A wind turbine propeller retraction method based on wind force changes

Abstract

This invention provides a wind turbine blade retraction method based on wind force variations, belonging to the field of wind turbine blade retraction control technology. Its purpose is to achieve more efficient blade retraction for different blades while maintaining equipment balance and mechanical performance. The method includes: acquiring the blade pitch angle of each blade; obtaining the difference between the minimum blade pitch angle γ and the other two blade pitch angles α and β, respectively, as a first difference ε1 and a second difference ε2, where the first difference ε1 is not less than the second difference ε2; assigning an initial blade retraction speed to each blade based on the relationship between the first difference ε1, the second difference ε2, and a difference threshold δ, and then performing blade retraction; during the retraction process, adaptively adjusting the blade retraction speed based on the initial blade retraction speed according to wind conditions. This invention has the advantages of high blade retraction efficiency while maintaining equipment balance and reducing equipment wear.

Description

Technical Field

[0001] This invention relates to the field of wind turbine propeller retraction control technology, and more specifically, to a wind turbine propeller retraction method based on wind force changes. Background Technology

[0002] With the development of new energy sources, green energy, especially wind power, is playing an increasingly important role in the energy supply sector. During wind power generation, pitch control is required to adapt to changes in environmental wind conditions, thereby altering the angle of the wind turbine blades to ensure better power generation with minimal equipment wear and tear.

[0003] When a malfunction or environmental anomaly occurs, a shutdown is necessary, often requiring pitch control. The pitch control process adjusts the pitch speed based on wind conditions. Currently, wind turbine blades typically employ independent pitch control, meaning each blade has its own control system that adjusts pitch according to real-time conditions. This can lead to significant differences in the operating states (e.g., angles) of different blades during operation. Furthermore, if pitch control relies solely on wind speed changes without considering the conditions of other blades, it can cause equipment imbalance. Over time, this accelerates equipment aging and reduces its lifespan.

[0004] Therefore, it is necessary to optimize the propeller retraction control, taking into account the differences in the operating conditions of different blades and the wind conditions. Based on this, more efficient propeller retraction can be performed on different blades, while also taking into account the balance and mechanical performance of the equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a wind turbine blade retraction method based on wind force changes, which aims to retract the blades of different blades more efficiently, while taking into account the balance and mechanical performance of the equipment.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] A wind turbine propeller retraction method based on wind force changes includes the following steps:

[0008] The blade pitch angle of each blade was collected and sorted from largest to smallest as α, β, and γ.

[0009] Obtain the difference between the minimum blade pitch angle γ and the other two blade pitch angles α and β, which are the first difference ε1 and the second difference ε2, respectively. The first difference ε1 is not less than the second difference ε2.

[0010] Based on the relationship between the first difference ε1, the second difference ε2, and the difference threshold δ, each blade is assigned an initial retraction velocity and the retraction is performed.

[0011] During the paddle retraction process, the paddle retraction speed is adaptively adjusted based on the wind conditions and the initial paddle retraction speed of each blade.

[0012] Preferably, the step of assigning an initial blade recovery speed to each blade and performing blade recovery includes:

[0013] The three blades with blade pitch angles of α, β, and γ are called Blade_max, Blade_mid, and Blade_min, respectively.

[0014] If both the first difference ε1 and the second difference ε2 are greater than the difference threshold δ, then Blade_max and Blade_mid will first be at their respective initial paddle recovery speeds V. Blade_max and V Blade_mid After time Δt1, Blade_min begins to retract the propellers at its initial retracting speed V. Blade_min When retracting the oars, at this time:

[0015] V Blade_max =V1;

[0016] V Blade_mid =V1*ε2 / ε1;

[0017]

[0018]

[0019] If only the first difference ε1 is greater than the difference threshold δ, Blade_max first uses its initial paddle retraction speed V. Blade_max After time Δt1, Blade_mid and Blade_min begin retracting the paddles at their respective initial retracting velocities.

[0020] V Blade_max =V1;

[0021]

[0022]

[0023]

[0024] If the first difference ε1 and the second difference ε2 are not greater than the difference threshold δ, each blade simultaneously begins to retract its blade at the initial retraction speed V1.

[0025] Preferably, V1 is determined based on the current wind force and the mechanical properties of the wind turbine itself.

[0026] The greater the wind force, the larger V1 becomes, and V1 is less than the threshold propeller speed V that the wind turbine's mechanical properties can withstand. th .

[0027] Preferably, the value of V1 ranges from 4 to 7 degrees per second.

[0028] Preferably, the method for adaptively adjusting the paddle recovery speed includes:

[0029] A vibration sensor is installed on each blade to detect its vibration amplitude.

[0030] If the vibration amplitude A of a certain blade exceeds the vibration safety threshold A th Then, based on the vibration amplitude A of the blade, the blade's retraction speed is accelerated, and the accelerated retraction speed V new .

[0031] Preferably, the method for accelerating the blade's retraction speed based on the blade's vibration amplitude A is as follows:

[0032] Obtain the evaluation parameter p:

[0033]

[0034] If the evaluation parameter p > 50%

[0035] V new =V th ;

[0036] Among them, V new To calculate the accelerated retraction speed of the blade, V th The threshold blade speed that the wind turbine's own mechanical properties can withstand;

[0037] If the evaluation parameter p ≤ 50%:

[0038] V new =V old *p*(V th -V old );

[0039] Among them, V old The retraction speed of the blade before acceleration is applied is equal to the initial retraction speed of the blade.

[0040] Preferably, if the vibration amplitude A of two blades exceeds the vibration safety threshold a th And the evaluation parameters p for the two blades are p1 and p2, respectively;

[0041] After accelerating the retraction speed of the two blades, accelerate the remaining blade:

[0042] V new =V old *min(p1,p2)*(V th -V old );

[0043] If V new >V th V new =V th .

[0044] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0045] This invention provides targeted control for each blade, making it more adaptable;

[0046] This invention adjusts and coordinates the blade retraction completion time as much as possible, which is beneficial to the balance of the entire wind turbine equipment. Furthermore, it can reduce equipment wear and extend equipment service life.

[0047] The basic speed of this invention depends on wind force and the performance of the equipment itself, ensuring that the paddle is retracted as quickly as possible under adverse conditions, while preventing the equipment from exceeding its capacity.

[0048] This invention monitors the vibration of each blade of the equipment after the initial paddle retraction action, thereby predicting the real-time wind conditions. The measurement is simple and easy to implement.

[0049] After the initial retraction action, this invention will adjust the retraction speed of each blade of the equipment based on the wind force, further ensuring the retraction efficiency and preventing the situation where the wind force is too great but the machine cannot be stopped in time.

[0050] This invention has a reasonable design, a simple algorithm, and low computational cost. It can balance the efficiency of paddle collection and the wear and tear on equipment, making it easy to promote and apply. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic flowchart of a wind turbine propeller retraction method based on wind force changes, provided as an embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0054] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0055] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0056] Example 1

[0057] See Figure 1 This embodiment provides a wind turbine paddle retraction method based on wind force changes, including the following steps:

[0058] Step S1: Collect the blade pitch angle of each blade and sort them in descending order as α, β and γ;

[0059] Step S2: Obtain the difference between the minimum blade pitch angle γ and the other two blade pitch angles α and β, which are the first difference ε1 and the second difference ε2, respectively. The first difference ε1 is not less than the second difference ε2.

[0060] Step S3: Based on the relationship between the first difference ε1, the second difference ε2 and the difference threshold δ, assign an initial blade recovery speed to each blade and perform blade recovery;

[0061] Step S4: During the paddle retraction process, the paddle retraction speed is adaptively adjusted based on the wind conditions and the initial paddle retraction speed of each blade.

[0062] The basic idea of ​​this embodiment is as follows:

[0063] During the shutdown process, wind turbines require blade retraction. Since modern wind turbines typically use independent pitch control, the blade pitch angle of each blade may differ. Therefore, significant angle differences can exist. If the blades are retracted at the same speed, the retraction time for each blade may vary considerably. This results in significantly different wind pressures on each blade, causing unbalanced damage to the turbine. Over time, this accumulated damage can severely impact the lifespan of the wind turbine equipment.

[0064] Therefore, this embodiment considers the differences in blade pitch angle between each blade and sets separate blade retraction speeds for them. The aim is to ensure that all blades retract simultaneously as much as possible. Furthermore, the wind conditions experienced by each blade are continuously monitored during the retraction process, and the retraction speed is adaptively adjusted to ensure more efficient blade retraction even when excessive wind conditions occur.

[0065] The V1 value can be an empirical value. Operators can set up a system for V1 to follow wind speed changes based on the wind turbine's parameters. At the start of each propeller retraction operation, the system determines the V1 value for that operation based on this system and the current wind speed. Alternatively, operators can input a suitable V1 value at the start of each retraction operation, based on real-time conditions.

[0066] Example 2

[0067] This embodiment is based on the technical solution of embodiment 1, and further explains the setting of the initial blade retraction speed in step S3.

[0068] In this embodiment, the step of assigning an initial blade recovery speed to each blade and performing blade recovery includes:

[0069] The three blades with blade pitch angles of α, β, and γ are called Blade_max, Blade_mid, and Blade_min, respectively.

[0070] If both the first difference ε1 and the second difference ε2 are greater than the difference threshold δ, then Blade_max and Blade_mid will first be at their respective initial paddle recovery speeds V. Blade_max and V Blade_mid After time Δt1, Blade_min begins to retract the propellers at its initial retracting speed V. Blade_min When retracting the oars, at this time:

[0071] V Blade_max =V1;

[0072] V Blade_mid =V1*ε2 / ε1;

[0073]

[0074]

[0075] If only the first difference ε1 is greater than the difference threshold δ, Blade_max first uses its initial paddle retraction speed V. Blade_max After time Δt1, Blade_mid and Blade_min begin retracting the paddles at their respective initial retracting velocities.

[0076] V Blade_max =V1;

[0077]

[0078]

[0079]

[0080] If the first difference ε1 and the second difference ε2 are not greater than the difference threshold δ, each blade simultaneously begins to retract its blade at the initial retraction speed V1.

[0081] Furthermore, V1 is determined based on the current wind force and the mechanical properties of the wind turbine itself.

[0082] The greater the wind force, the larger V1 becomes, and V1 is less than the threshold propeller speed V that the wind turbine's mechanical properties can withstand. th .

[0083] In this embodiment, the value of V1 ranges from 4 to 7 degrees per second.

[0084] The core idea of ​​this embodiment is:

[0085] During the retraction process, we should try to ensure that all blades retract simultaneously.

[0086] When the angle difference between the blades is small, that is, when the angle difference between any two blades does not exceed the difference threshold δ, all blades can be controlled to retract at the same speed. In this case, the time difference for each blade to complete the retraction will naturally be within the expected time threshold.

[0087] However, if the angle difference between the blades is too large, the retraction speed of each blade needs to be adjusted separately so that they can retract as simultaneously as possible.

[0088] Here, if we adjust based on the blade with the smallest pitch angle, other blades with pitch angles significantly different from the blade with the smallest pitch angle will retract their propellers first. Only after a certain period of time will the blade with the smallest pitch angle begin to retract its propellers. Specifically, the blade with the smallest pitch angle will only begin to retract its propellers when the difference in pitch angle between it and the blade with the smallest pitch angle begins to reach the difference threshold δ during the retraction process.

[0089] The initial retraction speed of each blade is proportionally adjusted based on the initial retraction speed of the blade with the largest pitch angle. Under this initial retraction speed setting, all blades can basically complete the retraction simultaneously.

[0090] Example 3

[0091] This embodiment further explains the method for adaptively adjusting the paddle speed in step S4, based on the technical solution of implementation 1.

[0092] As a preferred embodiment, the method for adaptively adjusting the paddle recovery speed includes:

[0093] A vibration sensor is installed on each blade to detect its vibration amplitude.

[0094] If the vibration amplitude A of a certain blade exceeds the vibration safety threshold A th Then, based on the vibration amplitude A of the blade, the blade's retraction speed is accelerated, and the accelerated retraction speed V new .

[0095] The method for accelerating the blade's retraction speed based on the blade's vibration amplitude A is as follows:

[0096] Obtain the evaluation parameter p:

[0097]

[0098] If the evaluation parameter p > 50%

[0099] V new =V th ;

[0100] Among them, V new To calculate the accelerated retraction speed of the blade, V th The threshold blade speed that the wind turbine's own mechanical properties can withstand;

[0101] If the evaluation parameter p ≤ 50%:

[0102] V new =V old *p*(V th-V old );

[0103] Among them, V old The retraction speed of the blade before acceleration is applied is equal to the initial retraction speed of the blade.

[0104] Furthermore, if the vibration amplitude A of two blades exceeds the vibration safety threshold A... th And the evaluation parameters p for the two blades are p1 and p2, respectively;

[0105] After accelerating the retraction speed of the two blades, accelerate the remaining blade:

[0106] V new =V old *min(p1,p2)*(V th -V old );

[0107] If V new >V th V new =V th .

[0108] Since not only wind speed but also wind direction affects the propeller retraction, the blade angle is adjusted to adapt to both wind force and wind direction during the retraction process. Therefore, the wind pressure on the blades may change due to the change in the retraction angle, which may even reach a level that is harmful to the wind turbine. In this case, the retraction needs to be completed more quickly.

[0109] Therefore, after setting the initial propeller retraction speed, we need to make a secondary adjustment to the retraction speed during the retraction process. However, the wind direction is difficult to monitor, so we install a vibration sensor on the front of each blade to monitor the vibration changes during the blade turning process, thereby sensing the actual wind pressure that the blade is subjected to.

[0110] We use evaluation parameters as a standard to determine the degree of excessive vibration of the wind turbine blades. If the vibration exceeds the standard by too much, we directly increase the propeller speed to the maximum.

[0111] It's important to note that when the retraction speed of two blades is accelerated, it indicates that most of the turbine blades are under high wind pressure. Therefore, the remaining blades are also accelerated to ensure the entire system completes retraction and shutdown as soon as possible. Here, the remaining blades are assigned the same acceleration factor as the smaller of the other two blades. If the initial retraction speed of the remaining blades multiplied by this acceleration factor exceeds the threshold retraction speed V... th For the safety of the wind turbine equipment itself, the acceleration is only up to V. th.

[0112] It should be noted that excessively fast propeller retraction speed can also have adverse effects, such as increasing the structural load on the wind turbine and causing mechanical vibration. Therefore, the adjustment process requires consideration from multiple aspects. Thus, this embodiment uses V... th As an adjustment limit. V th The parameters can be determined based on the actual mechanical data of each wind turbine, for example, by referring to its manual parameters.

[0113] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for wind turbine propeller retraction based on wind force changes, characterized in that, Includes the following steps: The blade pitch angle of each blade was collected and sorted from largest to smallest as α, β, and γ. Obtain the difference between the minimum blade pitch angle γ and the other two blade pitch angles α and β, which are the first difference ε1 and the second difference ε2, respectively. The first difference ε1 is not less than the second difference ε2. Based on the relationship between the first difference ε1, the second difference ε2, and the difference threshold δ, each blade is assigned an initial retraction velocity and the retraction is performed. During the paddle retraction process, the paddle retraction speed is adaptively adjusted based on the wind conditions and the initial paddle retraction speed of each blade. The process of assigning an initial retraction velocity to each blade and performing retraction includes: The three blades with blade pitch angles of α, β, and γ are called Blade_max, Blade_mid, and Blade_min, respectively. If both the first difference ε1 and the second difference ε2 are greater than the difference threshold δ, then Blade_max and Blade_mid will first be at their respective initial paddle recovery speeds V. Blade_max and V Blade_mid After time Δt1, Blade_min begins to retract the propellers at its initial retracting speed V. Blade_min When retracting the oars, at this time: V Blade_max =V1; V Blade_mid =V1*ε2 / ε1; If only the first difference ε1 is greater than the difference threshold δ, Blade_max first uses its initial paddle retraction speed V. Blade_max After time Δt1, Blade_mid and Blade_min begin retracting the paddles at their respective initial retracting velocities. V Blade_max =V1; If the first difference ε1 and the second difference ε2 are not greater than the difference threshold δ, each blade simultaneously begins to retract its blade at the initial retraction speed V1.

2. The wind turbine propeller retraction method based on wind force variation according to claim 1, characterized in that: The method for determining V1 is based on the current wind force value and the mechanical properties of the wind turbine itself; The greater the wind force, the larger V1 becomes, and V1 is less than the threshold propeller speed V that the wind turbine's mechanical properties can withstand. th .

3. The wind turbine propeller retraction method based on wind force variation according to claim 2, characterized in that: The value of V1 ranges from 4 to 7 degrees per second.

4. The wind turbine propeller retraction method based on wind force variation according to claim 1, characterized in that, The method for adaptively adjusting the paddle recovery speed includes: A vibration sensor is installed on each blade to detect its vibration amplitude. If the vibration amplitude A of a certain blade exceeds the vibration safety threshold A th Then, based on the vibration amplitude A of the blade, the blade's retraction speed is accelerated, and the accelerated retraction speed V new .

5. A wind turbine propeller retraction method based on wind force variation according to claim 4, characterized in that, The method to accelerate the blade's retraction speed based on the blade's vibration amplitude A is as follows: Obtain the evaluation parameter p: If the evaluation parameter p > 50%: V new =V th ; Among them, V new To calculate the accelerated retraction speed of the blade, V th The threshold blade speed that the wind turbine's own mechanical properties can withstand; If the evaluation parameter p ≤ 50%: V new =V old *p*(V th -V old ); Among them, V old The retraction speed of the blade before acceleration is applied is equal to the initial retraction speed of the blade.

6. A wind turbine propeller retraction method based on wind force changes according to claim 5, characterized in that, If the vibration amplitude A of two blades exceeds the vibration safety threshold A th And the evaluation parameters p for the two blades are p1 and p2, respectively; After accelerating the retraction speed of the two blades, accelerate the remaining blade: In new =V old *min(p1,p2)*(V th -V old ); If V new >V th V new =V th .

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