A yaw control method for wind turbines with high efficiency and wind capture

Abstract

The present invention discloses a yaw control method for efficiently capturing wind in a wind turbine. The wind turbine is a horizontal-axis wind turbine equipped with a laser radar anemometer at the front of its nacelle and a mechanical wind vane at the rear. The yaw control method yaws the wind turbine in a sequence of first detecting the normal state of the wind measuring equipment and then detecting the faulty state of the wind measuring equipment. This method enables the wind turbine to efficiently capture wind, reduce unnecessary power loss, and maintain safe operation during service, resulting in significant economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a yaw control method for a wind turbine generator capable of efficiently catching wind. Background Art

[0002] For a long time, wind turbines have captured wind energy by performing yaw maneuvers based on the wind direction measured by a mechanical wind vane mounted at the rear of the nacelle. However, the mechanical wind vane at the rear of the nacelle can only measure wind direction at its installation location—i.e., at the rear of the nacelle—and cannot measure the original wind direction at the front of the rotor. The measured wind direction at the rear of the nacelle is interfered with by the rotation of the rotor at the front of the nacelle. This is particularly pronounced in large-capacity wind turbines with large swept areas. In other words, there is a significant deviation between the wind direction information measured by the mechanical wind vane and the original wind direction information at the front of the nacelle. Since wind turbines utilize wind energy through the rotor at the front of the nacelle, the wind direction information measured by the mechanical wind vane at the rear of the nacelle exhibits hysteresis and interference, making it impossible to accurately and reliably guide yaw maneuvers. Consequently, wind energy cannot be efficiently utilized, resulting in unnecessary power loss.

[0003] To measure wind direction as accurately as possible, the applicant previously disclosed a technology for measuring wind direction using a laser wind radar and a nacelle-top wind vane. For details, see the Chinese patent document titled "A Method for Controlling Gust-Reduced Load Operation of a Wind Turbine" (Publication No. CN 114876730 A, published on August 9, 2022). This technology uses a laser wind radar to collect wind speed and direction data at a set distance from the wind turbine rotor. The wind speed data is used to determine the wind speed at the wind turbine. The wind direction is determined using the nacelle-top wind vane. If the deviation between the wind direction measured by the laser wind radar and the wind direction measured by the nacelle-top wind vane is within a set degree, the wind direction is yawed based on the laser radar's wind direction. Otherwise, the wind direction measured by the nacelle-top wind vane is used as the reference, ensuring that the wind turbine is accurately facing the wind. The technical means of measuring wind direction information disclosed by this technology effectively improves the technical problems existing in the above-mentioned measurement of wind direction information by relying solely on mechanical wind vanes, and is conducive to accurately and reliably guiding wind turbines to perform efficient wind-catching yaw movements.

[0004] However, the wind-capturing technologies of the above-mentioned wind turbines are all based on the normal operation of the wind measuring equipment. Once the wind measuring equipment fails and cannot obtain wind direction information, the wind turbine is in a "blind" state waiting for maintenance, unable to capture wind and perform yaw-to-wind actions, temporarily interrupting the power generation efficiency, and at the same time unable to keep the wind turbine running safely.

[0005] Currently, wind turbines are developing towards intelligentization. Ensuring stable and safe operation, improving wind capture efficiency, and reducing power losses during service are crucial for generating significant benefits. Therefore, it is essential to improve intelligent yaw control technology for wind turbines. Summary of the Invention

[0006] The technical purpose of the present invention is to provide a wind turbine yaw control method that can enable the wind turbine to efficiently capture wind and reduce unnecessary power loss during service, in view of the particularity and development trend of the above-mentioned wind turbine and the shortcomings of the existing technology.

[0007] The technical objectives of the present invention are achieved through the following technical solutions: a yaw control method for a wind turbine with high efficiency and wind capture, wherein the wind turbine is a horizontal axis wind turbine, a laser radar anemometer is arranged at the front of the nacelle of the wind turbine, and a mechanical wind vane is arranged at the rear of the nacelle;

[0008] The yaw control method is to yaw the wind turbine according to the control sequence of first the normal state of the wind measuring equipment and then the fault state of the wind measuring equipment;

[0009] When the control system detects that the laser radar anemometer and the mechanical wind vane have wind measurement signal inputs, it determines that the wind measurement equipment is in a normal state. The yaw control strategy is:

[0010] Compare the deviation between the wind direction value at a set distance in front of the wind rotor measured by the laser radar anemometer and the wind direction value measured by the mechanical wind vane;

[0011] If the wind direction deviation comparison value is within the set allowable range, the yaw-to-wind action is performed based on the wind direction measured by the laser radar anemometer;

[0012] If the wind direction deviation comparison value is outside the set allowable range, the yaw-to-wind action is performed based on the wind direction measured by the mechanical wind vane;

[0013] When the control system detects that the laser radar anemometer and the mechanical wind vane have only a single wind measurement signal input, it determines that the laser radar anemometer / mechanical wind vane with wind measurement signal input is in a normal state, and determines that the mechanical wind vane / laser radar anemometer without wind measurement signal input is in a fault state. The yaw control strategy is:

[0014] Yaw-to-wind action is performed based on the wind direction measured by the laser radar anemometer / mechanical wind vane with wind measurement signal input;

[0015] When the control system detects that there is no wind measurement signal input from the laser radar anemometer and the mechanical wind vane, it determines that the wind measurement equipment is in a fault state. The yaw control strategy is:

[0016] Step 1. Obtain the current real-time average output power of the wind turbine;

[0017] Compare the deviation between the current real-time output average power and the theoretical output power under the current wind speed;

[0018] If the power deviation comparison value is within the set allowable range, maintain the current wind state;

[0019] If the power deviation comparison value is outside the set allowable range, the yaw to wind action is performed clockwise / counterclockwise according to the set angle;

[0020] Step 2. After completing the yaw-to-wind action, obtain the current real-time average output power of the wind turbine;

[0021] Compare the current real-time output average power 2 with the real-time output average power 1 of the previous cycle;

[0022] If the current real-time output average power 2 is greater than the real-time output average power 1 of the previous cycle, the current real-time output average power 2 is compared with the theoretical output power under the current wind speed for deviation; if the power deviation comparison value is within the set allowable range, the current wind-facing state is maintained; if the power deviation comparison value is outside the set allowable range, the next yaw-facing wind action is performed according to the set angle in the direction of the current yaw-facing wind action;

[0023] If the current real-time output average power 2 is less than the real-time output average power 1 of the previous cycle, the next yaw-to-wind action is performed at the set angle in the opposite direction of the current yaw-to-wind action;

[0024] Repeat step 2 until the real-time output average power in the current yaw-to-wind cycle and the power deviation comparison value of the theoretical output power under the current wind speed are within the set allowable range, and maintain the current wind-to-wind state.

[0025] Preferably, the setting allowable range of the wind direction deviation comparison value is ±5°.

[0026] Preferably, the maximum allowable range for setting the power deviation comparison value is 5% of the theoretical output power under the current wind speed.

[0027] Preferably, the setting angle for performing the yaw-to-wind action clockwise / counterclockwise at a set angle is 3 to 5 degrees.

[0028] Preferably, the theoretical output power satisfies the following relationship: ;

[0029] Where, is the theoretical output power of the wind turbine under the current wind speed;

[0030] is the air density of the current wind farm;

[0031] is the wind speed at the location of the wind turbine;

[0032] is the swept area of ​​the wind turbine rotor;

[0033] is the wind energy utilization coefficient.

[0034] Preferably, the real-time output average power satisfies the following relationship:

[0035] ;

[0036] Where, is the average power of the wind turbine's current real-time output power;

[0037] is the instantaneous power of the wind turbine's current real-time output power;

[0038] The number of samples of the wind turbine's current real-time average output power;

[0039] j is the power value of the jth collection point.

[0040] Preferably, the wind direction value measured by the laser radar anemometer satisfies the following relationship: ;

[0041] Where, The wind direction at the front end of the wind rotor is measured by the laser radar anemometer;

[0042] To set the measurement section within the measurement range of the lidar wind meter;

[0043] is the average wind direction value at the i-th measurement section corresponding to the front end of the wind rotor;

[0044] is the weighted value corresponding to the average wind direction value at the i-th measurement section.

[0045] Furthermore, the laser radar anemometer is used to measure wind condition information of measurement sections at 8 to 12 different measurement distances between 50 and 200 meters from the front end of the wind rotor;

[0046] The wind direction information acquisition frequency of the laser radar anemometer is 1 Hz. The wind direction information measured at the corresponding i-th measurement section is smoothed and filtered according to the following relationship: ;

[0047] Where, is the average wind direction value at the i-th measurement section corresponding to the front end of the wind rotor;

[0048] For the Wind direction sampling data;

[0049] N is the number of samples.

[0050] Preferably, the laser radar anemometer is a coherent Doppler laser radar anemometer;

[0051] The laser radar anemometer emits four laser beams at the left, right, upper and lower positions at the front of the wind turbine cabin. The two laser beams at the left and right positions are coordinated with the central axis of the wind wheel at an angle of 12 to 13 degrees, and the two laser beams at the upper and lower positions are coordinated with the central axis of the wind wheel at an angle of 14 to 16 degrees.

[0052] The beneficial technical effect of the present invention is: the above technical measures are aimed at the particularity and development trend of the above wind turbines, and with the coordinated cooperation of the laser radar anemometer and the mechanical wind vane, under the normal state of the wind measuring equipment, the accuracy of the yaw action of the wind turbine is greatly improved, and it has reliable guidance for the wind turbine to perform the yaw action of high-efficiency wind capture. Specifically, the mechanical wind vane at the rear of the cabin has "lag" and "susceptibility to interference" in measuring wind direction information, while the laser radar anemometer at the front of the cabin can effectively measure the original wind direction within the set distance range of the front end of the wind rotor, thereby reliably correcting and supplementing the wind direction information of the mechanical wind vane received by the control system; the laser radar anemometer at the front of the cabin is easily interfered with by weather factors such as dense fog in measuring wind direction information, while the mechanical wind vane at the rear of the cabin can effectively resist interference from weather factors such as dense fog, thereby reliably correcting and supplementing the wind direction information of the laser radar anemometer received or not received by the control system. It can be seen that the coordinated cooperation between the two eliminates the main interference factors, so that the wind direction information received by the control system is highly accurate, which is conducive to executing efficient wind-catching yaw wind-facing actions and reducing power losses.

[0053] On this basis, when the wind measuring equipment fails and cannot provide wind direction information, the yaw control strategy based on output power comparison can enable the wind turbine to intelligently "self-explore" and efficiently use the wind-catching yaw action to wait for maintenance and rescue during the power generation process, reduce or even avoid power generation interruptions, reduce unnecessary power losses, and also help the wind turbine maintain safe operation.

[0054] Therefore, the yaw control method of the above technical measures can enable the wind turbine to efficiently capture wind, reduce unnecessary power loss, maintain safe operation during service, and achieve significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 Schematic diagram of the flow of the yaw control method of the present invention.

[0056] Figure 2 for Figure 1 Flowchart of executing power bias yaw control program. DETAILED DESCRIPTION

[0057] The present invention relates to the field of wind power generation technology, and in particular to a yaw control method for a wind turbine with high efficiency and wind capture, as shown below in conjunction with the accompanying drawings of the specification - Figure 1 and Figure 2 The technical solution of the present invention is clearly and in detail explained.

[0058] It should be noted that the drawings of the present invention are schematic and have been simplified to clarify the technical objectives of the present invention and to avoid obscuring the present invention's contribution to the prior art. Furthermore, expressions such as "approximately" and "substantially" regarding quantities or fitting relationships below are intended to allow for reasonable assembly and processing errors within the industry and do not literally represent absolute quantities or fitting relationships.

[0059] See also Figure 1 and Figure 2 As shown, the wind turbine yaw control method of the present invention is applicable to a horizontal axis wind turbine, in which a laser radar anemometer is arranged at the front of the nacelle and a mechanical wind vane is arranged at the rear of the nacelle.

[0060] The lidar wind meter uses a coherent Doppler lidar wind meter, which has high temporal and spatial resolution and can obtain detailed three-dimensional wind fields in the atmospheric boundary layer. The lidar wind meter emits four laser beams from the front of the wind turbine nacelle: left, right, top, and bottom. The left and right laser beams are aligned with the rotor's central axis at an angle of approximately 12-13° (typically 12.5°), while the top and bottom laser beams are aligned with the rotor's central axis at an angle of approximately 14-16° (typically 15°).

[0061] Mechanical wind vanes are commonly used in wind turbines.

[0062] The yaw control method of the present invention yaws a wind turbine to the wind in a control sequence that starts with the normal state of the wind measuring equipment and ends with the fault state of the wind measuring equipment. Specifically, the method includes three control states: a first control state in which both the laser radar anemometer and the mechanical wind vane are in a normal state; a second control state in which either the laser radar anemometer or the mechanical wind vane is in a fault state and the other is in a normal state; and a third control state in which both the laser radar anemometer and the mechanical wind vane are in a fault state.

[0063] More specifically, when the control system detects that the laser radar anemometer and the mechanical wind vane have wind measurement signals input, it determines that the laser radar anemometer and the mechanical wind vane are in normal state. The yaw control strategy under this state is (see Figure 1 shown):

[0064] Compare the deviation between the wind direction value at a set distance in front of the wind rotor measured by the laser radar anemometer and the wind direction value measured by the mechanical wind vane;

[0065] If the wind direction deviation comparison value is within the set allowable range (±5°, including 5°), the yaw-to-wind action is performed based on the wind direction measured by the lidar anemometer;

[0066] If the wind direction deviation comparison value is outside the set allowable range (±5°), the yaw wind action is performed based on the wind direction measured by the mechanical wind vane.

[0067] The above-mentioned lidar anemometer is used to measure wind condition information (i.e. wind vector information) at 8 to 12 measurement sections with different measurement distances between 50 and 200 meters from the front end of the wind rotor (i.e., the value of formula 1 is any one of 8 to 12, usually 10).

[0068] The wind direction value measured by the above-mentioned laser radar anemometer satisfies the following relationship (Equation 1):

[0069] Where, The wind direction at the front end of the wind rotor is measured by the laser radar anemometer;

[0070] To set the measurement range of the laser radar wind meter A measurement section, usually 10, but can also be replaced by 8 or 12;

[0071] is the average wind direction value at the i-th measurement section corresponding to the front end of the wind rotor;

[0072] is the weighted value corresponding to the average wind direction value at the i-th measurement section.

[0073] The wind direction information acquisition frequency of the above-mentioned lidar anemometer is 1 Hz. The wind direction information measured at the corresponding i-th measurement section is smoothed and filtered according to the following relationship (Equation 2):

[0074] Where, is the average wind direction value at the i-th measurement section corresponding to the front end of the wind rotor;

[0075] For the Wind direction sampling data;

[0076] N The number of samples is in the range of 8 to 12, and is usually 10.

[0077] The weighted values ​​of the average wind direction values ​​at the corresponding measurement sections are weighted using a well-known Gaussian weight function. The weighted values ​​of the average wind direction values ​​at different measurement sections are shown in the following table:

[0078] According to the above formula 2 and the weighting process, the above formula 1 can be obtained (set Take the value 10), that is, the wind direction value at the front of the fan is: .

[0079] When the control system detects that only one wind signal is input from the laser radar anemometer and the mechanical wind vane (e.g., laser radar anemometer / mechanical wind vane), it determines that the laser radar anemometer / mechanical wind vane with wind signal input is in a normal state, and the mechanical wind vane / lidar anemometer without wind signal input is in a fault state. The yaw control strategy in this state is:

[0080] Yaw-to-wind action is performed based on the wind direction measured by the laser radar anemometer / mechanical wind vane with wind measurement signal input;

[0081] The control system outputs a signal to the monitoring platform in real time indicating that the mechanical wind vane / lidar anemometer is faulty and needs repair.

[0082] When the control system detects that there is no wind measurement signal input from the laser radar anemometer and the mechanical wind vane, it determines that the wind measurement equipment is in a fault state. The yaw control strategy under this state is (see Figure 1 and Figure 2 shown):

[0083] Step 1. The control system obtains the current real-time average output power of the wind turbine according to the following relationship (Equation 3):

[0084] Where, is the average power of the wind turbine's current real-time output power;

[0085] The instantaneous power of the wind turbine's current real-time output power (obtained by the output power monitoring device on the wind turbine);

[0086] The number of samples of the wind turbine's current real-time output average power is in the range of 8 to 12, and is usually 10.

[0087] j is the power value of the jth collection point;

[0088] Compare the deviation between the current real-time output average power and the theoretical output power under the current wind speed;

[0089] The theoretical output power satisfies the following relationship (Equation 4):

[0090] Where, is the theoretical output power of the wind turbine under the current wind speed;

[0091] is the air density of the current wind farm;

[0092] is the wind speed at the location of the wind turbine;

[0093] is the swept area of ​​the wind turbine rotor;

[0094] is the wind energy utilization coefficient;

[0095] If the power deviation comparison value is within the set allowable range (the set allowable range value The maximum is 5% of the theoretical output power under the current wind speed, excluding 5% of the theoretical output power), that is, , it indicates that the current high-efficiency wind capture has been basically achieved, and the current wind-facing state can be maintained;

[0096] If the power deviation comparison value is within the set allowable range (the set allowable range value In addition to the maximum of 5% of the theoretical output power under the current wind speed, the yaw action is performed clockwise / counterclockwise at a set angle (such as 5° or 3°, etc., with a value between 3 and 5°) to find high-efficiency wind capture;

[0097] Step 2. After completing the yaw-to-wind action, obtain the current real-time average output power of the wind turbine according to Equation 3;

[0098] Compare the current real-time output average power 2 with the real-time output average power 1 of the previous cycle;

[0099] If the current real-time output average power 2 is greater than the real-time output average power 1 of the previous cycle, it indicates that the yaw wind direction is correct. The current real-time output average power 2 is compared with the theoretical output power under the current wind speed according to formula 4. If the power deviation comparison value is within the set allowable range, it indicates that high-efficiency wind capture has been basically achieved and the current wind-facing state can be maintained. If the power deviation comparison value is outside the set allowable range, the wind-facing action of the next yaw cycle is performed according to the set angle in the direction of the current yaw wind-facing action.

[0100] If the current real-time output average power is less than the real-time output average power of the previous cycle, it means that the yaw direction is wrong and the wind direction should be reversed to the direction of the current yaw action and the wind direction of the next yaw cycle should be performed according to the set angle.

[0101] Repeat step 2 until the real-time output average power in the current yaw-facing wind cycle and the power deviation comparison value of the theoretical output power under the current wind speed are within the set allowable range, indicating that high-efficiency wind capture has basically been achieved and the current wind-facing state can be maintained.

[0102] Of course, when the control system controls the yaw action to the wind based on the output power comparison, it outputs a signal to the monitoring platform in real time that the mechanical wind vane and the laser radar anemometer are both faulty and need to be repaired.

[0103] The above specific technical solutions are only used to illustrate the present invention rather than to limit it.

[0104] Although the present invention has been described in detail with reference to the above-mentioned specific technical solutions, those skilled in the art should understand that they can still modify the above-mentioned specific technical solutions or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the present invention.

Claims

1. A method for efficiently catching wind in a yaw control of a wind turbine, wherein the wind turbine is a horizontal-axis wind turbine, a laser radar anemometer is arranged at the front of the nacelle of the wind turbine, and a mechanical wind vane is arranged at the rear of the nacelle; It is characterized in that The yaw control method is to yaw the wind turbine according to the control sequence of first the normal state of the wind measuring equipment and then the fault state of the wind measuring equipment; When the control system detects that the laser radar anemometer and the mechanical wind vane have wind measurement signal inputs, it determines that the wind measurement equipment is in a normal state. The yaw control strategy is: Compare the deviation between the wind direction value at a set distance in front of the wind rotor measured by the laser radar anemometer and the wind direction value measured by the mechanical wind vane; If the wind direction deviation comparison value is within the set allowable range, the yaw-to-wind action is performed based on the wind direction measured by the laser radar anemometer; If the wind direction deviation comparison value is outside the set allowable range, the yaw-to-wind action is performed based on the wind direction measured by the mechanical wind vane; When the control system detects that the laser radar anemometer and the mechanical wind vane have only a single wind measurement signal input, it determines that the laser radar anemometer / mechanical wind vane with wind measurement signal input is in a normal state, and determines that the mechanical wind vane / laser radar anemometer without wind measurement signal input is in a fault state. The yaw control strategy is: Yaw-to-wind action is performed based on the wind direction measured by the laser radar anemometer / mechanical wind vane with wind measurement signal input; When the control system detects that there is no wind measurement signal input from the laser radar anemometer and the mechanical wind vane, it determines that the wind measurement equipment is in a fault state. The yaw control strategy is: Step 1. Obtain the current real-time average output power of the wind turbine; Compare the deviation between the current real-time output average power and the theoretical output power under the current wind speed; If the power deviation comparison value is within the set allowable range, maintain the current wind state; If the power deviation comparison value is outside the set allowable range, the yaw to wind action is performed clockwise / counterclockwise according to the set angle; Step 2. After completing the yaw-to-wind action, obtain the current real-time average output power of the wind turbine; Compare the current real-time output average power 2 with the real-time output average power 1 of the previous cycle; If the current real-time output average power 2 is greater than the real-time output average power 1 of the previous cycle, the current real-time output average power 2 is compared with the theoretical output power under the current wind speed for deviation; if the power deviation comparison value is within the set allowable range, the current wind-facing state is maintained; if the power deviation comparison value is outside the set allowable range, the next yaw-facing wind action is performed according to the set angle in the direction of the current yaw-facing wind action; If the current real-time output average power 2 is less than the real-time output average power 1 of the previous cycle, the next yaw-to-wind action is performed at the set angle in the opposite direction of the current yaw-to-wind action; Repeat step 2 until the real-time output average power in the current yaw-facing wind cycle and the power deviation comparison value of the theoretical output power under the current wind speed are within the set allowable range, and maintain the current wind-facing state; The setting angle for performing the yaw to wind action clockwise / counterclockwise at the set angle is 3 to 5 degrees; The wind direction value measured by the laser radar anemometer satisfies the following relationship: ; Where, The wind direction at the front end of the wind rotor is measured by the laser radar anemometer; To set the measurement range of the laser radar wind meter measurement sections; is the average wind direction value at the i-th measurement section corresponding to the front end of the wind rotor; is the weighted value corresponding to the average wind direction value at the i-th measurement section.

2. The yaw control method for a wind turbine with high efficiency and wind capture according to claim 1, characterized in that: The allowable setting range of the wind direction deviation comparison value is ±5°.

3. The yaw control method for a wind turbine with high efficiency and wind capture according to claim 1, characterized in that: The maximum allowable range for setting the power deviation comparison value is 5% of the theoretical output power under the current wind speed.

4. The yaw control method for a wind turbine with high efficiency and wind capture according to claim 1, characterized in that: The theoretical output power satisfies the following relationship: ; Where, is the theoretical output power of the wind turbine under the current wind speed; is the air density of the current wind farm; is the wind speed at the location of the wind turbine; is the swept area of ​​the wind turbine rotor; is the wind energy utilization coefficient.

5. The yaw control method for a wind turbine with high efficiency and wind capture according to claim 1, characterized in that: The real-time output average power satisfies the following relationship: ; Where, The current real-time average output power of the wind turbine; is the instantaneous power of the wind turbine's current real-time output power; The number of samples of the wind turbine's current real-time average output power; j is the power value of the jth collection point.

6. The yaw control method for a wind turbine with high efficiency and wind capture according to claim 1, characterized in that: The laser radar anemometer is used to measure wind condition information at 8 to 12 different measurement distances between 50 and 200 meters from the front end of the wind rotor; The wind direction information acquisition frequency of the laser radar anemometer is 1 Hz. The wind direction information measured at the corresponding i-th measurement section is smoothed and filtered according to the following relationship: ; Where, is the average wind direction value at the i-th measurement section corresponding to the front end of the wind rotor; For the Wind direction sampling data; N is the number of samples.

7. The yaw control method for a wind turbine with high efficiency and wind capture according to claim 1, characterized in that: The laser radar anemometer is a coherent Doppler laser radar anemometer; The laser radar anemometer emits four laser beams at the left, right, upper and lower positions at the front of the wind turbine cabin. The two laser beams at the left and right positions are coordinated with the central axis of the wind wheel at an angle of 12 to 13 degrees, and the two laser beams at the upper and lower positions are coordinated with the central axis of the wind wheel at an angle of 14 to 16 degrees.

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