Pressure control method and device for once-through steam generator

Abstract

The embodiment of the invention provides a once-through steam generator pressure control method and device, and relates to the technical field of nuclear power, and the method comprises the steps: firstly obtaining a system state space model of an OTSG of a nuclear power station, and then introducing interference observation to carry out the online estimation of the external disturbance of the OTSG, and obtaining a system state space model of the OTSG; and then designing a robust sliding mode controller to carry out sliding mode control on the steam pressure of the OTSG. By adopting the technical scheme provided by the embodiment of the invention, the steam pressure of the OTSG can be efficiently and reliably controlled.

Description

Technical Field

[0001] The present application relates to the field of nuclear power technology, and in particular, to a method and device for controlling the pressure of a once-through steam generator. Background Art

[0002] During the actual operation of the once-through steam generator (OTSG) in a nuclear power plant, the steam pressure is very susceptible to the interference of changes in the steam flow rate at the OTSG outlet. In related technologies, sliding mode control can be used to improve the anti-interference ability of the system. However, when using the traditional sliding mode control method, a large switching gain is required to effectively suppress the external interference on the steam pressure of the OTSG, and an excessive switching gain will cause chattering of the steam pressure of the OTSG. That is, it is difficult for related technologies to control the steam pressure of the OTSG efficiently and reliably. Summary of the Invention

[0003] The main objective of the embodiments of the present application is to propose a method and device for controlling the pressure of a once-through steam generator, aiming to control the steam pressure of the OTSG efficiently and reliably.

[0004] To achieve the above objective, a first aspect of the embodiments of the present application proposes a method for controlling the pressure of a once-through steam generator, the method including:

[0005] Obtaining the system state space model of the once-through steam generator of the nuclear power plant;

[0006] Performing online estimation on the external disturbance of the once-through steam generator to obtain the external disturbance estimation data of the once-through steam generator;

[0007] Performing sliding mode control on the steam pressure of the once-through steam generator based on the system state space model and the external disturbance estimation data.

[0008] In some embodiments, the external disturbance of the once-through steam generator includes: the disturbance of the outlet steam flow rate received by the once-through steam generator;

[0009] The performing online estimation on the external disturbance of the once-through steam generator to obtain the external disturbance estimation data of the once-through steam generator includes:

[0010] Performing online estimation on the disturbance of the outlet steam flow rate received by the once-through steam generator based on a preset disturbance observer to obtain the external disturbance estimation data of the once-through steam generator.

[0011] In some embodiments, the method further includes:

[0012] Obtain the system state variables of the once-through steam generator, and obtain the disturbance quantity of the outlet steam flow of the once-through steam generator;

[0013] Based on the system state variables, the disturbance quantity of the outlet steam flow, and the influence of sliding mode control on the steam pressure of the once-through steam generator on disturbance observation, design the disturbance observer.

[0014] In some embodiments, the sliding mode control of the steam pressure of the once-through steam generator based on the system state space model and the external disturbance estimation data includes:

[0015] Determine an integral terminal sliding mode controller based on the system state space model, the external disturbance estimation data, and a preset sliding mode surface;

[0016] Perform sliding mode control on the steam pressure of the once-through steam generator through the integral terminal sliding mode controller.

[0017] In some embodiments, the method further includes:

[0018] Determine the system consistency error based on the system state variables of the once-through steam generator;

[0019] Sum the integral of the system consistency error and the system state variables of the once-through steam generator to obtain the sliding mode surface when controlling the steam pressure of the once-through steam generator.

[0020] In some embodiments, the performing sliding mode control on the steam pressure of the once-through steam generator through the integral terminal sliding mode controller includes:

[0021] Output control parameters based on the system state variables of the once-through steam generator through the integral terminal sliding mode controller;

[0022] Drive the once-through steam generator through the actuator of the once-through steam generator according to the control parameters.

[0023] In some embodiments, the method further includes:

[0024] Determine an integral terminal sliding mode controller based on the disturbance observer based on the system state variables of the once-through steam generator and the external disturbance estimation data, where the disturbance observer is a disturbance observer that performs online estimation on the external disturbance of the once-through steam generator to obtain the external disturbance estimation data;

[0025] Perform sliding mode control on the steam pressure of the once-through steam generator through the integral terminal sliding mode controller.

[0026] In some of these embodiments, obtaining the system state space model of the once-through steam generator of a nuclear power plant includes:

[0027] Constructing the system state space model of the once-through steam generator based on the system state variables of the once-through steam generator of the nuclear power plant.

[0028] In some of these embodiments, the system state variables of the once-through steam generator include: the input system state variables of the once-through steam generator and the output system state variables of the once-through steam generator; wherein, the input system state variables include: the primary side inlet temperature, the secondary side inlet feed water temperature, the secondary side inlet feed water flow rate, and the secondary side outlet steam flow rate, and the output system state variables include: the primary side outlet temperature, the secondary side outlet steam temperature, and the secondary side steam pressure.

[0029] To achieve the above object, a second aspect of the embodiments of the present application provides a once-through steam generator pressure control device, and the device includes:

[0030] An acquisition module, configured to acquire the system state space model of the once-through steam generator of a nuclear power plant;

[0031] An interference estimation module, configured to perform online estimation on the external disturbance of the once-through steam generator to obtain the external disturbance estimation data of the once-through steam generator;

[0032] A control module, configured to perform sliding mode control on the steam pressure of the once-through steam generator based on the system state space model and the external disturbance estimation data.

[0033] To achieve the above object, a third aspect of the embodiments of the present application provides a computer device, and the computer device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, each step of the method provided in the first aspect above is implemented.

[0034] To achieve the above object, a fourth aspect of the embodiments of the present application provides a computer-readable storage medium, and the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, each step of the method provided in the first aspect above is implemented.

[0035] To achieve the above object, a fifth aspect of the embodiments of the present application provides a computer program product, and the computer program product includes a computer program. When the computer program is executed by a processor, each step of the method provided in the first aspect above is implemented.

[0036] The pressure control method for a once-through steam generator, the pressure control device for a once-through steam generator, a computer device, a computer-readable storage medium, and a computer program product proposed in the embodiments of the present application obtain the system state space model of the once-through steam generator of a nuclear power plant; perform online estimation on the external disturbance of the once-through steam generator to obtain the estimated data of the external disturbance of the once-through steam generator; and perform sliding mode control on the steam pressure of the once-through steam generator based on the system state space model and the estimated data of the external disturbance.

[0037] That is to say, the embodiments of the present application first obtain the system state space model of the once-through steam generator (OTSG) of a nuclear power plant, then introduce disturbance observation to perform online estimation on the external disturbance received by the OTSG to obtain the estimated data of the external disturbance of the OTSG, and then combine with the robust sliding mode control algorithm to perform sliding mode control on the steam pressure of the OTSG based on the system state space model and the estimated data of the external disturbance of the OTSG. In this way, the embodiments of the present application can quickly stabilize the steam pressure of the OTSG near the set value during the operation of the OTSG, and avoid the steam pressure of the OTSG from generating chattering phenomena caused by external disturbances, thereby performing efficient and reliable control on the steam pressure of the OTSG. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic flowchart of the steps of the pressure control method for a once-through steam generator provided by the embodiments of the present application in some embodiments;

[0039] Figure 2 It is a schematic structural diagram of the OTSG involved in the pressure control method for a once-through steam generator provided by the embodiments of the present application in some embodiments;

[0040] Figure 3 is Figure 1 a schematic flowchart of the detailed steps of step S103 in;

[0041] Figure 4 is Figure 3 a schematic flowchart of the detailed steps of step S302 in;

[0042] Figure 5 It is a schematic system architecture diagram of the pressure control of the once-through steam generator for the OTSG involved in the pressure control method for a once-through steam generator provided by the embodiments of the present application in some embodiments;

[0043] Figure 6 It is a schematic diagram of the simulation results involved in the steam control method provided by the embodiments of the present application in some embodiments;

[0044] Figure 7Schematic structural framework diagram of the DC steam generator pressure control device provided by the embodiments of the present application in some embodiments;

[0045] Figure 8 Internal structural schematic diagram of the computer device provided by the embodiments of the present application. Detailed implementation manners

[0046] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] It should be noted that although functional module division is performed in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different module division in the device or a different order in the flowchart. Terms such as "first" and "second" in the specification, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0049] Before introducing the embodiments of the present application, relevant technical terms involved in the embodiments of the present application will be briefly introduced here.

[0050] Steam generator of nuclear power plant.

[0051] The steam generator of a nuclear power plant is a core device of the nuclear island. The steam generator connects the primary and secondary loops, transfers the heat generated by the reactor to the feed water on the secondary side. The safe and efficient operation of the steam generator is directly related to the power and efficiency of the nuclear power plant. Therefore, precise steam pressure control of the steam generator is the key to ensuring the safe operation of the steam generator and ensuring the steam quality at the outlet of the steam generator.

[0052] Once-through steam generator OTSG.

[0053] The OTSG is a steam generator in a nuclear power plant. The OTSG is a complex thermal system with non-linearity and large time delay. During the operation of the OTSG, due to the complex thermal process inside the OTSG, and at the same time, there are external disturbances (also known as "interferences") such as load condition changes, equipment aging, and noise. These factors may all lead to phenomena such as parameter drift of the controlled object when controlling the steam pressure of the OTSG. Especially when the OTSG is disturbed by a large steam flow rate, the system parameters of the OTSG change in a wide range, and there may be a situation where the OTSG is damaged due to overpressure or a safety accident is triggered, thus having a great impact on the normal operation of the reactor. Therefore, it has certain value to study the pressure control of the OTSG under large steam flow rate disturbances.

[0054] On the one hand, the water storage capacity on the secondary side of the OTSG is small, and the heat storage capacity is poor. The change of the external load has a very significant impact on the steam pressure of the OTSG. Moreover, there are complex processes of subcooling, evaporation, and superheating in the secondary loop fluid, and the lengths of each section will also change at any time during the dynamic process, resulting in the translation of the boundary line between different sections and the drastic change of the outlet steam temperature. During the actual operation of the OTSG, if there are large pressure fluctuations, it is easy to cause accidents such as rupture of the secondary loop pipes, damaging the service life of the OTSG. During the process of controlling the steam pressure of the OTSG, various uncertainties destroy the stability and static and dynamic performance of the OTSG system. In order to overcome the influence of uncertain factors on the system quality, the control of the steam pressure of the OTSG must be robust.

[0055] Sliding mode control.

[0056] Sliding mode control is widely used due to its characteristics of fast response, no need for online system identification, and insensitivity to parameter changes and disturbances. Especially, the integral terminal sliding mode control has good convergence in finite time, high tracking accuracy, and small interference influence, and has become one of the most widely used finite-time control methods.

[0057] Next, the overall concept of the DC steam generator pressure control method provided by the embodiments of the present application will be further described.

[0058] Aiming at the problem that it is difficult to efficiently and reliably control the steam pressure of the OTSG in the related art, the embodiments of the present application provide a DC steam generator pressure control method, device, equipment, storage medium, and program product. By obtaining the system state space model of the DC steam generator of a nuclear power plant; online estimating the external disturbance of the DC steam generator to obtain the external disturbance estimation data of the DC steam generator; and performing sliding mode control on the steam pressure of the DC steam generator based on the system state space model and the external disturbance estimation data.

[0059] That is to say, in the embodiment of the present application, first, a system state space model of the once-through steam generator (OTSG) of a nuclear power plant is obtained. Then, a disturbance observer is introduced to estimate the external disturbance received by the OTSG online to obtain the estimated data of the external disturbance of the OTSG. Next, in combination with the robust sliding mode control algorithm, based on the system state space model of the OTSG and the estimated data of the external disturbance, the sliding mode control is performed on the steam pressure of the OTSG. In this way, the embodiment of the present application can efficiently and reliably control the steam pressure of the OTSG, so that during the operation of the OTSG, the steam pressure of the OTSG can be quickly stabilized near the set value, and the phenomenon that the steam pressure of the OTSG is caused to vibrate due to the external disturbance received by the OTSG can be avoided.

[0060] It should be understood that the once-through steam generator pressure control method provided by the embodiment of the present application can be applied to a terminal, or to a server side, or can also be software running on a terminal or a server side. In some embodiments, the terminal can be a smart phone, a tablet computer, a notebook computer, a desktop computer, etc.; the server side can be configured as an independent physical server, or can be configured as a server cluster or a distributed system composed of multiple physical servers, or can also be configured as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application for implementing the once-through steam generator pressure control method, etc., but is not limited to the above forms.

[0061] Alternatively, the present application can also be used in many general-purpose or special-purpose computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet-type devices, multi-processor systems, microprocessor-based systems, set-top boxes, programmable consumer computer devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and so on. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types.

[0062] For the convenience of understanding and elaboration, in the following text, the implementation of the once-through steam generator pressure control method provided by the embodiment of the present application in a terminal device is taken as an example to describe the present application in detail. The implementation of the once-through steam generator pressure control method provided by the embodiment of the present application in any of the above forms of the subject can refer to the process of the terminal device applying the once-through steam generator pressure control method to control the once-through steam generator pressure described later.

[0063] Please refer to Figure 1 , Figure 1Schematic diagram of the steps of the DC steam generator pressure control method provided by the embodiments of the present application in some embodiments. It should be understood that although Figure 1 shows the execution order of some method steps, based on different design requirements of actual applications, the DC steam generator pressure control method provided by the embodiments of the present application can of course adopt an execution order different from that shown in the figure. That is, Figure 1 the order of the shown method steps does not constitute a limitation on the execution logic order of the DC steam generator pressure control method provided by the embodiments of the present application, and any reasonable changes based on Figure 1 the order of the shown method steps should be included within the protection scope of the DC steam generator pressure control method provided by the embodiments of the present application.

[0064] As Figure 1 shown, in some embodiments, the DC steam generator pressure control method provided by the embodiments of the present application may include steps S101 to S103.

[0065] Step S101: Obtain the system state space model of the DC steam generator of the nuclear power plant.

[0066] When the terminal device performs pressure control on the DC steam generator OTSG of the nuclear power plant, it first obtains the pre-constructed system state space model of the DC steam generator OTSG.

[0067] It should be noted that the terminal device can pre-construct the system state space model of the OTSG based on the system state variables of the OTSG, and then store the system state space model locally for subsequent calls at any time. Or, the terminal device can also, based on the communication connection with other terminal devices, send a model acquisition request to other terminal devices when pressure control of the OTSG is required, so as to receive the system state space model of the OTSG fed back by other terminal devices. Other terminal devices pre-construct the system state space model of the OTSG based on the system state variables of the OTSG.

[0068] In some embodiments, the above step S101 may include the following steps:

[0069] Construct the system state space model of the DC steam generator based on the system state variables of the DC steam generator of the nuclear power plant.

[0070] In addition to obtaining the pre-constructed system state space model of the OTSG, the terminal device can also, during the operation of the DC steam generator OTSG of the nuclear power plant, collect and obtain the system state variables of the OTSG in real time through the sensors of the OTSG, so as to construct the system model (state space model) of the OTSG based on the system state variables.

[0071] In some embodiments, the system state variables include: the input system state variables of the once-through steam generator and the output system state variables of the once-through steam generator; wherein, the input system state variables include: the primary side inlet temperature, the secondary side inlet feed water temperature, the secondary side inlet feed water flow rate, and the secondary side outlet steam flow rate, and the output system state variables include: the primary side outlet temperature, the secondary side outlet steam temperature, and the secondary side steam pressure.

[0072] Exemplarily, as Figure 2 shown in the OTSG structure, from the interface boundary conditions of the OTSG with one side of the coolant and the steam turbine, the OTSG can be regarded as a steam pressure system with four inputs and three outputs. Based on this, when the terminal device obtains the system state variables of the OTSG through the sensors of the OTSG, it can specifically obtain four input system state variables, namely: the primary side inlet temperature, the secondary side inlet feed water temperature, the secondary side inlet feed water flow rate, and the secondary side outlet steam flow rate, and obtain three output system state variables, namely: the primary side outlet temperature, the secondary side outlet steam temperature, and the secondary side steam pressure.

[0073] After the terminal device collects and obtains the four input system state variables (the primary side inlet temperature, the secondary side inlet feed water temperature, the secondary side inlet feed water flow rate, and the secondary side outlet steam flow rate) and the three output system state variables (the primary side outlet temperature, the secondary side outlet steam temperature, and the secondary side steam pressure) of the OTSG through the sensors of the OTSG, based on the linearized form of the OTSG system model, the state space model of the OTSG is constructed as follows:

[0074]

[0075] Among them, x(t) is the system state variable x(t) = [x 1 (t), x 2 (t), x 3 (t), x 4 (t)] T ; is the first derivative of the system state variable x(t); u(t) is the integral terminal sliding mode controller based on the disturbance observer, which here represents the influence of the integral terminal sliding mode controller on the steam pressure control of the OTSG on the system state variable x(t) of the OTSG; d(t) is the disturbance amount of the outlet steam flow rate; y(t) is the steam pressure of the OTSG; A(p), B(p), C(p), and D(p) are system matrices.

[0076] Step S102: Perform online estimation on the external disturbance of the once-through steam generator to obtain the external disturbance estimation data of the once-through steam generator.

[0077] The terminal device also introduces disturbance observation. While or after obtaining the system state variables of the OTSG, it online estimates the external disturbances suffered by the OTSG, so as to obtain the external disturbance estimation data of the OTSG.

[0078] Step S103: Based on the system state space model and the external disturbance estimation data, perform sliding mode control on the steam pressure of the once-through steam generator.

[0079] When the terminal device obtains the system state space model of the OTSG, and online estimates the external disturbances suffered by the OTSG through introducing disturbance observation to obtain the external disturbance estimation data of the OTSG, combined with the robust sliding mode control algorithm, based on the system state space model and the external disturbance estimation data of the OTSG, perform sliding mode control on the steam pressure of the OTSG.

[0080] In the embodiments of the present application, the terminal device first obtains the system state space model of the once-through steam generator (OTSG) of a nuclear power plant, then introduces disturbance observation to online estimate the external disturbances suffered by the OTSG to obtain the external disturbance estimation data of the OTSG, and then combines the robust sliding mode control algorithm to perform sliding mode control on the steam pressure of the OTSG based on the system state space model and the external disturbance estimation data of the OTSG.

[0081] In this way, the embodiments of the present application can quickly stabilize the steam pressure of the OTSG near the set value during the operation of the OTSG, and avoid the steam pressure of the OTSG from generating chattering phenomena caused by external disturbances suffered by the OTSG, so as to perform efficient and reliable control on the steam pressure of the OTSG.

[0082] In some embodiments, the external disturbances of the once-through steam generator include: the outlet steam flow disturbance suffered by the once-through steam generator. Based on this, the above step S102: Online estimate the external disturbances of the once-through steam generator to obtain the external disturbance estimation data of the once-through steam generator, may include:

[0083] Based on a preset disturbance observer, online estimate the outlet steam flow disturbance suffered by the once-through steam generator to obtain the external disturbance estimation data of the once-through steam generator.

[0084] It should be noted that the preset disturbance observer can be designed based on the system state variables of the once-through steam generator, the disturbance quantity of the outlet steam flow, and the influence of sliding mode control on the steam pressure of the once-through steam generator on disturbance observation.

[0085] When the terminal device estimates the disturbance of the outlet steam flow received by the OTSG online by introducing disturbance observation, it calls a pre-designed disturbance observer to estimate the disturbance of the outlet steam flow received by the OTSG online, so as to obtain the estimated data of the external disturbance of the OTSG.

[0086] In some embodiments, the DC steam generator pressure control method provided by the embodiments of the present application may further include the following steps:

[0087] Obtain the system state variables of the DC steam generator, and obtain the disturbance amount of the outlet steam flow of the DC steam generator;

[0088] Based on the system state variables, the disturbance amount of the outlet steam flow, and the influence of sliding mode control on the steam pressure of the DC steam generator on disturbance observation, design the disturbance observer.

[0089] The terminal device can pre-design a disturbance observer, and then when estimating the external disturbance of the OTSG online, call the disturbance observer to estimate the disturbance of the outlet steam flow received by the OTSG online. That is, during the operation of the OTSG by the terminal device, the system state variables of the OTSG are collected in real time through the sensors of the OTSG, and the disturbance amount of the outlet steam flow of the OTSG is collected in real time. Then, combining the system state variables, the disturbance amount of the outlet steam flow collected in real time, and the influence of sliding mode control on the steam pressure of the OTSG on disturbance observation, design the disturbance observer.

[0090] Exemplarily, in order to estimate the external disturbance (outlet steam flow disturbance) received by the OTSG online, the terminal device can pre-design a disturbance observer as follows:

[0091]

[0092] Among them, is the estimated value of the disturbance amount d(t) of the outlet steam flow received by the OTSG (that is, the estimated data of the external disturbance), and the disturbance error is the auxiliary system state of the disturbance observer; ξ is a design parameter, and specifically a positive constant (a constant greater than zero); x(t) is the system state variable x(t)=[x 1 (t),x 2 (t),x 3 (t),x 4 (t)] T ; is the first derivative of the auxiliary system state of the disturbance observer; A(t), B(t), C(t), C-1 (t) is the system matrix; u(t) is the integral terminal sliding mode controller based on the disturbance observer, which represents that the integral terminal sliding mode controller controls the steam pressure of the OTSG and affects the online estimation of the disturbance observer on the outlet steam flow disturbance received by the OTSG.

[0093] In this embodiment, the terminal device pre - designs the above - shown disturbance observer based on the system state variables of the OTSG and the execution result of controlling the steam pressure of the OTSG, so as to online estimate the outlet steam flow disturbance received by the OTSG through this disturbance observer. Then, combined with the robust sliding mode control algorithm, an integral terminal sliding mode controller based on the disturbance observer can be designed to control the steam pressure of the OTSG. In this way, the terminal device can quickly stabilize the steam pressure of the OTSG near the set value during the operation of the OTSG, solve the problem of the disturbance of the outlet steam flow to the steam pressure of the OTSG, and avoid the chattering phenomenon of the steam pressure of the OTSG.

[0094] In some embodiments, the terminal device can first construct the system state - space model of the OTSG according to the obtained system parameters (system state variables) of the OTSG and define the consistency error of the system state variables; then, the terminal device introduces a disturbance observer to estimate the outlet steam flow disturbance received by the OTSG, and combined with the robust sliding mode control algorithm, designs an integral terminal sliding mode controller based on the disturbance observer to control the steam pressure of the OTSG.

[0095] Please refer to Figure 3 , Figure 3 is Figure 1 the detailed step - flow schematic diagram of step S103 in

[0096] As Figure 3 shown, in some embodiments, the above - mentioned step S103: performing sliding mode control on the steam pressure of the once - through steam generator based on the system state variables and the external disturbance estimation data may include steps S301 to S302 as follows.

[0097] Step S301: Determine the integral terminal sliding mode controller based on the system state - space model, the external disturbance estimation data, and the preset sliding surface.

[0098] After the terminal device obtains the system state - space model of the OTSG and online estimates the external disturbance received by the OTSG through introducing a disturbance observer to obtain the external disturbance estimation data of the OTSG, it can design an integral terminal sliding mode controller based on the disturbance observer by combining the sliding mode control algorithm based on this system state - space model, external disturbance estimation data, and preset sliding surface.

[0099] It should be noted that the principle of sliding mode control for the steam pressure of the OTSG is to ensure that the system state (steam pressure state) of the OTSG can be driven to the sliding mode surface by the designed integral terminal sliding mode controller within a finite time and move along the sliding mode surface to the desired equilibrium point. Therefore, the terminal device can pre-design a sliding mode surface to make the sliding mode motion determined by the sliding mode surface asymptotically stable and have good dynamic performance. In this way, when subsequent steam pressure control of the OTSG is performed based on the integral terminal sliding mode controller, the steam pressure of the OTSG can be quickly stabilized near the set value and the phenomenon of chattering of the steam pressure of the OTSG caused by external disturbances can be avoided.

[0100] In some embodiments, the DC steam generator pressure control method provided by the embodiments of the present application may further include the following steps:

[0101] Determine the system consistency error based on the system state variables of the DC steam generator;

[0102] Sum the integral of the system consistency error and the system state variables of the DC steam generator to obtain the sliding mode surface for controlling the steam pressure of the DC steam generator.

[0103] After or simultaneously building the state space model of the OTSG, the terminal device can define the system consistency error e for steam pressure control of the OTSG based on the system state variables of the OTSG as:

[0104] e = x(t) - x d (t)

[0105] wherein, x(t) is the system state variable x(t) = [x 1 (t), x 2 (t), x 3 (t), x 4 (t)] T ; x d (t) is the set value.

[0106] After defining the system consistency error for steam pressure control of the OTSG, the terminal device further sums the integral of the system consistency error and the system state variables corresponding to the state space model of the OTSG, thereby designing the sliding mode surface for steam pressure control of the OTSG based on the integral terminal sliding mode controller.

[0107] Exemplarily, the terminal device sums the integral of the system consistency error and the system state variables to obtain the sliding mode surface s(t) as follows:

[0108]

[0109] Among them, e(t) is the system consistency error; is the integral of the system state variable x(t); f > 0, and 0 < λ < 1.

[0110] Step S302: Perform sliding mode control on the steam pressure of the once-through steam generator through the integral terminal sliding mode controller.

[0111] After the terminal device designs the sliding mode surface and designs the integral terminal sliding mode controller based on the interference observer in combination with the sliding mode control algorithm based on this system state space model, the external disturbance estimation data, and the sliding mode surface, it can perform sliding mode control on the steam pressure of the OTSG through the integral terminal sliding mode controller according to the sliding mode surface. Thus, during the operation of the OTSG, the steam pressure of the OTSG can be quickly stabilized near the set value, and the phenomenon of chattering of the steam pressure of the OTSG caused by external disturbances can be avoided.

[0112] Please refer to Figure 4 , Figure 4 is Figure 3 the schematic diagram of the refined step flow of step S302 in

[0113] As Figure 4 shown, in some embodiments, the above-mentioned step S302: Perform sliding mode control on the steam pressure of the once-through steam generator through the integral terminal sliding mode controller may include the following steps S401 and S402.

[0114] Step S401: Output control parameters based on the system state variables of the once-through steam generator through the integral terminal sliding mode controller.

[0115] When the terminal device performs sliding mode control on the steam pressure of the OTSG according to the sliding mode surface based on the integral terminal sliding mode controller, it first outputs control parameters based on the system state variables of the OTSG through the integral terminal sliding mode controller. Among them, the control parameters output by the integral terminal sliding mode controller are used to drive the system state of the OTSG to the sliding mode surface and move along the sliding mode surface to the desired equilibrium point.

[0116] Step S402: Drive the once-through steam generator through the actuator of the once-through steam generator according to the control parameters.

[0117] After the terminal device outputs the control parameters through the integral terminal sliding mode controller, it further drives the OTSG to operate according to the control parameters through the actuator of the OTSG, so as to drive the steam pressure state of the OTSG to the sliding mode surface and make the steam pressure state of the OTSG move along the sliding mode surface until the steam pressure state of the OTSG reaches the desired equilibrium point.

[0118] Exemplarily, asFigure 5 The system architecture for steam pressure control of the OTSG shown in the figure. The terminal device acquires the OTSG system state variables through the sensors of the OTSG, and then constructs the state space model of the above OTSG based on the system state variables. Moreover, the terminal device also defines the system consistency error for steam pressure control of the OTSG, and sums the system consistency error with the integral of the OTSG system state variables to design a sliding mode surface. Then, the terminal device introduces a pre-designed disturbance observer to online estimate the outlet steam flow disturbance (external disturbance) received by the OTSG, so as to obtain the external disturbance estimation data of the OTSG, and transmits the external disturbance estimation data to the pre-designed integral terminal sliding mode controller based on the disturbance observer. Finally, the terminal device outputs, based on the integral terminal sliding mode controller and the system state variables of the OTSG, control parameters for driving the system state (steam pressure state) of the OTSG to the sliding mode surface and moving along the sliding mode surface to the desired equilibrium point to the actuator of the OTSG. Thus, the actuator drives the OTSG to operate according to the control parameters to quickly drive the steam pressure state of the OTSG to the sliding mode surface and move along the sliding mode surface to the desired equilibrium point.

[0119] In some embodiments, the DC steam generator pressure control method provided by the embodiments of the present application may further include the following steps:

[0120] Based on the system state variables of the DC steam generator and the external disturbance estimation data, determine an integral terminal sliding mode controller based on a disturbance observer, where the disturbance observer is a disturbance observer that online estimates the external disturbance of the DC steam generator to obtain the external disturbance estimation data;

[0121] Perform sliding mode control on the steam pressure of the DC steam generator through the integral terminal sliding mode controller.

[0122] The terminal device may also pre-combine the external disturbance estimation data of the OTSG and the sliding mode control algorithm to design an integral terminal sliding mode controller based on a disturbance observer. That is, during the operation of the OTSG, the terminal device real-time acquires the system state variables of the OTSG based on the sensors of the OTSG, and then combines the acquired system state variables and the external disturbance estimation data obtained by online estimating the external disturbance of the OTSG using a disturbance observer with the sliding mode control algorithm, so as to design an integral terminal sliding mode controller based on a disturbance observer.

[0123] Exemplarily, the terminal device combines the external disturbance estimation data and the sliding mode control algorithm to design an integral terminal sliding mode controller u(t) based on a disturbance observer as follows:

[0124]

[0125] Among them, sgn(·) is the sign function; the gain k represents the coupling strength, and k > 0; s(t) is the sliding mode surface; x(t) is the system state variable x(t) = [x 1 (t), x 2 (t), x 3 (t), x 4 (t)] T ; is the estimated value of the disturbance quantity d(t) of the outlet steam flow rate received by the OTSG (i.e., the estimated data of external disturbance); is the first derivative of the set value x d (t); f > 0, and 0 < λ < 1; A(t), B -1 (t), C(t) are system matrices.

[0126] After that, the terminal device can perform sliding mode control on the steam pressure of the OTSG through the integral terminal sliding mode controller according to the pre-designed sliding mode surface, so as to quickly stabilize the steam pressure of the OTSG near the set value during the operation of the OTSG and avoid the phenomenon of chattering of the steam pressure of the OTSG caused by external disturbances.

[0127] In this embodiment, the terminal device can first construct the system state space model of the OTSG according to the obtained system state variables of the OTSG and define the consistency error of the system state variables; then, the terminal device introduces a disturbance observer to estimate the disturbance of the outlet steam flow rate received by the OTSG, and combines the robust sliding mode control algorithm to design an integral terminal sliding mode controller based on the disturbance observer to control the steam pressure of the OTSG. In this way, the steam pressure of the OTSG can be efficiently and reliably controlled, so as to quickly stabilize the steam pressure of the OTSG near the set value during the operation of the OTSG and avoid the phenomenon of chattering of the steam pressure of the OTSG caused by external disturbances received by the OTSG.

[0128] Please refer to Figure 6 , Figure 6 which is the schematic diagram of the simulation results involved in the steam control method provided by the embodiment of the present application in some embodiments.

[0129] As Figure 6As shown, in some embodiments, by simulating the process of controlling the steam pressure of the OTSG by the terminal device based on the above integral terminal sliding mode controller, it can be seen that the steam pressure response curve of the OTSG (characterizing the steam pressure state of the OTSG under the control of the integral terminal sliding mode controller) is driven to the sliding surface within a certain time and always moves along the sliding surface close to the desired equilibrium point (set value) without generating chattering. Thus, it can be shown that the DC steam generator pressure control method provided by the embodiments of the present application can efficiently and reliably control the steam pressure of the OTSG.

[0130] Based on the same inventive concept, the embodiments of the present application also provide a DC steam generator pressure control device for implementing the above-mentioned DC steam generator pressure control method. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the DC steam generator pressure control device provided below can refer to the limitations on the DC steam generator pressure control method in the above text and will not be repeated here.

[0131] In one embodiment, as Figure 7 shown, a DC steam generator pressure control device is provided, including: an acquisition module 701, a disturbance estimation module 702, and a control module 703, where:

[0132] The acquisition module 701 is used to acquire the system state space model of the DC steam generator of the nuclear power plant;

[0133] The disturbance estimation module 702 is used to perform online estimation on the external disturbance of the DC steam generator to obtain the external disturbance estimation data of the DC steam generator;

[0134] The control module 703 is used to perform sliding mode control on the steam pressure of the DC steam generator based on the system state space model and the external disturbance estimation data.

[0135] In some embodiments, the external disturbance of the DC steam generator includes: the outlet steam flow disturbance received by the DC steam generator. The control module 703 is further used to perform online estimation on the outlet steam flow disturbance received by the DC steam generator based on a preset disturbance observer to obtain the external disturbance estimation data of the DC steam generator.

[0136] In some embodiments, the DC steam generator pressure control device further includes:

[0137] The disturbance design module is used to obtain the system state variables of the once-through steam generator, and obtain the disturbance quantity of the outlet steam flow of the once-through steam generator; and design the disturbance observer based on the system state variables, the disturbance quantity of the outlet steam flow, and the influence of the sliding mode control on the steam pressure of the once-through steam generator on the disturbance observation.

[0138] In some embodiments, the control module 703 is further configured to determine an integral terminal sliding mode controller based on the system state space model, the external disturbance estimation data, and a preset sliding mode surface; and perform sliding mode control on the steam pressure of the once-through steam generator through the integral terminal sliding mode controller.

[0139] In some embodiments, the control module 703 is further configured to determine the system consistency error based on the system state variables of the once-through steam generator; and perform a summation calculation on the integral of the system consistency error and the system state variables of the once-through steam generator to obtain the sliding mode surface when controlling the steam pressure of the once-through steam generator.

[0140] In some embodiments, the control module 703 is further configured to output control parameters based on the system state variables of the once-through steam generator through the integral terminal sliding mode controller; and drive the once-through steam generator according to the control parameters through the actuator of the once-through steam generator.

[0141] In some embodiments, the control module 703 is further configured to determine an integral terminal sliding mode controller based on the disturbance observer based on the system state variables of the once-through steam generator and the external disturbance estimation data, where the disturbance observer is a disturbance observer that performs online estimation on the external disturbance of the once-through steam generator to obtain the external disturbance estimation data; and perform sliding mode control on the steam pressure of the once-through steam generator through the integral terminal sliding mode controller.

[0142] In some embodiments, the acquisition module 701 is further configured to construct a system state space model of the once-through steam generator based on the system state variables of the once-through steam generator of the nuclear power plant.

[0143] In some embodiments, the system state variables of the once-through steam generator include: the input system state variables of the once-through steam generator and the output system state variables of the once-through steam generator; where the input system state variables include: the primary side inlet temperature, the secondary side inlet feed water temperature, the secondary side inlet feed water flow rate, and the secondary side outlet steam flow rate, and the output system state variables include: the primary side outlet temperature, the secondary side outlet steam temperature, and the secondary side steam pressure.

[0144] Each module in the DC steam generator pressure control device provided by the embodiments of the present application can be implemented in whole or in part by software, hardware, or a combination thereof. The above-mentioned modules can be embedded in the processor of the computer device in hardware form or be independent of it, or be stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

[0145] In some embodiments, the present application provides a computer device, which can be a server, and its internal structure diagram can be as Figure 8 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store model parameters related to the liquid metal reactor. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a DC steam generator pressure control method.

[0146] Those skilled in the art can understand that Figure 8 the structure shown in

[0147] is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different component layout.

[0147] In some embodiments, a computer device is provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the following steps are implemented:

[0148] Obtain the system state space model of the DC steam generator of the nuclear power plant;

[0149] Perform online estimation on the external disturbance of the DC steam generator to obtain the external disturbance estimation data of the DC steam generator;

[0150] Perform sliding mode control on the steam pressure of the DC steam generator based on the system state space model and the external disturbance estimation data.

[0151] In some of these embodiments, the external disturbances of the once-through steam generator include: the disturbance of the outlet steam flow rate received by the once-through steam generator;

[0152] The online estimation of the external disturbances of the once-through steam generator to obtain the estimated data of the external disturbances of the once-through steam generator includes:

[0153] Based on a preset disturbance observer, the online estimation of the disturbance of the outlet steam flow rate received by the once-through steam generator is performed to obtain the estimated data of the external disturbances of the once-through steam generator.

[0154] In some of these embodiments, the method further includes:

[0155] Obtaining the system state variables of the once-through steam generator, and obtaining the disturbance amount of the outlet steam flow rate of the once-through steam generator;

[0156] Based on the system state variables, the disturbance amount of the outlet steam flow rate, and the influence of the sliding mode control on the steam pressure of the once-through steam generator on the disturbance observation, the disturbance observer is designed.

[0157] In some of these embodiments, the sliding mode control of the steam pressure of the once-through steam generator based on the system state space model and the estimated data of the external disturbances includes:

[0158] Based on the system state space model, the estimated data of the external disturbances, and a preset sliding mode surface, an integral terminal sliding mode controller is determined;

[0159] The sliding mode control of the steam pressure of the once-through steam generator is performed through the integral terminal sliding mode controller.

[0160] In some of these embodiments, when the processor executes the computer program, the following steps are further implemented:

[0161] Based on the system state variables of the once-through steam generator, the system consistency error is determined;

[0162] The sum of the integral of the system consistency error and the system state variables of the once-through steam generator is calculated to obtain the sliding mode surface when the sliding mode control of the steam pressure of the once-through steam generator is performed.

[0163] In some of these embodiments, the sliding mode control of the steam pressure of the once-through steam generator through the integral terminal sliding mode controller includes:

[0164] The integral terminal sliding mode controller outputs control parameters based on the system state variables of the once-through steam generator;

[0165] Drive the once-through steam generator by an actuator of the once-through steam generator according to the control parameters.

[0166] In some embodiments, the method further includes:

[0167] Determine an integral terminal sliding mode controller based on a disturbance observer according to system state variables of the once-through steam generator of a nuclear power plant and the external disturbance estimation data, where the disturbance observer is a disturbance observer for online estimating an external disturbance of the once-through steam generator to obtain the external disturbance estimation data;

[0168] Perform sliding mode control on the steam pressure of the once-through steam generator by the integral terminal sliding mode controller.

[0169] In some embodiments, the obtaining of the system state space model of the once-through steam generator of a nuclear power plant includes:

[0170] Construct the system state space model of the once-through steam generator based on system state variables of the once-through steam generator of a nuclear power plant.

[0171] In some embodiments, the system state variables include: input system state variables of the once-through steam generator, and output system state variables of the once-through steam generator; where the input system state variables include: primary side inlet temperature, secondary side inlet feed water temperature, secondary side inlet feed water flow rate, and secondary side outlet steam flow rate, and the output system state variables include: primary side outlet temperature, secondary side outlet steam temperature, and secondary side steam pressure.

[0172] In some embodiments, a computer-readable storage medium is provided, on which a computer program is stored. The steps implemented when the computer program is executed by a processor are the same as those implemented when the processor in the above computer device executes the computer program, and details thereof will not be described herein again.

[0173] In one embodiment, a computer program product is provided, including a computer program. The steps implemented when the computer program is executed by a processor are the same as those implemented when the processor in the above computer device executes the computer program, and details thereof will not be described herein again.

[0174] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0175] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0176] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A pressure control method for a once-through steam generator, characterized in that: The method comprises: Obtaining the system state space model of the once-through steam generator of a nuclear power plant; Performing online estimation of external disturbance of the once-through steam generator to obtain external disturbance estimation data of the once-through steam generator; The steam pressure of the once-through steam generator is subjected to sliding mode control based on the system state space model and the external disturbance estimation data.

2. The method according to claim 1, characterized in that The external disturbance of the once-through steam generator includes: the outlet steam flow disturbance of the once-through steam generator; The online estimation of the external disturbance of the once-through steam generator to obtain external disturbance estimation data of the once-through steam generator includes: Based on a preset disturbance observer, an online estimation is performed on the outlet steam flow disturbance suffered by the once-through steam generator to obtain external disturbance estimation data of the once-through steam generator.

3. The method according to claim 2, characterized in that The method further comprises: Acquire a system state variable of the once-through steam generator, and acquire a disturbance value of an outlet steam flow rate of the once-through steam generator; The disturbance observer is designed based on the system state variables, the disturbance amount of the outlet steam flow rate, and the influence of sliding mode control on the steam pressure of the once-through steam generator on disturbance observation.

4. The method according to claim 1, characterized in that The performing sliding mode control on the steam pressure of the once-through steam generator based on the system state space model and the external disturbance estimation data comprises: Determining an integral terminal sliding mode controller based on the system state space model, the external disturbance estimation data and a preset sliding mode surface; The steam pressure of the once-through steam generator is subjected to sliding mode control by means of the integral terminal sliding mode controller.

5. The method according to claim 4, characterized in that The method further comprises: determining a system consistency error based on a system state variable of the once-through steam generator; The system consistency error and the integral of the system state variable of the once-through steam generator are summed up and calculated to obtain a sliding surface when the steam pressure of the once-through steam generator is controlled.

6. The method according to claim 4, characterized in that The step of performing sliding mode control on the steam pressure of the once-through steam generator by using the integral terminal sliding mode controller comprises: Outputting a control parameter based on a system state variable of the once-through steam generator through the integral terminal sliding mode controller; The once-through steam generator is driven according to the control parameters by an actuator of the once-through steam generator.

7. The method according to claim 1, characterized in that The method further comprises: Based on the system state variables of the direct current steam generator and the external disturbance estimation data, determining an integral terminal sliding mode controller based on a disturbance observer, wherein the disturbance observer is a disturbance observer that performs online estimation of the external disturbance of the direct current steam generator to obtain the external disturbance estimation data; The steam pressure of the once-through steam generator is subjected to sliding mode control by means of the integral terminal sliding mode controller.

8. The method according to claim 1, characterized in that The method of obtaining a system state space model of a once-through steam generator of a nuclear power plant comprises: A system state space model of the once-through steam generator of a nuclear power plant is constructed based on the system state variables of the once-through steam generator.

9. The method according to any one of claims 1 to 8, characterized in that The system state variables of the direct current steam generator include: the input system state variables of the direct current steam generator, and, the output system state variables of the direct current steam generator; wherein, the input system state variables include: the primary side inlet temperature, the secondary side inlet feed water temperature, the secondary side inlet feed water flow rate and the secondary side outlet steam flow rate, and the output system state variables include: the primary side outlet temperature, the secondary side outlet steam temperature and the secondary side steam pressure.

10. A pressure control device for a direct current steam generator, characterized in that: The device comprises: An acquisition module, used for acquiring a system state space model of a once-through steam generator of a nuclear power plant; An interference estimation module, used for online estimation of external disturbance of the direct current steam generator to obtain external interference estimation data of the direct current steam generator; A control module is used to perform sliding mode control on the steam pressure of the direct current steam generator based on the system state space model and the external disturbance estimation data.

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