LABVIEW-based pulsed neutron generator control system

Abstract

The invention discloses a pulsed neutron generator control system based on LabVIEW, and the system comprises a neutron generator industrial personal computer which operates a virtual human-computer interaction interface developed based on LabVIEW; the console core board carries a DSP main control chip and is embedded into a real-time operating system; the driving sampling board is connected with the console core board and is integrated with a signal conditioning circuit; the neutron generator industrial personal computer communicates with the console core board through a Modbus protocol, and controls and drives the sampling board to output control signals of the three independent power supply ion sources, the storage and the acceleration pole to the neutron tube; wherein the console core board generates three paths of PWM signals with the PWM frequency of 2.5 kHz and the step length of 8191, and the three paths of PWM signals are converted into analog control signals through the driving sampling board. According to the control system, the PWM control precision is greatly improved, the voltage control precision is improved to 0.012% (100% higher than that of a conventional scheme) through the combination of the 8191 step length (13-bit resolution) and the 2.5 kHz frequency, and the neutron yield fluctuation is controlled within + / -1.5%.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron generators, and in particular to a pulsed neutron generator control system based on LABVIEW. Background Art

[0002] A neutron tube is an electrically vacuum device consisting of an ion source, acceleration system, target, and gas pressure regulation system sealed within a ceramic or glass tube. The neutron tube, along with its matching reservoir power supply, ion source power supply, acceleration high-voltage power supply, and corresponding control and detection circuits, constitutes a small neutron generator. After years of development, portable, mobile, and miniaturized neutron generators have found widespread application in oil well logging, coal quality analysis, and medical treatment.

[0003] Existing pulsed neutron generators suffer from insufficient control precision. Conventional PWM control uses a conventional step size (e.g., 4096), resulting in a voltage control accuracy greater than 0.024%, leading to neutron yield fluctuations greater than ±5%. To address this issue, we propose a pulsed neutron generator control system based on LabVIEW. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide a pulsed neutron generator control system based on LABVIEW, which greatly improves the PWM control accuracy. By combining 8191 steps (13-bit resolution) with a 2.5kHz frequency, the voltage control accuracy is increased to 0.012% (a 100% increase compared to conventional solutions), and the neutron yield fluctuation is controlled within ±1.5%, which can effectively solve the problems in the background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a pulsed neutron generator control system based on LABVIEW, comprising: The neutron generator industrial computer runs a virtual human-computer interaction interface developed based on LabVIEW; The console core board is equipped with a DSP main control chip and embedded with a real-time operating system; A driving sampling board is connected to the console core board and integrates a signal conditioning circuit; The neutron generator industrial computer communicates with the console core board through the Modbus protocol, and controls the driving sampling board to output control signals of three independent power supply ion sources, storage and accelerating electrodes to the neutron tube; Among them, the console core board generates three PWM signals with a PWM frequency of 2.5kHz and a step size of 8191, which are converted into analog control signals by the driving sampling board.

[0006] As a preferred technical solution of the present invention, the virtual human-computer interaction interface is written in G language, and the human-computer interaction interface is divided into a control interface, a parameter setting interface, a data storage interface, and an instruction interface.

[0007] As a preferred technical solution of the present invention, the control interface mainly includes a storage adjustment panel, an ion source adjustment panel, an accelerating electrode adjustment panel, and an ion source trigger and synchronization pulse adjustment panel.

[0008] As a preferred technical solution of the present invention, the neutron generator industrial computer serves as the host, and the console core board serves as the slave.

[0009] As a preferred technical solution of the present invention, the system also includes a custom functional state machine, which adopts different control strategies according to the current state of the system, and the LabVIEW virtual human-computer interaction interface independently completes the protection and control of the pulsed neutron generator console.

[0010] As a preferred technical solution of the present invention, the custom function state machine has main modes including idle state, initialization state, memory adjustment, ion source adjustment, accelerating pole adjustment, register reading, three-way DA reading, six-degree AD reading, update state, automatic control and other states. During normal operation of the system, the current state will be used to determine the corresponding control strategy.

[0011] As a preferred technical solution of the present invention, a real-time operating system is embedded in the main control chip of the console core board.

[0012] The present invention also provides a pulse neutron yield control method, comprising the following steps: (1) Set the target voltage value of the memory power supply through the neutron generator industrial computer; (2) The core control board generates the corresponding PWM duty cycle signal, which is converted into an analog control voltage by the driver sampling board 3; (3) Adjust the memory power supply voltage to control the amount of deuterium and tritium ion ionization; (4) Indirectly control the neutron yield by adjusting the ion beam intensity.

[0013] The present invention also provides a computer-readable storage medium storing a LabVIEW program, which implements all steps of the above-mentioned pulse neutron yield control method when executed by a processor.

[0014] Compared with the existing technology, the beneficial effects of the present invention are: greatly improving PWM control accuracy. By combining 8191 steps (13-bit resolution) with a 2.5kHz frequency, the voltage control accuracy is increased to 0.012% (a 100% increase compared to conventional solutions), and the neutron yield fluctuation is controlled within ±1.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the system structure of the present invention; Figure 2 It is a schematic diagram of the use process of the present invention; Figure 3 is a schematic diagram of a virtual human-computer interaction interface of the present invention; Figure 4 This is a schematic diagram of the structure of the console core board of the present invention; Figure 5 This is a schematic diagram of the structure of the driving sampling plate of the present invention; Figure 6 Schematic diagram of the structure of the memory of the present invention; Figure 7 Schematic diagram of the structure of the ion source of the present invention; Figure 8 Schematic diagram of the structure of the accelerating electrode of the present invention; Figure 9 This is a schematic diagram of the functions and priorities of each thread in the main control chip of the present invention; Figure 10 This is a flowchart of the program in the main control chip of the present invention; Figure 11 This is a schematic diagram of the trigger pulse and synchronization pulse test of the present invention; Figure 12 This is a neutron yield stability counting diagram of the present invention; Figure 13 Schematic diagram of the structure of the neutron tube of the present invention. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making creative efforts are within the scope of protection of the present invention.

[0017] See also Figure 1-13 The present invention provides a technical solution: a pulsed neutron generator control system based on LABVIEW, comprising: Neutron generator industrial computer 1, running a virtual human-computer interaction interface developed based on LabVIEW; Console core board 2, equipped with a DSP main control chip and embedded with a real-time operating system; Drive sampling board 3, connected to the console core board 2 and integrated with signal conditioning circuit; The neutron generator industrial computer 1 communicates with the console core board 2 via the Modbus protocol, and controls the sampling board 3 to output control signals of the three independent power supply ion source 5, the storage 6 and the accelerating electrode 7 to the neutron tube 8; The console core board 2 generates three PWM signals with a PWM frequency of 2.5 kHz and a step size of 8191, which are converted into analog control signals by the driving sampling board 3 .

[0018] This application is based on LabVIEW industrial computer software and uses G language to write the human-computer interaction interface of the pulse neutron generator control system. The overall control system adopts a producer-consumer structure model and uses a multi-threaded structure to complete data exchange.

[0019] Furthermore, the human-computer interaction interface is divided into a control interface, a parameter setting interface, a data storage interface, and an instruction interface; the control interface mainly includes a storage adjustment panel, an ion source adjustment panel, an accelerating electrode adjustment panel, an ion source trigger and synchronous pulse adjustment panel, and a one-button mode switching button.

[0020] Furthermore, in the human-computer interaction interface: develop an automatic reconnection function in case of disconnection, so that there is no need to restart the control interface in the event of a fault, and complete system self-checking; develop an anti-misoperation function, add start, stop, setting, status, indicator light and exit controls; develop three-way power supply oscilloscope, power supply data storage, time recording and other functions.

[0021] Utilizing LabVIEW library functions and FreeModbus communication protocol, the host computer LabVIEW virtual instrument serves as the host, and the pulsed neutron generator console serves as the slave.

[0022] An XML-based data file is created in LabVIEW to adapt to neutron generator consoles with different internal architectures.

[0023] The system also includes a custom functional state machine that adopts different control strategies according to the current state of the system. The LabVIEW virtual human-computer interaction interface independently completes the protection and control of the pulsed neutron generator console. A real-time operating system is embedded in the pulsed neutron generator main control chip, which uses the FreeModbus protocol to communicate with the host computer LabVIEW control interface.

[0024] The main control board and sampling driver board are used to complete the regulation of three-way power supply, six-way data sampling, and output trigger pulse signals and synchronous pulse signals.

[0025] Furthermore, in order to improve the control accuracy of the three PWM signals, the PWM step size is set to 8191 and the frequency is 2.5 kHz. The PWM step size is the number of high-level duty cycles of the PWM wave. Each step size can be approximately equal to the power supply control accuracy. The three PWM signals are converted into DC signals through low-pass filters, and the DC signals are used to control the corresponding power supply voltages. Furthermore, the three PWM signals are respectively passed through an optocoupler isolator, a voltage follower, an active second-order low-pass filter, and a voltage follower to complete the PWM wave conversion to a DA signal, thereby realizing the control of the three power supplies.

[0026] Furthermore, the sampling signal is sent to the optocoupler isolation circuit. Since the optocoupler isolation circuit will generate high-frequency noise, the isolated signal is filtered and then sent to the main control chip. Furthermore, the signals of the three power supplies are sampled through a differential circuit to suppress common-mode interference, and then the collected signals are filtered.

[0027] Furthermore, in order to make the sampling signal within the linear working range of the sampling circuit, the signal needs to be divided into two voltages. High-precision, low-temperature drift metal film precision resistors are used in the circuit for voltage division. Furthermore, the trigger pulse signal is directly sent to the 0-2000V ion source power supply after being isolated by an optical coupler, and is used to generate a pulse power supply with a frequency of 0-20kHZ. The synchronous pulse signal is sent to the neutron detector for detecting neutrons.

[0028] Optionally, the signal conditioning circuit for driving the sampling board includes cascade-connected: Optocoupler isolator, which receives PWM signal and realizes electrical isolation; Voltage follower for impedance matching; Active second-order low-pass filter to convert PWM signal into DC signal; The secondary voltage follower outputs the control voltage of 0-3V memory power supply, 0-2000V ion source power supply, and 0-110kV accelerating electrode power supply.

[0029] The power signal conversion circuit mostly uses single-stage RC filtering, with output ripple >100mV, affecting the ion source beam stability: an active second-order low-pass filter (-40dB / dec roll-off) suppresses the output ripple to <10mV, improving the ion source beam stability by 30%. Example

[0030] Based on LabVIEW industrial computer software, the virtual human-computer interaction interface of the pulsed neutron generator control system was written in G language; Serial communication: realize communication with the core board, the control interface acts as a Modbus host, and uses the Modbus library functions in the LabVIEW DSC component.

[0031] Program structure: The program uses message queues to implement data interaction between event triggering threads and event processing threads, making the program structure concise, easy to optimize, and easy to expand.

[0032] Read and write data: read and write registers in the Modbus protocol, namely AD sampling data, ion source pulse frequency and duty cycle, synchronization pulse frequency and duty cycle, and the frequency and duty cycle of the three-way PWM of the control power supply.

[0033] Data recording: Read the parameter information on the core board in real time and store it in the data file, and classify and store parameter configuration, power settings, power data and other information.

[0034] Configuration program: stores information related to serial communication and generator data logging in the form of XML documents.

[0035] Overload alarm: Real-time monitoring of the data parameters of the three power supplies of the neutron generator console, setting safety thresholds, and adding a red alarm and a mechanism to disable the operation button.

[0036] Waveform display: Develop a three-way power supply monitor to dynamically monitor the working status of the three-way power supply of the neutron generator.

[0037] Filtering algorithm: Use the median average filtering algorithm to process the three-way power supply voltage and current information to prevent occasional pulse interference from affecting the data.

[0038] Control algorithm: Add PID control algorithm, fuzzy control algorithm, neural network control algorithm and other algorithm modules.

[0039] PID control algorithm to adjust the power supply voltage closed-loop parameters; Fuzzy control algorithm to handle nonlinear operating fluctuations; Neural network algorithm, autonomous learning to optimize neutron yield; The algorithm automatically selects an execution strategy based on the power stability indicator.

[0040] The core control board consists of DSP chip, power supply, serial communication circuit, PWM output circuit, indicator light circuit and AD acquisition circuit. Output PWM signals to control three power supplies, with a PWM frequency of 2.5kHz.

[0041] Collect the voltage and current signals of the power supply, and the signal range is 0-3V.

[0042] The control console and the industrial computer communicate with each other via serial communication at a rate of 9600.

[0043] Outputs a trigger signal acting on the ion source power supply, that is, a DC signal or a pulse signal.

[0044] The synchronous signal of the output pulse signal has the same frequency and adjustable phase. The frequency range is 0-20kHz. It is mainly used in neutron detectors for energy spectrum analysis.

[0045] The driver sampling board consists of a voltage divider circuit, a power supply circuit, a low-pass filter, an amplifier circuit, and an isolation circuit. The functions of the driver sampling board are as follows: The optocoupler isolation circuit is used to introduce three-way PWM signals into the driver sampling board.

[0046] The three PWM signals are converted into DC signals through low-pass filters respectively, and the DC signals are used to control the corresponding power supply voltage.

[0047] In order to make the sampling signal within the linear working range of the sampling circuit, the signal needs to be voltage-divided. The circuit uses high-precision, low-temperature drift metal film precision resistors for voltage division.

[0048] The signals of the three power supplies are sampled through a differential circuit to suppress common-mode interference, and then the collected signals are filtered.

[0049] The sampling signal is sent to the optocoupler isolation circuit. Since the optocoupler isolation circuit will generate high-frequency noise, the isolated signal is filtered and then sent to the microcontroller.

[0050] The upper computer labVIEW human-computer interaction interface communicates with the lower computer core board through the serial port, sending control instructions to the main control. The main control chip adjusts three PWM waves, passes through isolation and filtering circuits, and outputs three DA signals. After being connected to the adjustment terminals of the three power supplies, they can generate 0-3V storage power supply, 0-2000V ion source pulse power supply, and 0-110kV accelerating electrode power supply respectively. The three power supplies act together on the neutron tube.

[0051] The main control chip outputs an ion source trigger pulse signal and a synchronization pulse signal. When the ion source trigger signal is high, the neutron tube operates in a continuous neutron mode. When the ion source trigger signal is a pulse signal, the neutron tube operates in a pulsed neutron mode, and the synchronization pulse acts on the He-3 detector to capture neutrons.

[0052] By calling control algorithms with different strategies and adjusting the size of the storage power supply voltage, the number of deuterium and tritium ions ionized by the ion source power supply is indirectly affected, and finally the ion beam current bombarding the target is affected, so as to achieve the purpose of regulating neutron output.

[0053] Any undisclosed portions of the present invention are prior art, and their specific structures, materials, and operating principles will not be described in detail. Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pulsed neutron generator control system based on LABVIEW, characterized in that: include: Neutron generator industrial computer (1), running a virtual human-computer interaction interface developed based on LabVIEW; The console core board (2) is equipped with a DSP main control chip and embedded with a real-time operating system; A driving sampling board (3) is connected to the console core board (2) and integrates a signal conditioning circuit; The neutron generator industrial control computer (1) communicates with the console core board (2) via the Modbus protocol, and controls the driving sampling board (3) to output control signals of three independent power supply ion sources (5), storage (6) and accelerating electrode (7) to the neutron tube (8); The console core board (2) generates three PWM signals with a PWM frequency of 2.5kHz and a step length of 8191, which are converted into analog control signals by the driving sampling board (3).

2. The pulsed neutron generator control system based on LABVIEW according to claim 1, characterized in that: The virtual human-computer interaction interface is written in G language, and the human-computer interaction interface is divided into a control interface, a parameter setting interface, a data storage interface, and an instruction interface.

3. The pulsed neutron generator control system based on LABVIEW according to claim 2, characterized in that: The control interface mainly includes a storage adjustment panel, an ion source adjustment panel, an accelerating electrode adjustment panel, and an ion source trigger and synchronous pulse adjustment panel.

4. The pulsed neutron generator control system based on LABVIEW according to claim 1, characterized in that: The neutron generator industrial control computer (1) serves as a host, and the console core board (2) serves as a slave.

5. The pulsed neutron generator control system based on LABVIEW according to claim 1, characterized in that: It also includes a custom functional state machine that adopts different control strategies according to the current state of the system. The LabVIEW virtual human-computer interaction interface independently completes the protection and control of the pulsed neutron generator console.

6. The pulsed neutron generator control system based on LABVIEW according to claim 5, characterized in that: The custom function state machine has main modes including idle state, initialization state, memory adjustment, ion source adjustment, accelerating pole adjustment, register reading, three-way DA reading, six-degree AD reading, update state, automatic control and other states. During normal operation of the system, the current state will be used to determine the corresponding control strategy.

7. The pulsed neutron generator control system based on LABVIEW according to claim 1, characterized in that: A real-time operating system is embedded in the main control chip of the console core board (2).

8. A pulse neutron yield control method, applied to the system according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Setting the target voltage value of the power supply of the memory (6) through the neutron generator industrial computer (1); (2) The core control board (2) generates the corresponding PWM duty cycle signal, which is converted into an analog control voltage by the driver sampling board (3); (3) Adjust the memory power supply voltage to control the amount of deuterium and tritium ion ionization; (4) Indirectly control the neutron yield by adjusting the ion beam intensity.

9. A computer-readable storage medium storing a LabVIEW program, characterized in that: When the program is executed by a processor, all steps of the pulse neutron yield control method according to claim 8 are implemented.

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