Lidar-based anti-disturbance composite fan variable pitch control method and system

Abstract

The application relates to a laser radar-based anti-interference composite fan variable-pitch control method and system, and belongs to the field of wind turbine control. The method comprises the following steps: acquiring actual rotating speed of a fan rotor and wind speed information measured by a laser radar, and calculating equivalent wind speed of a blade wheel surface according to the wind speed information; calculating a pitch angle corresponding to the wind speed according to fan aerodynamic characteristics and the wind speed information, fitting the pitch angle to obtain a steady-state relationship curve, further obtaining a steady-state pitch angle corresponding to the equivalent wind speed of the blade wheel surface, and combining the actual pitch angle to calculate a feedforward pitch angle; obtaining a self-anti-interference control amount according to the actual rotating speed of the fan rotor and a given fan reference rotating speed; compensating the self-anti-interference control amount by using the feedforward pitch angle to obtain a pitch angle given value; limiting the speed and angle of the pitch angle given value according to the actual operating condition of the fan to obtain a final execution pitch angle. The application can improve the dynamic response of the fan, improve the operating stability of the self-anti-interference system, and improve the control precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wind turbine control, in particular to a laser radar-based anti-disturbance composite wind turbine variable pitch control method and system. BACKGROUND

[0002] In the wind turbine control process, the traditional variable pitch control method relies on feedback control and cannot respond quickly to changes in wind speed. How to accurately obtain wind speed information is the key to control design. Compared with the traditional wind sensor installed at the rear end of the nacelle, the laser wind radar can measure the wind speed in front of the wind wheel in advance. As a technology that can accurately perceive wind parameters with a certain time margin, laser radar wind measurement plays an important role in wind turbine yaw correction, wind turbine power curve testing, intelligent feedforward control and other wind power fields, and has important value for improving wind turbine power generation efficiency, reducing wind turbine load and failure rate, and prolonging wind turbine service life.

[0003] Above the rated wind speed, the wind turbine variable pitch control system reduces the wind energy utilization rate by increasing the blade pitch angle to control the output power to remain at the rated value. Currently, many wind power manufacturers generally use classic PID controllers in variable pitch control. This feedback controller is widely used because of its simple operation and strong stability, but the control parameters are difficult to adjust and lack adaptive characteristics, which leads to poor performance of traditional PID control in dynamic response. Applying active disturbance rejection control to the variable pitch controller can effectively suppress the motor speed deviation under random wind disturbance. In addition, due to the uncertainty of wind speed and the nonlinear characteristics of wind turbine systems, it is extremely difficult to accurately control the wind turbine pitch system. Using feedforward control and using wind speed information to make wind turbines mobilize the pitch and yaw systems in advance can significantly optimize the efficiency of variable pitch control. In feedforward control, it is crucial to obtain accurate wind speed information. In recent years, the rapid development of laser radar wind measurement technology has made it widely used in large-scale wind power control. Compared with using estimators and observers to estimate wind speed, laser radar can provide more accurate wind speed data.

[0004] However, the key to control efficiency is not only the advance perception in spatial dimension, but also the accurate coordination of wind speed signal in time domain. The significant defect of existing research is the lack of systematic consideration of how to introduce the forward-looking information captured by the laser radar into the control system at the right time, which makes it difficult to convert the predictive value of wind speed information into actual control gain. SUMMARY

[0005] Therefore, it is necessary to provide a laser radar-based anti-disturbance composite wind turbine variable pitch control method and system to significantly improve the dynamic response of the wind turbine, improve the operation stability of the active disturbance rejection system, and have higher control accuracy, effectively reducing the fluctuations of output power and wind wheel speed.

[0006] In a first aspect, embodiments of this application provide an anti-interference composite wind turbine pitch control method based on lidar, including:

[0007] The actual rotational speed of the wind turbine rotor and the wind speed information measured by lidar are obtained, and the equivalent wind speed on the impeller surface is calculated based on the wind speed information.

[0008] Based on the aerodynamic characteristics of the wind turbine and wind speed information, the pitch angle corresponding to the wind speed is calculated and fitted to obtain the steady-state relationship curve;

[0009] The steady-state pitch angle corresponding to the equivalent wind speed on the impeller surface is obtained by the steady-state relationship curve, and the feedforward pitch angle is calculated based on the steady-state pitch angle and the actual pitch angle.

[0010] Given the reference speed of the wind turbine, the active disturbance rejection control quantity is obtained based on the actual speed of the wind turbine rotor and the reference speed of the wind turbine.

[0011] The feedforward pitch angle is used to compensate for the active disturbance rejection control variable, and the pitch angle setpoint is obtained.

[0012] Based on the actual operating conditions of the wind turbine, the speed and angle limits are applied to the given pitch angle to obtain the final executed pitch angle.

[0013] In one embodiment, the method for calculating the equivalent wind speed on the impeller surface is as follows:

[0014] Obtain the radial wind speed of the four beams of the lidar at a set distance;

[0015] The combined wind speed of the upper beam and the combined wind speed of the lower beam are calculated based on the radial wind speed.

[0016] The equivalent wind speed on the impeller surface is obtained by calculating the average of the combined wind speed of the upper and lower beams.

[0017] In one embodiment, the formula for calculating the upper beam synthesized wind speed is as follows:

[0018] ;

[0019] in, To synthesize the lateral component of the wind speed using the upper beam, For the longitudinal component of the wind speed synthesized by the upper beam, The horizontal subtended angles of the four beams, The vertical subtraction angles of the four beams, , The radial wind speed of the beam at a set distance. The wind speed is the composite wind speed of the upper beam.

[0020] In one embodiment, the formula for calculating the lower beam synthesized wind speed is as follows:

[0021] ;

[0022] in, To synthesize the lateral component of the wind speed in the lower beam, For the longitudinal component of the wind speed synthesized by the lower beam, , The radial wind speed of the beam at a set distance. The wind speed is the composite wind speed of the lower beam.

[0023] In one embodiment, the method for obtaining the steady-state relationship curve is as follows:

[0024] Set the wind speed variation step size and rated power;

[0025] Based on the wind speed variation step size and rated power, calculate the pitch angle of each wind speed within the wind speed range from rated wind speed to cut-out wind speed.

[0026] Steady-state relationship curves are obtained by polynomial fitting based on each wind speed and the corresponding blade pitch angle.

[0027] In one embodiment, the method for calculating the pitch angle is as follows:

[0028] The initial pitch angle and output power are calculated by substituting the wind speed and rated power into the OpenFAST wind turbine model;

[0029] The initial pitch angle is obtained by adjusting the reference pitch PI controller;

[0030] Determine whether the difference between the output power and the rated power is less than the first set value;

[0031] When the difference between the output power and the rated power is greater than or equal to the first set value, the initial pitch angle is adjusted using the reference pitch PI controller to obtain the pitch angle.

[0032] When the difference between the output power and the rated power is less than the first set value, the pitch angle is the pitch angle corresponding to the wind speed.

[0033] Determine if the wind speed change step size is equal to the second set value.

[0034] When the wind speed change step size is not equal to the second set value, the wind speed change step size is increased by one.

[0035] Repeat the above steps until the wind speed change step size equals the second set value;

[0036] When the wind speed change step size is equal to the second set value, the pitch angle of each wind speed is obtained.

[0037] In one embodiment, the method for obtaining the active disturbance rejection control quantity is as follows:

[0038] Wind turbine-based rotor drive model:

[0039] ;

[0040] In the formula, The equivalent moment of inertia of the wind turbine rotor. This refers to the aerodynamic torque of the fan. This refers to the generator torque of the wind turbine. This refers to the rotor speed of the fan impeller. The collective blade pitch angle of the wind turbine. For wind speed, For the gearbox speed ratio, , This refers to the rotor speed of the wind turbine's generator. This is the first derivative of the impeller rotor speed;

[0041] Taylor expansion of the aerodynamic torque at the steady-state operating point of the wind turbine yields the locally linearized result of the aerodynamic torque variation:

[0042] ;

[0043] in, , , , ;

[0044] In the formula, This is for aerodynamic torque error. The aerodynamic torque at the steady-state operating point of the fan. For impeller rotor speed error, The impeller rotor speed at the steady-state operating point of the fan. This is the error in the pitch angle. The pitch angle at the steady-state operating point of the wind turbine. To account for wind speed estimation error, The wind speed at the steady-state operating point of the fan. is a higher-order infinitesimal in the Taylor expansion. Let be the partial derivative of torque with respect to impeller rotor speed. This is the partial derivative of the torque with respect to the pitch angle. This is the partial derivative of torque with respect to wind speed;

[0045] make , , Based on the partial derivative values ​​of the torque, combined with the formula , will Rewritten as:

[0046] ;

[0047] in, This is the second derivative of the impeller rotor speed error; , The time constant of the pitch system, This is a control value for the pitch angle; The total disturbance of the pitch system is expressed as:

[0048] ;

[0049] in, The derivative of the impeller rotor speed error. The derivative of the wind speed estimation error. The derivative of the generator torque error. This refers to the generator torque error. is the derivative of the higher-order terms in the Taylor expansion;

[0050] Based on the principle of active disturbance rejection control, and using the disturbance estimation based on the gray box method, a state-space model of the total disturbance is obtained.

[0051] The linear extended state observer is designed based on the state-space model of the total disturbance as follows:

[0052] ;

[0053] in, , , For the state variables of a linearly extended state observer, for The derivative, for The derivative, for The derivative, This is the output of the state-space model of the total disturbance. , , The parameter to be adjusted;

[0054] Let the gain matrix be... Then it can be adjusted using the following formula:

[0055] ;

[0056] in, For complex variables, It is the identity matrix. The system matrix in the state-space model. For the output matrix, The expected bandwidth of the linearly extended state observer;

[0057] Based on a linear extended state observer and using a linear state feedback controller, the expression for the active disturbance rejection control quantity is obtained:

[0058] ;

[0059] in, ;

[0060] In the formula, This is the active disturbance rejection control variable. For virtual control variables, This is the reference speed for the fan. , Let the controller gain matrix be the parameters of the controller to be designed. Then it satisfies ;

[0061] in, The state matrix, , For the input matrix, , The bandwidth of the controller to be designed.

[0062] In one embodiment, the method for obtaining the state-space model of the total disturbance is as follows:

[0063] Based on the principle of active disturbance rejection control, three state variables are selected as follows: , , The state-space model of the total disturbance is obtained as follows:

[0064] ;

[0065] in, , , They are respectively , , The derivative, for The derivative;

[0066] Based on the disturbance estimation using the gray box method, the total disturbance of the pitch system is obtained. It can be represented as:

[0067] ;

[0068] In the formula:

[0069] ;

[0070] ;

[0071] in, For estimable terms, This is an unknown disturbance.

[0072] Secondly, embodiments of this application provide an anti-interference composite wind turbine pitch control system based on lidar, comprising:

[0073] The acquisition module is used to acquire wind speed information measured by lidar and to acquire the actual rotational speed of the wind turbine rotor;

[0074] The feedforward control module, connected to the acquisition module, is configured to: calculate the equivalent wind speed of the impeller surface based on the wind speed information; calculate the pitch angle corresponding to the wind speed based on the aerodynamic characteristics of the fan and the wind speed information, and fit it to obtain a steady-state relationship curve; obtain the steady-state pitch angle corresponding to the equivalent wind speed of the impeller surface through the steady-state relationship curve; and calculate the feedforward pitch angle based on the steady-state pitch angle and the actual pitch angle.

[0075] The setting module is used to specify the reference speed of the fan.

[0076] The active disturbance rejection control module is connected to the acquisition module and the setting module. The active disturbance rejection control module is configured to obtain the active disturbance rejection control quantity based on the actual speed of the wind turbine rotor and the reference speed of the wind turbine.

[0077] The compensation module, connected to the feedforward control module and the active disturbance rejection control module, is used to compensate the active disturbance rejection control quantity using the steady-state pitch angle to obtain the pitch angle setpoint.

[0078] The pitch module, connected to the compensation module, is used to limit the speed and angle of the given pitch angle based on the actual operating conditions of the wind turbine, so as to obtain the final executed pitch angle.

[0079] In one embodiment, the feedforward control module includes:

[0080] The calculation submodule is connected to the acquisition module. The calculation submodule is configured to: calculate the equivalent wind speed of the impeller surface based on the wind speed information, obtain the steady-state pitch angle corresponding to the equivalent wind speed of the impeller surface through the steady-state relationship curve, and calculate the feedforward pitch angle based on the steady-state pitch angle and the actual pitch angle.

[0081] The fitting submodule is connected to the acquisition module and the calculation submodule. The fitting submodule is configured to: calculate the pitch angle corresponding to the wind speed based on the aerodynamic characteristics of the wind turbine and the wind speed information, and then fit the curve to obtain the steady-state relationship curve.

[0082] Compared with existing technologies, the anti-disturbance composite wind turbine pitch control method based on lidar in this application obtains the feedforward pitch angle based on lidar wind speed measurement information, and uses the feedforward pitch angle to compensate for the active disturbance rejection control quantity, so as to apply the wind speed information measured by lidar to the pitch control, enabling it to respond to wind speed changes in advance, thereby compensating for the hysteresis of existing feedback controllers, completing the function of dynamic feedforward compensation, and improving control accuracy.

[0083] This application presents an anti-disturbance composite wind turbine pitch control system based on lidar. By combining a feedforward control module and an active disturbance rejection control module, it addresses the problem of drastic changes in wind turbine power and rotor speed caused by factors such as random and sudden wind speed changes and control lag, thereby improving power generation quality.

[0084] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0085] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0086] Figure 1 This is a schematic flowchart of the anti-interference composite wind turbine pitch control method based on lidar provided in the embodiments of this application.

[0087] Figure 2 This is a schematic diagram of the method for calculating the equivalent wind speed on the impeller surface provided in the embodiments of this application.

[0088] Figure 3 This is a schematic diagram of the incoming flow detection for the cabin-type wind-measuring lidar provided in the embodiments of this application.

[0089] Figure 4 This is a schematic diagram of the incoming wind inversion method using two laser beams for wind measurement provided in this application embodiment.

[0090] Figure 5 This is a schematic diagram of wind speed time series provided in the embodiments of this application.

[0091] Figure 6 This is a schematic diagram of the equivalent wind speed of the impeller surface provided in the embodiments of this application.

[0092] Figure 7 This is a schematic diagram of the operation area division of variable speed wind power generation provided in the embodiments of this application.

[0093] Figure 8 This is a schematic diagram of the method for obtaining steady-state relationship curves provided in the embodiments of this application.

[0094] Figure 9 This is a schematic diagram of the steady-state relationship curve provided in the embodiments of this application.

[0095] Figure 10 This is a schematic flowchart of the method for calculating the pitch angle provided in the embodiments of this application.

[0096] Figure 11 This is a schematic diagram showing the partial derivative values ​​of torque with respect to wind turbine speed, blade pitch angle, and wind speed provided in the embodiments of this application.

[0097] Figure 12 This is an overall block diagram of the anti-interference composite wind turbine pitch control method based on lidar provided in the embodiments of this application.

[0098] Figure 13 This is a block diagram of the anti-interference composite wind turbine pitch control system based on lidar provided in the embodiments of this application.

[0099] Figure 14 This is a schematic diagram of the control effect under uniform wind speed of 16m / s provided in the embodiments of this application.

[0100] Figure 15 This is a diagram illustrating the control effect under random wind with an average wind speed of 16 m / s, provided in an embodiment of this application.

[0101] Figure 16 This is a schematic diagram comparing the wind speed at a lidar measurement point 100 meters away from the wind turbine surface with the actual wind speed, provided in an embodiment of this application.

[0102] In the figure, 1 is a lidar, 2 is a lidar-based anti-disturbance composite wind turbine pitch control system, 21 is an acquisition module, 22 is a feedforward control module, 221 is a calculation submodule, 222 is a fitting submodule, 23 is a setting module, 24 is an active disturbance rejection control module, 25 is a compensation module, and 26 is a pitch module. Detailed Implementation

[0103] The first aspect of this invention provides a method for anti-interference composite wind turbine pitch control based on lidar, such as... Figure 1 As shown, it includes:

[0104] S1. Obtain the actual rotational speed of the wind turbine rotor and the wind speed information measured by lidar, and calculate the equivalent wind speed on the impeller surface based on the wind speed information.

[0105] Laser wind-measuring radars are categorized into nacelle-mounted and ground-based laser radars based on their installation location. Ground-based laser radars are installed at predetermined locations within the wind farm, but they struggle to accurately measure the wind speed at the windward side of the rotor when the wind turbine is yawing. Nacelle-mounted laser radars, based on the optical coherent Doppler frequency shift detection principle, can achieve refined detection of the incoming wind field directly in front of the rotor hub. Compared to traditional wind measurement methods, nacelle-mounted Doppler laser radars offer advantages such as higher measurement accuracy, higher spatiotemporal resolution, and lower detection blind zones, and are now incorporated into the IEC international standard IEC61400-50-3:2022. In this embodiment, a nacelle-mounted wind-measuring laser radar emits four laser beams within a range of 30 to 600 meters in front of the wind turbine, emitting them in the direction of the incoming wind flow, to achieve precise detection of the atmospheric wind field. This provides crucial feedforward information for optimizing wind turbine pitch control and improving wind energy capture efficiency, enabling adaptive control based on laser radar wind field perception.

[0106] In one embodiment of this application, as Figure 2 As shown, the method for calculating the equivalent wind speed on the impeller surface is as follows:

[0107] S101. Obtain the radial wind speed of the four beams of the lidar at a set distance.

[0108] One possible approach, such as Figure 3 As shown, the lidar emitter employs a dual-plane, four-beam spatial scanning architecture. The horizontal subtended angles of the four laser beams (LOS1, LOS2, LOS3, LOS4) are... =15°, vertical angle is =7.5°, the beam is marked clockwise relative to the lidar. This allows us to obtain four laser beams at a set distance (e.g., radial wind speed at (meters) , , , .

[0109] S102. The combined wind speed of the upper beam and the combined wind speed of the lower beam are calculated based on the radial wind speed.

[0110] Specifically, the formula for calculating the combined wind speed of the upper beam is as follows:

[0111] ;

[0112] in, To synthesize the lateral component of the wind speed using the upper beam, For the longitudinal component of the wind speed synthesized by the upper beam, The horizontal subtended angles of the four beams, The vertical subtraction angles of the four beams, , The radial wind speed of the beam at a set distance. The wind speed is the composite wind speed of the upper beam.

[0113] Formula for calculating the combined wind speed of the lower beam:

[0114] ;

[0115] in, To synthesize the lateral component of the wind speed in the lower beam, For the longitudinal component of the wind speed synthesized by the lower beam, , The radial wind speed of the beam at a set distance. The wind speed is the composite wind speed of the lower beam.

[0116] One possible approach, such as Figure 4 As shown, this is a schematic diagram of wind speed and direction measured by two parallel laser beams looking down at lidar 1. and These represent the wind speeds measured by the two lidar beams. The incoming air velocity (i.e., the equivalent air velocity at the impeller surface) can be divided into a longitudinal component. and horizontal components After obtaining the equivalent wind speed on the impeller surface through geometric calculations using two parallel laser beams, this can be further extended to the case of four laser beams. The direction parallel to the incoming wind direction at the windward location of the fan is defined as the longitudinal direction, and the direction perpendicular to the incoming wind direction is defined as the transverse direction. The combined wind speed of the beams is then marked as... The combined wind speed of the lower beam is denoted as Equivalent wind speed on impeller surface for and The average value. The wind speeds of both the upper and lower beams can be decomposed into longitudinal components. and horizontal components .

[0117] S103. Calculate the average of the upper beam composite wind speed and the lower beam composite wind speed to obtain the equivalent wind speed on the impeller surface.

[0118] Specifically, the equivalent wind speed on the impeller surface is the weighted average or uniform average of the combined wind speed of the upper beam and the combined wind speed of the lower beam.

[0119] For example, the atmospheric wind field upwind of the wind turbine satisfies the assumption of local uniformity, with uniform, steady, and turbulent airflow. Wind speed data can be obtained from typical detection range points of the lidar installed in the nacelle, thus yielding secondary wind speed data and short-term average wind speed data for these detection range points. The IECKAI turbulence model in the TurbSim module of the OpenFAST software is used to generate average wind speed data of 17 m / s. Figure 5As shown, the wind speed curves at four measurement points are displayed. Using the radial wind speed measurements from the four laser beams on the radar measurement surface, the weighted average or uniform average of the combined wind speeds of the upper and lower beams is calculated to obtain the impeller's equivalent wind speed.

[0120] In one embodiment of this application, a certain buffer time is required when acquiring the wind speed signal to compensate for the operating characteristics of the pitch actuator. This is because the distance from the wind measurement center point to the wind turbine rotor is... The equivalent wind speed on the impeller surface is According to Taylor's frozen turbulence hypothesis, lidar can obtain wind information in front of the wind turbine rotor in advance, such as... Figure 6 As shown, the time it takes for the wind speed measured by lidar 1 to reach the impeller surface is: .time Much greater than the time constant of the pitch actuator Therefore, after the buffer period Then, processed wind speed information is acquired so that the blade movement can be synchronized with the wind reaching the rotor plane.

[0121] Buffer time The calculation formula is:

[0122] ;

[0123] in, This is the distance from the center point of the wind measurement to the fan rotor. The impeller surface equivalent wind speed, This is the filter delay time. For radar scanning delay time, This is the time constant of the pitch actuator.

[0124] S2. Based on the aerodynamic characteristics of the wind turbine and the wind speed information, calculate the pitch angle corresponding to the wind speed and fit it to obtain the steady-state relationship curve.

[0125] Based on the operating area division of variable speed wind power generation systems (i.e., wind turbines), the power control of variable speed wind power generation systems can be adjusted into four operating areas, such as... Figure 7 As shown, each region has different power control methods and objectives. The wind speed in region I is less than the cut-in wind speed. Region 1 is the startup phase of the wind power system; Region 2II is the maximum wind energy tracking operation area of ​​the wind power system, which is in the variable speed operation zone; Region 3III is the constant power zone of the wind power system, with a power output of [missing information]. Stable at rated power The wind speed in Zone III is at the rated wind speed. With cut-out wind speed Between; the wind speed in region IV is greater than the cut-out wind speed. The wind power system is in feathering mode and no longer operates. Therefore, pitch control mainly operates in Zone III.

[0126] In Region 3III, to ensure that the output power of the wind power generation system does not exceed the power limit and to avoid overload and overheating of the turbines, the turbine speed needs to decrease rapidly with increasing wind speed. The turbine output power can be controlled by changing the pitch angle, as the output power is affected by the wind energy utilization coefficient and wind speed. In this application's embodiment, the basic principle for the feedforward control design of variable pitch offshore wind turbines is to establish a steady-state relationship between the pitch angle and wind speed based on the turbine's aerodynamic characteristics. Then, using wind speed information measured by a laser wind-measuring radar (i.e., lidar), the equivalent wind speed at the rotor surface is calculated, yielding the steady-state pitch angle corresponding to the equivalent wind speed at the rotor surface, thus completing the feedforward control.

[0127] In one embodiment of this application, as Figure 8 As shown, the method for obtaining the steady-state relationship curve is as follows:

[0128] S201, Set the wind speed variation step size and rated power.

[0129] S202. Based on the wind speed variation step size and rated power, calculate the pitch angle of each wind speed within the wind speed range from rated wind speed to cut-out wind speed.

[0130] S203. Based on each wind speed and the corresponding blade pitch angle, the steady-state relationship curve is obtained through polynomial fitting.

[0131] For example, based on the aerodynamic characteristics of the wind turbine, the wind speed variation step size is set to 11.4 m / s, the rated power is set to 5.3 MW, and the process starts from the rated wind speed (at which point the pitch angle is adjusted). ), Calculations are performed according to the control objectives of the constant power operating region, continuing until the cutoff wind speed, resulting in a series of wind speed-pitch angle data pairs (i.e., each wind speed and its corresponding pitch angle). The steady-state relationship curve between wind speed and pitch angle is then obtained using a polynomial fitting method, such as Figure 9 As shown.

[0132] In one embodiment of this application, as Figure 10 As shown, the method for calculating the pitch angle is as follows:

[0133] S301. Substitute the wind speed and rated power into the OpenFAST wind turbine model to calculate the initial pitch angle and output power;

[0134] S302. The initial pitch angle is obtained by adjusting the pitch angle using the reference pitch PI controller;

[0135] S303. Determine whether the difference between the output power and the rated power is less than the first set value;

[0136] S304. When the difference between the output power and the rated power is greater than or equal to the first set value, continue to use the reference pitch PI controller to adjust the initial pitch angle to obtain the pitch angle.

[0137] S305. When the difference between the output power and the rated power is less than the first set value, the pitch angle is the pitch angle corresponding to the wind speed.

[0138] S306. Determine whether the wind speed change step size is equal to the second set value;

[0139] S307. When the wind speed change step size is not equal to the second set value, increase the wind speed change step size by one.

[0140] S308. Repeat steps S301 to S307 until the wind speed change step size equals the second set value.

[0141] S309. When the wind speed change step size is equal to the second set value, obtain each wind speed and the corresponding blade pitch angle.

[0142] For example, the first setting value and the second setting value are set according to the actual situation. For example, the second setting value can be set to 25m / s.

[0143] S3. Obtain the steady-state pitch angle corresponding to the equivalent wind speed on the impeller surface through the steady-state relationship curve, and calculate the feedforward pitch angle by combining it with the actual pitch angle.

[0144] The embodiments of this application can apply the wind speed information measured by lidar to variable pitch control, thereby compensating for the lag in feedback control, achieving the function of dynamic feedforward compensation, and improving control accuracy.

[0145] S4. Given the reference speed of the wind turbine, obtain the active disturbance rejection control quantity based on the actual speed of the wind turbine rotor and the reference speed of the wind turbine.

[0146] Compared to traditional PID controllers, Active Disturbance Rejection Control (ADRC) offers advantages such as smaller control overshoot, faster response, higher accuracy, and stronger anti-interference capabilities. Therefore, combining feedforward control from laser wind-measuring radar with ADRC strategies to address the complex issues of unknown wind speed disturbances, parameter variations, and multiple couplings in offshore wind power systems can improve power generation quality.

[0147] Specifically, a wind turbine drive model based on a wind turbine:

[0148] ;

[0149] In the formula, The equivalent moment of inertia of the wind turbine rotor. This refers to the aerodynamic torque of the fan. This refers to the generator torque of the wind turbine. This refers to the rotor speed of the fan impeller. The collective blade pitch angle of the wind turbine. For wind speed, For the gearbox speed ratio, , This refers to the rotor speed of the wind turbine's generator. This is the first derivative of the impeller rotor speed.

[0150] Taylor expansion of the aerodynamic torque at the steady-state operating point of the wind turbine yields the locally linearized result of the aerodynamic torque variation:

[0151] ;

[0152] in, , , , ;

[0153] In the formula, This is for aerodynamic torque error. The aerodynamic torque at the steady-state operating point of the fan. For impeller rotor speed error, The impeller rotor speed at the steady-state operating point of the fan. This is the error in the pitch angle. The pitch angle at the steady-state operating point of the wind turbine. To account for wind speed estimation error, The wind speed at the steady-state operating point of the fan. is a higher-order infinitesimal in the Taylor expansion. This is the partial derivative of the torque with respect to the impeller rotor speed at the steady-state operating point. This is the partial derivative of the torque with respect to the pitch angle at the steady-state operating point. Let be the partial derivative of torque with respect to wind speed at the steady-state operating point.

[0154] Utilizing the aerodynamic torque of the fan and the rotor speed of the impeller Pitch angle and wind speed The functional relationship between them was used to calculate the partial derivative of torque with respect to impeller rotor speed. The partial derivative of torque with respect to pitch angle and the partial derivative of torque with respect to wind speed This will further determine the current steady-state operating point of the wind turbine. , , Substituting the numerical values ​​into the partial derivatives above, we obtain the following results: , , .

[0155] For example, the partial derivative of torque with respect to impeller rotor speed is calculated using a linearization procedure. Partial derivative of torque with respect to pitch angle and the partial derivative of torque with respect to wind speed like Figure 11 As shown.

[0156] Based on the torque partial derivative value, combined with the formula , will Rewritten as:

[0157] ;

[0158] in, This is the second derivative of the impeller rotor speed error; , The time constant of the pitch system, This is a control value for the pitch angle; The total disturbance of the pitch system is expressed as:

[0159] ;

[0160] in, The derivative of the impeller rotor speed error. The derivative of the wind speed estimation error. The derivative of the generator torque error. This refers to the generator torque error. Let be the derivative of the higher-order terms of the Taylor expansion.

[0161] Specifically, based on the partial derivative values ​​of the torque, the equation can be... Written as:

[0162] .

[0163] Using the change in impeller rotor speed as the input to the controller (i.e., active disturbance rejection control), and combining with the above formula, we can obtain:

[0164] .

[0165] After Laplace transforming the above equation, we get:

[0166] ;

[0167] In the formula, considering the dynamic characteristics of the pitch angle, we have: ;

[0168] in, It is a complex variable.

[0169] The Laplace transform is a commonly used integral transform in applied mathematics, denoted by L[f(t)]. It is a linear transform that converts a function with real variables into a function with complex variables. The function.

[0170] Under the initial condition of 0, the above equation is obtained by performing an inverse Laplace transform:

[0171] .

[0172] Based on the principle of active disturbance rejection control, and using the gray box method for disturbance estimation, a state-space model of the total disturbance is obtained.

[0173] Specifically, based on the principle of active disturbance rejection control, three state variables are selected as follows: , , The state-space model of the total disturbance is obtained as follows:

[0174] ;

[0175] in, , , They are respectively , , The derivative, for The derivative;

[0176] Based on the disturbance estimation using the gray box method, the total disturbance of the pitch system is obtained. It can be represented as:

[0177] ;

[0178] In the formula:

[0179] ;

[0180] ;

[0181] in, For estimable terms, This is an unknown disturbance.

[0182] The linear extended state observer is designed based on the state-space model of the total disturbance as follows:

[0183] ;

[0184] in, , , For the state variables of a linearly extended state observer, for The derivative, for The derivative, for The derivative, This is the output of the state-space model of the total disturbance. , , The parameter to be adjusted;

[0185] Let the gain matrix be... Then it can be adjusted using the following formula:

[0186] ;

[0187] in, For complex variables, It is the identity matrix. The system matrix in the state-space model. For the output matrix, Let be the expected bandwidth of the linearly extended state observer.

[0188] Based on a linear extended state observer and using a linear state feedback controller, the expression for the active disturbance rejection control quantity is obtained:

[0189] ;

[0190] in, ;

[0191] In the formula, This is the active disturbance rejection control variable. For virtual control variables, This is the reference speed for the fan. , Let the controller gain matrix be the parameters of the controller to be designed. Then it satisfies ;

[0192] in, The state matrix, , For the input matrix, , The bandwidth of the controller to be designed.

[0193] S5. Use the feedforward pitch angle to compensate for the active disturbance rejection control quantity and obtain the pitch angle setpoint;

[0194] S6. Based on the actual operating conditions of the wind turbine, the given value of the pitch angle is subject to speed and angle limits to obtain the final executed pitch angle.

[0195] Specifically, when the wind speed increases, the control quantity becomes positive, the setpoint increases rapidly, and the execution pitch angle is increased in time to reduce wind energy capture and thus reduce power generation; conversely, when the wind speed decreases, the control quantity becomes negative, the setpoint decreases rapidly, and the power generation is increased in time to ensure stable and continuous grid-connected power transmission.

[0196] In one exemplary embodiment, such as Figure 12 As shown, the anti-interference composite wind turbine pitch control method based on lidar includes:

[0197] Obtain the actual rotational speed of the wind turbine rotor and the wind speed measured by lidar. ;

[0198] The equivalent wind speed on the impeller surface was calculated based on the wind speed information. ;

[0199] Based on the aerodynamic characteristics of the wind turbine and wind speed information, the pitch angle corresponding to the wind speed is calculated and fitted to obtain the steady-state relationship curve;

[0200] The steady-state pitch angle corresponding to the equivalent wind speed on the impeller surface is obtained from the steady-state relationship curve. and the actual pitch angle The feedforward pitch angle is obtained by addition and subtraction calculations. That is:

[0201] Feedforward pitch angle = -

[0202] Given a reference speed for the wind turbine, the actual speed of the wind turbine rotor is then used to determine the appropriate speed. With the reference speed of the fan An extended state observer (ESO) is used to obtain a linear extended state observer (LESO), and the active disturbance rejection control quantity is calculated using a linear state feedback control law (LSEF). ;

[0203] The feedforward pitch angle output by the feedforward controller is used to determine the active disturbance rejection control quantity output by the ARDR controller (i.e., the active disturbance rejection controller). Compensation is performed to obtain the given pitch angle value. ;

[0204] Based on the actual operating conditions of the wind turbine, the pitch mechanism limits the speed (i.e., speed restriction) and restricts the position (i.e., angle restriction) of the given pitch angle to obtain the final executed pitch angle. .

[0205] A second aspect of the present invention provides an anti-interference composite wind turbine pitch control system based on lidar, such as... Figure 13 As shown, the anti-interference composite wind turbine pitch control system 2 based on lidar includes:

[0206] The acquisition module 21 is used to acquire wind speed information measured by lidar and to acquire the actual rotational speed of the wind turbine rotor;

[0207] The feedforward control module 22, connected to the acquisition module 21, is configured to: calculate the equivalent wind speed of the impeller surface based on the wind speed information; calculate the pitch angle corresponding to the wind speed based on the aerodynamic characteristics of the fan and the wind speed information, and fit it to obtain a steady-state relationship curve; obtain the steady-state pitch angle corresponding to the equivalent wind speed of the impeller surface through the steady-state relationship curve; and calculate the feedforward pitch angle based on the steady-state pitch angle and the actual pitch angle.

[0208] Setting module 23 is used to provide a reference speed for the fan;

[0209] The active disturbance rejection control module 24 is connected to the acquisition module 21 and the setting module 23. The active disturbance rejection control module 24 is configured to obtain the active disturbance rejection control quantity based on the actual speed of the wind turbine rotor and the reference speed of the wind turbine.

[0210] The compensation module 25 is connected to the feedforward control module 22 and the active disturbance rejection control module 24, and is used to compensate the active disturbance rejection control quantity using the steady-state pitch angle to obtain the pitch angle setpoint.

[0211] The pitch module 26, connected to the compensation module 25, is used to limit the speed and angle of the given pitch angle according to the actual operating conditions of the wind turbine, so as to obtain the final execution pitch angle.

[0212] In one embodiment, see further. Figure 13 The feedforward control module 22 includes:

[0213] The calculation submodule 221 is connected to the acquisition module 21. The calculation submodule 221 is configured to: calculate the equivalent wind speed of the impeller surface based on the wind speed information, obtain the steady-state pitch angle corresponding to the equivalent wind speed of the impeller surface through the steady-state relationship curve, and calculate the feedforward pitch angle based on the steady-state pitch angle and the actual pitch angle.

[0214] The fitting submodule 222 is connected to the acquisition module 21 and the calculation submodule 221. The fitting submodule 222 is configured to: calculate the pitch angle corresponding to the wind speed based on the aerodynamic characteristics of the wind turbine and the wind speed information, and fit the steady-state relationship curve.

[0215] To verify the correctness and effectiveness of the feedforward control method in this study, a joint simulation experiment was conducted using the professional simulation software Matlab / Simulink to build a controller and a 5MW wind turbine generator model provided by OpenFAST. The speed limit of the pitch angle actuator was -8 to +8° / s, and the angle position limit was 0 to 90°. Other simulation model parameter settings are shown in Table 1.

[0216] Table 1 Simulation Model Parameters

[0217]

[0218] In the ADRC algorithm, the control quantity coefficient Set to 1, ESO bandwidth The accuracy of the estimated value is related to the performance of ESO; the larger the value, the better the observation performance of LSET. This is related to the system's response speed; the larger the value, the faster the controller. (The text then lists several values, which are not translated as they are not part of the main text.) , .

[0219] Comparative experiments were conducted between the feedforward ADRC (i.e., this application) and a PI controller and a feedforward PI controller, respectively. The LiDAR (Light Detection and Ranging) system transmitted the processed equivalent wind speed information of the impeller surface to the feedforward controller. The operating effect under uniform wind speed conditions is as follows: Figure 14 As shown, the embodiments of this application can be seen to adjust the pitch in advance based on radar wind measurement information and reduce the impact of wind speed changes on the wind turbine rotation speed.

[0220] Simulation operation under random wind speed conditions, such as Figure 15 As shown in the figure, the comparison of pitch angle and rotor speed reveals that the control performance of the feedforward ADRC and feedforward PI controllers is not significantly different. The feedforward ADRC employs a more aggressive pitch control strategy, resulting in better rotor speed control compared to the feedforward PI controller. Furthermore, the generated power is more stable after adopting the feedforward ADRC.

[0221] Table 2 shows the comparison results of the standard deviation of rotor speed, pitch angle and power generation under different control schemes.

[0222] Table 2 Comparison of standard deviations of rotor speed, pitch angle, and power generation under different control schemes.

[0223]

[0224] Using the lidar measurement function of the InFlowWind module in OpenFAST, the wind speed at a certain distance in the windward direction of the wind turbine can be measured. Figure 16 This is a comparison chart of the wind speed at a measurement point 100 meters away from the wind turbine surface and the actual wind speed.

[0225] from Figure 16As can be clearly seen from Table 2, compared with traditional PI control, the introduction of a feedforward controller reduces the system's settling time and overshoot. This indicates that the feedforward controller proposed in this embodiment provides better control performance for systems with continuous wind speed disturbances. After the feedback controller of the wind turbine generator was changed from the original PI controller to an ADRC controller, the control action of the pitch angle became more aggressive, thus significantly improving the stability of the rotor speed and power. From the comparison results of the pitch angle standard deviation in Table 2, it can be seen that compared with the PI control method, the standard deviation of the pitch angle under ADRC control increased slightly by 1%, but this significantly reduced the standard deviations of rotor speed and power generation by 16% and 23%, respectively.

[0226] In summary, compared with the reference gain-scheduled PI controller, the proposed feedforward ADRC controller exhibits less overshoot and a faster response time, thus achieving better dynamic performance. Therefore, the control effect of the feedforward ADRC controller is superior to that of the gain-scheduled PI controller.

Claims

1. A method for anti-interference composite wind turbine pitch control based on lidar, characterized in that, include: The actual rotational speed of the wind turbine rotor and the wind speed information measured by lidar are obtained, and the equivalent wind speed on the impeller surface is calculated based on the wind speed information. Based on the aerodynamic characteristics of the wind turbine and wind speed information, the pitch angle corresponding to the wind speed is calculated and fitted to obtain the steady-state relationship curve; The steady-state pitch angle corresponding to the equivalent wind speed on the impeller surface is obtained by the steady-state relationship curve, and the feedforward pitch angle is calculated based on the steady-state pitch angle and the actual pitch angle. Given the reference speed of the wind turbine, the active disturbance rejection control quantity is obtained based on the actual speed of the wind turbine rotor and the reference speed of the wind turbine. The feedforward pitch angle is used to compensate for the active disturbance rejection control variable, and the pitch angle setpoint is obtained. Based on the actual operating conditions of the wind turbine, the speed and angle limits are applied to the given value of the pitch angle to obtain the final executed pitch angle; The method for obtaining the active disturbance rejection control quantity is as follows: Wind turbine-based rotor drive model: ； In the formula, The equivalent moment of inertia of the wind turbine rotor. This refers to the aerodynamic torque of the fan. This refers to the generator torque of the wind turbine. This refers to the rotor speed of the fan impeller. The collective blade pitch angle of the wind turbine. For wind speed, For the gearbox speed ratio, , This refers to the rotor speed of the wind turbine's generator. This is the first derivative of the impeller rotor speed; Taylor expansion of the aerodynamic torque at the steady-state operating point of the wind turbine yields the locally linearized result of the aerodynamic torque variation: ； in, , , , ; In the formula, This is for aerodynamic torque error. The aerodynamic torque at the steady-state operating point of the fan. For impeller rotor speed error, The impeller rotor speed at the steady-state operating point of the fan. This is the error in the pitch angle. The pitch angle at the steady-state operating point of the wind turbine. To account for wind speed estimation error, The wind speed at the steady-state operating point of the fan. is a higher-order infinitesimal in the Taylor expansion. Let be the partial derivative of torque with respect to impeller rotor speed. This is the partial derivative of the torque with respect to the pitch angle. This is the partial derivative of torque with respect to wind speed; make , , Based on the partial derivative values ​​of the torque, combined with the formula , will Rewritten as: ； in, This is the second derivative of the impeller rotor speed error; , The time constant of the pitch system, This is a control value for the pitch angle; The total disturbance of the pitch system is expressed as: ； in, The derivative of the impeller rotor speed error. The derivative of the wind speed estimation error. The derivative of the generator torque error. This refers to the generator torque error. is the derivative of the higher-order terms in the Taylor expansion; Based on the principle of active disturbance rejection control, and using the disturbance estimation based on the gray box method, a state-space model of the total disturbance is obtained. The linear extended state observer is designed based on the state-space model of the total disturbance as follows: ； in, , , For the state variables of a linearly extended state observer, for The derivative, for The derivative, for The derivative, This is the output of the state-space model of the total disturbance. , , The parameter to be adjusted; Let the gain matrix be... Then it can be adjusted using the following formula: ； in, For complex variables, It is the identity matrix. The system matrix in the state-space model. For the output matrix, The expected bandwidth of the linearly extended state observer; Based on a linear extended state observer and using a linear state feedback controller, the expression for the active disturbance rejection control quantity is obtained: ； in, This is the active disturbance rejection control variable. ; In the formula, For virtual control variables, This is the reference speed for the fan. , Let the controller gain matrix be the parameters of the controller to be designed. Then it satisfies ; in, The state matrix, , For the input matrix, , The bandwidth of the controller to be designed.

2. The method according to claim 1, characterized in that, The method for calculating the equivalent wind speed on the impeller surface is as follows: Obtain the radial wind speed of the four beams of the lidar at a set distance; The combined wind speed of the upper beam and the combined wind speed of the lower beam are calculated based on the radial wind speed. The equivalent wind speed on the impeller surface is obtained by calculating the average of the combined wind speed of the upper and lower beams.

3. The method according to claim 2, characterized in that, The formula for calculating the combined wind speed of the upper beam is as follows: ； in, To synthesize the lateral component of the wind speed using the upper beam, For the longitudinal component of wind speed synthesized by the upper beam, The horizontal subtended angles of the four beams, The vertical subtraction angles of the four beams, , The radial wind speed of the beam at a set distance. The wind speed is the composite wind speed of the upper beam.

4. The method according to claim 3, characterized in that, The formula for calculating the combined wind speed of the lower beam is as follows: ； in, The lower beam synthesizes the lateral component of the wind speed. For the longitudinal component of the wind speed synthesized by the lower beam, , The radial wind speed of the beam at a set distance. The wind speed is the composite wind speed of the lower beam.

5. The method according to claim 1, characterized in that, The method for obtaining the steady-state relationship curve is as follows: Set the wind speed variation step size and rated power; Based on the wind speed variation step size and rated power, calculate the pitch angle of each wind speed within the wind speed range from rated wind speed to cut-out wind speed. Steady-state relationship curves are obtained by polynomial fitting based on each wind speed and the corresponding blade pitch angle.

6. The method according to claim 5, characterized in that, The method for calculating the pitch angle is as follows: The initial pitch angle and output power are calculated by substituting the wind speed and rated power into the OpenFAST wind turbine model; The initial pitch angle is obtained by adjusting the reference pitch PI controller; Determine whether the difference between the output power and the rated power is less than the first set value; When the difference between the output power and the rated power is greater than or equal to the first set value, the initial pitch angle is adjusted using the reference pitch PI controller to obtain the pitch angle. When the difference between the output power and the rated power is less than the first set value, the pitch angle is the pitch angle corresponding to the wind speed. Determine whether the wind speed change step size is equal to the second set value; When the wind speed change step size is not equal to the second set value, the wind speed change step size is increased by one. Repeat the above steps until the wind speed change step size equals the second set value; When the wind speed change step size is equal to the second set value, the pitch angle of each wind speed is obtained.

7. The method according to claim 1, characterized in that, The method for obtaining the state-space model of the total disturbance is as follows: Based on the principle of active disturbance rejection control, three state variables are selected as follows: , , The state-space model of the total disturbance is obtained as follows: ； in, , , They are respectively , , The derivative, for The derivative; Based on the disturbance estimation using the gray box method, the total disturbance of the pitch system is obtained. It can be represented as: ； In the formula: ； ； in, For estimable terms, This is an unknown disturbance.

8. A disturbance-resistant composite wind turbine pitch control system based on lidar, characterized in that, include: The acquisition module is used to acquire wind speed information measured by lidar and to acquire the actual rotational speed of the wind turbine rotor; The feedforward control module, connected to the acquisition module, is configured to: calculate the equivalent wind speed of the impeller surface based on the wind speed information; calculate the pitch angle corresponding to the wind speed based on the aerodynamic characteristics of the fan and the wind speed information, and fit it to obtain a steady-state relationship curve; obtain the steady-state pitch angle corresponding to the equivalent wind speed of the impeller surface through the steady-state relationship curve; and calculate the feedforward pitch angle based on the steady-state pitch angle and the actual pitch angle. The setting module is used to specify the reference speed of the fan. An active disturbance rejection control module is connected to the acquisition module and the setting module. The active disturbance rejection control module is configured to: obtain an active disturbance rejection control quantity based on the actual rotational speed of the wind turbine rotor and the reference rotational speed of the wind turbine; the method for obtaining the active disturbance rejection control quantity is as follows: Wind turbine-based rotor drive model: ； In the formula, The equivalent moment of inertia of the wind turbine rotor. This refers to the aerodynamic torque of the fan. This refers to the generator torque of the wind turbine. This refers to the rotor speed of the fan impeller. The collective blade pitch angle of the wind turbine. For wind speed, For the gearbox speed ratio, , This refers to the rotor speed of the wind turbine's generator. This is the first derivative of the impeller rotor speed; Taylor expansion of the aerodynamic torque at the steady-state operating point of the wind turbine yields the locally linearized result of the aerodynamic torque variation: ； in, , , , ; In the formula, This is for aerodynamic torque error. The aerodynamic torque at the steady-state operating point of the fan. For impeller rotor speed error, The impeller rotor speed at the steady-state operating point of the fan. This is the error in the pitch angle. The pitch angle at the steady-state operating point of the wind turbine. To account for wind speed estimation error, The wind speed at the steady-state operating point of the fan. is a higher-order infinitesimal in the Taylor expansion. Let be the partial derivative of torque with respect to impeller rotor speed. This is the partial derivative of the torque with respect to the pitch angle. This is the partial derivative of torque with respect to wind speed; make , , Based on the partial derivative values ​​of the torque, combined with the formula , will Rewritten as: ； in, This is the second derivative of the impeller rotor speed error; , The time constant of the pitch system, This is a control value for the pitch angle; The total disturbance of the pitch system is expressed as: ； in, The derivative of the impeller rotor speed error. The derivative of the wind speed estimation error. The derivative of the generator torque error. This refers to the generator torque error. is the derivative of the higher-order terms in the Taylor expansion; Based on the principle of active disturbance rejection control, and using the disturbance estimation based on the gray box method, a state-space model of the total disturbance is obtained. The linear extended state observer is designed based on the state-space model of the total disturbance as follows: ； in, , , For the state variables of a linearly extended state observer, for The derivative, for The derivative, for The derivative, This is the output of the state-space model of the total disturbance. , , The parameter to be adjusted; Let the gain matrix be... Then it can be adjusted using the following formula: ； in, For complex variables, It is the identity matrix. The system matrix in the state-space model. For the output matrix, The expected bandwidth of the linearly extended state observer; Based on a linear extended state observer and using a linear state feedback controller, the expression for the active disturbance rejection control quantity is obtained: ； in, This is the active disturbance rejection control variable. ; In the formula, For virtual control variables, This is the reference speed for the fan. , Let the controller gain matrix be the parameters of the controller to be designed. Then it satisfies ; in, The state matrix, , For the input matrix, , The bandwidth of the controller to be designed; The compensation module, connected to the feedforward control module and the active disturbance rejection control module, is used to compensate the active disturbance rejection control quantity using the steady-state pitch angle to obtain the pitch angle setpoint. The pitch module, connected to the compensation module, is used to limit the speed and angle of the given pitch angle based on the actual operating conditions of the wind turbine, so as to obtain the final executed pitch angle.

9. The system according to claim 8, characterized in that, The feedforward control module includes: The calculation submodule is connected to the acquisition module. The calculation submodule is configured to: calculate the equivalent wind speed of the impeller surface based on the wind speed information, obtain the steady-state pitch angle corresponding to the equivalent wind speed of the impeller surface through the steady-state relationship curve, and calculate the feedforward pitch angle based on the steady-state pitch angle and the actual pitch angle. The fitting submodule is connected to the acquisition module and the calculation submodule. The fitting submodule is configured to: calculate the pitch angle corresponding to the wind speed based on the aerodynamic characteristics of the wind turbine and the wind speed information, and then fit the curve to obtain the steady-state relationship curve.

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