solution of Embodiment 1 and further explains the acquisition of the position of the reference point related to step S2.

[0060] In this embodiment, the reference point is located on the central axis of the corresponding blade along the length direction of the blade.

[0061] As a preferred solution, the method for obtaining the initial coordinates of the reference point is:

[0062] Perform attitude initialization, and at the initial moment, blade 1 overlaps with the positive half axis of the z axis;

[0063] Reference point coordinates P of blade No. 1 o1 is (0, 0, z o1 ), z o1 is the distance from the reference point to the origin;

[0064] n is the total number of leaves, numbered clockwise starting from leaf 1, and the base point coordinates of leaf i are P oi for:

[0065] P oi =R y (θ)*P o1 T , θ=(i-1)*θ0;

[0066] θ0=2*π / n;

[0067]

[0068] On the other hand, the method for obtaining the current rotation angle of each blade around the wind wheel is to set a rotation angle sensor in each unit monitoring area.

[0069] Furthermore, the calculation of the current coordinates P of each reference point real-i The method is:

[0070] P real-i =R y (α i )*P oi T ;

[0071]

[0072] In this embodiment, the position of the reference point is used to represent the position of the blade, which facilitates the subsequent estimation of the posture relationship between different blades.

[0073] The basic calculation principle of this embodiment is the rotation matrix. When initially obtaining the initial position, the reference point of blade 1 is directly obtained, and the positions of the other blades are then calculated as their rotated positions. The rotation distance between each adjacent blade is determined by the arrangement of the blades themselves. For example, in the case of three blades, blade 2 is equivalent to the position of blade 1 after rotating 120 degrees, and blade 3 is equivalent to the position of blade 1 after rotating 240 degrees.

[0074] Finally, when calculating the current position of each blade, the rotation angle is directly obtained and then calculated through the rotation matrix.

[0075] The above two rotations are both about the y-axis, so it is also easy to obtain the rotation matrix for coordinate calculation.

[0076] Example 3

[0077] This embodiment is based on the technical solution of Implementation 1 and further explains the adjustment of the wind direction control angle in steps S3-S6.

[0078] As a preferred solution of this embodiment, the method for collecting the vibration amplitude of each unit monitoring area is to set a vibration sensor in the unit monitoring area.

[0079] In a specific implementation, the method of adjusting the wind direction control angle of each blade according to the current coordinates and vibration amplitude of each reference point can be selected as follows:

[0080] Get the reference point vector, which is the vector from the origin to the corresponding reference point;

[0081] Calculate the angle γ between all adjacent reference point vectors j , j=1,…,n-1 j is the angle between the reference point vectors of blade j and blade j+1, and when j=n, γ j is the angle between the reference point vectors of blade n and blade 1;

[0082] Judgment j Which angles are greater than the first angle threshold?

[0083] When γ kWhen the angle is greater than the first angle threshold, the vibration amplitudes of the two corresponding blades are checked. If the difference between the vibration amplitudes of the two blades is greater than the amplitude threshold, the blade with the larger vibration amplitude is selected to adjust the wind direction control angle.

[0084] Finally, the method for adjusting the wind direction control angle in this embodiment is to change the wind direction control angle by using a pitch mechanism to reduce the angle of attack.

[0085] The core idea of this embodiment is as follows:

[0086] The vector from the origin to the reference point can represent the basic posture of the corresponding blade, which is equivalent to the position the blade rotates to and the direction of the blade tip. Therefore, the angle between two adjacent blades can be obtained by calculating the angle between the vectors of two adjacent reference points. When the angle between two adjacent blades is too large, it means that there is a high possibility that the forces between the two blades are unbalanced. Therefore, the vibration data can be checked, because the vibration data is also a parameter that can well reflect the wind force that the blade withstands. Here, when the amplitude difference between the two blades is too large, it is judged that the imbalance is indeed caused by the difference in force and the angle is too large. Therefore, the one with the larger vibration amplitude is selected for adjustment to reduce the force to achieve balanced regulation.

[0087] The specific control strategy invention is that when the blade's angle of attack increases, the impact of the wind on the blade also increases, resulting in greater load and flexural stress on the blade. When the blade's angle of attack increases to a certain extent, the wind speed at its tip may exceed the air speed, causing shearing, at which point the blade will lose control and become dangerous. In the control scheme of this embodiment, since the blade with a large vibration amplitude needs to reduce its force, the wind direction control angle is changed by the pitch mechanism to reduce the angle of attack.

[0088] It is important to note that the sum of all adjacent angles must be 360 degrees. Here, only those angles that have increased are adjusted, because if the total degree remains unchanged, then one angle must have decreased. Addressing only one of these situations can resolve the problem of uneven force on the blades. By adjusting the increased angle back to normal, the decreased angle will naturally return to normal. Therefore, it is also possible to select adjacent blades with angles below a preset threshold for control.

[0089] Example 4

[0090] This embodiment is based on the technical solution of Implementation 1 and further optimizes the adjustment of the control solution.

[0091] In this embodiment, a deformation detection device is further provided in the middle section of each blade. When the deformation of the middle section of the blade exceeds a deformation threshold, the wind direction control angle of the blade is adjusted. The deformation detection device adopts a strain gauge.

[0092] In addition to blade root stress, this embodiment also considers blade deformation to provide additional protection. Excessive force on some blades, exceeding a preset threshold, can accelerate wear of the entire turbine, such as the tower. Therefore, blade deformation monitoring further mitigates safety risks for the entire wind turbine.

[0093] In addition, the method for adjusting the wind direction control angle in this embodiment is also to change the wind direction control angle by using the pitch mechanism to reduce the angle of attack. The principle is the same as that of the above embodiment 3, which mainly changes the wind direction control angle by using the pitch mechanism to reduce the angle of attack, thereby reducing the corresponding force on the blades and alleviating their deformation.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A wind turbine control method for improving the stability of high-tower large-capacity units, wherein the wind direction control angle of each blade is periodically adjusted based on the current wind speed and direction through a pitch control mechanism. The wind direction control angle changes the blade's angle of attack. After a time t0 after the completion of the first adjustment, the wind direction control angle of each blade is adjusted a second time. The method is characterized in that: The secondary adjustment includes the following steps: Establish a global coordinate system: take the center of the circle on the end face of the wind rotor as the origin; take the center of the circle as the starting point, and the horizontal ray pointing forward along the axis of the wind rotor as the y-axis; take the center of the circle as the starting point, and the horizontal ray pointing to the right perpendicular to the axis of the wind rotor as the x-axis; A unit monitoring area with the same position is set at the root of each blade, and its geometric center is taken as the reference point to obtain the initial coordinates P of each reference point. oi , i is the number of the corresponding leaf; Get the current rotation angle α of each blade around the wind wheel i ; Calculate the current coordinate P of each reference point according to the initial coordinate and the rotation angle real-i ; Collect the vibration amplitude of each unit monitoring area; adjusting the wind direction control angle of each blade according to the current coordinates and vibration amplitude of each reference point; The method for adjusting the wind direction control angle of each blade according to the current coordinates and vibration amplitude of each reference point is as follows: Get the reference point vector, which is the vector from the origin to the corresponding reference point; Calculate the angle γ between all adjacent reference point vectors j , j=1,…,n-1 j is the angle between the reference point vectors of blade j and blade j+1, and when j=n, γ j is the angle between the reference point vectors of blade n and blade 1; Judgment j Which angles are greater than the first angle threshold? When γ k When the angle is greater than the first angle threshold, the vibration amplitudes of the two corresponding blades are checked. If the difference between the vibration amplitudes of the two blades is greater than the amplitude threshold, the blade with the larger vibration amplitude is selected to adjust the wind direction control angle.

2. A wind turbine control method for improving the stability of a high tower of a large-capacity unit according to claim 1, characterized in that: The t0 is 10-25 seconds.

3. A wind turbine control method for improving the stability of a high tower of a large-capacity unit according to claim 1, characterized in that: The reference point is located on the central axis of the corresponding blade along the length direction of the blade.

4. The wind turbine control method for improving the stability of a high tower of a large-capacity unit according to claim 1, characterized in that: The method for obtaining the current rotation angle of each blade around the wind wheel is to set a rotation angle sensor in each unit monitoring area.

5. A wind turbine control method for improving the stability of a high tower of a large-capacity unit according to claim 1, characterized in that: The method for collecting the vibration amplitude of each unit monitoring area is to set a vibration sensor in the unit monitoring area.

6. A wind turbine control method for improving the stability of a high tower of a large-capacity unit according to claim 1, characterized in that: A deformation detection device is also provided in the middle section of each blade. When the deformation of the middle section of the blade exceeds a deformation threshold, the wind direction control angle of the blade is adjusted. The deformation detection device adopts a strain gauge.

7. A wind turbine control method for improving the stability of a high tower of a large-capacity unit according to claim 1 or 6, characterized in that: The method for adjusting the wind direction control angle is to change the wind direction control angle through a pitch mechanism to reduce the angle of attack.

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