Active-disturbance-rejection full-wind-speed power smoothing method based on kinetic energy of fan rotor

Abstract

The invention provides an active-disturbance-rejection full-wind-speed power smoothing method based on kinetic energy of a fan rotor, and belongs to the technical field of wind power control. The technical problem that the output power of a traditional wind turbine generator is unstable due to random fluctuation of the wind speed is solved. According to the technical scheme, the method comprises the following steps that S1, rotor kinetic energy is calculated based on a wind turbine kinetic model, and the effect of the rotor kinetic energy in power fluctuation stabilization is analyzed; s2, designing a first-order linear active disturbance rejection controller for rotating speed loop control; s3, designing a second-order linear active disturbance rejection controller for variable pitch control; and S4, dynamically generating an active power reference value by combining the kinetic energy of the rotor and an active disturbance rejection control technology, and controlling by coordinating a rotating speed ring and a variable pitch. The method has the beneficial effects that power fluctuation can be remarkably reduced under wind speed fluctuation and complex working conditions, the smoothness of power output is improved, meanwhile, the anti-interference capability and the dynamic stability of the system are enhanced, and efficient and stable operation of the wind driven generator system is ensured.

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] The technical problem solved by the present application is how to solve the above technical problems. SUMMARY

[0005] The present application aims to provide a self-disturbance full-wind-speed power smoothing method based on wind turbine rotor kinetic energy. The method introduces multiple self-disturbance control technologies on the basis of traditional direct power smoothing control methods based on kinetic energy storage, optimizes the speed ring control through a first-order linear self-disturbance controller, optimizes the variable pitch control through a second-order linear self-disturbance controller, and realizes efficient smoothing control of the wind turbine output power. 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 achieve the above-mentioned application purposes, 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: 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 the rotor kinetic energy under different wind speed conditions; S2: design a first-order linear self-disturbance controller for speed ring control, estimate the total disturbance of the system in real time through an 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; S3: design a second-order linear self-disturbance controller for variable pitch control, optimize the dynamic adjustment performance of the variable pitch through high-order disturbance estimation and compensation, and ensure the power output smoothness of the wind turbine under wind speed mutation or external disturbance; S4: combine the rotor kinetic energy and the self-disturbance control technology to dynamically generate the active power reference value, and realize efficient smoothing control of the power output through coordinated speed ring and variable pitch control.

[0007] Further, in the step S1, the mechanical power of the wind turbine is : (1) 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 change rate influence coefficient. The expression of the tip speed ratio is: (2) In formula (2), is the rotor angular velocity.

[0008] Wind turbine rotor kinetic energy is: (3) In formula (3), is the moment of inertia.

[0009] The rate of change of rotor kinetic energy and the mechanical power of the wind turbine and the generator output power is: (4) In formula (4), is the power rate of change damping coefficient.

[0010] 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 ability 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 ability 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 ability of the rotor kinetic energy is mainly used to cope with wind speed mutations to prevent power overruns.

[0011] 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: (5) In formula (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, are the derivatives of respectively; Based on the disturbance estimate , the control law is designed as: (6) 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 differential control gain, the integral term is used to eliminate steady-state error, and the differential term is used to improve dynamic response speed; The first-order linear active disturbance rejection controller dynamically adjusts the rotor speed , so that the speed loop can quickly recover stability under wind speed fluctuations and external interference. The dynamic equation of the speed loop is: (7) In formula (7), is the disturbance torque, for The derivative of .

[0012] Furthermore, in step S3, the second-order linear active disturbance rejection controller estimates the total disturbance of the system in real time through a high-order extended state observer. and its rate of change , the disturbance estimation formula is: (8) In formula (8), is the estimated value of the system state, is the disturbance estimate, is the estimated value of the disturbance change rate, is the pitch angle state estimation gain, is the pitch angle input gain, is the system disturbance gain, is the system disturbance change rate gain, They are The derivative of Based on the disturbance estimate and the estimated rate of change of disturbance , design control law for: (9) In formula (9), is the pitch angle proportional control gain, is the disturbance estimation gain, is the gain estimated for the disturbance change rate, is the pitch angle integral control gain, is the pitch angle differential control gain; Dynamically adjust the pitch angle by using a second-order linear active disturbance rejection controller , to ensure the smoothness of the wind turbine's power output under sudden changes in wind speed or external interference, the dynamic equation of the pitch angle is: (10) In formula (10), is the pitch angle reference value, is the time constant, for The integral term is used to further smooth the pitch angle variation.

[0013] Furthermore, in step S4, the active reference value is generated by combining the rotor kinetic energy and the active disturbance rejection control technology. for: (11) In formula (11), is the integral gain coefficient.

[0014] A first-order linear active disturbance rejection controller regulates the speed loop, while a second-order linear active disturbance rejection controller adjusts the pitch angle, achieving efficient and smooth control of power output at all wind speeds. Dynamic adjustment of the speed and pitch angle ensures smooth power output and stable system operation even under wind speed fluctuations and external disturbances.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention discloses a full-wind-speed power smoothing method based on active disturbance rejection (ADRC) of wind turbine rotor kinetic energy. By organically combining rotor kinetic energy with ADRC control technology, this method achieves efficient and smooth control of wind turbine output power. Furthermore, this invention significantly reduces power fluctuations under fluctuating wind speeds and complex operating conditions, improving power output smoothness while enhancing the system's anti-interference capabilities and dynamic stability, ensuring efficient and stable operation of the wind turbine system.

[0016] 2. This invention utilizes the wind turbine rotor's kinetic energy as a power buffer, establishing an energy regulation mechanism based on the rotor's dynamic characteristics. While traditional methods typically rely on external energy storage devices or sacrifice power generation efficiency to smooth power fluctuations, this invention utilizes the wind turbine rotor's kinetic energy to maintain smooth electromagnetic power output. This innovation reduces power fluctuations without increasing hardware costs, significantly improving power smoothing in areas below rated wind speeds. Tests have shown that under turbulent wind conditions, output power smoothness is 15% higher than with traditional PSF control.

[0017] 3、The application adopts a collaborative architecture of first-order and second-order linear active disturbance rejection control, solves the technical problem of strong coupling of the speed ring and the variable pitch ring in the traditional control. The simplified first-order LADRC designed for the speed ring estimates and compensates the disturbance in real time through the extended state observer, and improves the dynamic response of the system. The second-order LADRC designed for the variable pitch system effectively suppresses the mechanical resonance problem in the pitch angle adjustment process. Compared with the existing unified control strategy, this hierarchical control structure can maintain the rated power output when the system is in turbulent flow in the high wind speed area. At the same time, the application designs a linearization parameter setting method, which reduces the controller debugging parameters from 5 to 2 of the conventional ADRC, which not only maintains the disturbance rejection performance of the nonlinear control, but also greatly reduces the engineering implementation difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not limit the application.

[0019] Figure 1 The simulation schematic diagram of low wind speed area turbulent flow in the embodiment 2 of the application is shown.

[0020] Figure 2 The power output comparison chart when the low wind speed area turbulent flow in the embodiment 2 of the application is shown.

[0021] Figure 3 The simulation schematic diagram of high wind speed area turbulent flow in the embodiment 3 of the application is shown.

[0022] Figure 4 The power output comparison chart when the high wind speed area turbulent flow in the embodiment 3 of the application is shown.

[0023] Figure 5 The first-order linear active disturbance rejection speed ring vector control block diagram based on the rotor kinetic energy in the application is shown.

[0024] Figure 6 The second-order linear active disturbance rejection variable pitch control block diagram in the application is shown. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the application clearer, the application is further described in detail below in combination with the drawings and embodiments. Of course, the specific embodiments described here are only used to explain the application, and do not limit the application.

[0026] Embodiment 1: see Figure 1 、 Figure 2 、 Figure 5 、 Figure 6 The technical scheme of the embodiment is provided, which is a self-disturbance rejection full-wind-speed power smoothing method based on the rotor kinetic energy of the fan, including the following steps: S1: Based on the wind turbine dynamics model, calculate the rotor kinetic energy and analyze its role in power fluctuation smoothing. Combined with the wind turbine operating characteristics, derive the energy regulation capability of the rotor kinetic energy under different wind speed conditions; S2: Design a first-order linear active disturbance rejection controller for the speed loop. Use an extended state observer to estimate the total system disturbance in real time and dynamically adjust the speed based on a first-order linear control law to improve the speed loop's dynamic response speed and anti-interference capability. S3: Design a second-order linear active disturbance rejection controller for pitch control. By estimating and compensating for high-order disturbances, it optimizes the dynamic adjustment performance of pitch and ensures smooth power output of the wind turbine under sudden changes in wind speed or external disturbances. S4: Combines rotor kinetic energy with active disturbance rejection control technology to dynamically generate active power reference values. By coordinating the speed loop and pitch control, efficient and smooth control of power output is achieved.

[0027] In step S1, the mechanical power of the fan for: (1) 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, tip speed ratio The expression is: (2) In formula (2), is the rotor angular velocity.

[0028] Fan rotor kinetic energy for: (3) In formula (3), is the moment of inertia.

[0029] The rate of change of rotor kinetic energy and the mechanical power of the fan and generator output power The relationship is: (4) In formula (4), is the power change rate damping coefficient.

[0030] By adjusting the rotor speed, the rotor kinetic energy can be used as an energy buffer to smooth the full wind speed power output. Small, the rotor kinetic energy regulation ability is limited, mainly used to smooth small power fluctuations; in the condition of medium wind speed, the mechanical power Large, the rotor kinetic energy regulation ability is significantly enhanced, which can effectively suppress the power fluctuations caused by wind speed fluctuations; in the condition of high wind speed, the mechanical power Close to the rated value, the rotor kinetic energy regulation ability is mainly used to cope with wind speed mutations to prevent power over-limit.

[0031] 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: (5) In formula (5), is the system state estimation value, is the disturbance estimation value, is the speed state estimation gain, is the speed input gain, is the system total disturbance estimation gain, is the system output, is the control input, is the derivative of , respectively; Based on the disturbance estimation value , the control law is designed as: (6) 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 differential control gain, the integral term is used to eliminate the steady-state error, and the differential term is used to improve the dynamic response speed; 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 fluctuations and external disturbances, and the speed loop dynamic equation is: (7) In formula (7), is the disturbance torque, is the derivative of .

[0032] 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 the high-order extended state observer, and the disturbance estimation formula is: (8) In formula (8), is a system state estimation value, is a disturbance estimation value, is a disturbance rate of change 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 of change gain, is a derivative of respectively; Based on the disturbance estimation value and the disturbance rate of change estimation value , the control law is designed as: (9) In formula (9), is a pitch angle proportional control gain, is a disturbance estimation gain, is a disturbance rate of change estimation gain, is a pitch angle integral control gain, is a pitch angle derivative control gain; The pitch angle is dynamically adjusted by a second-order linear active disturbance rejection controller , to ensure the smoothness of power output of the wind turbine under sudden changes in wind speed or external disturbances. The pitch angle dynamic equation is: (10) 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.

[0033] In step S4, the rotor kinetic energy and the active disturbance rejection control technology are combined to generate the active reference value is: (11) In formula (11), is an integral gain coefficient.

[0034] 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, to achieve efficient and smooth control of power output over the entire wind speed. Under wind speed fluctuations and external disturbances, the smoothness of power output and the stable operation of the system are ensured by dynamically adjusting the speed and the pitch angle.

[0035] Example 2: The control method according to the application is used to simulate the power output of the fan, and the fan simulation parameters used are as follows: , , , , , The rated wind speed is 10.5 m / s, and the rated power is 6 MW. In the low wind speed area shown in Table 1, the turbulence is simulated, and the power output shown in Table 2 is obtained. As shown in Table 3, the output power of the application is smoother than that of the traditional control (PSF) in the low wind speed area, and the reduced power reduces the power fluctuation under random wind. Figure 1 Figure 2 Figure 2

[0036] Example 3: Based on Example 2, the fan parameters are the same as those in Example 2, and in the high wind speed area shown in Table 4, the turbulence is simulated, and the power output shown in Table 5 is obtained. As shown in Table 6, in the high wind speed area, the control method used in this embodiment can maintain the rated power output and significantly reduce the power fluctuation compared with the PSF control. The application can ensure the smoothness of the power output and the stable operation of the system. Figure 3 Figure 4 Figure 4

[0037] The above description is only a preferred embodiment of the application and is not intended to limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.​​​​​​

Claims

1. A full-wind-speed power smoothing method based on wind turbine rotor kinetic energy using active disturbance rejection, characterized in that: The following steps are involved: S1: Based on the wind turbine dynamics model, calculate the rotor kinetic energy and analyze its role in power fluctuation smoothing. Combined with the wind turbine operating characteristics, derive the energy regulation capability of the rotor kinetic energy under different wind speed conditions; S2: Design a first-order linear active disturbance rejection controller for speed control. Use an extended state observer to estimate the total system disturbance in real time and dynamically adjust the speed based on a first-order linear control law. S3: Design a second-order linear active disturbance rejection controller for pitch control. By estimating and compensating for high-order disturbances, it optimizes the dynamic adjustment performance of pitch and ensures smooth power output of the wind turbine under sudden changes in wind speed or external disturbances. S4: Combines rotor kinetic energy with active disturbance rejection control technology to dynamically generate active power reference values, and achieves smooth control of power output by coordinating the speed loop and pitch control.

2. The wind turbine rotor kinetic energy-based auto-disturbance rejection full wind speed power smoothing method according to claim 1 is characterized by: In step S1, the mechanical power of the fan for: （1） 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, tip speed ratio The expression is: （2） In formula (2), is the rotor angular velocity; Fan rotor kinetic energy for: （3） In formula (3), 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 formula (4), is the power change rate damping coefficient.

3. The wind turbine rotor kinetic energy-based auto-disturbance rejection full wind speed power smoothing method according to claim 1, characterized in that: 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, the disturbance estimation formula is: （5） In formula (5), is the estimated value of the system state, is the disturbance estimate, is the speed state estimation gain, is the speed input gain, is the total disturbance estimated gain of the system, is the system output, is the control input, They are The derivative of Based on the disturbance estimate , design control law for: （6） 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 differential control gain; The first-order linear active disturbance rejection controller dynamically adjusts the rotor speed , the dynamic equation of the speed loop is: （7） In formula (7), is the disturbance torque, for The derivative of .

4. The wind turbine rotor kinetic energy-based auto-disturbance rejection full wind speed power smoothing method according to claim 1, characterized in that: In step S3, the second-order linear active disturbance rejection controller estimates the total disturbance of the system in real time through a high-order extended state observer. and its rate of change , the disturbance estimation formula is: （8） In formula (8), is the estimated value of the system state, is the disturbance estimate, is the estimated value of the disturbance change rate, is the pitch angle state estimation gain, is the pitch angle input gain, is the system disturbance gain, is the system disturbance change rate gain, They are The derivative of Based on the disturbance estimate and the estimated rate of change of disturbance , design control law for: （9） In formula (9), is the pitch angle proportional control gain, is the disturbance estimation gain, is the disturbance change rate estimation gain, is the pitch angle integral control gain, is the pitch angle differential control gain; Dynamically adjust the pitch angle by using a second-order linear active disturbance rejection controller , the dynamic equation of the pitch angle is: （10） In formula (10), is the pitch angle reference value, is the time constant, for The derivative of .

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

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