A method and system for identifying a failed pitch actuation of a wind turbine generator

Abstract

The application discloses a method and system for identifying the failure of a wind turbine variable pitch execution, comprising the following steps: acquiring the absolute value of the actual variable pitch rate of each blade in real time; comparing the absolute value of the actual variable pitch rate of each blade with the variable pitch actual rate threshold value of the judgment of a stuck pitch; determining the end of the control variable pitch process or the start of the accumulation time of a stuck pitch according to the size relationship between the absolute value of the actual variable pitch rate of the blade and the variable pitch actual rate threshold value of the judgment of a stuck pitch; when the accumulation time is not greater than the stuck pitch judgment time threshold value, the control process ends; when the accumulation time is greater than the stuck pitch judgment time threshold value, a protection control strategy is sent to the variable pitch system; the actual variable pitch rate is obtained by differentiating the actual variable pitch angle, and the relative size of the actual variable pitch rate of the blade is compared to determine whether the pitch is stuck, so that a method for more quickly identifying the stuck pitch of a single blade is provided, and the limit load of a large component of the unit under the stuck pitch condition can be reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind turbine generator set control, and in particular relates to a method and system for identifying failure of pitch change execution of a wind turbine generator set. Background Art

[0002] The rotor of a horizontal-axis wind turbine absorbs wind energy and rotates, in turn driving the connected generator to generate electricity. The control objectives of the wind turbine vary depending on wind speed. Above rated wind speed, the control objective is to maintain the turbine speed near the rated speed through pitch control, thereby maintaining the turbine output power near the rated power and ensuring that the mechanical and electrical components of the wind turbine operate normally within the designed range.

[0003] In a traditional generator speed-pitch control loop, pitch control commands are transmitted to the pitch actuator, which then performs pitch control. However, if the pitch actuator fails due to component damage or failure, it cannot continuously execute the pitch control command. This situation is very dangerous for the wind turbine because the generator speed cannot be controlled by pitch control. A common solution to this problem is to monitor the actual pitch angle in real time. If it remains unchanged for a period of time, it is considered a stuck pitch. However, this method is affected by wind speed fluctuations. If a stuck pitch cannot be identified in time, it will cause extreme loads on large components of the wind turbine. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a method for identifying failure of pitch control execution of a wind turbine. The present invention obtains the actual pitch rate by differentiating the actual pitch angle, and compares the relative sizes of the actual pitch rates of the three blades to determine whether the blade is stuck. This is a method for faster identification of single-blade stuck blades, thereby reducing the ultimate load of large components of the unit in the event of a stuck blade.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: a method for identifying failure of pitch control execution of a wind turbine generator set, comprising the following steps:

[0006] Obtain the absolute value of each blade's actual pitch rate in real time;

[0007] Compare the absolute value of each blade's actual pitch rate with the actual pitch rate threshold for judging a stuck blade;

[0008] If the absolute value of the actual pitch rate of one blade is not less than the actual pitch rate threshold for judging a stuck pitch, and the absolute values ​​of the actual pitch rates of the other two blades are not greater than the actual pitch rate thresholds for judging a stuck pitch, the pitch control process ends;

[0009] If the absolute value of the actual pitch rate of one of the blades is less than the threshold value of the actual pitch rate for judging the pitch stall, and the absolute values of the actual pitch rates of the other two blades are greater than the threshold value of the actual pitch rate for judging the pitch stall, the accumulated time is started to be accumulated;

[0010] The accumulated time is compared with the threshold value of the time for judging the pitch stall of the blade whose absolute value of the actual pitch rate is less than the threshold value of the actual pitch rate for judging the pitch stall, and when the accumulated time is not greater than the threshold value of the time for judging the pitch stall, the control flow ends; when the accumulated time is greater than the threshold value of the time for judging the pitch stall, a protection control strategy is sent to the pitch system to be executed.

[0011] Further, the absolute value of the actual pitch rate of the blade is the absolute value of the difference between the current actual pitch angle and the previous actual pitch angle divided by the time constant of the actual pitch rate.

[0012] Further, the current actual pitch angle and the previous actual pitch angle are directly obtained based on the sensors of the pitch system.

[0013] Further, the difference between the current actual pitch angle and the previous actual pitch angle is determined based on the current pitch demand angle.

[0014] Further, the threshold value of the actual pitch rate for judging the pitch stall is set to 0.1° / s-0.15° / s, and the pitch stall is triggered when the absolute value of the actual pitch rate of one of the blades is less than the threshold value and the absolute values of the actual pitch rates of the other two blades are greater than the threshold value.

[0015] Further, the time constant of the actual pitch rate is a time constant that is greater than or equal to the calculation period of the controller.

[0016] Further, the protection control strategy is a way of stopping the machine, reducing the speed of the generator, performing yaw control, or fault ride-through.

[0017] Further, based on the concept of the method, a system for identifying the pitch stall of the blades of a wind turbine generator is provided, which comprises a data acquisition module and a judgment and execution module.

[0018] The data acquisition module is used to acquire the absolute value of the actual pitch rate of each blade in real time.

[0019] The judgment and execution module is used to compare the absolute value of the actual pitch rate of each blade with the threshold value of the actual pitch rate for judging the pitch stall; if the absolute value of the actual pitch rate of one of the blades is not less than the threshold value of the actual pitch rate for judging the pitch stall, and the absolute values of the actual pitch rates of the other two blades are not greater than the threshold value of the actual pitch rate for judging the pitch stall, the control flow of the pitch is ended.

[0020] If the absolute value of the actual pitch rate of one of the blades is less than the judged pitch rate threshold value of the pitch-in actual pitch rate, and the absolute values of the actual pitch rates of the other two blades are greater than the judged pitch-in actual pitch rate threshold value, the accumulated time is started to be accumulated;

[0021] The accumulated time is compared with the pitch-in judged time threshold value of the blade pitch-in actual pitch rate absolute value less than the judged pitch-in actual pitch rate threshold value, and when the accumulated time is not greater than the pitch-in judged time threshold value, the control flow is ended; and when the accumulated time is greater than the pitch-in judged time threshold value, a protection control strategy is sent to the pitch system for execution.

[0022] Meanwhile, based on the method, a wind turbine control system can be provided, which adopts the method for identifying the pitch-in execution failure of the wind turbine to identify whether the blades of the wind turbine are pitch-in, and simultaneously executes a control strategy.

[0023] A wind turbine can also be provided, which adopts the wind turbine control system of the present application.

[0024] Compared with the prior art, the present application has at least the following beneficial effects:

[0025] The present application can quickly identify the single-blade pitch-in working condition, so as to quickly execute a protection strategy of the wind turbine, reduce the limit load of the large components of the wind turbine, and achieve the identification of the single-blade pitch-in working condition only by detecting the actual pitch angle without the need of adding new detection hardware. By quickly identifying the pitch-in working condition, the limit load suffered by the wind turbine is reduced, which can help the structural design of the wind turbine, thereby reducing the manufacturing cost. With the development trend of large-capacity wind turbines and large-blade high-tower design, the limit load is reduced, the size of the large components is reduced, and the transportation restrictions are reduced. The quick identification of the pitch-in working condition and the timely shutdown protection can to some extent avoid the occurrence of adverse accidents such as blade tower scanning or wind turbine overturning. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a method flowchart in the actual execution of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] For the convenience of describing the present application, the blades are numbered as blade 1, blade 2 and blade 3, respectively, and the numbering is not used to limit the sequence, and the steps do not need to be executed in sequence in the execution process. The method for identifying the failure of the variable pitch execution of the wind turbine provided by the present application comprises the following steps:

[0029] S1, acquiring a current variable pitch actual angle 1pitch_pos1_c;

[0030] S2, acquiring a previous variable pitch actual angle 1pitch_pos1_p;

[0031] S3, acquiring a variable pitch actual rate conversion time constant pitchrate_t;

[0032] S4, subtracting the previous variable pitch actual angle 1pitch_pos1_p from the current variable pitch actual angle 1pitch_pos1_c to obtain a difference between the front and rear variable pitch actual angles 1;

[0033] S5, dividing the difference between the front and rear variable pitch actual angles 1 obtained in S4 by the variable pitch actual rate conversion time constant pitchrate_t to obtain a variable pitch actual rate of the blade 1pitchrate_1;

[0034] S6, taking an absolute value of the variable pitch actual rate of the blade 1pitchrate_1 to obtain a variable pitch actual rate absolute value of the blade 1pitchrateabs_1;

[0035] S7, acquiring a variable pitch actual rate threshold for judging the jamming of the blade 1pitchratethreshold_1;

[0036] S8, acquiring a current variable pitch actual angle 2pitch_pos2_c;

[0037] S9, acquiring a previous variable pitch actual angle 2pitch_pos2_p;

[0038] S10, subtracting the previous variable pitch actual angle 2pitch_pos2_p from the current variable pitch actual angle 2pitch_pos2_c to obtain a difference between the front and rear variable pitch actual angles 2;

[0039] S11, dividing the difference between the front and rear variable pitch actual angles 2 obtained in S10 by the variable pitch actual rate conversion time constant pitchrate_t to obtain a variable pitch actual rate of the blade 2pitchrate_2;

[0040] S12, taking an absolute value of the variable pitch actual rate of the blade 2pitchrate_2 to obtain a variable pitch actual rate absolute value of the blade 2pitchrateabs_2;

[0041] S13, obtaining a pitch rate threshold value pitchrate threshold_2 for judging blade 2 stuck pitch;

[0042] S14, obtaining a current pitch angle 3 pitch_pos3_c;

[0043] S15, obtaining a previous pitch angle 3 pitch_pos3_p;

[0044] S16, obtaining a difference between the current pitch angle 3 pitch_pos3_c and the previous pitch angle 3 pitch_pos3_p;

[0045] S17, obtaining a pitch rate 3 pitchrate_3 by dividing the difference between the current pitch angle 3 pitch_pos3_c and the previous pitch angle 3 pitch_pos3_p by a pitch rate conversion time constant pitchrate_t;

[0046] Optionally, the current pitch angle and the previous pitch angle can be directly obtained from a sensor of a pitch system.

[0047] The pitch rate conversion time constant in the embodiment is a time constant greater than or equal to a controller calculation period.

[0048] S18, obtaining an absolute value of the pitch rate 3 pitchrate_3 to obtain an absolute value of a pitch rate 3 pitchrateabs_3;

[0049] S19, obtaining a pitch rate threshold value pitchrate threshold_3 for judging blade 3 stuck pitch;

[0050] Generally, the actual pitch rates of three blades are consistent. When the actual pitch rate of one blade is very small and the actual pitch rates of the other two blades are relatively large, the wind turbine blade stuck pitch can be identified, so as to determine the pitch rate threshold value for judging the blade stuck pitch corresponding to each blade. As an example, the pitch rate threshold value for judging the blade stuck pitch can be set to 0.1 degree per second to 0.15 degree per second. When one blade is less than the threshold value and the other two blades are greater than the threshold value, it can be triggered.

[0051] S20, judging whether pitchrateabs_1 is less than pitchrate threshold_1, pitchrateabs_2 is greater than pitchrate threshold_2, and pitchrateabs_3 is greater than pitchrate threshold_3;

[0052] S21, if pitchrateabs_1 is greater than or equal to pitchratethreshold_1 and pitchrateabs_2 is less than or equal to pitchratethreshold_2 and pitchrateabs_3 is less than or equal to pitchratethreshold_3, the control flow ends;

[0053] S22, if pitchrateabs_1 is less than pitchratethreshold_1 and pitchrateabs_2 is greater than pitchratethreshold_2 and pitchrateabs_3 is greater than pitchratethreshold_3, time counting timer1 is started, and timer1 starts from 0;

[0054] S23, a blade 1 stall judgment time threshold pitchthreshold_t is obtained;

[0055] S24, whether timer1 is greater than pitchthreshold_t is judged;

[0056] S25, if timer1 is less than or equal to pitchthreshold_t, the control flow ends;

[0057] S26, if timer1 is greater than pitchthreshold_t, a pitch system executes a shutdown protection;

[0058] S27, whether pitchrateabs_2 is less than pitchratethreshold_2 and pitchrateabs_1 is greater than pitchratethreshold_1 and pitchrateabs_3 is greater than pitchratethreshold_3 is judged;

[0059] S28, if pitchrateabs_2 is greater than or equal to pitchratethreshold_2 and pitchrateabs_1 is less than or equal to pitchratethreshold_1 and pitchrateabs_3 is less than or equal to pitchratethreshold_3, the control flow ends;

[0060] S29, if pitchrateabs_2 is less than pitchratethreshold_2 and pitchrateabs_1 is greater than pitchratethreshold_1 and pitchrateabs_3 is greater than pitchratethreshold_3, then start time counting timer2, timer2 starts from 0;

[0061] S30, if timer2 is greater than pitchthreshold_t, then control flow ends;

[0062] S31, if timer2 is less than or equal to pitchthreshold_t, then control flow ends;

[0063] S32, if timer2 is greater than pitchthreshold_t, then pitch system executes shutdown protection;

[0064] S33, if pitchrateabs_3 is less than pitchratethreshold_3 and pitchrateabs_1 is greater than pitchratethreshold_1 and pitchrateabs_2 is greater than pitchratethreshold_2, then control flow ends;

[0065] S34, if pitchrateabs_3 is greater than or equal to pitchratethreshold_3 and pitchrateabs_1 is less than or equal to pitchratethreshold_1 and pitchrateabs_2 is less than or equal to pitchratethreshold_2, then control flow ends;

[0066] S35, if pitchrateabs_3 is less than pitchratethreshold_3 and pitchrateabs_1 is greater than pitchratethreshold_1 and pitchrateabs_2 is greater than pitchratethreshold_2, then start time counting timer3, timer3 starts from 0;

[0067] S36, if timer3 is greater than pitchthreshold_t, then control flow ends;

[0068] S37, if timer3 is less than or equal to pitchthreshold_t, then control flow ends;

[0069] S38, if timer3 is greater than pitchthreshold_t, the pitch system executes shutdown protection.

[0070] Based on the above embodiments, the pitch system executing shutdown protection according to the application can also be replaced by reducing the generator speed, performing yaw control or fault ride-through; the above methods can be simulated and calculated under the combined load of fault working conditions and extreme wind conditions to determine the replacement method with smaller extreme load.

[0071] The difference between the current pitch actual angle and the previous pitch actual angle in the embodiment can also be determined based on the current pitch demand angle, which can be obtained based on the previous pitch execution and the current unit working condition, so it can also reflect the difference between the actual current pitch actual angle and the previous pitch actual angle.

[0072] Based on the concept of the method, a system for identifying wind turbine blade jamming is provided, comprising a data acquisition module and a judgment and execution module.

[0073] The data acquisition module is used to acquire the absolute value of the actual pitch rate of each blade in real time.

[0074] The judgment and execution module is used to compare the absolute value of the actual pitch rate of each blade with the judgment jamming actual pitch rate threshold value; if the absolute value of the actual pitch rate of one of the blades is not less than its judgment jamming actual pitch rate threshold value, and the absolute values of the actual pitch rates of the other two blades are not greater than their judgment jamming actual pitch rate threshold values, the pitch process is ended.

[0075] If the absolute value of the actual pitch rate of one of the blades is less than its judgment jamming actual pitch rate threshold value, and the absolute values of the actual pitch rates of the other two blades are greater than their judgment jamming actual pitch rate threshold values, the accumulated time is started.

[0076] The accumulated time is compared with the jamming judgment time threshold value of the absolute value of the actual pitch rate of the blade which is less than the judgment jamming actual pitch rate threshold value; when the accumulated time is not greater than the jamming judgment time threshold value, the process is ended; when the accumulated time is greater than the jamming judgment time threshold value, a protection control strategy is sent to the pitch system.

[0077] Meanwhile, based on the method, the application can provide a wind turbine control system, which uses the method for identifying wind turbine pitch execution failure to identify whether the blades of the unit are jammed, and simultaneously executes a control strategy.

[0078] The application can also provide a wind turbine, which uses the above wind turbine control system.

[0079] The above merely illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A method for identifying failure of pitch control execution of a wind turbine, characterized in that: The following steps are involved: Obtain the absolute value of each blade's actual pitch rate in real time; Compare the absolute value of each blade's actual pitch rate with the actual pitch rate threshold for determining a stuck pitch. The actual pitch rate threshold for determining a stuck pitch is set to 0.1° / s to 0.15° / s. A stuck pitch is triggered when one blade is less than the threshold while the other two blades are greater than the threshold. If the absolute value of the actual pitch rate of one blade is not less than the actual pitch rate threshold for judging a stuck pitch, and the absolute values ​​of the actual pitch rates of the other two blades are not greater than the actual pitch rate thresholds for judging a stuck pitch, the pitch control process ends; If the absolute value of the actual pitch rate of one blade is less than the actual pitch rate threshold for judging a stuck pitch, and the absolute values ​​of the actual pitch rates of the other two blades are greater than the actual pitch rate thresholds for judging a stuck pitch, then the time accumulation begins; Comparing the accumulated time with the absolute value of the actual blade pitch rate is less than the pitch sticking judgment time threshold for judging the actual pitch sticking rate threshold. When the accumulated time is not greater than the pitch sticking judgment time threshold, the control process ends; when the accumulated time is greater than the pitch sticking judgment time threshold, the execution protection control strategy is sent to the pitch system.

2. The method for identifying wind turbine pitch control failure according to claim 1, characterized in that: The absolute value of the actual blade pitch rate = the absolute value of the difference between the current actual pitch angle and the previous actual pitch angle / the actual rate conversion time constant.

3. The method for identifying wind turbine pitch control failure according to claim 2, characterized in that: The current actual pitch angle and the previous actual pitch angle are directly acquired based on the sensors of the pitch system.

4. The method for identifying wind turbine pitch control failure according to claim 2, characterized in that: The difference between the current pitch change actual angle and the previous pitch change actual angle is determined based on the current pitch change required angle.

5. The method for identifying wind turbine pitch control failure according to claim 1, characterized in that: The actual pitch rate conversion time constant adopts a time constant that is greater than or equal to the controller calculation period.

6. The method for identifying wind turbine pitch control failure according to claim 1, characterized in that: The protection and control strategies include shutdown protection, reducing generator speed, yaw control or fault ride-through.

7. A system for identifying blade jams in a wind turbine generator set, characterized in that: It includes a data acquisition module and a judgment execution module; The data acquisition module is used to obtain the absolute value of the actual pitch rate of each blade in real time; The judgment execution module is used to compare the relationship between the absolute value of the actual pitch rate of each blade and the actual pitch rate threshold for judging the stuck pitch; the actual pitch rate threshold for judging the stuck pitch is set to 0.1° / s~0.15° / s, and a blade is less than the threshold while the other two blades are greater than the threshold to trigger the stuck pitch; if the absolute value of the actual pitch rate of one blade is not less than the actual pitch rate threshold for judging the stuck pitch, and the absolute values ​​of the actual pitch rates of the other two blades are not greater than the actual pitch rate threshold for judging the stuck pitch, the control pitch process ends; If the absolute value of the actual pitch rate of one blade is less than the actual pitch rate threshold for judging a stuck pitch, and the absolute values ​​of the actual pitch rates of the other two blades are greater than the actual pitch rate thresholds for judging a stuck pitch, then the time accumulation begins; Comparing the accumulated time with the absolute value of the actual blade pitch rate is less than the pitch sticking judgment time threshold for judging the actual pitch sticking rate threshold. When the accumulated time is not greater than the pitch sticking judgment time threshold, the control process ends; when the accumulated time is greater than the pitch sticking judgment time threshold, the execution protection control strategy is sent to the pitch system.

8. A wind turbine generator control system, characterized in that: The method for identifying failure of wind turbine pitch control execution as described in any one of claims 1 to 6 is used to identify whether the blades of the turbine are stuck and to execute a control strategy at the same time.

9. A wind turbine generator set, characterized in that: The wind turbine generator control system according to claim 8 is adopted.

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