A Modular Control Method and System for Wind Turbines Based on Optimal Control

Abstract

The present invention discloses a modular control method and system for a wind turbine based on optimal control, which performs the following operations: Pitch power control: used for generator power control. When the wind speed is greater than a certain threshold, the wind turbine operates above the rated wind speed. The average power of the generator is adjusted to the rated power by changing the pitch angle, and the power fluctuation is within an acceptable range; Torque speed control: used for wind turbine speed control. When the wind speed is less than a certain threshold, the wind turbine operates below the rated wind speed. The speed of the wind turbine is adjusted below the rated speed by the generator torque, and the power output reaches the maximum. The present invention can achieve optimal control of power and speed.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine control, and in particular to a modular control method, system, storage medium and computing device for wind turbines based on optimal control. Background Art

[0002] In the process of converting wind energy into electrical energy, the control of wind turbines is particularly important. The wind energy utilization efficiency, stable output of electrical energy, stable wind turbine speed and the load of wind turbines during the energy conversion process are all determined by control. The traditional wind turbine control system uses proportional-integral control for pitch and generator torque, and does not establish a detailed control theory model. A single control method is difficult to achieve the optimal control effect. Therefore, a modular optimal control scheme needs to be proposed. Summary of the Invention

[0003] The first object of the present invention is to overcome the disadvantages and deficiencies of the prior art, and to provide a modular control method for wind turbines based on optimal control, which can achieve optimal control of power and speed.

[0004] The second object of the present invention is to provide a modular control system for wind turbines based on optimal control.

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

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

[0007] The first object of the present invention is achieved by the following technical solution: A modular control method for wind turbines based on optimal control, which performs the following operations:

[0008] Pitch power control: used for generator power control. When the wind speed is greater than a certain threshold, the wind turbine operates above the rated wind speed. The average power of the generator is adjusted to the rated power by adjusting the pitch angle, and the power fluctuation is within an acceptable range;

[0009] Torque speed control: used for wind turbine speed control. When the wind speed is less than a certain threshold, the wind turbine operates below the rated wind speed. The wind turbine speed is adjusted below the rated speed by adjusting the generator torque, and the power output reaches the maximum.

[0010] Furthermore, for the pitch power control, the pitch angle adjustment includes a power error adjustment term, a wind turbine acceleration compensation term, a feed-forward compensation term and a wind turbine imbalance compensation term. The unified pitch command has the following expression:

[0011]

[0012] In the above formula, Represents the unified pitch command; Represents the power error adjustment term; Represents the wind turbine acceleration compensation term; Represents the feed - forward compensation term; Represents the wind turbine imbalance compensation term; ∫dt represents the integral with respect to time;

[0013] The definition of the power error adjustment term is as follows:

[0014]

[0015] In the above formula, Represents the power error adjustment term; Represents the partial derivative of the wind turbine aerodynamic power with respect to pitch, and the superscript - 1 in the formula represents taking the reciprocal; γ p Represents the dynamic power control coefficient, used to control the amplitude of power fluctuations; Represents the first - order derivative of the generator power; Represents the first - order derivative of the generator reference power; ξ p Represents the damping ratio of the pitch power control; ω p Represents the cut - off frequency of the pitch power control; P e Represents the generator power; P e,ref Represents the generator reference power; ∫(P e -P e,ref )dt represents the integral of the generator power deviation;

[0016] The definition of the wind turbine acceleration compensation term is as follows:

[0017]

[0018] In the above formula, Represents the wind turbine acceleration compensation term; Represents the partial derivative of the wind turbine aerodynamic power with respect to pitch, and the superscript - 1 in the formula represents taking the reciprocal; J R Represents the equivalent moment of inertia of the wind turbine; Represents the second - order derivative of the wind turbine rotational speed; Represents the first - order derivative of the wind turbine rotational speed; ω r Represents the wind turbine rotational speed; ε R Represents the uncertainty of the wind turbine rotational speed; Represents the partial derivative of the wind turbine aerodynamic power with respect to the wind turbine rotational speed;

[0019] The feed - forward compensation term is defined as follows:

[0020]

[0021] In the above formula, Represents the feed - forward compensation term; Denotes the partial derivative of the wind turbine aerodynamic power with respect to pitch. The superscript -1 in the formula indicates taking the reciprocal. Denotes the partial derivative of the wind turbine aerodynamic power with respect to wind speed; Denotes the first derivative of wind speed; Denotes the first partial derivative of the tower top front - rear speed;

[0022] The wind turbine imbalance compensation term is defined as follows:

[0023]

[0024] In the above formula, Denotes the wind turbine imbalance compensation term; Denotes the partial derivative of the wind turbine aerodynamic power with respect to pitch. The superscript -1 in the formula indicates taking the reciprocal; Denotes the first derivative of the additional pitch angle of blade i; Denotes the sum of the first derivatives of the additional pitch angles of all blades; Denotes the partial derivative of the wind turbine aerodynamic power with respect to wind speed; Denotes the first derivative of the additional wind speed of blade i; Denotes the sum of the first derivatives of the additional wind speeds of all blades.

[0025] Furthermore, for torque - speed control, the generator torque regulation includes a speed error regulation term, a speed bias compensation term, and a feed - forward compensation term. The generator torque command has the following expression:

[0026]

[0027] In the above formula, Denotes the generator torque command; Denotes the speed error regulation term; Denotes the speed bias compensation term; Denotes the feed - forward compensation term; ∫dt represents the integration with respect to time;

[0028] The definition of the speed error regulation term is as follows:

[0029]

[0030] In the above formula, Denotes the speed error regulation term; J R Denotes the equivalent moment of inertia of the wind turbine; N represents the gearbox transmission ratio; γ s Denotes the dynamic speed control coefficient, which is used to control the amplitude of speed fluctuations; Denotes the second derivative of the wind turbine speed; Denotes the second derivative of the wind turbine speed reference value; ξ s Denotes the damping ratio of torque - speed control; ω sRepresents the cut-off frequency of torque and speed control; Represents the first derivative of the wind turbine speed; Represents the first derivative of the reference value of the wind turbine speed; ω r Represents the wind turbine speed; ω r,ref Represents the reference value of the wind turbine speed;

[0031] The definition of the speed offset compensation term is as follows:

[0032]

[0033] In the above formula, Represents the speed offset compensation term; N represents the gearbox transmission ratio; T a Represents the aerodynamic torque of the wind turbine; Represents the partial derivative of the aerodynamic torque of the wind turbine with respect to the pitch angle; Represents the first derivative of the pitch angle;

[0034] The definition of the feedforward compensation term is as follows:

[0035]

[0036] In the above formula, Represents the feedforward compensation term; N represents the gearbox transmission ratio; Represents the partial derivative of the aerodynamic torque of the wind turbine with respect to the wind turbine speed; ε R Represents the uncertainty of the wind turbine speed; Represents the first derivative of the wind turbine speed; Represents the partial derivative of the aerodynamic torque of the wind turbine with respect to the wind speed; Represents the first derivative of the wind speed; Represents the first partial derivative of the front and rear speeds of the tower top.

[0037] The second object of the present invention is achieved by the following technical solution: A modular control system for a wind turbine based on optimal control, used to implement the modular control method for a wind turbine based on optimal control as described above, which includes:

[0038] A pitch power control module, used for generator power control. When the wind speed is greater than a certain threshold, the wind turbine operates above the rated wind speed, and the average power of the generator is adjusted to the rated power by the pitch angle, and the power fluctuation is within an acceptable range;

[0039] A torque and speed control module, used for wind turbine speed control. When the wind speed is less than a certain threshold, the wind turbine operates below the rated wind speed, and the wind turbine speed is adjusted below the rated speed by the generator torque, and the power output reaches the maximum.

[0040] The third objective of the present invention is achieved through the following technical solution: A storage medium stores a program, which, when executed by a processor, implements the above-mentioned modular control method for a wind turbine based on optimal control.

[0041] The fourth objective of the present invention is achieved through the following technical solution: A computing device includes a processor and a memory for storing programs executable by the processor. When the processor executes the programs stored in the memory, it implements the above-mentioned modular control method for a wind turbine based on optimal control.

[0042] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0043] 1. The pitch power control proposed by the present invention takes into account power error regulation, wind turbine acceleration compensation, feed-forward compensation, and wind turbine imbalance compensation. By constructing a detailed control model, optimal control of power is achieved.

[0044] 2. The torque speed control proposed by the present invention takes into account speed error regulation, speed bias compensation, and feed-forward compensation. By constructing a detailed control model, optimal control of speed is achieved.

[0045] 3. The present invention constructs each control module in a modular manner, making the logical structure of the control system clear and having good scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is the architecture diagram of the system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0048] Embodiment 1

[0049] This embodiment discloses a modular control method for a wind turbine based on optimal control, which performs the following operations:

[0050] Pitch power control: For generator power control, when the wind speed is high enough, the wind turbine operates above the rated wind speed. The average power of the generator is adjusted to the rated power by adjusting the pitch angle, and the power fluctuation is within an acceptable range. Among them, the pitch angle adjustment includes a power error adjustment term, a wind turbine acceleration compensation term, a feed-forward compensation term, and a wind turbine imbalance compensation term. The unified pitch command has the following expression:

[0051]

[0052] In the above formula, represents the unified pitch command; represents the power error adjustment term; Represents the wind turbine acceleration compensation term; Represents the feed-forward compensation term; Represents the wind turbine imbalance compensation term; ∫dt represents the integration with respect to time;

[0053] The definition of the power error adjustment term is as follows:

[0054]

[0055] In the above formula, Represents the power error adjustment term; Represents the partial derivative of the wind turbine aerodynamic power with respect to pitch; the superscript -1 in the formula represents taking the reciprocal; γ p Represents the dynamic power control coefficient, used to control the amplitude of power fluctuations; Represents the first derivative of the generator power; Represents the first derivative of the generator reference power; ξ p Represents the damping ratio of the pitch power control; ω p Represents the cut-off frequency of the pitch power control; P e Represents the generator power; P e,ref Represents the generator reference power; ∫(P e -P e,ref )dt represents the integration of the generator power deviation;

[0056] The definition of the wind turbine acceleration compensation term is as follows:

[0057]

[0058] In the above formula, Represents the wind turbine acceleration compensation term; Represents the partial derivative of the wind turbine aerodynamic power with respect to pitch; the superscript -1 in the formula represents taking the reciprocal; J R Represents the equivalent moment of inertia of the wind turbine; Represents the second derivative of the wind turbine rotational speed; Represents the first derivative of the wind turbine rotational speed; ω r Represents the wind turbine rotational speed; ε R Represents the uncertainty of the wind turbine rotational speed; Represents the partial derivative of the wind turbine aerodynamic power with respect to the wind turbine rotational speed;

[0059] The feed-forward compensation term is defined as follows:

[0060]

[0061] In the above formula, Represents the feed-forward compensation term; Represents the partial derivative of the wind turbine aerodynamic power with respect to pitch; the superscript -1 in the formula represents taking the reciprocal; represents the partial derivative of the wind turbine aerodynamic power with respect to the wind speed; represents the first derivative of the wind speed; represents the first partial derivative of the tower top front and rear speeds;

[0062] The wind turbine imbalance compensation term is defined as follows:

[0063]

[0064] In the above formula, represents the wind turbine imbalance compensation term; represents the partial derivative of the wind turbine aerodynamic power with respect to the pitch angle. The superscript -1 in the formula indicates taking the reciprocal; represents the first derivative of the additional pitch angle of blade i; represents the sum of the first derivatives of the additional pitch angles of all blades; represents the partial derivative of the wind turbine aerodynamic power with respect to the wind speed; represents the first derivative of the additional wind speed of blade i; represents the sum of the first derivatives of the additional wind speeds of all blades.

[0065] Torque and speed control: Used for wind turbine speed control. When the wind speed is low, the wind turbine operates below the rated wind speed. The wind turbine speed is adjusted below the rated speed through the generator torque, and the power output reaches the maximum. Among them, the generator torque adjustment includes a speed error adjustment term, a speed bias compensation term, and a feedforward compensation term. The generator torque command has the following expression:

[0066]

[0067] In the above formula, represents the generator torque command; represents the speed error adjustment term; represents the speed bias compensation term; represents the feedforward compensation term; ∫dt represents the integral with respect to time;

[0068] The definition of the speed error adjustment term is as follows:

[0069]

[0070] In the above formula, represents the speed error adjustment term; J R represents the equivalent moment of inertia of the wind turbine; N represents the gearbox transmission ratio; γ s represents the dynamic speed control coefficient, used to control the amplitude of speed fluctuations; represents the second derivative of the wind turbine speed; represents the second derivative of the wind turbine speed reference value; ξ srepresents the damping ratio of torque - speed control; ω s represents the cut - off frequency of torque - speed control; represents the first - order derivative of the wind turbine speed; represents the first - order derivative of the reference value of the wind turbine speed; ω r represents the wind turbine speed; ω r,ref represents the reference value of the wind turbine speed;

[0071] The definition of the rotational speed bias compensation term is as follows:

[0072]

[0073] In the above formula, represents the rotational speed bias compensation term; N represents the gearbox transmission ratio; T a represents the aerodynamic torque of the wind turbine; represents the partial derivative of the aerodynamic torque of the wind turbine with respect to the pitch angle; represents the first - order derivative of the pitch angle;

[0074] The definition of the feed - forward compensation term is as follows:

[0075]

[0076] In the above formula, represents the feed - forward compensation term; N represents the gearbox transmission ratio; represents the partial derivative of the aerodynamic torque of the wind turbine with respect to the wind turbine speed; ε R represents the uncertainty of the wind turbine speed; represents the first - order derivative of the wind turbine speed; represents the partial derivative of the aerodynamic torque of the wind turbine with respect to the wind speed; represents the first - order derivative of the wind speed; represents the first - order partial derivative of the front - and - rear speed at the top of the tower.

[0077] Embodiment 2

[0078] This embodiment discloses a modular control system for a wind turbine based on optimal control, which is used to implement the modular control method for a wind turbine based on optimal control described in Embodiment 1, as Figure 1 shown, the system includes the following functional modules:

[0079] The pitch - power control module is used for generator power control, with the pitch - angle command as the input variable and the generator power as the output variable; when the wind speed is greater than a certain threshold, the wind turbine operates above the rated wind speed, and the generator average power is adjusted to the rated power through the pitch angle, and the power fluctuation is within an acceptable range;

[0080] The torque and speed control module is used for controlling the wind turbine speed. The generator torque command serves as the input variable, and the wind turbine speed serves as the output variable. When the wind speed is less than a certain threshold, the wind turbine operates below the rated wind speed. The wind turbine speed is adjusted below the rated speed by the generator torque, and the power output reaches the maximum.

[0081] Embodiment 3

[0082] This embodiment discloses a storage medium storing a program, which, when executed by a processor, implements the modular control method for a wind turbine based on optimal control described in Embodiment 1.

[0083] The storage medium in this embodiment can be a magnetic 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 such media.

[0084] Embodiment 4

[0085] 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, it implements the modular control method for a wind turbine based on optimal control described in Embodiment 1.

[0086] The computing device described in this embodiment can 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 processor functions.

[0087] The above embodiments are preferred embodiments of the present invention. However, the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A modular control method for a wind turbine based on optimal control, characterized in that, Perform the following operations: Pitch power control: Used for generator power control. When the wind speed is greater than a certain threshold, the wind turbine operates above the rated wind speed. The average power of the generator is adjusted to the rated power by adjusting the pitch angle, and the power fluctuation is within an acceptable range; Torque and speed control: Used for wind turbine speed control. When the wind speed is less than a certain threshold, the wind turbine operates below the rated wind speed. The speed of the wind turbine is adjusted below the rated speed by adjusting the generator torque, and the power output reaches the maximum; For pitch power control, the pitch angle adjustment includes a power error adjustment term, a wind turbine acceleration compensation term, a feed-forward compensation term, and a wind turbine imbalance compensation term. The unified pitch command has the following expression: In the above formula, represents the unified pitch command; represents the power error adjustment term; represents the wind turbine acceleration compensation term; represents the feed-forward compensation term; represents the wind turbine imbalance compensation term; ∫dt represents the integration with respect to time; The definition of the power error adjustment term is as follows: In the above formula, represents the power error adjustment term; represents the partial derivative of the aerodynamic power of the wind turbine with respect to pitch. The superscript -1 in the formula indicates taking the reciprocal; γ p represents the dynamic power control coefficient, which is used to control the amplitude of power fluctuations; represents the first derivative of the generator power; represents the first derivative of the generator reference power; ξ p represents the damping ratio of the pitch power control; ω p represents the cut-off frequency of the pitch power control; P e represents the generator power; P e,ref represents the generator reference power; ∫(P e -P e,ref )dt represents the integral of the generator power deviation; The definition of the wind turbine acceleration compensation term is as follows: In the above formula, represents the wind turbine acceleration compensation term; represents the partial derivative of the wind turbine aerodynamic power with respect to the pitch. The superscript -1 in the formula indicates taking the reciprocal; J R represents the equivalent moment of inertia of the wind turbine; represents the second derivative of the wind turbine rotational speed; represents the first derivative of the wind turbine rotational speed; ω r represents the wind turbine rotational speed; ε R represents the uncertainty of the wind turbine rotational speed; represents the partial derivative of the wind turbine aerodynamic power with respect to the wind turbine rotational speed; The definition of the feed-forward compensation term is as follows: In the above formula, represents the feedforward compensation term; represents the partial derivative of the aerodynamic power of the wind turbine with respect to pitch, and the superscript -1 in the formula indicates taking the reciprocal; represents the partial derivative of the aerodynamic power of the wind turbine with respect to wind speed; represents the first derivative of wind speed; represents the first partial derivative of the velocities before and after the tower top; The definition of the wind turbine imbalance compensation term is as follows: In the above formula, represents the wind turbine imbalance compensation term; represents the partial derivative of the wind turbine aerodynamic power with respect to pitch, and the superscript -1 in the formula indicates taking the reciprocal; represents the first derivative of the additional pitch angle of blade i; represents the sum of the first derivatives of the additional pitch angles of all blades; represents the partial derivative of the wind turbine aerodynamic power with respect to wind speed; represents the first derivative of the additional wind speed of blade i; represents the sum of the first derivatives of the additional wind speeds of all blades.

2. The modular control method for a wind turbine based on optimal control according to claim 1, characterized in that, For torque and speed control, the generator torque adjustment includes a speed error adjustment term, a speed bias compensation term, and a feed-forward compensation term. The generator torque command has the following expression: In the above formula, represents the generator torque command; represents the rotational speed error adjustment term; represents the rotational speed bias compensation term; represents the feedforward compensation term; ∫dt represents the integration with respect to time; The definition of the speed error adjustment term is as follows: In the above formula, represents the rotational speed error regulation term; J R represents the equivalent moment of inertia of the wind turbine rotor; N represents the gearbox transmission ratio; γ s represents the dynamic rotational speed control coefficient, which is used to control the amplitude of rotational speed fluctuations; represents the second derivative of the wind turbine rotor speed; represents the second derivative of the reference value of the wind turbine rotor speed; ξ s represents the damping ratio of torque-rotational speed control; ω s represents the cut-off frequency of torque-rotational speed control; represents the first derivative of the wind turbine rotor speed; represents the first derivative of the reference value of the wind turbine rotor speed; ω r represents the wind turbine rotor speed; ω r,ref represents the reference value of the wind turbine rotor speed; The definition of the speed bias compensation term is as follows: In the above formula, represents the rotational speed offset compensation term; N represents the gearbox transmission ratio; T a represents the aerodynamic torque of the wind turbine; represents the partial derivative of the aerodynamic torque of the wind turbine with respect to the pitch angle; represents the first derivative of the pitch angle; The definition of the feed-forward compensation term is as follows: In the above formula, represents the feedforward compensation term; N represents the gearbox transmission ratio; represents the partial derivative of the wind turbine aerodynamic torque with respect to the wind turbine rotational speed; ε R represents the uncertainty of the wind turbine rotational speed; represents the first derivative of the wind turbine rotational speed; represents the partial derivative of the wind turbine aerodynamic torque with respect to the wind speed; represents the first derivative of the wind speed; represents the first partial derivative of the front and rear speeds at the tower top.

3. A modular control system for a wind turbine based on optimal control, characterized in that, Used to implement the modular control method of a wind turbine based on optimal control as described in claim 1 or 2, which includes: A pitch power control module, used for generator power control. When the wind speed is greater than a certain threshold, the wind turbine operates above the rated wind speed. The average power of the generator is adjusted to the rated power by adjusting the pitch angle, and the power fluctuation is within an acceptable range; A torque and speed control module, used for wind turbine speed control. When the wind speed is less than a certain threshold, the wind turbine operates below the rated wind speed. The speed of the wind turbine is adjusted below the rated speed by adjusting the generator torque, and the power output reaches the maximum.

4. A storage medium storing a program, characterized in that,When the program is executed by a processor, the modular control method of a wind turbine based on optimal control as described in claim 1 or 2 is implemented.

5. A computing device, comprising a processor and a memory for storing processor-executable programs, characterized in that, When the processor executes the program stored in the memory, the modular control method of a wind turbine based on optimal control as described in claim 1 or 2 is implemented.

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