A nonlinear active disturbance rejection control method for a power generation steam turbine and related equipment

Abstract

The present application discloses a nonlinear auto-disturbance rejection control method for a steam turbine generator and related equipment. The method comprises: obtaining a mathematical model of the steam turbine electro-hydraulic control system and determining a transfer function; constructing a control equation for a feedback structure based on the transfer function; constructing a target extended state function of a nonlinear extended observer using a logarithmic function and a hyperbolic tangent function; and applying the control equation and the target extended state function to a marine steam turbine generator to implement nonlinear auto-disturbance rejection control for the marine steam turbine generator. The present application constructs a novel nonlinear extended state observer using logarithmic and hyperbolic tangent functions, introducing nonlinear factors to better improve the dynamic characteristics of the nonlinear auto-disturbance rejection controller, thereby enhancing the robustness and control quality of the steam turbine generator under fault conditions such as large load step changes and abnormal oil pressure, which is of great significance for improving the safety and stability of unit operation.

Description

Technical Field

[0001] The present application relates to the technical field of active disturbance rejection control, and in particular to a nonlinear active disturbance rejection control method for a power generation steam turbine and related equipment. Background Art

[0002] Steam turbines are the heart of ships, and their stable and reliable operation is essential for safe navigation. The proportional-integral-derivative (PID) algorithm is a widely used control strategy for steam turbines. This method, which eliminates errors based on error and does not rely on a precise mathematical model of the controlled object, has become widely popular in engineering practice. PID controllers achieve satisfactory control results when the power grid operates smoothly and the load does not fluctuate significantly.

[0003] However, unlike land-based steam turbines, marine steam turbines typically operate in isolated grids, and the simple assumption of a largely constant load cannot be made. Furthermore, new ships using all-electric propulsion often face drastic load changes, sudden load rejection, and frequent operating condition changes. These conditions result in significant perturbations in the system's transfer function parameters. Traditional PID algorithms, due to their inability to adapt their parameters, no longer meet industrial control requirements. Traditional control algorithms for the regulation of steam turbines on new all-electric propulsion ships suffer from long settling times, poor interference rejection, and low robustness. Summary of the Invention

[0004] In order to solve the above technical problems, embodiments of the present application provide a nonlinear active disturbance rejection control method and device for a power generation steam turbine, a nonlinear active disturbance rejection controller, an electronic device, a computer-readable storage medium, and a computer program product.

[0005] In a first aspect, in order to solve the above technical problems, the present application provides a nonlinear active disturbance rejection control method for a power generation steam turbine, comprising:

[0006] Obtain the mathematical model of the steam turbine electro-hydraulic control system and determine the transfer function;

[0007] constructing a control equation of a feedback structure based on the transfer function;

[0008] The target extended state function of the nonlinear extended observer is constructed using logarithmic function and hyperbolic tangent function;

[0009] The control equation and the target extended state function are applied to a marine power generation steam turbine to implement nonlinear active disturbance rejection control for the marine power generation steam turbine.

[0010] The beneficial effects are:

[0011] In the technical solution provided in the embodiment of the present application, a new type of nonlinear extended state observer is constructed by logarithmic function and hyperbolic tangent function, and the control equation of the feedback structure is determined based on the mathematical model of the steam turbine electro-hydraulic control system. The feedback structure applying the above control equation and the nonlinear extended observer applying the above target extended state function are combined into a nonlinear auto-disturbance rejection controller, which is applied to marine power generation steam turbines to realize nonlinear auto-disturbance rejection control for marine power generation steam turbines. The present application introduces nonlinear factors to better improve the dynamic characteristics of the nonlinear auto-disturbance rejection controller, thereby improving the control effect and control quality. Compared with linear auto-disturbance rejection control, when the external load changes significantly, the nonlinear auto-disturbance rejection control scheme of the present application can more effectively suppress the speed surge, improve the system's anti-disturbance capability, and achieve stable control of the marine power generation steam turbine.

[0012] In a second aspect, the present invention provides a nonlinear active disturbance rejection controller, which applies the nonlinear active disturbance rejection control method for a power generation steam turbine as described above, and includes a feedback structure and a nonlinear extended state observer, wherein the feedback structure is a proportional differential feedback structure;

[0013] The feedback structure applies a control equation determined by a transfer function of a mathematical model of a steam turbine electro-hydraulic control system, and the nonlinear extended state observer applies a target extended state function constructed by a logarithmic function and a hyperbolic tangent function;

[0014] The feedback structure is connected to the control object, the nonlinear extended state observer is connected to the feedback structure and the control object, and the feedback structure performs feedback control on the input value based on the observation value output by the nonlinear extended state observer and transmits it to the control object.

[0015] In a third aspect, the present invention provides a nonlinear active disturbance rejection control device for a power generation steam turbine, comprising an acquisition unit, a feedback unit, a function construction unit, and an application unit;

[0016] An acquisition unit, used for acquiring a mathematical model of the steam turbine electro-hydraulic control system and determining a transfer function;

[0017] A feedback unit, configured to obtain a control equation of a feedback structure based on the transfer function;

[0018] A function construction unit, used for constructing a target extended state function of a nonlinear extended observer using a logarithmic function and a hyperbolic tangent function;

[0019] An application unit is used to apply the control equation and the target expanded state function to a marine power generation steam turbine to implement nonlinear active disturbance rejection control for the marine power generation steam turbine.

[0020] In a fourth aspect, the present application also provides an electronic device comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the electronic device implements the nonlinear self-anti-disturbance control method of the power generation turbine as described above.

[0021] In a fifth aspect, the present application also provides a computer-readable storage medium having computer-readable instructions stored thereon. When the computer-readable instructions are executed by a processor of a computer, the computer executes the nonlinear self-disturbance rejection control method for a power generation steam turbine as described above.

[0022] In a sixth aspect, the present application further provides a computer program product or computer program, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the nonlinear active disturbance rejection control method for a power generation steam turbine provided in the various optional embodiments described above.

[0023] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, serving to explain the principles of the present application. It is obvious that the drawings described below are merely some embodiments of the present application, and a person of ordinary skill in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0025] Figure 1 is a flow chart of a nonlinear active disturbance rejection control method for a power generation steam turbine shown in an exemplary embodiment of the present application;

[0026] Figure 2 is a schematic diagram of a mathematical model of a steam turbine electro-hydraulic control system in an exemplary embodiment of the present application;

[0027] Figure 3 1 is a schematic diagram of a nonlinear active disturbance rejection controller applying a nonlinear active disturbance rejection control method for a power generation steam turbine, shown in an exemplary embodiment of the present application;

[0028] Figure 4 is a schematic diagram of a nonlinear extended state observer in an exemplary embodiment of the present application;

[0029] Figure 5is a steady-state comparison diagram of the ESO set using the fal function and the nonlinear ESO set using the falLT function in an exemplary embodiment of the present application;

[0030] Figure 6 It is a schematic diagram of the speed control curves of different controllers during the simulation experiment;

[0031] Figure 7 This is a schematic diagram of the oil pressure abnormal robustness curves of different controllers during the simulation experiment;

[0032] Figure 8 is a block diagram of an active disturbance rejection control device shown in an exemplary embodiment of the present application;

[0033] Figure 9 It is a structural diagram of a computer system suitable for implementing the electronic device of the embodiment of the present application. DETAILED DESCRIPTION

[0034] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different figures represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0035] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0036] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0037] In this application, "plurality" refers to two or more. "And / or" describes the relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0038] In order to solve the problems of long adjustment time, poor anti-interference ability and low robustness of traditional control algorithms in the regulation and control of new all-electric propulsion ship generator turbines, the embodiments of the present application propose a nonlinear active disturbance rejection control method and device for a generator turbine, a nonlinear active disturbance rejection controller, an electronic device, and a computer-readable storage medium, which mainly involve the nonlinear active disturbance rejection control method technology of a generator turbine included in the turbine active disturbance rejection technology. These embodiments will be described in detail below.

[0039] First see Figure 1 , Figure 1 FIG. 1 is a flow chart of a nonlinear active disturbance rejection control method for a steam turbine generator system according to an exemplary embodiment of the present invention. Figure 1 As shown, in an exemplary embodiment, the nonlinear active disturbance rejection control method for a power generation steam turbine may include steps S101 to S104, which are described in detail as follows:

[0040] Step S101: Obtain a mathematical model of the steam turbine electro-hydraulic control system and determine a transfer function.

[0041] Step S102: constructing a control equation of the feedback structure based on the transfer function.

[0042] The mathematical model of a steam turbine electro-hydraulic control system typically treats the turbine control system as a general object model. Based on their characteristics, the system components are broken down into transfer functions connected in series, creating a mathematical model. The control system of a marine steam turbine consists of several key components, including a controller, servo amplifier, electro-hydraulic converter, and hydraulic motor. The signal conversion process in this system is as follows: the electrical signal from the controller is first converted into a hydraulic signal, which then drives the control valve, changing the valve opening, adjusting the steam inlet and changing the steam space pressure, thereby controlling the speed. The rotor speed is finally converted into an electrical signal by a sensor and sent back to the controller, completing the closed-loop control.

[0043] In the embodiment provided in the present application, the transfer functions of the components in the mathematical model are obtained, and the control equations of the feedback structure in the nonlinear active disturbance rejection controller for controlling the steam turbine electro-hydraulic control system are determined based on the transfer functions.

[0044] like Figure 2 As shown, Figure 2 This is a schematic diagram of the mathematical model of the steam turbine electro-hydraulic control system in an exemplary embodiment of the present application. Generally, to facilitate the analysis and design of the control system, it can be considered as a first-order system. If the input current of the speed controller is i and the valve position of the servo valve core is x v , the oil motor valve position is χ z , the transfer function between the electro-hydraulic servo valve and the oil motor can be expressed by equations (1) and (2):

[0045]

[0046] Where T e 、T o Indicates the time constant of the electro-hydraulic servo valve and the oil motor.

[0047] Marine steam turbines typically operate with saturated wet steam, which has a low operating pressure and minimal enthalpy drop. Therefore, they typically have a single-cylinder structure and lack a reheater. Changes in the opening of the regulating valve cause changes in pressure, which in turn alters the saturation of the water film. Some steam can escape from or be absorbed by the film, significantly different from local thermal power steam turbines.

[0048] If the water film mass is G, the temperature is T, the enthalpy is i, the latent heat of vaporization is γ, and the tube wall temperature is T w , the heat transfer coefficient is α, the heat transfer area is A, the steam density is ρ, and the steam flow rate is q m , according to the law of conservation of energy, heat transfer formula and mass conservation:

[0049]

[0050] Q=α(T w -T)A (4)

[0051]

[0052] Considering water as saturated water, and considering both temperature and enthalpy as functions of pressure, combining equations (3)-(5) yields:

[0053]

[0054] The difference is not big, the heat transfer can be ignored, and it can be obtained from formula (6):

[0055]

[0056] Consider flow rate as a function of valve opening s z and steam pressure p, since the valve opening at the steam volume outlet does not change, the outlet flow rate q m2 Considered to be only related to pressure, q m1 =q m1 (s z ,p),q m2 =q m2 (p).

[0057] In the working range of the steam turbine, the specific heat c p Considered as a constant, di=c p dT. The pressure and valve opening at the working point of equation (7) are p0, s z0, expand the Taylor formula, and finally get formula (8) and formula (9) after Laplace transformation and per-unit normalization:

[0058]

[0059] (T a +T b ) p (s)s=χ sz (s)-Kχ p (s) (9)

[0060] where q m10 is the rated operating flow, χ p =Δp / p0,χ sz =Δs z / s z0 ,

[0061] When in a stable state, χ p (s)s=0,χ sz (s) = 1, χ p (s) = 1, from which the transfer function of the steam space is:

[0062]

[0063] Where T a is the steam volume time constant of thermal power turbine, T b The time constant of a marine steam turbine is larger than that of a thermal power unit because of the increase in the time constant caused by the water film.

[0064] The nuclear steam turbine rotor equation is not much different. Based on Newton's second law and Taylor expansion expression near the operating point, after per-unit processing, it can be expressed as:

[0065]

[0066] Where T a is the rotor lift-off time constant, β is the rotor self-balancing coefficient, χ ω is the relative change in speed, χ p is the relative change in pressure, χ pL is the relative change of load. According to the above transfer functions, the mathematical model of the steam turbine electro-hydraulic control system is finally obtained.

[0067] Step S103 : constructing a target extended state function of the nonlinear extended observer using a logarithmic function and a hyperbolic tangent function.

[0068] The Extended State Observer (ESO) is a key component of ADRC. It estimates the system's state variables through its inputs and outputs and is responsible for transforming the standard control system form (Equation (12)) into an integral series system (Equation (13), where x represents the system state, f represents the nonlinear factor, u represents the input, and w represents the disturbance. The nonlinear factor, model uncertainty, and external disturbance are treated as a total disturbance and act as high-order derivatives of the system, enabling active feedforward compensation through the ESO.

[0069]

[0070]

[0071] Although the use of linear functions in the expanded observer facilitates system analysis and parameter tuning, its anti-interference ability is limited due to the limitations of the linear structure. In addition, the reasonable introduction of some nonlinear factors can better improve the dynamic characteristics of the system and enhance the control effect.

[0072] Therefore, taking the above problems into consideration, in the embodiments provided in the present application, nonlinear factors are introduced to help improve the control quality. Specifically, a target extended state function is constructed based on a combination of a logarithmic function and a hyperbolic tangent function, and applied to a nonlinear extended observer to construct a nonlinear active disturbance rejection controller to realize a nonlinear active disturbance rejection control method for a power generation turbine.

[0073] Step S104 : applying the control equation and the target extended state function to the marine steam turbine to implement nonlinear active disturbance rejection control for the marine steam turbine.

[0074] An active disturbance rejection controller (ADRC) typically consists of a tracking differentiator, an extended state observer, and a linear or nonlinear feedback structure. The tracking differentiator softens the input signal, resolving the trade-off between speed and accuracy. In linear ADRC design, the tracking differentiator is often omitted to facilitate dynamic analysis of the system, simplifying the design to a combination of a linear extended observer and a proportional-derivative (PD) linear error feedback control rate.

[0075] In the embodiments provided in the present application, a nonlinear active disturbance rejection controller is constructed using a feedback structure that applies the above-mentioned control equation and a nonlinear extended observer that applies the above-mentioned target extended state function, and is applied to a marine power generation steam turbine to implement nonlinear active disturbance rejection control for the marine power generation steam turbine.

[0076] As can be seen from the above, in the method provided in this embodiment, a new type of nonlinear extended state observer is constructed by logarithmic function and hyperbolic tangent function, and the control equation of the feedback structure is determined based on the mathematical model of the steam turbine electro-hydraulic control system. The feedback structure applying the above control equation and the nonlinear extended observer applying the above target extended state function are combined into a nonlinear auto-disturbance rejection controller, which is applied to the marine generator steam turbine to realize nonlinear auto-disturbance rejection control for the marine generator steam turbine. The present application introduces nonlinear factors to better improve the dynamic characteristics of the nonlinear auto-disturbance rejection controller, thereby improving the control effect and control quality. Compared with linear auto-disturbance rejection control, when the external load changes significantly, the nonlinear auto-disturbance rejection control scheme of the present application can more effectively suppress the speed surge, improve the system's primary frequency modulation capability, and achieve stable control of the marine generator steam turbine.

[0077] In the active disturbance rejection controller, the fal function is generally used in the extended observer, and its function expression is:

[0078]

[0079] This function consists of a power function and a linear function. Currently, parameter tuning for this type of nonlinear ADRC controller is primarily based on experience. The main parameters in the fal(x) function are α and δ. Parameter α primarily determines the rate of growth of the fal(x) output away from the origin; a larger α indicates a faster output growth. δ controls the size of the linear interval and the slope of the linear function. However, when a linear interval is introduced at the origin, the error converges from a power function to a linear function when the error is sufficiently small. Furthermore, the function does not smoothly transition at the segmentation points, resulting in overshoot.

[0080] In an exemplary embodiment provided by the present application, the expression of the target extended state function fallT of the nonlinear extended observer constructed using the logarithmic function and the hyperbolic tangent function is:

[0081]

[0082] When the input is too large, the tanh(bx) value approaches 1, mainly due to log a (x+1) or log 1 / a (1-x) determines the output. When the input decreases, the idea of ​​small error and large gain is mainly achieved by tanh(bx).

[0083] In addition, even when too many nonlinear factors are involved, the target expansion state function in the method provided by the present application is stable, and the stability of the logarithmic part and the hyperbolic tangent part can be proved separately.

[0084] First, we prove the stability of the logarithmic part. Taking the second-order control system as an example, when the error is greater than zero, the error matrix of the system can be expressed as:

[0085]

[0086] Construct a Lyapunov function:

[0087]

[0088] When β2 is greater than zero, the function is positive definite, and its partial derivative with respect to e1 and e2 is:

[0089]

[0090] The derivative of the above Lyapunov function is:

[0091]

[0092] When β1>0, The observer converges, and the same applies when the error e1 is less than 0.

[0093] Next, we prove the stability of the hyperbolic tangent part. By Lyapunov's lemma, for the error matrix:

[0094]

[0095] If there exists a symmetric matrix D:

[0096]

[0097] The main diagonal elements of the matrix D are all positive, so that the matrix DA(e) is positive definite, then the system is stable in the sense of Lyapunov. Let F = tanh(be1) / e1, then F∈(0,1), and it is a bounded function. If DA(e) is positive definite, it is equivalent to:

[0098] β1d 11 +β2Fd 12 >0

[0099] d 11 =β1d 12 -β2Fd 22

[0100]

[0101] When β1,β2>0, we only need to set d 11 =1,d 12 =1,d 22 =β1 / Fβ2 can satisfy the stability under Lyapunov conditions.

[0102] It can be seen that the target expanded state function constructed by the above embodiment of the present application inherits the characteristics of the traditional fal function in small error and large gain, large error and small gain, and at the same time solves the overshoot phenomenon caused by its discontinuity at the segmentation point.

[0103] In an exemplary embodiment provided by the present application, the nonlinear extended observer is a third-order extended state observer, and the corresponding specific steps of applying the control equation and the target extended state function to the marine power generation steam turbine may include:

[0104] Based on the target expanded state function, a first target state observation value, a second target state observation value, and a third target state observation value of a third-order nonlinear expanded observer are obtained;

[0105] applying a control equation to a feedback structure, applying a first target state observation, a second target state observation, and a third target state observation to a nonlinear extended observer;

[0106] An active disturbance rejection controller consisting of a feedback structure and a nonlinear extended observer is applied to a marine steam turbine.

[0107] In this embodiment, the first target state observation value is z1, the derivative of z1 is z2+β1e, the second target state observation value is z2, the derivative of z2 is z3+β2falLT1(e), the third target state observation value is z3, the derivative of z3 is β3falLT2(e), e is the error value of the input nonlinear expansion observer, β1, β2 and β3 are the observer gain parameters, where β1=3ω o , β2=3ω o 2 ,β3=4β2,ω c is the feedback structure bandwidth, ω c =10 / t s ,ω o is a nonlinear extended observer, ω o =4ω c , t s is the system adjustment time, t s 3s.

[0108] For control systems of second order or higher, the system input gain is an important parameter that affects system stability. Therefore, the system input gain is used as an adjustable variable to improve the control effect of the system. Therefore, in another exemplary embodiment provided by this application, the specific steps of applying the active disturbance rejection controller composed of a feedback structure and a nonlinear extended observer to a marine steam turbine in the above-mentioned embodiment may include:

[0109] Get pre-configured system gain parameters;

[0110] An active disturbance rejection controller is constructed based on a feedback structure and a nonlinear extended observer using first target state observation value, second target state observation value and third target state observation value, and is applied to a marine power generation steam turbine.

[0111] In this way, the present application applies the target expanded state function to the nonlinear active disturbance rejection controller through the above embodiment to implement nonlinear active disturbance rejection control for marine power generation steam turbines, improve the control effect, and help improve the control quality.

[0112] In an exemplary embodiment provided by this application, the specific steps of obtaining the control equation of the feedback structure based on the transfer function may include:

[0113] Get the preset extreme value;

[0114] Obtaining a correspondence between pole values ​​and structural gain parameters of the feedback structure based on the transfer function;

[0115] The structural gain parameters of the feedback structure are obtained based on the corresponding relationship and the pole value;

[0116] The control equation of the feedback structure is obtained based on the structural gain parameter:

[0117] u0=k p (z1-R)-k d z2

[0118] Among them, R is the input value of the input feedback structure, z1 and z2 are the observation values ​​output by the nonlinear expansion observer, and k p 、k d is the structural gain parameter.

[0119] The nonlinear extended observer of the nonlinear active disturbance rejection control provided in this embodiment can completely transform the control system into a series integral standard form. Theoretically, for a pure integral series system, the farther the distance between the selected pole and the origin, the better the control effect. However, considering the actual situation, if the selected pole is too large, it will cause system instability. Preferably, the preset pole value σ=12.

[0120] The transfer function of the mathematical model of the steam turbine electro-hydraulic control system reflects the transmission relationship between data signals. The nonlinear active disturbance rejection controller in the feedback structure is used to control the steam turbine electro-hydraulic control system, thereby completing the conversion of various electrical signals in the steam turbine electro-hydraulic control system. Therefore, after determining the extreme value based on the transfer function, the structural gain parameter k can be obtained. p With k d The relationship with the selected pole is k p =σ 2 , k d =2σ, and the control equation of the feedback structure is obtained:

[0121] u0=k p (z1-R)-k d z2

[0122] Among them, R is the input value of the input feedback structure, z1 and z2 are the observation values ​​output by the nonlinear expansion observer, and k p 、k d is the structural gain parameter.

[0123] See also Figure 3 , Figure 3 FIG. 1 is a schematic diagram of a nonlinear active disturbance rejection controller using a nonlinear active disturbance rejection control method for a power generation steam turbine, as shown in an exemplary embodiment of the present application. Figure 3 As shown, the active disturbance rejection controller includes a feedback structure 310 and a nonlinear extended state observer 320, and the feedback structure 310 is a PD controller;

[0124] The feedback structure 310 applies a control equation determined by a transfer function of a mathematical model of the steam turbine electro-hydraulic control system, and the nonlinear extended state observer 320 applies a target extended state function constructed by a logarithmic function and a hyperbolic tangent function;

[0125] The feedback structure 310 is connected to the control object, and the nonlinear extended state observer 320 is connected to the feedback structure 310 and the control object. The feedback structure 310 performs feedback control on the input value based on the observation value output by the nonlinear extended state observer 320 and transmits it to the control object.

[0126] When used, for the third-order nonlinear ESO (Extended State Observer) in this embodiment, there are three state variables that need to be estimated: the system output y, the derivative of the system output And the total disturbance of the system. The observation of y by nonlinear ESO is recorded as z1, The observation of the system state is denoted as z2, and the observation of the disturbance is denoted as z3. When the nonlinear ESO estimates the system state and the disturbance, this information is used for feedback control via the floating loss structure. The nonlinear active disturbance rejection controller calculates the control input based on these estimates to achieve precise control of the system output.

[0127] Among them, the linear feedback control law of the PD controller can ensure asymptotic stability, and the controller is easy to design, so it is widely used in industrial robot control.

[0128] like Figure 4 As shown, Figure 4 FIG. 1 is a schematic diagram of a nonlinear extended state observer in an exemplary embodiment of the present application. Figure 4As shown, the nonlinear extended state observer 320 is a third-order extended state observer, including a first nonlinear function module 321, a second nonlinear function module 322 and a third nonlinear function module 323; the target state observation values ​​corresponding to the first nonlinear function module 321, the second nonlinear function module 322 and the third nonlinear function module 323 are z1, z2 and z3 respectively, the derivative of the first target state observation value z1 is z2+β1e, the derivative of the second target state observation value z2 is z3+β2falLT1(e), and the derivative of the third target state observation value z3 is β3falLT2(e), e is the error value input to the nonlinear extended observer, and β1, β2 and β3 are observer gain parameters.

[0129] One end of the first nonlinear function module 321, the second nonlinear function module 322 and the third nonlinear function module 323 is connected to the input end of the nonlinear extended state observer 320, and the other end is connected to the corresponding integration module 324 to output corresponding observation values.

[0130] The steady-state error of the system caused by the traditional ESO using the fall function and the nonlinear ESO using the fallT function provided by the embodiment of the present application is as follows:

[0131]

[0132] The error system of ESO built by fal function and nonlinear ESO built by falLT is:

[0133]

[0134] For the convenience of analysis, the linear segment is discarded and the fal function is simplified to fal(x)=|x| 1 / 2 sign(x), then when the system enters a steady state, Thus, e1=(w / β2) 2 , e2=β1(w / β2) 2 , it can be seen that the system's steady-state error, e1, decreases exponentially with increasing parameter β2, resulting in a much higher efficiency than the linear observer error, e1 = w / β2. However, for power functions with exponential terms less than 1, the slope is very large in a small neighborhood near the origin, and the derivative is almost non-existent. Therefore, introducing a high-slope linear function near the origin to alleviate this problem leads to a decrease in ESO performance.

[0135] When the system enters a steady state, assuming the error is greater than 0, then w=β2(log a (e1+1)+tanh(be1)), when the error is w / β2>tanh(be1), because the function is increasing, the sign of the inequality remains unchanged after taking the inverse function, and we have:

[0136]

[0137] Take b = 5, then Figure 5 It can be seen that when b is larger, the falLT function will converge faster and be smooth and differentiable everywhere, without the need to introduce a linear function near the zero point. Figure 5 It is a steady-state comparison diagram of the ESO set using the fall function and the nonlinear ESO set using the fallT function in the exemplary embodiment of the present application.

[0138] In another embodiment provided in the present application, after the construction of the nonlinear active disturbance rejection controller is completed, the control effect of the nonlinear active disturbance rejection controller (LTADRC) can be verified through a load disturbance simulation experiment.

[0139] A steam turbine control system was built on the Simulink platform (a simulation platform) to evaluate the disturbance rejection and robustness of a traditional linear active disturbance rejection controller, the nonlinear active disturbance rejection controller (LTADRC) designed in this application, and a PID controller under severe load rejection and abnormal oil pressure in the hydraulic motor. The rated speed of the steam turbine was normalized to 1. The disturbance was simulated by introducing a negative step signal at the 10th second of stable operation to simulate turbine load rejection. The oil pressure abnormality was simulated by increasing the time constant of the hydraulic motor.

[0140] Tables 1 and 2 summarize the overshoot and settling time of the three control strategies for turbines under different load shedding conditions. Settling time is defined as the time required to return to a speed within a 0.5% error band after a disturbance is introduced, and overshoot is defined as the deviation between the peak speed and the rated speed. It can be seen that the PID controller, linear active disturbance rejection controller, and the proposed active disturbance rejection controller can all suppress the speed within a 3% error during sudden load shedding, with settling times of less than 3 seconds, meeting design requirements. Furthermore, the LTADRC minimizes overshoot and settling time. The specific process is as follows: Figure 6 , Figure 6 It is a schematic diagram of the speed control curves of different controllers during the simulation experiment.

[0141] Table 1: Comparison of overshoot of different controllers

[0142]

[0143] Table 2: Comparison of adjustment time of different controllers

[0144]

[0145] from Figure 6It can be seen that when a linear active disturbance rejection control strategy is used to address a severe load rejection, the speed does not smoothly return to rated speed. This is primarily due to the structural limitations of the extended state observer (ESO) when using a low-order linear active disturbance rejection control strategy for a high-order system, preventing it from accurately tracking disturbances, leading to chatter. This situation can usually be addressed by increasing the order of the ESO to utilize more known system information. However, introducing appropriate nonlinear factors can improve the disturbance rejection performance compared to a linear active disturbance rejection control strategy at the same order.

[0146] Robustness is another important metric for controller validation. It describes the system's ability to maintain stable control despite changes in dynamic characteristics. In the regulation and control systems of marine steam turbines, abnormal oil pressure in the hydraulic motor is a typical fault, manifesting primarily as a change in the time constant of the hydraulic motor. Reducing the hydraulic motor time constant and shifting the cutoff frequency to the right improves control signal response and increases stability margin. To this end, the time constant of the hydraulic motor transfer function was doubled to simulate abnormal oil pressure. A negative 0.15 transition signal was introduced after the system had been operating stably for 10 seconds to observe the control effect.

[0147] from Figure 7 It can be seen that when the time constant of the oil motor increases, both the linear active disturbance rejection control and the nonlinear active disturbance rejection control experience vibration, the overshoot of LADRC is 0.8%, and the overshoot of LTADRC is 4.1%. Figure 7 Figure 2 shows the robustness curves for oil pressure anomalies of different controllers during simulation experiments. The LADRC takes approximately 2.5 seconds to recover to the 0.5% error band, while the LTADRC takes 3.5 seconds. Although linear control appears superior to nonlinear control in terms of overshoot and recovery time, the nonlinear control exhibits significantly lower oscillation frequency than the linear control, demonstrating its superior robustness.

[0148] As can be seen from the embodiments provided herein, the nonlinear ADRC controller, compared to a linear ADRC controller, is more effective at suppressing speed spikes when subjected to significant external load changes, thereby improving the system's primary frequency regulation capability. Furthermore, simulations using a hydraulic motor time constant to simulate an oil pressure fault demonstrate that the nonlinear ADRC controller exhibits greater robustness than the linear ADRC controller itself.

[0149] Figure 8 FIG. 8 is a block diagram of an active disturbance rejection control device 800 shown in an exemplary embodiment of the present application. Figure 8 As shown, the device includes:

[0150] An acquisition unit 801 is used to acquire a mathematical model of the steam turbine electro-hydraulic control system and determine a transfer function;

[0151] A feedback unit 802 is configured to obtain a control equation of the feedback structure based on the transfer function;

[0152] A function construction unit 803 is used to construct a target extended state function of a nonlinear extended observer using a logarithmic function and a hyperbolic tangent function;

[0153] The application unit 804 is configured to apply the control equation and the target extended state function to the marine power generation steam turbine, so as to implement nonlinear active disturbance rejection control for the marine power generation steam turbine.

[0154] The device applies the nonlinear active disturbance rejection control method for a power generation steam turbine provided by the present application. A new nonlinear extended state observer is constructed by using a function construction unit 803 using a logarithmic function and a hyperbolic tangent function. The control equation of the feedback structure is determined based on the mathematical model of the steam turbine electro-hydraulic control system using a feedback unit 802. The application unit 804 applies the feedback structure of the control equation and the nonlinear extended observer using the target extended state function to form a nonlinear active disturbance rejection controller, which is applied to a marine power generation steam turbine to achieve nonlinear active disturbance rejection control for the marine power generation steam turbine. The present application introduces nonlinear factors to better improve the dynamic characteristics of the nonlinear active disturbance rejection controller, thereby improving the control effect and control quality. Compared with linear active disturbance rejection control, when the external load changes significantly, the nonlinear active disturbance rejection control scheme of the present application can more effectively suppress the speed surge, improve the system's primary frequency modulation capability, and achieve stable control of the marine power generation steam turbine.

[0155] In another exemplary embodiment, the nonlinear extended observer is a third-order extended state observer; the application unit 804 is further used to obtain a first target state observation value, a second target state observation value, and a third target state observation value of the third-order nonlinear extended observer based on the target extended state function; the control equation is applied to the feedback structure, and the first target state observation value, the second target state observation value, and the third target state observation value are applied to the nonlinear extended observer; the active disturbance rejection controller consisting of the feedback structure and the nonlinear extended observer is applied to a marine power generation turbine; wherein, the first target state observation value is z1, and the derivative of z1 is z2+β1e, the second target state observation value is z2, and the derivative of z2 is z3+β2falLT1(e), the third target state observation value is z3, and the derivative of z3 is β3falLT2(e), e is the error value input to the nonlinear extended observer, and β1, β2, and β3 are observer gain parameters.

[0156] In another exemplary embodiment, the application unit 804 is further configured to obtain pre-configured system gain parameters; form an active disturbance rejection controller based on the system gain parameters, the feedback structure, and the nonlinear extended observer; and apply the active disturbance rejection controller to a marine power generation turbine.

[0157] In another exemplary embodiment, the feedback unit 802 is further configured to obtain a preset pole value; obtain a corresponding relationship between the pole value and a structural gain parameter of the feedback structure based on the transfer function; obtain the structural gain parameter of the feedback structure based on the corresponding relationship and the pole value; and obtain a control equation of the feedback structure based on the structural gain parameter:

[0158] u0=k p (z1-R)-k d z2

[0159] Among them, R is the input value of the input feedback structure, z1 and z2 are the observation values ​​output by the nonlinear expansion observer, and k p and k d is the structural gain parameter.

[0160] It should be noted that the nonlinear active disturbance rejection control device for a power generation steam turbine provided in the above-mentioned embodiment and the nonlinear active disturbance rejection control method for a power generation steam turbine provided in the above-mentioned embodiment are based on the same concept. The specific manner in which each module and unit performs operations has been described in detail in the method embodiment and will not be repeated here. In actual applications, the active disturbance rejection control device provided in the above-mentioned embodiment can, as needed, allocate the above-mentioned functions to different functional modules, i.e., divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0161] An embodiment of the present application also provides an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by one or more processors, the electronic device implements the nonlinear self-anti-disturbance control method for the power generation turbine provided in the above-mentioned embodiments.

[0162] Figure 9 The following is a schematic diagram showing the structure of a computer system suitable for implementing an electronic device according to an embodiment of the present application. Figure 9 The computer system 900 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0163] like Figure 9As shown, the computer system 900 includes a central processing unit (CPU) 901, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 902 or the program loaded from the storage part 908 into the random access memory (RAM) 903, such as executing the method in the above embodiment. Various programs and data required for system operation are also stored in the RAM 903. The CPU 901, ROM 902 and RAM 903 are connected to each other via a bus 904. An input / output (I / O) interface 905 is also connected to the bus 904.

[0164] The following components are connected to the I / O interface 905: an input section 906 including a keyboard, a mouse, and the like; an output section 907 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a speaker; a storage section 908 including a hard disk and the like; and a communication section 909 including a network interface card such as a LAN (Local Area Network) card or a modem. The communication section 909 performs communication processing via a network such as the Internet. A drive 910 is also connected to the I / O interface 905 as needed. Removable media 911, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, and the like, are installed in the drive 910 as needed, so that computer programs read therefrom can be installed into the storage section 908 as needed.

[0165] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 909, and / or installed from a removable medium 911. When the computer program is executed by the central processing unit (CPU) 901, the various functions defined in the system of the present application are executed.

[0166] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable computer program. This propagated data signal can take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. A computer program embodied on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0167] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. Among them, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, and the above-mentioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0168] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. In some cases, the names of these units do not constitute limitations on the units themselves.

[0169] Another aspect of the present application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned nonlinear active disturbance rejection control method for a power generation steam turbine. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist independently and not be incorporated into the electronic device.

[0170] Another aspect of the present application provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the nonlinear active disturbance rejection control method for a power generation steam turbine provided in each of the above-described embodiments.

[0171] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A nonlinear active disturbance rejection control method for a power generation steam turbine, characterized in that: The method comprises: Obtain the mathematical model of the steam turbine electro-hydraulic control system and determine the transfer function; constructing a control equation of a feedback structure based on the transfer function; The target extended state function of the nonlinear extended observer is constructed using logarithmic function and hyperbolic tangent function; The control equation and the target extended state function are applied to a marine power generation steam turbine to implement nonlinear active disturbance rejection control for the marine power generation steam turbine.

2. The method according to claim 1, characterized in that The target extended state function of the nonlinear extended observer constructed using the logarithmic function and the hyperbolic tangent function is:

3. The method according to claim 2, characterized in that The nonlinear extended observer is a third-order extended state observer; and applying the control equation and the target extended state function to a marine power generation steam turbine includes: Obtaining a first target state observation value, a second target state observation value, and a third target state observation value of the third-order nonlinear extended observer based on the target extended state function; applying the control equation to the feedback structure and applying the first target state observation, the second target state observation, and the third target state observation to the nonlinear extended observer; Applying the active disturbance rejection controller composed of the feedback structure and the nonlinear extended observer to a marine power generation steam turbine; Among them, the first target state observation value is z1, the derivative of z1 is z2+β1e, the second target state observation value is z2, the derivative of z2 is z3+β2falLT1(e), the third target state observation value is z3, the derivative of z3 is β3falLT2(e), e is the error value input into the nonlinear expansion observer, and β1, β2 and β3 are observer gain parameters.

4. The method according to claim 3, characterized in that The method of applying the active disturbance rejection controller composed of the feedback structure and the nonlinear extended observer to a marine power generation steam turbine includes: Get pre-configured system gain parameters; An active disturbance rejection controller is formed based on the feedback structure and the nonlinear extended observer applying the first target state observation value, the second target state observation value and the third target state observation value, and the active disturbance rejection controller is applied to a marine power generation turbine.

5. The method according to claim 1, wherein The control equation of the feedback structure constructed based on the transfer function includes: Get the preset extreme value; Acquire a correspondence between the pole value and a structural gain parameter of the feedback structure based on the transfer function; Obtaining a structural gain parameter of the feedback structure based on the corresponding relationship and the pole value; The control equation of the feedback structure is obtained based on the structural gain parameter: u0=k p (z1-R)-k d z2 Where R is the input value of the feedback structure, z1 and z2 are the observation values ​​output by the nonlinear expansion observer, and k p 、k d is the structural gain parameter.

6. A nonlinear active disturbance rejection controller, characterized in that: The nonlinear active disturbance rejection control method for a power generation steam turbine according to any one of claims 1 to 5 is applied, wherein the active disturbance rejection controller comprises a feedback structure and a nonlinear extended state observer, and the feedback structure is a proportional differential structure; The feedback structure applies a control equation determined by a transfer function of a mathematical model of a steam turbine electro-hydraulic control system, and the nonlinear extended state observer applies a target extended state function constructed by a logarithmic function and a hyperbolic tangent function; The feedback structure is connected to the control object, the nonlinear extended state observer is connected to the feedback structure and the control object, and the feedback structure performs feedback control on the input value based on the observation value output by the nonlinear extended state observer and transmits it to the control object.

7. The active disturbance rejection controller according to claim 6, characterized in that: The nonlinear extended state observer is a third-order extended state observer, comprising a first nonlinear function module, a second nonlinear function module and a third nonlinear function module; One end of the first nonlinear function module, the second nonlinear function module and the third nonlinear function module is connected to the input end of the nonlinear extended state observer, and the other end is connected to the corresponding integration module respectively to output the corresponding first target state observation value, second target state observation value and third target state observation value respectively.

8. A nonlinear active disturbance rejection control device for a power generation steam turbine, characterized in that: include: An acquisition unit, used for acquiring a mathematical model of the steam turbine electro-hydraulic control system and determining a transfer function; A feedback unit, configured to construct a control equation of a feedback structure based on the transfer function; A function construction unit, used for constructing a target extended state function of a nonlinear extended observer using a logarithmic function and a hyperbolic tangent function; An application unit is used to apply the control equation and the target expanded state function to a marine power generation steam turbine to implement nonlinear active disturbance rejection control for the marine power generation steam turbine.

9. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, enables the electronic device to implement the nonlinear active disturbance rejection control method for a power generation steam turbine as described in any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that Computer-readable instructions are stored thereon, and when the computer-readable instructions are executed by a processor of a computer, the computer is caused to execute the nonlinear active disturbance rejection control method for a power generation steam turbine according to any one of claims 1 to 5.

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