Tower bottom limit load reduction method and device based on blade pre-variable pitch automatic optimization

Abstract

The invention provides a tower bottom limit load reduction method based on blade pre-variable pitch automatic optimization. The method comprises the steps that an initial variable pitch power interval and an initial pre-variable pitch angle are set; calculating a plurality of tower bottom combined bending moment loads under different wind speeds under the working condition of DLC1.3, and respectively drawing a power-load scatter diagram and a power-load envelope curve diagram according to the maximum load value of the tower bottom combined bending moment and the power of the wind turbine generator when the load value appears; after the pre-variable pitch angle is adjusted, the multiple tower bottom combined bending moment loads under the DLC1.3 working condition and different wind speeds are calculated again, and the maximum value in the multiple tower bottom combined bending moment loads is taken as the maximum tower bottom combined bending moment load value; the maximum load value of the tower bottom combined bending moment is compared with the target load of the tower bottom combined bending moment, and if the maximum load value is smaller than the target load value, calculation of tower bottom limit load reduction is completed. The blade pitch angle can be controlled to change along with the change of power, so that the aerodynamic force borne by the wind wheel is reduced, the tower bottom load is reduced, and the purpose of reducing the tower bottom limit load is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine tower load assessment, and in particular to a method and device for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation. Background Art

[0002] In the era of wind power parity, it is necessary to ensure high power generation and low investment costs, and more importantly, to ensure the reliability of the unit. In pursuit of lower costs, longer impeller diameters, higher hub heights, and higher power wind turbines have become the main response to reduce costs, increase efficiency, and improve competitiveness. Especially for plain wind farms with low wind speeds, poor wind resources, but relatively high wind shear coefficients, and nonlinear increase in wind speed and height, increasing the tower height can effectively increase power generation, improve the level of wind energy utilization in large shear and low wind speed areas, and increase wind farm benefits.

[0003] The tower of a large wind turbine generator accounts for a large proportion of the total cost of the wind turbine generator set. The higher the tower, the greater the load, the heavier the tower, and the higher the cost of tower materials, transportation, and hoisting. Under the premise of ensuring the life and safety of the tower, how to better reduce the load of the high tower is the key to reducing the tower cost.

[0004] As the main load-bearing component of the unit, the tower needs to withstand a variety of loads, among which the aerodynamic force acting on the wind rotor at the top of the tower is the main source of tower load. For variable pitch wind turbines, the blade pitch angle can be controlled to reduce the wind receiving area of ​​the blades, reduce the aerodynamic force on the wind rotor, and thus reduce the tower load. Therefore, for large wind turbines, how to reduce the tower limit load by controlling the pitch angle has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention proposes a method and equipment for reducing the tower bottom extreme load based on automatic optimization of blade pre-pitch, sets the blade pre-pitch angle for the unit operating at rated power, and controls the blade pitch angle to change with the power when the unit operates below the rated power, so as to reduce the projected area of ​​the blade perpendicular to the incoming wind direction, thereby achieving the purpose of reducing the inferior load on the tower; the tower extreme load is reduced by changing the pre-pitch angle.

[0006] The technical solution adopted by the present invention is as follows:

[0007] In a first aspect, a method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation is provided, comprising the following steps:

[0008] According to the normal power generation condition of the wind turbine under extreme turbulent wind, the maximum load values ​​of multiple tower bottom moments under different wind speeds and the power of the wind turbine when the load value appears, the power-load scatter diagram and the power-load envelope curve diagram are drawn respectively;

[0009] According to the power-load scatter diagram and the power-load envelope curve diagram, the maximum value of all tower bottom combined bending moment loads is taken as the maximum tower bottom combined bending moment load value;

[0010] Compare the maximum load value of the tower bottom combined bending moment with the target load of the tower bottom combined bending moment. If the maximum load value is less than the target load value, complete the calculation of the tower bottom ultimate load reduction.

[0011] Furthermore, according to the maximum load value of the combined bending moment at the bottom of the tower and the power of the wind turbine when the load value occurs, a power-load scatter diagram and a power-load envelope curve diagram are drawn respectively, including:

[0012] Set the initial pitch power range and initial pre-pitch angle;

[0013] According to the initial pre-pitch angle, the multiple combined bending moment loads at the bottom of the tower under normal power generation conditions of the wind turbine under extreme turbulent wind and different wind speeds are calculated to obtain the maximum combined bending moment load value at the bottom of the first tower and the maximum combined bending moment load value at the bottom of the second tower;

[0014] Draw a power-load scatter plot based on the maximum load value of the combined bending moment at the bottom of the first tower and the power of the wind turbine when the load value occurs;

[0015] According to the maximum load value of the combined bending moment at the bottom of the second tower and the power of the wind turbine when this load value occurs, a power-load envelope curve is drawn.

[0016] Furthermore, the initial pitch power interval is evenly divided into 4-5 intervals according to the power generation level of the wind turbine generator set, and the initial pre-pitch angle is 0 degree.

[0017] Furthermore, the normal power generation condition of the wind turbine under extreme turbulent wind flow includes multiple seed conditions. For all calculated tower bottom moment loads:

[0018] The maximum load among the combined bending moment loads at the bottom of the tower in each type of seed working condition is taken as the maximum combined bending moment load value at the bottom of the first tower;

[0019] According to the IEC-61400 standard on the statistical rules and safety factors for the ultimate loads of normal power generation conditions under extreme turbulent wind, the maximum load among the combined bending moment loads at the bottom of the tower at each wind speed is calculated as the maximum combined bending moment load value at the bottom of the second tower.

[0020] Furthermore, according to the power-load scatter diagram and the power-load envelope curve diagram, the maximum value of all tower bottom moment loads is taken as the maximum tower bottom moment load value, including:

[0021] According to the power-load scatter diagram and the power-load envelope curve diagram, the parameter setting of the pre-pitch angle is adjusted to obtain the control pitch input angle;

[0022] According to the input angle of the pitch control, the wind turbine is recalculated under normal power generation conditions under extreme turbulent wind flow and multiple tower bottom moment loads under different wind speeds;

[0023] The maximum value of all the tower bottom combined bending moment loads is taken as the maximum tower bottom combined bending moment load value.

[0024] Further, the parameter setting of the pre-pitch angle is adjusted according to the power-load scatter diagram and the power-load envelope curve diagram to obtain the controlled pitch input angle; including:

[0025] According to the power-load scatter diagram and the power-load envelope curve diagram, the difference between the first and second maximum load values ​​of the tower bottom combined bending moment in each power interval and the target load value of the tower bottom combined bending moment is compared. According to the negative correlation between the increase or decrease of load and the increase or decrease of the pre-pitch angle, the parameter setting of the blade pre-pitch angle in each power interval is adjusted, and the parameter is used as the input angle for the next round of pitch control.

[0026] Further, the parameter setting of the blade pre-pitch angle in each power range is adjusted. When the adjustment is made for the first time, the blade pre-pitch angle adjustment amplitude is +2°;

[0027] When making adjustments in the subsequent iterative calculation process, the angle adjustment amplitude is adjusted according to the comparison of the first two rounds of load data and the changes in the blade pre-pitch; the input angle of the control pitch cannot be negative, and the pre-pitch angle of the next power point is not less than the pre-pitch angle of the previous power point.

[0028] Furthermore, the method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation also includes:

[0029] If the maximum load value is greater than or equal to the target load value, obtain the maximum load value of the first tower bottom combined bending moment and the maximum load value of the second tower bottom combined bending moment in a new round, draw a new round of power-load scatter diagram and power-load envelope curve diagram, compare the difference between the first and second tower bottom combined bending moment maximum load values ​​and the target load value in each power interval, adjust the blade pre-pitch angle parameter setting in each power interval according to the difference, and use it as the control pitch input angle for a new round of iterative calculation until the maximum value of the tower bottom combined bending moment load is less than the target load value.

[0030] In a second aspect, an electronic device is provided, including:

[0031] one or more processors;

[0032] A storage device for storing one or more programs;

[0033] When one or a program is executed by one or more processors, the one or more processors implement the tower bottom limit load reduction method based on automatic optimization of blade pre-pitch variation as described in the first aspect.

[0034] In a third aspect, a computer program product is also provided, including a computer program / instruction, which, when executed by a processor, implements the steps of the method for reducing the tower bottom extreme load based on automatic optimization of blade pre-pitch variation as described in the first aspect.

[0035] It can be seen from the above technical solution that the beneficial technical effects of the present invention are as follows:

[0036] 1. A blade pitch control strategy based on power control is adopted. By counting the combined bending moment load at the bottom of the tower under different powers of the wind turbine, the pre-pitch angle setting of the blades corresponding to different powers is automatically adjusted as the input of the next round of iterative control. The optimization is automatically iterated to control the blade pitch angle to change with the change of power, so as to reduce the aerodynamic force on the wind wheel, thereby reducing the load at the bottom of the tower and achieving the purpose of reducing the ultimate load at the bottom of the tower.

[0037] 2. When used in on-site production, the entire process control parameters can be automatically adjusted and automatically iterated to find the best result. The results are accurate and reliable, greatly improving the efficiency and accuracy of load shedding. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0039] Figure 1 A schematic diagram of a method flow of an embodiment of the present invention;

[0040] Figure 2 A power-load scatter diagram of an embodiment of the present invention;

[0041] Figure 3 4 is a power-envelope curve diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0043] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0044] Example

[0045] When a variable speed and variable pitch wind turbine is operating below the rated wind speed, in order to ensure that the wind turbine captures as much wind energy as possible, the optimal pitch angle is usually kept unchanged, and the maximum power tracking method (MPPT) is adopted. The electromagnetic torque of the generator is adjusted by the converter to make the wind rotor speed follow the wind speed change, so that the wind energy utilization coefficient is kept at the maximum, and the wind turbine is always running at the maximum power point. However, during this period, since the blades are kept at the optimal pitch angle, the projected area of ​​the blades perpendicular to the incoming wind direction is the largest, which will cause the flapping load component in the blade root load to account for a large proportion, and at the same time, the overturning moment load contributed to the bottom of the tower is large, which in turn leads to a large combined bending moment load at the bottom of the tower. The dominant operating condition is the normal power generation condition under extreme turbulent incoming wind, that is, the DLC1.3 condition.

[0046] This embodiment provides a method for reducing the extreme load at the bottom of the tower based on automatic optimization of blade pre-pitch, setting the pre-pitch angle for the unit to operate at rated power, and controlling the blade pitch angle to change with the power when the unit is operating below rated power, so as to reduce the projected area of ​​the blade perpendicular to the incoming wind direction, thereby achieving the purpose of reducing the tower load. Specifically, the following steps are included:

[0047] S1. Set the initial pitch power range and initial pre-pitch angle

[0048] The initial pitch power interval is set according to the full power of the wind turbine. In a specific implementation, it is evenly divided into 4-5 intervals according to the power level. For example, for a 5WM unit, the initial pitch power interval point is set to [0 1000 2000 3000 4000 5000], and the initial pre-pitch angle corresponding to each power interval is 0 degrees, that is, the pre-pitch initial angle is [0 0 0 0 00].

[0049] S2. According to the initial pre-pitch angle, calculate the multiple tower bottom moment loads under DLC1.3 working condition and different wind speeds. According to the IEC-61400 standard on the statistical rules and safety factors of the limit loads of DLC1.3 working condition, obtain the maximum load value of the first tower bottom moment and the maximum load value of the second tower bottom moment under DLC1.3 working condition, and set the tower bottom moment target load value at the same time.

[0050] Specifically, the DLC1.3 working condition includes multiple seed working conditions; for all calculated tower bottom combined bending moment loads, the maximum value of the tower bottom combined bending moment load of each type of seed working condition of the DLC1.3 working condition is used as the first tower bottom combined bending moment maximum load value; there are multiple first tower bottom combined bending moment maximum load values, which correspond to each type of seed working condition.

[0051] According to the IEC-61400 standard on the statistical rules and safety factors of the ultimate loads of the DLC1.3 working condition, the maximum load in the tower bottom combined bending moment load under the DLC1.3 working condition at each wind speed is calculated as the maximum load value of the second tower bottom combined bending moment; there are multiple maximum load values ​​of the second tower bottom combined bending moment, corresponding to each wind speed respectively.

[0052] At the same wind speed, the maximum load value of the combined bending moment at the bottom of the first tower and the maximum load value of the combined bending moment at the bottom of the second tower may be the same or may be different.

[0053] At the same time, in this step, the tower bottom combined bending moment target load value is set for use in subsequent steps.

[0054] S3. Draw a power-load scatter plot based on the maximum load value of the combined bending moment at the bottom of the first tower and the power of the wind turbine when this load value occurs.

[0055] With the maximum load value of the combined bending moment at the bottom of the first tower as the ordinate and the power of the wind turbine when this load value appears as the abscissa, a power-load scatter plot is drawn, as shown in Figure 2 The scatter plots are shown.

[0056] S4. Draw a power-load envelope curve according to the maximum load value of the combined bending moment at the bottom of the second tower and the power of the wind turbine when this load value occurs.

[0057] The maximum load value of the combined bending moment at the bottom of the second tower is taken as the ordinate, and the power of the wind turbine when this load value appears is taken as the abscissa. According to the envelope value method of the load at different powers, the power-load envelope curve is drawn, as shown in the figure. Figure 3 The Baoluo curve is shown.

[0058] In a specific implementation, steps S3 and S4 are performed in any order.

[0059] S5. Adjust the parameter setting of the pre-pitch angle according to the power-load scatter diagram and the power-load envelope curve diagram to obtain the control pitch input angle.

[0060] According to the power-load scatter plot and the power-load envelope curve, the difference between the first and second maximum load values ​​of the tower bottom moment in each power interval and the target load value of the tower bottom moment set in step S2 is compared, and the parameter setting of the blade pre-pitch angle in each power interval is adjusted according to the negative correlation between the load increase and decrease and the pre-pitch angle increase and decrease, and the parameter is used as the input angle of the next round of control pitch. There can be multiple input angles for controlling pitch, and each power point corresponds to one input angle.

[0061] In some embodiments, the parameter settings of the blade pre-pitch angle in each power interval are adjusted according to the initial pre-pitch calculation load result. When the adjustment is made for the first time, the blade pre-pitch angle adjustment amplitude is +2°. For example, for a 5MW unit, the initial power interval is [0 1000 2000 3000 4000 5000], the initial pre-pitch angle is [0 0 0 0 0 0]. According to the initial pre-pitch calculation power-load scatter diagram and the power-load envelope curve, it is judged that the combined bending moment load value in the power interval [3000 4000 5000] is greater than the target value. Then the pre-pitch parameter of the power point in this interval is +2°, that is, the power interval is [0 1000 2000 300040005000] and the corresponding new pre-pitch angle is [0 0 0 0 2 2]. If the load reduction requirements are not met in the first calculation process of the subsequent steps, the angle adjustment amplitude will be adjusted in the subsequent iterative calculation process according to the comparison of the previous two rounds of load data and the changes in the blade pre-pitch. For example, the new pre-pitch angle [0 0 0 0 22] calculates that the tower moment load decreases by 5% in the power range [4000 5000], and this range is still greater than the target load by 3%. Then the new round of pre-pitch angle can be adjusted to [0 0 0 0 2 3.2]. At the same time, the angle adjustment amplitude strategy must meet the following requirements: the input angle of the pitch cannot be negative, and the power range cannot be non-increasing, that is, the pre-pitch angle of the next power point is not less than the pre-pitch angle of the previous power point.

[0062] S6. According to the input angle of the control pitch, recalculate the multiple tower bottom moment loads under DLC1.3 working condition and different wind speeds, and take the maximum value of all the multiple tower bottom moment loads as the maximum tower bottom moment load value.

[0063] The method for calculating the combined bending moment load at the tower bottom in this step is the same as that in step S2, except that this step does not use the initial pre-pitch angle, but the input angle of the controlled pitch obtained in step S5. After calculation, the maximum combined bending moment load value at the tower bottom obtained by data statistics is only 1.

[0064] S7. Compare the maximum load value of the combined bending moment at the bottom of the tower with the target load of the combined bending moment at the bottom of the tower. If the maximum load value is less than the target load value, the load reduction calculation of the ultimate load at the bottom of the tower is completed.

[0065] The maximum load value of the tower bottom combined bending moment obtained in step S6 is compared with the set tower bottom combined bending moment target load value. If the maximum load value is less than the target load value, the calculation is terminated and the tower bottom combined bending moment load result is output at the same time. The control pitch input angle obtained in step S5 is used as the final control input parameter to achieve the goal of reducing the tower limit load.

[0066] If the maximum load value is greater than or equal to the target load value, repeat steps S2-S7. Specifically, according to the multiple tower bottom moment loads obtained in step S6, obtain the first tower bottom moment maximum load value and the second tower bottom moment maximum load value of a new round according to step S2, draw a new round of power-load scatter plots and power-load envelope curves, compare the first and second tower bottom moment maximum load values ​​of each power interval with the target load value, adjust the blade pre-pitch angle parameter settings of each power interval according to the difference, and use it as the new round of control pitch input angle, iteratively calculate until the maximum value of the tower bottom moment load is less than the target load value, output the tower bottom moment load result that meets the target, and complete the automatic iterative optimization load reduction.

[0067] In some embodiments, an electronic device is also provided, including:

[0068] one or more processors;

[0069] A storage device for storing one or more programs;

[0070] When one or more programs are executed by one or more processors, the one or more processors implement the tower bottom limit load reduction method based on automatic optimization of blade pre-pitch variation as described above.

[0071] In some embodiments, a computer program product is also provided, including a computer program / instruction, which, when executed by a processor, implements the steps of the tower bottom extreme load reduction method based on automatic optimization of blade pre-pitch variation as described above.

[0072] The technical solution of this embodiment adopts a blade pitch control strategy based on a power control method. By counting the combined bending moment load at the bottom of the tower under different powers of the wind turbine, the blade pre-pitch angle settings corresponding to different powers are automatically adjusted and used as the input for the next round of iterative control. The optimization is automatically iterated to control the blade pitch angle to change with the change of power, so as to reduce the aerodynamic force on the wind wheel, thereby reducing the load at the bottom of the tower and achieving the purpose of reducing the ultimate load at the bottom of the tower.

[0073] When the technical solution of this embodiment is used in on-site production, it can realize automatic adjustment and automatic iterative optimization of the control parameters of the entire process, and the results are accurate and reliable, which greatly improves the load shedding efficiency and accuracy.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation, characterized in that: The following steps are involved: According to the normal power generation condition of the wind turbine under extreme turbulent wind, the maximum load values ​​of multiple tower bottom moments under different wind speeds and the power of the wind turbine when the load value appears, the power-load scatter diagram and the power-load envelope curve diagram are drawn respectively; According to the power-load scatter diagram and the power-load envelope curve diagram, the maximum value of all tower bottom combined bending moment loads is taken as the maximum tower bottom combined bending moment load value; Compare the maximum load value of the tower bottom combined bending moment with the target load of the tower bottom combined bending moment. If the maximum load value is less than the target load value, complete the calculation of the tower bottom ultimate load reduction.

2. The method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation according to claim 1 is characterized in that: According to the maximum load value of the combined bending moment at the bottom of the tower and the power of the wind turbine when this load value occurs, a power-load scatter diagram and a power-load envelope curve diagram are drawn respectively, including: Set the initial pitch power range and initial pre-pitch angle; According to the initial pre-pitch angle, the multiple combined bending moment loads at the bottom of the tower under normal power generation conditions of the wind turbine under extreme turbulent wind and different wind speeds are calculated to obtain the maximum combined bending moment load value at the bottom of the first tower and the maximum combined bending moment load value at the bottom of the second tower; Draw a power-load scatter plot based on the maximum load value of the combined bending moment at the bottom of the first tower and the power of the wind turbine when the load value occurs; According to the maximum load value of the combined bending moment at the bottom of the second tower and the power of the wind turbine when this load value occurs, a power-load envelope curve is drawn.

3. The method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation according to claim 2 is characterized in that: The initial pitch power interval is evenly divided into 4-5 intervals according to the power generation level of the wind turbine generator set, and the initial pre-pitch angle is 0 degree.

4. The method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation according to claim 2 is characterized in that: The normal power generation conditions of wind turbines under extreme turbulent wind flow include multiple seed conditions. For all calculated tower bottom moment loads: The maximum load among the combined bending moment loads at the bottom of the tower in each type of seed working condition is taken as the maximum combined bending moment load value at the bottom of the first tower; According to the IEC-61400 standard on the statistical rules and safety factors for the ultimate loads of normal power generation conditions under extreme turbulent wind, the maximum load among the combined bending moment loads at the bottom of the tower at each wind speed is calculated as the maximum combined bending moment load value at the bottom of the second tower.

5. The method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation according to claim 1 is characterized in that: According to the power-load scatter diagram and the power-load envelope curve diagram, the maximum value of all tower bottom moment loads is taken as the maximum tower bottom moment load value, including: According to the power-load scatter diagram and the power-load envelope curve diagram, the parameter setting of the pre-pitch angle is adjusted to obtain the control pitch input angle; According to the input angle of the pitch control, the wind turbine is recalculated under normal power generation conditions under extreme turbulent wind flow and multiple tower bottom moment loads under different wind speeds; The maximum value of all the tower bottom combined bending moment loads is taken as the maximum tower bottom combined bending moment load value.

6. The method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation according to claim 5 is characterized in that: According to the power-load scatter diagram and the power-load envelope curve diagram, the parameter setting of the pre-pitch angle is adjusted to obtain the control pitch input angle; including: According to the power-load scatter diagram and the power-load envelope curve diagram, the difference between the first and second maximum load values ​​of the tower bottom combined bending moment in each power interval and the target load value of the tower bottom combined bending moment is compared. According to the negative correlation between the increase or decrease of load and the increase or decrease of the pre-pitch angle, the parameter setting of the blade pre-pitch angle in each power interval is adjusted, and the parameter is used as the input angle for the next round of pitch control.

7. The method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation according to claim 6 is characterized in that: Adjust the parameter settings of the blade pre-pitch angle in each power range. When adjusting for the first time, the blade pre-pitch angle adjustment amplitude is +2°; When making adjustments in the subsequent iterative calculation process, the angle adjustment amplitude is adjusted according to the comparison of the first two rounds of load data and the changes in the blade pre-pitch; the input angle of the control pitch cannot be negative, and the pre-pitch angle of the next power point is not less than the pre-pitch angle of the previous power point.

8. The method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation according to claim 2 is characterized in that: Also includes: If the maximum load value is greater than or equal to the target load value, obtain the maximum load value of the first tower bottom combined bending moment and the maximum load value of the second tower bottom combined bending moment in a new round, draw a new round of power-load scatter diagram and power-load envelope curve diagram, compare the difference between the first and second tower bottom combined bending moment maximum load values ​​and the target load value in each power interval, adjust the blade pre-pitch angle parameter setting in each power interval according to the difference, and use it as the control pitch input angle for a new round of iterative calculation until the maximum value of the tower bottom combined bending moment load is less than the target load value.

9. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the tower bottom extreme load reduction method based on automatic optimization of blade pre-pitch variation as described in any one of claims 1-8.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by the processor, the steps of the method for reducing the tower bottom limit load based on automatic optimization of blade pre-pitch variation as described in any one of claims 1 to 8 are implemented.

Images