Wind generating set compliant yaw control method based on variable speed curve

Abstract

The invention relates to a wind generating set compliant yaw control method based on a variable speed curve. The method comprises the following steps that current wind direction changes are predicted based on the numerical simulation technology and a wind direction and wind speed database; on the basis of the obtained wind direction change predicted value, the optimal yaw direction and angle are obtained through calculation; a variable-speed yaw curve is designed according to the optimal yaw direction and angle, and flexible start-stop control is achieved according to the designed variable-speed yaw curve; according to the method, the yaw speed change trajectory curve based on wind direction prediction and combined with the genetic algorithm is designed, and smooth start and stop of yaw control of the wind generating set are achieved under the working condition of considering yaw efficiency and precision.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a flexible yaw control method of a wind power generator set based on a speed change curve. Background Art

[0002] When the wind direction changes, the wind turbine needs to complete the yaw action through the yaw system to make the wind turbine face the wind direction to ensure the maximum utilization of wind energy. Therefore, the yaw system is an important part of the wind turbine, and its yaw stability and accuracy affect the power generation efficiency and stability of the wind turbine.

[0003] The main function of the yaw control system in wind power generation technology is to ensure the safe and stable operation of the wind turbine generator set, so as to increase the wind energy conversion efficiency of the wind power generation system, and thus save the initial investment of the wind power generation system. It is generally composed of detection elements, control parts, actuators and wind turbines. The working principle of the yaw control system is: each yaw direction has a corresponding pulse output signal through the wind direction sensor element, the yaw direction and yaw angle are determined by the yaw system software, and the wind direction sensor element sends the wind direction signal to the processor of the control cabinet of the cabin. After comparison by the yaw system adjustment software, the processor will send a forward or reverse command to the yaw motor, which will act on the large gear of the rotating body after being decelerated by the reducer on the motor shaft, driving the cabin to rotate, and stop working after completing the wind work. However, the wind turbine generator set faces the instability of vibration caused by rapid yaw start and stop, which accelerates the wear of the brake pads and produces harsh noise and strong vibration. Therefore, a yaw smooth start and stop control method is needed to address this problem. Reference patent CN109653949B proposes a yaw method for a wind turbine generator set with electromagnetic damping provided by a yaw motor, which provides a reverse resistance torque through hydraulic variable damping to achieve a relatively smooth yaw action. For example, reference patent CN112253389B proposes a start-stop control method for a yaw control system of a wind turbine generator set, which takes into account the vibration effect caused by the change in the speed of the belt motor.

[0004] Although the above control method can improve the compliance of the yaw of the wind turbine, it still has some shortcomings and limitations: although the start-stop process can be made smoother by adding a matching hydraulic variable damping system to provide reverse torque, it will lead to more energy consumption in the adjustment, and the cost will increase and the possibility of failure will increase due to the addition of the system; the yaw buffeting problem can be initially improved through a simple variable acceleration or deceleration curve, but there is a lack of further optimization of the yaw curve, and it is impossible to achieve both efficient and precise yaw action. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a method for flexible yaw control of a wind turbine generator set based on a variable speed curve. The method designs a variable speed curve based on wind direction prediction to achieve flexible yaw control of the wind turbine generator set.

[0006] To achieve the above object, the present invention adopts the following technical solution: a wind turbine generator set compliant yaw control method based on a variable speed curve, comprising the following steps:

[0007] Step 1: Predict the current wind direction change based on numerical simulation technology and wind direction and speed database;

[0008] Step 2: Based on the predicted value of wind direction change, calculate the yaw direction and angle;

[0009] Step 3: Design a speed-changing yaw curve according to the optimal yaw direction and angle, and implement smooth start-stop control according to the designed speed-changing yaw curve.

[0010] In a preferred embodiment, step 1 is implemented as follows:

[0011] Wind direction information is collected through wind direction sensors, and the current wind direction change trend is calculated by the autoregressive moving average model (ARMA) based on time series analysis. The wind direction information is compared with the wind direction and speed database to determine the feasibility of the calculated wind direction change prediction. When the predicted value coincides with the database data by more than 80%, the predicted value is used as the final stable wind direction prediction value.

[0012] In a preferred embodiment, the autoregressive moving average model method based on time series analysis in step 1 is as follows:

[0013] The collected wind direction data are preprocessed to remove abnormal data exceeding 80% of the data mean, and the orders p and q of ARMA are determined by the autocorrelation function and the partial autocorrelation function. The parameters of the ARMA are estimated by combining the maximum likelihood estimation method to obtain the database-based ARMA.

[0014] In a preferred embodiment, the yaw direction and angle are determined in step 2 as follows:

[0015] When the angle between the stable wind direction and the normal direction of the wind rotor windward surface is less than 180°, the wind turbine nacelle turns clockwise, and the yaw angle θ e for:

[0016] θ e =θ w -θ T (1)

[0017] In the formula, θ w is the predicted value of stable wind direction; θ Tis the rotor angle. Since the wind direction angle is usually the angle relative to the normal direction of the windward surface of the rotor, its value is zero.

[0018] When the angle between the stable wind direction and the normal direction of the wind rotor windward surface is greater than 180°, the wind turbine nacelle turns counterclockwise, and the yaw angle θ e for:

[0019] θ e =360°-|θ w -θ T |=360°-θ w (2).

[0020] In a preferred embodiment, the variable speed yaw curve design method in step 3 is:

[0021] A high-order polynomial curve shown in formula (3) is used as the wind turbine yaw speed change curve; at the same time, the smooth start and smooth end of the yaw action are used as boundary conditions for the corresponding area;

[0022] The yaw action is discretized into equal distances, and the obtained discrete trajectory θ(t) is:

[0023]

[0024] For the equally spaced connection points θ(t j ) retains the trajectory deviation floating value Δθ j To improve the flexibility of the trajectory, the command value of each segment is θ(t j )=θ bj +Δθ j ;

[0025] In formula (3), is the polynomial coefficient of each speed change interval; m is the highest degree of the polynomial; n is the number of intervals; i = 0, 1, 2, ..., m, j = 0, 1, 2, ..., n-1; t0 is the start time of wind turbine yaw, t n is the wind turbine yaw end time; θ bj For j The command value at the time, Δθ j is the corresponding deviation floating value.

[0026] In a preferred embodiment, Δθ j The design method for the corresponding deviation floating value is:

[0027] Through genetic algorithm, the elite strategy and migration strategy are combined to optimize the deviation floating point value under the goal of smoothness in the yaw start and stop phase. The node floating point value [Δθ k1 Δθ k2 ...Δθ kn] performs a global search for the minimum fitness function value, where k is the number of iterations. The specific method of optimizing the deviation floating point value through the genetic algorithm is:

[0028] S1: Each generation of floating point values ​​[Δθ k1 Δθ k2 ...Δθ kn ], and combined with the spline interpolation function to generate a high-order spline interpolation trajectory;

[0029] S2: Input the generated high-order spline interpolation trajectory into the fan system and calculate the fitness function value.

[0030] In a preferred embodiment, the fitness function is designed as:

[0031]

[0032] In the formula, t s is the duration of the wind turbine yaw process; e p (t) is the difference between the actual yaw angle and the expected yaw trajectory angle; r i is the coefficient factor of each penalty term; P i (u) is the sum of the floating value of the current fan motor yaw angle and the basic expected yaw angle of the fan motor. j ) is the penalty term when it exceeds the control range of the command signal.

[0033] In a preferred embodiment: after the speed change curve is calculated, the speed change trajectory curve is input into the motor controller as the expected curve. When the motor controller completes the curve reception, the yaw brake is released, and the motor controls the drive motor according to the expected speed change curve. The drive motor outputs the yaw torque to complete the yaw action through the reduction gear box. When the yaw angle reaches the expected yaw value, the motor stops running, the yaw brake is applied to complete the yaw action.

[0034] Compared with the prior art, the present invention has the following beneficial effects: the present invention proposes a wind turbine yaw control method based on a variable speed curve for a wind turbine, which can generate a variable speed yaw curve optimized by a genetic algorithm on the premise of predicting wind direction changes, realize a flexible yaw start-stop action, and ensure yaw accuracy and efficiency. Its significant advantages include:

[0035] 1) Based on the real-time numerical simulation technology and the wind direction and speed database, the wind direction change trend is predicted to provide precise guidance for yaw action.

[0036] 2) The yaw angle and direction of the current wind rotor windward side are determined by the wind direction prediction value, providing a basis for efficient yaw trajectory planning.

[0037] 3) A polynomial speed change curve is proposed to plan the yaw trajectory, and based on the requirements of smooth start and stop, a genetic algorithm is combined to search for the minimum fitness value function of the segmented trajectory to improve the flexibility of the entire yaw process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention is a flowchart of a method implementation of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0042] like Figure 1 As shown, this embodiment provides a wind turbine generator set compliant yaw control method based on a variable speed curve, comprising the following steps:

[0043] Step 1: Predict the current wind direction change based on numerical simulation technology and wind direction and speed database;

[0044] Step 2: Based on the predicted value of wind direction change, calculate the optimal yaw direction and angle;

[0045] Step 3: Design a variable speed yaw curve according to the optimal yaw direction and angle, and realize smooth start-stop control according to the designed variable speed yaw curve;

[0046] In the embodiment, the method for predicting the wind direction change in step 1 is as follows:

[0047] The wind direction information within 5 seconds is collected by the wind direction sensor, and the current wind direction change trend is calculated by the autoregressive moving average model (ARMA) based on time series analysis. The feasibility of the calculated wind direction change prediction is judged by comparing it with the wind direction and wind speed database. When the predicted value coincides with the database data by more than 80%, the predicted value is taken as the final stable wind direction prediction value.

[0048] In step 1 of the embodiment, the autoregressive moving average model method based on time series analysis is as follows:

[0049] The collected wind direction data are preprocessed to remove abnormal data exceeding 80% of the data mean, and the orders p and q of ARMA are determined by the autocorrelation function and the partial autocorrelation function. The parameters of the ARMA are estimated by combining the maximum likelihood estimation method to obtain the database-based ARMA.

[0050] In the embodiment, the yaw direction and angle are determined in step 2 as follows:

[0051] When the angle between the stable wind direction and the normal direction of the wind rotor windward surface is less than 180°, the wind turbine nacelle turns clockwise, and the yaw angle is:

[0052] θ e =θ w -θ T (1)

[0053] In the formula, θ w is the predicted value of stable wind direction; θ T is the rotor angle. Since the wind direction angle is usually the angle relative to the normal direction of the wind rotor windward surface, its value is zero.

[0054] When the angle between the stable wind direction and the normal direction of the wind rotor windward surface is greater than 180°, the wind turbine nacelle turns counterclockwise, and the yaw angle is:

[0055] θ e =360°-|θ w -θ T |=360°-θ w (2)

[0056] In the embodiment, the speed change yaw curve design method described in step 3 is:

[0057] A high-order polynomial curve is used as the wind turbine yaw speed change curve. At the same time, the smooth start and end of yaw action are used as boundary conditions for the corresponding area.

[0058] The yaw action is discretized into equal distances, and the obtained discrete trajectory θ(t) is:

[0059]

[0060] For the equally spaced connection points θ(t j ) retains the trajectory deviation Δθ j To improve the flexibility of the trajectory, the command value of each segment is θ(t j )=θ bj +Δθ j .

[0061] In formula (3), is the polynomial coefficient of each speed change interval; m is the highest degree of the polynomial; n is the number of intervals; i = 0, 1, 2, ..., m, j = 0, 1, 2, ..., n-1; t0 is the start time of wind turbine yaw, t n is the wind turbine yaw end time; θ bj For j The command value at the time, Δθ j is the corresponding deviation floating value.

[0062] In the embodiment Δθ j The design method for the corresponding deviation floating value is:

[0063] Through the genetic algorithm toolbox configured by Matlab, the elite strategy and the migration strategy are combined to optimize the deviation floating point value under the goal of smoothness in the yaw start and stop phase, and the node floating point value [Δθ k1 Δθ k2 ...Δθ kn ] performs a global search for the minimum fitness function value, where k is the number of iterations. The specific method is:

[0064] S1: The floating point values ​​[Δθ k1 Δθ k2 ...Δθ kn ] is passed to the m file of Matlab, and combined with the spline interpolation function to generate a high-order spline interpolation trajectory.

[0065] S2: Input the generated high-order spline interpolation trajectory into the fan system and calculate the fitness function value;

[0066] In the embodiment, the fitness function is designed as:

[0067]

[0068] In the formula, t s is the duration of the wind turbine yaw process; e p (t) is the difference between the actual yaw angle and the expected yaw trajectory angle; r i is the coefficient factor of each penalty term; P i (u) is the sum of the floating value of the current fan motor yaw angle and the basic expected yaw angle of the fan motor. j ) is the penalty term when it exceeds the control range of the command signal.

[0069] In an embodiment, the maximum number of times the polynomial discretization trajectory is discretized is 5, the number of segments of the equidistant discretization processing is 5 to 10, the number of elite individuals in the global optimization of the genetic algorithm is set to 5% of the total individuals, and the number of migration interval generations is set to 15 generations.

[0070] In the embodiment, the yaw action after the speed change curve is generated is as follows: when the speed change curve is calculated, the speed change trajectory curve is input into the motor controller as the expected curve; when the motor controller completes the curve reception, the yaw brake is released, and the motor controls the drive motor according to the expected speed change curve; the drive motor outputs the yaw torque to complete the yaw action through the reduction gear box; when the yaw angle reaches the expected yaw value, the motor stops running, the yaw brake is braked, and the yaw action is completed.

Claims

1. A wind turbine generator set compliant yaw control method based on a variable speed curve, characterized in that: The following steps are involved: Step 1: Predict the current wind direction change based on numerical simulation technology and wind direction and speed database; Step 2: Based on the predicted value of wind direction change, calculate the yaw direction and angle; Step 3: Design a speed-changing yaw curve according to the optimal yaw direction and angle, and implement smooth start-stop control according to the designed speed-changing yaw curve.

2. The method for controlling the compliant yaw of a wind turbine generator set based on a speed change curve according to claim 1, characterized in that: Step 1 is implemented as follows: Wind direction information is collected through wind direction sensors, and the current wind direction change trend is calculated by the autoregressive moving average model ARMA based on time series analysis. The wind direction and wind speed database is used to compare the calculated wind direction change prediction to determine the feasibility of the wind direction change prediction. When the predicted value coincides with the database data by more than 80%, the predicted value is used as the final stable wind direction prediction value.

3. The method for controlling the compliant yaw of a wind turbine generator set based on a speed change curve according to claim 1, characterized in that: The autoregressive moving average model method based on time series analysis in step 1 is as follows: The collected wind direction data are preprocessed to remove abnormal data exceeding 80% of the data mean, and the orders p and q of ARMA are determined by the autocorrelation function and the partial autocorrelation function. The parameters of the ARMA are estimated by combining the maximum likelihood estimation method to obtain the database-based ARMA.

4. The method for controlling the compliant yaw of a wind turbine generator set based on a speed change curve according to claim 1, characterized in that: The yaw direction and angle are determined in step 2 as follows: When the angle between the stable wind direction and the normal direction of the wind rotor windward surface is less than 180°, the wind turbine nacelle turns clockwise, and the yaw angle θ e for: i e =θ w -θ T (1) In the formula, θ w is the predicted value of stable wind direction; θ T is the rotor angle. Since the wind direction angle is usually the angle relative to the normal direction of the windward surface of the rotor, its value is zero. When the angle between the stable wind direction and the normal direction of the wind rotor windward surface is greater than 180°, the wind turbine nacelle turns counterclockwise, and the yaw angle θ e for: i e =360°-|θ w -θ T |=360°-θ w (2)。 5. The method for controlling the compliant yaw of a wind turbine generator set based on a speed change curve according to claim 1, characterized in that: The design method of the variable speed yaw curve in step 3 is: A high-order polynomial curve shown in formula (3) is used as the wind turbine yaw speed change curve; At the same time, the boundary conditions of the corresponding area are set by the smooth start and the smooth end of the yaw action; The yaw action is discretized into equal distances, and the obtained discrete trajectory θ(t) is: For the equally spaced connection points θ(t j ) retains the trajectory deviation floating value Δθj to improve the flexibility of the trajectory, so the command value of each segment is θ(t j )=θ bj +Δθ j ; In formula (3), is the polynomial coefficient of each speed change interval; m is the highest degree of the polynomial; n is the interval number; i=0,1,2,…,m, j=0,1,2,…,n-1; t0 is the start time of wind turbine yaw, t n is the wind turbine yaw end time; θ bj For j The command value at the time, Δθ j is the corresponding deviation floating value.

6. The method for controlling the compliant yaw of a wind turbine generator set based on a speed change curve according to claim 4, characterized in that: Δθ j The design method for the corresponding deviation floating value is: Through genetic algorithm, the elite strategy and migration strategy are combined to optimize the deviation floating point value under the goal of smoothness in the yaw start and stop phase. The node floating point value [Δθ k1 Δθ k2 ...Δθ kn ] performs a global search for the minimum fitness function value, where k is the number of iterations; the specific method of optimizing the deviation floating point value through the genetic algorithm is: S1: Each generation of floating point values ​​[Δθ k1 Δθ k2 ...Δθ kn ], and combined with the spline interpolation function to generate a high-order spline interpolation trajectory; S2: Input the generated high-order spline interpolation trajectory into the fan system and calculate the fitness function value.

7. The method for controlling the compliant yaw of a wind turbine generator set based on a speed change curve according to claim 5, characterized in that: The fitness function is designed as: Where, t s is the duration of the wind turbine yaw process; e p (t) is the difference between the actual yaw angle and the expected yaw trajectory angle; r i is the coefficient factor of each penalty term; P i (u) is the sum of the floating value of the current fan motor yaw angle and the basic expected yaw angle of the fan motor. j ) is the penalty term when it exceeds the control range of the command signal.

8. The method for controlling the compliant yaw of a wind turbine generator set based on a speed change curve according to claim 1, characterized in that: When the speed change curve is calculated, the speed change trajectory curve is input into the motor controller as the expected curve. When the motor controller completes the curve reception, the yaw brake is released, and the motor controls the drive motor according to the expected speed change curve. The drive motor outputs the yaw torque through the reduction gearbox to complete the yaw action. When the yaw angle reaches the expected yaw value, the motor stops running, the yaw brake is applied to complete the yaw action.

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