Semi-hardware dynamic simulation platform of 3000L / h helium liquefier

Abstract

The invention relates to the technical field of system simulation, and discloses a semi-hardware dynamic simulation platform of a 3000L / h helium liquefier, which comprises an actual PLC control system, PLC hardware and an N I simulation machine, the control system is in communication connection with the PLC hardware, the PLC hardware is connected with the N I simulation machine through an N I hardware board card, and the N I simulation machine is provided with a simulation model of the 3000L / h helium liquefier. According to the semi-hardware dynamic simulation platform of the 3000 L / h helium liquefier, the thermodynamic performance of the 3000 L / h helium liquefier can be known in advance, the dynamic thermal load of the 3000 L / h helium liquefier can be simulated, control program pre-verification can be carried out, the main control logic of the 3000 L / h helium liquefier can be debugged, and performance pre-estimation of the 3000 L / h helium liquefier in different working modes can be carried out. A reference basis is provided for actual operation adjustment of the 3000 L / h helium liquefier, and an operator is trained. According to the semi-hardware dynamic simulation platform, actual PLC hardware is adopted, and the field real signal environment of the 3000 L / h helium liquefier can be simulated to the maximum extent.

Description

Technical Field

[0001] The invention relates to the technical field of system simulation, and in particular to a semi-hardware dynamic simulation platform for a 3000L / h helium liquefier. Background Art

[0002] With the development of science and technology, large cryogenic systems have been widely used in cutting-edge fields such as nuclear fusion, high-energy physics and superconducting systems, such as the Large Hadron Collider (LHC) of CERN, the International Thermonuclear Experimental Reactor (I TER) and the National Advanced Nuclear Fusion Experimental Superconducting Tokamak (EAST). At present, more than half of my country's large scientific facilities require the support of cryogenic technology, and eight systems under construction or in pre-research need to be equipped with large helium cryogenic systems.

[0003] The development of the 3000L / h helium liquefier can meet the demand for large-scale helium refrigerators / helium liquefiers for larger-scale helium production and large scientific projects.

[0004] The 3000L / h helium liquefier system is complex and has high power consumption, so it is not suitable to improve its significant efficiency and stability through a large number of experiments. Dynamic simulation of the 3000L / h helium liquefier can simulate the dynamic heat load under different working modes and variable conditions, reduce the thermal shock to the liquefier, and estimate the performance of the 3000L / h helium liquefier under different working modes, providing key guidance for the design of the 3000L / h helium liquefier and the design of the cryogenic distribution system.

[0005] The OTS (Operation Training System) operation training system combines dynamic simulation and measurement and control system development technology to develop a front-end user operation interface, which is convenient for understanding the characteristics of the entire cryogenic system and conducting operation training for staff before the system is operated. Developing and utilizing the operation training system to train operators can avoid putting actual equipment in a dangerous situation. The operation training system can be operated in certain special working conditions without worrying about serious consequences. For operators, they cannot distinguish whether they are facing a real system or a simulated system when facing the HMI human-machine interface.

[0006] The 3000L / h helium liquefier is a complex system with nonlinearity, multivariables, and large hysteresis. It is impossible to directly obtain an accurate mathematical model and transfer function, and it is difficult to conduct direct control research. Summary of the invention

[0007] Based on this, it is necessary to address the technical problem of poor safe and stable operation of the 3000L / h helium liquefier in the prior art, and propose a semi-hardware dynamic simulation platform for the 3000L / h helium liquefier. The semi-hardware dynamic simulation platform for the 3000L / h helium liquefier includes: an actual PLC control system, PLC hardware, and a NI simulator. The control system is connected to the PLC hardware for communication, and the PLC hardware is connected to the NI simulator through an NI hardware board. The NI simulator is deployed with a simulation model of the 3000L / h helium liquefier, wherein the 3000L / h helium liquefier is modified based on a superfluid helium refrigerator, and the 3000L / h helium liquefier includes two self-developed four-stream heat exchanger component models;

[0008] The simulation method of the simulation platform comprises:

[0009] The actual PLC control system is connected to the NI hardware board of the NI simulator through the PLC hardware to collect the standard electrical signal output by the NI hardware board, wherein the standard electrical signal is generated based on the simulation model of the 3000L / h helium liquefier deployed in the NI simulator;

[0010] By setting the values ​​of input parameters on the human-machine interface of the control system's host computer, various commands and parameters are output to the simulation model to enable the control system based on the actual PLC to collect standard electrical signals, and using the NI simulation machine as an intermediate medium to interact with the simulation model. The hardware addresses of the input and output variables in the control program written based on the PLC hardware are the same as the hardware addresses of the input and output variables in the control program of the control system under the real field signal environment.

[0011] The semi-hardware dynamic simulation platform of a 3000L / h helium liquefier proposed by the present invention comprises: a control system of an actual PLC, PLC hardware, and a NI simulation machine, wherein the control system is communicatively connected with the PLC hardware, the PLC hardware is connected with the NI simulation machine through an NI hardware board, and the NI simulation machine is deployed with a simulation model of a 3000L / h helium liquefier; the control system of the actual PLC is connected with an NI hardware board of the NI simulation machine through the PLC hardware, and a standard electrical signal output by the NI hardware board is collected, wherein the standard electrical signal is generated based on the simulation model of the 3000L / h helium liquefier deployed in the NI simulation machine; by setting the value of the input parameter on the human-machine interface of the upper computer of the control system, various commands and parameters are output to the simulation model, so as to realize the control system based on the actual PLC to collect the standard electrical signal, and the NI simulation machine is used as an intermediate medium to perform data interaction with the simulation model, wherein the hardware addresses of the input and output variables in the control program written based on the PLC hardware are the same as the hardware addresses of the input and output variables in the control program of the control system under the real field signal environment. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier proposed in the present invention can understand the thermodynamic properties of the 3000L / h helium liquefier in advance, simulate the dynamic heat load of the 3000L / h helium liquefier, pre-verify the control program, debug the main control logic of the 3000L / h helium liquefier, and perform performance estimation of the 3000L / h helium liquefier under different working modes. It provides a reference basis for the actual operation adjustment of the 3000L / h helium liquefier and trains operators. This semi-hardware dynamic simulation platform uses actual PLC hardware and can simulate the real on-site signal environment of the 3000L / h helium liquefier to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] in:

[0014] Figure 1 A simplified flow chart of a 3000L / h helium liquefier in one embodiment;

[0015] Figure 2 A technical architecture schematic diagram of a semi-hardware dynamic simulation platform for a 3000L / h helium liquefier of the present invention;

[0016] Figure 3It is another technical architecture schematic diagram of the semi-hardware dynamic simulation platform of the 3000L / h helium liquefier of the present invention. DETAILED DESCRIPTION

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0018] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1 As shown, Figure 1 A simplified flow chart of a 3000L / h helium liquefier in a semi-hardware dynamic simulation platform of a 3000L / h helium liquefier provided in an embodiment of the present invention, wherein the semi-hardware dynamic simulation platform of the 3000L / h helium liquefier comprises an actual PLC control system, PLC hardware, and a NI simulator, wherein the control system is communicatively connected to the PLC hardware, the PLC hardware is connected to the NI simulator via a NI hardware board, and the NI simulator is deployed with a simulation model of a 3000L / h helium liquefier, wherein the 3000L / h helium liquefier is modified based on a superfluid helium refrigerator, and the 3000L / h helium liquefier comprises two self-developed four-stream heat exchanger component models;

[0021] The simulation method of the simulation platform comprises:

[0022] The actual PLC control system is connected to the NI hardware board of the NI simulator through the PLC hardware to collect the standard electrical signal output by the NI hardware board, wherein the standard electrical signal is generated based on the simulation model of the 3000L / h helium liquefier deployed in the NI simulator;

[0023] The standard electrical signals include but are not limited to: 0-20mA current signal, 4-20mA current signal, 0-10V voltage signal, -10V-+10V voltage signal, 0-5V voltage signal, 1-5V voltage signal.

[0024] By setting the values ​​of input parameters on the human-machine interface of the control system's host computer, various commands and parameters are output to the simulation model to enable the control system based on the actual PLC to collect standard electrical signals, and using the NI simulation machine as an intermediate medium to interact with the simulation model. The hardware addresses of the input and output variables in the control program written based on the PLC hardware are the same as the hardware addresses of the input and output variables in the control program of the control system under the real field signal environment.

[0025] In this embodiment, the control system may refer to a control system composed of a host computer and based on an actual PLC, which is directly connected to the NI hardware board using I / O and hard-wired to collect standard electrical signals output by the NI hardware board, and can output various commands and parameters to the simulation model by setting the values ​​of input parameters on the human-machine interface of the control system host computer. In other words, the control system based on the actual PLC collects standard electrical signals and uses the NI simulation machine as an intermediate medium to interact with the simulation model.

[0026] in, Figure 1 The following is a simplified flow chart of the 3000L / h helium liquefier. The 3000L / h helium liquefier is an improved Claude cycle, and its working process is as follows:

[0027] (1) The normal temperature and high pressure helium discharged from the high pressure compressor CH enters the cold box;

[0028] (2) After the high-pressure helium enters the cold box, it is cooled to a certain temperature by the reflux cold helium through the first-stage heat exchanger HEX1, and then a portion of it enters the second-stage heat exchanger HEX2 to be pre-cooled to 80K by liquid nitrogen. HEX2 is a heat exchanger immersed in a liquid nitrogen tank D3100 and uses immersion liquid nitrogen pre-cooling.

[0029] (3) The remaining high-pressure main line helium is pre-cooled and enters the 80K cryogenic adsorber group to remove impurity gases such as oxygen and nitrogen in the helium. It is then cooled by the reflux cold helium through the fourth-stage heat exchanger HEX4. A portion of the helium enters the second turbine expansion unit E21 and E22 through pipeline 1 and is cooled from 75K to 50K. The outlet gas of the second turbine expansion unit is returned to the medium pressure, countercurrently passes through the heat exchangers HEX5, HEX4, HEX3 and HEX1, and enters the intake port of the high-pressure compressor unit CH.

[0030] (4) After the high-pressure main gas passes through the sixth-stage heat exchanger HEX6, a portion of it enters the third turboexpander units E31 and E32, where it is cooled from 23K to 15K. The helium at the outlet of the third turboexpander unit is returned to the medium pressure, countercurrently passes through the heat exchangers HEX7, HEX6, HEX5, HEX4, HEX3 and HEX1, and enters the suction port of the high-pressure compressor unit CH;

[0031] (5) After the remaining high-pressure main gas passes through the seventh-stage heat exchanger HEX7, it enters the 20K low-temperature adsorber to remove impurity gases such as argon in the helium. A portion of the helium enters the fourth turboexpander units E41 and E42, where it is cooled from 14K to 6K. The outlet gas of the fourth turboexpander unit is returned to low pressure, countercurrently passes through the heat exchangers HEX8, HEX7, HEX6, HEX5, HEX4, HEX3 and HEX1, and enters the suction port of the low-pressure compressor unit CL;

[0032] (6) After the remaining high-pressure main gas passes through the eighth-stage heat exchanger HEX8, it passes through the last-stage turbine E51 and enters the ninth-stage heat exchanger HEX9 to exchange heat with the return cold helium gas. The high-pressure main gas then reaches a supercritical state. The supercritical helium gas is throttled into gas-liquid two-phases by the throttle valve CV24. The liquid phase accumulates in D4300, and the gas phase is returned to the low-pressure pipeline through the return valve CV25. It countercurrently passes through the heat exchangers HEX9, HEX8, HEX7, HEX6, HEX5, HEX4, HEX3 and HEX1, and enters the low-pressure compressor unit CL suction port to complete the entire cycle.

[0033] It should be noted that Figure 1 The process diagram of a 3000L / h helium liquefier is based on the 18kW@4.5K&4kW@2K superfluid helium refrigerator, which is a dual-purpose 3000L / h helium liquefier. This article only introduces the functions of the liquefier. Although the other load test cold box, negative pressure circuit and other facilities exist, they are not used in this liquefier, so they are not introduced.

[0034] In this embodiment, the simulation model of the 3000L / h helium liquefier can be established based on the dynamic simulation software Ecos imPro, and compiled. It should be noted that when establishing the simulation model of the 3000L / h helium liquefier based on the process diagram of the 3000L / h helium liquefier, it is necessary to develop the required component models. For example, the four-stream heat exchanger model and other models that do not exist in the cryogenic component library need to be independently developed. Only two self-developed four-stream heat exchanger component models are used in the 3000L / h helium liquefier simulation model. Figure 1 The remaining three four-stream heat exchangers can be treated as three-stream heat exchangers during simulation. Because the 3000L / h helium liquefier is a modification based on the superfluid helium refrigerator, it is a dual-purpose machine. The liquid nitrogen pre-cooling circuit uses the negative pressure channels of the first and second four-stream heat exchangers, that is, the negative pressure channels of HEX1 and HEX3 are used for the return of saturated nitrogen vapor (HEX1 and HEX3 have been modified). There is no fluid in the negative pressure channels of the remaining three four-stream heat exchangers, and the high and low pressure temperature differences are large. It is not easy to converge during simulation calculations, and it needs to be processed into a three-stream heat exchanger model.

[0035] In one embodiment, the operation results of the simulation model are displayed in the human-machine interface of the host computer, and the operation results include input data, and the input data include each compressor start signal, each regulating valve opening, each switch valve opening, each electric heater power, and each PID automatic signal in the simulation model.

[0036] In this embodiment, specifically, the input data includes the high-pressure compressor start signal, the low-pressure compressor start signal. Each PID of the compressor station is automatically put into operation, each PID of the turbine expansion unit is automatically put into operation, each PID in the liquid helium dewar D4300 is automatically put into operation, and each PID in the liquid nitrogen tank D3100 is automatically put into operation. The high-pressure compressor slide valve signal, the low-pressure compressor slide valve signal. The opening of each regulating valve in the 3000L / h helium liquefier, the opening of each switch valve. The power of the internal electric heater of D3100 and D4300.

[0037] In one embodiment, the operation results include output data, and the output data includes the temperatures before and after each stage of the heat exchanger, the pressures before and after each stage of the heat exchanger, and the flow rates before and after each stage of the heat exchanger in the simulation model, the opening of each valve, the inlet and outlet temperatures of each valve, the inlet and outlet pressures of each valve, and the inlet and outlet flow rates of each valve, the inlet and outlet temperatures of each turbine, the inlet and outlet pressures of each turbine, and the inlet and outlet flow rates of each turbine, the speeds of each turbine, and the efficiency of each turbine, the temperatures of each gas-liquid separator, the pressures of each gas-liquid separator, and the liquid levels of each gas-liquid separator, the inlet and outlet flow rates of each gas-liquid separator, and the power of the electric heater inside each gas-liquid separator.

[0038] In this embodiment, specifically, the output data includes simulation time t ime, error information error (optional, if the system has), high pressure compressor / low pressure compressor inlet and outlet temperature, high pressure compressor / low pressure compressor inlet and outlet pressure, high pressure compressor / low pressure compressor inlet and outlet flow, high pressure compressor / low pressure compressor frequency, high pressure compressor / low pressure compressor slide valve, each regulating valve opening, each regulating valve inlet and outlet temperature, each regulating valve inlet and outlet pressure, each regulating valve inlet and outlet flow. Each switch valve opening, each switch valve inlet and outlet temperature, each switch valve inlet and outlet pressure, each switch valve inlet and outlet flow, each turbine inlet and outlet temperature, each turbine inlet and outlet pressure, each turbine inlet and outlet flow, each turbine speed, each turbine efficiency, each heat exchanger front and rear temperature, each heat exchanger front and rear pressure, each heat exchanger front and rear flow. D3100 / D4300 temperature, D3100 / D4300 pressure, D3100 / D4300 liquid level, D3100 / D4300 inlet and outlet flow. D3100 / D4300 internal electric heater power.

[0039] In one embodiment, the simulation model of the 3000L / h helium liquefier includes a simulation time component and an error information component; the simulation time component is obtained by encapsulating the internal variable simulation time when establishing the simulation model; the error information component is obtained by encapsulating the internal variable error information when establishing the simulation model; the simulation time component outputs a simulation time value, the variable type is real, and the analog output; the error information component outputs an error information value, the variable type is real, and the analog output.

[0040] In this embodiment, it can be understood that when establishing the simulation model of the 3000L / h helium liquefier, the internal variables simulation time t ime and error information error are respectively encapsulated into available components. The internal variable simulation time t ime is encapsulated into a simulation time component. The internal variable error information error is encapsulated into an error information component. The simulation time component outputs the simulation time value of the system, the variable type is real, and the analog output. The error information component outputs the error information value of the system, the variable type is real, and the analog output. The simulation time component and the error information component do not need to be connected to the main loop of the simulation model of the 3000L / h helium liquefier. It is only necessary to place the simulation time component and the error information component and the main loop model of the 3000L / h helium liquefier simulation model in the same screen. After the compilation is passed, it can run smoothly.

[0041] In one embodiment, the simulation model of the 3000L / h helium liquefier includes a four-stream heat exchanger model, which is a four-stream heat exchanger simulation component model developed under the conditions that the hot fluid only exchanges heat with the cold fluid and the hot fluid exchanges heat with the cold fluid through the metal wall. In the four-stream heat exchanger simulation component model, the high-pressure and high-temperature fluid flows from left to right, the medium-pressure and low-temperature fluid flows from right to left, the low-pressure and low-temperature fluid flows from right to left, and the negative-pressure and low-temperature fluid flows from right to left.

[0042] In this embodiment, the simulation model of the 3000L / h helium liquefier includes a four-stream heat exchanger model. Two self-developed four-stream heat exchanger models are used in the simulation model of the 3000L / h helium liquefier. The 3000L / h helium liquefier can be composed of a compressor station, a cold box, a turbine expansion unit, a heat exchanger and a gas-liquid separator.

[0043] In one embodiment, referring to Figure 2 , the NI simulator runs on the Windows operating system, and the simulation model encapsulated into an fmu file runs on the NI simulator, wherein a third-party laboratory management software is used on the NI simulator to monitor the running status of the simulation model. Specifically, a simulation model of a 3000L / h helium liquefier is first established, and after the simulation model is compiled, a part is generated. After the part is successfully validated, an experiment is established, and EL language code is written into the experiment, and the experiment is compiled and run. A deck platform is generated based on the EL experiment code; the deck platform is used to encapsulate the simulation model into an fmu file, and after the simulation model is encapsulated into an fmu file, it is placed in the NI simulator.

[0044] In this embodiment, the simulation model is encapsulated into an fmu file using the deck platform, and an fmu file type that can interact with third-party software is selected. The fmu file generated in this way can be deployed by third-party software and interact with other third-party software.

[0045] After the simulation model is packaged into an fmu file, it is placed in the NI simulator. The generated fmu file is deployed using third-party laboratory management software such as Ver i Stand. After successful deployment, standard electrical signals are generated and input and output through NI hardware boards.

[0046] The standard electrical signals include but are not limited to: 0-20mA current signal, 4-20mA current signal, 0-10V voltage signal, -10V-+10V voltage signal, 0-5V voltage signal, 1-5V voltage signal.

[0047] The control system based on the actual PLC uses I / O direct connection and hard wiring to connect with the NI hardware board to collect the standard electrical signals output by the NI hardware board. At the same time, various commands and parameters can be output to the simulation model by setting the values ​​of the input parameters on the human-machine interface of the control system host computer. In other words, the control system based on the actual PLC collects standard electrical signals and uses the NI simulation machine as an intermediate medium to interact with the simulation model.

[0048] The NI simulator runs on the Windows operating system, and the simulation model packaged as an fmu file runs on the NI simulator. At the same time, a third-party laboratory management software such as VeriStand is used on the NI simulator to monitor the running status of the dynamic simulation model. For example, the control variable Mode lCommand can be used on the VeriStand workspace interface to control the start, pause and stop of the simulation model.

[0049] Based on the actual PLC control system, the human-machine interface runs on the upper workstation / PC. Through the human-machine interface on the upper computer, commands can be sent to control the simulation model and monitor various process parameters of the simulation model. The actual PLC collects standard electrical signals. Based on the control program written by the actual PLC, the hardware addresses of the input and output variables can be the same as the hardware addresses of the input and output variables in the control program of the control system under the real field signal environment, that is, to simulate the real field signal environment to the greatest extent.

[0050] In one embodiment, referring to Figure 3NI simulator runs on the Linux operating system, and the simulation model runs on the NI simulator. Meanwhile, the third-party laboratory management software is used on the host PC (Windows system) to monitor the running status of the simulation model. Specifically, a simulation model of a 3000L / h helium liquefier is first established. After the simulation model is compiled, a part is generated. After the part is successfully validated, an experiment is established, EL language code is written into the experiment, the experiment is compiled and run, and a deck platform is generated based on the EL experiment code. The deck platform is used to encapsulate the simulation model into an fmu file that can be run under the Linux operating system. After the simulation model is encapsulated into an fmu file that can be run under the Linux operating system, the fmu file is deployed to the NI simulator of the Linux system in the host PC of the Windows system for operation.

[0051] In this embodiment, the deck platform is used to encapsulate the simulation model into an fmu file that can be run under the Linux operating system, and the fmu file type that can interact with third-party software is selected. The fmu file generated in this way can be deployed by third-party software and interact with other third-party software.

[0052] After the simulation model is encapsulated into an fmu file that can run under the Linux operating system, the fmu file is deployed to the lower computer, namely the NI simulator (Linux system), in the upper PC (Windows system) using third-party laboratory management software such as VeriStand. After successful deployment, standard electrical signals are generated and input and output through the NI hardware board. Compared with the Windows system, the Linux system has better real-time performance. Therefore, the simulation model runs in the NI simulator (Linux system), and the real-time performance is better. The data interaction between the simulation model and the control system is faster and smoother. The control system based on the actual PLC adopts I / O direct connection and hard wiring to connect with the NI hardware board to collect the standard electrical signals output by the NI hardware board. At the same time, various commands and parameters can be output to the simulation model by setting the value of the input parameters on the human-machine interface of the control system host computer. In other words, the control system based on the actual PLC collects standard electrical signals and uses the NI simulator as an intermediate medium to interact with the simulation model.

[0053] The standard electrical signals include but are not limited to: 0-20mA current signal, 4-20mA current signal, 0-10V voltage signal, -10V-+10V voltage signal, 0-5V voltage signal, 1-5V voltage signal.

[0054] The NI simulator runs on the Linux operating system. The simulation model encapsulated as an fmu file is deployed to the NI simulator (Linux system) using a third-party laboratory management software such as Veristand on the host PC (Windows system) to run. At the same time, a third-party laboratory management software such as Veristand is used on the host PC (Windows system) to monitor the running status of the dynamic simulation model. For example, the control variable Mode l Command can be used on the Veristand workspace interface to control the start, pause and stop of the simulation model.

[0055] Based on the actual PLC control system, the human-machine interface runs on another upper workstation / PC. Through the human-machine interface on another upper computer, commands can be sent to control the simulation model and monitor various process parameters of the simulation model. The actual PLC collects standard electrical signals. Based on the control program written by the actual PLC, the hardware addresses of the input and output variables can be the same as the hardware addresses of the input and output variables in the control program of the control system under the real field signal environment, that is, to simulate the real field signal environment to the greatest extent. The Linux operating system runs on the NI simulator, which has good real-time performance.

[0056] The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier proposed in this embodiment can understand the thermodynamic properties of the 3000L / h helium liquefier in advance, simulate the dynamic heat load of the 3000L / h helium liquefier, pre-verify the control program, debug the main control logic of the 3000L / h helium liquefier, and perform performance estimation of the 3000L / h helium liquefier under different working modes. Provide a reference basis for the actual operation and adjustment of the 3000L / h helium liquefier, and train operators. This semi-hardware dynamic simulation platform uses actual PLC hardware, which can simulate the real on-site signal environment of the 3000L / h helium liquefier to the greatest extent.

[0057] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0058] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A semi-hardware dynamic simulation platform for a 3000L / h helium liquefier, characterized in that: The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier includes: an actual PLC control system, PLC hardware, and a NI simulator. The control system is connected to the PLC hardware in communication. The PLC hardware is connected to the NI simulator via an NI hardware board. The NI simulator is deployed with a simulation model of the 3000L / h helium liquefier. The 3000L / h helium liquefier is modified based on a superfluid helium refrigerator. The 3000L / h helium liquefier includes two self-developed four-stream heat exchanger component models. The simulation method of the simulation platform comprises: The actual PLC control system is connected to the NI hardware board of the NI simulator through the PLC hardware to collect the standard electrical signal output by the NI hardware board, wherein the standard electrical signal is generated based on the simulation model of the 3000L / h helium liquefier deployed in the NI simulator; By setting the values ​​of input parameters on the human-machine interface of the control system's host computer, various commands and parameters are output to the simulation model to enable the control system based on the actual PLC to collect standard electrical signals, and using the NI simulation machine as an intermediate medium to interact with the simulation model. The hardware addresses of the input and output variables in the control program written based on the PLC hardware are the same as the hardware addresses of the input and output variables in the control program of the control system under the real field signal environment.

2. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 1, characterized in that: The operation results of the simulation model are displayed in the human-machine interface of the host computer, and the operation results include input data, and the input data include each compressor start signal, each regulating valve opening, each switch valve opening, each electric heater power, and each PID automatic signal in the simulation model.

3. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 2, characterized in that: The operation results include output data, and the output data include the temperatures before and after each stage of the heat exchanger, the pressures before and after each stage of the heat exchanger, and the flow rates before and after each stage of the heat exchanger in the simulation model, the opening of each valve, the inlet and outlet temperatures of each valve, the inlet and outlet pressures of each valve, and the inlet and outlet flow rates of each valve, the inlet and outlet temperatures of each turbine, the inlet and outlet pressures of each turbine, and the inlet and outlet flow rates of each turbine, the speeds of each turbine, and the efficiency of each turbine, the temperatures of each gas-liquid separator, the pressures of each gas-liquid separator, and the liquid levels of each gas-liquid separator, the inlet and outlet flow rates of each gas-liquid separator, and the power of the electric heater inside each gas-liquid separator.

4. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 3, characterized in that: The simulation model of the 3000L / h helium liquefier includes a simulation time component and an error information component; The simulation time component is obtained by encapsulating the internal variable simulation time when establishing the simulation model; the error information component is obtained by encapsulating the internal variable error information when establishing the simulation model; The output of the simulation time component is the simulation time value, the variable type is real, and the analog output; the output of the error information component is the error information value, the variable type is real, and the analog output.

5. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 1, characterized in that: The simulation model of the 3000L / h helium liquefier includes a four-stream heat exchanger model, which is a four-stream heat exchanger simulation component model developed under the conditions that the hot fluid only exchanges heat with the cold fluid and the hot fluid exchanges heat with the cold fluid through the metal wall. In the four-stream heat exchanger simulation component model, the high-pressure and high-temperature fluid flows from left to right, the medium-pressure and low-temperature fluid flows from right to left, the low-pressure and low-temperature fluid flows from right to left, and the negative-pressure and low-temperature fluid flows from right to left.

6. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 5, characterized in that: The 3000L / h helium liquefier consists of a compressor station, a cold box, a turbine expander unit, a heat exchanger and a gas-liquid separator.

7. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 6, characterized in that: The NI simulator runs a Windows operating system, and a simulation model encapsulated as an fmu file runs on the NI simulator. A third-party laboratory management software is used on the NI simulator to monitor the running status of the simulation model.

8. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 7, characterized in that: The steps of deploying the simulation model of the 3000L / h helium liquefier to the NI simulator include: Establish a simulation model of a 3000L / h helium liquefier. After the simulation model is compiled, a partition is generated. After the partition is successfully validated, establish an experiment, write EL language code in the experiment, compile and run the experiment, and generate a deck platform based on the EL experiment code. Using the deck platform, the simulation model is packaged into an fmu file. After the simulation model is packaged into an fmu file, it is placed in the NI simulation machine.

9. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 6, characterized in that: The NI simulator runs the Linux operating system, and the simulation model runs on the NI simulator. At the same time, a third-party laboratory management software is used on the host PC using the Windows system to monitor the running status of the simulation model.

10. The semi-hardware dynamic simulation platform of the 3000L / h helium liquefier according to claim 9, characterized in that: The steps of deploying the simulation model of the 3000L / h helium liquefier to the NI simulator include: Establish a simulation model of a 3000L / h helium liquefier. After the simulation model is compiled, a partition is generated. After the partition is successfully validated, establish an experiment, write EL language code in the experiment, compile and run the experiment, and generate a deck platform based on the EL experiment code. Using the deck platform, the simulation model is encapsulated into an fmu file that can be run under the Linux operating system. After the simulation model is encapsulated into an fmu file that can be run under the Linux operating system, the fmu file is deployed to the NI simulator of the Linux system in the host PC using the Windows system for execution.

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