Control method and system for reducing load of wind turbine under extreme wind shear working condition

Abstract

The application discloses a control method and system for reducing load of a wind turbine under extreme wind shear conditions, wherein the method is to acquire the front and rear loads of a yaw bearing of the wind turbine through a load sensor, analyze the variation trend of the front and rear loads of the yaw bearing, identify whether the wind turbine has encountered the extreme wind shear conditions, and if so, apply a pitch control command, so as to reduce the load of the main components of the wind turbine and improve the safety of the wind turbine. The application can effectively identify the extreme wind shear conditions, so as to reduce the load through corresponding control means, improve the adaptability of the wind turbine to the external extreme wind conditions, and solve the problem of excessive load of the main components (such as the bending moment of the yaw and the hub) of the wind turbine when the wind turbine encounters the extreme wind shear conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation, in particular to a control method and system for reducing the load of a wind turbine under extreme wind shear conditions, a storage medium and a computing device. BACKGROUND

[0002] With the continuous increase in the single capacity of wind turbines, the weight and area of the impeller of the wind turbine are also increasing, and controlling the extreme load of the wind turbine has become a major bottleneck in the development of the wind turbine and a major test of the safety of the wind turbine.

[0003] Extreme wind shear conditions are an extreme condition defined by IEC standards, which represents a certain difference in wind speed at different heights, and has two forms of horizontal wind shear (horizontal increase or decrease) and vertical wind shear (vertical increase or decrease). At this time, the impeller of the wind turbine bears unbalanced external excitation, which increases the overturning moment of the wind turbine, and thus the component load of the wind turbine increases sharply. If the load exceeds the bearing capacity of the wind turbine, it will cause adverse consequences such as blade breakage and wind turbine damage.

[0004] At present, research on identifying extreme wind shear conditions is still relatively rare, and most of them rely on laser radar wind measurement, but laser radar is expensive and the identification effect is unstable. And with the increasing cost pressure of wind turbines, a low-cost and high-efficiency control method to deal with extreme wind shear conditions has become an important demand. SUMMARY

[0005] The first object of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a safe and reliable control method for reducing the load of a wind turbine under extreme wind shear conditions, which can effectively identify extreme wind shear conditions, and thus perform corresponding control means to reduce the load, improve the adaptability of the wind turbine to extreme wind conditions, and solve the problem of excessive load of large components (such as yaw and hub bending moment) of the wind turbine when encountering extreme wind shear conditions.

[0006] The second object of the present application is to provide a control system for reducing the load of a wind turbine under extreme wind shear conditions.

[0007] The third object of the present application is to provide a storage medium.

[0008] The fourth object of the present application is to provide a computing device.

[0009] The first object of the application is achieved by the following technical solution: a control method for reducing the load of a wind turbine under extreme wind shear conditions, which obtains the front and rear loads of the yaw bearing of the wind turbine through a load sensor, analyzes the change trend of the front and rear loads of the yaw bearing, identifies whether the wind turbine has encountered an extreme wind shear condition, and if so, applies a pitch command to reduce the load of the major components of the wind turbine and improve the safety of the wind turbine.

[0010] Further, the control method for reducing the load of a wind turbine under extreme wind shear conditions comprises the following steps:

[0011] 1) Read the load sensor information, obtain the front and rear loads of the yaw bearing of the wind turbine and perform filtering processing;

[0012] 2) Determine whether the filtered load value is greater than the first load threshold value, if so, execute step 3), otherwise jump back to step 1);

[0013] 3) Determine whether the change rate of the front and rear loads of the yaw bearing is greater than the first change rate threshold value, if so, start timer 1, and when the duration exceeds the first time threshold value, determine whether the change rate of the front and rear loads of the yaw bearing during the period is greater than the second change rate threshold value, if so, execute step 4), if not, clear timer 1 and jump back to step 1); wherein the second threshold value is greater than the first threshold value;

[0014] 4) Determine whether the pitch angle of the wind turbine is greater than the pitch angle threshold value, if so, execute step 5), otherwise jump back to step 1);

[0015] 5) Determine whether the generator speed of the wind turbine is greater than the speed threshold value, if so, execute step 6), otherwise jump back to step 1);

[0016] 6) Determine whether the wind speed of the wind turbine is greater than the wind speed threshold value, if so, set the extreme wind shear flag to true, start timer 2, and execute step 7), otherwise jump back to step 1);

[0017] 7) Add an additional pitch angle to the output of the pitch PID controller of the wind turbine, determine whether timer 2 is greater than the maximum time threshold value of the strategy action, if so, do not add the additional pitch action, reset the extreme wind shear flag to false, and clear timer 2, otherwise add an additional pitch angle to the output of the pitch PID controller.

[0018] Furthermore, in step 1), the load sensor is installed in the front-to-rear direction of the yaw bearing of the wind turbine generator or in the top tower of the wind turbine generator; if the load sensor is installed in the front-to-rear direction of the yaw bearing, the front-to-rear load of the yaw bearing can be directly obtained for use; if the load sensor is installed in the top tower, it is necessary to install it in the front-to-rear direction and left-to-right direction of the tower top respectively, and simultaneously obtain the front-to-rear load and side load of the tower top, and then convert it into the front-to-rear load of the yaw bearing using the formula, which is as follows:

[0019] My yawbearing =Mz towertop *cosγ+My towertop *sinγ

[0020] In the formula, My yawbearing is the front and rear load of the yaw bearing, Mz towertop is the front and rear loads on the tower top, My towertop is the lateral load on the tower top, and γ is the angle of the wind turbine to the north.

[0021] Furthermore, in step 1), after obtaining the front and rear loads of the yaw bearing, the load values ​​need to be filtered, including low-pass filtering and notch processing for the 3P frequency.

[0022] Furthermore, in step 3), the yaw bearing front and rear load change rate is calculated using the load measurement values ​​at the current moment and the previous moment.

[0023] Furthermore, in step 4), the pitch angle sensor information of the wind turbine is read, the pitch angles of all blades of the wind turbine are obtained and averaged, and then it is determined whether the average is greater than a pitch angle threshold.

[0024] Furthermore, in step 5), the generator speed slip ring sensor information of the wind turbine is read. In order to obtain smoother speed information and prevent misjudgment caused by speed jumps, the sensor signal is filtered, including low-pass filtering and notching at multiple frequency points, and then it is determined whether the generator speed after filtering is greater than the speed threshold.

[0025] Furthermore, in step 6), the wind speed sensor information of the wind turbine is read, an average value of multiple wind speed sensors is obtained, and then it is determined whether the average value is greater than a wind speed threshold.

[0026] Furthermore, in step 7), the wind turbine can be retracted more quickly by superimposing an additional pitch angle, wherein the additional pitch angle is a unified retracting action or an independent retracting instruction for each blade based on the impeller azimuth angle.

[0027] The second object of the application is achieved by the following technical solution: a control system for reducing the load of a wind turbine under extreme wind shear conditions, used to implement the control method for reducing the load of a wind turbine under extreme wind shear conditions described above, comprising:

[0028] A load acquisition and filtering module is configured to read load sensor information, acquire the front and rear loads of the yaw bearing of the wind turbine, and perform filtering processing.

[0029] A first judgment module is configured to judge whether the filtered load value is greater than a first load threshold value, if yes, execute a second judgment module, otherwise jump back to the load acquisition and filtering module.

[0030] The second judgment module is configured to judge whether the front and rear load change rate of the yaw bearing is greater than a first change rate threshold value, if yes, timer 1 starts timing, and when the duration exceeds a first time threshold value, judge whether the front and rear load change rate of the yaw bearing during the period is greater than a second change rate threshold value, if yes, execute a third judgment module, if not, timer 1 is cleared, and jump back to the load acquisition and filtering module; wherein the second threshold value is greater than the first threshold value.

[0031] The third judgment module is configured to judge whether the pitch angle of the wind turbine is greater than a pitch angle threshold value, if yes, execute a fourth judgment module, otherwise jump back to the load acquisition and filtering module.

[0032] The fourth judgment module is configured to judge whether the generator speed of the wind turbine is greater than a speed threshold value, if yes, execute a fifth judgment module, otherwise jump back to the load acquisition and filtering module.

[0033] The fifth judgment module is configured to judge whether the wind speed of the wind turbine is greater than a wind speed threshold value, if yes, the extreme wind shear flag is set to true, timer 2 starts timing, and the load reduction control module is executed, otherwise jump back to the load acquisition and filtering module.

[0034] The load reduction control module is configured to superimpose an additional pitch angle on the output of the pitch PID controller of the wind turbine, judge whether timer 2 is greater than a maximum strategy action time threshold value, if yes, no longer superimpose the additional pitch action, reset the extreme wind shear flag to false, and clear timer 2, otherwise superimpose an additional pitch angle on the output of the pitch PID controller again.

[0035] The third object of the application is achieved by the following technical solution: a storage medium storing a program, which is executed by a processor to implement the control method for reducing the load of a wind turbine under extreme wind shear conditions described above.

[0036] The fourth object of the present application is achieved by the following technical solution: a computing device comprising a processor and a memory for storing a program executable by the processor, wherein the processor implements the control method for reducing the load of a wind turbine under extreme wind shear conditions when executing the program stored in the memory.

[0037] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0038] 1. The algorithm of the present application is simple and efficient, and can effectively identify extreme wind shear conditions, thereby reducing the load through corresponding control means and improving the adaptability of the wind turbine to extreme wind conditions, providing feasibility for subsequent control, which is extremely rare in existing research results.

[0039] 2. The present application can effectively reduce the load of the large components of the wind turbine under extreme wind shear conditions, improve the safety of the unit, and reduce the design cost of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The flowchart of the method of the present application.

[0041] Figure 2 The pitch curve.

[0042] Figure 3 The speed curve.

[0043] Figure 4 The hub bending moment curve.

[0044] Figure 5 The yaw bending moment curve.

[0045] Figure 6 The architecture diagram of the system of the present application. DETAILED DESCRIPTION

[0046] The present application will be described in further detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present application are not limited thereto.

[0047] Example 1

[0048] This embodiment discloses a control method for reducing the load of a wind turbine under extreme wind shear conditions, which obtains the front and rear loads of the yaw bearing of the wind turbine through a load sensor, analyzes the change trend of the front and rear loads of the yaw bearing, identifies whether the wind turbine has encountered extreme wind shear conditions, and if so, applies a pitch collection instruction, thereby reducing the load of the large components of the wind turbine and improving the safety of the wind turbine, as shown in Figure 1 The method comprises the following steps:

[0049] 1) read the load sensor information, get the yaw bearing front and rear load of the wind turbine and filter processing, the load sensor can be installed in the front and rear direction of the yaw bearing of the wind turbine or installed in the top layer of the tower of the wind turbine; if the load sensor is installed in the front and rear direction of the yaw bearing, the yaw bearing front and rear load can be directly obtained for use; if the load sensor is installed in the top layer of the tower, it is necessary to be installed in the front and rear direction and left and right direction of the top layer of the tower respectively, and the front and rear load and lateral load of the top layer of the tower are obtained, and then the yaw bearing front and rear load is converted through the formula, the formula is as follows:

[0050] My yawbearing = Mz towertop *cosγ + My towertop *sinγ

[0051] In the formula, My yawbearing is the yaw bearing front and rear load, Mz towertop is the top front and rear load, My towertop is the top lateral load, and γ is the angle of the wind turbine to north.

[0052] After obtaining the yaw bearing front and rear load, the load value needs to be filtered, including low-pass filtering and notch processing for 3P frequency.

[0053] 2) judge whether the filtered load value is greater than the first load threshold value, if yes, execute step 3), otherwise jump back to step 1);

[0054] 3) calculate the yaw bearing front and rear load change rate, the yaw bearing front and rear load change rate can be calculated through the load measurement value at the current time and the previous time, then judge whether the yaw bearing front and rear load change rate is greater than the first change rate threshold value, if yes, timer 1 starts timing, and when the duration exceeds the first time threshold value, judge whether the yaw bearing front and rear load change rate during the period is greater than the second change rate threshold value, if yes, execute step 4), if not, timer 1 is cleared and jumps back to step 1); wherein the second threshold value is greater than the first threshold value;

[0055] 4) read the pitch angle sensor information of the wind turbine, get the pitch angle of all blades of the wind turbine and take the average value, then judge whether the average value is greater than the pitch angle threshold value, if yes, execute step 5), otherwise jump back to step 1);

[0056] 5) read the generator speed slip ring sensor information of the wind turbine, in order to obtain smoother speed information and prevent misjudgment caused by speed jump, filter the sensor signal, including low-pass filtering and notch at multiple frequency points, then judge whether the filtered generator speed is greater than the speed threshold value, if yes, execute step 6), otherwise jump back to step 1);

[0057] 6) read the wind speed sensor information of the wind turbine, take the average of multiple wind speed sensors, and then determine whether the average is greater than the wind speed threshold value, if yes, the extreme wind shear flag is set to true, timer 2 starts timing, and step 7) is executed, otherwise, jump back to step 1);

[0058] 7) superimpose an additional pitch angle on the output of the pitch PID controller of the wind turbine to make the wind turbine pitch faster, the additional pitch angle can be a unified pitch action or an independent pitch instruction based on the azimuth angle of the impeller; then determine whether timer 2 is greater than the maximum time threshold value of the strategy action, if yes, do not superimpose the additional pitch action, reset the extreme wind shear flag to false, and clear timer 2, otherwise, superimpose an additional pitch angle on the output of the pitch PID controller again.

[0059] Referring to Figures 2 to 5 , the running states of the extreme wind shear working condition with or without using the strategy of the application are shown. As can be seen from the figure, the experimental group effectively identifies the extreme wind shear working condition under the same extreme wind shear working condition, and controls the generator speed of the wind turbine to be smaller through the additional pitch action, and the limit load of the hub bending moment and the yaw bending moment is significantly reduced.

[0060] Embodiment 2

[0061] The embodiment discloses a control system for reducing the load of a wind turbine in an extreme wind shear working condition, which is used to realize the control method for reducing the load of a wind turbine in an extreme wind shear working condition as described in embodiment 1, as shown in Figure 6 , the system comprises the following functional modules:

[0062] The load acquisition and filtering module is used to read the load sensor information, acquire the front and rear loads of the yaw bearing of the wind turbine, and perform filtering processing;

[0063] The first judgment module is used to determine whether the filtered load value is greater than the first load threshold value, if yes, execute the second judgment module, otherwise, jump back to the load acquisition and filtering module;

[0064] The second judgment module is used to determine whether the yaw bearing front and rear load change rate is greater than the first change rate threshold value, if yes, timer 1 starts timing, and when the duration exceeds the first time threshold value, determine whether the yaw bearing front and rear load change rate during the period is greater than the second change rate threshold value, if yes, execute the third judgment module, if no, clear timer 1, and jump back to the load acquisition and filtering module; wherein the second threshold value is greater than the first threshold value;

[0065] The third judging module is configured to judge whether the pitch angle of the wind turbine is greater than a pitch angle threshold value, if yes, execute the fourth judging module, otherwise jump back to the load acquisition and filtering module.

[0066] The fourth judging module is configured to judge whether the generator speed of the wind turbine is greater than a speed threshold value, if yes, execute the fifth judging module, otherwise jump back to the load acquisition and filtering module.

[0067] The fifth judging module is configured to judge whether the wind speed of the wind turbine is greater than a wind speed threshold value, if yes, the extreme wind shear flag is set to true, the timer 2 starts timing, and the load reduction control module is executed, otherwise jump back to the load acquisition and filtering module.

[0068] The load reduction control module is configured to superimpose an additional pitch angle on the output of the pitch PID controller of the wind turbine, judge whether the timer 2 is greater than a maximum action time threshold value, if yes, no longer superimpose the additional pitch action, the extreme wind shear flag is reset to false, and the timer 2 is cleared, otherwise superimpose an additional pitch angle on the output of the pitch PID controller again.

[0069] Embodiment 3

[0070] The embodiment discloses a storage medium, which stores a program, and when the program is executed by a processor, the control method for reducing the load of the wind turbine in the extreme wind shear working condition in the embodiment 1 is realized.

[0071] The storage medium in the embodiment can be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a U disk, a mobile hard disk, and the like.

[0072] Embodiment 4

[0073] The embodiment discloses a computing device, which comprises a processor and a memory for storing a program executable by the processor, and when the processor executes the program stored in the memory, the control method for reducing the load of the wind turbine in the extreme wind shear working condition in the embodiment 1 is realized.

[0074] The computing device in the embodiment can be a desktop computer, a notebook computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with a processor function.

[0075] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement manners and should be included in the protection scope of the present application.

Claims

1. A control method for reducing wind turbine load under extreme wind shear conditions, characterized in that: The method uses a load sensor to obtain the front and rear loads of the yaw bearing of the wind turbine, and then analyzes the changing trend of the front and rear loads of the yaw bearing to identify whether the wind turbine encounters extreme wind shear conditions. If so, a blade retraction command is applied to reduce the load on the large components of the wind turbine and improve the safety of the wind turbine. The method includes the following steps: 1) Read the load sensor information, obtain the front and rear loads of the yaw bearing of the wind turbine and perform filtering; 2) Determine whether the filtered load value is greater than the first load threshold. If so, execute step 3); otherwise, jump back to step 1); 3) Determine whether the rate of change of the yaw bearing front and rear load is greater than a first rate of change threshold. If so, start timer 1. When the duration exceeds the first time threshold, determine whether the rate of change of the yaw bearing front and rear load during the period is greater than a second rate of change threshold. If so, execute step 4). If not, reset timer 1 and jump back to step 1); wherein the second threshold is greater than the first threshold. 4) Determine whether the pitch angle of the wind turbine generator set is greater than the pitch angle threshold. If so, execute step 5), otherwise jump back to step 1); 5) Determine whether the generator speed of the wind turbine generator set is greater than the speed threshold. If so, execute step 6); otherwise, jump back to step 1); 6) Determine whether the wind speed of the wind turbine generator set is greater than the wind speed threshold. If so, the extreme wind shear flag is set to true, timer 2 starts timing, and step 7) is executed. Otherwise, jump back to step 1); 7) An additional pitch angle is superimposed on the output of the pitch PID controller of the wind turbine, and it is determined whether timer 2 is greater than the maximum time threshold of the strategic action. If so, no additional pitch action is superimposed, the extreme wind shear flag is reset to false, and timer 2 is cleared. Otherwise, an additional pitch angle is superimposed on the output of the pitch PID controller again.

2. The control method for reducing wind turbine load under extreme wind shear conditions according to claim 1, characterized in that: In step 1), the load sensor is installed in the front-to-rear direction of the yaw bearing of the wind turbine or on the top tower of the wind turbine. If the load sensor is installed in the front-to-rear direction of the yaw bearing, the front-to-rear load of the yaw bearing can be directly obtained for use. If the load sensor is installed on the top tower, it needs to be installed in the front-to-rear direction and left-to-right direction of the tower top respectively, and the front-to-rear load and side load of the tower top are obtained at the same time, and then converted into the front-to-rear load of the yaw bearing by the formula. The formula is as follows: My yawbearing =Mz towertop *cosγ+My towertop *sinγ In the formula, My yawbearing is the front and rear load of the yaw bearing, Mz towertop is the front and rear loads on the tower top, My towertop is the lateral load on the tower top, and γ is the angle of the wind turbine to the north.

3. The control method for reducing wind turbine load under extreme wind shear conditions according to claim 2, characterized in that: In step 1), after obtaining the front and rear loads of the yaw bearing, the load value needs to be filtered, including low-pass filtering and notch processing for the 3P frequency.

4. The control method for reducing wind turbine load under extreme wind shear conditions according to claim 3, characterized in that: In step 3), the yaw bearing front and rear load change rate is calculated using the load measurement values ​​at the current moment and the previous moment.

5. The control method for reducing the load of a wind turbine generator set under extreme wind shear conditions according to claim 4, characterized in that: In step 4), the pitch angle sensor information of the wind turbine is read, the pitch angles of all blades of the wind turbine are obtained and averaged, and then it is determined whether the average is greater than a pitch angle threshold.

6. The control method for reducing the load of a wind turbine generator set under extreme wind shear conditions according to claim 5, characterized in that: In step 5), the generator speed slip ring sensor information of the wind turbine is read. In order to obtain smoother speed information and prevent misjudgment caused by speed jumps, the sensor signal is filtered, including low-pass filtering and notching at multiple frequency points, and then it is determined whether the generator speed after filtering is greater than the speed threshold.

7. The control method for reducing wind turbine load under extreme wind shear conditions according to claim 6, characterized in that: In step 6), the wind speed sensor information of the wind turbine is read, an average value of multiple wind speed sensors is obtained, and then it is determined whether the average value is greater than a wind speed threshold.

8. The control method for reducing wind turbine load under extreme wind shear conditions according to claim 7, characterized in that: In step 7), the wind turbine can be retracted more quickly by superimposing an additional pitch angle, wherein the additional pitch angle is a unified retracting action or an independent retracting instruction for each blade based on the azimuth angle of the impeller.

9. A control system for reducing wind turbine load under extreme wind shear conditions, characterized in that: A control method for reducing the load of a wind turbine generator set under extreme wind shear conditions according to any one of claims 1 to 8, comprising: The load acquisition and filtering module is used to read the load sensor information, obtain the front and rear loads of the yaw bearing of the wind turbine and perform filtering processing; A first judgment module is used to judge whether the filtered load value is greater than the first load threshold. If so, the second judgment module is executed, otherwise the process jumps back to the load acquisition and filtering module; The second judgment module is used to judge whether the change rate of the front and rear load of the yaw bearing is greater than the first change rate threshold. If so, timer 1 starts timing. When the duration exceeds the first time threshold, it is judged whether the change rate of the front and rear load of the yaw bearing during the period is greater than the second change rate threshold. If so, the third judgment module is executed. If not, timer 1 is reset to zero and the process returns to the load acquisition and filtering module; wherein the second threshold is greater than the first threshold; A third judgment module is used to judge whether the pitch angle of the wind turbine is greater than the pitch angle threshold. If so, the fourth judgment module is executed, otherwise the load acquisition and filtering module is jumped back to; A fourth judgment module is used to judge whether the generator speed of the wind turbine is greater than a speed threshold. If so, the fifth judgment module is executed; otherwise, the load acquisition and filtering module is jumped back to; The fifth judgment module is used to determine whether the wind speed of the wind turbine is greater than the wind speed threshold. If so, the extreme wind shear flag is set to true, timer 2 starts timing, and the load reduction control module is executed. Otherwise, the module jumps back to the load acquisition and filtering module. The load reduction control module is used to superimpose an additional pitch angle on the output of the wind turbine pitch PID controller, and determine whether timer 2 is greater than the maximum time threshold of the strategy action. If so, no additional pitch action is superimposed, the extreme wind shear flag is reset to false, and timer 2 is cleared. Otherwise, an additional pitch angle is superimposed on the output of the pitch PID controller again.

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