Pitch control methods and systems for wind turbine generators

Abstract

A pitch control method and system for a wind turbine generator set are provided. The method includes: when the wind turbine generator set is shut down, verifying the blade shutdown angle to the first preset angle based on the initial reading of an encoder and the first preset angle, wherein the encoder reading is used to determine the blade angle of the wind turbine generator set; after the wind turbine generator set is started up, determining whether the blade angle has reached a second preset angle during the process of the wind turbine generator set running from the blade shutdown angle to the 0-degree position; when it is determined that the blade angle has reached the second preset angle, causing the encoder to be hardware-zeroed. Through the pitch control method and system of this disclosure, automatic hardware zeroing of the encoder can be achieved without affecting the normal operation of the wind turbine generator set.

Description

Technical Field

[0001] This invention relates to the field of wind power, and more specifically, to a pitch control method and system for wind turbine generator sets. Background Technology

[0002] With the gradual expansion of wind turbine scale and the increasing sophistication of turbine safety protection, the power generation performance of wind turbines (i.e., improving the power generation and availability of wind turbines) has received increasing attention. How to fully utilize wind energy and obtain maximum energy and economic benefits has become a crucial issue that the main control system of wind turbines must address.

[0003] Wind turbine generators are equipped with pitch control systems. These systems determine whether the wind turbine is operating normally by checking if the blade angles have reached the expected angles, thus ensuring the safe use of the blades and the stable operation of the generator. Encoders are typically used in the pitch control system to assist in detecting blade angles. To ensure accurate blade angle measurement, the blades need to be calibrated to the 0-degree position before the wind turbine generator is put into operation. The current method for calibrating the blade 0-degree position is as follows: maintenance personnel switch the pitch control cabinet to manual mode and manually rotate the pitch control system to rotate the blades to the 0-degree mark. Then, a hardware switch is used to zero the encoder.

[0004] When operating the propellers during the maintenance of a wind turbine, it is generally required that only one blade be operated at a time. That is, only one blade is allowed to be operated to the 0-degree position at a time. If the next blade needs to be operated, the blade that was previously operated to the 0-degree position must first be feathered to the 90-degree position to ensure the safe operation of the wind turbine.

[0005] However, to reduce system costs and minimize the number of data transfer links in communication with the main controller, and to standardize the design of the pitch control cabinets for the three shafts of the wind turbine generator to reduce design and manufacturing costs, most pitch control systems currently lack a main CPU (i.e., a single main CPU module centrally controls all three pitch control cabinets). The advantage of this is that it achieves independence for the three pitch control cabinets, eliminating concerns about safety hazards caused by main CPU module failure or damage. However, without a main CPU, manual operation control of the three pitch control cabinets cannot be implemented in the program logic. Therefore, a forced manual mode is added to the pitch control system to allow each of the three blades to open sequentially, while the manual knob, together with the manual control knob, ensures the reliability of the manual mode.

[0006] In this situation, single-blade pitch control requires strict adherence and execution by maintenance personnel. However, due to the following reasons, it frequently occurs in wind farms that all three blades of the pitch system simultaneously engage at the 0-degree position, even leading to wind turbine overspeed and tower collapse accidents:

[0007] (1) When personnel change positions or move around, safety training is not provided accordingly.

[0008] (2) The maintenance personnel are not familiar with the aerodynamic performance and operating procedures of the wind turbine.

[0009] (3) The maintenance personnel had a certain sense of complacency, such as the wind was very light at the time, and they subjectively believed that there would be no danger even if all three blades were opened to 0 degrees.

[0010] However, because wind speed is instantaneous and unpredictable, sudden increases in wind speed or even gusts often occur, leading to safety accidents.

[0011] In addition to the aforementioned safety hazards, since manual propeller opening can only be performed for a certain period of time each time, and the drive will automatically stop outputting after the time is up, it is necessary to repeatedly operate the manual knob switch to open the blade from the stop position to 0 degrees. If there are three blades and multiple units, this work will also take a long time. Summary of the Invention

[0012] In order to at least solve the above-mentioned problems in the prior art, this application provides a pitch control method and system for wind turbine generator sets.

[0013] According to one aspect of the present invention, a pitch control method for a wind turbine generator set is provided. The method includes: when the wind turbine generator set is shut down, verifying the blade shutdown angle to the first preset angle based on the initial reading of an encoder and a first preset angle, wherein the encoder reading is used to determine the blade angle of the wind turbine generator set; after the wind turbine generator set is started up, determining whether the blade angle has reached a second preset angle during the process of the wind turbine generator set running from the blade shutdown angle to the 0-degree position; when it is determined that the blade angle has reached the second preset angle, causing the encoder to be hardware-zeroed.

[0014] Optionally, the step of verifying the blade stopping angle to the first preset angle based on the initial reading of the encoder and the first preset angle may include: determining a reference value for the encoder based on the initial reading and the first preset angle, wherein the blade angle of the wind turbine is calculated by dividing the difference obtained by subtracting the reference value from the reading of the encoder by the pitch system transmission ratio.

[0015] Optionally, the step of determining whether the blade angle has reached the second preset angle during the process of the wind turbine generator set running from the blade stop angle to the 0-degree position may include: determining whether the blade angle has reached the second preset angle by using a position sensor, and further determining whether the angle obtained by dividing the difference by the pitch system transmission ratio is equal to the second preset angle.

[0016] Optionally, the method may further include: after verifying the blade stopping angle to the first preset angle, performing anti-overflow processing on the encoder, wherein the anti-overflow processing may include: when the difference is greater than half of the maximum reading of the encoder, determining the angle of the wind turbine blade by dividing the value obtained by subtracting the maximum reading of the encoder from the difference by the pitch system transmission ratio; or when the difference is less than a negative value of half of the maximum reading of the encoder, determining the angle of the wind turbine blade by dividing the value obtained by adding the maximum reading of the encoder to the difference by the pitch system transmission ratio.

[0017] According to another aspect of the present invention, a pitch control system for a wind turbine generator set is provided, characterized in that the system comprises: an encoder, the reading of which is used to determine the blade angle of the wind turbine generator set; a PLC module configured to be electrically connected to the encoder; and a controller configured to perform the following operations: when the wind turbine generator set is shut down, obtaining an initial reading of the encoder and verifying the blade shutdown angle to the first preset angle based on the initial reading and a first preset angle; after the wind turbine generator set is started up, determining whether the blade angle has reached a second preset angle during the process of the wind turbine generator set running from the blade shutdown angle to the 0-degree position; when it is determined that the blade angle has reached the second preset angle, controlling the PLC module to output a zeroing signal to the encoder to cause the encoder to perform hardware zeroing.

[0018] The controller can be configured to determine a reference value for the encoder based on the initial reading and the first preset angle, wherein the controller can calculate the blade angle of the wind turbine by dividing the difference obtained by subtracting the reference value from the encoder reading by the pitch system transmission ratio.

[0019] The system may further include: a position sensor configured to detect whether the blade angle has reached the second preset angle, wherein the sensing element of the position sensor may be mounted on one of the blade hub and the bearing, and the triggering element of the position sensor may be mounted on the other of the blade hub and the bearing.

[0020] Optionally, the controller may also be configured to determine whether the blade angle has reached the second preset angle by determining whether the angle obtained by dividing the difference by the pitch system gear ratio is equal to the second preset angle.

[0021] According to another aspect of the present invention, a computer-readable storage medium is provided, characterized in that the computer-readable storage medium stores computer program instructions, which, when executed by a processor, implement a pitch control method for a wind turbine generator set.

[0022] According to another aspect of the present invention, a computer device is provided, comprising a readable medium storing computer program instructions, characterized in that the computer program instructions include instructions for performing the aforementioned pitch control method for a wind turbine generator set.

[0023] Beneficial effects

[0024] By applying the pitch control system and method for wind turbine generators according to exemplary embodiments of the present invention, automatic zeroing of the encoder can be achieved, eliminating the workload of manual zeroing. Furthermore, after hardware zeroing of the encoder and updating the PLC module program, no personnel are required to log into the hub to re-verify the angle; that is, after the PLC module program update, the encoder output position remains the correct stopping position. In addition, hardware zeroing can be set at the 0-degree position of the blade, meaning the actual blade position is close to 0 degrees. Therefore, zeroing can be performed during wind turbine generator operation, simultaneously setting the reference value used by the encoder to calculate the blade angle to 0, without affecting the normal operation of the wind turbine. On the other hand, since the wind turbine's operation requires the pitch to reach 0 degrees upon startup to generate electricity, reaching 0 degrees is a necessary state, thus hardware zeroing of the encoder can be achieved within a very short period. Attached Figure Description

[0025] These and / or other aspects and advantages of the present invention will become clearer and more readily understood from the following detailed description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This is a block diagram illustrating a pitch control system for a wind turbine generator according to an exemplary embodiment of the present invention.

[0027] Figure 2 This is a flowchart illustrating a pitch control method for a wind turbine generator according to an exemplary embodiment of the present invention.

[0028] Figures 3(a) to 3(c) This shows the encoder working properly.

[0029] Figures 4(a) and 4(b) illustrate the situation of encoder data overflow.

[0030] Figure 5 This is a schematic diagram illustrating a blade position detection structure according to an exemplary embodiment of the present invention.

[0031] Figure 6 A schematic diagram of the electrical control for hardware reset according to an exemplary embodiment of the present invention is shown.

[0032] The invention will be described in detail below with reference to the accompanying drawings, throughout which the same or similar elements will be indicated by the same or similar reference numerals. Detailed Implementation

[0033] The following description, taken with reference to the accompanying drawings, is provided to aid in a full understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. The description includes various specific details to aid understanding, but these details are considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Furthermore, descriptions of known functions and constructions may be omitted for clarity and brevity.

[0034] Figure 1 This is a block diagram illustrating a pitch control system 100 for a wind turbine generator set according to an exemplary embodiment of the present invention.

[0035] Reference Figure 1 According to an exemplary embodiment of the present invention, the pitch control system 100 of a wind turbine generator set may include an encoder 110, a PLC module 120, and a controller 130.

[0036] In an exemplary embodiment of the present invention, the readings of encoder 110 can be used to determine the blade angle of a wind turbine generator set. PLC module 120 can be electrically connected to encoder 110, and controller 130 can perform pitch control of the wind turbine generator set and control PLC module 120 to output a zeroing signal to encoder 130 to perform hardware zeroing of encoder 110. This will be discussed in conjunction with... Figures 2 to 6 This will be explained in detail.

[0037] Figure 2 This is a flowchart illustrating a pitch control method for a wind turbine generator according to an exemplary embodiment of the present invention.

[0038] like Figure 2As shown, when the wind turbine generator is shut down, the controller 130 can verify the blade shutdown angle to the first preset angle based on the initial reading of the encoder 110 and the first preset angle (step S210). When the encoder 110 is initially installed or used for the first time, the initial reading of the encoder may be arbitrary. The blade angle calculated directly using this initial reading may not be consistent with the actual blade angle. Therefore, it is necessary to verify the blade angle so that the blade angle can be correctly detected based on the encoder reading during the subsequent operation of the wind turbine generator.

[0039] In an exemplary embodiment of the present invention, the first preset angle can be a preset stopping position, such as 87 degrees, 89 degrees, 91 degrees, etc. Hereinafter, 87 degrees will be used as an example for explanation. Step S210 can be triggered using a proximity switch such as an 87-degree proximity switch. That is, when the 87-degree proximity switch is triggered, the verification operation of step S210 can be performed.

[0040] In an exemplary embodiment of the present invention, step S210 can be performed using software verification. Specifically, the encoder 110 typically obtains the blade angle using the following expression 1:

[0041]

Expression 1

[0042] Blade angle = (encoder reading - reference value) / pitch system gear ratio

[0043] Here, the pitch system transmission ratio refers to the mechanical transmission ratio between the pitch motor and the blades. It can be the ratio of the angular velocities of the two rotating components in the mechanism, also known as the speed ratio, and in the exemplary embodiments of the present invention, it can be a known value. Furthermore, when the blade angle changes during the operation of the wind turbine generator set, the reading of the encoder 110 also changes accordingly, and the change in the encoder 110 reading reflects the change in blade angle.

[0044] As can be seen from Expression 1, the blade angle can be verified by checking the reference value. That is, since the blade angle calculated by the reading of encoder 110 is related to the reference value, the calculated blade angle can be made consistent with the actual blade angle by adjusting the corresponding reference value.

[0045] Therefore, based on expression 1, the following expression 2 can be derived to obtain the reference value:

[0046]

Expression 2

[0047] Reference value = Encoder reading - Blade angle * Pitch system transmission ratio

[0048] Based on Expression 2, the controller 130 can determine a reference value for the encoder 110 based on the initial reading of the encoder 110 and a first preset angle (e.g., 87 degrees) (i.e., reference value = initial encoder reading - 87 degrees * pitch system transmission ratio). Using this determined reference value, even if the initial reading of the encoder 110 is arbitrary when the wind turbine is shut down, the blade angle calculated based on the initial reading (i.e., the blade stopping angle when the wind turbine is shut down) can be made consistent with the first preset angle, thereby achieving the verification of the stopping position (i.e., 87-degree position verification).

[0049] After completing the 87-degree position verification, since only a reference value is obtained but the encoder 110 is not hardware zeroed, encoder data may overflow during the operation of the wind turbine generator after startup, causing angle jumps. Therefore, optionally, in an exemplary embodiment of the present invention, encoder overflow prevention processing can also be performed after step S210 is completed. The following refers to... Figures 3(a) to 3(b) This will be explained in detail.

[0050] Figures 3(a) to 3(c) The diagram shows the encoder 110 operating normally. Figures 4(a) and 4(b) show the encoder data overflow situation.

[0051] According to expression (1), in the three cases from 3(a) to 3(c), the angle can be calculated directly according to expression (1). That is, the distance and direction indicated by the arrow in the figure are divided by the transmission ratio of the pitch system to obtain the actual position angle. Figures 3(a) and 3(c) show positive changes (positive values, the encoder reading gets larger and larger), while Figure 3(b) shows negative changes (negative values, the encoder reading gets smaller and smaller).

[0052] However, after the encoder 110 rotates to its maximum value, it will change from the maximum value to 0. The formula for calculating the angle of the encoder 110 is expression (1). Therefore, after the encoder 110 reaches its maximum value, an angle jump phenomenon will occur. Specifically, referring to Figures 4(a) and 4(b), when the reference value is near the maximum value or 0, since the count value will change back to 0 after the encoder 110 reading reaches the maximum value, if the calculation is still performed by substituting "encoder reading - reference value" into expression (1), the calculated change distance will be the distance indicated by the arrow in Figure 4(a), and the direction will also be incorrect, resulting in a data jump and causing an angle jump. The actual change distance is the sum of distance 1 and distance 2 in Figure 4(b). If the initial reading position of the encoder 110 is not set properly in step S210, the reference value position will be located near the maximum value or 0, making it easier to cause an angle jump.

[0053] Therefore, in an exemplary embodiment of the present invention, the controller 130 may perform overflow prevention as follows:

[0054] When the difference between the encoder reading and the reference value is greater than the maximum reading C of encoder 110... max (That is, half of the maximum value in Figures 4(a) to 4(b)) (that is, greater than C) max When / 2), the angle obtained by dividing the value obtained by subtracting the maximum reading of encoder 110 from the difference by the pitch system transmission ratio is determined as the blade angle of the wind turbine generator, instead of directly using expression 1.

[0055] Furthermore, similarly, when the difference between the encoder reading and the reference value is less than half the negative value of the maximum reading of the encoder 110 (i.e., less than -C), the error will also occur. max When / 2), the angle obtained by dividing the value obtained by adding the maximum reading of the encoder 110 to the difference by the pitch system transmission ratio is determined as the blade angle of the wind turbine generator, instead of directly using expression 1.

[0056] It should be understood that the specific operation of the overflow prevention processing of encoder 110 is not limited to this, and various other methods can be used to achieve it, as long as the angle jump can be prevented.

[0057] Return to reference Figure 2 After the blade stopping angle verification is completed as described above, after the wind turbine generator is started, the controller 130 can determine whether the blade angle has reached the second preset angle (step S220) during the process of the wind turbine generator running from the blade stopping angle (e.g., 87 degrees) to the 0-degree position. In an exemplary embodiment of the present invention, the second preset angle can be the 0-degree position, or it can be any other angle position between the 87-degree position and the 0-degree position. In the following description, for ease of explanation, the 0-degree position will be used as an example.

[0058] In an exemplary embodiment of the present invention, a position sensor can be used to detect whether the blade angle has reached a second preset angle. The sensing component of the position sensor can be installed on one of the blade hub and the bearing, and the triggering component of the position sensor can be installed on the other of the blade hub and the bearing.

[0059] For example, a position sensor can be a sensor for detecting a 0-degree position. This sensor can achieve the detection of the 0-degree position by consisting of a sensing element and a triggering element. The sensing element can be implemented as a proximity switch, and the triggering element can be implemented as a component that triggers the proximity switch. The position sensor can be positioned as follows: Figure 5 The blade position detection structure shown.

[0060] Figure 5 This is a schematic diagram illustrating a blade position detection structure according to an exemplary embodiment of the present invention.

[0061] Figure 5 The blade position detection structure shown may include a reducer 101, a transmission wheel 102, a tension wheel 103, a tension wheel 104, a hub 105, a toothed belt 106, a blade mounting device 107 (specifically referring to the pitch bearing and the components connected and fixed to the pitch bearing), a toothed belt fixing block 108, a toothed belt fixing block 109, a tension wheel fixing device 113, a 5-degree proximity switch 110, an 87-degree proximity switch 111, a stop block 112, and a 0-degree proximity switch 201.

[0062] The reducer 101 meshes with a pitch motor (not shown). The drive pulley 102 is mechanically connected to the output shaft of the reducer 101. The reducer 101 and the tensioner fixing device 113 are both fixedly mounted on the hub 105, and the tensioner fixing device 113 is used to mount tensioners 103 and 104. Tensioners 103 and 104 are used to tension the toothed belt 106 to ensure reliable transmission. A 5-degree proximity switch 110 and an 87-degree proximity switch 111 are mounted on the hub 105, with the 5-degree proximity switch 110 mounted at the 5-degree position of the blade and the 87-degree proximity switch 111 mounted at the 87-degree position of the blade. A stop block 112 is mounted on the blade mounting device 107 and rotates with the blade mounting device 107.

[0063] The blade mounting device 107 is a ring-shaped mechanical mechanism used to mount blades. A toothed belt 106 runs along and is in close contact with the side of the blade mounting device 107, providing power for transmission. A toothed belt fixing block 109 and a tensioning wheel fixing device 110 are used to fix the toothed belt 106 to the blade mounting device 107.

[0064] When pitch adjustment (i.e., changing the blade pitch angle) is required, the pitch motor (not shown) drives the reducer 101 to rotate. The reducer 101 drives the drive pulley 102 to rotate, and the rotation of the drive pulley 102 drives the toothed belt 106 to move. The toothed belt 106 drives the blade mounting device 107 to rotate, thereby changing the angle of the wind turbine blades and achieving the purpose of adjusting the pitch angle. When the angle measured by the encoder is near 5 degrees, and the stop block 112 rotates to the position of the 5-degree proximity switch 110 and triggers the 5-degree proximity switch 110, the pitch system considers the blade position to be correct. When the blade angle measured by the encoder is near 5 degrees, but the proximity switch 110 is not triggered, the pitch system considers an abnormality to have occurred, triggers a fault, and causes the wind turbine to feather and stop. Similarly, when the blade angle measured by the encoder is around 87 degrees, and the stop block 112 rotates to the position of the 87-degree proximity switch 111 and triggers the 5-degree proximity switch 111, the pitch system considers the blade position to be correct. However, when the blade angle measured by the encoder is around 87 degrees, but the proximity switch 111 is not triggered, the pitch system considers an abnormality to have occurred.

[0065] Reference Figure 5 A 0-degree proximity switch 201 can be further provided on the hub 105 as the sensing component of the position sensor used in step S220. This proximity switch 201 is located on the actual 0-degree position scale line of the blade. When the stop block 112 (which can serve as the triggering component of the position sensor) rotates to the position of the 0-degree proximity switch 201, the controller 220 determines that the 0-degree proximity switch 201 is in a triggered state by the stop block 112. Preferably, the sensor type of the proximity switch 201 can be set to normally open, that is, when the stop block 112 is not triggered, the output signal of the proximity switch 201 is low; after the stop block 112 is triggered, the output signal of the proximity switch 201 is high. However, this application is not limited to this; the sensor type of the proximity switch 201 can also be set to normally closed, that is, when the stop block 112 is not triggered, the output signal of the proximity switch 201 is high; after the stop block 112 is triggered, the output signal of the proximity switch 201 is low.

[0066] Optionally, in addition to using a hardware proximity switch to detect whether the second preset angle has been reached, in an exemplary embodiment of the present invention, the blade angle can also be calculated using Expression 1 based on the encoder reading. When both the proximity switch and encoder reading verify that the blade angle has reached the second preset angle, it can be determined that the blade angle has reached the second preset angle. This ensures the accuracy of the blade position.

[0067] Optionally, to further ensure the accuracy of the blade position during verification, before confirming whether the blade angle has reached the second preset angle, it can also be determined whether the wind turbine generator set experienced an angle jump during startup (e.g., blade angle jump caused by various errors or faults during startup) based on the angle calculated using encoder readings. When no angle jump occurs (or the signal recovers after a short jump) and the angles of the three blades of the wind turbine generator set are consistent and close to 0 degrees (e.g., the difference from 0 degrees is less than a predetermined threshold (e.g., 0.5 degrees)), the above step S220 can be performed. Here, the purpose of determining that the three blades of the wind turbine generator set are consistent and close to 0 degrees is: if only the angle of one blade is judged, it is possible that due to factors such as faults, the actual blade angle of that blade may not reach 0 degrees, but it may be detected as reaching 0 degrees by the encoder or proximity switch. By verifying the angles of the three blades, this situation can be prevented.

[0068] Furthermore, although a 0-degree proximity switch is added in the exemplary embodiment of the present invention to realize the detection of the second preset angle, the present application is not limited thereto. The second preset angle can also be any angle between the blade stopping angle (e.g., 87 degrees) and 0 degrees, and a corresponding position sensor can be added or an installed position sensor capable of detecting the arbitrary angle can be used to detect the arbitrary angle.

[0069] Subsequently, when it is determined that the blade angle has reached the second preset angle, the controller 130 can control the encoder 110 to perform hardware zeroing (step S230).

[0070] Figure 6 An example hardware reset electrical control structure according to an exemplary embodiment of the present invention is shown.

[0071] like Figure 6 As shown, the hardware reset electrical control structure includes a PLC module 601 (corresponding to...). Figure 1 PLC module 120), reset signal line 602, encoder 603 (corresponding to Figure 1 The encoder 110 and power supply 603 are connected. One end of the reset signal line 602 is electrically connected to the DO output port of the PLC module 601, and the other end is electrically connected to the reset port of the encoder 603. The PLC module 601 can receive signals from the proximity switch 201 to determine whether the proximity switch 201 has been triggered.

[0072] When controller 130 detects Figure 5When the 0-degree proximity switch 201 is triggered, the angles of all three blades of the wind turbine are close to 0 degrees, and the "verification complete" flag in the PLC module 601 is 1 (this flag being 1 indicates that the 0-degree position verification is complete), the controller 130 can control the DO digital output port of the PLC module 601 to output a high-level signal (e.g., a 24V signal). Upon receiving the high-level signal, the encoder 603 will automatically zero the encoder hardware. Furthermore, after the hardware zeroing is complete, the controller 130 can set the reference value of the encoder 110 to 0 to ensure the accuracy and continuous, non-jumping blade angle calculated based on the encoder 110 readings. It can also set the "zeroing complete" flag so that hardware zeroing is no longer required when the wind turbine is started.

[0073] By applying the pitch control system and method for wind turbine generators according to exemplary embodiments of the present invention, automatic zeroing of the encoder can be achieved, eliminating the workload of manual zeroing. Furthermore, after hardware zeroing of the encoder and updating the PLC module program, no personnel are required to log into the hub to re-verify the angle; that is, after the PLC module program update, the encoder output position remains the correct stopping position. In addition, hardware zeroing can be set at the 0-degree position of the blade, meaning the actual blade position is close to 0 degrees. Therefore, zeroing can be performed during wind turbine generator operation, simultaneously setting the reference value used by the encoder to calculate the blade angle to 0, without affecting the normal operation of the wind turbine. On the other hand, since the wind turbine's operation requires the pitch to reach 0 degrees upon startup to generate electricity, reaching 0 degrees is a necessary state, thus hardware zeroing of the encoder can be achieved within a very short period.

[0074] The pitch control method for a wind turbine generator according to an exemplary embodiment of the present invention can be implemented by computer program instructions recorded on a computer-readable storage medium, which implement the method when executed by a processor or other type of computing device. The storage medium may also include program instructions, data files, data structures, etc., or a combination of data files, data structures, etc., and program instructions. Examples of computer-readable storage media include magnetic media (e.g., hard disks, floppy disks, and magnetic tapes), optical media (e.g., CD-ROMs and DVDs), magneto-optical media (e.g., optical discs), and hardware devices specifically configured to store and execute program instructions (e.g., read-only memory (ROM), random access memory (RAM), flash memory, etc.). Examples of program instructions include (e.g., machine code generated by a compiler) and files containing higher-level code that can be executed by a computer using an interpreter. The described hardware device can be configured as one or more software units to perform the above operations and methods, and vice versa. Furthermore, the computer-readable storage medium can be distributed across computer systems connected via a network, and the computer-readable code or program instructions can be stored and executed in a distributed manner.

[0075] For example, according to an exemplary embodiment of this application, a computer-readable storage medium storing instructions can be provided, wherein when the instructions are executed by at least one computing device, the at least one computing device causes the at least one computing device to perform the following steps: when the wind turbine is shut down, verifying the blade shutdown angle to the first preset angle based on the initial reading of the encoder and the first preset angle, wherein the encoder reading is used to determine the blade angle of the wind turbine; after the wind turbine is started up, determining whether the blade angle has reached a second preset angle during the process of the wind turbine running from the blade shutdown angle to the 0-degree position; when it is determined that the blade angle has reached the second preset angle, causing the encoder to be hardware zeroed.

[0076] The instructions stored in the aforementioned computer-readable storage medium can be executed in environments deployed in computer devices such as clients, hosts, agent devices, and servers. It should be noted that the instructions can also be used to perform additional steps beyond those described above, or to perform more specific processing while executing the above steps. The details of these additional steps and further processing are already provided in the reference... Figures 1 to 6 As mentioned in the description of the relevant systems and methods, they will not be repeated here to avoid repetition.

[0077] On the other hand, when Figure 1When the systems and apparatus shown are implemented as software, firmware, middleware, or microcode, the program code or code segment used to perform the corresponding operation can be stored in a computer-readable medium such as a storage medium, such that at least one processor or at least one computing device can perform the corresponding operation by reading and running the corresponding program code or code segment.

[0078] For example, according to an exemplary embodiment of this application, a computer device including a readable medium storing computer program instructions may be provided, wherein the instructions, when executed by at least one computing device, cause the at least one computing device to perform the following steps: when a wind turbine is shut down, verifying the blade shutdown angle to the first preset angle based on an initial encoder reading and a first preset angle, wherein the encoder reading is used to determine the blade angle of the wind turbine; after the wind turbine is started up, determining whether the blade angle has reached a second preset angle during the process of the wind turbine running from the blade shutdown angle to the 0-degree position; when it is determined that the blade angle has reached the second preset angle, causing the encoder to perform hardware zeroing.

[0079] Although the invention has been specifically shown and described with reference to exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the claims.

Claims

1. A method of pitch control of a wind turbine, characterized in that, The method comprises: verifying a blade shutdown angle to a first preset angle based on an initial reading of an encoder and the first preset angle when a wind turbine is shut down, wherein the reading of the encoder is used to determine a blade angle of the wind turbine; determining whether the blade angle reaches a second preset angle during a process in which the wind turbine runs from the blade shutdown angle to a 0-degree position after the wind turbine is started up; causing the encoder to perform a hardware zero-clearing when it is determined that the blade angle reaches the second preset angle, wherein the step of verifying the blade shutdown angle to the first preset angle based on the initial reading of the encoder and the first preset angle comprises: determining a reference value for the encoder based on the initial reading and the first preset angle, wherein the reference value is calculated by subtracting a product of the first preset angle and a pitch system transmission ratio from the initial reading, wherein the blade angle of the wind turbine is calculated by dividing a difference between the reading of the encoder and the reference value by the pitch system transmission ratio.

2. The method of claim 1, wherein, The step of determining whether the blade angle reaches the second preset angle during a process in which the wind turbine runs from the blade shutdown angle to a 0-degree position after the wind turbine is started up comprises: determining, by a position sensor, whether the blade angle reaches the second preset angle, and further determining whether an angle calculated by dividing the difference by the pitch system transmission ratio is equal to the second preset angle.

3. The method of claim 1, wherein, The method further comprises: performing an anti-overflow process on the encoder after verifying the blade shutdown angle to the first preset angle, wherein the anti-overflow process comprises: when the difference is greater than half of a maximum reading of the encoder, determining an angle obtained by dividing a value obtained by subtracting the maximum reading of the encoder from the difference by the pitch system transmission ratio as the blade angle of the wind turbine; or when the difference is less than a negative value of half of the maximum reading of the encoder, determining an angle obtained by dividing a value obtained by adding the maximum reading of the encoder to the difference by the pitch system transmission ratio as the blade angle of the wind turbine.

4. A variable pitch control system for a wind turbine generator system, characterized by, The system comprises: an encoder, a reading of which is used to determine a blade angle of a wind turbine; a PLC module configured to be electrically connected with the encoder; a controller configured to: obtain an initial reading of the encoder and verify a blade shutdown angle to a first preset angle based on the initial reading and the first preset angle when a wind turbine is shut down; determine whether the blade angle reaches a second preset angle during a process in which the wind turbine runs from the blade shutdown angle to a 0-degree position after the wind turbine is started up; control the PLC module to output a zero-clearing signal to the encoder to cause the encoder to perform a hardware zero-clearing when it is determined that the blade angle reaches the second preset angle, wherein the controller is configured to: determine a reference value for the encoder based on the initial reading and the first preset angle, wherein the reference value is calculated by subtracting a product of the first preset angle and a pitch system gear ratio from the initial reading, wherein the blade angle of the wind turbine generator is calculated by dividing a difference between the reading from the encoder and the reference value by the pitch system gear ratio.

5. The system of claim 4, wherein, The system further comprises a position sensor configured to detect whether the blade angle reaches the second preset angle, wherein a sensing part of the position sensor is mounted on one of a hub and a bearing of the blade, and a triggering part of the position sensor is mounted on the other of the hub and the bearing of the blade.

6. The system of claim 4, wherein, The controller is further configured to determine whether the blade angle reaches the second preset angle by determining whether an angle calculated by dividing the difference by the pitch system gear ratio is equal to the second preset angle.

7. A computer readable storage medium characterized in that, The computer readable storage medium has stored thereon computer program instructions which, when executed by a processor, implement the method of any one of claims 1-3.

8. A computer device comprising a readable medium having stored computer program instructions, characterized in that, The computer program instructions comprise instructions for performing the method of any one of claims 1-3.

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