A control method, system and storage medium for suppressing the rotational speed fluctuation of a generator

Abstract

The present invention belongs to the field of wind power generation. First, a control method for suppressing the rotational speed fluctuation of a generator is proposed. By calculating the real-time rotational speed of the generator and comparing it with a reference rotational speed, it is determined whether the generator has a rotational speed fluctuation and the severity of the rotational speed fluctuation by comparing the two. The fluctuation conditions are classified into different fluctuation events, and corresponding suppression measures are taken based on different fluctuation events, effectively suppressing the rotational speed fluctuation of the generator and reducing the probability of damage to the unit's drive train. At the same time, the present invention also provides a control system for implementing this control method and a computer-readable storage medium storing an information transfer implementation program.

Description

Technical Field

[0001] The present invention relates to the field of wind power generation, and particularly to a control method, system and storage medium for suppressing the rotational speed fluctuation of a generator. Background Art

[0002] When a wind turbine generates electricity, the main shaft and the wind wheel are in a continuously rotating state. Due to the influence of external factors such as its own natural frequency, the rotational speed of the generator usually fluctuates easily. Long-term fluctuation of the generator rotational speed can easily lead to a reduction in the service life of the elastic support of the generator base, and even directly damage the transmission chain in severe cases. Therefore, how to effectively suppress the rotational speed fluctuation of the generator has become an important task.

[0003] Compared with a direct-drive wind turbine, a doubly-fed wind turbine has a more complex structure due to the presence of a gearbox in the transmission chain, making it more difficult to handle the situation of generator rotational speed fluctuation. Summary of the Invention

[0004] Aiming at the defects in the prior art, the present invention provides a control method for suppressing the rotational speed fluctuation of a generator to solve the technical problem of the lack of effective means to suppress the rotational speed fluctuation of the generator when a wind turbine generates electricity.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] In the first aspect of the present invention, a control method for suppressing the rotational speed fluctuation of a generator is provided, including the following steps:

[0007] Collect the real-time rotational speed of the generator;

[0008] Calculate a comparison reference rotational speed based on the real-time rotational speed of the generator;

[0009] Compare the real-time rotational speed of the generator with the comparison reference rotational speed. If the difference between the real-time rotational speed of the generator and the comparison reference rotational speed is greater than a set threshold, it is determined that the generator has a rotational speed fluctuation, and then start timing and count the number of times of generator rotational speed fluctuation within this timing period;

[0010] Make the following determination based on the number of times of generator rotational speed fluctuation statistically obtained within the same timing period:

[0011] When the number of times of generator rotational speed fluctuation is greater than a first threshold, a rotational speed fluctuation 1 event is triggered; or

[0012] When the number of times of generator rotational speed fluctuation is greater than a second threshold and less than the first threshold, a rotational speed fluctuation 2 event is triggered; where the first threshold is greater than the second threshold;

[0013] And perform the following operations based on the above determination results:

[0014] When the rotational speed fluctuation 1 event is triggered, the pitch is controlled to adjust the rotational speed of the generator; or

[0015] When the rotational speed fluctuation 2 event is triggered, the gain parameter of the damping filter is adjusted.

[0016] Optionally, calculating the comparison reference rotational speed based on the real-time rotational speed of the generator includes:

[0017] Performing multiple sets of filtering processes on the real-time rotational speed of the generator to calculate the comparison reference rotational speed, and satisfying the following formula:

[0018] Y(s) = G 1 (s) * G 2 (s) * G 3 (s) * G 4 (s) * U(s)

[0019] In the formula, Y(s) represents the comparison reference rotational speed SpeedM; G 1 (s) represents a second-order low-pass filter; G 2 (s) represents a tower frequency notch filter; G 3 (s) represents a 3P frequency notch filter; G 4 (s) represents a DriveTrain frequency notch filter; U(s) represents the real-time rotational speed of the generator.

[0020] Optionally, the method for counting the number of rotational speed fluctuations of the generator within the timing period includes:

[0021] When the real-time rotational speed of the generator - the comparison reference rotational speed > the set threshold and then the comparison reference rotational speed - the real-time rotational speed of the generator > the set threshold, a rotational speed fluctuation of the generator is marked; or

[0022] When the comparison reference rotational speed - the real-time rotational speed of the generator > the set threshold and then the real-time rotational speed of the generator - the comparison reference rotational speed > the set threshold, a rotational speed fluctuation of the generator is marked.

[0023] Optionally, the timing duration TD of the timing period satisfies the following formula:

[0024] TD = Max / Hd

[0025] In the formula, Max represents the maximum number of rotational speed fluctuations allowed for the normal operation of the generator, and Hd represents the rotational speed frequency value with the highest amplitude received within the first rotational speed fluctuation marked within the timing period.

[0026] Optionally, when the rotational speed fluctuation 1 event is triggered and the pitch is controlled to adjust the rotational speed of the generator, it further includes:

[0027] When the speed fluctuation 1 event is eliminated and the speed fluctuation 2 event is not triggered, normal control is restored;

[0028] Among them, the condition for the elimination of the speed fluctuation 1 event is:

[0029] After the end of the current timing cycle, there is no generator speed fluctuation for a set time; or

[0030] The next timing cycle is triggered within the set time, and the number of generator speed fluctuations within this next timing cycle is less than the first threshold.

[0031] Optionally, when the speed fluctuation 1 event is triggered, controlling the pitch to adjust the generator speed further includes:

[0032] If the next timing cycle is triggered within the set time after the end of the current timing cycle, and the number of generator speed fluctuations within this next timing cycle is greater than the first threshold, it indicates that the speed fluctuation 1 event is continuously triggered. At this time, control the converter to be de-energized and idling, and reconnect after the speed fluctuation 1 event is eliminated. If the speed fluctuation 1 event is still continuously triggered after the converter is reconnected, control the wind turbine to shut down due to a fault.

[0033] Optionally, when the speed fluctuation 2 event is triggered, adjusting the damping filter gain parameter includes:

[0034] When the speed fluctuation 2 event is eliminated, normal control is restored;

[0035] Among them, the condition for the elimination of the speed fluctuation 2 event is:

[0036] After the end of the current timing cycle, there is no generator speed fluctuation for a set time; or

[0037] The next timing cycle is triggered within the set time, and the number of generator speed fluctuations within this next timing cycle is less than the second threshold.

[0038] Optionally, when the speed fluctuation 2 event is triggered, adjusting the damping filter gain parameter further includes:

[0039] If the next timing cycle is triggered within the set time after the end of the current timing cycle, and the number of generator speed fluctuations within this next timing cycle is greater than the second threshold and less than the first threshold, it indicates that the speed fluctuation 2 event is continuously triggered. At this time, adjust the damping filter resonance frequency parameter.

[0040] In the second aspect of the present invention, a control system for suppressing generator speed fluctuations is provided, including,

[0041] An information acquisition module for acquiring the real-time speed of the generator;

[0042] A data processing module, which is used to calculate a comparison reference speed based on the real-time speed of the generator, and is also used to compare the real-time speed of the generator with the comparison reference speed. If the difference between the real-time speed of the generator and the comparison reference speed is greater than a set threshold, it is determined that the generator has a speed fluctuation, that is, timing starts and the number of speed fluctuations of the generator within this timing period is counted;

[0043] A condition determination module, which is used to make the following determinations based on the number of speed fluctuations of the generator counted within the same timing period:

[0044] When the number of speed fluctuations of the generator is greater than a first threshold, a speed fluctuation 1 event is triggered; or

[0045] When the number of speed fluctuations of the generator is greater than a second threshold and less than the first threshold, a speed fluctuation 2 event is triggered; wherein, the first threshold is greater than the second threshold;

[0046] A control and adjustment module, which is used to perform the following operations based on the determination result of the condition determination module:

[0047] When the speed fluctuation 1 event is triggered, control the pitch to adjust the generator speed; or

[0048] When the speed fluctuation 2 event is triggered, adjust the damping filter gain parameter.

[0049] In the third aspect of the present invention, a computer-readable storage medium is provided. An implementation program for information transmission is stored on the computer-readable storage medium. When the program is executed by a processor, the steps of a control method for suppressing generator speed fluctuations as described above are implemented.

[0050] As can be seen from the above technical solutions, the beneficial effects of the present invention are:

[0051] The present invention first proposes a control method for suppressing generator speed fluctuations. By calculating a comparison reference speed through the real-time speed of the generator, and comparing the two to determine whether the generator has a speed fluctuation and the severity of the speed fluctuation, the fluctuation situation is classified into different fluctuation events, and corresponding suppression measures are taken based on different fluctuation events, effectively suppressing the generator speed fluctuation and reducing the probability of damage to the unit transmission chain. At the same time, the present invention also provides a control system for implementing this control method and a computer-readable storage medium storing an information transmission implementation program. Specific embodiments

[0052] The embodiments of the technical solutions of the present invention will be described in detail below. The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0053] The present invention first provides a control method for suppressing the rotational speed fluctuation of a generator, which is implemented by combining a PLC controller and an industrial computer. Among them, the functions of the PLC controller are as follows: 1) monitoring rotational speed fluctuation events, 2) controlling the torque output of the converter and the rotational speed of the generator; the function of the industrial computer is to semi-real-time calculate the current rotational speed frequency and amplitude, and the specific description is as follows:

[0054] When the unit is connected to the grid and generating electricity, the real-time rotational speed of the generator collected by the encoder is transmitted to the PLC in real time. The PLC monitors and judges the rotational speed fluctuation of the generator in real time, and at the same time transmits it to the industrial computer through fieldbus communication for FFT calculation in real time; after the industrial computer calculates, the calculation result (the rotational speed frequency value Hd with the highest amplitude) is transmitted to the PLC through fieldbus communication again; the PLC adjusts the torque output and rotational speed control according to the calculation result of the industrial computer and the monitoring result of the rotational speed fluctuation event of the PLC.

[0055] Specifically, the PLC generator rotational speed detection specifically includes the following steps:

[0056] S1. Collect the real-time rotational speed of the generator;

[0057] S2. Calculate the comparison reference rotational speed based on the real-time rotational speed of the generator;

[0058] Specifically, multiple groups of filtering processes are performed on the real-time rotational speed of the generator to calculate the comparison reference rotational speed, and the following formula is satisfied:

[0059] Y(s) = G 1 (s)*G 2 (s)*G 3 (s)*G 4 (s)*U(s)

[0060] In the formula, Y(s) represents the comparison reference rotational speed SpeedM; G 1 (s) represents a second-order low-pass filter; G 2 (s) represents a tower frequency notch filter; G 3 (s) represents a 3P frequency notch filter; G 4 (s) represents a DirveTrain frequency notch filter; U(s) represents the real-time rotational speed of the generator;

[0061] S3. Compare the real-time rotational speed of the generator with the comparison reference rotational speed. If the difference (taking the absolute value) between the real-time rotational speed of the generator and the comparison reference rotational speed is greater than the set threshold, it is determined that the generator has a rotational speed fluctuation, that is, start timing and count the number of rotational speed fluctuations of the generator within this timing period;

[0062] In one embodiment, the counting of the number of rotational speed fluctuations of the generator within this timing period includes:

[0063] When the real-time speed of the generator - the reference speed for comparison > the set threshold and then the reference speed for comparison - the real-time speed of the generator > the set threshold, mark a generator speed fluctuation once; or

[0064] When the reference speed for comparison - the real-time speed of the generator > the set threshold and then the real-time speed of the generator - the reference speed for comparison > the set threshold, mark a generator speed fluctuation once;

[0065] Wherein, the timing duration TD of the timing period satisfies the following formula:

[0066] TD = Max / Hd

[0067] In the formula, Max represents the maximum number of speed fluctuations allowed for the normal operation of the generator, and Hd represents the highest speed frequency value received within the first speed fluctuation marked during this timing period;

[0068] S4. Make the following judgments based on the number of generator speed fluctuations statistically obtained within the same timing period:

[0069] When the number of generator speed fluctuations > the first threshold, the speed fluctuation 1 event is triggered; or

[0070] When the number of generator speed fluctuations > the second threshold and < the first threshold, the speed fluctuation 2 event is triggered; where the first threshold > the second threshold;

[0071] In one embodiment, if it is determined that the number of fluctuations > Max, report the speed fluctuation 1 event (that is, consider the fluctuation situation very serious), if the number of fluctuations < Max, eliminate the speed fluctuation 1 event; if it is determined that the number of fluctuations > Max - K, where K represents the offset value and Max - K represents the warning value of the number of speed fluctuations during the normal operation of the generator within the timing duration, report the speed fluctuation 2 event (that is, consider the fluctuation situation not very serious), if the number of fluctuations < Max - K, eliminate the speed fluctuation 2 event.

[0072] Furthermore, the control of the PLC includes the following two situations:

[0073] Situation 1: After the unit is connected to the grid and generating electricity, the PLC starts to monitor the generator speed fluctuation. If the speed fluctuation event 1 is triggered, the PLC controls the pitch to adjust the generator speed; if the speed fluctuation 1 event is eliminated and the speed fluctuation 2 event is not triggered, resume normal control. If the speed fluctuation 1 event continues to be triggered, the PLC controls the converter to be de-energized and idling; if the speed fluctuation 1 event is eliminated, the PLC controls the converter to be reconnected to the grid and resume normal control; if the speed fluctuation 1 event continues to be triggered, the PLC reports a fault and shuts down the unit.

[0074] Among them, the determination condition for the elimination of the speed fluctuation 1 event is:

[0075] There is no fluctuation in the generator speed for a set time after the end of the current timing cycle; or

[0076] The next timing cycle is triggered within the set time, and the number of fluctuations in the generator speed within the next timing cycle is less than the first threshold;

[0077] The determination condition for continuous triggering of the speed fluctuation 1 event is:

[0078] If the next timing cycle is triggered within the set time after the end of the current timing cycle, and the number of fluctuations in the generator speed within the next timing cycle is greater than the first threshold, it indicates continuous triggering of the speed fluctuation 1 event.

[0079] In the second case, after the unit is connected to the grid and generating electricity, the PLC starts to monitor the generator speed fluctuation. If the speed fluctuation 1 event is not triggered and the speed fluctuation 2 event is triggered, the PLC adjusts the gain parameter of the DTD (damping filter) to regulate the output torque to suppress the speed fluctuation; if the speed fluctuation 2 event is eliminated and normal control is restored, and if the difference in the comparison value between the fluctuation frequency feedback by the industrial computer and the resonance frequency parameter of the current second-order drive chain damping filter DTD is small, the PLC continues to adjust the DTD gain parameter; if the speed fluctuation 2 event continues to be triggered and the difference in the comparison value between the fluctuation frequency feedback by the industrial computer and the resonance frequency parameter of the current second-order drive chain damping filter DTD is large, the PLC adjusts the resonance frequency parameter of the DTD to regulate the phase difference between the output torque and the generator speed to suppress the speed fluctuation.

[0080] Among them, the determination condition for the elimination of the speed fluctuation 2 event is:

[0081] There is no fluctuation in the generator speed for a set time after the end of the current timing cycle; or

[0082] The next timing cycle is triggered within the set time, and the number of fluctuations in the generator speed within the next timing cycle is less than the second threshold;

[0083] The determination condition for continuous triggering of the speed fluctuation 2 event is:

[0084] If the next timing cycle is triggered within the set time after the end of the current timing cycle, and the number of fluctuations in the generator speed within the next timing cycle is greater than the second threshold and less than the first threshold, it indicates continuous triggering of the speed fluctuation 2 event.

[0085] The present invention also provides a control system for suppressing generator speed fluctuations for implementing a control method for suppressing generator speed fluctuations, including an information acquisition module, a data processing module, a condition determination module, and a control adjustment module; among them,

[0086] The information acquisition module is used to acquire the real-time speed of the generator;

[0087] The data processing module is used to calculate the comparison reference speed based on the real-time speed of the generator, and is also used to compare the real-time speed of the generator with the comparison reference speed. If the difference between the real-time speed of the generator and the comparison reference speed is greater than the set threshold, it is determined that the generator has a speed fluctuation, that is, the timing starts and the number of speed fluctuations of the generator within this timing period is counted;

[0088] The condition determination module is used to make the following determinations based on the number of generator speed fluctuations statistically obtained within the same timing period:

[0089] When the number of generator speed fluctuations is greater than the first threshold, the speed fluctuation 1 event is triggered; or

[0090] When the number of generator speed fluctuations is greater than the second threshold and less than the first threshold, the speed fluctuation 2 event is triggered; where the first threshold is greater than the second threshold;

[0091] The control and regulation module is used to perform the following operations based on the determination result of the condition determination module:

[0092] When the speed fluctuation 1 event is triggered, control the pitch to regulate the generator speed; or

[0093] When the speed fluctuation 2 event is triggered, adjust the damping filter gain parameter.

[0094] The present invention also provides a computer-readable storage medium, on which an implementation program for information transmission is stored. When the program is executed by a processor, the steps of a control method for suppressing generator speed fluctuations as described above are implemented.

[0095] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A control method for suppressing the rotational speed fluctuation of a generator, characterized in that, it includes the following steps: Collect the real-time rotational speed of the generator; Calculate a comparison reference rotational speed based on the real-time rotational speed of the generator; including performing multiple sets of filtering processing on the real-time rotational speed of the generator to calculate the comparison reference rotational speed, and satisfying the following formula: Y(s) = G 1 (s) * G 2 (s) * G 3 (s) * G 4 (s) * U(s) Wherein, Y(s) represents the reference speed SpeedM; G 1 (s) represents a second-order low-pass filter; G 2 (s) represents a tower frequency notch; G 3 (s) represents a 3P frequency notch; G 4 (s) represents a DriveTrain frequency notch; U(s) represents the real-time speed of the generator; Compare the real-time rotational speed of the generator with the comparison reference rotational speed. If the difference between the real-time rotational speed of the generator and the comparison reference rotational speed is greater than a set threshold, it is determined that the generator has a rotational speed fluctuation, that is, start timing and count the number of rotational speed fluctuations of the generator within the timing period; Among them, the timing duration TD of the timing period satisfies the following formula: TD = Max / Hd In the formula, Max represents the maximum number of rotational speed fluctuations allowed for the normal operation of the generator, and Hd represents the rotational speed frequency value with the highest amplitude received within the first rotational speed fluctuation marked within this timing period; Make the following determination based on the number of rotational speed fluctuations of the generator statistically obtained within the same timing period: When the number of rotational speed fluctuations of the generator is greater than the first threshold, the rotational speed fluctuation 1 event is triggered; or When the number of rotational speed fluctuations of the generator is greater than the second threshold and less than the first threshold, the rotational speed fluctuation 2 event is triggered; where the first threshold is greater than the second threshold; And perform the following operations based on the above determination results: When the rotational speed fluctuation 1 event is triggered, control the pitch to adjust the rotational speed of the generator; or When the rotational speed fluctuation 2 event is triggered, adjust the damping filter gain parameter.

2. The control method for suppressing the rotational speed fluctuation of a generator according to claim 1, characterized in that, the step of counting the number of rotational speed fluctuations of the generator within the statistical timing period includes: When the real-time rotational speed of the generator - the comparison reference rotational speed > the set threshold and then the comparison reference rotational speed - the real-time rotational speed of the generator > the set threshold, mark a rotational speed fluctuation of the generator; or When the comparison reference rotational speed - the real-time rotational speed of the generator > the set threshold and then the real-time rotational speed of the generator - the comparison reference rotational speed > the set threshold, mark a rotational speed fluctuation of the generator.

3. The control method for suppressing the rotational speed fluctuation of a generator according to claim 1, characterized in that, when the rotational speed fluctuation 1 event is triggered, controlling the pitch to adjust the rotational speed of the generator further includes: When the rotational speed fluctuation 1 event is eliminated and the rotational speed fluctuation 2 event is not triggered, resume normal control; Among them, the condition for eliminating the rotational speed fluctuation 1 event is: No rotational speed fluctuation of the generator occurs for a set time after the end of the current timing period; or The next timing period is triggered within the set time, and the number of rotational speed fluctuations of the generator within the next timing period is less than the first threshold.

4. The control method for suppressing the rotational speed fluctuation of a generator according to claim 3, characterized in that, when the rotational speed fluctuation 1 event is triggered, controlling the pitch to adjust the rotational speed of the generator further includes: Trigger the next timing cycle within a set time after the end of the current timing cycle. If the number of fluctuations in the generator speed within the next timing cycle is greater than the first threshold, it indicates that the speed fluctuation 1 event is continuously triggered. At this time, control the converter to be disconnected from the grid and idling, and reconnect to the grid after the speed fluctuation 1 event is eliminated. If the speed fluctuation 1 event is still continuously triggered after the converter reconnects to the grid, control the wind turbine to shut down due to a fault.

5. A control method for suppressing generator speed fluctuations according to claim 1, characterized in that, when the speed fluctuation 2 event is triggered, adjust the damping filter gain parameter, including: when the speed fluctuation 2 event is eliminated, resume normal control; wherein, the condition for eliminating the speed fluctuation 2 event is: no generator speed fluctuation occurs for a continuous set time after the end of the current timing cycle; or trigger the next timing cycle within the set time, and the number of fluctuations in the generator speed within the next timing cycle is less than the second threshold.

6. A control method for suppressing generator speed fluctuations according to claim 5, characterized in that, when the speed fluctuation 2 event is triggered, adjusting the damping filter gain parameter further includes: trigger the next timing cycle within the set time after the end of the current timing cycle, and the number of fluctuations in the generator speed within the next timing cycle is greater than the second threshold and less than the first threshold, indicating that the speed fluctuation 2 event is continuously triggered. At this time, adjust the damping filter resonance frequency parameter.

7. A control system for suppressing generator speed fluctuations, characterized in that, including, an information acquisition module for acquiring the real-time speed of the generator; a data processing module for calculating a comparison reference speed based on the real-time speed of the generator, and also for comparing the real-time speed of the generator with the comparison reference speed. If the difference between the real-time speed of the generator and the comparison reference speed is greater than the set threshold, it is determined that the generator has a speed fluctuation, and then start timing and counting the number of fluctuations in the generator speed within the timing cycle; wherein, calculating the comparison reference speed from the real-time speed of the generator includes calculating the comparison reference speed by performing multiple sets of filtering processes on the real-time speed of the generator, and satisfying the following formula: Y(s) = G 1 (s) * G 2 (s) * G 3 (s) * G 4 (s) * U(s) Wherein, Y(s) represents the reference speed SpeedM; G 1 (s) represents a second-order low-pass filter; G 2 (s) represents a tower frequency notch; G 3 (s) represents a 3P frequency notch; G 4 (s) represents a DriveTrain frequency notch; U(s) represents the real-time speed of the generator; The timing duration TD of the timing cycle satisfies the following formula: TD = Max / Hd In the formula, Max represents the maximum number of speed fluctuations allowed for the normal operation of the generator, and Hd represents the highest speed frequency value received within the first speed fluctuation marked within the timing cycle; a condition determination module for making the following determinations based on the number of fluctuations in the generator speed statistically obtained within the same timing cycle: when the number of fluctuations in the generator speed is greater than the first threshold, the speed fluctuation 1 event is triggered; or when the number of fluctuations in the generator speed is greater than the second threshold and less than the first threshold, the speed fluctuation 2 event is triggered; wherein, the first threshold is greater than the second threshold; a control and adjustment module for performing the following operations based on the determination result of the condition determination module: when the speed fluctuation 1 event is triggered, control the pitch to adjust the generator speed; or when the speed fluctuation 2 event is triggered, adjust the damping filter gain parameter.

8. A computer-readable storage medium, characterized in that, an implementation program for information transmission is stored on the computer-readable storage medium, and when the program is executed by a processor, the steps of a control method for suppressing the rotational speed fluctuation of a generator as described in any one of claims 1-6 are implemented.