A wind turbine blade root load reduction control method and system

Abstract

The application discloses a wind turbine blade root load reduction control method and system. The method comprises the following steps: configuring a load sensor at each blade root of a wind turbine, obtaining the load in the flapwise and edgewise directions of each blade root of the wind turbine, performing data processing and analysis on the measured load, converting the measured load into the blade root load in the root coordinate system, and then converting the blade root load into the blade root load in the rotating hub coordinate system through coordinate conversion. The obtained blade root load is subjected to preset logical judgment to execute a control action, that is, an additional nonlinear pitch command is applied, so as to reduce the blade root load of the wind turbine. The application configures a blade root load sensor, performs data processing and analysis on the measured load, and applies an additional pitch command, so as to reduce the blade root load of the wind turbine, improve the safety of the wind turbine, reduce the manufacturing cost of the wind turbine, and solve the problem of excessive blade root load of the wind turbine when the wind turbine operates in the rated section, especially when the wind turbine encounters an extreme wind shear working condition.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind turbine load reduction control, in particular to a wind turbine blade root load reduction control method and system. BACKGROUND

[0002] With the continuous increase of single capacity of wind turbine, the length, weight and swept area of the turbine blade are also increasing. The control of the limit load of the turbine limits the development of large-scale turbine and tests the safety and economy of the turbine.

[0003] Extreme wind shear condition is an extreme condition, which is characterized by superimposing extreme wind shear on the basis of vertical wind shear. When the wind turbine operates in the rated section and encounters this condition, the blade root load increases sharply. If it exceeds the bearing capacity of the blade, it will cause the blade to break and other adverse consequences.

[0004] At present, there are few methods for controlling blade root load under extreme wind shear. The conventional wind measurement device is volatile and unreliable, and the laser radar wind measurement is difficult to identify horizontal wind shear, and the cost of laser radar system is high. Therefore, there is an urgent need for a low-cost and efficient blade root load control method for extreme wind shear condition. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provides a wind turbine blade root load reduction control method and system, which solves the problem of excessive blade root load when the wind turbine operates in the rated section, especially when it encounters extreme wind shear condition. By configuring a blade root load sensor, the measured load is processed and analyzed, and an additional pitch command is applied to reduce the blade root load of the turbine and improve the safety of the wind turbine.

[0006] The purpose of the present application is achieved by the following technical solution: a wind turbine blade root load reduction control method, which comprises configuring a load sensor at each blade root of the wind turbine, obtaining the load in the pitch and flap directions of each blade root of the wind turbine, processing and analyzing the measured load, calibrating the measured load to the blade root load in the root coordinate system, and then converting it to the blade root load in the rotating hub coordinate system. The obtained blade root load is subjected to a preset logical judgment to execute a control action, i.e. an additional nonlinear pitch command is applied to reduce the blade root load of the wind turbine.

[0007] Further, the method comprises the following steps:

[0008] S1, configuring a blade root load sensor system;

[0009] S2, according to the blade root load sensor system and the measurement system built in the wind turbine, collect the wind turbine blade root load calibration and other variable values of the wind turbine;

[0010] S3, perform coordinate system transformation processing on the wind turbine blade root load calibration, and perform filtering processing on the other variable values of the wind turbine;

[0011] S4, read the processed wind turbine blade root load and other variable values of the wind turbine;

[0012] S5, according to the wind turbine blade root load and other variable values of the wind turbine read in step S4, judge whether the wind turbine is in normal power generation mode, if the wind turbine is judged to be in normal power generation mode, execute step S6, if the wind turbine is judged not to be in normal power generation mode, return to step S4;

[0013] S6, according to the wind turbine blade root load and other variable values of the wind turbine read in step S4, judge whether the blade root load control flag is set to True, if the blade root load control flag is True, execute step S7, if the blade root load control flag is not True, return to step S4;

[0014] S7, superimpose an additional pitch command Δθ on each blade of the wind turbine, and set a timer 1 to start timing at the same time, execute step S8;

[0015] S8, according to the wind turbine blade root load and other variable values of the wind turbine read in step S4, judge whether the blade root load control flag is set to False, if the blade root load control flag is False, return to step S4 at the same time, complete the reduction of the wind turbine blade root load, if the blade root load control flag is not False, return to step S4.

[0016] Further, the step S1 comprises the following steps:

[0017] Load sensors are arranged in the edgewise and flapping directions of each blade root section of the wind turbine to form a blade root load sensor system to obtain blade root Mx and My load calibration.

[0018] Further, the step S2 comprises the following steps:

[0019] According to the blade root load sensor system and the measurement system built in the wind turbine, collect the wind turbine blade root Mx and My load calibration and the wind speed, rotational speed and pitch angle values of the wind turbine; wherein the measurement system built in the wind turbine includes an anemometer, a pitch angle measuring instrument, a rotational speed slip ring sensor and a storage control module unit.

[0020] Further, in step S3, the other variable values of the wind turbine are filtered, including the following steps:

[0021] The wind speed, rotational speed and pitch angle values of the wind turbine are filtered, and the filtered variable values are sent to the storage control module unit of the wind turbine; wherein the wind speed filter is a sliding average filter, the rotational speed filter is a second-order low-pass filter, and the pitch angle filter is a second-order notch filter.

[0022] Further, in step S3, the wind turbine blade root load calibration is processed by coordinate system transformation, including the following steps:

[0023] The blade root Mx and My loads in the root coordinate system are converted into the blade root Mx and My loads in the rotating hub coordinate system, and the formula is as follows:

[0024] Mx RhubBladeRoot = Mx RootBladeRoot cos θ + My RootBladeRoot sin θ

[0025] My RhubBladeRoot = Mx RootBladeRoot sin θ + My RootBladeRoot cos θ

[0026] Wherein, Mx RhubBladeRoot , My RhubBladeRoot are the blade root Mx and My loads in the rotating hub coordinate system, Mx RootBladeRoot , My RootBladeRoot are the blade root Mx and My loads in the root coordinate system, and θ is the blade pitch angle.

[0027] Finally, the blade root Mx and My loads in the rotating hub coordinate system are converted into the bending moment Mxy and filtered.

[0028] Further, the step S5 includes the following steps:

[0029] Determine whether the measured pitch angle is greater than the preset pitch angle threshold θ0, the filtered wind speed is greater than the preset wind speed threshold W0, and the measured rotational speed exceeds the rated rotational speed Ω0, if so, determine that the wind turbine is in normal power generation mode, execute step S6, if not, return to step S4.

[0030] Further, the step S6 includes the following steps:

[0031] If the maximum value of the combined bending moment Mxy is greater than the preset threshold S1, the maximum deviation value of the My load is greater than the preset deviation threshold S2, and the differential value of the combined bending moment Mxy is greater than the preset differential threshold S3 for a time T0, the blade root load control flag is set to True, step S7 is executed, and if not, the process returns to step S4.

[0032] Further, the step S8 includes the following steps:

[0033] If the maximum value of the combined bending moment Mxy is less than the preset threshold S1 or the timer 1 exceeds a given time, the blade root load control flag is set to False, and the timer 1 is reset to zero, completing the reduction of the blade root load of the wind turbine, and if not, the process returns to step S4.

[0034] A wind turbine blade root load reduction control system for implementing the wind turbine blade root load reduction control method described above, the system comprising a blade root load sensor system, a wind speed meter, a pitch angle measuring instrument, a rotating speed slip ring sensor, and a programmable storage control module unit, wherein the wind speed meter, the pitch angle measuring instrument, the rotating speed slip ring sensor, and the programmable storage control module unit are all built into the wind turbine, and the blade root load sensor system comprises a plurality of load sensors arranged in the flapwise and edgewise directions at each blade root section of the wind turbine.

[0035] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0036] The present application only requires an additional set of load sensor system, which is low in cost; at the same time, the judgment algorithm used is simple, direct, and efficient, which can effectively control the limit load of the wind turbine, especially the limit load of the blade root under extreme wind shear, improve the safety of the unit, and reduce the design cost of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flowchart of the wind turbine blade root load reduction control method of the present application.

[0038] Figure 2 The load reduction control effect line graph of the present application. DETAILED DESCRIPTION

[0039] The present application will be further described below in conjunction with specific examples.

[0040] Example 1

[0041] Referring to Figure 1 The wind turbine blade root load reduction control method provided by the present embodiment includes the following steps:

[0042] S1, set up load sensors in each blade root section of the wind turbine in the edgewise and flapwise directions to form a blade root load sensor system to obtain blade root Mx and My load calibration;

[0043] S2, according to the blade root load sensor system and the built-in measurement system of the wind turbine, collect the wind speed, rotational speed, and pitch angle values of the wind turbine, as well as the blade root Mx and My load calibration; wherein the built-in measurement system of the wind turbine includes an anemometer, a pitch angle measuring instrument, a rotational speed slip ring sensor, and a storage control module unit;

[0044] S3, filter the collected wind speed, rotational speed, and pitch angle values of the wind turbine, and send the filtered variable values to the storage control module unit of the wind turbine; wherein the wind speed filter is a sliding average filter, the rotational speed filter is a second-order low-pass filter, and the pitch angle filter is a second-order notch filter;

[0045] convert the blade root Mx and My loads in the root coordinate system into blade root Mx and My loads in the rotating hub coordinate system, with the formulas as follows:

[0046] Mx RhubBladeRoot =Mx RootBladeRoot ·cosθ+My RootBladeRoot ·sinθ

[0047] My RhubBladeRoot =Mx RootBladeRoot ·sinθ+My RootBladeRoot ·cosθ;

[0048] wherein Mx RhubBladeRoot , My RhubBladeRoot are the blade root Mx and My loads in the rotating hub coordinate system, Mx RootBladeRoot , My RootBladeRoot are the blade root Mx and My loads in the root coordinate system, and θ is the blade pitch angle;

[0049] Finally, convert the blade root Mx and My loads in the rotating hub coordinate system into the combined bending moment Mxy and perform filtering.

[0050] S4, read the processed wind turbine blade root load and other variable values of the wind turbine;

[0051] S5, judging whether the measured pitch angle is greater than a preset pitch angle threshold θ0, the filtered wind speed is greater than a preset wind speed threshold W0, and the measured rotating speed exceeds a rated rotating speed Ω0 are satisfied simultaneously, if yes, judging that the wind turbine is in a normal power generation mode, executing step S6, if no, returning to step S4; taking a 5 MW wind turbine example model as an example, the preset pitch angle threshold θ0 is 0.5 deg, the wind speed threshold W0 is 10 m / s, and the rated rotating speed Ω0 is 1200 rpm;

[0052] S6, judging whether the maximum value of the combined bending moment Mxy is greater than a preset threshold S1, the maximum deviation value of the My load is greater than a preset deviation threshold S2, and the differential value of the combined bending moment Mxy continuously exceeds a preset differential threshold S3 within a time T0 are satisfied simultaneously, if yes, setting a blade root load control flag bit to True, executing step S7, if no, returning to step S4; the thresholds corresponding to different models need to be adjusted according to the load values of the models, taking the 5 MW wind turbine example model as an example, the preset threshold S1 is 10000 kNm, the threshold is 5000 kNm, T0 is 1.0 s, and the threshold S3 is 2000 kNm;

[0053] S7, superimposing an additional pitch-in command Δθ on each blade of the wind turbine, simultaneously setting a timer 1 to start timing, and executing step S8; taking the 5 MW wind turbine example model as an example, the additional pitch-in command Δθ is 1.5 deg / s;

[0054] S8, judging whether the maximum value of the combined bending moment Mxy is less than the preset threshold S1 or the timer 1 exceeds a given time, if yes, setting the blade root load control flag bit to False, simultaneously resetting the timer 1 to zero, completing the reduction of the blade root load of the wind turbine, if no, returning to step S4; taking the 5 MW wind turbine example model as an example, the preset threshold S1 is 10000 kNm, and the maximum given time of the timer 1 is 1 s.

[0055] Referring to Figure 2 shown, it can be seen that, after the experimental group executes the additional pitch-in action through the judgment condition, the blade root load is effectively prevented from continuing to increase, and the blade root limit load of the wind turbine is reduced.

[0056] Embodiment 2

[0057] The embodiment discloses a wind turbine blade root load reduction control system for implementing the wind turbine blade root load reduction control method in embodiment 1, the system comprising a blade root load sensor system, a wind speed meter, a pitch angle measuring instrument, a rotating speed slip ring sensor and a programmable storage control module unit, wherein the wind speed meter, the pitch angle measuring instrument, the rotating speed slip ring sensor and the programmable storage control module unit are all built in the wind turbine, and the blade root load sensor system comprises a plurality of load sensors arranged in the flapwise and edgewise directions of each blade root section of the wind turbine.

[0058] Embodiment 3

[0059] The embodiment discloses a non-transitory computer readable medium storing instructions, when the instructions are executed by a processor, steps of the wind turbine blade root load reduction control method according to embodiment 1 are executed.

[0060] The non-transitory computer readable 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.

[0061] Embodiment 4

[0062] The embodiment discloses a computing device comprising a processor and a memory for storing a processor-executable program, when the processor executes the program stored in the memory, the wind turbine blade root load reduction control method according to embodiment 1 is implemented.

[0063] 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 processor functions.

[0064] The above-mentioned embodiments are only the preferred embodiments of the present application, and do not limit the scope of the present application, so that any changes made according to the shape and principle of the present application should be covered in the protection scope of the present application.

Claims

1. A method for controlling blade root load reduction of a wind turbine, characterized by: The method is to configure load sensors at the roots of each blade of the wind turbine to obtain the loads in the swing and flapping directions of each blade root of the wind turbine, perform data processing and analysis on the measured loads, convert the measured load calibration into the blade root load in the root coordinate system, and then convert the coordinates into the blade root load in the rotating hub coordinate system. The obtained blade root load is subjected to preset logical judgment to execute a control action, that is, to apply additional nonlinear blade retraction instructions, thereby reducing the blade root load of the wind turbine. The method comprises the following steps: S1. Configure blade root load sensor system; S2. Collecting the wind turbine blade root load calibration and the wind speed, rotation speed and pitch angle values ​​of the wind turbine according to the blade root load sensor system and the built-in measurement system of the wind turbine; S3, performing coordinate system transformation on the blade root load calibration of the wind turbine generator set, and filtering the wind speed, rotation speed and pitch angle value of the wind turbine generator set; The process of performing coordinate system transformation on the wind turbine blade root load calibration includes the following steps: The blade root Mx and My loads in the root coordinate system are converted to the blade root Mx and My loads in the rotating hub coordinate system. The formula is as follows: Mx RhubBladeRoot =Mx RootBladeRoot ·cosθ+My RootBladeRoot ·sinθ My RhubBladeRoot =Mx RootBladeRoot ·sinθ+My RootBladeRoot ·cosθ; Among them, Mx RhubBladeRoot 、My RhubBladeRoot Mx and My are the blade root loads in the rotating hub coordinate system, Mx RootBladeRoot 、My RootBladeRoot are the blade root Mx and My loads in the root coordinate system, respectively, and θ is the blade pitch angle; Finally, the blade root loads Mx and My in the rotating hub coordinate system are converted into the combined bending moment Mxy and filtered; S4, reading the processed wind turbine blade root load and the wind speed, rotation speed and pitch angle value of the wind turbine; S5. Determine whether the wind turbine is in a normal power generation mode based on the wind turbine blade root load and the wind speed, rotation speed, and pitch angle values ​​of the wind turbine read in step S4. If the wind turbine is in a normal power generation mode, execute step S6. If the wind turbine is not in a normal power generation mode, return to step S4. S6. Based on the wind turbine blade root load and the wind speed, rotation speed, and pitch angle values ​​of the wind turbine read in step S4, determine whether the blade root load control flag is set to True. If the blade root load control flag is True, execute step S7. If the blade root load control flag is not True, return to step S4, which includes the following steps: Based on the wind turbine blade root load and the wind speed, rotation speed, and pitch angle values ​​of the wind turbine read in step S4, it is determined whether the maximum value of the combined bending moment Mxy is greater than a preset threshold value S1, the maximum deviation value of the My load is greater than a preset deviation threshold value S2, and the differential value of the combined bending moment Mxy is continuously greater than a preset differential threshold value S3 within time T0. If so, the blade root load control flag is set to True and step S7 is executed. If not, the process returns to step S4. S7, superimposing an additional retraction instruction Δθ on each blade of the wind turbine, setting a timer to start timing, and executing step S8; S8. According to the blade root load of the wind turbine generator set and the wind speed, rotation speed and pitch angle values ​​of the wind turbine generator set read in step S4, determine whether the blade root load control flag is set to False. If the blade root load control flag is False, reset the timer to zero at the same time to complete the reduction of the blade root load of the wind turbine generator set. If the blade root load control flag is not False, return to step S4.

2. A wind turbine blade root load reduction control method according to claim 1, characterized in that: The step S1 comprises the following steps: Load sensors are set in the swing and flapping directions of each blade root section of the wind turbine to form a blade root load sensor system to obtain the blade root Mx and My load calibration.

3. The wind turbine blade root load reduction control method according to claim 1, characterized in that: The step S2 comprises the following steps: According to the blade root load sensor system and the built-in measurement system of the wind turbine, the wind turbine blade root Mx and My load calibration as well as the wind speed, rotation speed and pitch angle values ​​of the wind turbine are collected; wherein, the built-in measurement system of the wind turbine includes an anemometer, a pitch angle measuring instrument, a rotation speed slip ring sensor and a storage control module unit.

4. A wind turbine blade root load reduction control method according to claim 3, characterized in that: In step S3, filtering the wind speed, rotation speed and pitch angle value of the wind turbine generator system includes the following steps: The wind speed, rotational speed and pitch angle values ​​of the wind turbine are collected and filtered, and the filtered variable values ​​are sent to the storage control module unit of the wind turbine; wherein the wind speed filter is a sliding average filter, the rotational speed filter is a second-order low-pass filter and the pitch angle filter is a second-order notch filter.

5. The wind turbine blade root load reduction control method according to claim 1, characterized in that: The step S5 comprises the following steps: According to the wind turbine blade root load and the wind speed, rotation speed and pitch angle values ​​of the wind turbine read in step S4, it is determined whether the measured pitch angle is greater than the preset pitch angle threshold θ0, the filtered wind speed is greater than the preset wind speed threshold W0, and the measured rotation speed exceeds the rated rotation speed Ω0. If so, it is determined that the wind turbine is in normal power generation mode and step S6 is executed. If not, the process returns to step S4.

6. The wind turbine blade root load reduction control method according to claim 1, characterized in that: The step S8 comprises the following steps: According to the wind turbine blade root load and the wind speed, rotation speed and pitch angle values ​​of the wind turbine read in step S4, it is determined whether the maximum value of the combined bending moment Mxy is less than the preset threshold S1 or whether the timer exceeds the given time. If so, the blade root load control flag is set to False and the timer is reset to zero to complete the reduction of the wind turbine blade root load. If not, return to step S4.

7. A wind turbine blade root load reduction control system, characterized in that: A method for controlling blade root load reduction of a wind turbine set according to any one of claims 1 to 6, the system comprising a blade root load sensor system, an anemometer, a pitch angle measuring instrument, a speed slip ring sensor, and a programmable storage control module unit, wherein the anemometer, the pitch angle measuring instrument, the speed slip ring sensor, and the programmable storage control module unit are all built into the wind turbine set, and the blade root load sensor system comprises a plurality of load sensors arranged in the swing and flapping directions of each blade root section of the wind turbine set.

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