Vapor generator liquid level control system verification platform based on hardware-in-the-loop simulation

Abstract

The invention discloses a steam generator liquid level control system verification platform based on hardware-in-the-loop simulation, and belongs to the technical field of nuclear reactor control. The invention aims to solve the problem of inaccurate description of physical equipment characteristics in the existing simulation technology. The platform comprises a DCS control system, a controlled device, an industrial control computer and a data communication network. The DCS control system comprises an upper computer, a Siemens S7-400 controller and a Siemens ET200M distributed I / O system, the controlled device is a Speedgoat real-time simulation platform carrying a steam generator simulation model, and the data communication network is composed of an industrial Ethernet and a PROFIBUS field bus. The platform supports a rapid control prototype and hardware-in-the-loop simulation dual mode, is compatible with PID and an intelligent control algorithm, has the functions of data storage, visual monitoring and the like, can accurately simulate actual working conditions, realizes full-process coverage from design to verification, improves simulation credibility and research and development efficiency, and provides a reliable test environment for steam generator liquid level control research.

Description

Technical Field

[0001] This invention belongs to the field of nuclear reactor control technology, specifically relating to a verification platform for a steam generator liquid level control system based on hardware-in-the-loop simulation. Background Technology

[0002] The steam generator is a crucial component of a pressurized water reactor (PWR), playing a vital role in energy exchange between the primary and secondary loops. Currently, large PWR nuclear power plants commonly employ U-type steam generators (UTSGs). The main function of the steam generator is to transfer heat generated by the reactor core in the primary loop to the secondary loop, producing steam to power the turbine. Steam generator level control directly impacts the operational safety of the nuclear power plant. Although simulation technology provides an effective tool for related research, its accuracy and reliability still face challenges, primarily due to the high complexity of model construction and the difficulty in accurately simulating the dynamic characteristics of physical equipment. Furthermore, simulation technology struggles to fully and accurately describe the dynamic, static, and time delay characteristics of physical equipment, all of which significantly affect the confidence and accuracy of the simulation system.

[0003] Therefore, although simulation technology has made some progress in nuclear reactor research, how to further improve the accuracy and reliability of simulation remains an urgent problem to be solved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a verification platform for a steam generator level control system based on hardware-in-the-loop simulation, which addresses the shortcomings of the prior art and solves the technical problem that the existing simulation technology does not accurately describe the dynamic characteristics, static characteristics and time delay of the physical equipment, thereby affecting the accuracy of the simulation.

[0005] The present invention adopts the following technical solution: A verification platform for a steam generator level control system based on hardware-in-the-loop simulation, including a DCS control system, controlled equipment, industrial control computer, and data communication network. The DCS control system includes a host computer, a controller, and a distributed I / O system. The host computer and the controller are connected through a data communication network and are used to monitor and manage the entire system and control process and store historical operating data. The controller is connected to the distributed I / O system through a data communication network. The distributed I / O system acts as a bridge for instruction transmission between the controller and external devices, enabling signal reception and transmission. The controlled equipment is equipped with a steam generator simulation model and a valve opening calculation program. It establishes a signal transmission link with the distributed I / O system through a data communication network, receives control signals and feeds back operating status signals. The industrial control computer and controller establish a signal connection through a distributed I / O system to realize intelligent control algorithm calculations, and connect to the controlled equipment through a data communication network to realize model loading, modification and operation status monitoring.

[0006] Preferably, the controller is a Siemens S7-400 controller, including a CPU module, a power supply module, and a communication module.

[0007] Preferably, the distributed I / O system is built using Siemens ET200M and includes a power supply module, a digital input / output module, and an analog input / output module; the analog input / output module is a current analog module; the analog input module supports 8 channels of analog input signals; and the analog output module supports 8 channels of analog output signals.

[0008] Preferably, the controlled device is the Speedgoat real-time simulation platform, which includes a real-time target machine, I / O boards, I / O cables and matching wiring ports, and is configured with a Simulink driver library and test model; The real-time target machine is seamlessly integrated with the MATLAB / Simulink model; the steam generator simulation model and valve opening calculation program are both built on MATLAB / Simulink 2021b and deployed within the Speedgoat real-time target machine; the Speedgoat real-time simulation platform is designed for hardware-in-the-loop simulation and industrial automation applications.

[0009] Preferably, the data communication network includes an industrial Ethernet and a PROFIBUS fieldbus; the host computer and the controller are connected via an industrial Ethernet; the controller and the distributed I / O system are connected via a PROFIBUS fieldbus, and the distributed I / O system is connected to the PROFIBUS network via a twisted-pair cable and the controller's communication module; the industrial control computer and the controlled equipment are connected via an industrial Ethernet, and are used only for model deployment, adjustment, and data monitoring; the distributed I / O system and the industrial control computer use serial communication to receive and send analog signals.

[0010] Preferably, the analog input module of the distributed I / O system receives three input signals: a liquid level setpoint, a liquid level measurement, and a steam-water mismatch value; the analog output module of the distributed I / O system sends one output signal, which is the water flow demand value; the industrial control computer receives the liquid level setpoint, the liquid level measurement, and the steam-water mismatch value through the analog output module; and the industrial control computer sends the water flow demand value through the analog input module.

[0011] Preferably, the DCS control system directly implements PID control of the steam generator liquid level through the controller, and the control program is designed using ladder logic programming language. The control program includes an input conversion module, a PID calculation module, an output conversion module, and a register group. The input conversion module converts a 4~20mA analog current signal into an actual liquid level value of 0~1. The output conversion module converts the control quantity output by the PID calculation module into a 4~20mA analog current signal. The register group includes a bit register and a word register. The bit register is used to process switch logic signals, and the word register is used to process integer data and arithmetic operations.

[0012] Preferably, the platform supports a rapid control prototype mode, in which the control algorithm is deployed in the controller or industrial control computer, the controller hardware model is run, and the controlled object is a steam generator simulation model; after the controller completes the design and simulation verification, the control program can be compiled and downloaded to the controller for closed-loop verification of the entire control system; when it is necessary to adjust the control parameters or model, the next closed-loop verification can be performed directly after modification by the host computer or industrial control computer.

[0013] Preferably, the platform supports a hardware-in-the-loop simulation mode, in which the controller and distributed I / O system in the closed-loop control loop are hardware devices and the controlled object is a steam generator simulation model, or the controller, distributed I / O system and some actuators are hardware devices and the rest are virtual devices; the hardware-in-the-loop simulation mode adopts modular programming and standard interface design.

[0014] Preferably, the industrial control computer supports complex intelligent control algorithms, which can replace traditional PID control algorithms; the platform is configured with a database to store system operation data filtered by the user, and the database supports data export; the host computer provides a visual human-machine interface, allowing users to monitor the status of each interface in real time, customize data curve displays, observe the mechanism's action process, and access the reactor operation monitoring screen.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: A hardware-in-the-loop simulation-based verification platform for a steam generator level control system integrates a DCS control system, controlled equipment, an industrial control computer, and a data communication network to construct a complete signal transmission and control link. The host computer handles monitoring and data storage, a distributed I / O system ensures signal transmission, the industrial control computer provides intelligent algorithm computing power, and the controlled equipment carries the core simulation model, forming a closed-loop control system. This fundamentally solves the problem of the disconnect between virtual and real simulation technologies. It retains the safety and reliability of the DCS control system while overcoming the computing power limitations of traditional controllers through the industrial control computer. It supports integrated simulation and testing, laying the foundation for future functional expansion and ensuring the platform can adapt to the complex requirements of steam generator level control, achieving full-process coverage from model deployment to control verification.

[0016] Furthermore, the Siemens S7-400 series controllers are mature in industrial applications, featuring stability, durability, strong communication capabilities, and ease of expansion and maintenance, making them suitable for the stringent reliability requirements of nuclear power plant control. The dual-memory design of the 414-H series CPU meets the routine computational needs of steam generator level control, ensuring independent storage and stable operation of programs and data. The specialized design of the CP443-1 and CP443-5 dual communication modules enables targeted communication with the host computer and distributed I / O system, respectively, avoiding signal transmission conflicts and improving communication efficiency and stability. Precise selection matches the platform's control requirements, providing core hardware support for the stable operation of the entire system and ensuring accurate execution of control commands and real-time data interaction.

[0017] Furthermore, the analog module adopts an analog current signal type, conforming to the common signal standards in the industrial control field, ensuring the anti-interference and stability of signal transmission. The design of 8 input / output channels can meet the transmission requirements of key signals such as liquid level setpoints and liquid level measurements required for three-impulse control, while reserving expansion space. Through a standardized I / O architecture, a reliable connection bridge is built between the controller and external devices, ensuring the accurate transmission of control commands and operating status signals, providing key hardware support for the realization of closed-loop control. At the same time, compatibility with Siemens equipment ensures the system's maintainability and scalability.

[0018] Furthermore, Speedgoat is designed specifically for Simulink Real-Time, enabling seamless, one-click deployment from Simulink models to real-time running code. This significantly reduces the difficulty and technical barriers to converting complex steam generator models (such as UTSG models) and valve opening calculation programs into real-time execution. Its hardware's high real-time performance and low latency ensure that simulation models can run at speeds matching real physical processes, which is crucial for achieving high-confidence hardware-in-the-loop simulations. This feature allows the platform to fully leverage the powerful modeling and algorithm development ecosystem of MATLAB / Simulink.

[0019] Furthermore, the host computer and controller use industrial Ethernet, the controller and I / O use PROFIBUS, I / O and the industrial computer use serial ports, and the industrial computer and the controlled devices use (non-control) Ethernet, adopting a hierarchical and heterogeneous communication architecture. Industrial Ethernet ensures the real-time performance and high bandwidth of monitoring data; the PROFIBUS fieldbus is specifically designed for industrial control, offering strong real-time performance and high reliability, perfectly adapting to high-speed, deterministic data exchange between the controller and distributed I / O; the Ethernet between the industrial computer and the controlled devices is dedicated to model management rather than control loops, isolating management data streams from control data streams and avoiding network congestion interference with real-time control. This architecture design ensures performance while also conforming to typical design specifications of industrial control systems, improving the platform's realism and reliability.

[0020] Furthermore, the types and quantities of analog input and output signals correspond to the three-impulse control strategy for steam generator level control, transforming the abstract control requirements (three-impulse control) into specific hardware I / O configurations. The explicit requirement for three inputs (setpoint, measured value, and mismatch value) and one output (flow demand value) provides precise guidance for control program writing and I / O channel allocation. This feature reflects the platform's targeted and comprehensive design, ensuring the complete simulation and testing of classic steam generator level control schemes and verifying their performance in a semi-physical environment.

[0021] Furthermore, ladder diagrams are a universal language for PLC programming, easy for engineers to understand and debug, and conform to industrial practices. A dedicated input / output conversion module is designed to handle the mapping between 4-20mA signals and internally calculated values ​​(0-1), serving as a necessary bridge between physical signals and digital algorithms, ensuring control accuracy. Bit registers and word registers are used to handle logical states and numerical data respectively, resulting in a clear program structure, separation of logic and operation, and enhanced program reliability and maintainability. This feature guarantees that the control logic can operate efficiently and stably on real S7-400 hardware.

[0022] Furthermore, the control algorithm is directly deployed on the controller or industrial control computer, with the controlled object being a simulation model. This eliminates the need to build a complete physical system, reducing upfront R&D costs and risks. Closed-loop verification can be achieved immediately after the control program is compiled and downloaded. If problems arise, parameters can be adjusted directly via a host computer or industrial control computer without complex hardware modifications, improving R&D iteration efficiency. This provides an efficient method for the initial verification of control algorithms, enabling rapid screening of feasible control schemes, reducing the workload of subsequent hardware-in-the-loop testing, and achieving a rapid transition from algorithm design to initial verification, significantly improving the overall R&D progress.

[0023] Furthermore, the simulation's realism and engineering applicability are enhanced. By integrating actual hardware devices (controllers, distributed I / O systems, etc.) into the closed-loop control circuit, while using virtual devices for the remaining parts, the dynamic characteristics and signal interaction processes of the physical devices can be accurately replicated, solving the problem of the disconnect between pure virtual simulation and actual operating conditions. Modular programming and standard interface design make the combination and configuration of virtual and physical modules more flexible, allowing for targeted integration of hardware devices according to testing needs to conduct specialized tests. This approach retains the flexibility and low-cost advantages of simulation technology while enhancing the reliability of simulation results through hardware integration, providing reliable verification for the engineering application of control schemes and ensuring that the technical solutions can be directly adapted to actual industrial scenarios.

[0024] Furthermore, the industrial control computer supports complex intelligent control algorithms to replace traditional PID algorithms, providing a platform for the verification of new control methods and helping to improve the intelligence level of steam generator level control. The database function enables the filtering, storage, and export of system operation data, facilitating user traceability of the operation process and providing a data foundation for in-depth data analysis and control algorithm optimization. The visual human-machine interface allows users to monitor interface status in real time, customize data curves, and observe mechanism actions, intuitively grasping system dynamics and reducing operational difficulty and monitoring costs. This ensures the platform not only meets basic simulation and testing needs but also possesses functional scalability and data mining capabilities, enhancing its overall practicality and applicability.

[0025] In summary, this invention achieves a dual improvement in simulation accuracy and engineering applicability through precise hardware selection, clear signal link design, and dual simulation mode support. The modular design ensures flexible configuration, is compatible with traditional and intelligent control algorithms, covers the entire R&D process, significantly reduces R&D costs and shortens the cycle, and provides efficient and reliable technical support for steam generator level control research.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the DCS control system architecture of the present invention; Figure 2 This is a schematic diagram of the hardware-in-the-loop simulation platform for the DCS control system of the present invention. Figure 3 This is a physical hardware diagram of the hardware-in-the-loop simulation platform for the DCS control system of this invention. Figure 4 This is a schematic diagram of the UTSG model of the present invention; Figure 5 This is the valve opening calculation program of the present invention; Figure 6 This is a schematic diagram of the hardware configuration structure of the present invention; Figure 7 This is a schematic diagram of the hardware configuration in the STEP 7 software of this invention; Figure 8 This is a schematic diagram of the three-impulse control program structure of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0030] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0031] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0032] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0033] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0034] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0035] This invention provides a verification platform for a steam generator level control system based on hardware-in-the-loop simulation. Integrating simulation and testing functions, it effectively solves the problem of inaccurate description of physical equipment characteristics in existing simulation technologies. The platform supports both fully virtual simulation and hardware-in-the-loop testing modes. Its modular architecture allows for flexible configuration of virtual and physical modules, accurately simulating actual nuclear reactor operating conditions and providing high-confidence data support. It is compatible with traditional PID and intelligent control algorithms, and features data storage and export, visualization monitoring, and other functions, covering the entire process from scheme design to functional verification. This significantly improves R&D efficiency, enhances simulation credibility and engineering applicability, and provides a reliable comprehensive testing environment for steam generator level control research.

[0036] Please see Figure 1 The present invention provides a verification platform for a steam generator level control system based on hardware-in-the-loop simulation, comprising a DCS control system, controlled equipment, an industrial control computer, and a data communication network.

[0037] The DCS control system is used to realize the closed-loop control logic of the liquid level of the steam generator. The DCS control system includes a host computer and a controller and I / O module connected through a communication network. The host computer and the controller realize real-time data interaction through the data communication network, which is used to monitor and manage the entire system and control process and store historical operation data. The controller is connected to the distributed I / O system through a data communication network. The distributed I / O system acts as a bridge for instruction transmission between the controller and external devices, enabling signal reception and transmission. The controlled equipment is equipped with a steam generator simulation model and a valve opening calculation program. It establishes a signal transmission link with the distributed I / O system through a data communication network, receives control signals and feeds back operating status signals. The industrial control computer and controller establish a signal connection through a distributed I / O system to realize intelligent control algorithm calculations, and connect to the controlled equipment through a data communication network to realize model loading, modification and operation status monitoring.

[0038] DCS control systems, due to their design principles, can effectively reduce system risks and improve control stability and effectiveness, and are widely used in industrial production. Meanwhile, DCS control systems, due to their safety, reliability, and economy, are widely used in nuclear power control.

[0039] The architecture of a DCS control system mainly includes field control stations, monitoring and operation stations, and network communication components. The primary task in designing a hardware-in-the-loop (HIL) simulation platform for a DCS control system is hardware selection and network connectivity. Siemens, a leading company in the electrical field, produces industrial control equipment widely used in industrial production. The Siemens S400 series, also known as the S7-400, is a powerful programmable logic controller (PLC). This controller is characterized by its stability, durability, strong communication capabilities, and ease of expansion and maintenance. Therefore, the Siemens S7-400 was selected as the core controller for the design and development of the corresponding DCS control system.

[0040] While the S7-400 controller possesses strong conventional computing capabilities, it has limitations when facing the high computing power demands of intelligent algorithms. Therefore, an external industrial control computer is connected to the platform as an intelligent computing unit, supporting flexible switching between traditional PID control and intelligent algorithms.

[0041] Please see Figure 2This diagram shows the semi-physical simulation control system structure of a DCS control system, which will be used for subsequent research on steam generator level control. The dotted line in the diagram represents the constructed DCS control system. The host computer simultaneously functions as an engineer's station and an operator's station, enabling monitoring and management of the entire system and control process. It also includes a memory to retain historical data from the control system's operation. Intelligent control is implemented through an industrial control computer. Normally, this DCS control system directly controls the equipment via an S7-400. When intelligent control is required, the S7-400 sends control signals through its I / O modules to achieve control via the industrial computer. The industrial computer is connected to the controlled object via Ethernet. However, the industrial computer does not send control signals via Ethernet; it only loads, modifies, and monitors the controlled equipment model via Ethernet. The physical prototype is shown below. Figure 3 As shown.

[0042] The specific hardware used is as follows: 1. Controller The Siemens S7-400 controller is the core component of this DCS control system, comprising a CPU module, a power supply module, and a communication module. The CPU module is a Siemens 414-H series model, with 2MB of dedicated memory for programs and 2MB for data, sufficient for standard control requirements. The communication section includes two communication processing modules, CP443-1 and CP443-5. CP443-1 handles communication with the host computer, while CP443-5 handles communication with the I / O modules.

[0043] The external advanced control equipment uses an industrial control computer with high computing power to meet the requirements of advanced control algorithms. 2.I / O module The I / O module serves as a bridge for command transmission between the controller and actuators. A Siemens ET200M is selected to build a distributed I / O system. This system's hardware components include a power supply module, digital input / output (DI, DO) modules, and analog input / output (AI, AO) modules. Analog modules will be primarily used for control. Currently, the AI ​​and AO modules in this device are both current analog modules, receiving currents ranging from 4 to 20 mA. The AI ​​supports 8 analog input signals (address range: PIW512~PIW527), and the AO supports 8 analog output signals (address range: PQW528~PQW543).

[0044] 3. Controlled equipment The controlled device is the Speedgoat real-time simulation platform, a real-time simulation and testing system developed by the Swiss company Speedgoat, primarily designed for hardware-in-the-loop simulation and industrial automation applications. The Speedgoat hardware system includes a real-time target machine, I / O boards, I / O cables, and associated wiring ports, while the software includes a Simulink driver library and test models. The Speedgoat real-time target machine used in this paper employs an Intel Celeron 2.0 GHz quad-core CPU. Due to the company's deep collaboration with MathWorks, its hardware platform is specifically designed and optimized for Simulink Real-Time, enabling seamless integration with MATLAB / Simulink models, significantly reducing model deployment difficulty, and featuring low latency and high reliability. Since the steam generator model in this study is a MATLAB / Simulink model, Speedgoat was chosen as the controlled device, and the steam generator model was integrated to conduct hardware-in-the-loop simulation control research.

[0045] 4. Data Communication Data communication is the method of information exchange in a DCS control system. The host computer and the S7-400 controller are connected via Industrial Ethernet to achieve real-time data exchange. Compared to traditional Ethernet, Industrial Ethernet offers higher accuracy, real-time performance, and higher reliability, meeting the stringent requirements of industrial automation for real-time control and data synchronization.

[0046] The S7-400 controller and I / O modules are connected via a PROFIBUS fieldbus. PROFIBUS is an internationally recognized open fieldbus standard designed specifically for industrial automation. It is a network communication protocol for both unit and field levels, characterized by strong real-time performance, high reliability, and flexible topology. Multiple devices can be connected to a PROFIBUS network, and the CPU can easily and efficiently access devices on the network. Simultaneously, distributed I / O modules are connected to the PROFIBUS network via twisted-pair cables to the CP443-5 modules, enabling data transmission between the controller and I / O modules through the PROFIBUS network.

[0047] The industrial control computer communicates with the Speedgoat real-time target via Ethernet. This communication is only responsible for model deployment adjustments and monitoring of relevant data. The industrial control computer and Speedgoat do not transmit control signals via Ethernet.

[0048] The I / O interface communicates with the industrial computer via serial port, and simultaneously receives and sends analog signals through the serial port and the digital-to-analog converter.

[0049] Based on the above hardware-in-the-loop simulation platform, a subsequent hardware-in-the-loop simulation platform for the steam generator will be established, as detailed below: 1. Deployment of UTSG simulation model Conducting hardware-in-the-loop (HIL) simulation control first requires determining the simulation model of the controlled object. This paper uses the UTSG model as the controlled object, which is built in MATLAB / Simulink 2021b. This simulation model is deployed on the Speedgoat real-time target machine for subsequent control research. The UTSG simulation model is as follows: Figure 4 As shown.

[0050] Additionally, the MATLAB / Simulink program for calculating valve opening needs to be deployed in Speedgoat. Figure 5 As shown, after the program obtains the water flow demand value, it calculates the total CV value, then calculates the CV values ​​of FLCV and LLCV respectively, and then calculates the specific opening degree of each valve through the valve opening CV curve to achieve actual control of the liquid level.

[0051] 2. DCS control system hardware configuration Based on the basic structure and control logic of the designed DCS control system, only the S7-400 controller and I / O modules need to be configured in the configuration software. The other devices are externally connected and do not require hardware configuration.

[0052] Please see Figure 6 This document describes the specific structure of the S7-400 controller and I / O modules. In the S7-400 controller system architecture, the CPU module includes one PROFIBUS-DP interface and one MPI / DP interface. CP1 (CP443-1) and CP2 (CP443-5) are the communication modules for the host computer and the slave computer, respectively. The CPU's DP and MPI interfaces, as well as the CP2 module, are all connected to the PROFIBUS network and are also connected to the distributed I / O modules via the PROFIBUS network. CP1 connects to the host computer via Ethernet; the host computer's IP address needs to be configured before communication, and the connection needs to be found in the controller. The I / O modules include interface modules, AI, AO, DI, and DO. Figure 7 This describes the actual configuration of the structure based on 6 in Siemens STEP 7.

[0053] 3. DCS control system I / O interface configuration As can be seen from the three-impulse control structure of the UTSG level control system, the I / O module requires three inputs: level setpoint, level measurement, and steam-water mismatch value, and one output: feedwater flow demand value. These four signals also need to be transmitted to the industrial computer via serial port. Therefore, the I / O usage on the ET200M module is shown in the table below: Table 1 I / O Description Table

[0054] 4. Programming Implementing PID control of UTSG level using a DCS control system only requires an S7-400 controller, eliminating the need for an industrial PC. Therefore, the control program is implemented on the S7-400. The program is designed using Ladder Diagram Programming Language (LAD), which is easy to understand, program, and debug.

[0055] Please see Figure 8 Based on three-impulse control, a three-impulse program for steam generator level control is designed, where the three input signals correspond to... Figure 2-5 The system outputs the difference between the liquid level setpoint, liquid level measurement value, steam flow measurement value, and feedwater flow measurement value. The output signal corresponds to the feedwater flow demand value calculated by the flow controller. After calculating the feedwater flow demand value, the control system calculates the specific valve opening through the valve opening calculation program to control the liquid level.

[0056] from Figure 8 The desired functionality can be divided into two parts: one is the connection between the program and the external environment, and the other is the PID calculation module and data conversion module. Figure 8 The input conversion module and output conversion module are the interface modules between the controller's software program and external I / O. The three inputs correspond to the three analog inputs in Table 1, and the output signal corresponds to one analog output.

[0057] The input module receives analog current signals of 4-20mA and converts them into corresponding actual values ​​for subsequent module calculations. Therefore, data mapping and conversion are required. Since the liquid level variation range in the simulation model built in Speedgoat is between 0 and 1, both input conversion modules 1 and 2 perform the conversion from 4-20mA to (0-1). Similarly, the output conversion module also needs to perform the corresponding liquid level value conversion. To facilitate data storage and monitoring, multiple registers are designed, primarily using two types: bit registers (MD) and word registers (MW). The MD register, as the digital storage unit in the system, is mainly used to process logic signals such as switching signals, including storing and transmitting various switching signals and device status information (such as I / O signals, operating status, alarm indications, etc.). Its read / write operations mainly implement logical judgment and flow control functions in program control. The MW register, as the word storage unit in the system, is mainly used to process various integer data, including analog signals and counter values, supporting basic arithmetic operations (addition, subtraction, multiplication, and division) and data read / write operations.

[0058] The hardware-in-the-loop simulation-based verification platform for a steam generator level control system also has the following extended functions: Intelligent control algorithms: Support the implementation of complex intelligent control algorithms to replace traditional control, and improve the control performance of intelligent control algorithms in actual industrial applications; Database Functionality: Data generated during platform operation can be stored in the corresponding database after being filtered by the user. In addition to supporting the platform's built-in functions, this database also allows users to export data for in-depth data analysis and research. Human-computer interaction interface: Provides a flexible visual operation interface, allowing users to monitor the status of each interface in real time, customize data curve display, observe the action process of specific mechanisms, and call up the operation monitoring screen of the simulated reactor to fully grasp the dynamics of the system.

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0060] To verify the effectiveness of this platform, a hardware-in-the-loop simulation test of the three-impulse PID control strategy for steam generator level was conducted based on the platform. The controlled object (UTSG model and valve model) was deployed in the Speedgoat real-time target machine, and the control algorithm program was downloaded to the Siemens S7-400 controller, forming a complete hardware-in-the-loop closed loop.

[0061] Control performance verification: A series of step disturbance tests were conducted on the platform. For example, a +10% step increase in the secondary loop steam flow was simulated. Experimental data showed that on the hardware-in-the-loop platform, the level control system could adjust and stabilize the level deviation within ±1% of the set value within 25 seconds. In contrast, the same algorithm in pure software offline simulation took approximately 20 seconds to adjust, with the same stabilization accuracy. This approximately 5-second difference mainly reflects the impact of hardware dynamic characteristics such as the real controller scan cycle, I / O module signal conversion, and transmission delay, demonstrating the platform's advantage in capturing the dynamic response of real systems.

[0062] Improved Rapid Prototyping Efficiency: In developing an improved intelligent liquid level control algorithm, the rapid control prototyping mode of this invention platform was utilized. First, the algorithm was designed in MATLAB / Simulink on an industrial control computer, and then co-simulated and verified via Ethernet using a controller model (the controlled object) and a UTSG model in Speedgoat. Algorithm structure adjustments and parameter tuning were all completed within the Simulink environment, reducing the average algorithm iteration verification cycle to less than 30 minutes. In contrast, if each modification required reprogramming and downloading to a physical PLC for testing, a single iteration cycle could take several hours. The platform reduces the estimated algorithm development cycle by 70%.

[0063] Hardware reliability testing: The actual ET200M I / O module underwent a long-term continuous operation test in hardware-in-the-loop simulation mode. The platform ran continuously for 72 hours, simulating various operating conditions, and the input and output signals of the I / O channels were recorded. Data analysis showed that the linearity error of all analog channels was less than 0.2%FS, and no signal interruptions or abnormal fluctuations occurred. This verified the reliability and stability of the selected hardware under simulated continuous operating conditions, a test capability that pure software simulation cannot provide.

[0064] Intelligent Algorithm Comparison Test: Utilizing the platform's flexible architecture, the performance of a traditional PID controller and an intelligent controller based on fuzzy PID (running on an external industrial computer) were compared under the same operating conditions and disturbances. Experimental data shows that when facing water flow disturbances, the intelligent controller's overshoot was reduced by approximately 35% compared to the traditional PID controller, and the recovery time was shortened by approximately 15%. This clearly demonstrates the platform's capability as a verification and performance comparison testing platform for advanced control algorithms.

[0065] The simulation platform of this invention can realize rapid control prototype mode. In rapid control prototype mode, the control algorithm is deployed in the control device, the controller hardware model is run, and the controlled object is the simulation model. After the controller completes the design and simulation verification, it can be immediately compiled and downloaded to the control device to perform closed-loop verification of the entire control system. When a problem occurs, the controller model can be adjusted in the human-computer interaction part and the next closed-loop verification can be performed.

[0066] The simulation platform of this invention can realize hardware-in-the-loop simulation mode. In hardware-in-the-loop simulation mode, if any part of the controller, actuator, process model, sensor and controlled object in closed-loop control is a hardware device, the remaining part is a virtual device, which constitutes the control loop. The hardware-in-the-loop test mode adopts modular programming and standard interface.

[0067] In summary, this invention provides a hardware-in-the-loop simulation-based verification platform for a steam generator level control system. It possesses full virtual simulation capabilities for the control system. The platform supports replacing physical components with virtual modules, facilitating verification testing of control methods or process systems. Simultaneously, it features hardware-in-the-loop testing capabilities, allowing the integration of actual hardware devices into the control loop to achieve highly realistic closed-loop simulations, thereby effectively improving the reliability and engineering applicability of the simulation. This platform can accurately simulate the actual operating conditions of a nuclear reactor, providing researchers with highly reliable data support. Its design integrates simulation and testing functions, supporting not only simulation experiments of the control system but also comprehensive system testing, achieving full-process coverage from scheme design to functional verification, significantly improving R&D efficiency. The platform adopts a modular architecture, with each component independent of the others, facilitating flexible configuration of virtual and physical modules according to specific needs and enabling specialized testing of hardware devices.

[0068] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A hardware-in-the-loop simulation based steam generator level control system verification platform, characterized in that, The DCS control system, controlled equipment, industrial control computer and data communication network are included; The DCS control system includes a host computer, a controller and a distributed I / O system, the host computer is connected with the controller through a data communication network, used for monitoring and managing the whole system and control process and storing operation history data; The controller is connected with the distributed I / O system through the data communication network, the distributed I / O system is used as a command transmission bridge between the controller and external equipment, realizing signal receiving and sending; The controlled equipment is equipped with a steam generator simulation model and a valve opening calculation program, and a signal transmission link is established between the controlled equipment and the distributed I / O system through the data communication network, receiving control signals and feeding back operation state signals; The industrial control computer is connected with the controller through the distributed I / O system, used for realizing intelligent control algorithm operation, and connected with the controlled equipment through the data communication network, realizing model loading, modification and operation state monitoring.

2. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The controller is a Siemens S7-400 controller, including a CPU module, a power module and a communication module.

3. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The distributed I / O system is constructed by using a Siemens ET200M, including a power module, a digital quantity input and output module and an analog quantity input and output module; the analog quantity input and output module is a current analog quantity module; the analog quantity input module supports 8-way analog quantity input signals; the analog quantity output module supports 8-way analog quantity output signals.

4. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The controlled equipment is a Speedgoat real-time simulation platform, including a real-time target machine, an I / O board card, an I / O cable and a matching wiring port, and configured with a Simulink driver library and a test model; The real-time target machine is seamlessly connected with a MATLAB / Simulink model; the steam generator simulation model and the valve opening calculation program are both built in a MATLAB / Simulink 2021b version and deployed in a Speedgoat real-time target machine; the Speedgoat real-time simulation platform is designed for hardware-in-the-loop simulation and industrial automation application.

5. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The data communication network includes an industrial Ethernet and a PROFIBUS field bus; the host computer is connected with the controller through the industrial Ethernet; the controller is connected with the distributed I / O system through the PROFIBUS field bus, the distributed I / O system is connected with the communication module of the controller through a twisted pair and accesses the PROFIBUS network; the industrial control computer is connected with the controlled equipment through the industrial Ethernet, only used for model deployment adjustment and data monitoring; the distributed I / O system and the industrial control computer use serial communication, realizing analog quantity signal receiving and sending.

6. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The analog input module of the distributed I / O system receives three input signals, which are liquid level set value, liquid level measured value and steam-water mismatch value; the analog output module of the distributed I / O system sends one output signal, which is feedwater flow demand value; the industrial control computer receives liquid level set value, liquid level measured value and steam-water mismatch value through the analog output module; the industrial control computer sends feedwater flow demand value through the analog input module.

7. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The DCS control system directly realizes PID control of the steam generator liquid level through the controller, and the control program is designed by using ladder programming language; the control program comprises an input conversion module, a PID calculation module, an output conversion module and a register group; the input conversion module converts the 4-20 mA current analog signal into an actual liquid level value of 0-1; the output conversion module converts the control quantity output by the PID calculation module into a 4-20 mA current analog signal; the register group comprises a bit register and a word register, the bit register is used to process on-off quantity logic signals, and the word register is used to process integer data and arithmetic operations.

8. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The platform supports a fast control prototype mode, in which the control algorithm is deployed in the controller or the industrial control computer, runs the controller hardware model, and the controlled object is a steam generator simulation model; after the controller is designed and simulated and verified, the control program can be compiled and downloaded to the controller to perform closed-loop verification of the entire control system; when the control parameters or the model need to be adjusted, the next closed-loop verification can be directly performed after modification through the host computer or the industrial control computer.

9. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The platform supports a hardware-in-the-loop simulation mode, in which the controller, the distributed I / O system in the closed-loop control loop are hardware devices, and the controlled object is a steam generator simulation model, or the controller, the distributed I / O system and part of the actuator are hardware devices, and the rest are virtual devices; the hardware-in-the-loop simulation mode adopts modular programming and standard interface design.

10. The hardware-in-the-loop simulated steam generator level control system verification platform of claim 1, wherein, The industrial control computer supports complex intelligent control algorithms, which can replace traditional PID control algorithms; the platform is configured with a database for storing system operation data screened by a user, and the database supports data export; the host computer provides a visual human-computer interaction interface, and the user can monitor the state of each interface, define data curve display, observe the action process of the mechanism and call the reactor operation monitoring picture in real time.

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