A self-disturbance all-wind-speed power smoothing method based on fan rotor kinetic energy

Abstract

The application provides a self-disturbance-rejection full-wind-speed power smoothing method based on wind turbine rotor kinetic energy, and belongs to the technical field of wind power control. The technical scheme is as follows: S1: based on a wind turbine dynamics model, rotor kinetic energy is calculated and its role in power fluctuation suppression is analyzed; S2: a first-order linear active disturbance rejection controller is designed for speed loop control; S3: a second-order linear active disturbance rejection controller is designed for variable pitch control; S4: active power reference is dynamically generated by combining rotor kinetic energy and active disturbance rejection control technology, and speed loop and variable pitch control are coordinated. The application has the beneficial effects that the application can significantly reduce power fluctuation under wind speed fluctuation and complex working conditions, improve the smoothness of power output, enhance the anti-interference ability and dynamic stability of the system, and ensure the efficient and stable operation of the wind power generator system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power control, and particularly relates to a self-disturbance all-wind-speed power smoothing method based on wind turbine rotor kinetic energy. BACKGROUND

[0002] In recent years, wind power has been rapidly developed and widely applied as a clean and renewable energy form. However, large-scale grid connection of wind energy still faces many technical challenges, of which the most important limiting factor is that wind energy itself has characteristics such as randomness, intermittency and unpredictability. These characteristics cause the output power of wind turbine generators to frequently fluctuate with the change of wind speed. If these fluctuating powers are directly connected to the power grid, it will have a significant impact on the frequency stability, voltage quality and overall operation reliability of the power grid. With the increasing proportion of wind power in the power grid year by year, this problem has become increasingly prominent and has become a key bottleneck restricting large-scale grid connection of wind power. To address this challenge, it is obvious that in order to meet the grid connection standards and improve the grid-connected power quality of the wind power system, effective technical means must be taken to smooth the output power of the wind turbine generator as much as possible, so as to ensure the stability of the power grid operation. Therefore, smoothing the output power has become a core problem that needs to be solved for large-scale grid connection of wind power.

[0003] At present, the research on wind turbine output power smoothing control at home and abroad mainly focuses on two categories: indirect power control and direct power control. Among them, the direct power control method does not need to add additional energy storage devices, and its core idea is to optimize the control of the pitch angle and generator speed of the wind turbine, and use the power regulation capability of the wind turbine itself to suppress the output power fluctuation. The direct power control method mainly includes the following three methods: using the inertia kinetic energy storage of the wind turbine itself: by adjusting the rotor speed, the wind energy is converted into rotor kinetic energy storage or release, so as to smooth the output power. This method makes full use of the rotational inertia of the wind turbine, has the advantages of fast response speed and no need for additional equipment; using variable pitch control: by adjusting the pitch angle to change the wind energy capture efficiency, the output power is indirectly adjusted. This method can effectively cope with sudden changes in wind speed, but frequent pitch changes may cause fatigue damage to mechanical parts; using direct voltage control: by adjusting the direct voltage to balance the power fluctuation. This method is suitable for variable frequency converter control, but may cause large fluctuations in the direct voltage, affecting the stability of the system. Among the above methods, the method of using the inertia kinetic energy storage of the wind turbine itself has obvious advantages. Compared with other methods, it avoids the mechanical stress problem caused by frequent pitch changes, and also reduces the risk of excessive fluctuation of the direct voltage. However, this method also has certain limitations: due to the limited rotational inertia of the wind turbine, the kinetic energy that can be stored is also limited, resulting in insufficient power smoothing capability, especially under conditions of severe wind speed fluctuations or long-term low wind speed, the adjustment effect is significantly reduced.

[0004] How to solve the above technical problems, the technical problems solved by the present application. SUMMARY

[0005] The purpose of the present application is to provide a self-disturbance full wind speed power smoothing method based on wind turbine rotor kinetic energy, which introduces multiple self-disturbance control technology on the basis of traditional direct power smoothing control method based on kinetic energy storage, optimizes the speed ring control through first-order linear self-disturbance controller, and optimizes the variable pitch control through second-order linear self-disturbance controller, realizes the efficient smoothing control of wind turbine output power, and through the organic combination of rotor kinetic energy and self-disturbance control technology, the present application not only significantly improves the smoothness of power output, but also enhances the anti-interference ability and dynamic stability of the system, providing an efficient and reliable solution for large-scale grid connection of wind power generation.

[0006] In order to realize the above-mentioned application purpose, the technical scheme adopted by the present application is as follows: a self-disturbance full wind speed power smoothing method based on wind turbine rotor kinetic energy, comprising the following steps:

[0007] S1: based on the wind turbine dynamics model, calculate the rotor kinetic energy and analyze its role in power fluctuation suppression, combine the wind turbine operating characteristics, and derive the energy regulation ability of rotor kinetic energy under different wind speed conditions;

[0008] S2: design a first-order linear self-disturbance controller for speed ring control, estimate the total disturbance of the system in real time through the extended state observer, and dynamically adjust the speed based on the first-order linear control law, to improve the dynamic response speed and anti-interference ability of the speed ring;

[0009] S3: design a second-order linear self-disturbance controller for variable pitch control, optimize the dynamic adjustment performance of variable pitch through high-order disturbance estimation and compensation, and ensure the power output smoothness of wind turbine under wind speed mutation or external disturbance;

[0010] S4: combine rotor kinetic energy and self-disturbance control technology to dynamically generate active power reference value, and realize efficient smoothing control of power output through coordination of speed ring and variable pitch control.

[0011] Further, in the step S1, the mechanical power of the wind turbine is :

[0012] (1)

[0013] In formula (1), is the air density, is the wind turbine blade radius, is the wind speed, is the wind energy utilization coefficient, is the tip speed ratio, is the pitch angle, is the wind speed variation rate influence coefficient. Tip speed ratio The expression is:

[0014] (2)

[0015] In equation (2), is the rotor angular velocity.

[0016] The rotor kinetic energy of the wind turbine is:

[0017] (3)

[0018] In equation (3), is the moment of inertia.

[0019] The rate of change of rotor kinetic energy and the mechanical power of the wind turbine and the generator output power The relationship is:

[0020] (4)

[0021] In equation (4), is the power variation rate damping coefficient.

[0022] By adjusting the rotor speed, the rotor kinetic energy can be used as an energy buffer to smooth the full wind speed power output. At low wind speed, the mechanical power is small, and the adjustment ability of the rotor kinetic energy is limited, mainly used to smooth small amplitude power fluctuations; at medium wind speed, the mechanical power is large, and the adjustment ability of the rotor kinetic energy is significantly enhanced, which can effectively suppress the power fluctuations caused by wind speed fluctuations; at high wind speed, the mechanical power is close to the rated value, and the adjustment ability of the rotor kinetic energy is mainly used to cope with wind speed mutations to prevent power overlimiting.

[0023] Further, in the step S2, the first-order linear active disturbance rejection controller estimates the total disturbance of the system in real time through the extended state observer, including wind speed fluctuations, mechanical losses and external disturbances, and the disturbance estimation formula is:

[0024] (5)

[0025] In equation (5), is the system state estimate, is the disturbance estimate, is the rotor speed state estimation gain, is the rotor speed input gain, is the total disturbance estimation gain of the system, is the system output, is the control input, respectively, derivative of

[0026] based on the disturbance estimation value , the control law is designed as :

[0027] (6)

[0028] In formula (6), is the reference input, is the speed loop proportional control gain, is the disturbance estimation gain, is the speed loop integral control gain, is the speed loop derivative control gain, the integral term is used to eliminate the steady-state error, and the derivative term is used to improve the dynamic response speed;

[0029] The first-order linear active disturbance rejection controller adjusts the rotor speed dynamically , so that the speed loop quickly recovers to stable state under wind speed fluctuation and external disturbance, and the dynamic equation of the speed loop is:

[0030] (7)

[0031] In formula (7), is the disturbance torque, is the derivative of .

[0032] Further, in the step S3, the second-order linear active disturbance rejection controller estimates the total disturbance of the system and its rate of change in real time through a high-order extended state observer, and the disturbance estimation formula is:

[0033] (8)

[0034] In formula (8), is the system state estimation value, is the disturbance estimation value, is the disturbance rate estimation value, is the pitch angle state estimation gain, is the pitch angle input gain, is the system disturbance gain, is the system disturbance rate gain, respectively, derivative of

[0035] Based on the disturbance estimation value and the disturbance rate estimation value , the control law is designed as is:

[0036] (9)

[0037] In formula (9), is a pitch angle proportional control gain, is a disturbance estimation gain, is a disturbance rate estimation gain, is a pitch angle integral control gain, is a pitch angle differential control gain;

[0038] The pitch angle is dynamically adjusted by a second-order linear active disturbance rejection controller , so as to ensure the smoothness of power output of the wind turbine under wind speed mutation or external disturbance, and the dynamic equation of the pitch angle is:

[0039] (10)

[0040] In formula (10), is a pitch angle reference value, is a time constant, is a derivative of . The integral term is used to further smooth the pitch angle change.

[0041] Further, in the step S4, the rotor kinetic energy and the active disturbance rejection control technology are combined to generate an active reference value is:

[0042] (11)

[0043] In formula (11), is an integral gain coefficient.

[0044] The speed loop is adjusted by a first-order linear active disturbance rejection controller, and the pitch angle is adjusted by a second-order linear active disturbance rejection controller, so as to realize efficient and smooth control of the power output in the whole wind speed. Under wind speed fluctuation and external disturbance, the smoothness of the power output and the stable operation of the system are ensured by dynamically adjusting the speed and the pitch angle.

[0045] Compared with the prior art, the beneficial effects of the present application are:

[0046] 1. The present application discloses a wind turbine rotor kinetic energy-based active disturbance rejection whole wind speed power smoothing method, which combines the rotor kinetic energy with the active disturbance rejection control technology to realize efficient and smooth control of the wind turbine output power. Moreover, the present application can significantly reduce power fluctuation under wind speed fluctuation and complex working conditions, improve the smoothness of power output, enhance the anti-interference ability and dynamic stability of the system, and ensure efficient and stable operation of the wind turbine system.

[0047] 2, The application uses the rotor kinetic energy of the fan as a power buffer carrier to build an energy regulation mechanism based on the dynamic characteristics of the rotor. Traditional methods usually rely on external energy storage devices or sacrifice power generation efficiency to suppress power fluctuations, while the application uses the rotor kinetic energy of the fan to maintain smooth electromagnetic power output. This innovation enables the system to reduce power fluctuation amplitude without increasing hardware costs, significantly improving power smoothing effect in the region below the rated wind speed. Tests show that in turbulent wind conditions, the output power smoothing degree is improved by 15% compared to traditional PSF control.

[0048] 3, The application adopts a collaborative architecture of first-order and second-order linear active disturbance rejection control, solving the technical problem of strong coupling between the speed ring and the variable pitch ring in traditional control. The simplified first-order LADRC designed for the speed ring estimates and compensates disturbances in real time through an extended state observer, improving system dynamic response; the second-order LADRC designed for the variable pitch system effectively suppresses mechanical resonance problems during pitch angle adjustment. This hierarchical control structure can maintain rated power output in turbulent conditions at high wind speeds compared to existing unified control strategies. Meanwhile, the application reduces the controller debugging parameters from 5 to 2 through linearization parameter setting method, maintaining the anti-disturbance performance of nonlinear control and greatly reducing the engineering implementation difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0049] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, which together with the embodiments of the application, serve to explain the application, and do not constitute a limitation of the application.

[0050] Figure 1 The simulation diagram for low wind speed region turbulence in the embodiment 2 of the application is shown.

[0051] Figure 2 The power output comparison chart when the low wind speed region turbulence in the embodiment 2 of the application is shown.

[0052] Figure 3 The simulation diagram for high wind speed region turbulence in the embodiment 3 of the application is shown.

[0053] Figure 4 The power output comparison chart when the high wind speed region turbulence in the embodiment 3 of the application is shown.

[0054] Figure 5 The first-order linear active disturbance rejection speed ring vector control block diagram based on rotor kinetic energy in the application is shown.

[0055] Figure 6 The second-order linear active disturbance rejection pitch control block diagram in the application is shown. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. Of course, the specific examples described herein are only used to explain the present application and not to limit the present application.

[0057] Example 1: see Figure 1 、 Figure 2 、 Figure 5 、 Figure 6 The technical scheme of the present embodiment is a self-disturbance full-wind-speed power smoothing method based on fan rotor kinetic energy, which comprises the following steps:

[0058] S1: Based on the fan dynamics model, the rotor kinetic energy is calculated and its role in power fluctuation suppression is analyzed. Combined with the fan operating characteristics, the energy regulation ability of the rotor kinetic energy under different wind speed conditions is derived;

[0059] S2: A first-order linear active disturbance rejection controller is designed for speed loop control. The total disturbance of the system is estimated in real time through the extended state observer, and the speed is dynamically adjusted based on the first-order linear control law to improve the dynamic response speed and anti-interference ability of the speed loop;

[0060] S3: A second-order linear active disturbance rejection controller is designed for variable pitch control. Through high-order disturbance estimation and compensation, the dynamic adjustment performance of variable pitch is optimized to ensure the power output smoothness of the fan under wind speed mutation or external disturbance;

[0061] S4: Combine rotor kinetic energy with active disturbance rejection control technology to dynamically generate active power reference value. Through coordination of speed loop and variable pitch control, efficient smooth control of power output is realized.

[0062] In step S1, the mechanical power of the fan is:

[0063] (1)

[0064] In formula (1), is the air density, is the fan blade radius, is the wind speed, is the wind energy utilization coefficient, is the tip speed ratio, is the pitch angle, is the wind speed change rate influence coefficient, and the tip speed ratio is expressed as:

[0065] (2)

[0066] In formula (2), is the rotor angular velocity.

[0067] Kinetic energy of fan rotor is:

[0068] (3)

[0069] In formula (3), is the moment of inertia.

[0070] The rate of change of rotor kinetic energy and the mechanical power of the fan and the generator output power is:

[0071] (4)

[0072] In formula (4), is the power change rate damping coefficient.

[0073] By adjusting the rotor speed, the rotor kinetic energy can be used as an energy buffer to smooth the full wind speed power output. Under low wind speed conditions, the mechanical power is small, and the adjustment capability of the rotor kinetic energy is limited, mainly used to smooth small amplitude power fluctuations; under medium wind speed conditions, the mechanical power is large, and the adjustment capability of the rotor kinetic energy is significantly enhanced, which can effectively suppress the power fluctuations caused by wind speed fluctuations; under high wind speed conditions, the mechanical power is close to the rated value, and the adjustment capability of the rotor kinetic energy is mainly used to cope with wind speed mutations and prevent power overruns.

[0074] In step S2, the first-order linear active disturbance rejection controller estimates the total disturbance of the system in real time through the extended state observer, including wind speed fluctuations, mechanical losses and external disturbances, and the disturbance estimation formula is:

[0075] (5)

[0076] In formula (5), is the system state estimate, is the disturbance estimate, is the speed state estimation gain, is the speed input gain, is the total disturbance estimation gain of the system, is the system output, is the control input, are the derivatives of respectively;

[0077] Based on the disturbance estimate , the control law is designed as:

[0078] (6)

[0079] In formula (6), is a reference input, is a speed loop proportional control gain, is a disturbance estimation gain, is a speed loop integral control gain, is a speed loop derivative control gain, the integral term is used to eliminate steady-state error, and the derivative term is used to improve dynamic response speed;

[0080] The first-order linear active disturbance rejection controller adjusts the rotor speed dynamically to make the speed loop quickly recover to stability under wind speed fluctuation and external disturbance, and the speed loop dynamic equation is:

[0081] (7)

[0082] In formula (7), is a disturbance torque, is a derivative.

[0083] In step S3, the second-order linear active disturbance rejection controller estimates the total disturbance of the system and its rate of change in real time through a high-order extended state observer, and the disturbance estimation formula is:

[0084] (8)

[0085] In formula (8), is a system state estimation value, is a disturbance estimation value, is a disturbance rate estimation value, is a pitch angle state estimation gain, is a pitch angle input gain, is a system disturbance gain, is a system disturbance rate gain, is a derivative of , respectively;

[0086] Based on the disturbance estimation value and the disturbance rate estimation value , the control law is designed as:

[0087] (9)

[0088] In formula (9), is a pitch angle proportional control gain, is a disturbance estimation gain, is a disturbance rate estimation gain, a pitch angle integral control gain, a pitch angle differential control gain;

[0089] a pitch angle by a second-order linear active disturbance rejection controller , to ensure the smoothness of the power output of the wind turbine under wind speed mutation or external disturbance, the pitch angle dynamic equation is:

[0090] (10)

[0091] In formula (10), is a pitch angle reference value, is a time constant, is the derivative of . The integral term is used to further smooth the pitch angle change.

[0092] In step S4, the rotor kinetic energy and the active disturbance rejection control technology are combined to generate the active reference value is:

[0093] (11)

[0094] In formula (11), is an integral gain coefficient.

[0095] The speed loop is adjusted by a first-order linear active disturbance rejection controller, and the pitch angle is adjusted by a second-order linear active disturbance rejection controller, so as to realize efficient and smooth control of the power output in the whole wind speed. Under wind speed fluctuation and external disturbance, the smoothness of the power output and the stable operation of the system are ensured by dynamically adjusting the speed and the pitch angle.

[0096] Embodiment 2: According to the control method adopted in the present application, the wind turbine power output simulation is carried out, and the wind turbine simulation parameters adopted are: , , , , , The rated wind speed is 10.5 m / s, and the rated power is 6 MW. In the low wind speed area shown in Figure 1 , the simulation is carried out, and the power output shown in Figure 2 can be obtained. As shown in Figure 2 , the output power of the present application is smoother than the traditional control (PSF) output in the low wind speed area, and the reduced power is the power fluctuation under random wind.

[0097] Embodiment 3: Based on embodiment 2, the simulation wind turbine parameters are the same as those in embodiment 2, and the simulation is carried out in the high wind speed area shown in Figure 3 , and the power output shown in Figure 4 can be obtained. As shown in Figure 4It can be known that in the high wind speed area, the control side rate adopted in the embodiment can maintain the rated power output and the power fluctuation is obviously reduced compared with the PSF control, and the application can ensure the smoothness of the power output and the stable operation of the system.

[0098] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A self-disturbing, full-wind-speed power smoothing method based on the kinetic energy of a wind turbine rotor, characterized in that, Includes the following steps: S1: Based on the wind turbine dynamics model, the rotor kinetic energy is calculated and its role in power fluctuation suppression is analyzed. Combined with the wind turbine operating characteristics, the energy regulation capability of rotor kinetic energy under different wind speed conditions is derived. In step S1, the mechanical power of the fan for: （1） In equation (1), air density, The radius of the wind turbine blades. For wind speed, The wind energy utilization coefficient, For the tip speed ratio, The pitch angle is the propeller angle. The influence coefficient of wind speed change rate, tip speed ratio The expression is: （2） In equation (2), This refers to the rotor angular velocity; Wind turbine rotor kinetic energy for: （3） In equation (3), It is the moment of inertia; The rate of change of rotor kinetic energy and the mechanical power of the fan and generator output power The relationship is: （4） In equation (4), The damping coefficient is the rate of change of power. S2: Design a first-order linear active disturbance rejection controller for speed loop control. Estimate the total system disturbance in real time by using an extended state observer and dynamically adjust the speed based on the first-order linear control law. In step S2, the first-order linear active disturbance rejection controller estimates the total system disturbance in real time through an extended state observer. This includes wind speed fluctuations, mechanical losses, and external disturbances. The disturbance estimation formula is: （5） In equation (5), This is the system state estimate. This is the disturbance estimate. To estimate the gain for the rotational speed state, Input gain for rotational speed. Estimate the gain for the total system disturbance. For system output, To control the input, They are respectively The derivative; Based on disturbance estimate Design control law for: （6） In equation (6), For reference input, This is the gain for the speed loop proportional control. To estimate the gain for the perturbation, For the speed loop integral control gain, This is the differential control gain for the speed loop; The first-order linear active disturbance rejection controller dynamically adjusts the rotor speed. The dynamic equation for the speed loop is: （7） In equation (7), For disturbance torque, for The derivative; S3: Design a second-order linear active disturbance rejection controller for pitch control. Through high-order disturbance estimation and compensation, optimize the dynamic adjustment performance of pitch and ensure the smoothness of power output of the wind turbine under sudden changes in wind speed or external disturbances. S4: Combining rotor kinetic energy and active disturbance rejection control technology, it dynamically generates active power reference values ​​and achieves smooth power output control by coordinating the speed loop and pitch control.

2. The self-disturbing full-wind-speed power smoothing method based on wind turbine rotor kinetic energy according to claim 1, characterized in that: In step S3, the second-order linear active disturbance rejection controller estimates the total system disturbance in real time through a higher-order extended state observer. and its rate of change The disturbance estimation formula is: （8） In equation (8), This is the system state estimate. This is the disturbance estimate. This is an estimate of the rate of change of the disturbance. Gain for pitch angle state estimation, Input gain for pitch angle. For system disturbance gain, The gain is the rate of change of the system disturbance. They are respectively The derivative; Based on disturbance estimate and estimated rate of change of disturbance Design control law for: （9） In equation (9), The gain is a proportional control for the pitch angle. To estimate the gain for the perturbation, To estimate the gain for the rate of change of the disturbance, The integral control gain for the pitch angle. The differential control gain for the pitch angle; The pitch angle is dynamically adjusted using a second-order linear active disturbance rejection controller. The dynamic equation for the pitch angle is: （10） In equation (10), This is a reference value for the pitch angle. It is a time constant. for The derivative of .

3. The self-disturbing full-wind-speed power smoothing method based on wind turbine rotor kinetic energy according to claim 1, characterized in that: In step S4, an active power reference value is generated by combining rotor kinetic energy and active disturbance rejection control technology. for: （11）； In equation (11), This is the integral gain coefficient.

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