CN115875199A - Variable pitch control method and variable pitch controller of wind generating set - Google Patents

Abstract

A pitch control method and a pitch controller of a wind generating set are disclosed. The pitch control method comprises the following steps: responding to the condition that the wind generating set is in a variable pitch state, and determining whether the variable pitch direction at the current control moment is consistent with the variable pitch direction at the previous control moment; in response to the fact that the pitch variation direction at the current control moment is consistent with the pitch variation direction at the previous control moment, correcting the given pitch variation speed at the current control moment based on the given pitch variation speed at the current control moment, the given pitch variation speed at the previous control moment and a preset correction coefficient; and controlling the variable pitch motor to perform variable pitch operation based on the corrected given variable pitch speed.

Description

Variable pitch control method and variable pitch controller of wind generating set

Technical Field

The present disclosure relates generally to the field of wind power generation, and more particularly, to a pitch control method and a pitch controller of a wind turbine generator system.

Background

Because wind energy is low-density energy and has the characteristics of instability and randomness, the control technology of the wind driven generator is the key for the safe and efficient operation of the wind driven generator. The key of popularization and application of wind power generation is to develop a wind power generator system and an advanced control technology which are suitable for wind power conversion, reliable in operation, high in efficiency and good in control performance and power supply performance.

With the increase in the capacity of wind turbines, pitch control has become the mainstream control method for wind turbines. Considering from the aerodynamic perspective, when the wind speed is too high, the power output of the wind driven generator can be kept stable only by adjusting the pitch angle and changing the attack angle of the airflow to the blades so as to change the aerodynamic torque obtained by the wind driven generator set; according to the Betz theory, if the position of the propeller pitch angle is over-adjusted, the wind driven generator can not absorb the maximum wind energy, and even the rotating speed of the wind driven generator is unstable; if the response time of the adjustment of the pitch angle is too slow, the wind driven generator can not execute pitch variation according to the control command in time, and the wind driven generator can not absorb the maximum wind energy, even the rotating speed of the wind driven generator is over-speed. In addition, in the feathering process of the wind driven generator, if the position is overshot, a limit switch can be triggered possibly, or the position of a blade is vibrated when the wind driven generator is shut down, so that the service life of a variable pitch motor is influenced.

Therefore, the method has the advantages that the variable pitch control of the wind generating set is optimized, and the method plays an important role in stable operation and improvement of the generating capacity of the wind generating set.

Disclosure of Invention

The embodiment of the disclosure provides a variable pitch control method and a variable pitch controller of a wind generating set, which can enable the actual variable pitch speed of a variable pitch system to be more adaptive to the change of wind speed, particularly to the change of the rotating speed of a wind driven generator, and further enable the wind generating set to operate more stably.

In one general aspect, there is provided a pitch control method of a wind turbine generator set, the pitch control method comprising: responding to the condition that the wind generating set is in a variable pitch state, and determining whether the variable pitch direction at the current control moment is consistent with the variable pitch direction at the previous control moment; in response to the fact that the pitch variation direction at the current control moment is consistent with the pitch variation direction at the previous control moment, correcting the given pitch variation speed at the current control moment based on the given pitch variation speed at the current control moment, the given pitch variation speed at the previous control moment and a preset correction coefficient; and controlling a variable pitch motor to perform variable pitch operation based on the corrected given variable pitch speed.

In another general aspect, there is provided a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a pitch control method as described above.

In another general aspect, there is provided a pitch controller, comprising: a processor; and a memory storing a computer program which, when executed by the processor, implements a pitch control method as described above.

In another general aspect, there is provided a wind park comprising a pitch controller as described above.

According to the pitch control method and the pitch controller of the wind generating set, through correcting the given pitch speed, the lag of pitch execution and the lag of the pitch execution on the wind speed change caused by communication data transmission can be made up, so that the pitch execution of a pitch system is more matched with the actual rotating speed of the wind generating set, and the pitch response speed and the operation stability of the wind generating set are improved.

Drawings

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 accompanying drawings illustrating embodiments, in which:

FIG. 1 is a diagram illustrating an example of wind generator speed and pitch speed during a pitch operation of a wind park;

FIG. 2 is a diagram illustrating another example of wind generator speed and pitch speed during a pitch operation of a wind park;

FIG. 3 is a flow chart illustrating a method of pitch control of a wind park according to an embodiment of the present disclosure;

FIG. 4 is a diagram illustrating the effect of a method of pitch control of a wind park according to an embodiment of the present disclosure;

fig. 5 is a block diagram illustrating a controller according to an embodiment of the present disclosure.

Detailed Description

The following detailed description is provided to assist the reader in obtaining a thorough understanding of the methods, devices, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and/or systems described herein will be apparent to those skilled in the art after reviewing the disclosure of the present application. For example, the order of operations described herein is merely an example, and is not limited to those set forth herein, but may be changed as will become apparent after understanding the disclosure of the present application, except to the extent that operations must occur in a particular order. Moreover, descriptions of features known in the art may be omitted for clarity and conciseness.

At present, a PID control mode is mainly adopted for pitch control of a wind turbine generator, that is, a master control system (master controller) of the wind turbine generator system calculates a pitch angle value and transmits a corresponding given pitch speed to a pitch system by using a constant rotation speed of the wind turbine generator as a control target, and the pitch system performs pitch control operation according to the latest given pitch speed. This method can achieve a constant control of the rotational speed of the wind turbine to some extent, but has the following disadvantages.

Firstly, because the wind speed is transient, the simple use of the PID control mode has certain limitation on the stabilizing effect of the rotating speed of the wind driven generator. Secondly, the PID control is based on a target difference value, namely the pitch control operation is started after the change of the rotating speed difference value of the wind driven generator is detected, so that the hysteresis is realized, and when the wind driven generator set operates above a rated wind speed, the fluctuation of the rotating speed of the wind driven generator can cause a large load, and the service life of the wind driven generator set is influenced. Thirdly, due to the hysteresis of the PID control, when the wind speed is suddenly increased, the phenomenon of over-speed of the wind driven generator is easy to occur, and the over-speed of the wind driven generator can cause two conditions, namely, the rotating speed of the generator is too high, the fatigue load of the wind driven generator set is increased, and the wind driven generator set is seriously worn and the service life is reduced when the wind driven generator set is operated at a high rotating speed for a long time; secondly, the generator is easy to trigger overspeed fault and stop due to overhigh rotating speed. Fourthly, because the PID control has the hysteresis, when the wind speed is suddenly reduced, the wind turbine generator system is easily and frequently switched between the power constant region and the rotating speed constant region, and the generator set is switched from the power constant region to the rotating speed constant region, so that the torque of the generator set is reduced, the generating efficiency is reduced, and the generating capacity of the generator set is influenced.

In order to realize accurate pitch control and reduce the hysteresis of pitch control execution on wind speed change, the current main method is to predict the wind speed or measure the wind speed in real time. However, the wind speed prediction is performed through the weather forecast information, and the predicted wind speed value is very inaccurate due to too high blindness, and is difficult to be used as a basis for pitch control. On the other hand, the wind speed sensor arranged in front is used for measuring wind, the installation of the sensor is limited because the variable-pitch hub rotates, and the addition of the slip ring equipment easily causes data interference and instability; if the wind speed sensor is mounted at the tail of the nacelle, it is required to measure a longer distance, resulting in a cost increase.

FIG. 1 is a diagram illustrating an example of wind generator speed and pitch speed during a pitch operation of a wind park.

Referring to fig. 1, curve 101 represents the wind turbine speed, curve 102 represents a given pitch speed, curve 103 represents the actual pitch speed performed by the pitch system, the abscissa represents time, and the ordinate represents the trend of the three curves, not the magnitude of the values of each other.

The principle of the variable pitch control is that the actual rotating speed and the target rotating speed of the wind driven generator are used as input, and the variable pitch speed required to be executed is calculated; when the actual rotating speed of the wind driven generator is higher than the target rotating speed, outputting positive speed to enable the blades to close; when the actual rotating speed of the wind driven generator is lower than the target rotating speed, negative speed is output, the blades are driven to be opened, and therefore the rotating speed of the wind driven generator stably runs near the target rotating speed.

However, the existing pitch control methods have the following disadvantages. After the rotating speed of the wind driven generator changes, the pitch speed required to be executed is calculated, so that the calculated pitch speed has certain hysteresis. On the other hand, because the data transmission between the main control system and the pitch control system of the wind generating set adopts a DP communication mode, the transmission period is generally 20ms, and the scanning periods of the main control system and the pitch control controller are also generally 20ms respectively, the given pitch control speed is calculated by the main control system, and the given pitch control speed is generally lagged by about 60ms until the pitch control controller executes the given pitch control speed. Due to the lag in pitch execution caused by the two factors, and the change in the rotational speed of the wind turbine caused by the wind speed transient, the pitch control cannot be matched with the rotational speed of the wind turbine in practice.

As shown in fig. 1, when the rotating speed of the wind driven generator (curve 101) increases at time t1, and then when the main control system detects that the rotating speed increases at time t2, the output given variable pitch speed (curve 102) starts to decrease; the master control system calculates the given variable pitch speed and sends the given variable pitch speed to the variable pitch system, however, due to the lag of communication data transmission, the variable pitch system can receive the given variable pitch speed at the time t3, and the given variable pitch speed is not the variable pitch speed matched with the rotating speed of the wind driven generator. Further, the pitch control system starts to perform the pitch control operation at the time t3, but the rotating speed of the corresponding wind driven generator is further increased, so that fluctuation or instability of the rotating speed of the generator is easily caused, and the power generation amount and the load of the wind driven generator set are further influenced.

FIG. 2 is a diagram illustrating another example of wind generator speed and pitch speed during a pitch operation of a wind park.

Referring to fig. 2, the abscissa represents the time value and the ordinate represents the variable value, wherein curve 201 represents the wind turbine rotational speed, curve 202 shows the given pitch speed and curve 203 represents the pitch speed actually performed by the pitch system. As shown in fig. 2, after the given pitch speed reaches the maximum value, the rotational speed of the wind turbine is still increased, and therefore, a certain pitch deviation occurs. At the same time, there is also a significant time difference between the actual executed pitch speed and the given pitch speed.

This situation cannot be solved by adjusting the PID parameters because: because the given variable pitch speed is based on the rotating speed of the wind driven generator, and the rotating speed of the wind driven generator is necessarily lagged behind the change of the wind speed, the PID parameter is changed, the response speed can be only increased, and the problem of the lag of variable pitch execution cannot be solved. On the other hand, the PID control is characterized in that when the PID parameter is increased, the response speed of the system can be increased, but the overshoot of the system is easily caused, and the stability of the rotating speed of the wind driven generator is not facilitated.

Therefore, according to the pitch control method of the wind generating set disclosed by the embodiment of the disclosure, the actual pitch speed of the pitch system is optimized by utilizing the speed change characteristic of PID control and the communication data transmission time difference between the master control system and the pitch system, so that the pitch is accelerated, the actual pitch speed of the pitch system is more adaptive to the change of the wind speed, particularly to the change of the rotating speed of the wind generating set, and the operation of the wind generating set is more stable.

FIG. 3 is a flow chart illustrating a method of pitch control of a wind park according to an embodiment of the present disclosure. The variable pitch control method can be realized in a variable pitch controller of the wind generating set, and also can be realized in a main controller or other special controllers of the wind generating set.

Referring to fig. 3, in step S301, in response to the wind turbine generator set being in the pitch state, it may be determined whether a pitch direction at a current control time is consistent with a pitch direction at a previous control time. Here, the current control time may be an nth time to an N + M time during the pitch operation, where N is an integer greater than 1 and M is an integer greater than or equal to 1. If the pitch control method is performed during the entire pitch operation, the N + M th moment in the process of the pitch operation may be a moment before the end of the pitch operation.

According to the embodiment of the disclosure, whether the pitch direction at the current control moment is consistent with the pitch direction at the previous control moment can be determined according to the given pitch speed at the current control moment and the given pitch speed at the previous control moment. Specifically, if the given pitch speed at the current control time and the given pitch speed at the previous control time are both positive values or negative values, it may be determined that the pitch direction at the current control time is consistent with the pitch direction at the previous control time, or it may be determined that the pitch direction at the current control time is inconsistent with the pitch direction at the previous control time.

In response to that the pitch direction at the current control time is consistent with the pitch direction at the previous control time, in step S302, the given pitch speed at the current control time may be corrected based on the given pitch speed at the current control time, the given pitch speed at the previous control time, and a preset correction coefficient. In particular, the difference between a given pitch speed at a current control moment and a given pitch speed at a previous control moment may first be calculated. Thereafter, it may be determined whether the difference is less than a preset threshold. In response to the difference being less than a preset threshold, the given pitch speed at the current control time may be modified based on the given pitch speed at the current control time, the difference, and a preset correction coefficient. For example, the product of the difference and a preset correction factor may be calculated, and the sum of the given pitch speed at the current control moment and the product may be determined as the corrected given pitch speed. According to an embodiment of the present disclosure, the preset correction coefficient may be an integer greater than 1, a preferred value range is 2 to 5, and the preset threshold may be, for example, 6 degrees/second.

In step S303, the pitch motor may be controlled to perform a pitch operation based on the corrected given pitch speed. However, if the difference between the given pitch speed at the current control time and the given pitch speed at the last control time is greater than the preset threshold, the pitch control method may be exited, and the pitch motor may be controlled to perform the pitch operation based on the given pitch speed at the current time.

Optionally, in response to the pitch direction at the current control time not being consistent with the pitch direction at the previous control time, in step S304, the pitch motor may be controlled to perform a pitch operation based on the given pitch speed at the current control time. That is, when the pitch direction changes, the corrected given pitch speed does not need to be calculated, but the given pitch speed at the current control moment is directly used for performing the pitch operation. The pitch control method may then be re-executed.

The following describes a pitch control method of a wind turbine generator system according to an embodiment of the present disclosure with reference to specific data.

For example, during a pitch operation, assume that the given pitch speed at the current control moment is 1.151 degrees/second and the given pitch speed at the previous control moment is 1.123 degrees/second. Because the given variable pitch speeds at the two moments are positive values, the variable pitch directions at the two moments can be determined to be consistent, and the difference value of the given variable pitch speeds at the two moments is 0.021 degrees/second. If the preset correction factor is 4 (i.e. the given pitch speed is to be corrected for 4 cycles), the corrected given pitch speed is 1.151+0.021 + 4=1.235 degrees/sec.

For another example, during a pitch operation, assume that the given pitch speed at the current control time is 1.123 degrees/second and the given pitch speed at the previous control time is 1.151 degrees/second. Because the given variable pitch speeds at the two moments are positive values, the variable pitch directions at the two moments can be determined to be consistent, and the difference value of the given variable pitch speeds at the two moments is-0.021 degrees/second. If the preset modification factor is 4 (i.e. the given pitch speed is to be modified for 4 cycles), the modified given pitch speed is 1.123+ (-0.021 × 4) =1.039 degrees/sec.

Fig. 4 is a diagram illustrating the effect of a pitch control method of a wind park according to an embodiment of the present disclosure.

Referring to fig. 4, curve 401 represents the given pitch speed, curve 402 represents the original actual pitch speed, curve 403 represents the modified given pitch speed, the abscissa represents time and the ordinate represents the value of the pitch speed only. As shown in fig. 4, curve 401 has a large clock deviation from curve 402, while curve 403 changes approximately from curve 401. Therefore, the variable pitch control method can reduce the lag of the given variable pitch speed and improve the variable pitch performance of the wind generating set.

According to the pitch control method of the wind generating set, provided by the embodiment of the disclosure, the given pitch speed is corrected, so that the lag of pitch execution and the lag of the pitch execution on the wind speed change caused by communication data transmission can be made up, the pitch execution of the pitch system is more matched with the actual rotating speed of the wind generating set, and the pitch response speed and the operation stability of the wind generating set are improved.

Fig. 5 is a block diagram illustrating a controller according to an embodiment of the present disclosure.

Referring to fig. 5, a controller 500 according to embodiments of the present disclosure may be implemented as a pitch controller, a main controller, or other dedicated controller of a wind turbine generator set. The controller 500 may include a processor 510 and a memory 520. Processor 510 may include, but is not limited to, a Central Processing Unit (CPU), a Digital Signal Processor (DSP), a microcomputer, a Field Programmable Gate Array (FPGA), a system on a chip (SoC), a microprocessor, an Application Specific Integrated Circuit (ASIC), and the like. Memory 520 may store computer programs to be executed by processor 510. Memory 520 may include high speed random access memory and/or non-volatile computer-readable storage media. The pitch control method of a wind park as described above may be implemented when the processor 510 executes a computer program stored in the memory 520.

Alternatively, the controller 500 may communicate with various other components in the wind park in wired/wireless communication, as well as with other devices in the wind park. Further, the controller 500 may communicate with a device external to the wind farm in a wired/wireless communication manner.

A pitch control method of a wind park according to embodiments of the present disclosure may be written as a computer program and stored on a computer readable storage medium. The computer program, when executed by a processor, may implement a pitch control method of a wind park as described above. 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-RW, DVD + RW, DVD-RAM, BD-ROM, BD-R LTH, BD-RE, blu-ray or optical disk memory, hard Disk Drive (HDD), solid State Disk (SSD), card memory (such as a multimedia card, a Secure Digital (SD) card or an extreme digital (XD) card), magnetic tape, a floppy disk, a magneto-optical data storage device, an optical data storage device, a hard disk, a solid state disk, and any other device configured to store and provide computer programs and any associated data, data files and data structures in a non-transitory manner to a computer processor or computer such that the computer programs and any associated data processors are executed or computer programs. In one example, the computer program and any associated data, data files, and data structures are distributed across networked computer systems such that the computer program and any associated data, data files, and data structures are stored, accessed, and executed in a distributed fashion by one or more processors or computers.

According to the pitch control method and the pitch controller of the wind generating set, provided by the embodiment of the disclosure, the given pitch speed is corrected, so that the lag of pitch execution and the lag of the pitch execution on the wind speed change caused by communication data transmission can be made up, the pitch execution of a pitch system is more matched with the actual rotating speed of the wind generating set, and the pitch response speed and the operation stability of the wind generating set are improved.

Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.

Claims (10)

1. A variable pitch control method of a wind generating set is characterized by comprising the following steps:

responding to the condition that the wind generating set is in a variable pitch state, and determining whether the variable pitch direction at the current control moment is consistent with the variable pitch direction at the previous control moment;

in response to the fact that the pitch variation direction at the current control moment is consistent with the pitch variation direction at the previous control moment, correcting the given pitch variation speed at the current control moment based on the given pitch variation speed at the current control moment, the given pitch variation speed at the previous control moment and a preset correction coefficient;

and controlling a variable pitch motor to perform variable pitch operation based on the corrected given variable pitch speed.

2. The pitch control method of claim 1, further comprising:

and controlling a variable pitch motor to perform variable pitch operation based on the given variable pitch speed at the current control moment in response to the fact that the variable pitch direction at the current control moment is not consistent with the variable pitch direction at the previous control moment.

3. The pitch control method according to claim 1, wherein in response to a given pitch speed at a current control time being both positive and negative with a given pitch speed at a previous control time, it is determined that the pitch direction at the current control time coincides with the pitch direction at the previous control time.

4. The pitch control method according to claim 1, wherein the step of correcting the given pitch speed at the current control time based on the given pitch speed at the current control time, the given pitch speed at the last control time, and a preset correction coefficient comprises:

calculating the difference between the given variable pitch speed at the current control moment and the given variable pitch speed at the last control moment;

determining whether the difference value is smaller than a preset threshold value;

and in response to the difference value being smaller than a preset threshold value, correcting the given variable pitch speed at the current control moment based on the given variable pitch speed at the current control moment, the difference value and a preset correction coefficient.

5. The pitch control method according to claim 4, wherein the step of modifying the given pitch speed at the current control time based on the given pitch speed at the current control time, the difference value and a preset correction factor comprises:

calculating the product of the difference value and a preset correction coefficient;

determining the sum of the given pitch speed at the current control moment and the product as the corrected given pitch speed.

6. The pitch control method according to any of claims 1-5, wherein the predetermined correction factor is an integer greater than 1.

7. The pitch control method according to any one of claims 1-5, wherein the current control time is from the Nth time to the Nth + M time during the pitch operation, where N is an integer greater than 1 and M is an integer greater than or equal to 1.

8. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out a pitch control method according to any one of claims 1 to 7.

9. A pitch controller, characterized in that the pitch controller comprises:

a processor; and

a memory storing a computer program which, when executed by the processor, implements a pitch control method according to any of claims 1 to 7.

10. A wind park according to claim 9, wherein the wind park comprises a pitch controller.

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