A method and system for yaw control of a fan

Abstract

The application relates to a fan yaw control method and system, and belongs to the technical field of wind turbine yaw systems. First, the instruction speed of a yaw motor and the actual speed of the yaw motor are acquired; when the instruction speed and the actual speed of the yaw motor are both 0, the input deviation of a speed loop is 0, the coefficient of integral accumulation in the speed loop of the yaw motor is less than 1, the integral control quantity is calculated according to the integral accumulation, the obtained integral control quantity result is assigned to the integral accumulation at the next moment, and when the integral accumulation is reduced to a certain threshold, the integral accumulation is cleared, the torque current of the speed loop is 0, and the static torque of the yaw motor is 0. The method can eliminate the static torque of the yaw motor without discharging the oil pressure of the brake system when the cabin is stopped.

Description

TECHNICAL FIELD

[0001] The application relates to a yaw control method and system of a wind turbine, and belongs to the technical field of yaw systems of wind turbines. BACKGROUND

[0002] The yaw system of a wind turbine, also known as a wind-aiming device, can drive a wind wheel to re-align with the wind direction to obtain maximum wind energy when the current wind speed direction changes. When the yaw system ends yawing, a yaw control system using vector control does not close the brake clutch of the yaw motor, and if the external wind load at this time is large, the cabin that has stopped yawing will move under the action of the wind load. The servo driver controls the output torque of the yaw motor to replace the braking torque of the yaw motor brake clutch to resist the action of the external wind load and make the cabin stop quickly without closing the brake clutch of the yaw motor. If the external wind load after the cabin stops yawing is not large, the actual speed of the cabin can be normally reduced to zero speed, and the yaw motor in a static state still outputs a static torque to resist the damping torque of the hydraulic brake system. At this time, the mechanical transmission gear of the yaw system is in a continuous force state, and the cabin will continuously emit noise due to force deformation.

[0003] When the cabin approaches the target yaw position, the servo driver starts to reduce the output of the torque current, controls the output torque of the yaw motor to decrease, and controls the cabin to perform deceleration motion at a certain deceleration until it enters a static state. Without considering the external wind load torque, the output torque of the yaw motor only needs to be reduced to approximately equal to the damping torque to make the cabin stop under the action of the mechanical friction torque. As long as the power (motor output torque) of the cabin yaw motion is not zero, the cabin will have a relative motion trend, and the existence of the relative motion trend causes the damping torque converted from the static friction torque to not automatically reduce to zero. Only when the cabin loses the power (the motor output torque becomes 0) and the relative motion trend, the damping torque can be automatically eliminated. However, since the yaw motor stops yawing, the speed command and the actual speed of the yaw motor are both 0, the speed loop input deviation e of the servo driver is 0, the speed loop cannot automatically eliminate the integral accumulation B0, the output of the speed loop cannot be zero, and the servo driver continuously controls the yaw motor to output a static torque. The existence of the static torque of the yaw motor makes the cabin always have a relative motion trend, and causes the damping torque converted from the static friction torque to not be automatically eliminated. At this time, the static torque output by the yaw motor is always in a state of resisting the damping torque, causing the cabin to be continuously stressed and thus continuously emit noise. In addition, since the servo driver continuously outputs current, the yaw motor is in a working state for a long time, causing serious heating.

[0004] When the yaw system is stopped and the nacelle is in a static state, the static torque output by the yaw motor and the damping torque output by the hydraulic brake system counteract each other. If the oil pressure of the hydraulic brake system is 0, the damping torque can be eliminated, and the static torque output by the yaw motor can also be eliminated. However, the hydraulic brake system must be in a full-pressure braking state when the yaw system is stopped, and this method cannot be used to solve the problem. If the servo driver is enabled to eliminate the static torque output by the yaw motor when the yaw system is stopped, the ability of the yaw motor to resist the torque of the external wind load will also be eliminated when the nacelle is displaced due to a sudden increase in the external wind load. SUMMARY

[0005] The purpose of the present application is to provide a wind turbine yaw control method and system to solve the problem that the static torque of the yaw motor cannot be eliminated when the nacelle is stopped, the damping torque cannot be eliminated, the nacelle emits noise, and the nacelle is seriously heated.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme.

[0007] The wind turbine yaw control method provided by the present application comprises the following steps.

[0008] 1) Obtain the command speed of the yaw motor and the actual speed of the yaw motor.

[0009] 2) When the command speed and the actual speed of the yaw motor are both 0, the input deviation of the speed loop is 0, the coefficient of the integral accumulation in the yaw motor speed loop is less than 1, the integral control quantity is calculated according to the integral accumulation, the current integral control quantity result is assigned to the integral accumulation at the next moment, and the integral accumulation is cleared when the integral accumulation is reduced to a certain threshold, so that the torque current of the speed loop is 0, and the static torque of the yaw motor is 0.

[0010] Beneficial effects: The wind turbine yaw control method provided by the present application can eliminate the static torque of the yaw motor by reducing the integral accumulation to a certain value or below and directly clearing the integral accumulation when the command speed and the actual speed of the yaw motor are both 0, according to the calculation relationship between the integral control quantity and the integral accumulation, and by continuously assigning the integral control quantity to the integral accumulation at the next moment, so that the integral accumulation is continuously reduced. Without the need to unload the oil pressure of the hydraulic brake system or to enable the yaw driver, the static torque is eliminated when the yaw system is stopped. The transmission gear of the nacelle yaw system is no longer continuously stressed, thereby prolonging the service life of the transmission gear. The nacelle no longer continuously emits noise due to continuous stress. After the integral accumulation is cleared, the torque current of the speed loop is also 0, rather than being maintained at a certain specific value. The yaw motor no longer generates serious heat due to long-time input of the current.

[0011] Further, the integral control quantity is:

[0012] B = μB0 + K i e

[0013] B0 is integral accumulation, K i is integral control coefficient, e is the input deviation of speed loop.

[0014] Beneficial effect: according to the formula of integral control quantity, integral control quantity and integral accumulation are linearly related, when the yaw stops, the coefficient of integral accumulation is less than 1, integral accumulation is equal to the result of the last integral control quantity, so integral accumulation gradually decreases, and then the static torque gradually decreases to zero, rather than directly clearing zero, so that the motion state and stress state of the cabin in the yaw stop moment are more smoothly and stably transitioned, and the vibration of the cabin in the stop moment is reduced.

[0015] Further, when the command speed of the yaw motor is not 0 or the actual speed is not 0, the coefficient of the integral accumulation in the speed loop of the yaw motor is equal to 1, and the yaw motor is controlled according to the output torque of the speed loop corresponding to the integral control quantity obtained at present.

[0016] Beneficial effect: when the cabin stops yawing and the external wind load suddenly increases, the actual speed of the yaw motor is not 0 at this time, so the input deviation of the speed loop is not zero, and the actual speed of the yaw motor is not 0 and automatically restores to 1 at this time, so that the coefficient of the integral accumulation is 1, the speed loop of the servo driver can start working normally again, and the output torque of the yaw motor can control the wind load to make the cabin return to the static state.

[0017] Further, the torque current of the speed loop is the sum of the proportional control quantity and the integral control quantity of the speed loop.

[0018] Beneficial effect: the torque current is the sum of the proportional control quantity and the integral control quantity of the speed loop, when the yaw stops, the proportional control quantity of the speed loop is 0, the integral control quantity is also 0, and then the torque current of the speed loop is also zero, rather than maintaining at a certain specific value, so that the yaw motor does not cause serious heating due to long-time input current.

[0019] Further, the proportional control quantity of the speed loop is the product of the proportional control coefficient and the input deviation.

[0020] The wind turbine yaw control system of the application comprises a processor, which is used to execute program instructions to realize the wind turbine yaw control method according to any one of the above.

[0021] Beneficial effects: The wind turbine yaw system of the present invention mainly includes a processor to execute program instructions to realize the wind turbine yaw control method. The system has a simple structure. When the yaw stops, without releasing the oil pressure of the hydraulic brake system or enabling the yaw drive, the static torque can be effectively eliminated. This prevents the transmission gears of the nacelle yaw system from being continuously stressed, thereby extending their service life. The nacelle also stops emitting noise due to continuous stress. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the working principle of the speed loop of the vector control system for static torque during yaw stop in the method embodiment of the present invention;

[0023] Figure 2 This is a flowchart illustrating the function of automatically eliminating electrostatic torque during yaw stop in an embodiment of the method of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings.

[0025] Example of wind turbine yaw control method:

[0026] like Figure 1 The method for eliminating static torque in a yaw system, as shown, first obtains the commanded speed and actual speed of the yaw motor. When the yaw motor is in a yaw-stopped state, the coefficient of the integral accumulator in the yaw motor speed loop is set to be less than 1. The integral control quantity is calculated based on the integral accumulator, and the obtained integral control quantity result is reassigned to the integral accumulator until the integral accumulator decreases to a certain threshold. Then, the integral accumulator is cleared to zero, making the torque current in the speed loop zero and the static torque of the yaw motor zero. The specific implementation is as follows:

[0027] like Figure 1 As shown, in the vector control algorithm of the servo driver, the input deviation of the speed loop is the commanded speed V of the yaw motor. cmd and the actual speed V of the yaw motor real The difference, i.e., e = V cmd -V real The speed loop output is the control command I for the driver's torque current (this current primarily controls the Q-axis current component of the output current). cmd The control command for the torque current is determined by the proportional control section and the integral control section of the speed loop, i.e., the sum of the proportional control quantity and the integral control quantity of the speed loop (A+B, where A is the proportional control quantity of the speed loop and B is the integral control quantity of the speed loop). The proportional control quantity A of the speed loop is:

[0028] A = K p *e

[0029] In the formula, K p This is the proportional control coefficient, which is a fixed value.

[0030] The integral control quantity B of the speed loop is:

[0031] B = μB0 + K i *e

[0032] In the formula, B0 is the integral cumulative quantity, whose initial value is 0, and K i *e is the integral scaling factor, K i This is the integral control coefficient. When the integral control quantity B is calculated, the result is assigned to the integral cumulative quantity B0, i.e., B0 = B.

[0033] like Figure 2 In the flowchart shown, when the main control system sends a command speed of 0 to the yaw motor of the servo driver, and the actual speed of the yaw motor is also 0, the yaw motor is currently in a yaw-stopped state, and the static torque elimination function of the servo driver is enabled. At this time, the input deviation of the speed loop is 0, and consequently, the proportional control quantity A of the speed loop is 0, and the integral control factor of the speed loop is 0, i.e., B = μB0. Then, the coefficient μ of the integral cumulative quantity B0 is set to <1. As the integral control quantity B, according to the command of the main control system, continuously assigns the current calculation result to the integral cumulative quantity B0 at the next moment, the integral control quantity B and the integral cumulative quantity B0 gradually decrease. At this time, the torque current control command I... cmd It also decreases accordingly, until the cumulative integral B0 decreases to a certain threshold B. min This directly resets the accumulated integral to zero, completely eliminating the static torque of the yaw motor. Among these, the threshold B... min This is not a constant value; it needs to be determined based on the specific model of the wind turbine and the on-site commissioning conditions. Generally, this threshold value B is used. min Set it to between 5% and 15% of the initial value of the accumulated points B0.

[0034] When the speed command sent by the main control system to the yaw motor of the servo driver is not 0, or the actual speed of the yaw motor is not 0, that is, the current yaw motor is in yaw motion state, the input deviation of the speed loop is not 0, and thus the proportional control quantity A is not 0. At this time, the integral proportional factor of the integral control quantity B is not 0. Let the coefficient μ of the integral cumulative quantity B0 be 1, and the yaw driver controls the yaw motor with the normal vector control process.

[0035] When the wind load outside the nacelle suddenly increases after the yawing motion of the nacelle stops, the yawing position (angle) of the nacelle changes under the action of the wind load outside the nacelle, and since the actual rotating speed of the yaw motor is not 0 at this time, the input deviation e of the speed loop is not 0, the actual rotating speed of the yaw motor is not 0 and is automatically restored to 1, so the static torque elimination function of the servo driver is automatically disabled, the speed loop of the servo driver can start to work normally again, and the yaw motor output torque controlled by the servo driver can resist the wind load to make the nacelle return to the static state again.

[0036] Embodiment of the wind turbine yaw control system:

[0037] The wind turbine yaw control system in the embodiment comprises a memory, a processor and an internal bus, the processor and the memory are in communication and data interaction with each other through the internal bus. The memory comprises at least one memory capable of storing the vector control algorithm of the servo driver, and the processor executes various function applications and data processing by running the software program and modules stored in the memory, so as to realize the wind turbine yaw control method introduced in the method embodiment of the application.

[0038] The processor can be a microprocessor MCU, a programmable logic device FPGA or other processing devices.

[0039] The memory can be various memories for storing information by using electric energy, such as RAM, ROM, etc.; various memories for storing information by using magnetic energy, such as hard disk, floppy disk, magnetic tape, magnetic core memory, bubble memory, U disk, etc.; various memories for storing information by using optical method, such as CD, DVD, etc.; of course, other memories can also be used, such as quantum memory, graphene memory, etc.

[0040] The above gives a specific embodiment, but the application is not limited to the described embodiment. The basic idea of the application is the above basic scheme, and according to the teaching of the application, various transformed models, formulas and parameters can be designed without creative labor. Changes, modifications, replacements and variations of the embodiment without departing from the principles and spirits of the application still fall within the protection scope of the application.

Claims

1. A wind turbine yaw control method, characterized by, The method comprises the following steps: 1) obtaining the command speed of the yaw motor and the actual speed of the yaw motor; 2) when the command speed and the actual speed of the yaw motor are both 0, the input deviation of the speed loop is 0, the coefficient of the integral accumulation in the speed loop of the yaw motor is less than 1, the integral control quantity is calculated according to the integral accumulation, the current integral control quantity is assigned to the integral accumulation at the next moment, and when the integral accumulation is reduced to a certain threshold, the integral accumulation is cleared, the torque current of the speed loop is 0, the static torque of the yaw motor is 0, the torque current is the sum of the proportional control quantity and the integral control quantity of the speed loop, and the integral control quantity is: B = μΒ0+ K i e B0 is the integral accumulation, K i is the integral control coefficient, and e is the input deviation of the speed loop.

2. The wind turbine yaw control method of claim 1, wherein The proportional control quantity of the speed loop is: A=K p *e In the formula, K p is a proportional control coefficient, and is a fixed value.

3. The wind turbine yaw control method of claim 2, wherein When the command speed or the actual speed of the yaw motor is not 0, the coefficient of the integral accumulation in the speed loop of the yaw motor is equal to 1, and the yaw motor is controlled according to the output torque of the speed loop corresponding to the current integral control quantity.

4. The wind turbine yaw control method of claim 1, wherein The threshold is between 5% and 15% of the initial value of the integral accumulation B0.

5. The wind turbine yaw control method of claim 2, wherein, The proportional control quantity of the speed loop is the product of the proportional control coefficient and the input deviation.

6. A wind turbine yaw control system comprising a processor, characterised in that, The processor is used to execute program instructions to realize the fan yaw control method according to any one of claims 1-5.

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