A control method and system for load reduction of a wind turbine in a feathering condition

Abstract

The application discloses a control method and system for load reduction of a wind turbine in a stuck condition, and the wind turbine is operated near a cut-out wind speed and is in the stuck condition. During shutdown of the wind turbine, a non-stuck blade variable pitch rate compensation value is calculated according to a blade azimuth angle of the wind turbine, a nacelle wind speed or a front wind speed and a real-time angle of the non-stuck blade, and the compensation value is superimposed on a given value of a segmented variable pitch rate obtained based on the angle of the non-stuck blade in an original stuck condition scheme, so as to reduce asymmetry of three blade flapwise bending moments when the angle of the non-stuck blade is operated in a set range.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind turbine control, and particularly to a wind turbine stuck-pitch condition load reduction control method, system, storage medium and computing device. BACKGROUND

[0002] When the wind turbine operates near the cut-out wind speed, due to the occurrence of an unrecoverable fault in the mechanical components or electrical subsystems of the pitch actuator, the pitch angle of the corresponding blade is continuously maintained at the value at the time of the fault, which is usually referred to as the stuck-pitch condition.

[0003] During the stuck-pitch condition and the execution of the shutdown process, the converter outputs the electromagnetic torque according to the given value of the electromagnetic torque obtained by looking up the generator speed table. The pitch angle of the blade that is not stuck is increased according to the set value of the segmented pitch rate obtained by looking up the real-time pitch angle of the blade.

[0004] When the pitch angle of the blade that is not stuck is increased to the range of 30-50 deg, the real-time flapwise moment of the stuck blade remains at a high value, while the real-time flapwise moment of the blade that is not stuck quickly decreases, resulting in a large asymmetry in the flapwise moments of the three blades, which easily leads to large loads of the hub center combined moment and the yaw bearing combined moment in the rotating coordinate system. As the length of the blade increases, the loads of the hub center combined moment and the yaw bearing combined moment become larger, which may become the dominant limit load of the main shaft or the yaw bearing. SUMMARY

[0005] A first object of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a wind turbine stuck-pitch condition load reduction control method that can attenuate the load of the hub center combined moment Myz in the rotating coordinate system during the stuck-pitch condition shutdown process, and reduce the limit load of the main shaft and other components when the stuck-pitch condition dominates. The method can also attenuate the load of the yaw bearing combined moment Mxy during the stuck-pitch condition shutdown process, and reduce the limit load of the yaw bearing when the stuck-pitch condition dominates.

[0006] A second object of the present application is to provide a wind turbine stuck-pitch condition load reduction control system.

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

[0008] A 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 load reduction of a wind turbine in a stuck condition, the method being for a wind turbine operating near a cut-out wind speed and in a stuck condition, during its shutdown process, calculating a compensation value of the variable pitch rate of the unstuck blade according to the azimuth angle of the impeller, the nacelle wind speed or the front wind speed and the real-time angle of the unstuck blade, and superimposing the compensation value on the given value of the segmented variable pitch rate obtained based on the angle of the unstuck blade in the original stuck condition scheme, so as to reduce the asymmetry of the three blade flapwise bending moments when the angle of the unstuck blade runs in a set range.

[0010] Further, the control method for load reduction of the wind turbine in the stuck condition performs the following operations:

[0011] When the wind turbine operates in a grid-connected power generation mode, a nacelle wind speed signal is collected and filtered by a low-pass filter to obtain a filtered nacelle wind speed;

[0012] The filtered nacelle wind speed, the azimuth angle of the impeller and the real-time angle of the unstuck blade are taken as inputs of an unstuck blade variable pitch rate compensation module;

[0013] During the shutdown process of the wind turbine operating near the cut-out wind speed and monitoring the stuck condition, the unstuck blade variable pitch rate compensation module calculates a compensation value of the variable pitch rate of the unstuck blade according to the azimuth angle of the impeller, the filtered nacelle wind speed and the real-time blade angle, and takes the compensation value as one of the given values of the variable pitch rate of the unstuck blade during the shutdown process of the stuck condition;

[0014] During the shutdown process of the wind turbine operating near the cut-out wind speed and monitoring the stuck condition, the unstuck blade queries a corresponding given value of the variable pitch rate in a segmented variable pitch rate setting table according to the real-time blade angle, and takes the given value as the second given value of the variable pitch rate of the unstuck blade during the shutdown process of the unstuck blade;

[0015] The first given value of the variable pitch rate of the unstuck blade is superimposed on the second given value of the variable pitch rate of the unstuck blade, and then an integral operation is performed to obtain a given value of the pitch position of the unstuck blade during the shutdown process;

[0016] The given value of the pitch position of the unstuck blade during the shutdown process is executed by the respective pitch actuator, so as to reduce the asymmetry of the three blade flapwise bending moments when the angle of the unstuck blade runs in a set range, and to achieve the purpose of attenuating the maximum values of the hub center bending moment and the yaw bearing bending moment in the rotating coordinate system.

[0017] Further, the nacelle wind speed signal is provided by a mechanical anemometer installed on the top of the nacelle cover, wherein for a wind turbine equipped with a nacelle laser radar, the nacelle wind speed signal adopts a front wind speed measured by the laser radar.

[0018] Further, the impeller azimuth angle is provided by an absolute value rotary encoder installed in the hub.

[0019] Further, the transfer function of the low-pass filter is as follows:

[0020] Or

[0021] In the formula, s is a complex variable, T is a time constant of a first-order low-pass filter, ξ is a damping ratio of a second-order low-pass filter, and ω is a cutoff frequency of the second-order low-pass filter.

[0022] Further, the set range is 30-50 deg.

[0023] The second object of the application is achieved by the following technical solution: a control system for a wind turbine in a pitch-stuck working condition for load reduction, which is used to implement the control method for the wind turbine in the pitch-stuck working condition, and comprises:

[0024] A data acquisition and processing module is configured to acquire a nacelle wind speed signal when the wind turbine operates in a grid-connected power generation mode, and obtain a filtered nacelle wind speed by filtering through a low-pass filter, and use the filtered nacelle wind speed, an impeller azimuth angle, and a real-time angle of a non-pitch-stuck blade as inputs of a non-pitch-stuck blade variable pitch rate compensation module.

[0025] A first calculation module is configured to, when the wind turbine operating near a cut-out wind speed monitors a pitch-stuck working condition and executes a shutdown process, calculate a variable pitch rate compensation value of the non-pitch-stuck blade according to the impeller azimuth angle, the filtered nacelle wind speed, and a real-time blade angle of a corresponding blade, and use the variable pitch rate compensation value as one of non-pitch-stuck blade variable pitch rate given values in the pitch-stuck working condition shutdown process.

[0026] A second calculation module is configured to, when the wind turbine operating near the cut-out wind speed monitors the pitch-stuck working condition and executes the shutdown process, query a corresponding variable pitch rate given value from a segmented variable pitch rate setting table according to the real-time blade angle, and use the variable pitch rate given value as the second of the non-pitch-stuck blade variable pitch rate given values in the non-pitch-stuck blade shutdown process.

[0027] A data processing module is configured to superimpose the first of the non-pitch-stuck blade variable pitch rate given values on the second of the non-pitch-stuck blade variable pitch rate given values, and then perform integral operation to obtain a variable pitch position given value in the non-pitch-stuck blade shutdown process.

[0028] An execution module is configured to execute the variable pitch position given value in the non-pitch-stuck blade shutdown process by respective pitch execution mechanisms, so as to reduce the asymmetry of the three blade edgewise bending moments in the flapwise direction when the non-pitch-stuck blade angle operates in a set range, and achieve the purpose of attenuating the maximum value of the hub center combined bending moment and the yaw bearing combined bending moment in the rotating coordinate system.

[0029] The third object of the present application is achieved by the following technical solution: a storage medium storing a program, which, when executed by a processor, implements the wind turbine pitch loss control method in the pitch loss condition.

[0030] 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, which, when executed by the processor, implements the wind turbine pitch loss control method in the pitch loss condition.

[0031] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0032] 1. Attenuate the Myz load of the hub center in the rotating coordinate system during the pitch loss shutdown process, and reduce the ultimate load of the main shaft and other components when the condition dominates.

[0033] 2. Attenuate the Mxy load of the yaw bearing during the pitch loss shutdown process, and reduce the ultimate load of the yaw bearing when the condition dominates.

[0034] 3. No need to add any additional hardware devices, good economy. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The working principle diagram of the load reduction scheme during the pitch loss and shutdown process of the blade 1 operating near the cut-out wind speed.

[0036] Figure 2 The comparison diagram of the Bladed simulation time sequence of the flapwise bending moment of the blade 1 root during the opening and closing of the load reduction scheme during the pitch loss and shutdown process of the blade 1 operating near the cut-out wind speed.

[0037] Figure 3 The comparison diagram of the Bladed simulation time sequence of the flapwise bending moment of the blade 2 root during the opening and closing of the load reduction scheme during the pitch loss and shutdown process of the blade 1 operating near the cut-out wind speed.

[0038] Figure 4 The comparison diagram of the Bladed simulation time sequence of the flapwise bending moment of the blade 3 root during the opening and closing of the load reduction scheme during the pitch loss and shutdown process of the blade 1 operating near the cut-out wind speed.

[0039] Figure 5 The comparison diagram of the Bladed simulation time sequence of the hub center combined bending moment in the rotating coordinate system during the opening and closing of the load reduction scheme during the pitch loss and shutdown process of the blade 1 operating near the cut-out wind speed.

[0040] Figure 6The yaw bearing bending moment Bladed simulation timing comparison diagram when the load shedding scheme is turned on and off during the process of the blade 1 running near the cut-out wind speed, being stuck and shutdown.

[0041] Figure 7 The architecture diagram of the system of the application. DETAILED DESCRIPTION

[0042] The application will be further described in conjunction with the embodiments and the accompanying drawings, but the embodiments of the application are not limited thereto.

[0043] Embodiment 1

[0044] The embodiment discloses a control method for load shedding of a wind turbine in a stuck blade condition, which is for a wind turbine running near a cut-out wind speed and in a stuck blade condition, and in the shutdown process thereof, a stuck blade pitch rate compensation value is calculated according to a blade azimuth angle of the wind turbine, a nacelle wind speed or a front wind speed and a real-time angle of a non-stuck blade, and the stuck blade pitch rate compensation value is superimposed on a given value of a segmented pitch rate obtained based on the angle of the non-stuck blade in the original stuck blade condition scheme, so as to reduce the asymmetry of three blade edgewise bending moments in the flapwise direction when the angle of the non-stuck blade runs in a set range, and the specific execution is as follows:

[0045] When the wind turbine runs in a grid-connected power generation mode, a nacelle wind speed signal is collected, and the nacelle wind speed signal is provided by a mechanical anemometer installed on the top of a nacelle cover; for a wind turbine with a nacelle laser radar, the nacelle wind speed signal adopts a front wind speed measured by the laser radar;

[0046] The wind speed signal measured by the mechanical anemometer or the front wind speed measured by the laser radar is filtered through a low-pass filter to obtain a filtered wind speed signal;

[0047] The transfer function of the low-pass filter is as follows:

[0048] Or

[0049] In the formula, s is a complex variable, T is a time constant of a first-order low-pass filter, ξ is a damping ratio of a second-order low-pass filter, and ω is a cutoff frequency of the second-order low-pass filter;

[0050] Figure 1 The working principle diagram of the load shedding scheme during the process of the wind turbine running near the cut-out wind speed, the blade 1 being in a stuck blade condition and executing a shutdown process. For similar cases where only the blade 2 or the blade 3 is stuck, the application will not be described.

[0051] The blade pitch angle (provided by an absolute value rotary encoder installed in the hub), the filtered nacelle wind speed, and the un-locked blade 2, blade 3 blade angle are input to the un-locked blade variable pitch rate compensation module. The output of the un-locked blade variable pitch rate compensation module, i.e. the blade 2, blade 3 variable pitch rate compensation value, is one of the un-locked blade variable pitch rate given values during the locked blade shutdown process.

[0052] According to the real-time blade 2, blade 3 blade angle, the corresponding variable pitch rate given value is queried in the segmented variable pitch rate setting table, and is the second un-locked blade variable pitch rate given value during the un-locked blade shutdown process.

[0053] One of the un-locked blade variable pitch rate given values is superimposed on the second un-locked blade variable pitch rate given value, and then integrated to obtain the variable pitch position given value during the un-locked blade shutdown process, i.e. the blade 2, blade 3 variable pitch position given value.

[0054] The variable pitch position given value during the un-locked blade shutdown process is executed by the respective variable pitch actuator, and when the un-locked blade blade angle operates in the 30-50 deg interval, the asymmetry of the three blade flapwise bending moments is reduced, so as to attenuate the maximum value of the hub center combined bending moment and the yaw bearing combined bending moment in the rotating coordinate system.

[0055] Figure 2 For a wind turbine operating near the cut-out wind speed, when the blade 1 occurs in the locked blade condition and executes the shutdown process, the blade 1 blade root flapwise bending moment is still at a high value in the 60-70 s interval when the load shedding scheme is opened and closed.

[0056] Figure 3 For a wind turbine operating near the cut-out wind speed, when the blade 1 occurs in the locked blade condition and executes the shutdown process, the blade 2 blade root flapwise bending moment decreases more when the load shedding scheme is closed in the 60-70 s interval, and the blade 2 blade root flapwise bending moment increases when the load shedding scheme is opened, and the asymmetry of the blade 1 blade root flapwise bending moment is reduced.

[0057] Figure 4 For a wind turbine operating near the cut-out wind speed, when the blade 1 occurs in the locked blade condition and executes the shutdown process, the blade 3 blade root flapwise bending moment decreases more when the load shedding scheme is closed in the 60-70 s interval, and the blade 3 blade root flapwise bending moment increases when the load shedding scheme is opened, and the asymmetry of the blade 1 blade root flapwise bending moment is reduced.

[0058] Figure 5 For the wind turbine running near the cut-out wind speed, when the blade 1 occurs the pitch-in condition and executes the shutdown process, the hub center bending moment Bladed simulation time sequence comparison when the load shedding scheme is opened and closed, the maximum value of the yaw bearing bending moment of the opening load shedding scheme has a large amplitude attenuation.

[0059] Figure 6 For the wind turbine running near the cut-out wind speed, when the blade 1 occurs the pitch-in condition and executes the shutdown process, the hub center bending moment Bladed simulation time sequence comparison when the load shedding scheme is opened and closed, the maximum value of the yaw bearing bending moment of the opening load shedding scheme has a large amplitude attenuation.

[0060] Embodiment 2

[0061] The embodiment discloses a control system for pitch-in condition load shedding of a wind turbine, which is used to realize the control method for pitch-in condition load shedding of the wind turbine in embodiment 1, as shown in the figure, the system comprises the following functional modules: Figure 7

[0062] The data acquisition and processing module is used to acquire the nacelle wind speed signal when the wind turbine is running in the grid-connected power generation mode, and obtain the filtered nacelle wind speed through a low-pass filter, and the filtered nacelle wind speed, the blade azimuth angle and the real-time angle of the non-pitch-in blade are used as the input of the non-pitch-in blade variable pitch rate compensation module;

[0063] The first calculation module is used to calculate the variable pitch rate compensation value of the non-pitch-in blade according to the blade azimuth angle, the filtered nacelle wind speed and the real-time blade angle of the corresponding blade when the wind turbine running near the cut-out wind speed monitors the pitch-in condition and executes the shutdown process, and the variable pitch rate compensation value is used as one of the non-pitch-in blade variable pitch rate given values in the pitch-in condition shutdown process;

[0064] The second calculation module is used to query the corresponding variable pitch rate given value in the segmented variable pitch rate setting table according to the real-time blade angle of the non-pitch-in blade when the wind turbine running near the cut-out wind speed monitors the pitch-in condition and executes the shutdown process, and the variable pitch rate given value is used as the second of the non-pitch-in blade variable pitch rate given values in the shutdown process of the non-pitch-in blade;

[0065] The data processing module is used to superimpose one of the non-pitch-in blade variable pitch rate given values on the second of the non-pitch-in blade variable pitch rate given values, and then perform integral operation to obtain the variable pitch position given value in the shutdown process of the non-pitch-in blade;

[0066] ​The execution module is used for giving the pitch position value of the un-stuck blade in the shutdown process by the respective pitch execution mechanism, and reducing the asymmetry of the three blade flapwise bending moments when the un-stuck blade blade angle runs in the set range, so as to achieve the purpose of attenuating the maximum value of the hub center combined bending moment and the yaw bearing combined bending moment in the rotating coordinate system.

[0067] Embodiment 3

[0068] The embodiment discloses a storage medium, which stores a program, and the program is executed by a processor to realize the control method for reducing load in the stuck blade working condition of the wind power generator.

[0069] 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.

[0070] Embodiment 4

[0071] The embodiment discloses a computing device, which comprises a processor and a memory for storing a program executable by the processor, and the processor executes the program stored in the memory to realize the control method for reducing load in the stuck blade working condition of the wind power generator.

[0072] 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.

[0073] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, which are all included in the protection scope of the present application.

Claims

1. A method for controlling load shedding in a wind turbine blade stuck condition, characterized in that: This method is for a wind turbine operating near the cut-out wind speed and experiencing a stuck blade condition. During its shutdown process, the method calculates the pitch rate compensation value of the unstuck blade based on the wind turbine's rotor azimuth, the nacelle wind speed or the leading wind speed, and the real-time angle of the unstuck blade. The calculated value is then superimposed on the segmented pitch rate given value obtained based on the unstuck blade angle in the original stuck blade condition scheme to reduce the asymmetry of the three blade flapping direction bending moments when the blade angle of the unstuck blade operates within the set range. The following operations are performed: When the wind turbine is operating in the grid-connected power generation mode, the nacelle wind speed signal is collected and filtered through a low-pass filter to obtain the filtered nacelle wind speed; The filtered nacelle wind speed, impeller azimuth angle, and real-time angle of the unstuck blade are used as inputs to the unstuck blade pitch rate compensation module; When a wind turbine operating near the cut-out wind speed detects a stuck blade condition and executes a shutdown, the unstuck blade pitch rate compensation module calculates the unstuck blade pitch rate compensation value based on the impeller azimuth, filtered nacelle wind speed, and the corresponding blade's real-time blade angle. This value is used as one of the unstuck blade pitch rate given values ​​during the stuck blade shutdown process. When a wind turbine operating near the cut-out wind speed detects a stuck blade condition and is shutting down, the corresponding pitch rate setting value of the unstuck blade is retrieved from the segmented pitch rate setting table based on the real-time blade angle, and the value is used as the second pitch rate setting value of the unstuck blade during the shutdown process; One of the unstuck blade pitch rate set values ​​is superimposed on the second unstuck blade pitch rate set value, and then integrated to obtain the pitch position set value during the unstuck blade shutdown process; The pitch position given values ​​during the shutdown process of the unstuck blades are executed by their respective pitch actuators. When the blade angles of the unstuck blades operate within the set range, the asymmetry of the bending moments in the flapping directions of the three blades is reduced, thereby achieving the purpose of attenuating the maximum values ​​of the hub center bending moment and the yaw bearing bending moment in the rotating coordinate system.

2. The method for controlling load shedding in a wind turbine generator stuck blade condition according to claim 1, characterized in that: The nacelle wind speed signal is provided by a mechanical anemometer installed on the top of the nacelle cover. For a wind turbine equipped with a nacelle-type lidar, the nacelle wind speed signal adopts the front wind speed measured by the lidar.

3. The method for controlling load shedding in a wind turbine blade stuck condition according to claim 1, characterized in that: The impeller azimuth angle is provided by an absolute value rotary encoder installed in the hub.

4. The method for controlling load shedding in a wind turbine blade stuck condition according to claim 1, characterized in that: The transfer function of the low-pass filter is as follows: or ; Where, is a complex variable, is the time constant of the first-order low-pass filter, is the damping ratio of the second-order low-pass filter, is the cutoff frequency of the second-order low-pass filter.

5. The method for controlling load shedding in a wind turbine blade stuck condition according to claim 1, characterized in that: The setting range is 30 to 50 degrees.

6. A control system for load reduction in a wind turbine blade stuck condition, characterized in that: A control method for achieving load reduction in a wind turbine in a pitch-stuck condition according to any one of claims 1 to 5, comprising: The data acquisition and processing module is used to collect the nacelle wind speed signal when the wind turbine is operating in the grid-connected power generation mode, and obtain the filtered nacelle wind speed through a low-pass filter. The filtered nacelle wind speed, the impeller azimuth angle and the real-time angle of the unstuck blade are used as the input of the unstuck blade pitch rate compensation module; A first calculation module is configured to calculate, when a wind turbine operating near a cut-out wind speed detects a stuck blade condition and is shutting down, a pitch rate compensation module for unstuck blades based on the impeller azimuth, the filtered nacelle wind speed, and the real-time blade angle of the corresponding blade, and to obtain a pitch rate compensation value for the unstuck blades as one of the given pitch rate values ​​for the unstuck blades during the shutdown process under the stuck blade condition; The second calculation module is used for, when a wind turbine operating near the cut-out wind speed detects a stuck blade condition and executes a shutdown process, querying the corresponding pitch rate setting value of the unstuck blade in the segmented pitch rate setting table based on the real-time blade angle, and using the corresponding pitch rate setting value as the second pitch rate setting value of the unstuck blade during the shutdown process; a data processing module for superimposing one of the unstuck blade pitch rate given values ​​on the second unstuck blade pitch rate given value, and then performing an integral operation to obtain a pitch position given value during the unstuck blade shutdown process; The execution module is used to respectively execute the pitch position given values ​​during the shutdown process of the unstuck blades by the respective pitch actuators. When the blade angles of the unstuck blades operate within the set range, the asymmetry of the bending moments in the flapping directions of the three blades is reduced, so as to achieve the purpose of attenuating the maximum values ​​of the hub center bending moment and the yaw bearing bending moment in the rotating coordinate system.

7. A storage medium storing a program, characterized in that: When the program is executed by a processor, the control method for load reduction in a wind turbine in a pitch-stuck condition according to any one of claims 1 to 5 is implemented.

8. A computing device comprising a processor and a memory for storing a program executable by the processor, characterized in that: When the processor executes the program stored in the memory, the control method for load reduction in the wind turbine stuck pitch condition according to any one of claims 1 to 5 is implemented.

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