Non-linear active-disturbance-rejection control method for power generation steam turbine and related equipment

Abstract

The invention discloses a power generation steam turbine nonlinear active disturbance rejection control method and related equipment, and the method comprises the steps: obtaining a mathematical model of a steam turbine electro-hydraulic control system, and determining a transfer function; constructing a control equation of a feedback structure based on the transfer function; constructing a target expansion state function of the nonlinear expansion observer by using a logarithmic function and a hyperbolic tangent function; and the control equation and the target expansion state function are applied to the marine power generation steam turbine, so that nonlinear active-disturbance-rejection control of the marine power generation steam turbine is achieved. Through the logarithmic function and the hyperbolic tangent function, the novel nonlinear extended state observer is constructed, nonlinear factors are introduced, the dynamic characteristics of the nonlinear active-disturbance-rejection controller are better improved, the robust performance and control quality of the power generation steam turbine under the fault working conditions of large load step change, oil pressure abnormity and the like are improved, and the power generation efficiency of the power generation steam turbine is improved. And the method is of great significance in 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] As the heart of a ship, the stable and reliable operation of a steam turbine is the basis for safe navigation. The proportional-integral-differential (PID) algorithm is commonly used in steam turbine control strategies. This method is based on error and eliminates errors. It does not rely on an accurate mathematical model of the controlled object and is widely welcomed in engineering practice. The PID controller achieves satisfactory control results when the power grid is running smoothly and the power load does not change much.

[0003] However, unlike land-based steam turbines, marine steam turbines usually operate in an isolated grid and cannot simply be assumed to have a basically constant load. In addition, new ships that use all-electric propulsion often face situations such as drastic load changes, rapid load shedding, and frequent changes in operating conditions. At this time, the transfer function parameters of the system are greatly perturbed, and the traditional PID algorithm cannot adapt to the parameters, so the control effect no longer meets industrial needs. Traditional control algorithms have problems such as long adjustment time, poor anti-interference ability, and low robustness in the regulation and control of new all-electric propulsion ship power turbines. Summary of the invention

[0004] In order to solve the above technical problems, the 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 expanded 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 form a nonlinear self-disturbance rejection controller, which is applied to the marine power generation steam turbine to realize nonlinear self-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 self-disturbance rejection controller, thereby improving the control effect and control quality. Compared with linear self-disturbance rejection control, when the external load changes significantly, the nonlinear self-disturbance rejection control scheme of the present application can more effectively suppress the speed rise, improve the system's anti-disturbance capability, and realize 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 uses 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 uses 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 uses a target extended state function constructed by a logarithmic function and a hyperbolic tangent function;

[0014] The feedback structure is connected to a 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 an input value based on an observation value output by the nonlinear extended state observer and transmits the input value 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 a steam turbine electro-hydraulic control system and determining a transfer function;

[0017] A feedback unit, used for obtaining 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] The application unit is used for applying the control equation and the target expanded state function to a marine power generation steam turbine to realize 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 further provides a computer-readable storage medium having computer-readable instructions stored thereon, which, when executed by a processor of a computer, enables the computer to execute 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 a computer program, the computer program product or the computer program including computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the nonlinear auto-disturbance rejection control method for a power generation steam turbine provided in the above-mentioned various optional embodiments.

[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 drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. 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 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, 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 by the fal function and the nonlinear ESO set by the falLT function in the 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 It is a schematic diagram of the abnormal robustness curves of oil pressure 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] Fig. 9 It is a structural diagram of a computer system suitable for implementing an electronic device of an embodiment of the present application. DETAILED DESCRIPTION

[0034] Here, exemplary embodiments will be described in detail, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0035] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or 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 only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0037] The term "multiple" as used in this application refers to two or more than two. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, 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 self-interference rejection control method and device for a generator turbine, a nonlinear self-interference rejection controller, an electronic device, and a computer-readable storage medium, which mainly involve the nonlinear self-interference rejection control method technology of a generator turbine included in the turbine self-interference 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 self-disturbance rejection control method for a steam turbine generator according to an exemplary embodiment of the present application. 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, obtaining a mathematical model of a steam turbine electro-hydraulic control system and determining a transfer function.

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

[0042] The mathematical model of the steam turbine electro-hydraulic control system usually regards the steam turbine regulation system as a general object model, and divides the components in the system into transfer functions connected in series by various links according to their characteristics to construct a mathematical model. The regulation system of a marine steam turbine consists of multiple key components such as a controller, a servo amplifier, an electro-hydraulic converter, and an oil motor. The signal conversion process of the system is that the electrical signal sent by the controller is first converted into a hydraulic signal, which then drives the regulating valve to change the valve opening, adjust the steam intake, change the steam space pressure, and then control the speed. The rotor speed is finally converted into an electrical signal by the sensor and sent back to the controller to complete the closed loop.

[0043] In the embodiment provided by 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 anti-disturbance 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 It is a schematic diagram of the mathematical model of the steam turbine electro-hydraulic control system in an exemplary embodiment of the present application. In general, in order to facilitate the analysis and design of the control system, it can be regarded as a first-order system. If the input current of the speed controller is i and the valve position of the servo valve 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 equation (1) and equation (2):

[0045]

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

[0047] The working medium of a marine steam turbine is generally saturated wet steam, which has a low working pressure and a small enthalpy drop. Therefore, it is usually a single-cylinder structure and does not have a reheater. When the opening of the regulating valve changes, the pressure also changes, so the saturation of the water film changes, and part of the steam will precipitate from the water film or be absorbed by the water film, which makes its characteristics quite different from those of local thermal power steam turbine units.

[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 , heat transfer coefficient is α, heat transfer area is A, steam density is ρ, steam flow rate is q m , according to the energy conservation, heat transfer formula and mass conservation:

[0049]

[0050] Q = α(T w -T)A (4)

[0051]

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

[0053]

[0054] The gas state changes according to the multi-variable process. When the turbine operating condition is stable, the water film temperature T and the tube wall temperature T w The difference is not big, the heat transfer is negligible, and it can be obtained from formula (6):

[0055]

[0056] Consider the flow rate as a function of the 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 is considered to be related only to pressure, so q m1 =q m1 (s z ,p),q m2 =q m2 (p).

[0057] Within the turbine operating range, the specific heat c p Considered as a constant, di=c pdT. Substituting equation (7) for the pressure at the working point and the valve opening as p0, s z0 , expand it by Taylor, and finally get equation (8) and equation (9) after Laplace transformation and 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 steam turbine, T b Because the time constant is increased due to the water film, the time constant of the marine steam turbine is larger than that of the thermal power unit.

[0064] The nuclear steam turbine rotor equation is not much different. According to Newton's second law and Taylor expansion expression near the working 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 of 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: construct 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 part of the ADRC. It estimates the state variables of the system through the input and output of the system and is responsible for converting the standard control system shown in the following equation (12) into an integral series system of equation (13), where x represents the system state, f represents the nonlinear factor, u represents the input, and w represents the disturbance. The nonlinear factors, model uncertainties, and external disturbances are uniformly regarded as the total disturbance and used as the high-order derivatives of the system, and active feedforward compensation is performed through the extended state observer.

[0069]

[0070]

[0071] Although the use of linear functions in the expanded observer facilitates system analysis and parameter tuning, the 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 auto-disturbance rejection controller to implement a nonlinear auto-disturbance rejection control method for a power generation steam turbine.

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

[0074] Active Disturbance Rejection Control (ADRC) is generally composed of a tracking differentiator, an extended state observer, and a linear or nonlinear feedback structure. The tracking differentiator is responsible for softening the input signal to resolve the contradiction between rapidity and accuracy. In the design of linear ADRC, in order to facilitate the dynamic characteristics analysis of the system, the tracking differentiator is usually omitted and simplified to a combination of a linear extended observer and a PD (Proportional-Derivative) linear error feedback control rate.

[0075] In the embodiments provided in the present application, a nonlinear auto-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 generator steam turbine to implement nonlinear auto-disturbance rejection control for the marine generator 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 form a nonlinear self-disturbance control controller, which is applied to the marine generator steam turbine to realize nonlinear self-disturbance control for the marine generator steam turbine. The present application introduces nonlinear factors to better improve the dynamic characteristics of the nonlinear self-disturbance control controller, thereby improving the control effect and control quality. Compared with linear self-disturbance control, when the external load changes significantly, the nonlinear self-disturbance control scheme of the present application can more effectively suppress the speed rise, improve the system's primary frequency modulation capability, and achieve stable control of the marine generator steam turbine.

[0077] In the ADRC, 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. At present, the parameter tuning of this type of nonlinear ADRC is mainly based on experience. The parameters in the fal(x) function are mainly α and δ. The parameter α mainly determines the growth rate of the fal(x) output away from the origin. The larger the α, the greater the output growth rate. δ is responsible for the size of the linear interval and the slope of the linear function. However, when the linear interval is introduced at the origin, when the error is small enough, the error converges from the power function to the linear convergence, and the function cannot smoothly transition at the segmentation point, and there is an overshoot phenomenon.

[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 by 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, tanh(bx) is mainly used to realize the idea of ​​small error and large gain.

[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 thereof can be proved separately.

[0084] First, the stability of the logarithmic part is proved. 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 derivatives with respect to e1 and e2 are:

[0089]

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

[0091]

[0092] When β1>0, The observer converges, and the same is true 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, and 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 extended 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 extended 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] The active disturbance rejection controller composed of feedback structure and nonlinear extended observer is applied to 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 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 the stability of the system. 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 the present application, the specific steps of applying the active disturbance rejection controller composed of the feedback structure and the nonlinear expansion observer to the marine power generation steam turbine in the corresponding above embodiment may include:

[0109] Get pre-configured system gain parameters;

[0110] An active disturbance rejection controller is formed based on a feedback structure and a nonlinear extended observer using a first target state observation value, a second target state observation value and a third target state observation value, and the active disturbance rejection controller 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-mentioned embodiments to implement nonlinear active disturbance rejection control for the marine steam turbine, improve the control effect, and contribute to the improvement of control quality.

[0112] In an exemplary embodiment provided by the present 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 the correspondence between the pole value and the structural gain parameter 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 is, the better the control effect is. 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 transfer relationship between data signals. The nonlinear anti-disturbance controller in which the feedback structure is located 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 pole 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 the control equation determined by the transfer function of the mathematical model of the steam turbine electro-hydraulic control system, and the nonlinear extended state observer 320 applies the target extended state function constructed by the logarithmic function and the 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 denoted as z1, The observation of the state is recorded as z2, and the observation of the disturbance is recorded as z3. When the nonlinear ESO estimates the system state and the disturbance, this information will be used for feedback control through the floating loss structure. The nonlinear active disturbance rejection controller calculates the control input based on these estimates to achieve accurate 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 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), 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 for the conventional ESO using the fall function and the nonlinear ESO using the fallT function provided in the embodiment of the present application is:

[0131]

[0132] The error system of ESO constructed by fal function and nonlinear ESO constructed 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 steady-state error e1 of the system decreases in the form of a power function as the parameter β2 increases, so the efficiency is much higher than the linear observer error e1 = w / β2. However, for power functions such as those 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, a high-slope linear function is introduced near the origin to alleviate it, which leads to a decrease in ESO performance.

[0135] When the system enters a steady state, assuming that 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 between the ESO set by the fall function and the nonlinear ESO set by 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 anti-disturbance capability and robustness of the traditional linear anti-disturbance controller, the nonlinear anti-disturbance controller (LTADRC) and the PID controller in the case of severe load rejection and abnormal oil pressure of the oil motor. The rated speed of the steam turbine is normalized to 1, the disturbance is simulated by introducing a negative step signal at the 10th second of stable operation to simulate the load rejection of the steam turbine, and the abnormal oil pressure is realized by increasing the time constant of the oil motor link.

[0140] The overshoot and adjustment time of the three control strategies for the turbine when shedding different loads are summarized in Tables 1 and 2, where the adjustment time is defined as the time taken to recover to the rated speed within the 0.5% error band after the introduction of disturbance, and the overshoot is defined as the deviation between the peak speed and the rated speed. It can be seen that the PID controller, linear anti-disturbance controller and the anti-disturbance controller designed in this paper can suppress the speed within 3% error when the load is suddenly unloaded, and the adjustment time is less than 3s, meeting the design indicators, and the LTADRC overshoot and adjustment time are the least. 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 the linear active disturbance rejection control strategy is used to deal with the severe load rejection of the unit, the speed cannot be smoothly restored to the rated speed. The main reason is that when a low-order linear active disturbance rejection control is used to control a high-order system, the extended state observer cannot accurately track the disturbance due to its structural limitations, resulting in vibration. In this case, the order of the extended state observer can usually be appropriately increased to make more use of the known information of the system. However, by introducing appropriate nonlinear factors, its anti-disturbance effect is better than that of the linear active disturbance rejection control strategy at the same order.

[0146] Robustness is another important indicator for verifying the controller, which describes the ability of the system to maintain stable control when the dynamic characteristics change. In the regulation and control system of the ship power turbine, the abnormal oil pressure of the oil motor is a typical fault, which is mainly manifested as the change of the time constant of the oil motor link. When the time constant of the oil motor is reduced and the cutoff frequency is shifted to the right, it can better respond to the control signal and increase the stability margin. For this reason, the time constant of the oil motor transfer function is doubled to simulate the abnormal oil pressure, and a negative 0.15 transition signal is introduced when the system is running stably for 10s 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 ADRC and the nonlinear ADRC vibrate. The overshoot of LADRC is 0.8%, while the overshoot of LTADRC is 4.1%. Figure 7 It is a schematic diagram of the abnormal robustness curves of oil pressure of different controllers during the simulation experiment. The time for LADRC to recover to the 0.5% error band is about 2.5 seconds, while LTADRC takes 3.5 seconds. Although linear control seems to be better than nonlinear control in terms of overshoot and recovery time, the vibration frequency of nonlinear control is significantly lower than that of linear control in terms of vibration frequency, indicating its advantage in robustness.

[0148] It can be seen that, in the embodiment provided by the present application, the nonlinear anti-disturbance control controller is more effective in suppressing the speed surge and improving the system's primary frequency modulation capability when the external load changes significantly compared to the linear anti-disturbance control. In addition, the simulation verification of simulating oil pressure failure by changing the time constant of the oil motor link shows that the nonlinear anti-disturbance control controller provided by the linear anti-disturbance control itself has stronger robustness.

[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 comprises:

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

[0151] A feedback unit 802, used for obtaining a control equation of a feedback structure based on a 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 used to apply the control equation and the target expanded state function to the marine power generation steam turbine to implement nonlinear active disturbance rejection control for the marine power generation steam turbine.

[0154] The device applies the nonlinear auto-disturbance rejection control method for a power generation steam turbine provided by the present application, and constructs a new type of nonlinear extended state observer by using a logarithmic function and a hyperbolic tangent function through a function construction unit 803, and uses a feedback unit 802 to determine the control equation of the feedback structure based on the mathematical model of the steam turbine electro-hydraulic control system, and an application unit 804 applies the feedback structure of the above control equation and the nonlinear extended observer using the above target extended state function to form a nonlinear auto-disturbance rejection controller, which is applied to a marine power generation steam turbine to realize nonlinear auto-disturbance rejection control for a marine power generation steam turbine. The present application introduces nonlinear factors to better improve the dynamic characteristics of the nonlinear auto-disturbance rejection controller, and improves 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 rise, improve the system's ability to adjust the frequency once, and realize 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 also used to obtain the first target state observation value, the second target state observation value and the 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 composed 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 used to obtain a pre-configured system gain parameter; form an active disturbance rejection controller based on the system gain parameter, feedback structure and nonlinear expansion 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 used 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 auto-disturbance rejection control device for a power generation steam turbine provided in the above embodiment and the nonlinear auto-disturbance rejection control method for a power generation steam turbine provided in the above embodiment belong to the same concept, wherein the specific manner in which each module and unit performs the operation has been described in detail in the method embodiment and will not be repeated here. In practical applications, the auto-disturbance rejection control device provided in the above embodiment can allocate the above functions to different functional modules as needed, that is, 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, and when the one or more programs are executed by one or more processors, the electronic device implements the nonlinear self-disturbance rejection control method of the power generation turbine provided in the above-mentioned embodiments.

[0162] Fig. 9 The structure diagram of the computer system suitable for implementing the electronic device of the embodiment of the present application is shown. It should be noted that: Fig. 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 Fig. 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 to the random access memory (RAM) 903, such as executing the method in the above embodiment. In the RAM 903, various programs and data required for system operation are also stored. The CPU 901, ROM 902 and RAM 903 are connected to each other through 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, etc.; an output section 907 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 908 including a hard disk, etc.; and a communication section 909 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. 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. A removable medium 911, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 910 as needed so that a computer program read therefrom is 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 through a communication section 909, and / or installed from a removable medium 911. When the computer program is executed by a central processing unit (CPU) 901, 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 embodiment 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 may include a data signal propagated in a baseband or as part of a carrier wave, wherein a computer-readable computer program is carried. 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, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. A computer program contained on a computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0167] The flowchart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. Wherein, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order 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 a 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. The names of these units do not, in some cases, constitute limitations on the units themselves.

[0169] Another aspect of the present application also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the nonlinear self-disturbance rejection control method for a power generation steam turbine as described above is implemented. The computer-readable storage medium may be included in the electronic device described in the above embodiment, or may exist independently without being assembled into the electronic device.

[0170] Another aspect of the present application also provides a computer program product or a computer program, the computer program product or the computer program includes computer instructions, the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the nonlinear active disturbance rejection control method for the power generation steam turbine provided in the above-mentioned various embodiments.

[0171] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present application should be included in the protection scope 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 expanded 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; the control equation and the target extended state function are applied to a marine power generation steam turbine, including: 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, 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, 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 expansion observer to a marine power generation steam turbine comprises: Get pre-configured system gain parameters; An active disturbance rejection controller is formed based on the feedback structure and the nonlinear extended observer using 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, characterized in that: The control equation of the feedback structure obtained 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 uses 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 uses a target extended state function constructed by a logarithmic function and a hyperbolic tangent function; The feedback structure is connected to a 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 an input value based on an observation value output by the nonlinear extended state observer and transmits the input value 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, including 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 a steam turbine electro-hydraulic control system and determining a transfer function; A feedback unit, used for constructing 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; The application unit is used for applying the control equation and the target expanded state function to a marine power generation steam turbine to realize 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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