Control Method and Control Device for Wind Turbine

Abstract

Disclosed are a control method and a control device for a wind turbine generator set. The control method includes: periodically calculating a statistical value of the blade angle values measured by an encoder within a sampling time interval; in response to the calculated statistical values of a plurality of consecutive sampling time intervals being greater than a predetermined threshold, determining that the blade angle values measured by the encoder fluctuate; and in response to determining that the blade angle values measured by the encoder fluctuate, performing a specific pitch operation.

Description

Technical Field

[0001] The present disclosure generally relates to the technical field of wind power generation, and more specifically, to a control method and a control device for a wind turbine generator set. Background Art

[0002] With the gradual expansion of the scale of wind turbine generator sets and the increasingly perfect unit safety protection, the power generation performance of the operation of wind turbine generator sets, that is, improving the power generation amount and availability of wind turbines, has received more and more attention. On the other hand, while pursuing power generation benefits, the safety of wind turbine generator sets must be strictly ensured.

[0003] In a wind turbine generator set, a main function of the pitch system is to act as the aerodynamic braking system function of the unit. The electric pitch system ensures the safe and stable operation of the wind turbine generator set through various detection and control means and multiple redundancy designs. Any fault-caused shutdown will cause the blades to feather to the 90-degree position. Therefore, in order to protect the safety of the wind turbine generator set, the pitch system needs to monitor the sensor data and signals during operation in real time. If the sensor data and signals are abnormal, emergency feathering is required to retract the blades to a safe position. Here, an important sensor data is the blade angle value measured by the encoder of the pitch system.

[0004] At the same time, since the pitch driver needs to collect the signals of the encoder, when the encoder is damaged or the encoder signal is abnormal, the angle value collected by the pitch controller / main controller will jump, causing the wind turbine to trigger a fault and shut down. Even worse, it may cause the pitch motor to run abnormally and the current to increase, triggering a fault inside the pitch driver and shutting down, resulting in a stuck pitch phenomenon. At this time, the pitch motor can no longer drive the blades to feather to a safe position, thus posing a huge hidden danger to the safety of the wind turbine.

[0005] The encoder is a relatively precise and sensitive device. Abnormal working environments can cause damage to the encoder. Generally speaking, the main reasons for encoder failures are as follows.

[0006] First, the encoder itself fails or the grating is contaminated. This belongs to a failure of the components of the encoder itself.

[0007] Second, the encoder connection cable fails. This situation has the highest probability of occurrence. Usually, the encoder cable is open-circuited, short-circuited or has poor contact, or due to loose cable fixation, it causes welding open or open-circuit due to loosening.

[0008] Third, the encoder +5V power supply drops. This means that the +5V power supply is too low. Usually, the power supply cannot be lower than 4.75V. The reason for the low power supply is a power supply failure or excessive resistance of the power transmission cable, resulting in power loss.

[0009] Fourth, the shielding wire of the encoder cable is not connected or has fallen off. This situation will introduce interference signals, making the waveform unstable and affecting the accuracy of communication.

[0010] In these cases, when the encoder connection line becomes loose or the encoder has a device failure, it will cause a large-amplitude high-frequency fluctuation in the data output by the encoder. At this time, the main controller will detect that the three-axis angles of the wind turbine generator set are inconsistent, and thus activate the angle adjustment function. However, due to the frequent fluctuation of the angle data measured by the encoder, the given speed value will be disordered. In the case of frequent and drastic pitch adjustment and commutation, the toothed belt will be broken due to the frequent mutation of the force.

[0011] In addition, since the fluctuation frequency of the angle data measured by the encoder is relatively high and the time when the angle difference of the three blades continuously exceeds a certain threshold is less, the "angle inconsistency" fault will not be triggered inside the pitch system to perform self-pitching, which seriously affects the operation safety of the unit.

[0012] Currently, there are mainly four methods to detect whether the encoder has a fault, all of which are aimed at a single jump of the encoder. However, the methods for detecting a single jump cannot be used to detect the situation of large-amplitude and frequent fluctuations of the angle value, and the reasons are as follows.

[0013] One method for detecting a single jump is to judge the change rate of the angle value measured by the encoder before and after and limit the jump value. Since the jump moments and amplitudes of different encoders are different, it is difficult to reasonably set the parameter thresholds; in addition, when the actual speed of the pitch motor becomes larger, the encoder angle change value will also become larger. If this change rate is processed as a jump, the detection of the real fault of the pitch motor will be blocked, which is not conducive to the safety of the wind turbine generator set; in addition, this method cannot distinguish whether it is the abnormal operation of the pitch motor or the abnormality of the encoder data.

[0014] Another method for detecting a single jump is to install a blade encoder as a reference. The disadvantages of this method are as follows: on the one hand, it is impossible to judge which encoder value is the real value, and on the other hand, it is impossible to install an encoder on the blades of some pitch systems.

[0015] Another method for detecting a single jump is to increase the detection extension time. This method can filter out the data of a single jump, but when the encoder data fluctuates, it will cause the timer in the controller software to be frequently turned on and interrupted, resulting in the fact that the timing time of the timer can never reach the set value, so that the fault cannot be triggered, that is, the detection of the abnormal fluctuation of the encoder data cannot be realized; at the same time, since the fault cannot be triggered, it will also affect the safety of the wind turbine.

[0016] Another method for detecting a single jump needs to be redundantly designed based on the motor current value, or the given speed value, or the actual speed at the previous moment. The disadvantage of this method is that: in the case where the angle value fluctuates very frequently, the given speed will change, which will cause the pitch motor current value to change, and since the actual speed at the previous moment may also be in a jump state, the actual speed at the previous moment cannot be adopted, resulting in the failure of the method. Summary of the Invention

[0017] Embodiments of the present disclosure provide a control method and a control device for a wind turbine generator, which can accurately detect whether the blade angle value measured by an encoder fluctuates and make up for the deficiencies of the single jump detection method.

[0018] In one general aspect, a control method for a wind turbine generator is provided. The control method includes: periodically calculating a statistical value of the blade angle value measured by an encoder within a sampling time interval; in response to the calculated statistical values of a plurality of consecutive sampling time intervals being greater than a predetermined threshold, determining that the blade angle value measured by the encoder fluctuates; and in response to determining that the blade angle value measured by the encoder fluctuates, performing a specific pitch operation.

[0019] Optionally, the statistical value includes variance and standard deviation.

[0020] Optionally, the encoder is an encoder of the pitch system of the wind turbine generator, and the pitch system of the wind turbine generator includes a plurality of encoders. For each encoder, the steps of calculating the statistical value and subsequent steps are performed.

[0021] Optionally, performing the specific pitch operation includes one of the following items: performing a pitch-in operation for each blade to stop the wind turbine generator; disconnecting the external pitch safety chain and performing an open-loop feathering operation.

[0022] Optionally, the step of performing the specific pitch operation includes: performing the specific pitch operation based on the blade angle value measured by the encoder within a plurality of consecutive predetermined time intervals and the blade angle value measured by another encoder, where the another encoder is an encoder whose measured blade angle value does not fluctuate.

[0023] Optionally, the steps of performing a specific pitch operation include: calculating a first angle change amount and value for each of the consecutive plurality of predetermined time intervals; calculating a second angle change amount and value for each of the consecutive plurality of predetermined time intervals; comparing the first angle change amount and value with the second angle change amount and value for each predetermined time interval; and in response to the comparison result indicating that the first angle change amount and value are consistent with the second angle change amount and value for each predetermined time interval, stopping the operation of adjusting the blade angles to be consistent. Wherein, each predetermined time interval includes a plurality of sampling moments, and each sampling time interval includes a plurality of sampling moments. The first angle change amount and value for any one of the predetermined time intervals are calculated as follows: starting from the first sampling moment, calculating the angle change amount between the blade angle value measured by the encoder at each sampling moment and the blade angle value measured at the previous sampling moment, and summing up all the calculated angle change amounts as the first angle change amount and value for any one of the predetermined time intervals. The second angle change amount and value for any one of the predetermined time intervals are calculated as follows: starting from the first sampling moment, calculating the angle change amount between the blade angle value measured by the other encoder at each sampling moment and the blade angle value measured at the previous sampling moment, and summing up all the calculated angle change amounts as the second angle change amount and value for any one of the predetermined time intervals. The previous sampling moment of the first sampling moment is the last sampling moment of the previous predetermined time interval, and the previous sampling moment of the first sampling moment of the first predetermined time interval is the last sampling moment of the consecutive plurality of sampling time intervals.

[0024] Optionally, the steps of performing a specific pitch operation further include: in response to the comparison result indicating that the first angle change amount and value are consistent with the second angle change amount and value for each predetermined time interval, performing a pitch-in operation on each blade to stop the wind turbine generator.

[0025] Optionally, the steps of performing a pitch-in operation on each blade to stop the wind turbine generator include: calculating the current blade angle value based on the blade angle value at the previous sampling moment of the sampling moment when the blade angle value measured by the encoder jumps, the first angle change amount and value for each predetermined time interval, and the number of sampling moments for each predetermined time interval; and based on the current blade angle value, performing a pitch-in operation on the blade corresponding to the encoder.

[0026] Optionally, the step of calculating the current blade angle value includes: adding the first angle change amounts and values for each predetermined time interval to obtain a total angle change amount; multiplying the total angle change amount by the total number of sampling instants elapsed from the sampling instant at which the blade angle value measured by the encoder jumps to the current sampling instant, and dividing the result of the multiplication by the total number of sampling instants for the consecutive plurality of predetermined time intervals to obtain an additional angle change value; adding the blade angle value at the sampling instant immediately preceding the sampling instant at which the blade angle value measured by the encoder jumps to the additional angle change value as the current blade angle value.

[0027] Optionally, the step of performing a specific pitch operation further includes: in response to the comparison result indicating that the first angle change amounts and values and the second angle change amounts and values for each predetermined time interval are all consistent, disconnecting the external pitch safety chain and performing an open-loop feathering operation.

[0028] Optionally, the time length of the predetermined time interval is the same as the time length of the sampling time interval, or the time length of the predetermined time interval is different from the time length of the sampling time interval.

[0029] Optionally, each sampling time interval includes at least 5 sampling instants, and the number of the consecutive plurality of sampling time intervals is an integer greater than 3.

[0030] Optionally, each predetermined time interval includes at least 5 sampling instants, and the number of the consecutive plurality of predetermined time intervals is an integer greater than 5.

[0031] In another general aspect, there is provided a control device for a wind turbine generator, the control device including: a statistical value calculation unit configured to periodically calculate a statistical value of a blade angle value measured by an encoder within a sampling time interval; a fluctuation determination unit configured to determine that the blade angle value measured by the encoder fluctuates in response to the calculated statistical values for a consecutive plurality of sampling time intervals being greater than a predetermined threshold; and a pitch control unit configured to perform a specific pitch operation in response to determining that the blade angle value measured by the encoder fluctuates.

[0032] In another general aspect, there is provided a computer-readable storage medium storing a computer program, which when executed by a processor, implements the control method for a wind turbine generator as described above.

[0033] In another general aspect, there is provided a controller, the controller including: a processor; and a memory storing a computer program, which when executed by the processor, implements the control method for a wind turbine generator as described above.

[0034] The control method and control device of a wind turbine according to an embodiment of the present disclosure can accumulate and sum the angle change amount based on the characteristics of the angle value fluctuation and the characteristic that the angle value jumps and then recovers, so as to effectively remove the jump value of the angle and restore the true data value. In addition, the control method and control device of a wind turbine according to an embodiment of the present disclosure can prevent the toothed belt of the pitch motor from being broken due to the frequent fluctuation of the given value by detecting and processing the blade angle value measured by the encoder, protect the safety of mechanical components, and avoid further losses. Optionally, when it is detected that the blade angle value measured by the encoder fluctuates frequently, the control method and control device of a wind turbine according to an embodiment of the present disclosure can collect and calculate the difference between the blade angle values at two adjacent sampling moments, accumulate and sum them, and at the same time compare with the data of the normal axis. If the comparison result is consistent, it is determined that the encoder has indeed fluctuated, rather than a problem with the operation of the pitch system itself. Compared with the existing amplitude method, current method and other methods, this detection method is more effective for detecting frequent fluctuations and will not cause false detection and missed detection.

[0035] In addition, when it is detected that the blade angle value measured by the encoder fluctuates, the control method and control device of a wind turbine according to an embodiment of the present disclosure can stop the adjustment of the consistency of the three blade angles to prevent serious accidents caused by abnormal given speed. Compared with the existing angle jump detection method, the control method and control device of a wind turbine according to an embodiment of the present disclosure can accurately detect whether the blade angle value measured by the encoder fluctuates, making up for the deficiency of the single jump detection method. The reason is that: for single jump, redundant design needs to be carried out according to the motor current value, or the given speed value, or the actual speed at the previous moment. However, in the case of very frequent angle value fluctuations, the given speed will change, which will cause the motor current value to change, and since the actual speed at the previous moment may also be a jump, the blade angle value measured at the previous moment cannot actually be used.

[0036] In addition, compared with the existing amplitude method, current method and other methods, by accumulating and summing the angle change amount, the algorithm can be simplified and better results can be achieved. The reason is that: if the slope is compared, it is not easy to select the sampling period. If the period is not selected appropriately, the calculated slope will still change greatly. Therefore, the control method and control device of a wind turbine according to an embodiment of the present disclosure can accurately identify the fluctuation of the angle value measured by the encoder, protect the safety of the pitch system actuator, and can be applied to the situation of frequent angle value fluctuations caused by frequent interruptions of PROFIBUS-DP communication.

[0037] Additional aspects and / or advantages of the present disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other objects and features of the embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the drawings showing embodiments thereof, in which:

[0039] Figure 1 is a waveform diagram showing angle data after an encoder failure;

[0040] Figure 2 is a waveform diagram showing given speed data of a main controller after an encoder failure;

[0041] Figure 3 is a diagram showing an example of a pitch system of a wind turbine according to an embodiment of the present disclosure;

[0042] Figure 4 is a flowchart showing a control method of a wind turbine according to an embodiment of the present disclosure;

[0043] Figure 5 is a flowchart showing a fluctuation detection process according to an embodiment of the present disclosure;

[0044] Figure 6 is a flowchart showing a specific pitch operation according to an embodiment of the present disclosure;

[0045] Figure 7 is a flowchart showing a furling operation according to an embodiment of the present disclosure;

[0046] Figure 8 is a flowchart showing a specific pitch operation according to another embodiment of the present disclosure;

[0047] Figure 9 is a block diagram showing a control device of a wind turbine according to an embodiment of the present disclosure;

[0048] Figure 10 is a block diagram showing a controller of a wind turbine according to an embodiment of the present disclosure;

[0049] Figure 11 is a diagram showing an application effect of a control method of a wind turbine according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0050] The following specific embodiments are provided to assist the reader in obtaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. However, after understanding the disclosure of this application, various changes, modifications, and equivalents of the methods, apparatuses, and / or systems described herein will be apparent. For example, the order of operations described herein is merely exemplary and is not limited to those set forth herein, but may be changed as will be apparent after understanding the disclosure of this application, except for operations that must occur in a specific order. In addition, descriptions of features known in the art may be omitted for greater clarity and conciseness.

[0051] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Instead, the examples described herein are provided only to illustrate some of the many possible ways of implementing the methods, apparatuses, and / or systems described herein, which will be apparent after understanding the disclosure of this application.

[0052] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more of them.

[0053] Although terms such as "first", "second", and "third" may be used herein to describe various components, elements, regions, layers, or parts, these components, elements, regions, layers, or parts should not be limited by these terms. Instead, these terms are only used to distinguish one component, element, region, layer, or part from another. Thus, the first component, first element, first region, first layer, or first part referred to in the examples described herein may also be referred to as the second component, second element, second region, second layer, or second part without departing from the teachings of the examples.

[0054] In the specification, when an element (such as a layer, region, or substrate) is described as "on" another element, "connected to" or "coupled to" another element, the element may be directly "on" the other element, directly "connected to" or "coupled to" the other element, or there may be one or more other elements therebetween. In contrast, when an element is described as "directly on" another element, "directly connected to" or "directly coupled to" another element, there may be no other elements therebetween.

[0055] The terms used herein are for the purpose of describing various examples only and are not intended to limit the disclosure. Unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. The terms "comprising", "including", and "having" specify the presence of the recited features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0056] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains after understanding this disclosure. Unless explicitly defined herein, terms (such as those defined in a general dictionary) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and shall not be interpreted in an idealized or overly formal manner.

[0057] In addition, in the description of the examples, when it is considered that a detailed description of a related structure or function that is well-known will cause an ambiguous interpretation of this disclosure, such a detailed description will be omitted.

[0058] Figure 1 is a waveform diagram showing the angular data after a failure of the encoder.

[0059] In Figure 1 , the abscissa is the time value, and the ordinate is the angular value (unit: degree). Starting from the -7 second moment, the angular value has large-amplitude and high-frequency fluctuations. And because the fluctuation frequency is too high, the time when the difference of the three-axis angles is too large each time is always less than the triggering time of the fault setting time, and the pitch system does not trigger the "large position deviation fault", resulting in the pitch system not performing autonomous feathering. In the case of the main controller controlling the shutdown, since the main controller detects that the angles of the three blades are inconsistent, the main controller will start the angle consistency adjustment function. Here, the 0 second moment can represent the moment when the fault is triggered due to the fluctuation of the angular value (i.e., the moment when the main controller starts the angle consistency adjustment function).

[0060] Figure 2 is a waveform diagram showing the given speed data of the main controller after a failure of the encoder.

[0061] In Figure 2 , the abscissa is the time value, and the ordinate is the speed value (unit: degree / second). Starting from the -7 second moment, the given speed value has frequent fluctuations. In this case, it will cause the pitch motor to commutate frequently, and the force on the toothed belt changes frequently, which may ultimately cause the toothed belt to be broken.

[0062] The control method and control device of the wind turbine according to the embodiments of the present disclosure can effectively detect the frequent fluctuations of the blade angle value measured by the encoder, avoid the frequent change of the force on the toothed belt caused by the frequent commutation of the pitch motor, and even cause the toothed belt to be broken. The following will refer to Figures 3 to 11 to describe in detail the control method and control device of the wind turbine according to the embodiments of the present disclosure.

[0063] Figure 3 is a diagram showing an example of the pitch system of the wind turbine according to the embodiments of the present disclosure.

[0064] Referring to Figure 3 , the pitch system may include a pitch motor 301, a super capacitor 302, a pitch controller 303, a pitch driver 304, an enable switch (limit switch) 305, a brake relay 306, and an encoder 307.

[0065] When the pitch driver 304 is operating normally, the enable switch (limit switch) 305 is in a closed state, and the pitch driver 304 is powered on. When the pitch controller 303 receives a pitch speed instruction from the main controller of the wind turbine generator set, or when the pitch controller 303 detects a fault in the pitch system and performs a self-pitching operation, the pitch controller 303 sends a speed command and an enable signal to the pitch driver 304. After receiving the speed command and the enable signal, the pitch driver 304 controls the brake relay 306 to release the brake, and provides an output voltage through the power output to drive the pitch motor 301 to rotate, thereby realizing the pitch adjustment function.

[0066] The encoder 307 can measure the blade angle value of the wind turbine generator set and provide the measured blade angle value to the pitch driver 304 and / or the pitch controller 303. The pitch driver 304 and / or the pitch controller 303 can calculate the rotation speed of the pitch motor 301 based on the read encoder value. The pitch driver 304 compares the calculated rotation speed with the value of the speed command sent by the pitch controller 303 to the pitch driver 304. If the calculated rotation speed is less than the value of the speed command, the pitch driver 304 can increase the voltage of the power output to increase the rotation speed of the pitch motor 301. If the calculated rotation speed is greater than the value of the speed command, the pitch driver 304 will decrease the voltage of the power output to reduce the rotation speed of the pitch motor 301. In this way, finally, the rotation speed of the pitch motor 301 can be made consistent with the value of the given speed command.

[0067] The pitch controller 303 can control the overall operation of the pitch system and can communicate with the main controller of the wind turbine generator set to receive control instructions sent by the main controller and / or send the status information of the pitch system to the main controller. The control method of the wind turbine generator set according to the embodiments of the present disclosure can be executed by the main controller of the wind turbine generator set. However, the present disclosure is not limited thereto. For example, the control method of the wind turbine generator set according to the embodiments of the present disclosure can be executed by each pitch controller.

[0068] Figure 4 is a flowchart showing the control method of the wind turbine generator set according to the embodiments of the present disclosure.

[0069] Referring to Figure 4, in step S401, the statistical values of the blade angle values measured by the encoder within the sampling time interval can be calculated periodically. The statistical values can include variance and standard deviation. In step S402, in response to the calculated statistical values of consecutive multiple sampling time intervals being greater than a predetermined threshold, it can be determined that the blade angle values measured by the encoder fluctuate. Each sampling time interval can include multiple sampling moments (e.g., but not limited to at least 5 sampling moments), and the number of consecutive multiple sampling time intervals can be, for example, 3 or more. In step S403, in response to determining that the blade angle values measured by the encoder fluctuate, a specific pitch operation can be performed. Here, the encoder is an encoder of the pitch system of the wind turbine generator set, and the pitch system of the wind turbine generator set includes multiple (e.g., 3) encoders. Steps S401 to S403 can be performed for each of the multiple encoders. Therefore, as described above, the control method of the wind turbine generator set according to the embodiments of the present disclosure can be executed by the main controller of the wind turbine generator set.

[0070] However, the control method of the wind turbine generator set according to the embodiments of the present disclosure can be executed by each pitch controller. When each pitch controller executes the control method of the wind turbine generator set according to the embodiments of the present disclosure, each pitch controller can provide the blade angle values measured by the corresponding encoder to the main controller of the wind turbine generator set, and can receive the blade angle values measured by other encoders from the main controller of the wind turbine generator set. In addition, each pitch controller can perform a specific pitch operation based on the blade angle values measured by the corresponding encoder and the blade angle values measured by other encoders (i.e., another encoder whose measured blade angle values do not fluctuate) received from the main controller of the wind turbine generator set in the case where the blade angle values measured by the corresponding encoder fluctuate.

[0071] According to the embodiments of the present disclosure, steps S401 and S402 can be referred to as a fluctuation detection process. Later, reference will be made to Figure 5 the fluctuation detection process in more detail.

[0072] In step S403, in response to determining that the blade angle values measured by the encoder fluctuate, a feathering operation can be performed for each blade to stop the wind turbine generator set, or, disconnect the external pitch safety chain and perform an open-loop feathering operation. On the other hand, in step S403, a specific pitch operation can be performed based on the blade angle values measured by the encoder whose measured blade angle values fluctuate within consecutive multiple predetermined time intervals and the blade angle values measured by another encoder (i.e., the encoder whose measured blade angle values do not fluctuate). Later, reference will be made to Figure 6 the process of performing the specific pitch operation in more detail.

[0073] Figure 5It is a flowchart showing a fluctuation detection process according to an embodiment of the present disclosure.

[0074] Referring to Figure 5 , in step S501, the count value n of the counter can be set to 1. In step S502, the blade angle value measured by the encoder within the sampling time interval Ts can be collected. In step S503, the statistical value of the blade angle value measured by the encoder within the sampling time interval Ts can be calculated. According to an embodiment of the present disclosure, the sampling time interval Ts may include a plurality of sampling moments. For example, the sampling time interval Ts may include at least 5 sampling moments. In addition, the statistical value may include variance and standard deviation. In step S504, it can be determined whether the calculated statistical value is greater than a predetermined threshold. According to an embodiment of the present disclosure, the predetermined threshold can be arbitrarily set by those skilled in the art according to actual needs. Generally, when the blade angle value measured by the encoder does not fluctuate, the variance of the blade angle value measured by the encoder within the sampling time interval is usually very small, and the maximum will not exceed 2. Therefore, when the statistical value is variance, the predetermined threshold can be set to, for example, 5. On the other hand, when the statistical value is standard deviation, the predetermined threshold can also be appropriately set. According to an embodiment of the present disclosure, by using the statistical value (e.g., variance or standard value) of the blade angle value measured by the encoder, it can be more accurately determined whether the blade angle value measured by the encoder fluctuates.

[0075] If the calculated statistical value is greater than the predetermined threshold, it indicates that the blade angle value measured by the encoder fluctuates within the current sampling time interval. At this time, in step S505, the count value of the counter can be incremented by 1, that is, the count value n = n + 1. Then, in step S506, it can be determined whether the count value reaches the threshold number. According to an embodiment of the present disclosure, the threshold number can be, for example, an integer greater than 3, but is not limited thereto. If the count value reaches the threshold number, it means that the calculated statistical values of consecutive threshold number of sampling time intervals are all greater than the predetermined threshold. Therefore, in step S507, it can be finally determined that the blade angle value measured by the encoder fluctuates. However, if the count value does not reach the threshold number, step S502 can be returned to collect the blade angle value measured by the encoder within the next sampling time interval Ts.

[0076] However, if the calculated statistical value is not greater than a predetermined threshold, it indicates that the blade angle value measured by the encoder within the current sampling time interval has not fluctuated. At this time, step S501 can be returned to reset the count value n of the counter to 1 and restart the fluctuation detection process. In other words, as long as the statistical value of the blade angle value measured by the encoder within a certain sampling time interval is not greater than the predetermined threshold before the count value reaches the threshold quantity, it will not be determined that the blade angle value measured by the encoder has fluctuated, and the fluctuation detection process will restart. According to an embodiment of the present disclosure, by determining that the calculated statistical values of consecutive multiple sampling time intervals are greater than the predetermined threshold, and finally determining that the blade angle value measured by the encoder has fluctuated, the accuracy and reliability of determining that the blade angle value measured by the encoder has fluctuated can be further improved.

[0077] Figure 6 is a flowchart showing a specific pitch operation according to an embodiment of the present disclosure. As described above, the main controller of the wind turbine generator set can perform a specific pitch operation on the blade corresponding to the encoder whose measured blade angle value fluctuates, or the pitch controller corresponding to the encoder whose measured blade angle value fluctuates can perform a specific pitch operation on the blade corresponding to it.

[0078] Refer to Figure 6 , in step S601, the sum of the first angle change amounts for each of consecutive multiple predetermined time intervals can be calculated. Here, similar to the sampling time interval, each predetermined time interval can also include multiple sampling moments (such as but not limited to at least 5 sampling moments). In addition, the time length of the predetermined time interval can be the same as or different from the time length of the sampling time interval. The number of consecutive multiple predetermined time intervals can be, for example, 5 or more.

[0079] According to an embodiment of the present disclosure, for each predetermined time interval, starting from the first sampling moment, the angle change amount between the blade angle value measured by the first encoder at each sampling moment and the blade angle value measured at the previous sampling moment can be calculated, and the sum of all the calculated angle change amounts is used as the sum of the first angle change amounts for this predetermined time interval. According to an embodiment of the present disclosure, the first encoder can be the encoder whose measured blade angle value is determined to have fluctuated during the fluctuation detection process. Optionally, the previous sampling moment of the first sampling moment for each predetermined time interval can be the last sampling moment of the previous predetermined time interval. For the first predetermined time interval, the previous sampling moment of its first sampling moment can be the last sampling moment during the fluctuation detection process.

[0080] In step S602, the second angular change amount and value for each of a plurality of consecutive predetermined time intervals can be calculated. As described above, each predetermined time interval may include a plurality of sampling moments, and the time length of the predetermined time interval may be the same as or different from the time length of the sampling time interval. According to an embodiment of the present disclosure, for each predetermined time interval, starting from the first sampling moment, the angular change amount between the blade angle value measured by the second encoder at each sampling moment and the blade angle value measured at the previous sampling moment can be calculated, and the sum of all the calculated angular change amounts is used as the second angular change amount and value for the predetermined time interval. According to an embodiment of the present disclosure, the second encoder may be an encoder for which it is determined that the measured blade angle value does not fluctuate during the fluctuation detection process.

[0081] Next, in step S603, the first angular change amount and value for each predetermined time interval can be compared with the second angular change amount and value. In step S604, in response to the comparison result indicating that the first angular change amount and value and the second angular change amount and value for each predetermined time interval are both consistent, the consistency adjustment operation of the blade angle can be stopped. Here, if the difference between the first angular change amount and value and the second angular change amount and value is less than, for example, 0.05 degrees, it can be determined that the first angular change amount and value and the second angular change amount and value are consistent. If the first angular change amount and value and the second angular change amount and value for a plurality of consecutive predetermined time intervals are both consistent, it can be determined that the blade angle value measured by the encoder has indeed fluctuated, rather than the pitch drive or pitch motor operating abnormally.

[0082] More specifically, in step S604, in response to the comparison result indicating that the first angular change amount and value and the second angular change amount and value for each predetermined time interval are both consistent, a blade retraction operation can be performed for each blade to stop the wind turbine generator. The implementation of the blade retraction operation will be described in more detail below with reference to Figure 7 More specifically, the implementation of the blade retraction operation will be described.

[0083] Figure 7 is a flowchart showing the blade retraction operation according to an embodiment of the present disclosure.

[0084] Refer to Figure 7, in step S701, the current blade angle value can be calculated based on the blade angle value at the previous sampling moment of the sampling moment when the blade angle value measured by the first encoder jumps, the sum of the first angle change amounts and values for each predetermined time interval, and the number of sampling moments for each predetermined time interval. As described above, the first encoder is the encoder for which the measured blade angle value fluctuates during the fluctuation detection process. Specifically, in step S701, first, the sum of the first angle change amounts and values for each predetermined time interval can be added to obtain the total angle change amount. Then, the total angle change amount can be multiplied by the total number of sampling moments experienced from the sampling moment when the blade angle value measured by the first encoder jumps to the current sampling moment, and the result of the multiplication can be divided by the total number of sampling moments for a plurality of predetermined time intervals (i.e., the total number of sampling moments for all predetermined time intervals from the predetermined time interval to which the sampling moment when the blade angle value measured by the first encoder jumps belongs to the current predetermined time interval) to obtain the additional angle change value. Finally, the blade angle value at the previous sampling moment of the sampling moment when the blade angle value measured by the first encoder jumps can be added to the obtained additional angle change value as the current blade angle value.

[0085] In step S702, based on the current blade angle value, a blade folding operation can be performed for the blade corresponding to the encoder. At this time, for the blades corresponding to other encoders, the blade folding operation can be normally performed. The process of calculating the current blade angle value will be described below with reference to the data given in Table 1.

[0086] Table 1 shows data such as the blade angle values and the sum of angle change amounts for a normal axis (a pitch axis where the blade angle value measured by the encoder does not fluctuate) and an abnormal axis (a pitch axis where the blade angle value measured by the encoder fluctuates).

[0087] Table 1

[0088]

[0089]

[0090]

[0091] Referring to Table 1, the time length of each predetermined time interval can be, for example, 200 ms, and each predetermined time interval can include, for example, 10 sampling moments. It can be seen from Table 1 that although the blade angle value measured by the encoder on the abnormal axis fluctuates, the sum of the angle change amounts for each predetermined time interval of the normal axis and the abnormal axis is the same. Thus, it can be seen that the blade angle value measured by the encoder on the abnormal axis indeed fluctuates.

[0092] Here, it is assumed that the blade retraction operation starts at the first sampling moment of the sixth predetermined time interval, and the blade angle value at the first sampling moment of the first predetermined time interval has fluctuated. Therefore, by adding the first angle change amounts and values of the six predetermined time intervals, the total angle change amount can be obtained as 5.07. The total number of sampling moments experienced from the first sampling moment of the first predetermined time interval to the first sampling moment of the sixth predetermined time interval is 50, and the result of multiplying it by 5.07 is 253.5. The result of the multiplication is divided by the total number of sampling moments of the six predetermined time intervals, which is 60, to obtain an additional angle change value of 4.23. Finally, by adding the blade angle value of 8.91 at the previous sampling moment before the first sampling moment of the first predetermined time interval to the obtained additional angle change value of 4.23, the current blade angle value can be obtained as 13.14. At this time, the blade angle value measured by the encoder on the normal axis is 13.16, and the two are basically the same. Therefore, the synchronous blade retraction of the three blades can be achieved.

[0093] The description given above is only an example, and the present disclosure is not limited thereto. For example, the blade retraction operation can start at any sampling moment after the fifth predetermined time interval, and its blade angle value can be calculated similarly.

[0094] Next, referring back to Figure 6 Optionally, in step S604, in response to the comparison result indicating that the first angle change amount and value of each predetermined time interval are consistent with the second angle change amount and value, for the blade corresponding to the first encoder, the external pitch safety chain can be disconnected and the open-loop pitch reduction operation can be performed.

[0095] According to an embodiment of the present disclosure, the advantage of performing the blade retraction operation or disconnecting the external pitch safety chain by restoring the blade angle value is that when the angle value measured by the encoder fluctuates too frequently, since the change time of the angle value is less than the delay time of the fault, the existing faults in the pitch controller / master controller cannot be triggered; while in the case of performing the blade retraction operation or disconnecting the external pitch safety chain and performing the open-loop pitch reduction operation by restoring the blade angle value, the pitch system can perform a constant pitch reduction speed without relying on the angle value measured by the encoder, so that the given speed value will not fluctuate frequently, thereby protecting the toothed belt from being pulled off.

[0096] Figure 8 is a flowchart showing a specific pitch operation according to another embodiment of the present disclosure.

[0097] Referring to Figure 8, in step S801, the count value m of the counter can be set to 1. In step S802, the sum value of the first angle change and the sum value of the second angle change for the m-th predetermined time interval can be calculated. As described above, for the m-th predetermined time interval, starting from the first sampling moment, the angle change amount between the blade angle value measured by the first encoder at each sampling moment and the blade angle value measured at the previous sampling moment can be calculated, and the sum of all calculated angle change amounts is used as the sum value of the first angle change for this predetermined time interval. At the same time, for the m-th predetermined time interval, starting from the first sampling moment, the angle change amount between the blade angle value measured by the second encoder at each sampling moment and the blade angle value measured at the previous sampling moment can be calculated, and the sum of all calculated angle change amounts is used as the sum value of the second angle change for this predetermined time interval. The first encoder can be the encoder for which the measured blade angle value fluctuates during the fluctuation detection process, and the second encoder can be the encoder for which the measured blade angle value does not fluctuate during the fluctuation detection process. The previous sampling moment of the first sampling moment of the m-th predetermined time interval can be the last sampling moment of the previous predetermined time interval. When m = 1, the previous sampling moment of the first sampling moment of the m-th predetermined time interval can be the last sampling moment during the fluctuation detection process.

[0098] Next, in step S803, the sum value of the first angle change and the sum value of the second angle change for the m-th predetermined time interval can be compared. If in step S803, the sum value of the first angle change and the sum value of the second angle change for the m-th predetermined time interval are consistent, then in step S804, the count value of the counter can be incremented by 1, that is, the count value m = m + 1. Then, in step S805, it can be determined whether the count value reaches the threshold number. According to an embodiment of the present disclosure, the threshold number can be, for example, an integer greater than or equal to 5, but is not limited thereto. If in step S805, the count value reaches the threshold number, it indicates that the sum value of the first angle change and the sum value of the second angle change for m consecutive predetermined time intervals are both consistent. Therefore, in step S806, the consistency adjustment operation of the blade angle can be stopped. Further, in step S806, for the blade corresponding to the first encoder, a blade folding operation can be performed, or the external pitch safety chain can be disconnected and an open-loop feathering operation can be performed. On the other hand, if in step S805, the count value does not reach the threshold number, it can return to step S802 to calculate the sum value of the first angle change and the sum value of the second angle change for the m-th predetermined time interval again.

[0099] Optionally, if in step S803, the sum of the first angular change amounts and values and the sum of the second angular change amounts and values in the m-th predetermined time interval are inconsistent, the method may be exited without performing a specific pitch operation on the blade corresponding to the first encoder. In other words, in this case, it is not determined that the blade angle value measured by the encoder fluctuates, but other processing is performed (for example, performing a blade angle consistency adjustment operation or other fault operations).

[0100] Figure 9 is a block diagram showing a control device of a wind turbine according to an embodiment of the present disclosure.

[0101] The control device 900 of the wind turbine according to an embodiment of the present disclosure may be implemented in the main controller of the wind turbine. Optionally, the control device 900 of the wind turbine may be implemented in each pitch controller of the wind turbine. As described above, when the control device 900 of the wind turbine is implemented in each pitch controller of the wind turbine, each pitch controller may provide the blade angle value measured by the corresponding encoder to the main controller of the wind turbine, and may receive the blade angle values measured by other encoders from the main controller of the wind turbine.

[0102] Referring to Figure 9 , the control device 900 of the wind turbine may include a statistical value calculation unit 910, a fluctuation determination unit 920, and a pitch control unit 930. The statistical value calculation unit 910 may periodically calculate the statistical values of the blade angle values measured by the encoder within the sampling time interval. The statistical values may include variance and standard deviation. The fluctuation determination unit 920 may determine that the blade angle value measured by the encoder fluctuates in response to the calculated statistical values in a plurality of consecutive sampling time intervals being greater than a predetermined threshold. The pitch control unit may perform a specific pitch operation in response to determining that the blade angle value measured by the encoder fluctuates. Here, the encoder is an encoder of the pitch system of the wind turbine, and the pitch system of the wind turbine includes a plurality of (for example, 3) encoders. Each sampling time interval may include a plurality of sampling moments (for example, but not limited to at least 5 sampling moments), and the number of consecutive sampling time intervals may be, for example, 3 or more.

[0103] The pitch control unit 930 may perform a specific pitch operation in response to determining that the blade angle value measured by the encoder fluctuates. For example, in response to determining that the blade angle value measured by the encoder fluctuates, the pitch control unit 930 may perform a feathering operation for each blade to stop the wind turbine generator, or disconnect the external pitch safety chain and perform an open-loop feathering operation. Further, the pitch control unit 930 may perform a specific pitch operation based on the blade angle values measured by the encoder that fluctuate within a plurality of consecutive predetermined time intervals and the blade angle values measured by another encoder (i.e., the encoder whose measured blade angle value does not fluctuate).

[0104] According to an embodiment of the present disclosure, in response to determining that the blade angle value measured by the encoder fluctuates, the pitch control unit 930 may calculate a first angle change amount and value for each of a plurality of consecutive predetermined time intervals, calculate a second angle change amount and value for each of the plurality of consecutive predetermined time intervals, compare the first angle change amount and value of each predetermined time interval with the second angle change amount and value, and stop the blade angle consistency adjustment operation in response to the comparison result indicating that the first angle change amount and value of each predetermined time interval are consistent with the second angle change amount and value. Here, similar to the sampling time interval, each predetermined time interval may also include a plurality of sampling moments (e.g., but not limited to at least 5 sampling moments). In addition, the time length of the predetermined time interval may be the same as or different from the time length of the sampling time interval. The number of the plurality of consecutive predetermined time intervals may be, for example, 5 or more. For each predetermined time interval, starting from the first sampling moment, the angle change amount between the blade angle value measured by the first encoder at each sampling moment and the blade angle value measured at the previous sampling moment may be calculated, and the sum of all the calculated angle change amounts is used as the first angle change amount and value of the predetermined time interval. According to an embodiment of the present disclosure, the first encoder may be the encoder whose determined measured blade angle value fluctuates. Optionally, the previous sampling moment of the first sampling moment of each predetermined time interval may be the last sampling moment of the previous predetermined time interval. For the first predetermined time interval, the previous sampling moment of its first sampling moment may be the last sampling moment during the fluctuation detection process. In addition, for each predetermined time interval, starting from the first sampling moment, the angle change amount between the blade angle value measured by the second encoder at each sampling moment and the blade angle value measured at the previous sampling moment may be calculated, and the sum of all the calculated angle change amounts is used as the second angle change amount and value of the predetermined time interval. According to an embodiment of the present disclosure, the second encoder may be the encoder whose determined measured blade angle value does not fluctuate during the fluctuation detection process.

[0105] In response to the comparison result indicating that the sum of the first angular change amounts and values and the sum of the second angular change amounts and values for each predetermined time interval are both consistent, the pitch control unit 930 may perform a pitch-in operation on the blade corresponding to the first encoder. For example, the pitch control unit 930 may calculate the current blade angle value based on the blade angle value at the previous sampling moment of the sampling moment when the blade angle value measured by the first encoder jumps, the sum of the first angular change amounts and values for each predetermined time interval, and the number of sampling moments at each predetermined time interval. Specifically, the pitch control unit 930 may add up the sum of the first angular change amounts and values for each predetermined time interval to obtain the total angular change amount. Then, the pitch control unit 930 may multiply the total angular change amount by the total number of sampling moments experienced from the sampling moment when the blade angle value measured by the first encoder jumps to the current sampling moment, and divide the result of the multiplication by the total number of sampling moments of a continuous plurality of predetermined time intervals to obtain an additional angular change value. Finally, the pitch control unit 930 may add the blade angle value at the previous sampling moment of the sampling moment when the blade angle value measured by the first encoder jumps to the additional angular change value as the current blade angle value. After calculating the current blade angle value, the pitch control unit 930 may perform a pitch-in operation on the blade corresponding to the first encoder based on the calculated current blade angle value.

[0106] Optionally, in response to the comparison result indicating that the sum of the first angular change amounts and values and the sum of the second angular change amounts and values for each predetermined time interval are both consistent, the pitch control unit 930 may disconnect the external pitch safety chain and perform an open-loop feathering operation.

[0107] Figure 10 is a block diagram showing a controller of a wind turbine according to an embodiment of the present disclosure.

[0108] Refer to Figure 10, the controller 1000 of the wind turbine according to an embodiment of the present disclosure may be, but is not limited to, a pitch controller, a main controller of the wind turbine, etc. As described above, the three blades of the wind turbine respectively correspond to one axis, and each axis has a pitch controller, a pitch driver, and a pitch motor. The controller 1000 of the wind turbine according to an embodiment of the present disclosure may include 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 chip (SoC), a microprocessor, an application specific integrated circuit (ASIC), etc. The memory 1020 stores a computer program to be executed by the processor 1010. The memory 1020 includes a 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 control method of the wind turbine as described above can be implemented.

[0109] Optionally, the controller 1000 can communicate with other components in the wind turbine in a wired / wireless communication manner, and can also communicate with other devices in the wind farm in a wired / wireless communication manner. In addition, the controller 1000 can communicate with devices outside the wind farm in a wired / wireless communication manner.

[0110] Figure 11 is a diagram showing the application effect of the control method of the wind turbine according to an embodiment of the present disclosure.

[0111] Referring to Figure 11 , through the fluctuation detection process and the specific pitch operation, the frequently fluctuating blade angle values (as shown by the thin solid line in Figure 11 ) can be restored to normal blade angle values (as shown by the thick solid line in Figure 11 ).

[0112] The control method of a wind turbine according to an embodiment of the present disclosure can be written as a computer program and stored on a computer-readable storage medium. When the computer program is executed by a processor, the control method of the wind turbine 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-RLTH, BD-RE, Blu-ray or optical disc memory, hard disk drive (HDD), solid state drive (SSD), card memory (such as, multimedia card, secure digital (SD) card or extreme digital (XD) card), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid state disk and any other device, any other device configured to store a computer program and any associated data, data files and data structures in a non-transitory manner and provide the computer program and any associated data, data files and data structures to a processor or computer such 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 by one or more processors or computers.

[0113] The control method and control device of a wind turbine according to an embodiment of the present disclosure can accumulate and sum the angle change amount based on the characteristics of the angle value fluctuation and the characteristic that the angle value jumps and then recovers, so as to effectively remove the jump value of the angle and restore the true data value. In addition, the control method and control device of a wind turbine according to an embodiment of the present disclosure can prevent the toothed belt of the pitch motor from being broken due to the frequent fluctuation of the given value by detecting and processing the blade angle value measured by the encoder, protect the safety of mechanical components, and avoid further losses. Optionally, when it is detected that the blade angle value measured by the encoder fluctuates frequently, the control method and control device of a wind turbine according to an embodiment of the present disclosure can collect and calculate the difference between the blade angle values at two adjacent sampling moments, accumulate and sum them, and at the same time compare with the data of the normal axis. If the comparison result is consistent, it is determined that the encoder has indeed fluctuated, rather than a problem with the operation of the pitch system itself. Compared with the existing amplitude method, current method and other methods, this detection method is more effective for detecting frequent fluctuations and will not cause false detection and missed detection.

[0114] In addition, when it is detected that the blade angle value measured by the encoder fluctuates, the control method and control device of a wind turbine according to an embodiment of the present disclosure can stop the adjustment of the consistency of the three blade angles to prevent serious accidents caused by abnormal given speed. Compared with the existing angle jump detection method, the control method and control device of a wind turbine according to an embodiment of the present disclosure can accurately detect whether the blade angle value measured by the encoder fluctuates, making up for the deficiency of the single jump detection method. The reason is that: for single jump, redundant design needs to be carried out according to the motor current value, or the given speed value, or the actual speed at the previous moment. However, in the case of very frequent angle value fluctuations, the given speed will change, which will cause the motor current value to change, and since the actual speed at the previous moment may also be a jump, the blade angle value measured at the previous moment cannot actually be used.

[0115] In addition, compared with the existing amplitude method, current method and other methods, by accumulating and summing the angle change amount, the algorithm can be simplified and better effects can be achieved. This is because: if the slopes are compared, it is not easy to select the sampling period. If the period is not selected appropriately, the calculated slope will still change greatly. Therefore, the control method and control device of a wind turbine according to an embodiment of the present disclosure can accurately identify the fluctuation of the angle value measured by the encoder, protect the safety of the pitch system actuator, and can be applied to the situation where the angle value fluctuates frequently due to frequent interruption of PROFIBUS-DP communication.

[0116] Although some embodiments of the present disclosure have been shown and described, those skilled in the art should understand that these embodiments can be modified without departing from the principles and spirit of the present disclosure, which is defined by the claims and their equivalents.

Claims

1. A control method for a wind power generation set, characterized in that, The control method includes: Periodically calculating a statistical value of the blade angle values measured by the encoder within a sampling time interval; In response to the calculated statistical values of consecutive multiple sampling time intervals being greater than a predetermined threshold, determining that the blade angle values measured by the encoder fluctuate; In response to determining that the blade angle values measured by the encoder fluctuate, performing a specific pitch operation, wherein the step of performing the specific pitch operation includes: Calculating a sum value of the first angle change amounts for each of consecutive multiple predetermined time intervals; Calculating a sum value of the second angle change amounts for each of the consecutive multiple predetermined time intervals; Comparing the sum value of the first angle change amounts with the sum value of the second angle change amounts for each predetermined time interval; In response to the comparison result indicating that the sum value of the first angle change amounts and the sum value of the second angle change amounts for each predetermined time interval are both consistent, stopping the operation of adjusting the blade angle consistency, wherein each predetermined time interval includes multiple sampling instants, and each sampling time interval includes multiple sampling instants.

2. The control method according to claim 1, wherein Performing the specific pitch operation includes one of the following items: Performing a blade retraction operation for each blade to stop the wind turbine generator; Disconnecting the external pitch safety chain and performing an open-loop feathering operation.

3. The control method according to claim 1, wherein The sum value of the first angle change amounts for any one predetermined time interval is calculated as follows: starting from the first sampling instant, calculating the angle change amount between the blade angle value measured by the encoder at each sampling instant and the blade angle value measured at the previous sampling instant, and summing all the calculated angle change amounts as the sum value of the first angle change amounts for any one predetermined time interval, wherein the sum value of the second angle change amounts for any one predetermined time interval is calculated as follows: starting from the first sampling instant, calculating the angle change amount between the blade angle value measured by the other encoder at each sampling instant and the blade angle value measured at the previous sampling instant, and summing all the calculated angle change amounts as the sum value of the second angle change amounts for any one predetermined time interval, wherein the other encoder is the encoder for which the measured blade angle value does not fluctuate, wherein the previous sampling instant of the first sampling instant is the last sampling instant of the previous predetermined time interval, and the previous sampling instant of the first sampling instant of the first predetermined time interval is the last sampling instant of the consecutive multiple sampling time intervals.

4. The control method according to claim 3, characterized in that The step of performing the specific pitch operation further includes: In response to the comparison result indicating that the sum value of the first angle change amounts and the sum value of the second angle change amounts for each predetermined time interval are both consistent, performing a blade retraction operation for each blade to stop the wind turbine generator.

5. The control method according to claim 4, characterized in that The step of performing a blade retraction operation for each blade to stop the wind turbine generator includes: Based on the blade angle value at the previous sampling instant of the sampling instant at which the blade angle value measured by the encoder jumps, the sum value of the first angle change amounts for each predetermined time interval, and the number of sampling instants for each predetermined time interval, calculating the current blade angle value; Based on the current blade angle value, perform a blade folding operation on the blade corresponding to the encoder.

6. The control method according to claim 5, wherein The steps of calculating the current blade angle value include: Add the first angle change amounts and values for each predetermined time interval to obtain the total angle change amount; Multiply the total angle change amount by the total number of sampling times experienced from the sampling time when the blade angle value measured by the encoder jumps to the current sampling time, and divide the multiplied result by the total number of sampling times of the continuous multiple predetermined time intervals to obtain an additional angle change value; Add the blade angle value at the previous sampling time of the sampling time when the blade angle value measured by the encoder jumps to the additional angle change value as the current blade angle value.

7. The control method according to claim 3, wherein The steps of performing a specific pitch operation further include: In response to the comparison result indicating that the first angle change amounts and values and the second angle change amounts and values for each predetermined time interval are all consistent, disconnect the external pitch safety chain and perform an open-loop blade folding operation.

8. The control method according to claim 3, wherein, The time length of the predetermined time interval is the same as the time length of the sampling time interval, or the time length of the predetermined time interval is different from the time length of the sampling time interval.

9. A control device for a wind power generation unit, characterized in that, The control device includes: A statistical value calculation unit configured to periodically calculate the statistical value of the blade angle value measured by the encoder within a sampling time interval; A fluctuation determination unit configured to determine that the blade angle value measured by the encoder fluctuates in response to the calculated statistical values of a continuous multiple of sampling time intervals being greater than a predetermined threshold; A pitch control unit configured to perform a specific pitch operation in response to determining that the blade angle value measured by the encoder fluctuates, wherein the pitch control unit is further configured to: Calculate the first angle change amounts and values for each of the continuous multiple predetermined time intervals; Calculate the second angle change amounts and values for each of the continuous multiple predetermined time intervals; Compare the first angle change amounts and values and the second angle change amounts and values for each predetermined time interval; In response to the comparison result indicating that the first angle change amounts and values and the second angle change amounts and values for each predetermined time interval are all consistent, stop the consistency adjustment operation of the blade angle, wherein each predetermined time interval includes a plurality of sampling times, and each sampling time interval includes a plurality of sampling times.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the control method of the wind turbine generator set according to any one of claims 1 to 8.

11. A controller, characterized in that, The controller includes: A processor; and A memory storing a computer program, which when executed by the processor, implements the control method of the wind turbine generator set according to any one of claims 1 to 8.

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