A wind turbine overspeed prevention control method and system based on variable pitch motor torque

Abstract

The application discloses a wind turbine anti-over-speed control method and system based on a variable pitch motor torque, which comprises the following steps: obtaining the variable pitch motor torque of the wind turbine, and identifying the over-speed working condition of the wind turbine by using the variable pitch motor torque; setting a variable pitch angle table corresponding to the variable pitch motor torque according to the difference between the variable pitch motor torque in the normal working condition and the over-speed working condition of the wind turbine; collecting real-time variable pitch motor torque signals, filtering the collected variable pitch motor torque signals, searching the variable pitch angle table through linear interpolation, and obtaining the corresponding minimum pitch angle; and using the minimum pitch angle to control the lifting of the wind turbine blade angle and reduce the generator speed, so as to realize the generator anti-over-speed control of the wind turbine. The application can identify whether the wind turbine is over-speed by using a non-rotational speed signal, can avoid the problems of the existing technologies such as transmission chain slip or low measurement value, and can reduce the load of the unit components in the over-speed working condition, and has a good reducing effect on the limit load of the blades, the rotating hub, the fixed hub and the tower.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fan anti-over-speed control, in particular to a fan anti-over-speed control method and system based on a variable pitch motor torque. BACKGROUND

[0002] The existing technology measures the generator speed by using a slip ring encoder, thereby guiding the blade angle and torque to control the generator speed. The wind power slip ring encoder is installed on the slip ring, the slip ring main shaft is connected with the main machine gear box shaft to realize rotation. The slip ring shell is externally connected with a limiting plate to prevent the shell from tilting. The encoder is a precise rotation speed measuring device, and the fan unit monitors the rotation speed by sampling the encoder output pulse, and alarms and stops when the monitoring value is out of tolerance.

[0003] However, the measurement of the generator speed by using the slip ring encoder has the following technical problems:

[0004] 1. Transmission chain slip: the generator speed decreases, but the impeller speed does not, at this time, the opening of the blade increases the generator speed, which further increases the impeller speed, and the flywheel phenomenon is easy to occur;

[0005] 2. Error in setting the rated speed: the blade angle and torque are set according to the wrong rated speed to make the generator speed reach the value, if the rated speed is set too high, the unit load will be larger, and the tower will be easy to fall;

[0006] 3. Measurement of the slip ring encoder is low: the actual generator speed has reached the rated speed, but the measured value is low, which further increases the generator speed, and the unit load will be larger, and the tower will be easy to fall. SUMMARY

[0007] The present application aims to overcome the shortcomings of the prior art, and provides a fan anti-over-speed control method and system based on a variable pitch motor torque, which realizes anti-over-speed control through the torque of the variable pitch motor, thereby avoiding the problems caused by measuring the speed by using the slip ring encoder.

[0008] The purpose of the present application is achieved by the following technical scheme: a fan anti-over-speed control method based on a variable pitch motor torque, comprising:

[0009] Obtaining the variable pitch motor torque of the fan, and identifying the over-speed working condition of the fan by using the variable pitch motor torque;

[0010] According to the difference between the variable pitch motor torque of the normal working condition and the over-speed working condition of the fan, a variable pitch motor torque corresponding variable pitch angle table is set;

[0011] Collecting the real-time variable pitch motor torque signal, filtering the collected variable pitch motor torque signal, and searching the variable pitch angle table after linear interpolation to obtain the corresponding minimum pitch angle FinePitch;

[0012] The minimum pitch angle FinePitch is used to control the lifting fan blade angle, reduce the generator speed, and realize the generator overspeed protection control of the fan.

[0013] Further, the pitch motor torque of the fan is acquired, and the pitch motor torque is used to identify the overspeed working condition of the fan, including:

[0014] At a preset wind speed, the pitch motor torque is acquired, and it is judged whether the pitch motor torque exceeds a preset range. If the pitch motor torque exceeds the preset range, it is judged that the fan is in the overspeed working condition. If the pitch motor torque does not exceed the preset range, the fan is not in the overspeed working condition.

[0015] Further, according to the difference between the pitch motor torques in the normal working condition and the overspeed working condition of the fan, a pitch angle table corresponding to the pitch motor torque is set, including:

[0016] The rated wind speed of the normal working condition of the fan and the rated wind speed ± 2 m / s of the normal working condition are simulated, the filtered pitch torques of each blade of the fan are viewed, the maximum value in the pitch torques is taken as A, and when the pitch torque of the fan is A, the corresponding blade pitch angle is the optimal pitch angle of the pitch torque A.

[0017] The rated wind speed of the overspeed working condition and the rated wind speed ± 2 m / s of the overspeed working condition are simulated, the filtered pitch torques of each blade of the fan are viewed, the minimum value in the pitch torques is taken as B, and then the pitch angles of the blades are viewed, the average value of the pitch angles is taken as C, and when the pitch torque of the fan is B, the corresponding blade pitch angle is C.

[0018] According to the corresponding relationship between the pitch torques and the pitch angles in the normal working condition and the overspeed working condition, a pitch angle table is set.

[0019] Further, the acquired pitch motor torque signal is filtered, and the pitch angle table is searched after linear interpolation, including:

[0020] A low-pass filter is used to remove the high-frequency signals in the pitch motor torque signal, and the formula is as follows:

[0021]

[0022] Wherein, G(s) is a transfer function, ξ is a damping coefficient, ω0 is a natural frequency, and s is a complex frequency.

[0023] The linear interpolation formula is as follows:

[0024]

[0025] Wherein, x0 and x1 are the horizontal coordinates of the known points, y0 and y1 are the vertical coordinates of the known points, x is the horizontal coordinate of the unknown point, and y is the vertical coordinate of the unknown point.

[0026] Further, the low-pass filter is a second-order low-pass filter.

[0027] A wind turbine overspeed prevention control system based on a variable pitch motor torque is used to implement the wind turbine overspeed prevention control method based on a variable pitch motor torque, comprising:

[0028] A torque acquisition unit is configured to acquire the variable pitch motor torque of the wind turbine.

[0029] An operating condition identification unit is configured to identify the overspeed operating condition of the wind turbine according to the variable pitch motor torque.

[0030] A variable pitch angle table setting unit is configured to set a variable pitch angle table corresponding to the variable pitch motor torque according to the difference between the variable pitch motor torque in the normal operating condition and the variable pitch motor torque in the overspeed operating condition.

[0031] A filtering unit is configured to filter the acquired real-time variable pitch motor torque signal.

[0032] A minimum pitch angle acquisition unit is configured to obtain the minimum pitch angle FinePitch corresponding to the real-time variable pitch motor torque by linear interpolation and checking the variable pitch angle table.

[0033] A control unit is configured to input the minimum pitch angle FinePitch to control the lifting of the wind turbine blade angle and reduce the generator speed, thereby achieving the generator overspeed prevention control of the wind turbine.

[0034] Further, the operating condition identification unit is configured to perform the following operations:

[0035] It is determined whether the acquired variable pitch motor torque exceeds the preset range. If it exceeds the preset range, it is determined that the wind turbine is in the overspeed operating condition. If it does not exceed the preset range, the wind turbine is not in the overspeed operating condition.

[0036] Further, the variable pitch angle table setting unit is configured to perform the following operations:

[0037] The rated wind speed of the normal operating condition of the simulated wind turbine and the rated wind speed ± 2m / s of the normal operating condition are simulated, the filtered variable pitch torque of each blade of the wind turbine is viewed, the maximum value of the variable pitch torque is taken as A, and when the variable pitch torque of the wind turbine is A, the corresponding blade pitch angle is the optimal pitch angle of the variable pitch torque A.

[0038] The rated wind speed of the overspeed operating condition of the simulated wind turbine and the rated wind speed ± 2m / s of the overspeed operating condition are simulated, the filtered variable pitch torque of each blade of the wind turbine is viewed, the minimum value of the variable pitch torque is taken as B, and the pitch angle of the blade is viewed again, the average value of the pitch angle is taken as C, and when the variable pitch torque of the wind turbine is B, the corresponding blade pitch angle is C.

[0039] According to the correspondence relationship between the pitch torque and the pitch angle under normal working conditions and overspeed working conditions, a pitch angle table is set.

[0040] A non-transitory computer readable medium storing instructions which, when executed by a processor, perform the steps of the wind turbine overspeed prevention control method based on the pitch motor torque according to the above.

[0041] A computing device comprising a processor and a memory for storing a processor-executable program, wherein the processor implements the wind turbine overspeed prevention control method based on the pitch motor torque according to the above when executing the program stored in the memory.

[0042] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0043] 1. The present application can identify whether the wind turbine is overspeed through a non-rotational speed signal, which can avoid the problems of the prior art such as transmission chain slip or low measurement value;

[0044] 2. The present application does not need to increase new hardware costs and can be implemented on the original wind turbine hardware;

[0045] 3. The present application can reduce the load of the unit components under overspeed working conditions, and has good reducing effect on the limit load of the blades, rotating hubs, fixed hubs and towers. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 A variable pitch motor torque comparison graph under different wind speeds.

[0047] Figure 2 A variable pitch motor torque limit value graph under different wind speeds.

[0048] Figure 3 A variable pitch motor torque comparison graph under DLC2.2a overspeed working conditions.

[0049] Figure 4 A variable pitch motor torque limit value graph under DLC2.2a overspeed working conditions.

[0050] Figure 5 A verification unit overspeed working condition simulation result table.

[0051] Figure 6 A blade root My load comparison graph.

[0052] Figure 7 A filtered real-time variable pitch motor torque comparison graph.

[0053] Figure 8 A blade angle and variable pitch motor torque comparison graph.

[0054] Figure 9This is a generator speed comparison curve.

[0055] Figure 10 This is a generator torque comparison curve. DETAILED DESCRIPTION

[0056] The present invention will be further described below with reference to specific embodiments.

[0057] Example 1

[0058] The wind turbine overspeed prevention control method based on pitch motor torque provided in this embodiment includes:

[0059] 1) Obtain the wind turbine’s pitch motor torque and use it to identify the wind turbine’s overspeed condition:

[0060] See also Figures 1-2 As shown in Figure 2, near the rated wind speed, the pitch motor torque is maximum; under power-limited conditions, at the same wind speed, the blade angle is larger and the pitch motor torque is smaller. Figures 3-4 According to the IEC61400 wind turbine design specification, under the same wind speed in the overspeed condition (DLC2.1a, DLC2.2a), the blade angle is smaller and the pitch motor torque will be larger, exceeding the normal value range; therefore, under the preset wind speed, the pitch motor torque is obtained to determine whether the pitch motor torque exceeds the preset range. If it exceeds the preset range, it is determined that the wind turbine is in an overspeed condition at this time. If it does not exceed the preset range, the wind turbine is not in an overspeed condition.

[0061] 2) According to the difference in pitch motor torque between normal and overspeed conditions of the wind turbine, a pitch angle table corresponding to pitch motor torque is set, including:

[0062] Simulate the rated wind speed of wind turbine DLC1.2 under normal operating conditions and the rated wind speed ±2m / s under normal operating conditions. Check the filtered pitch torque of each wind turbine blade and take the maximum value of the pitch torque, which is recorded as A. When the wind turbine pitch torque is A, the corresponding blade pitch angle is the optimal pitch angle for the pitch torque A.

[0063] Simulate the rated wind speed of the DLC2.2a overspeed condition and the rated wind speed ±2m / s for this overspeed condition. Check the filtered pitch torque of each wind turbine blade and take the minimum value of the pitch torque as B. Then check the blade pitch angle and take the average value of the pitch angle as C. When the wind turbine pitch torque is B, the corresponding blade pitch angle is C.

[0064] According to the corresponding relationship between the pitch torque and pitch angle under normal working conditions and overspeed working conditions, the pitch angle table is set as shown in Table 1 below:

[0065] Pitch motor torque A B Pitch angle Optimal pitch angle C

[0066] Table 1 Pitch Angle Table

[0067] 3) Collect the real-time pitch motor torque signal, filter the collected pitch motor torque signal, and check the pitch angle table after linear interpolation to obtain the corresponding minimum pitch angle FinePitch, including:

[0068] A low-pass filter is used to remove high-frequency signals from the pitch motor torque signal. The formula is as follows:

[0069]

[0070] Where G(s) is the transfer function, ξ is the damping coefficient, ω0 is the natural frequency, and s is the complex frequency;

[0071] The linear interpolation formula is as follows:

[0072]

[0073] Among them, x0 and x1 are the horizontal coordinates of the known points, y0 and y1 are the vertical coordinates of the known points, x is the horizontal coordinate of the unknown point, and y is the vertical coordinate of the unknown point.

[0074] 4) The minimum pitch angle FinePitch is used to control and increase the angle of each wind turbine blade, reduce the generator speed, and implement the wind turbine generator overspeed prevention control.

[0075] The verified unit is used, and its rated speed is 1146 rpm. Figure 5 As shown in the figure, in order to verify the simulation results of the overspeed condition of the unit, the DLC2.2a condition is selected for simulation verification. It can be seen that after adopting this strategy, the load reduction ratio of the blade root My is reduced by an average of 11.74%.

[0076] Take DLC2.2aa+01 working condition for detailed analysis; see Figures 6-10 As shown in the figure, after the strategy is activated, as the generator speed gradually increases, the pitch motor torque also increases synchronously. At approximately the 90th second, the strategy is triggered, and the pitch angle is increased by finepitch, causing the speed to drop and preventing the first overspeed. Because this operating condition is an overspeed condition and the unit must overspeed, the finepitch value was not set to a high value when designing the parameter table. The unit eventually overspeeds, but the blade angle at this time is higher than when the strategy is not activated, effectively reducing the blade root load.

[0077] Example 2

[0078] The wind turbine overspeed prevention control system based on pitch motor torque provided in this embodiment is used to implement the wind turbine overspeed prevention control method based on pitch motor torque described in Example 1, including:

[0079] a torque acquisition unit configured to acquire a pitch motor torque of the wind turbine;

[0080] a working condition identification unit configured to identify an overspeed working condition of the wind turbine according to the pitch motor torque;

[0081] a pitch angle table setting unit configured to set a pitch angle table corresponding to the pitch motor torque according to a difference between the pitch motor torque in the normal working condition and the pitch motor torque in the overspeed working condition;

[0082] a filtering unit configured to filter the acquired real-time pitch motor torque signal;

[0083] a minimum pitch angle acquisition unit configured to obtain a minimum pitch angle FinePitch corresponding to the real-time pitch motor torque by linear interpolation and looking up the pitch angle table;

[0084] a control unit configured to input the minimum pitch angle FinePitch to control the lifting of the wind turbine blade angle and the reduction of the generator speed, thereby realizing the generator overspeed prevention control of the wind turbine.

[0085] Embodiment 3

[0086] The embodiment discloses a non-transitory computer readable medium storing instructions, when the instructions are executed by a processor, the steps of the wind turbine overspeed prevention control method based on the pitch motor torque according to the embodiment 1 are executed.

[0087] 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.

[0088] Embodiment 4

[0089] 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 overspeed prevention control method based on the pitch motor torque according to the embodiment 1 is realized.

[0090] 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.

[0091] 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 wind turbine overspeed prevention control method based on pitch motor torque, characterized in that: include: Obtain the wind turbine's pitch motor torque and use it to identify the wind turbine's overspeed condition; According to the difference in pitch motor torque between normal and overspeed conditions of the wind turbine, a pitch angle table corresponding to pitch motor torque is set, including: Simulate the rated wind speed of the wind turbine under normal operating conditions and the rated wind speed ±2m / s under normal operating conditions, check the filtered pitch torque of each blade of the wind turbine, take the maximum value of the pitch torque, and record it as A. When the wind turbine pitch torque is A, the corresponding blade pitch angle is the optimal pitch angle of the pitch torque A; Simulate the rated wind speed of the overspeed condition and the rated wind speed ±2m / s for the overspeed condition, check the filtered pitch torque of each blade of the wind turbine, take the minimum value of the pitch torque and record it as B, then check the blade pitch angle, take the average value of the pitch angle and record it as C. When the wind turbine pitch torque is B, the corresponding blade pitch angle is C; According to the corresponding relationship between the pitch torque and pitch angle under normal working conditions and overspeed working conditions, the pitch angle table is set; Collect the real-time pitch motor torque signal, filter the collected pitch motor torque signal, and check the pitch angle table after linear interpolation to obtain the corresponding minimum pitch angle FinePitch; The minimum pitch angle FinePitch is used to control and increase the wind turbine blade angle, reduce the generator speed, and implement the wind turbine generator anti-overspeed control.

2. A wind turbine overspeed prevention control method based on pitch motor torque according to claim 1, characterized in that: Obtain the wind turbine's pitch motor torque and use it to identify the wind turbine's overspeed condition, including: At the preset wind speed, the pitch motor torque is obtained to determine whether the pitch motor torque exceeds the preset range. If it exceeds the preset range, it is determined that the wind turbine is in an overspeed condition at this time. If it does not exceed the preset range, the wind turbine is not in an overspeed condition.

3. The wind turbine overspeed prevention control method based on pitch motor torque according to claim 1, characterized in that: The method of filtering the acquired pitch motor torque signal and looking up the pitch angle table after linear interpolation includes: A low-pass filter is used to remove high-frequency signals from the pitch motor torque signal. The formula is as follows: Where G(s) is the transfer function, ξ is the damping coefficient, ω0 is the natural frequency, and s is the complex frequency; The linear interpolation formula is as follows: Among them, x0 and x1 are the horizontal coordinates of the known points, y0 and y1 are the vertical coordinates of the known points, x is the horizontal coordinate of the unknown point, and y is the vertical coordinate of the unknown point.

4. A wind turbine overspeed prevention control method based on pitch motor torque according to claim 3, characterized in that: The low-pass filter is a second-order low-pass filter.

5. A wind turbine overspeed prevention control system based on pitch motor torque, characterized in that: A method for preventing overspeed control of a wind turbine based on pitch motor torque according to any one of claims 1 to 4 is provided, comprising: A torque acquisition unit, used to obtain the torque of the wind turbine's pitch motor; Identify the working condition unit, which identifies the overspeed condition of the wind turbine based on the torque of the pitch motor; A pitch angle table setting unit sets a pitch angle table corresponding to the pitch motor torque according to the difference in pitch motor torque between normal operating conditions and overspeed operating conditions of the wind turbine; A filtering unit, which filters the collected real-time pitch motor torque signal; The minimum pitch angle acquisition unit obtains the minimum pitch angle FinePitch corresponding to the real-time pitch motor torque by looking up the pitch angle table after linear interpolation; The control unit is used to input the minimum pitch angle FinePitch to control the wind turbine blade angle, reduce the generator speed, and implement the wind turbine generator anti-overspeed control.

6. A wind turbine overspeed prevention control system based on pitch motor torque according to claim 5, characterized in that: The identification working condition unit performs the following operations: It is determined whether the obtained pitch motor torque exceeds a preset range. If it exceeds the preset range, it is determined that the wind turbine is in an overspeed condition at this time. If it does not exceed the preset range, the wind turbine is not in an overspeed condition.

7. The wind turbine overspeed prevention control system based on pitch motor torque according to claim 5, characterized in that: The pitch angle table setting unit performs the following operations: Simulate the rated wind speed of the wind turbine under normal operating conditions and the rated wind speed ±2m / s under normal operating conditions, check the filtered pitch torque of each blade of the wind turbine, take the maximum value of the pitch torque, and record it as A. When the wind turbine pitch torque is A, the corresponding blade pitch angle is the optimal pitch angle of the pitch torque A; Simulate the rated wind speed of the overspeed condition and the rated wind speed ±2m / s for the overspeed condition, check the filtered pitch torque of each blade of the wind turbine, take the minimum value of the pitch torque and record it as B, then check the blade pitch angle, take the average value of the pitch angle and record it as C. When the wind turbine pitch torque is B, the corresponding blade pitch angle is C; The pitch angle table is set according to the corresponding relationship between the pitch torque and pitch angle under normal working conditions and overspeed working conditions.

8. A non-transitory computer-readable medium storing instructions, characterized in that: When the instruction is executed by the processor, the steps of the wind turbine overspeed prevention control method based on pitch motor torque according to any one of claims 1 to 4 are performed.

9. 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 wind turbine overspeed prevention control method based on pitch motor torque according to any one of claims 1 to 4 is implemented.

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