A wind turbine independent pitch control method and system

Abstract

The application discloses a wind turbine independent variable pitch control method and system, the method comprises the following steps: S1, collecting the four direction shaking posture angle data of the wind turbine; S2, calculating the axial thrust and lateral thrust of the wind turbine according to the collected data; S3, calculating the variable pitch instruction in three-phase coordinates according to the axial thrust and lateral thrust of the wind turbine, superimposing the variable pitch instruction in the three-phase coordinate system into the unified variable pitch demand instruction, and delivering the unified variable pitch demand instruction to the variable pitch actuator; S4, the variable pitch actuator controls the variable pitch action of the wind turbine based on the unified variable pitch demand instruction; the application can reflect the dynamic change of the axial thrust and lateral thrust of the wind turbine in real time, reduce the limit and fatigue load caused by the thrust fluctuation in a targeted manner, and dynamically adjust the variable pitch instruction according to the turbulence of the actual wind field, so that the damage to the variable pitch bearing and the component limit load caused by the thrust fluctuation and imbalance can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind turbine variable pitch control, in particular to a wind turbine independent variable pitch control method and system. BACKGROUND

[0002] With the trend of wind turbine towards larger capacity and larger blades, the extreme and fatigue loads of wind turbine will significantly increase in the areas with relatively poor wind resources.

[0003] In the large shear environment, the wind speed distribution of the wind wheel surface is too large, which leads to significant unbalanced load of the unit, and significantly increases the extreme load of each key component of the unit. In the large turbulence environment, the response delay caused by the moment of inertia and torque of the wind wheel and the variable pitch control will significantly increase the fatigue load of each component of the unit. Therefore, how to reduce the extreme and fatigue load of the unit under extreme wind conditions has become a technical problem to be solved in the field.

[0004] In the existing technical solutions, the independent variable pitch control of the wind turbine is mainly realized by the blade root, tower and main shaft load sensors to reduce the unbalanced load problem caused by wind shear or gravity factors. For example, in the invention patent application CN108035848A, a method for realizing independent variable pitch based on tower load sensor is disclosed, which realizes the independent variable pitch control of the wind turbine by installing load sensors on the top of the tower and through load coordinate system conversion and feedback control link.

[0005] In the existing technical solutions, the load data of different components are measured, and the variable pitch demand of each blade is calculated through coordinate system conversion, and then the independent variable pitch control of the wind turbine is realized.

[0006] However, the existing independent variable pitch control method has the following problems:

[0007] 1) The load measured by the load measuring device is mainly the bending moment generated by the aerodynamic thrust, centrifugal force and periodic gravity acting on the wind wheel surface. The existing independent variable pitch control method mainly solves the problem of aerodynamic and gravity unbalanced load, and it cannot directly reflect the thrust fluctuation level acting on the wind wheel surface. Therefore, the existing technical solutions cannot directly solve the tower fatigue and extreme load problem caused by too large thrust fluctuation under large turbulence working condition.

[0008] 2) The frequent and continuous variable pitch instruction of the existing technical means will increase the fatigue of the unit variable pitch bearing, and then affect the service life of the component. SUMMARY

[0009] The purpose of the present application is to overcome the deficiencies of the prior art, and provide a wind turbine independent variable pitch control method and system, which directly calculates the axial and lateral thrust of the wind turbine through the installed sensor, dynamically adjusts the variable pitch instruction according to the thrust fluctuation level, and can specifically solve the tower fatigue load problem caused by thrust fluctuation and reduce the variable pitch bearing damage problem.

[0010] The purpose of the present application is achieved by the following technical scheme: a wind turbine independent variable pitch control method, comprising the following steps:

[0011] S1, collecting four-direction shaking posture angle data of the wind turbine;

[0012] S2, calculating the axial thrust and lateral thrust of the wind turbine according to the collected data;

[0013] S3, calculating the variable pitch instruction in three-phase coordinates according to the axial thrust and lateral thrust of the wind turbine, superimposing the variable pitch instruction in the three-phase coordinate system into the unified variable pitch demand instruction, and transmitting to the variable pitch actuator;

[0014] S4, the variable pitch actuator controls the variable pitch action of the wind turbine based on the unified variable pitch demand instruction.

[0015] Further, the step S1 comprises:

[0016] A dynamic inclination sensor is installed at the nacelle of the wind turbine to obtain the front-to-back and left-to-right shaking posture angle data of the wind turbine.

[0017] Further, the step S2 comprises:

[0018] The axial and lateral thrust of the wind turbine is calculated based on the shaking posture angle of the nacelle;

[0019] The axial thrust calculation formula is:

[0020]

[0021] In the above formula, m t is the unit mass, d t is the damping, and s t is the stiffness matrix; δx fa is the filtered nacelle front-to-back shaking posture angle, is the nacelle front-to-back shaking posture angular velocity, is the nacelle front-to-back shaking posture angular acceleration, F ax is the axial thrust, M YB is the Y-direction rotation bending moment;

[0022] The lateral thrust calculation formula is:

[0023] The lateral thrust calculation formula is:

[0024] m in the above formula t is the mass of the unit, d t is the damping and s t is the stiffness matrix; δx ss is the filtered cabin roll attitude angle, δx is the filtered cabin roll attitude angular velocity, δx is the filtered cabin roll attitude angular acceleration, F ay is the lateral thrust, M ZB is the bending moment about the Z direction;

[0025] The filtered cabin pitch attitude angle and the filtered cabin roll attitude angle are calculated according to the following formulas:

[0026] δx fa = F(s) · δx x ;

[0027] δx ss = F(s) · δx y ;

[0028] In the above formula, F(s) is a low-pass and band-stop filter, δx x is the pitch angle, and δx y is the roll angle.

[0029] Further, the step S3 comprises:

[0030] Setting the axial thrust bias value and the lateral thrust bias value, and taking the axial thrust and the axial thrust bias value and the lateral thrust and the lateral thrust bias value as inputs of the feedback controller;

[0031] Defining the axial thrust deviation Δe x as the difference between the real-time axial thrust and the axial thrust bias;

[0032] Defining the lateral thrust deviation Δe y as the difference between the real-time lateral thrust and the lateral thrust bias;

[0033] Performing coordinate system transformation on the axial and lateral pitch angles β d and β q calculated by the feedback controller, i.e., converting the two-phase stationary coordinate system into a three-phase rotating coordinate system;

[0034] The feedback controller is calculated according to the following formula:

[0035]

[0036] In the above formula, k p is a proportional coefficient, k I is an integral coefficient, and kd is the differential coefficient, Δe x (j) is the current moment axial thrust error, Δe y (j) is the current moment lateral thrust error, Δe ax (n) is the rate of change of the axial thrust error, Δe ay (n) is the rate of change of the lateral thrust error;

[0037] To prevent the control system from being unstable or the fluctuation amplitude being too large, the calculated pitch command β d and β q are subjected to amplitude limiting processing;

[0038] The coordinate system conversion formula is as follows:

[0039]

[0040] In the above formula, θ is the blade azimuth angle, and δ is the phase delay offset;

[0041] The calculated pitch command in the three-phase coordinate system is superimposed on the unified pitch demand command, and finally transmitted to the pitch actuator.

[0042] Further, the step S3 comprises:

[0043] Based on the axial thrust and the lateral thrust, further calculate the bending moments in the front and back and left and right directions of the tower bottom of the wind turbine generator;

[0044] The relationship between the thrust and the bending moment is:

[0045] M y = F ax · h;

[0046] M x = F ay · h;

[0047] In the formula, M y , M x are the left and right and front and back bending moments respectively, and h is the tower height;

[0048] Set the front and back load bias value and the left and right load bias value, and take the calculated front and back bending moment and the front and back load bias value and the left and right bending moment and the left and right load bias value as the input of the feedback controller;

[0049] Define the front and back deviation Δe Mx as the difference between the real-time front and back bending moment and the front and back load bias value;

[0050] Define the left and right deviation Δe My as the difference between the real-time left and right bending moment and the left and right load bias value;

[0051] The feedback controller calculates the pitch angle β d and β q The coordinate system conversion is performed, i.e., the two-phase static coordinate system is converted into the three-phase rotating coordinate system.

[0052] The feedback controller formula is as follows:

[0053]

[0054] In the above formula, k p is a proportional coefficient, k I is an integral coefficient, and k d is a differential coefficient, Δe Mx (j) is the front-rear bending moment error at the current moment, Δe My (j) is the left-right bending moment error at the current moment, Δe aMx (n) is the front-rear bending moment error change rate, and Δe aMy (n) is the left-right bending moment error change rate.

[0055] The control system is prevented from being unstable or having an excessively large fluctuation amplitude, and the calculated pitch instruction β d and β q are subjected to amplitude limiting processing.

[0056] The coordinate system conversion formula is as follows:

[0057]

[0058] In the above formula, θ is the blade azimuth angle, and δ is the phase delay.

[0059] The calculated pitch instruction in the three-phase coordinate system is superimposed on the unified pitch demand instruction, and finally transmitted to the pitch actuator.

[0060] A wind turbine independent pitch control system for implementing the above wind turbine independent pitch control method, comprising:

[0061] A sway posture monitoring module for measuring the sway posture angle of the wind turbine nacelle and transmitting the measurement data to the data acquisition module through a transmission module;

[0062] A data acquisition module for acquiring sway posture angle data and transmitting the acquired data to the controller module through a transmission module;

[0063] A controller module for calculating the nacelle axial thrust and lateral thrust according to the data obtained through transmission, transmitting the calculated pitch instruction to the pitch actuator through a feedback controller and coordinate system conversion;

[0064] A transmission module for communication and data transmission between modules.

[0065] The pitch actuator controls the pitch of the wind turbine according to the pitch instruction.

[0066] Furthermore, the controller module performs the following operations:

[0067] Calculate the axial and lateral thrust of the wind turbine based on the swaying attitude angle of the nacelle;

[0068] The axial thrust calculation formula is:

[0069]

[0070] In the above formula, m t is the unit mass, d t is the damping and s t is the stiffness matrix; δx fa To filter the cabin's forward and backward shaking attitude angle, is the angular velocity of the cabin's forward and backward shaking attitude, F is the angular acceleration of the cabin's forward and backward shaking attitude, ax is the axial thrust, M YB is the rotational bending moment around the Y direction;

[0071] The lateral thrust calculation formula is:

[0072]

[0073] In the above formula, m t is the mass of the unit, d t is the damping and s t is the stiffness matrix; δx ss To filter the left and right shaking attitude angle of the cabin, is the angular velocity of the cabin's left and right shaking attitude, F is the angular acceleration of the cabin's left and right shaking attitude, ay is the axial thrust, M ZB is the rotational bending moment around the Z direction;

[0074] The calculation formulas for the front and rear swaying attitude angle of the filter cabin and the left and right swaying attitude angle of the filter cabin are as follows:

[0075] δx fa =F(s)·δx x ;

[0076] δx ss =F(s)·δx y ;

[0077] In the above formula, F(s) is a low-pass and band-stop filter, δx x is the forward and backward shaking angle, δx y is the left and right shaking angle;

[0078] The axial thrust bias value and the lateral thrust bias value are set, and the axial thrust and the axial thrust bias value, the lateral thrust and the lateral thrust bias value are taken as the input of the feedback controller;

[0079] The axial thrust error Δe x is defined as the difference between the real-time axial thrust and the axial thrust bias;

[0080] The lateral thrust error Δe y is defined as the difference between the real-time lateral thrust and the lateral thrust bias;

[0081] The axial and lateral pitch angles β d and β q calculated by the feedback controller are subjected to coordinate system transformation, i.e., conversion from two-phase stationary coordinate system to three-phase rotating coordinate system;

[0082] The feedback controller formula is as follows:

[0083]

[0084] In the above formula, k p is a proportional coefficient, k I is an integral coefficient, and k d is a differential coefficient, Δe x (j) is the axial thrust error at the current moment, Δe y (j) is the lateral thrust error at the current moment, Δe ax (n) is the axial thrust error change rate, and Δe ay (n) is the lateral thrust error change rate;

[0085] To prevent the control system from being unstable or having too large fluctuation amplitude, the calculated pitch commands β d and β q are subjected to amplitude limiting processing;

[0086] The coordinate system conversion formula is as follows:

[0087]

[0088] In the above formula, θ is the impeller azimuth angle, and δ is the phase delay offset;

[0089] The calculated pitch commands in the three-phase coordinate system are superimposed to the unified pitch demand command, and finally transmitted to the pitch actuator.

[0090] Further, the controller module performs the following operations:

[0091] Based on the axial thrust and the lateral thrust, the front and rear and left and right direction bending moments of the wind turbine tower bottom are further calculated;

[0092] The relationship between the thrust and the bending moment is:

[0093] M y = F ax · h;

[0094] M x = F ay · h;

[0095] In the formula, M y , M x are left and right and front and back bending moments, and h is the tower height;

[0096] The front and back load bias value and the left and right load bias value at the tower bottom are set, and the calculated front and back bending moment and the front and back load bias value and the left and right bending moment and the left and right load bias value are taken as inputs of the feedback controller;

[0097] The front and back deviation Δe Mx at the tower bottom is defined as the difference between the real-time front and back bending moment and the front and back load bias value at the tower bottom;

[0098] The left and right deviation Δe My at the tower bottom is defined as the difference between the real-time left and right bending moment and the left and right load bias value at the tower bottom;

[0099] The pitch angles β d and β q in the front and back and left and right directions calculated by the feedback controller are subjected to coordinate system transformation, i.e., conversion from two-phase static coordinate system to three-phase rotating coordinate system;

[0100] The formula of the feedback controller is as follows:

[0101]

[0102] In the above formula, k p is a proportional coefficient, k I is an integral coefficient, k d is a differential coefficient, Δe Mx (j) is the front and back bending moment error at the current moment, Δe My (j) is the left and right bending moment error at the current moment, Δe aMx (n) is the front and back bending moment error change rate, and Δe aMy (n) is the left and right bending moment error change rate.

[0103] To prevent the control system from being unstable or having too large fluctuation amplitude, the calculated pitch instructions β d and β q are subjected to amplitude limiting processing;

[0104] The coordinate system conversion formula is as follows:

[0105]

[0106] In the above formula, theta is the blade azimuth angle, and delta is the phase delay.

[0107] The calculated variable pitch instruction in the three-phase coordinate system is superimposed on the unified variable pitch demand instruction, and finally transmitted to the variable pitch actuator.

[0108] A non-transitory computer readable medium storing instructions, when executed by a processor, performs the steps of the wind turbine independent variable pitch control method.

[0109] A computing device comprising a processor and a memory for storing processor-executable programs, when the processor executes the programs stored in the memory, the wind turbine independent variable pitch control method is implemented.

[0110] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0111] 1. The present application can reflect the dynamic changes of the axial and lateral thrust of the unit in real time based on the inclination sensor;

[0112] 2. The independent variable pitch control method based on thrust designed in the present application can specifically reduce the limit and fatigue load problems caused by thrust fluctuation;

[0113] 3. The independent variable pitch control method based on thrust designed in the present application can dynamically adjust the variable pitch instruction according to the actual wind field turbulence, and can effectively reduce the damage to the variable pitch bearing;

[0114] 4. The independent variable pitch control method based on thrust designed in the present application can effectively reduce the component limit load problem caused by thrust fluctuation and imbalance. BRIEF DESCRIPTION OF DRAWINGS

[0115] Figure 1 The blade bending moment diagram of the wind turbine.

[0116] Figure 2 The independent variable pitch control principle diagram based on thrust.

[0117] Figure 3 The independent variable pitch control principle diagram based on tower bottom bending moment. DETAILED DESCRIPTION

[0118] The present application will be further described below in conjunction with specific embodiments.

[0119] Embodiment 1

[0120] The wind turbine independent variable pitch control method provided in the present embodiment comprises the following steps:

[0121] S1, collecting the four direction swing posture angle data of the wind turbine, installing a dynamic inclination sensor at the nacelle of the wind turbine to obtain the front and back direction and left and right direction swing posture angle data of the wind turbine;

[0122] S2, calculating the axial thrust and lateral thrust of the wind turbine according to the collected data, comprising:

[0123] calculating the axial and lateral thrust of the wind turbine based on the swing posture angle of the nacelle;

[0124] The axial thrust calculation formula is:

[0125]

[0126] In the above formula, m t is the mass of the unit, d t is the damping, and s t is the stiffness matrix; δx fa is the filtered nacelle front and back swing posture angle, is the nacelle front and back swing posture angular velocity, is the nacelle front and back swing posture angular acceleration, F ax is the axial thrust, M YB is the bending moment around the Y direction rotation;

[0127] Referring to Figure 1 , which is a wind turbine blade bending moment direction diagram, and therefore the lateral thrust calculation formula is:

[0128]

[0129] In the above formula, m t is the mass of the unit, d t is the damping, and s t is the stiffness matrix; δx ss is the filtered nacelle left and right swing posture angle, is the nacelle left and right swing posture angular velocity, is the nacelle left and right swing posture angular acceleration, F ay is the lateral thrust, M ZB is the bending moment around the Z direction rotation;

[0130] The filtered nacelle front and back swing posture angle and the filtered nacelle left and right swing posture angle calculation formula is as follows:

[0131] δx fa = F(s)·δx x ;

[0132] δx ss = F(s)·δx y ;

[0133] F(s) is a low-pass and band-stop filter in the above formula, δx x is the fore-aft sway angle, δx y is the side-to-side sway angle.

[0134] S3, according to the axial thrust and lateral thrust of the wind turbine, calculate the variable pitch command in three-phase coordinates, superimpose the variable pitch command in the three-phase coordinate system to the unified variable pitch demand command, and deliver it to the variable pitch actuator, including:

[0135] Referring to Figure 2 , it is a force-based independent variable pitch control block diagram. Set the axial thrust bias value F x,Target and the lateral thrust bias value F y,Target , which is set according to the unit load and control demand. Make the axial thrust and the axial thrust bias value, the lateral thrust and the lateral thrust bias value as the input of the feedback controller;

[0136] Define the axial thrust error Δe x as the difference between the real-time axial thrust and the axial thrust bias;

[0137] Define the lateral thrust error Δe y as the difference between the real-time lateral thrust and the lateral thrust bias;

[0138] The axial and lateral pitch angles β d and β q calculated by the feedback controller are coordinate system transformed, i.e. two-phase stationary coordinate system is converted into three-phase rotating coordinate system;

[0139] The formula of the feedback controller is as follows:

[0140]

[0141] In the above formula, k p is the proportional coefficient, k I is the integral coefficient, k d is the differential coefficient, Δe x (j) is the current axial thrust error and Δe y (j) is the current lateral thrust error, Δe ax (n) is the axial thrust error change rate and Δe ay (n) is the lateral thrust error change rate;

[0142] To prevent the control system from being unstable or the fluctuation amplitude being too large, the calculated variable pitch commands β d and β q are limited in amplitude;

[0143] The coordinate system conversion formula is as follows:

[0144]

[0145] In the above formula, θ is the azimuth angle of the impeller, and δ is the phase delay offset. In view of the response delay of the controller and the driver, the azimuth angle phase delay offset is introduced in the above formula to offset the time delay problem caused by the hardware and software of the wind turbine generator set.

[0146] The calculated variable pitch instruction in the three-phase coordinate system is superimposed on the unified variable pitch demand instruction, and finally transmitted to the variable pitch actuator.

[0147] S4, the variable pitch actuator controls the variable pitch action of the wind turbine generator set based on the unified variable pitch demand instruction.

[0148] Embodiment 2

[0149] Referring to Figure 3 Unlike Embodiment 1, in this embodiment, the tower bottom bending moment is further calculated based on the axial thrust and lateral thrust of the wind turbine generator set, and then the variable pitch instruction is calculated according to the tower bottom bending moment, including:

[0150] Based on the axial thrust and lateral thrust, the front and rear and left and right direction bending moments of the tower bottom of the wind turbine generator set are further calculated;

[0151] The relationship between the thrust and the bending moment is:

[0152] M y = F ax · h;

[0153] M x = F ay · h;

[0154] In the formula, M y and M x are the left and right and front and rear direction bending moments, and h is the tower height;

[0155] The front and rear load bias value M x,Target and the left and right load bias value M y,Target of the tower bottom are set, which are set according to the unit load and control demand. The calculated front and rear bending moments and front and rear load bias values and left and right bending moments and left and right load bias values are taken as inputs of the feedback controller;

[0156] The front and rear deviation Δe Mx of the tower bottom is defined as the difference between the real-time front and rear bending moment and the front and rear load bias value of the tower bottom;

[0157] The left and right deviation Δe My of the tower bottom is defined as the difference between the real-time left and right bending moment and the left and right load bias value of the tower bottom;

[0158] The pitch angles β d and βq Coordinate system transformation is performed, i.e. conversion from two-phase stationary coordinate system to three-phase rotating coordinate system;

[0159] The feedback controller formula is as follows:

[0160]

[0161] In the above formula, k p is a proportional coefficient, k I is an integral coefficient, k d is a differential coefficient, Δe Mx (j) is the front and rear bending moment error, Δe My (j) is the left and right bending moment error, Δe aMx (n) is the front and rear bending moment error rate, Δe aMy (n) is the left and right bending moment error rate.

[0162] The calculated pitch command β d and β q are subjected to amplitude limiting processing to prevent the control system from being unstable or having too large fluctuation amplitude;

[0163] The coordinate system conversion formula is as follows:

[0164]

[0165] In the above formula, θ is the blade azimuth angle, and δ is the phase delay; considering the response delay of the controller and the driver, an azimuth phase delay offset is introduced in the above formula to offset the time delay problem caused by the software and hardware of the wind turbine generator.

[0166] The calculated pitch command in the three-phase coordinate system is superimposed on the unified pitch demand command, and finally transmitted to the pitch actuator.

[0167] Embodiment 3

[0168] The embodiment discloses a wind turbine independent pitch control system for implementing the wind turbine independent pitch control method of embodiment 1 or embodiment 2, comprising:

[0169] The sway posture monitoring module is used for measuring the sway posture angle of the wind turbine nacelle and transmitting the measurement data to the data acquisition module through the transmission module;

[0170] The data acquisition module is used for acquiring the sway posture angle data and transmitting the acquisition data to the controller module through the transmission module;

[0171] The controller module calculates the nacelle axial thrust and lateral thrust according to the data obtained through the transmission, transmits the calculated pitch command to the pitch actuator through the feedback controller and the coordinate system conversion, and performs the following operations:

[0172] The axial and lateral thrusts of the wind turbine are calculated based on the sway angle of the nacelle;

[0173] The axial thrust calculation formula is:

[0174]

[0175] In the above formula, m t is the mass of the turbine, d t is the damping, and s t is the stiffness matrix; δx fa is the filtered fore-aft sway angle of the nacelle, is the fore-aft sway angular velocity of the nacelle, is the fore-aft sway angular acceleration of the nacelle, F ax is the axial thrust, M YB is the bending moment about the Y direction;

[0176] The lateral thrust calculation formula is:

[0177]

[0178] In the above formula, m t is the mass of the turbine, d t is the damping, and s t is the stiffness matrix; δx ss is the filtered side-to-side sway angle of the nacelle, is the side-to-side sway angular velocity of the nacelle, is the side-to-side sway angular acceleration of the nacelle, F ay is the lateral thrust, M ZB is the bending moment about the Z direction;

[0179] The filtered fore-aft sway angle of the nacelle and the filtered side-to-side sway angle of the nacelle are calculated according to the following formula:

[0180] δx fa = F(s)·δx x ;

[0181] δx ss = F(s)·δx y ;

[0182] In the above formula, F(s) is a low-pass and band-stop filter, δx x is the fore-aft sway angle, and δx y is the side-to-side sway angle;

[0183] 1) Set the axial thrust bias value and the lateral thrust bias value, and take the axial thrust and the axial thrust bias value and the lateral thrust and the lateral thrust bias value as the input of the feedback controller;

[0184] Define axial thrust deviation Δe x The difference between real-time axial thrust and axial thrust bias;

[0185] Define lateral thrust deviation Δe y The difference between real-time lateral thrust and lateral thrust bias;

[0186] The axial and lateral pitch angles β d and β q are transformed into the three-phase rotating coordinate system from the two-phase stationary coordinate system by the feedback controller;

[0187] The feedback controller formula is as follows:

[0188]

[0189] In the above formula, k p is the proportional coefficient, k I is the integral coefficient, and k d is the differential coefficient, Δe x (j) is the current axial thrust error, and Δe y (j) is the current lateral thrust error, Δe ax (n) is the axial thrust error rate of change, and Δe ay (n) is the lateral thrust error rate of change;

[0190] To prevent the control system from being unstable or having too large a fluctuation amplitude, the calculated variable pitch command β d and β q are subjected to amplitude limiting processing;

[0191] The coordinate system transformation formula is as follows:

[0192]

[0193] In the above formula, θ is the impeller azimuth angle, and δ is the phase delay offset;

[0194] The calculated variable pitch command in the three-phase coordinate system is superimposed on the unified variable pitch demand command, and finally transmitted to the variable pitch actuator.

[0195] 2) Based on the axial thrust and lateral thrust, further calculate the bending moments in front and back and left and right directions at the bottom of the wind turbine tower;

[0196] The relationship between thrust and bending moment is:

[0197] M y = F ax · h;

[0198] M x = F ay·h;

[0199] wherein M y , M x are left and right and front and back bending moments, h is the tower height;

[0200] The front and back load bias value and the left and right load bias value are set, and the calculated front and back bending moment and the front and back load bias value and the left and right bending moment and the left and right load bias value are taken as inputs of the feedback controller;

[0201] The front and back deviation Δe Mx of the tower is defined as the difference between the real-time front and back bending moment and the front and back load bias value;

[0202] The left and right deviation Δe My of the tower is defined as the difference between the real-time left and right bending moment and the left and right load bias value;

[0203] The pitch angle β d and β q in the front and back and left and right directions calculated by the feedback controller are subjected to coordinate system transformation, i.e. conversion from two-phase static coordinate system to three-phase rotating coordinate system;

[0204] The feedback controller formula is as follows:

[0205]

[0206] In the above formula, k p is a proportional coefficient, k I is an integral coefficient, k d is a differential coefficient, Δe Mx (j) is the front and back bending moment error at the current moment, Δe My (j) is the left and right bending moment error at the current moment, Δe aMx (n) is the front and back bending moment error change rate, and Δe aMy (n) is the left and right bending moment error change rate.

[0207] To prevent the control system from being unstable or the fluctuation amplitude from being too large, the calculated pitch instructions β d and β q are subjected to amplitude limiting processing;

[0208] The coordinate system conversion formula is as follows:

[0209]

[0210] In the above formula, θ is the blade azimuth angle, and δ is the phase delay;

[0211] The calculated pitch instructions in the three-phase coordinate system are superimposed into the unified pitch demand instruction, and finally transmitted to the pitch actuator.

[0212] Transmission module, used for communication and data transmission between modules;

[0213] The pitch actuator controls the pitch of the wind turbine according to the pitch instruction.

[0214] Example 3

[0215] This embodiment discloses a non-transitory computer-readable medium storing instructions. When the instructions are executed by a processor, the steps of the independent pitch control method for a wind turbine generator set according to Embodiment 1 or Embodiment 2 are performed.

[0216] The non-transitory computer-readable medium in this embodiment can be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a USB flash drive, a mobile hard disk, or other media.

[0217] Example 4

[0218] This embodiment discloses a computing device, including a processor and a memory for storing a program executable by the processor. When the processor executes the program stored in the memory, the independent pitch control method for a wind turbine described in Example 1 or Example 2 is implemented.

[0219] The computing device described in this embodiment may be a desktop computer, a laptop computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with a processor function.

[0220] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any changes made based on the shape and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wind turbine independent pitch control method, characterized in that: The following steps are involved: S1, collect the sway attitude angle data of the wind turbine in four directions; S2. Calculate the axial thrust and lateral thrust of the wind turbine generator system based on the collected data; S3. Calculate the pitch command in three-phase coordinates based on the axial thrust and lateral thrust of the wind turbine generator set, superimpose the pitch command in the three-phase coordinate system onto the unified pitch demand command, and transmit it to the pitch actuator; An axial thrust offset value and a lateral thrust offset value are set so that the axial thrust and the axial thrust offset value, the lateral thrust and the lateral thrust offset value serve as inputs of a feedback controller; Definition of axial thrust deviation Δe x is the difference between the real-time axial thrust and the axial thrust offset; Define lateral thrust deviation Δe y is the difference between the real-time lateral thrust and the lateral thrust offset; The axial and lateral pitch angles β calculated by the feedback controller are d and β q Perform coordinate system transformation, that is, convert the two-phase stationary coordinate system into a three-phase rotating coordinate system; The feedback controller formula is as follows: In the above formula, k p is the proportionality coefficient, k I is the integration coefficient, k d is the differential coefficient, Δe x (j) is the axial thrust error and Δe at the current moment y (j) is the lateral thrust error at the current moment, Δe ax (n) is the axial thrust error change rate and Δe ay (n) is the rate of change of lateral thrust error; To prevent the control system from becoming unstable or fluctuating too much, the calculated pitch command β d and β q Perform limiting processing; The coordinate system conversion formula is as follows: In the above formula, θ is the impeller azimuth angle, and δ is the phase delay offset; The calculated pitch control command in the three-phase coordinate system is added to the unified pitch control demand command, and finally transmitted to the pitch control actuator; S4. The pitch actuator controls the wind turbine pitch action based on the unified pitch demand instruction.

2. A wind turbine independent pitch control method according to claim 1, characterized in that: The step S1 comprises: A dynamic tilt sensor is installed at the nacelle of the wind turbine to obtain the swaying attitude angle data of the wind turbine in the front-to-back direction and the left-to-right direction.

3. The independent pitch control method for a wind turbine according to claim 1, characterized in that: The step S2 comprises: Calculate the axial and lateral thrust of the wind turbine based on the swaying attitude angle of the nacelle; The axial thrust calculation formula is: In the above formula, m t is the mass of the unit, d t is the damping and s t is the stiffness matrix; δx fa To filter the cabin's forward and backward shaking attitude angle, is the angular velocity of the cabin's forward and backward shaking attitude, F is the angular acceleration of the cabin's forward and backward shaking attitude, ax is the axial thrust, M YB is the rotational bending moment around the Y direction; The lateral thrust calculation formula is: In the above formula, m t is the unit mass, d t is the damping and s t is the stiffness matrix; δx ss To filter the left and right shaking attitude angle of the cabin, is the angular velocity of the cabin's left and right shaking attitude, F is the angular acceleration of the cabin's left and right shaking attitude, ay is the lateral thrust, M ZB is the rotational bending moment around the Z direction; The calculation formulas for the front and rear swaying attitude angle of the filter cabin and the left and right swaying attitude angle of the filter cabin are as follows: δx fa =F(s)·δx x ; δx ss =F(s)·δx y ; In the above formula, F(s) is a low-pass and band-stop filter, δx x is the forward and backward shaking angle, δx y The left and right shaking angle.

4. The independent pitch control method for a wind turbine according to claim 1, characterized in that: The step S3 comprises: Based on the axial thrust and lateral thrust, the bending moments at the bottom of the wind turbine tower in the front-to-back and left-to-right directions are further calculated; The relationship between thrust and bending moment is: M y =F ax ·h; M x =F ay ·h; Where M y , M x are the bending moments in the left and right and front and back directions respectively, and h is the tower height; Setting the front and rear load offset values ​​and the left and right load offset values ​​of the tower bottom, and using the calculated front and rear bending moments and front and rear load offset values, the left and right bending moments and the left and right load offset values ​​of the tower bottom as inputs to the feedback controller; Define the deviation Δe before and after the tower bottom Mx is the difference between the real-time front-to-back bending moment of the tower base and the front-to-back load offset value of the tower base; Define the left and right deviation Δe of the tower bottom My The difference between the real-time left and right bending moments at the tower bottom and the left and right load offset values ​​at the tower bottom; The pitch angle β in the front and rear and left and right directions calculated by the feedback controller d and β q Perform coordinate system transformation, that is, convert the two-phase stationary coordinate system into a three-phase rotating coordinate system; The feedback controller formula is as follows: In the above formula, k p is the proportionality coefficient, k I is the integration coefficient, k d is the differential coefficient, Δe Mx (j) is the bending moment error before and after the current moment and Δe My (j) is the bending moment error at the current moment, Δe aMx (n) is the rate of change of the front and rear bending moment error and Δe aMy (n) is the rate of change of left and right bending moment errors; To prevent the control system from becoming unstable or fluctuating too much, the calculated pitch command β d and β q Perform limiting processing; The coordinate system conversion formula is as follows: In the above formula, θ is the impeller azimuth angle, and δ is the phase delay; The calculated pitch control command in the three-phase coordinate system is added to the unified pitch control demand command and finally transmitted to the pitch control actuator.

5. A wind turbine independent pitch control system, characterized in that: A method for implementing independent pitch control of a wind turbine generator set according to any one of claims 1 to 4, comprising: The sway attitude monitoring module is used to measure the sway attitude angle of the wind turbine nacelle and transmit the measurement data to the data acquisition module through the transmission module; The data acquisition module is used to collect the shaking posture angle data and transmit the collected data to the controller module through the transmission module; The controller module calculates the axial and lateral thrust of the nacelle based on the transmitted data. It transmits the calculated pitch control instructions to the pitch control actuator through the feedback controller and coordinate system conversion, and performs the following operations: Calculate the axial and lateral thrust of the wind turbine based on the swaying attitude angle of the nacelle; The axial thrust calculation formula is: In the above formula, m t is the unit mass, d t is the damping and s t is the stiffness matrix; δx fa To filter the cabin's forward and backward shaking attitude angle, is the angular velocity of the cabin's forward and backward shaking attitude, F is the angular acceleration of the cabin's forward and backward shaking attitude, ax is the axial thrust, M YB is the rotational bending moment around the Y direction; The lateral thrust calculation formula is: In the above formula, m t is the mass of the unit, d t is the damping and s t is the stiffness matrix; δx ss To filter the left and right shaking attitude angle of the cabin, is the angular velocity of the cabin's left and right shaking attitude, F is the angular acceleration of the cabin's left and right shaking attitude, ay is the lateral thrust, M ZB is the rotational bending moment around the Z direction; The calculation formulas for the front and rear swaying attitude angle of the filter cabin and the left and right swaying attitude angle of the filter cabin are as follows: δx fa =F(s)·δx x ; δx ss =F(s)·δx y ; In the above formula, F(s) is a low-pass and band-stop filter, δx x is the forward and backward shaking angle, δx y is the left and right shaking angle; An axial thrust offset value and a lateral thrust offset value are set so that the axial thrust and the axial thrust offset value, the lateral thrust and the lateral thrust offset value serve as inputs of a feedback controller; Definition of axial thrust deviation Δe x is the difference between the real-time axial thrust and the axial thrust offset; Define lateral thrust deviation Δe y is the difference between the real-time lateral thrust and the lateral thrust offset; The axial and lateral pitch angles β calculated by the feedback controller are d and β q Perform coordinate system transformation, that is, convert the two-phase stationary coordinate system into a three-phase rotating coordinate system; The feedback controller formula is as follows: In the above formula, k p is the proportionality coefficient, k I is the integration coefficient, k d is the differential coefficient, Δe x (j) is the axial thrust error and Δe at the current moment y (j) is the lateral thrust error at the current moment, Δe ax (n) is the axial thrust error change rate and Δe ay (n) is the rate of change of lateral thrust error; To prevent the control system from becoming unstable or fluctuating too much, the calculated pitch command β d and β q Perform limiting processing; The coordinate system conversion formula is as follows: In the above formula, θ is the impeller azimuth angle, and δ is the phase delay offset; The calculated pitch control command in the three-phase coordinate system is added to the unified pitch control demand command, and finally transmitted to the pitch control actuator; Transmission module, used for communication and data transmission between modules; The pitch actuator controls the pitch of the wind turbine according to the pitch instruction.

6. The independent pitch control system for a wind turbine according to claim 5, characterized in that: The controller module performs the following operations: Based on the axial thrust and lateral thrust, the bending moments at the bottom of the wind turbine tower in the front-to-back and left-to-right directions are further calculated; The relationship between thrust and bending moment is: M y =F ax ·h; M x =F ay ·h; Where M y , M x are the bending moments in the left and right and front and back directions respectively, and h is the tower height; Setting the front and rear load offset values ​​and the left and right load offset values ​​of the tower bottom, and using the calculated front and rear bending moments and front and rear load offset values, the left and right bending moments and the left and right load offset values ​​of the tower bottom as inputs to the feedback controller; Define the deviation Δe before and after the tower bottom Mx is the difference between the real-time front-to-back bending moment of the tower base and the front-to-back load offset value of the tower base; Define the left and right deviation of the tower bottom Δe My The difference between the real-time left and right bending moments at the tower bottom and the left and right load offset values ​​at the tower bottom; The pitch angle β in the front and rear and left and right directions calculated by the feedback controller d and β q Perform coordinate system transformation, that is, convert the two-phase stationary coordinate system into a three-phase rotating coordinate system; The feedback controller formula is as follows: In the above formula, k p is the proportionality coefficient, k I is the integration coefficient, k d is the differential coefficient, Δe Mx (j) is the bending moment error before and after the current moment and Δe My (j) is the bending moment error at the current moment, Δe aMx (n) is the rate of change of the front and rear bending moment error and Δe aMy (n) is the rate of change of left and right bending moment errors; To prevent the control system from becoming unstable or fluctuating too much, the calculated pitch command β d and β q Perform limiting processing; The coordinate system conversion formula is as follows: In the above formula, θ is the impeller azimuth angle, and δ is the phase delay; The calculated pitch control command in the three-phase coordinate system is added to the unified pitch control demand command and finally transmitted to the pitch control actuator.

7. A non-transitory computer-readable medium storing instructions, characterized in that: When the instruction is executed by the processor, the steps of the independent pitch control method for a wind turbine generator set according to any one of claims 1 to 4 are performed.

8. A computing device comprising a processor and a memory for storing a program executable by the processor, characterized in that: When the processor executes the program stored in the memory, the independent pitch control method for a wind turbine generator set according to any one of claims 1 to 4 is implemented.

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