A method and system for variable pitch assisted yaw wind following control of a wind turbine

Abstract

The application discloses a kind of wind turbine's auxiliary yawing of variable pitch to wind control method and system, comprising: based on the direction of measured cabin and average wind direction, optimal yaw trajectory is planned, and cabin yaw target angle is output;According to cabin yaw target angle, the yaw variable pitch instruction of each blade is calculated, for generating yaw moment in wind wheel plane to promote cabin yawing;According to the yaw rate of cabin actual yawing, the yaw variable pitch instruction of each blade is calculated, for controlling yaw rate smooth in cabin yawing process;After the superposition of the yaw variable pitch instruction of each blade and yaw variable pitch instruction of each blade, the superposition of the unified variable pitch instruction given by unit is carried out, and the final variable pitch instruction of each blade is obtained;The final variable pitch instruction of each blade is transmitted to the variable pitch system of unit, and the variable pitch of blade is driven by variable pitch system, to realize driving cabin yawing.The application can effectively solve the problem of insufficient yaw driving capacity, and reduce the number of yaw driving motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation, and particularly refers to a variable-pitch auxiliary yaw wind-against control method and system for a wind turbine generator, a storage medium and a computing device. BACKGROUND

[0002] At present, wind turbine generators are gradually developing towards large-scale, and the super-long blades make the wind-swept area of the wind turbine generator larger, and the power generation capacity and full-load hours of the unit are significantly improved. However, after the large-scale development of the wind turbine generator, the load received by the wind wheel also increases sharply. This has caused many problems, among which the yaw system is insufficient in driving capacity due to higher load. Although the driving capacity of the yaw system can be improved by increasing the number of yaw driving motors, the overall cost is also increased, and the space for arranging the yaw driving motors is limited, which brings great technical difficulties to the design of the yaw system. SUMMARY

[0003] The first object of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a variable-pitch auxiliary yaw wind-against control method for a wind turbine generator. Based on the measured nacelle direction and average wind direction, an optimal yaw trajectory is planned, and a driving nacelle yaw is realized by superimposing the variable-pitch command, which can effectively solve the problem of insufficient yaw driving capacity and reduce the number of yaw driving motors.

[0004] The second object of the present application is to provide a variable-pitch auxiliary yaw wind-against control system for a wind turbine generator.

[0005] The third object of the present application is to provide a storage medium.

[0006] The fourth object of the present application is to provide a computing device.

[0007] The first object of the present application is achieved by the following technical scheme: a variable-pitch auxiliary yaw wind-against control method for a wind turbine generator, comprising:

[0008] Based on the measured nacelle direction and average wind direction, an optimal yaw trajectory is planned, and a nacelle yaw target angle is output;

[0009] According to the nacelle yaw target angle, a yaw variable-pitch command for each blade is calculated, which is used to generate a yaw moment in the wind wheel plane to push the nacelle yaw, so as to achieve the purpose of nacelle wind-against;

[0010] According to the actual yaw rate of the nacelle, a yaw resistance variable-pitch command for each blade is calculated, which is used to control the smoothness of the yaw rate during the nacelle yaw, so as to achieve the purpose of nacelle uniform-speed yaw wind-against;

[0011] After superimposing the yaw variable-pitch command and the yaw resistance variable-pitch command for each blade, and superimposing the unified variable-pitch command given by the unit, the final variable-pitch command for each blade is obtained.

[0012] The final pitch command of each blade is transmitted to the pitch system of the unit, and the pitch system drives the blades to pitch to realize the yaw of the nacelle.

[0013] Further, in order to make the direction of the nacelle track the average wind direction, the optimal yaw trajectory from the current direction of the nacelle to the average wind direction needs to be calculated, when the direction of the nacelle coincides with the average wind direction, the yaw error is zero, at this time the wind turbine is directly against the wind direction; the average wind direction is obtained by filtering the real-time wind direction collected by the nacelle wind direction sensor through an average value filter.

[0014] Further, the direction of the nacelle is directly measured by the nacelle north sensor.

[0015] Further, the calculation formula of the average wind direction is as follows:

[0016]

[0017] In the above formula, t represents a time variable, and Δt represents a time step, wind (t) represents the real-time wind direction collected by the nacelle wind direction sensor, represents the average wind direction after filtering by the average value filter, and F θ (s) represents a low-pass filter.

[0018] Further, the low-pass filter is one or a combination of a first-order low-pass filter, a second-order low-pass filter, and an average value filter.

[0019] Further, the optimal yaw trajectory is divided into four working modes, mode 0, mode 1, mode-1 and mode 2, and the default working mode is mode 0 at the initialization state, and the nacelle yaw target angle is in the same direction as the direction of the nacelle at the initial time;

[0020] Mode 0: the nacelle yaw target angle remains constant until the deviation between the average wind direction and the nacelle yaw target angle exceeds the set yaw error threshold, then the working mode is switched; if the deviation is greater than zero, mode 1 is switched; if the deviation is less than zero, mode-1 is switched; when the deviation between the average wind direction and the nacelle yaw target angle does not exceed the set yaw error threshold, the working mode remains mode 0;

[0021]

[0022]

[0023] In the above formula, t represents a time variable, Δt represents a time step, represents the current time nacelle yaw target angle, Mode represents mode variable, H represents yaw error threshold, represents average wind direction after average value filter, represents absolute value of difference between average wind direction and yaw target angle, used to measure deviation between average wind direction and yaw target angle of nacelle;

[0024] Mode 1: the yaw target angle of nacelle keeps constant rate output, the rate is positive, the nacelle tracks the average wind direction in clockwise direction until the deviation between the average wind direction and the yaw target angle of nacelle is close to or equal to zero, then the working mode is switched to mode 2; a very small positive number is applied, if the deviation is less than the positive number, it is judged as close to or equal to zero; if the deviation is greater than the positive number, the current working mode 1 is kept unchanged;

[0025]

[0026]

[0027] In the above formula, v represents the yaw rate of nacelle, ε represents the minimum threshold of stopping yaw, which is set as a very small positive number;

[0028] Mode-1: the yaw target angle of nacelle keeps constant rate output, the rate is negative, the nacelle tracks the average wind direction in counterclockwise direction until the deviation between the average wind direction and the yaw target angle of nacelle is close to or equal to zero, then the working mode is switched to mode 2; a very small positive number is applied, if the deviation is less than the positive number, it is judged as close to or equal to zero; if the deviation is greater than the positive number, the current working mode-1 is kept unchanged;

[0029]

[0030]

[0031] Mode 2: when entering mode 2, the yaw target angle of nacelle keeps constant value unchanged, a timer is initialized to zero and starts to count, if the time of the timer exceeds the set yaw rest time threshold, the mode is switched back to mode 0, the purpose of mode 2 is to ensure that there is enough cooling time before starting yaw action again;

[0032]

[0033]

[0034] In the above formula, Timer(t) represents the timer, T0 represents the yaw rest time threshold.

[0035] Further, based on the output yaw target angle of the nacelle, compared with the nacelle direction, a yaw driving moment is obtained through proportional and integral operation, and the calculation formula of the yaw driving moment is as follows:

[0036]

[0037] In the above formula, t represents a time variable, M yaw (t) represents a yaw driving moment, k p represents a yaw wind control proportional gain, k i represents a yaw wind control integral gain, represents the yaw target angle of the nacelle at the current moment, represents the nacelle direction at the current moment, and ∫(·)dt represents an integral operation on time;

[0038] A yaw driving moment is generated on the wind wheel, which needs to be generated by applying different yaw pitch instructions to three blades. Since the thrust of each blade is different, a yaw driving moment is generated in the wind wheel plane. The yaw pitch instruction calculation formula of the three blades is as follows:

[0039]

[0040] In the above formula, Δβ 1,yaw represents the yaw pitch instruction of blade 1, Δβ 2,yaw represents the yaw pitch instruction of blade 2, and Δβ 3,yaw represents the yaw pitch instruction of blade 3, H β represents a bending moment to pitch conversion coefficient, θ A (t) represents the azimuth angle of blade 1, which is measured by an azimuth angle sensor, θ ph represents a phase lead compensation.

[0041] Further, based on the measured nacelle direction, a nacelle yaw rate is obtained through a differential operation, and a yaw plus resistance moment is obtained through a proportional operation. The calculation formula of the yaw plus resistance moment is as follows:

[0042]

[0043] In the above formula, M damper (t) represents a yaw plus resistance moment, k damper represents a yaw plus resistance control proportional gain, F damper (s) represents a yaw plus resistance low-pass filter, represents a differential operation on the nacelle direction, represents the nacelle direction at the current moment;

[0044] The yaw plus drag moment is generated on the wind wheel, and different yaw plus drag variable pitch instructions are applied to the three blades, and since the thrust of each blade is different, a yaw plus drag moment is generated in the wind wheel plane, and the yaw plus drag variable pitch instruction calculation formula of the three blades is as follows:

[0045]

[0046] In the above formula, Δβ 1,damper represents the yaw plus drag variable pitch instruction of blade 1, Δβ 2,damper represents the yaw plus drag variable pitch instruction of blade 2, Δβ 3,damper represents the yaw plus drag variable pitch instruction of blade 3, H β represents the bending moment to variable pitch conversion coefficient, θ A (t) represents the azimuth angle of blade 1, which is measured by an azimuth angle sensor, θ ph represents the phase lead compensation.

[0047] Further, the calculation formula of the final variable pitch instruction is as follows:

[0048]

[0049] In the above formula, represents the final variable pitch instruction of blade 1, represents the final variable pitch instruction of blade 2, represents the final variable pitch instruction of blade 3, Δβ 1,yaw represents the yaw variable pitch instruction of blade 1, Δβ 2,yaw represents the yaw variable pitch instruction of blade 2, Δβ 3,yaw represents the yaw variable pitch instruction of blade 3, Δβ 1,damper represents the yaw plus drag variable pitch instruction of blade 1, Δβ 2,damper represents the yaw plus drag variable pitch instruction of blade 2, Δβ 3,damper represents the yaw plus drag variable pitch instruction of blade 3, β c represents the unified variable pitch instruction.

[0050] The second object of the application is achieved by the following technical scheme: a variable pitch auxiliary yaw wind-against control system of a wind turbine, which is used to realize the variable pitch auxiliary yaw wind-against control method of the wind turbine, and comprises:

[0051] A yaw trajectory planning module plans an optimal yaw trajectory based on the measured nacelle direction and average wind direction, and outputs a nacelle yaw target angle;

[0052] A yaw wind-against control module calculates the yaw variable pitch instruction of each blade according to the nacelle yaw target angle, so as to generate a yaw moment in the wind wheel plane to push the nacelle to yaw, so as to achieve the purpose of nacelle wind-against;

[0053] The yaw active drag module calculates the yaw drag pitch control command for each blade based on the actual yaw rate of the nacelle. This is used to control the yaw rate to be stable during the yawing process of the nacelle, so as to achieve the purpose of uniform yaw of the nacelle into the wind.

[0054] The pitch command superposition module is used to superimpose the yaw pitch command of each blade with the yaw resistance pitch command, and then superimpose it with the unified pitch command given by the unit to obtain the final pitch command for each blade.

[0055] The third object of the present invention is achieved through the following technical solution: a storage medium stores a program, and when the program is executed by a processor, the above-mentioned variable pitch assisted yaw wind control method of the wind turbine is implemented.

[0056] The fourth purpose of the present invention is achieved through the following technical solution: a computing device, comprising a processor and a memory for storing a program executable by the processor, wherein when the processor executes the program stored in the memory, the above-mentioned variable pitch assisted yaw wind control method of the wind turbine is implemented.

[0057] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0058] 1. The present invention drives the nacelle to yaw by superimposing a pitch command on the pitch, thereby solving the problem of insufficient yaw drive capability, reducing the number of yaw drive motors, and lowering the cost of the entire machine.

[0059] 2. The present invention has good yaw-to-wind accuracy by calculating the optimal yaw trajectory, making yaw-to-wind safe and reliable.

[0060] 3. The present invention controls the yaw rate to stabilize the yaw process of the cabin and reduce the fluctuation and vibration of the yaw rate during the yaw process. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 An architectural diagram of the system of the present invention. DETAILED DESCRIPTION

[0062] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0063] Example 1

[0064] This embodiment discloses a method for wind turbine generator system to control pitch-assisted yaw in response to wind, the details of which are as follows:

[0065] 1) In order to make the direction of the nacelle track the average wind direction, the optimal yaw trajectory from the current nacelle direction to the average wind direction needs to be calculated; when the nacelle direction coincides with the average wind direction, the yaw error is zero, at this time the wind turbine is directly against the wind direction; the nacelle direction is obtained by directly measuring the nacelle-to-north sensor; the average wind direction is obtained by first collecting the real-time wind direction through the nacelle wind vane, and then filtering the real-time wind direction through an average value filter.

[0066] Firstly, the current average wind direction is calculated, and the calculation formula is as follows:

[0067]

[0068] In the above formula, t represents a time variable, and θ wind (t) represents the real-time wind direction collected by the nacelle wind vane, represents the average wind direction after filtering by the average value filter, and F θ (s) represents a low-pass filter.

[0069] The low-pass filter can be one or a combination of a first-order low-pass filter, a second-order low-pass filter, and an average value filter.

[0070] Secondly, the optimal planning of the yaw running trajectory (i.e., planning the optimal yaw trajectory) is performed, and the nacelle yaw target angle is output.

[0071] This part is subdivided into four working modes, namely mode 0, mode 1, mode-1 and mode 2, and the default working mode is mode 0 at the initialization state, and the nacelle yaw target angle is initially in the same direction as the nacelle direction;

[0072] Mode 0: the nacelle yaw target angle remains constant, until the deviation between the average wind direction and the nacelle yaw target angle exceeds the set yaw error threshold, then the working mode is switched; if the deviation is greater than zero, mode 1 is switched; if the deviation is less than zero, mode-1 is switched; when the deviation between the average wind direction and the nacelle yaw target angle does not exceed the set yaw error threshold, the working mode remains mode 0;

[0073]

[0074]

[0075] In the above formula, t represents a time variable, and Δt represents a time step, represents the nacelle yaw target angle at the current time, represents the nacelle yaw target angle at the previous time, Mode represents a mode variable, and H represents a yaw error threshold, represents the average wind direction after filtering by the average value filter, |Δ| = |ωtarget-ωav|, where ωtargetis the target yaw angle of the nacelle, and ωavis the average wind direction.

[0076] Mode 1: The target yaw angle of the nacelle keeps constant rate output, the rate is positive, the nacelle tracks the average wind direction in clockwise direction, until the deviation between the average wind direction and the target yaw angle of the nacelle is close to or equal to zero (i.e. almost zero), then switch the working mode to Mode 2; a very small positive number is applied, if the deviation is less than the positive number, then the deviation is close to or equal to zero; if the deviation is greater than the positive number, then keep the current working mode 1 unchanged.

[0077]

[0078]

[0079] In the above formula, v represents the nacelle yaw rate, and ε represents the minimum threshold of stopping yaw, which is set to a very small positive number.

[0080] Mode-1: The target yaw angle of the nacelle keeps constant rate output, the rate is negative, the nacelle tracks the average wind direction in counterclockwise direction, until the deviation between the average wind direction and the target yaw angle of the nacelle is close to or equal to zero, then switch the working mode to Mode 2; a very small positive number is applied, if the deviation is less than the positive number, then the deviation is close to or equal to zero; if the deviation is greater than the positive number, then keep the current working mode-1 unchanged.

[0081]

[0082]

[0083] Mode 2: When entering Mode 2, the target yaw angle of the nacelle keeps constant value unchanged, a timer is initialized to zero and starts to count, if the time of the timer exceeds the set yaw rest time threshold, then switch the mode back to Mode 0, the purpose of Mode 2 is to ensure that there is enough cooling time before starting the yaw action again.

[0084]

[0085]

[0086] In the above formula, Timer(t) represents the timer, and T0represents the yaw rest time threshold.

[0087] 2) According to the target yaw angle of the nacelle, calculate the yaw pitch command of each blade, which is used to generate a yaw moment in the wind wheel plane to push the nacelle yaw, so as to achieve the purpose of nacelle wind alignment.

[0088] First, calculate the yaw driving moment.

[0089] Based on the output of the nacelle yaw target angle, compared with the nacelle direction, the yaw driving moment is obtained through proportional and integral operation, and the calculation formula of the yaw driving moment is as follows:

[0090]

[0091] In the above formula, t represents a time variable, M yaw (t) represents a yaw driving moment, k p represents a yaw wind control proportional gain, k i represents a yaw wind control integral gain, represents the nacelle yaw target angle at the current time, represents the nacelle direction at the current time, and ∫(·)dt represents the integral operation on time.

[0092] Secondly, the yaw pitch instructions of the three blades are calculated.

[0093] The yaw driving moment is generated on the wind wheel, which needs to be generated by applying different yaw pitch instructions to the three blades. Since the thrust of each blade is different, a yaw driving moment is generated in the wind wheel plane. The yaw pitch instruction calculation formula of the three blades is as follows:

[0094]

[0095] In the above formula, Δβ 1,yaw represents the yaw pitch instruction of blade 1, Δβ 2,yaw represents the yaw pitch instruction of blade 2, and Δβ 3,yaw represents the yaw pitch instruction of blade 3, H β represents the bending moment to pitch conversion coefficient, θ A (t) represents the azimuth angle of blade 1, which is measured by the azimuth angle sensor, θ ph represents the phase lead compensation.

[0096] 3) According to the actual yaw rate of the nacelle, the yaw plus resistance pitch instruction of each blade is calculated, which is used to control the smooth yaw rate during the nacelle yaw process, so as to achieve the purpose of nacelle uniform speed yaw to wind.

[0097] Firstly, the yaw plus resistance moment is calculated.

[0098] Based on the measured nacelle direction, the nacelle yaw rate is obtained through differential operation, and the yaw plus resistance moment is obtained through proportional operation. The calculation formula of the yaw plus resistance moment is as follows:

[0099]

[0100] In the above formula, M damper (t) represents a yaw plus resistance moment, k damperrepresents yaw plus drag control proportional gain, F damper (s) represents yaw plus drag low pass filter, represents the yaw direction of the cabin, represents the yaw direction of the cabin at the current time.

[0101] Secondly, the yaw plus drag variable pitch command of the three blades is calculated.

[0102] The yaw plus drag moment is generated on the wind wheel, and different yaw plus drag variable pitch commands are applied to the three blades to generate a yaw plus drag moment in the wind wheel plane. The yaw plus drag variable pitch command calculation formula of the three blades is as follows:

[0103]

[0104] In the above formula, Δβ 1,damper represents the yaw plus drag variable pitch command of blade 1, Δβ 2,damper represents the yaw plus drag variable pitch command of blade 2, Δβ 3,damper represents the yaw plus drag variable pitch command of blade 3, H β represents the bending moment to variable pitch conversion coefficient, θ A (t) represents the azimuth angle of blade 1, which is measured by the azimuth angle sensor, θ ph represents the phase lead compensation.

[0105] 4) The yaw variable pitch command of each blade is superimposed with the yaw plus drag variable pitch command, and then superimposed with the unified variable pitch command given by the unit to obtain the final variable pitch command of each blade;

[0106] The calculation formula of the final variable pitch command is as follows:

[0107]

[0108] In the above formula, represents the final variable pitch command of blade 1, represents the final variable pitch command of blade 2, represents the final variable pitch command of blade 3, Δβ 1,yaw represents the yaw variable pitch command of blade 1, Δβ 2,yaw represents the yaw variable pitch command of blade 2, Δβ 3,yaw represents the yaw variable pitch command of blade 3, Δβ 1,damper represents the yaw plus drag variable pitch command of blade 1, Δβ 2,damper represents the yaw plus drag variable pitch command of blade 2, Δβ 3,damper represents the yaw plus drag variable pitch command of blade 3, β c represents the unified variable pitch command.

[0109] 5) transmit the final pitch command of each blade to the pitch system of the unit, drive the blades to pitch by the pitch system, and realize driving the nacelle to yaw.

[0110] Embodiment 2

[0111] The embodiment discloses a pitch-assisted yaw wind-against control system of a wind turbine, which is used to realize the pitch-assisted yaw wind-against control method of the wind turbine in the embodiment 1, as shown in the figure, comprising: Figure 1

[0112] a yaw trajectory planning module, which plans an optimal yaw trajectory based on the measured nacelle direction and the average wind direction, and outputs a nacelle yaw target angle;

[0113] a yaw wind-against control module, which calculates a yaw pitch command of each blade according to the nacelle yaw target angle, so as to generate a yaw moment in the rotor plane to push the nacelle to yaw, and achieve the purpose of nacelle wind-against;

[0114] a yaw active resistance module, which calculates a yaw resistance pitch command of each blade according to the actual yaw rate of the nacelle, so as to control the yaw rate to be smooth during the nacelle yaw, and achieve the purpose of nacelle uniform-speed yaw wind-against;

[0115] a pitch command superposition module, which is used to superimpose the yaw pitch command and the yaw resistance pitch command of each blade, and then superimpose the unified pitch command given by the unit, to obtain the final pitch command of each blade.

[0116] Embodiment 3

[0117] The embodiment discloses a storage medium, which stores a program, and the program is executed by a processor to realize the pitch-assisted yaw wind-against control method of the wind turbine in the embodiment 1.

[0118] The storage medium in the embodiment can be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a U disk, a mobile hard disk, and the like.

[0119] Embodiment 4

[0120] The embodiment discloses a computing device, which comprises a processor and a memory for storing a program executable by the processor, and the processor executes the program stored in the memory to realize the pitch-assisted yaw wind-against control method of the wind turbine in the embodiment 1.

[0121] ​The computing device described in the embodiments can be a desktop computer, a notebook computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal device with processor function.

[0122] The above embodiments are preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement methods and should be included in the protection scope of the present application.

Claims

1. A pitch-assisted yaw wind control method for a wind turbine, characterized in that: include: Based on the measured cabin direction and average wind direction, the optimal yaw trajectory is planned and the cabin yaw target angle is output; According to the nacelle yaw target angle, the yaw pitch command of each blade is calculated to generate a yaw moment on the rotor plane to push the nacelle to yaw, so that the nacelle faces the wind; According to the actual yaw rate of the nacelle, the yaw resistance and pitch control instructions of each blade are calculated to control the yaw rate to be stable during the yaw process of the nacelle, so as to achieve the purpose of uniform yaw of the nacelle into the wind; The yaw pitch control command of each blade is superimposed with the yaw resistance pitch control command, and then superimposed with the unified pitch control command given by the unit to obtain the final pitch control command of each blade; The final pitch change command of each blade is transmitted to the unit's pitch change system, and the pitch change system drives the blade to change pitch to achieve the yaw of the cabin.

2. The pitch-assisted yaw wind control method for a wind turbine according to claim 1, characterized in that: In order to make the direction of the nacelle track the average wind direction, it is necessary to calculate the optimal yaw trajectory from the current nacelle direction to the average wind direction. When the nacelle direction coincides with the average wind direction, the yaw error is zero, and the wind turbine is facing the wind direction. The average wind direction is obtained by first collecting the real-time wind direction through the nacelle wind vane and then filtering this real-time wind direction through the average value filter.

3. The pitch-assisted yaw wind control method for a wind turbine according to claim 2, characterized in that: The cabin direction is obtained by directly measuring the cabin north sensor.

4. The pitch-assisted yaw wind control method for a wind turbine according to claim 2, characterized in that: The calculation formula of the average wind direction is as follows: In the above formula, t represents the time variable, θ wind (t) represents the real-time wind direction collected by the cabin wind vane, Indicates the average wind direction after the average filter, F θ (s) represents a low-pass filter.

5. The pitch-assisted yaw wind control method for a wind turbine according to claim 4, characterized in that: The low-pass filter is a combination of one or more of a first-order low-pass filter, a second-order low-pass filter, and an average filter.

6. The pitch-assisted yaw wind control method for a wind turbine according to claim 1, characterized in that: Planning the optimal yaw trajectory is divided into four working modes: Mode 0, Mode 1, Mode -1, and Mode 2. The default working mode is Mode 0 during initialization. The cabin yaw target angle is initially in the same direction as the cabin direction. Mode 0: The cabin yaw target angle remains constant until the deviation between the average wind direction and the cabin yaw target angle exceeds the set yaw error threshold, then the system switches to the working mode; if the deviation is greater than zero, the system switches to mode 1; if the deviation is less than zero, the system switches to mode -1; When the deviation between the average wind direction and the cabin yaw target angle does not exceed the set yaw error threshold, the working mode is maintained at mode 0; In the above formula, t represents the time variable, Δt represents the time step, Indicates the cabin yaw target angle at the current moment, Indicates the cabin yaw target angle at the previous moment, Mode indicates the mode variable, H indicates the yaw error threshold, represents the average wind direction after passing through the average filter, It represents the absolute value of the difference between the mean wind direction and the yaw target angle, and is used to measure the deviation between the mean wind direction and the yaw target angle of the cabin; Mode 1: The cabin yaw target angle is output at a constant rate, with a positive rate. The system yaws clockwise to track the average wind direction until the deviation between the average wind direction and the cabin yaw target angle is close to or equal to zero. Then, the operating mode is switched to Mode 2. A very small positive number is applied. If the deviation is less than this positive number, it is judged to be close to or equal to zero. If the deviation is greater than this positive number, the current operating mode 1 is maintained unchanged. In the above formula, v represents the cabin yaw rate, and ε represents the minimum threshold for stopping yaw, which is set to a very small positive number; Mode -1: The cabin yaw target angle is output at a constant rate, with the rate being negative. The system yaws counterclockwise to track the average wind direction until the deviation between the average wind direction and the cabin yaw target angle is close to or equal to zero. Then, the operating mode switches to Mode 2. A very small positive number is applied. If the deviation is less than this positive number, it is judged to be close to or equal to zero. If the deviation is greater than this positive number, the current operating mode -1 remains unchanged. Mode 2: When entering Mode 2, the cabin yaw target angle remains constant. A timer is initialized to zero and starts counting. If the timer exceeds the set yaw rest time threshold, the mode switches back to Mode 0. The purpose of Mode 2 is to ensure sufficient cool-down time before restarting the yaw action. In the above formula, Timer(t) represents a timer, and T0 represents a yaw rest time threshold.

7. The pitch-assisted yaw wind control method for a wind turbine according to claim 1, characterized in that: Based on the output cabin yaw target angle and compared with the cabin direction, the yaw drive torque is obtained through proportional and integral operations. The calculation formula of the yaw drive torque is as follows: In the above formula, t represents the time variable, M yaw (t) represents the yaw drive torque, k p represents the proportional gain of yaw to wind control, k i represents the yaw wind control integral gain, Indicates the cabin yaw target angle at the current moment, represents the cabin direction at the current moment, ∫(·)dt represents the integration operation over time; To generate a yaw drive torque on the wind rotor, it is necessary to apply different yaw pitch commands to the three blades. Since the thrust of each blade is different, a yaw drive torque is generated on the wind rotor plane. The yaw pitch command calculation formula for the three blades is as follows: In the above formula, Δβ 1,yaw represents the yaw pitch command of blade 1, Δβ 2,yaw represents the yaw pitch command of blade 2, Δβ 3,yaw Indicates the yaw pitch command of blade 3, H β represents the conversion coefficient from bending moment to pitch, θ A (t) represents the azimuth angle of blade 1, which is measured by the azimuth angle sensor, θ ph Indicates phase lead compensation.

8. The pitch-assisted yaw wind control method for a wind turbine according to claim 1, characterized in that: Based on the measured nacelle direction, the nacelle yaw rate is obtained through differential operation, and the yaw plus drag moment is obtained through proportional operation. The calculation formula of the yaw plus drag moment is as follows: In the above formula, M damper (t) represents the yaw drag moment, k damper Indicates the proportional gain of yaw resistance control, F damper (s) represents the yaw resistance low-pass filter, Indicates the differential operation of the cabin direction, Indicates the cabin direction at the current moment; To generate a yaw drag moment on the wind rotor, it is necessary to apply different yaw drag pitch commands to the three blades. Since the thrust of each blade is different, a yaw drag moment is generated on the wind rotor plane. The yaw drag pitch command calculation formula for the three blades is as follows: In the above formula, Δβ 1,damper represents the yaw resistance pitch control command of blade 1, Δβ 2,damper represents the yaw resistance pitch change command of blade 2, Δβ 3,damper Indicates the yaw resistance pitch control command of blade 3, H β represents the conversion coefficient from bending moment to pitch, θ A (t) represents the azimuth angle of blade 1, which is measured by the azimuth angle sensor, θ ph Indicates phase lead compensation.

9. The pitch-assisted yaw wind control method for a wind turbine according to claim 8, characterized in that: The calculation formula for the final pitch command is as follows: In the above formula, represents the final pitch command of blade 1, represents the final pitch command of blade 2, represents the final pitch command of blade 3, Δβ 1,yaw represents the yaw pitch command of blade 1, Δβ 2,yaw represents the yaw pitch command of blade 2, Δβ 3,yaw represents the yaw pitch command of blade 3, Δβ 1,damper represents the yaw resistance pitch control command of blade 1, Δβ 2,damper represents the yaw resistance pitch change command of blade 2, Δβ 3,damper represents the yaw resistance pitch control command of blade 3, β c Indicates unified pitch change command.

10. A variable pitch assisted yaw wind control system for a wind turbine, characterized in that: A method for implementing pitch-assisted yaw wind control of a wind turbine generator set according to any one of claims 1 to 9, comprising: The yaw trajectory planning module plans the optimal yaw trajectory based on the measured cabin direction and average wind direction, and outputs the cabin yaw target angle; The yaw-to-wind control module calculates the yaw pitch command for each blade based on the yaw target angle of the nacelle, which is used to generate a yaw torque on the rotor plane to push the nacelle to yaw, thereby achieving the purpose of the nacelle facing the wind; The yaw active drag module calculates the yaw drag pitch control command for each blade based on the actual yaw rate of the nacelle. This is used to control the yaw rate to be stable during the yawing process of the nacelle, so as to achieve the purpose of uniform yaw of the nacelle into the wind. The pitch command superposition module is used to superimpose the yaw pitch command of each blade with the yaw resistance pitch command, and then superimpose it with the unified pitch command given by the unit to obtain the final pitch command for each blade.

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