Wind turbine rotor speed determination method, variable pitch control method and controller

Abstract

Disclosed are a method for determining the rotating speed of a wind turbine impeller, a variable pitch control method and a controller. The method for determining the rotating speed of the wind turbine impeller comprises: in response to a communication interruption between a variable pitch controller and a main controller of the wind turbine during normal operation of a variable pitch system, sampling torque data of a variable pitch motor; obtaining a frequency spectrum of the torque data of the variable pitch motor by performing a frequency domain transformation on the sampled torque data; and determining the rotating speed of the wind turbine impeller based on the obtained frequency spectrum. According to the present disclosure, the rotating speed of the wind turbine impeller can be determined quickly and accurately, which can avoid loss of power generation on the one hand and ensure normal operation of the overspeed protection of the wind turbine on the other hand.

Description

Technical Field

[0001] This disclosure generally relates to the field of wind power generation technology, and more specifically, to a method for determining the rotor speed of a wind turbine, a pitch control method, and a controller. Background Technology

[0002] During wind turbine operation, the primary factor significantly impacting wind turbine safety is the rotor speed exceeding the generator's design safety threshold. When the rotor speed exceeds this threshold, it leads to excessive vibration, excessive loads on various components, and potentially serious damage to major parts. It can also cause generator overspeeding or even runaway. In such situations, the wind turbine's pitch system must immediately and rapidly adjust the pitch angle of the three blades to a safe stopping position to reduce the rotor speed. This effectively reduces the load on the turbine's components, protecting the overall safety of the wind turbine and preventing significant losses.

[0003] When communication between the wind turbine's main control system and pitch system is interrupted, the pitch system cannot obtain data such as rotor speed and wind speed. If the pitch system operates blindly at this time, it could potentially cause the wind turbine to overspeed. Therefore, to protect the wind turbine's safety, a feathering shutdown will be triggered, causing the blades to retract to a safe position (e.g., 89 degrees). However, in some cases, the slip ring communication between the wind turbine's main control system and pitch system is only interrupted for a short time, and slip ring malfunctions or electromagnetic interference are determined by the slip ring's rotational structure, making these abnormalities difficult to eliminate. Therefore, if feathering shutdown is triggered every time communication between the wind turbine's main control system and pitch system is interrupted, it will result in significant power generation losses. Summary of the Invention

[0004] Therefore, the embodiments of this disclosure provide a method for determining the rotor speed of a wind turbine, a pitch control method, and a controller. When communication between the main control system and the pitch system of the wind turbine is interrupted, the accurate rotor speed can be obtained by frequency domain transformation of the torque data of the pitch motor. This serves as the basis for redundant operation of the pitch system, thereby avoiding power generation loss and ensuring the normal operation of the overspeed protection of the wind turbine.

[0005] In one general aspect, a method for determining the rotor speed of a wind turbine is provided, the method comprising: sampling torque data of a pitch motor in response to a communication interruption between the pitch controller and the main controller of the wind turbine during normal operation of the pitch system; obtaining the spectrum of the pitch motor torque data by performing frequency domain transformation on the sampled torque data; and determining the rotor speed of the wind turbine based on the obtained spectrum.

[0006] Optionally, the impeller speed determination method further includes setting the number of sampling points and the sampling frequency before sampling the torque data of the pitch motor.

[0007] Optionally, in response to the number of torque data samples reaching the set number of sampling points, or in response to the sampling duration of torque data reaching the preset duration, the sampled torque data is subjected to frequency domain transformation.

[0008] Optionally, the frequency domain transformation includes a fast Fourier transform.

[0009] Optionally, the step of determining the rotor speed of the wind turbine based on the obtained spectrum includes: determining the rotor speed of the wind turbine based on the frequency value corresponding to the maximum signal strength in the obtained spectrum.

[0010] Optionally, the step of determining the rotor speed of the wind turbine based on the obtained spectrum further includes: in response to the frequency value corresponding to the maximum signal strength in the obtained spectrum being less than a preset frequency threshold, determining the product of the frequency value and 60 as the rotor speed of the wind turbine.

[0011] Optionally, the steps of sampling the torque data of the pitch motor, obtaining the spectrum of the torque data of the pitch motor, and determining the rotor speed of the wind turbine can be performed periodically.

[0012] In another general aspect, a pitch control method for a wind turbine is provided, wherein the pitch control method: in response to a communication interruption between the pitch controller and the main controller of the wind turbine during normal operation of the pitch system, the pitch system is controlled to enter a redundant operation mode; in the redundant operation mode, for each pitch motor of the wind turbine, the rotor speed determination method described above is executed in a polling manner to determine the rotor speed of the wind turbine; in response to the rotor speed determined for each pitch motor being consistently less than or equal to a preset speed threshold within a preset time period, the pitch system is controlled to exit the redundant operation mode.

[0013] Optionally, the pitch control method further includes: in response to the restoration of normal communication between the pitch controller and the main controller of the wind turbine within a preset time period, controlling the pitch system to exit the redundant operation mode.

[0014] Optionally, the pitch control method further includes: in response to the pitch system exiting the redundant operation mode, the communication between the pitch controller and the main controller of the wind turbine is restored to normal, and the rotor speed obtained from the main controller is less than or equal to a preset speed threshold, thereby controlling the pitch system to operate normally; in response to the pitch system exiting the redundant operation mode, the communication between the pitch controller and the main controller of the wind turbine is still interrupted, or the rotor speed obtained from the main controller is greater than the preset speed threshold, thereby triggering a fault shutdown of the wind turbine.

[0015] In another general aspect, a computer-readable storage medium is provided that stores a computer program, which, when executed by a processor, implements the impeller speed determination method or the pitch control method as described above.

[0016] In another general aspect, a controller is provided, characterized in that the controller includes: a processor; and a memory storing a computer program, which, when executed by the processor, implements the impeller speed determination method as described above or the pitch control method as described above.

[0017] In another general aspect, a wind turbine is provided, characterized in that the wind turbine includes the controller described above.

[0018] The method for determining the rotor speed, the pitch control method, and the controller for wind turbines according to embodiments of this disclosure can quickly and accurately determine the rotor speed by performing frequency domain transformation on the torque data of the pitch motor when communication between the main control system and the pitch system of the wind turbine is interrupted. This serves as the basis for redundant operation of the pitch system, which can avoid power generation loss and ensure the normal operation of the overspeed protection of the wind turbine. Attached Figure Description

[0019] The above and other objects and features of the embodiments of this disclosure will become clearer from the following description taken in conjunction with the accompanying drawings illustrating the embodiments, wherein:

[0020] Figure 1 This is a diagram showing the torque curve of the pitch motor in a pitch system with a toothed belt drive.

[0021] Figure 2 This is a diagram showing the torque curve of the pitch motor in a geared pitch system;

[0022] Figure 3 It is a diagram showing the torque curve of the pitch motor of the wind turbine unit when the pitch is adjusted in strong winds;

[0023] Figure 4 This is a diagram showing the torque curve of the pitch motor when the pitch system of the wind turbine is maintained at 0 speed.

[0024] Figure 5 This is a flowchart illustrating a method for determining the rotor speed of a wind turbine according to an embodiment of the present disclosure;

[0025] Figure 6 It shows that by... Figure 4 The graph shows the spectrum obtained by performing FFT on the torque data of the pitch motor.

[0026] Figure 7It is a torque curve diagram showing the pitch motor under complex operating conditions;

[0027] Figure 8 It shows that by... Figure 7 The graph shows the spectrum obtained by performing FFT on the torque data of the pitch motor.

[0028] Figure 9 This is a flowchart illustrating a pitch control method for a wind turbine according to an embodiment of the present disclosure;

[0029] Figure 10 This is a block diagram illustrating a controller according to an embodiment of the present disclosure;

[0030] Figure 11 This is a control topology diagram of the pitch system of a wind turbine according to an embodiment of the present disclosure. Detailed Implementation

[0031] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent upon understanding this disclosure. For example, the order of operations described herein is merely illustrative and is not limited to those orders set forth herein, but may be changed as will become clear upon understanding this disclosure, except for operations that must occur in a specific order. Furthermore, for clarity and conciseness, descriptions of features known in the art may be omitted.

[0032] Currently, the generator speed (i.e., rotor speed) of wind turbines is generally acquired by the main controller of the wind turbine, and the control signals from the main controller to the pitch system are mainly transmitted through slip rings. For communication failures caused by slip ring interference, only feathering shutdown can be performed to ensure the safety of the wind turbine. The reasons for this operation and its shortcomings are described below.

[0033] First, pitch control systems typically cannot directly acquire wind speed data and cannot determine the current wind speed magnitude. Since wind speed is transient, the pitch control system must not operate blindly after a communication failure, otherwise it could easily jeopardize the safety of the wind turbine. Second, pitch control systems typically cannot directly detect generator speed. Therefore, after a communication failure, the pitch control system often cannot obtain the rotor speed. In this situation, the pitch control system must not operate blindly, otherwise it could easily jeopardize the safety of the wind turbine.

[0034] Figure 1 This is a diagram showing the torque curve of the pitch motor in a toothed belt driven pitch system. Figure 1 In the diagram, the horizontal axis represents the time value, and the vertical axis represents the torque amplitude. From... Figure 1It can be seen that under normal pitch control, the torques of the three pitch motors all exhibit sinusoidal fluctuations, with a phase difference of 120 degrees. This indicates that the torque values ​​of the pitch motors change periodically with the rotation of the impeller. Figure 2 This is a diagram showing the torque curve of the pitch motor in a geared pitch system. Figure 2 In the diagram, the horizontal axis represents the time value, and the vertical axis represents the torque amplitude. From... Figure 2 It can be seen that under normal pitch control conditions, the torque of the three pitch motors also exhibits a sinusoidal periodic change.

[0035] Analysis of the forces acting on wind turbine blades reveals that the torque exerted on each blade varies with its azimuth angle during each impeller rotation cycle. Corresponding to the constant-speed motion of a pitch motor, the blade torque equals the output torque of the pitch motor. That is, the blade torque corresponds to the pitch motor torque. Therefore, the impeller speed can be calculated based on the sinusoidal variation of the pitch motor torque data.

[0036] A method has been proposed to calculate the period of sinusoidal variation based on the sinusoidal variation of the pitch motor's torque data, and then determine the impeller speed. However, in actual calculations, such as... Figure 1 As shown, the torque data contains significant spikes, such as... Figure 2 As shown, the torque data does not exhibit a standard sinusoidal variation. In... Figure 1 and Figure 2 In the cases shown, using a standard sine wave to calculate the torque data's variation period will lead to a decrease in calculation accuracy. Even for... Figure 2 As shown, using a standard sinusoidal variation cannot effectively calculate the period of torque data variation.

[0037] On the other hand, the above method is only applicable to wind turbines operating in high winds and with continuous blade pitch adjustment. However, when the pitch system is held at 0 speed, the torque data does not change in a standard sinusoidal manner and exhibits some abrupt fluctuations. Even with added filtering to the torque data, it is impossible to filter it into a standard sinusoidal signal. In this case, the above method is no longer suitable for determining the impeller speed.

[0038] Figure 3 This is a diagram showing the torque curve of the pitch motor of a wind turbine during high wind pitch control. Figure 3 In the diagram, the horizontal axis represents the time value, and the vertical axis represents the magnitude of the torque. (In a similar context...) Figure 3 When the torque data fluctuates, the torque curve changes in a manner close to a sine wave. Therefore, the torque curve can be smoothed by filtering, and the torque change period can be calculated based on the characteristics of the sine wave. Figure 4This is a diagram showing the torque curve of the pitch motor when the pitch system of the wind turbine is maintained at 0 speed. Figure 4 In the diagram, the horizontal axis represents the time value, and the vertical axis represents the magnitude of the torque. For example... Figure 4 As shown, the torque curves of the three pitch motors exhibit irregular variations, with varying degrees of fluctuation or abrupt changes. For example, at position 613, pitch motor 1 experiences a sudden torque change. Furthermore, the durations of positive and negative fluctuations in the torque data of the three pitch motors are all different. In this situation, using a standard three-phase sine curve to calculate the torque change period can easily lead to calculation errors.

[0039] In view of the shortcomings of the above methods, this disclosure proposes a method for determining the impeller speed by performing frequency domain transformation on the torque data of a pitch motor, calculating the torque data change period, and then determining the impeller speed. According to the embodiments of this disclosure, the impeller speed determination method abandons existing time-threshold period detection methods (such as calculating sinusoidal phase, calculating pulse period, etc.), and instead uses frequency domain transformation to calculate the torque change period. Its advantages are that it does not require smoothing processing such as filtering of the torque data, and is unaffected by the torque data waveform; the torque change period can be directly calculated, thereby determining the impeller speed, improving the accuracy of the calculation and the uniformity of the method.

[0040] The following reference Figures 5 to 11 The present disclosure provides a detailed description of a method for determining the rotor speed, a pitch control method, and a controller for a wind turbine generator according to embodiments thereof.

[0041] Figure 5 This is a flowchart illustrating a method for determining the rotor speed of a wind turbine according to an embodiment of the present disclosure. The method for determining the rotor speed of a wind turbine according to an embodiment of the present disclosure can be executed by the pitch controller of the wind turbine or by any dedicated controller installed in the wind turbine.

[0042] Reference Figure 5 In step S501, in response to a communication interruption between the pitch controller and the main controller of the wind turbine during normal operation of the pitch system, the torque data of the pitch motor is sampled. Optionally, the number of sampling points and the sampling frequency can be set before sampling the torque data of the pitch motor.

[0043] In step S502, the frequency spectrum of the pitch motor's torque data is obtained by performing a frequency domain transformation on the sampled torque data. According to embodiments of this disclosure, the frequency domain transformation can be performed on the sampled torque data when the number of torque data samples reaches a set number of sampling points, or when the sampling duration of the torque data reaches a preset duration. The number of sampling points and the sampling frequency can be set by those skilled in the art according to the frequency domain transformation method used, and this disclosure does not impose any limitations on them. Furthermore, the preset duration can also be set by those skilled in the art according to actual needs, and this disclosure does not impose any limitations on it. According to embodiments of this disclosure, the frequency domain transformation may include a Fast Fourier Transform (FFT). However, this disclosure is not limited to this, and other frequency domain transformation methods can also be used, such as, but not limited to, the Discrete Fourier Transform.

[0044] In step S503, the rotor speed of the wind turbine is determined based on the obtained spectrum. Specifically, the rotor speed of the wind turbine can be determined based on the frequency value corresponding to the maximum signal strength in the obtained spectrum. Here, since the spectrum calculated by, for example, FFT is symmetrical, when determining the maximum signal strength in the spectrum, data with frequency values ​​less than 0 can be removed from the spectrum first (i.e., the left half of the symmetrical spectrum).

[0045] According to embodiments of this disclosure, since frequency and period are reciprocals, after obtaining the frequency value corresponding to the maximum signal strength in the spectrum, the reciprocal of the obtained frequency value (f) can be taken to determine the variation period (T) of the torque data. The variation period of the torque data determined in this way is unaffected by the fluctuation pattern of the torque curve and external interference (e.g., glitches). Furthermore, when the frequency value corresponding to the maximum signal strength in the obtained spectrum is less than a preset frequency threshold, the product of the frequency value corresponding to the maximum signal strength and 60 can be determined as the rotor speed of the wind turbine, i.e., speed n = 60f = 60 / T. Here, the preset frequency threshold can be, for example, 0.25Hz, but this disclosure is not limited to this. The preset frequency threshold can be less than 0.25Hz.

[0046] Alternatively, since the rotor speed of the wind turbine needs to be continuously determined when the communication between the pitch controller and the main controller of the wind turbine is interrupted, the steps S501, S502 and S503 described above can be executed periodically.

[0047] The method for determining the rotor speed of a wind turbine according to the embodiments of this disclosure can quickly and accurately determine the rotor speed by performing frequency domain transformation on the torque data of the pitch motor when the communication between the main control system and the pitch system of the wind turbine is interrupted. This serves as the basis for the redundant operation of the pitch system, which can avoid the loss of power generation and ensure the normal operation of the overspeed protection of the wind turbine.

[0048] Figure 6 It shows that by... Figure 4 The graph shows the spectrum obtained by performing an FFT on the torque data of the pitch motor.

[0049] exist Figure 6 In the diagram, the horizontal axis represents frequency, and the vertical axis represents signal strength. For example... Figure 6 As shown, the maximum signal strength in the spectrum is 8080.90496124, while the corresponding frequency value is 0.079, which is less than the preset frequency threshold (e.g., but not limited to 0.25Hz). Therefore, the rotor speed of the wind turbine can be calculated to be 60 * 0.079 = 4.74 rpm.

[0050] Figure 7 This is a torque curve diagram showing the pitch motor under complex operating conditions. Figure 8 It shows that by... Figure 7 The image shows a spectrum obtained by performing an FFT on the torque data of the pitch motor. Figure 7 In the diagram, the horizontal axis represents the time value, and the vertical axis represents the torque amplitude. Figure 8 In the diagram, the horizontal axis represents frequency, and the vertical axis represents signal strength.

[0051] Reference Figure 7 The torque data of a pitch motor has a very complex waveform, containing both low-frequency and high-frequency signals. For such torque data, it is impossible to determine the impeller speed using the sinusoidal variation law of the pitch motor's torque data. However, referring to... Figure 8 The maximum signal strength in the spectrum can be determined to be 2370.57699168, and the corresponding frequency value is 0.1984, which is less than the preset frequency threshold (e.g., but not limited to 0.25Hz). Therefore, the rotor speed of the wind turbine can be calculated to be 60 * 0.1984 = 11.9 rpm.

[0052] According to embodiments of this disclosure, the autocorrelation of the torque data of the pitch motor can also be calculated to determine the strength of the periodicity of torque changes. The method for calculating the autocorrelation coefficient is well known to those skilled in the art and will not be elaborated upon here. The closer the autocorrelation coefficient is to 1, the stronger the periodicity of the torque changes. For example, for a pitch motor... Figure 4 The torque data of the pitch motor shown can be calculated to have an autocorrelation coefficient of approximately 0.5619, indicating strong periodicity in the torque data variation. However, for... Figure 7 The torque data of the pitch motor shown can be calculated to have an autocorrelation coefficient of approximately -0.003, indicating that the periodicity of the torque data variation is relatively weak.

[0053] Figure 9This is a flowchart illustrating a pitch control method for a wind turbine according to an embodiment of the present disclosure.

[0054] Reference Figure 9 In step S901, in response to the interruption of communication between the pitch controller and the main controller of the wind turbine during normal operation of the pitch system, the pitch system is controlled to enter the redundant operation mode.

[0055] In step S902, under redundant operation mode, the rotor speed determination method described above is executed in a polling manner for each pitch motor of the wind turbine to determine the rotor speed of the wind turbine. In other words, the rotor speed determination method described above can be executed sequentially for the three pitch motors at predetermined time intervals. This reduces the influence of the torque data of each pitch motor on the determination of the rotor speed, allows for the identification of abnormal conditions of each pitch motor, and reduces the resource utilization of the pitch controller.

[0056] In step S903, in response to the fact that the rotor speed determined for each pitch motor is always less than or equal to a preset speed threshold within a preset time period, the pitch system is controlled to exit the redundant operation mode. In other words, the redundant operation mode will exit even if the wind turbine does not overspeed after a certain period of time. On the other hand, in response to the fact that the communication between the pitch controller and the main controller of the wind turbine returns to normal within the preset time period, the pitch system can be controlled to exit the redundant operation mode.

[0057] Optionally, in response to the pitch system exiting redundant operation mode, if communication between the wind turbine's pitch controller and the main controller is restored and the rotor speed obtained from the main controller is less than or equal to a preset speed threshold, the pitch system can be controlled to operate normally. However, if communication between the wind turbine's pitch controller and the main controller remains interrupted when the pitch system exits redundant operation mode, or if the rotor speed obtained from the main controller is greater than a preset speed threshold, a wind turbine fault shutdown can be triggered.

[0058] The pitch control method for wind turbines according to embodiments of the present disclosure can quickly and accurately determine the impeller speed by performing frequency domain transformation on the torque data of the pitch motor when communication between the main control system and the pitch system of the wind turbine is interrupted, thereby reducing the risk of overspeed of the wind turbine during redundant operation of the pitch system.

[0059] Figure 10 This is a block diagram illustrating a controller according to an embodiment of the present disclosure. The controller may be implemented as a pitch controller for a wind turbine.

[0060] Reference Figure 10The controller 1000 according to embodiments of the present disclosure includes a processor 1010 and a memory 1020. The processor 1010 may include (but is not limited to) a central processing unit (CPU), a digital signal processor (DSP), a microcomputer, a field-programmable gate array (FPGA), a system-on-a-chip (SoC), a microprocessor, an application-specific integrated circuit (ASIC), etc. The memory 1020 may store computer programs to be executed by the processor 10310. The memory 1020 may include high-speed random access memory and / or a non-volatile computer-readable storage medium. When the processor 1010 executes the computer program stored in the memory 1020, the rotor speed determination method and / or pitch control method of the wind turbine generator described above can be implemented.

[0061] Alternatively, the controller 1000 can communicate with various other components in the wind turbine unit via wired or wireless communication, and can also communicate with other devices in the wind farm (e.g., the wind farm's main controller) via wired or wireless communication. Furthermore, the controller 1000 can communicate with devices outside the wind farm via wired or wireless communication.

[0062] Figure 11 This is a control topology diagram of the pitch system of a wind turbine according to an embodiment of the present disclosure.

[0063] Reference Figure 11 The three blades of the wind turbine (blades 1101, 1102 and another one not in) Figure 11 The blades shown are mounted on hub 1103. Pitch controller 1105 and pitch drive 1106 are mounted in pitch control cabinet 1104. Pitch controller 1105 receives pitch commands from main controller 1108 installed in nacelle 1109 via communication line 1110 (e.g., but not limited to DP communication circuit) and sends pitch speed setpoints to pitch drive 1106. Pitch drive 1106 drives pitch motor 1107 according to the pitch speed setpoints, thereby realizing pitch operation. In addition to communication line 1110, power supply lines, safety chain lines, and other hardware control lines can also be provided between main controller 1108 and pitch controller 1105. Pitch controller 1105 can be connected via, for example, Figure 10 The controller 1000 shown is used to implement this.

[0064] The wind turbine rotor speed determination method and / or pitch control method according to embodiments of this disclosure can be programmed into a computer program and stored on a computer-readable storage medium. When the computer program is executed by a processor, the wind turbine rotor speed determination method and / or pitch control method as described above can be implemented. Examples of computer-readable storage media include: read-only memory (ROM), random access programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, non-volatile memory, CD-ROM, CD-R, CD+R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, Blu-ray or optical disc storage, hard disk drive (HDD), solid-state drive (SSD), card storage (such as multimedia cards, secure digital (SD) cards, or ultra-fast digital (XD) cards), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, and any other device configured to store a computer program and any associated data, data files, and data structures in a non-transitory manner and to provide the computer program and any associated data, data files, and data structures to a processor or computer so that the processor or computer can execute the computer program. In one example, the computer program and any associated data, data files, and data structures are distributed across a networked computer system, such that the computer program and any associated data, data files, and data structures are stored, accessed, and executed in a distributed manner through one or more processors or computers.

[0065] The method for determining the rotor speed, the pitch control method, and the controller for wind turbines according to embodiments of this disclosure can quickly and accurately determine the rotor speed by performing frequency domain transformation on the torque data of the pitch motor when communication between the main control system and the pitch system of the wind turbine is interrupted. This method is unaffected by the waveform characteristics, trends, features, or interference signals of the torque data, and is therefore unaffected by changes in wind direction or sudden changes in wind speed. As a result, it can be directly applied to various operating conditions of wind turbines.

[0066] Furthermore, the method for determining the rotor speed, the pitch control method, and the controller of the wind turbine according to the embodiments of this disclosure are applicable to both the wind turbine operation in high winds and the continuous pitch adjustment of the blades, as well as the situation where the pitch system maintains 0 speed. Therefore, compared with the existing methods, its scope of application is significantly expanded. That is, as long as the wind turbine is in the pitch state, the rotor speed can be effectively determined.

[0067] Furthermore, the method for determining the rotor speed, the pitch control method, and the controller for wind turbine generators according to the embodiments of this disclosure, compared with existing methods, improve the accuracy of determining the rotor speed by performing frequency domain transformation on the torque data of the pitch motor. This method is suitable for detecting torque changes under various operating conditions of wind turbine generators and provides necessary support for the stable operation of wind turbine generators.

[0068] Furthermore, the method for determining the rotor speed, the pitch control method, and the controller of the wind turbine according to the embodiments of this disclosure determine the rotor speed by performing frequency domain transformation on the torque data of the pitch motor. On the one hand, this avoids the problems of inaccurate measurement of low-speed speed values ​​and easy fluctuations caused by installing tilt sensors, proximity switches, and other devices. On the other hand, it does not require hardware modification of the pitch system, which can reduce hardware costs, technical modification costs, labor costs, and time costs of power generation loss caused by technical modifications.

[0069] While some embodiments of this disclosure have been shown and described, those skilled in the art will understand that modifications may be made to these embodiments without departing from the principles and spirit of this disclosure, which are defined by the claims and their equivalents.

Claims

1. A method for determining the impeller speed of a wind turbine generator, characterized in that, The method for determining the impeller speed includes: In response to a communication interruption between the pitch controller and the main controller of the wind turbine during normal operation of the pitch system, the torque data of the pitch motor is sampled. The frequency spectrum of the pitch motor torque data is obtained by performing frequency domain transformation on the sampled torque data. Based on the obtained spectrum, the rotor speed of the wind turbine is determined; The steps for determining the rotor speed of a wind turbine based on the obtained spectrum include: The rotor speed of the wind turbine is determined based on the frequency value corresponding to the maximum signal strength in the obtained spectrum. The step of determining the rotor speed of the wind turbine based on the obtained spectrum further includes: In response to the frequency value corresponding to the maximum signal strength in the obtained spectrum being less than a preset frequency threshold, the product of the frequency value and 60 is determined as the rotor speed of the wind turbine.

2. The method for determining impeller speed as described in claim 1, characterized in that, The method for determining the impeller speed also includes setting the number of sampling points and the sampling frequency before sampling the torque data of the pitch motor.

3. The method for determining impeller speed as described in claim 2, characterized in that, In response to the number of torque data samples reaching the set number of sampling points, or in response to the sampling duration of torque data reaching the preset duration, the sampled torque data is subjected to frequency domain transformation.

4. The method for determining impeller speed as described in claim 1, characterized in that, The frequency domain transformation includes the Fast Fourier Transform.

5. The method for determining impeller speed as described in claim 1, characterized in that, The steps of periodically sampling the torque data of the pitch motor, obtaining the spectrum of the torque data of the pitch motor, and determining the rotor speed of the wind turbine are performed.

6. A pitch control method for a wind turbine generator, characterized in that, The pitch control method includes: In response to a communication interruption between the pitch controller and the main controller of the wind turbine during normal operation of the pitch system, the pitch system is controlled to enter a redundant operation mode. In redundant operation mode, the impeller speed determination method described in any one of claims 1-5 is executed in a polling manner for each pitch motor of the wind turbine to determine the impeller speed of the wind turbine. In response to the fact that the impeller speed determined for each pitch motor is always less than or equal to a preset speed threshold within a preset time period, the pitch system is controlled to exit the redundant operation mode.

7. The pitch control method as described in claim 6, characterized in that, The pitch control method further includes: In response to the restoration of normal communication between the pitch controller and the main controller of the wind turbine within a preset time period, the pitch system is controlled to exit the redundant operation mode.

8. The pitch control method as described in claim 6 or 7, characterized in that, The pitch control method further includes: When the pitch system exits the redundant operation mode, the communication between the pitch controller and the main controller of the wind turbine returns to normal, and the rotor speed obtained from the main controller is less than or equal to the preset speed threshold, thus controlling the pitch system to operate normally. When the pitch system exits the redundant operation mode, the communication between the pitch controller and the main controller of the wind turbine is still interrupted, or the rotor speed obtained from the main controller is greater than the preset speed threshold, triggering a fault shutdown of the wind turbine.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the impeller speed determination method as described in any one of claims 1-5 or the pitch control method as described in any one of claims 6-8.

10. A controller, characterized in that, The controller includes: processor; and The memory stores a computer program that, when executed by a processor, implements the impeller speed determination method as described in any one of claims 1-5 or the pitch control method as described in any one of claims 6-8.

11. A wind turbine generator set, characterized in that, The wind turbine includes the controller as described in claim 10.

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