A control method and system for dynamic advance variable pitch of a large megawatt wind turbine generator set

Abstract

The application discloses a control method and system for dynamic advance variable pitch of a large-megawatt wind turbine generator set, and the method comprises the following steps: S1, obtaining wind speed, wind wheel speed, generator power and current pitch angle Pitch of the wind turbine generator set during operation; S2, calculating current tip speed ratio Lambda of the wind turbine generator set based on the wind speed and the wind wheel speed; calculating current power coefficient Cp based on the wind speed, the generator power and air density * ; S3, obtaining ideal steady-state pitch angle Pitch* based on the tip speed ratio Lambda and the power coefficient Cp * ; S4, calculating deviation E between the current pitch angle Pitch and the ideal steady-state pitch angle Pitch*, and adjusting the advance variable pitch value according to the deviation E; wherein the larger the deviation E is, the larger the advance variable pitch value is. The application has the advantages of improving power generation of the unit, improving safety of the unit and low cost.

Description

Technical Field

[0001] This invention mainly relates to the field of wind power generation technology, specifically to a control method and system for dynamic advance pitch control of a large-megawatt wind turbine generator set. Background Technology

[0002] As the capacity of wind turbine generators increases, their rotor diameter and blade length become larger. The use of long, flexible blades necessitates designing larger advance pitch values ​​to reduce the ultimate load on the blades and hub, thus avoiding blade swirl. However, excessively large advance pitch values ​​can result in significant power loss. Therefore, how to increase the generator's power output while ensuring the ultimate load on the blades and hub and avoiding blade swirl will be a major challenge in the design of the overall control system.

[0003] The design of advance pitch values ​​for wind turbine generators is closely related to the ultimate load of the blades and hub, as well as the blade clearance protection. Therefore, the following schemes are currently mainly adopted for the design of advance pitch values ​​for large-megawatt wind turbine generators:

[0004] (1) By designing a larger advance pitch value, the ultimate load on the blades and hub during the operation of the whole machine can be reduced, and the blade clearance can be ensured. Although this method can have a positive impact on the ultimate load and blade clearance to a certain extent, it will sacrifice a lot of power generation, and different models and blades need to be adjusted according to the actual situation, so it is not very universal;

[0005] (2) Reduce the advance pitch angle by adding a clearance radar while ensuring blade clearance. Although this solution can increase the unit's power generation while ensuring blade clearance, it requires the installation of additional hardware equipment, which will increase the overall cost of the unit. Summary of the Invention

[0006] To address the technical problems existing in the prior art, this invention provides a control method and system for dynamic advance pitch control of a large-megawatt wind turbine generator set to increase the generator's power generation while ensuring ultimate load and blade clearance.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0008] A control method for dynamic advance pitch control of a large-megawatt wind turbine generator set includes the following steps:

[0009] S1. Obtain the wind speed v, wind turbine speed ω, generator power P, and the current pitch angle Pitch of the wind turbine generator set during operation.

[0010] S2. Based on wind speed v and rotor speed ω, the current tip speed ratio Lambda of the computer group;

[0011] Calculate the current power factor Cp based on wind speed v, generator power P, and air density ρ. * ;

[0012] S3, based on the tip speed ratio Lambda and the power coefficient Cp * This yields the ideal steady-state pitch angle.

[0013] S4. The deviation E between the current pitch angle of the computer group and the ideal steady-state pitch angle*, and adjust the advance pitch value according to the deviation E; where the larger the deviation E, the larger the advance pitch value.

[0014] Preferably, in step S4, the specific process of adjusting the advance pitch value according to the deviation E is as follows:

[0015] The deviation E is compared with the preset first threshold P1 and second threshold P2, where P1>P2; if the deviation E is greater than P1, the current advance pitch value is switched from the initial value BPS to PS=BPS×k, k≥1; if the deviation E is less than P2, the advance pitch value is restored to the initial value BPS; the initial value of the advance pitch value is preset according to the total power of the engine.

[0016] Preferably, the value of k ranges from 1 to 3.

[0017] Preferably, the value range of P1 is 4 to 6 degrees, and the value range of P2 is 3 to 4 degrees.

[0018] Preferably, the formula for the current tip speed ratio Lambda of the computer group in step S2 is:

[0019]

[0020] Where R is the radius of the wind turbine.

[0021] Preferably, in step S2, the current power coefficient Cp is calculated. * The formula is:

[0022]

[0023] Where A is the area of ​​the wind turbine.

[0024] Preferably, the formula for calculating the deviation E in step S4 is:

[0025] E = |Pitch - Pitch* |.

[0026] Preferably, in step S3, the tip speed ratio Lambda and the power coefficient Cp are used to determine the optimal parameters. *The ideal steady-state pitch angle Pitch* is obtained by querying the inherent Cp-Lambda-Pitch three-dimensional table of the unit; the Cp-Lambda-Pitch three-dimensional table is used to map the ideal pitch angle under different operating conditions.

[0027] Preferably, in step S1, the acquired wind speed v, wind turbine speed ω, generator power P, and the current pitch angle of the unit are cleaned and filtered to eliminate signal interference.

[0028] The present invention also discloses a control system for dynamic advance pitch control of a large megawatt wind turbine generator set, including a memory and a processor connected to each other. The memory stores a computer program, which executes the steps of the method described above when the processor runs the computer program.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] This invention employs a smaller advance pitch value (BPS) when the unit is operating smoothly (i.e., when the deviation E is less than P2). A smaller pitch angle means the wind turbine has better aerodynamic efficiency, capturing more wind energy and directly improving the power coefficient, thus increasing power output. This invention only dynamically switches to a larger advance pitch value (PS) to cope with transient adverse operating conditions when load or clearance risks are detected (i.e., when the deviation E is greater than P1). Compared to traditional fixed large advance pitch values, this invention ensures the unit operates in a more efficient aerodynamic range for most of its normal operating time, avoiding unnecessary power generation losses.

[0031] This invention calculates the ideal steady-state pitch angle * in real time and compares it with the current pitch angle of the turbine. This allows it to keenly detect trends of abnormally increasing loads or exacerbated tip deflection (which may lead to insufficient clearance). When external wind conditions change abruptly (such as gusts or wind shear), the actual pitch angle adjusts rapidly, causing a sudden increase in the deviation E from the ideal steady-state pitch angle *. Once the deviation exceeds the safety threshold (P1), the system responds in milliseconds, immediately increasing the advance pitch value to provide stronger load suppression and blade straightening effects. This ensures that the blade root bending moment and hub load do not exceed limits and guarantees sufficient tip-to-tower clearance. Compared to solutions that rely entirely on clearance radar, this invention employs a hybrid feedforward and feedback control strategy. It not only reacts when physically approaching danger but also proactively intervenes in the early stages when the load is about to exceed limits, offering higher safety and greater foresight.

[0032] The entire control scheme of this invention is based entirely on the existing standard sensors (such as anemometers, encoders, and power sensors) and main controller of the unit. It can be deployed by upgrading the algorithm without the need to install expensive additional equipment (such as lidar and air clearance radar), thus saving the cost of hardware procurement, installation, and maintenance.

[0033] The core parameters of the control logic of this invention (such as thresholds P1 and P2, gain coefficient k, and initial value BPS) can be customized according to the load characteristics, tower clearance requirements, blade stiffness, etc. of different models, which can quickly adapt to units with different rotor diameters and different rated power, greatly enhancing the market promotion value of the technology. Attached Figure Description

[0034] Figure 1 The flowchart shows an embodiment of the control method for dynamic advance pitch control of large-megawatt wind turbine generators according to the present invention.

[0035] Figure 2 This is a flowchart illustrating the method for calculating the ideal steady-state pitch angle Pitch* in this invention.

[0036] Figure 3 This is a flowchart of the method for adjusting the advance pitch value in this invention.

[0037] Figure 4 This is a simulation verification diagram of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] like Figure 1 As shown in the figure, the control method for dynamic advance pitch control of a large-megawatt wind turbine generator provided in this embodiment of the invention includes the following steps:

[0040] S1. During the normal operation of the wind turbine generator set, collect data such as wind speed v, wind turbine speed ω, generator power P, and the current pitch angle of the unit, and perform data cleaning and filtering.

[0041] S2. Based on wind speed v and rotor speed ω, the current tip speed ratio Lambda of the computer group;

[0042] Calculate the current power factor Cp based on wind speed v, generator power P, and air density ρ. * ;

[0043] S3, based on the tip speed ratio Lambda and the power coefficient Cp * Query the inherent Cp-Lambda-Pitch three-dimensional table of the unit to obtain the ideal steady-state pitch angle Pitch*;

[0044] S4. The deviation E between the current pitch angle of the computer group and the ideal steady-state pitch angle* is calculated, and the advance pitch value is adjusted according to the deviation E. The larger the deviation E, the larger the advance pitch value. Specifically, the deviation E between the current pitch angle of the computer group and the ideal steady-state pitch angle* is calculated, and this deviation E is compared with the preset first threshold P1 and second threshold P2, where P1>P2. If the deviation E is greater than P1, the current advance pitch value is switched from the initial value BPS to PS=BPS×k, k≥1. If the deviation E is less than P2, the advance pitch value is restored to the initial value BPS. The initial value of k is 2, which can be adjusted appropriately according to the turbulence magnitude of different plant sites, with a specific value range of 1-3.

[0045] The initial value BPS is a small advance pitch value set at the beginning of the unit's operation, specifically preset based on the overall power output. Of course, in other embodiments, the aforementioned advance pitch value can also be linearly adjusted (e.g., proportionally adjusted) based on the deviation E.

[0046] This invention employs a smaller advance pitch value (BPS) when the unit is operating smoothly (i.e., when the deviation E is less than P2). A smaller pitch angle means the wind turbine has better aerodynamic efficiency, capturing more wind energy and directly improving the power coefficient, thus increasing power output. This invention only dynamically switches to a larger advance pitch value (PS) to cope with transient adverse operating conditions when load or clearance risks are detected (i.e., when the deviation E is greater than P1). Compared to traditional fixed large advance pitch values, this invention ensures the unit operates in a more efficient aerodynamic range for most of its normal operating time, avoiding unnecessary power generation losses.

[0047] This invention calculates the ideal steady-state pitch angle * in real time and compares it with the current pitch angle of the turbine. This allows it to keenly detect trends of abnormally increasing loads or exacerbated tip deflection (which may lead to insufficient clearance). When external wind conditions change abruptly (such as gusts or wind shear), the actual pitch angle adjusts rapidly, causing a sudden increase in the deviation E from the ideal steady-state pitch angle *. Once the deviation exceeds the safety threshold (P1), the system responds in milliseconds, immediately increasing the advance pitch value to provide stronger load suppression and blade straightening effects. This ensures that the blade root bending moment and hub load do not exceed limits and guarantees sufficient tip-to-tower clearance. Compared to solutions that rely entirely on clearance radar, this invention employs a hybrid feedforward and feedback control strategy. It not only reacts when physically approaching danger but also proactively intervenes in the early stages when the load is about to exceed limits, offering higher safety and greater foresight.

[0048] The entire control scheme of this invention is based entirely on the existing standard sensors (such as anemometers, encoders, and power sensors) and main controller of the unit. It can be deployed by upgrading the algorithm without the need to install expensive additional equipment (such as lidar and air clearance radar), thus saving the cost of hardware procurement, installation, and maintenance.

[0049] The core parameters of the control logic of this invention (such as threshold P1, P2, gain coefficient k, and initial value BPS) can be customized according to the load characteristics, tower clearance requirements, blade stiffness, etc. of different models, which can quickly adapt to units with different rotor diameters and different rated power, greatly enhancing the market promotion value of the technology.

[0050] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0051] like Figures 1-2 As shown, the control method for dynamic advance pitch control of a large-megawatt wind turbine generator set according to an embodiment of the present invention includes the following steps:

[0052] S1. During the normal operation of the wind turbine generator set, collect wind speed, wind turbine speed and generator power, and perform data cleaning and filtering to ensure data reliability and eliminate signal interference;

[0053] S2. Based on the filtered wind speed and generator speed, calculate the current tip speed ratio Lambda of the unit. The specific calculation formula is as follows:

[0054]

[0055] Where ω is the wind turbine rotation speed, R is the wind turbine radius, and v is the wind speed;

[0056] The current power coefficient Cp is calculated based on the current filtered wind speed, rotor diameter, and air density. * The specific calculations are as follows:

[0057]

[0058] Where P is the generator power; ρ is the air density; and A is the wind turbine area, which is calculated based on the wind turbine diameter.

[0059] S3. Based on the current tip speed ratio Lambda and power coefficient Cp of the unit * By consulting the inherent Cp-Lambda-Pitch three-dimensional table of the generator set, the ideal steady-state pitch angle Pitch* can be obtained.

[0060] Table 1. Cp-Lambda-Pitch 3D Table

[0061]

[0062] S4. Obtain the current pitch angle of the unit and perform filtering processing to obtain the current actual pitch angle Pitch;

[0063] Compare the current actual pitch angle Pitch with the ideal steady-state pitch angle Pitch*, and calculate the deviation E between the current actual pitch angle Pitch and the ideal steady-state pitch angle Pitch*;

[0064] E = ∣Pitch - Pitch*∣

[0065] Set the control first threshold P1 and the second threshold P2, where P1 > P2; the value range of P1 is 4 - 6deg, and the value range of P2 is 3 - 4deg. P2 < P1 is the dead zone and can be appropriately adjusted according to the turbulence size of different plant sites.

[0066] And set a smaller early pitch change value BPS (initial value) at the beginning of the unit operation, and adjust it appropriately according to the size of the overall machine power; specifically, it is obtained by querying the overall machine power - early pitch change value table according to the overall machine power, where the overall machine power - early pitch change value table is shown in Table 2:

[0067] Table 2 Overall machine power - early pitch change value table

[0068]

[0069] If the deviation E between the current actual pitch angle Pitch and the ideal steady-state pitch angle Pitch* is greater than the threshold P1, immediately double the current early pitch change from BPS to PS = BPS * 2. When the deviation E is less than the threshold P2, the early pitch change is restored to BPS, as Figure 3 shown.

[0070] Simulation verification: Use a 10MW unit (WT10000D230H125) for simulation verification. As Figure 4 shown, the default initial value of the early pitch change value BPS is 5deg. When P1 is set to 4deg, after about 141s, the deviation E between the ideal pitch angle Pitch* and the actual pitch angle Pitch is greater than P1, and the early pitch change value is increased from 5deg to PS = 5 × 2 = 10deg to verify the stability of the logic effect.

[0071] The embodiment of the present invention also provides a control system for dynamic early pitch change of a large MW wind turbine generator, including a memory and a processor connected to each other. A computer program is stored on the memory, and when the computer program is run by the processor, it executes the steps of the above method. The control system of the present invention, corresponding to the above control method, also has the advantages of the above control method.

[0072] The present invention can implement all or part of the processes in the methods of the above embodiments, or it can be implemented by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium includes: any entity or device capable of carrying computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. The memory is used to store computer programs and / or modules. The processor implements various functions by running or executing the computer programs and / or modules stored in the memory, and by calling data stored in the memory. The memory may include high-speed random access memory, as well as non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0073] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A control method for dynamic advance pitch control of a large-megawatt wind turbine generator set, characterized in that, Including the following steps: S1. Obtain the wind speed v, wind turbine speed ω, generator power P, and the current pitch angle Pitch of the wind turbine generator set during operation. S2. Based on wind speed v and rotor speed ω, the current tip speed ratio Lambda of the computer group; Calculate the current power factor Cp based on wind speed v, generator power P, and air density ρ. * ; S3, based on the tip speed ratio Lambda and the power coefficient Cp * This yields the ideal steady-state pitch angle. S4. The deviation E between the current pitch angle of the computer group and the ideal steady-state pitch angle*, and adjust the advance pitch value according to the deviation E; where the larger the deviation E, the larger the advance pitch value. In step S4, the specific process of adjusting the advance pitch value according to the deviation E is as follows: The deviation E is compared with the preset first threshold P1 and second threshold P2, where P1>P2; if the deviation E is greater than P1, the current advance pitch value is switched from the initial value BPS to PS=BPS×k, k≥1; if the deviation E is less than P2, the advance pitch value is restored to the initial value BPS; where the initial value BPS is preset according to the total power of the engine. In step S3, based on the tip speed ratio Lambda and the power coefficient Cp * The ideal steady-state pitch angle Pitch* is obtained by querying the inherent Cp-Lambda-Pitch three-dimensional table of the unit; the Cp-Lambda-Pitch three-dimensional table is used to map the ideal pitch angle under different operating conditions.

2. The control method for dynamic advance pitch control of a large-megawatt wind turbine generator set according to claim 1, characterized in that, The value of k ranges from 1 to 3.

3. The control method for dynamic advance pitch control of a large-megawatt wind turbine generator set according to claim 1 or 2, characterized in that, The value range of P1 is 4 to 6 degrees, and the value range of P2 is 3 to 4 degrees.

4. The control method for dynamic advance pitch control of a large-megawatt wind turbine generator set according to claim 1 or 2, characterized in that, The formula for the current tip speed ratio Lambda of the computer group in step S2 is: Where R is the radius of the wind turbine.

5. The control method for dynamic advance pitch control of a large-megawatt wind turbine generator set according to claim 1 or 2, characterized in that, In step S2, the current power factor Cp is calculated. * The formula is: Where A is the area of ​​the wind turbine.

6. The control method for dynamic advance pitch control of a large-megawatt wind turbine generator set according to claim 1 or 2, characterized in that, The formula for calculating the deviation E in step S4 is: E = |Pitch - Pitch* |.

7. The control method for dynamic advance pitch control of a large-megawatt wind turbine generator set according to claim 1 or 2, characterized in that, In step S1, the acquired wind speed v, wind turbine speed ω, generator power P, and the current pitch angle of the unit are cleaned and filtered to eliminate signal interference.

8. A control system for dynamic advance pitch control of a large-megawatt wind turbine generator set, comprising a memory and a processor interconnected, wherein the memory stores a computer program, characterized in that, The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1-7.

Images