Signal simulator for nuclear power station loose part monitoring system

Abstract

The invention discloses a signal simulator for a nuclear power station loose component monitoring system, and relates to the technical field of nuclear power station equipment monitoring, a man-machine interaction module receives signal parameters of an impact signal to be simulated by the signal simulator, and a controller controls a signal generation module to generate the signal parameters, the method comprises the following steps: generating a sine wave basic signal with a frequency corresponding to a signal parameter through a direct digital frequency synthesizer, converting the sine wave basic signal into an impact pulse with a width corresponding to the signal parameter through a pulse forming network, and carrying out frequency spectrum shaping on the impact pulse through a filter corresponding to the material of a to-be-simulated loose component. And finally, the impact pulse after frequency spectrum shaping is adjusted to an amplitude corresponding to a signal parameter through a gain amplification circuit, and a simulated impact signal is obtained. According to the invention, different signal characteristics of the impact signal generated by the impact of the loose part can be simulated from multiple angles, and the simulation precision of the impact signal generated by the impact of the loose part is improved.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant equipment monitoring technology, and in particular to a signal simulator for a nuclear power plant loose component monitoring system. Background Technology

[0002] Currently, nuclear power plant Loose Parts Monitoring Systems (LPMS) collect impact signals generated by the impact of loose or detached parts (such as bolts, gaskets, and maintenance tools) inside the equipment to provide early warning of equipment failures. To ensure the accuracy of LPMS, it is necessary to periodically use a signal simulator to reproduce impact signals with different characteristics to verify the system's sensitivity and recognition capabilities.

[0003] In existing technologies, loose component monitoring systems typically use general signal generators to produce standard vibration signals for debugging and calibration. However, general signal generators can only produce standard sine waves, and the frequency components of the signal generated in a single instance are singular, which cannot accurately simulate impact signals and is difficult to meet the debugging and verification requirements of loose component alarm algorithms. Summary of the Invention

[0004] Therefore, it is necessary to provide a signal simulator for a nuclear power plant loose component monitoring system to address the aforementioned technical problems.

[0005] The present invention adopts the following technical solution: This invention provides a signal simulator for a nuclear power plant loose component monitoring system, comprising: The system comprises a control module, a signal generation module, and a human-computer interaction module; the control module is connected to both the signal generation module and the human-computer interaction module. The human-computer interaction module is used to display the signal characteristics of the simulated impact signal to the user and generate user commands to be sent to the control module in response to the user's operation of adjusting the signal characteristics. The control module is used to receive user commands and determine the signal parameters of the simulated impact signal. The control signal generation module generates the simulated impact signal according to the signal parameters. The signal generation module includes a direct digital frequency synthesizer, a pulse forming network, a material feature filtering network, and a gain amplification circuit. A direct digital frequency synthesizer is used to generate a sinusoidal fundamental signal with frequencies corresponding to signal parameters. A pulse forming network is used to convert a sinusoidal fundamental signal into an impulse pulse of corresponding width based on the control of the control module. The material characteristic filtering network, including an analog switch and high-pass, band-pass, and low-pass filters of different frequencies, is used to shape the spectrum of the impact pulse by passing the filter corresponding to the material through the signal parameters based on the control of the analog switch by the control module. The gain amplifier circuit is used to adjust the frequency-shaping impulse pulse to the amplitude corresponding to the signal parameters to obtain the simulated impulse signal.

[0006] Optionally, the pulse forming network includes a MOS transistor and an RC network. The gate of the MOS transistor is connected to the control module, the source is grounded, and the drain is connected in parallel with the capacitor in the RC network. The control module is used to control the on and off states of the MOS transistor and adjust the RC network to convert the sinusoidal fundamental signal into an impulse pulse with a width corresponding to the signal parameters.

[0007] Optionally, when simulating the impact signal of a loose stainless steel part, the impact pulse is spectrally shaped by a high-pass filter with a cutoff frequency of 20kHz. When simulating the impact signal of a loose carbon steel component, the impact pulse is spectrally shaped by a second-order bandpass filter with a center frequency of 15kHz. When simulating the impact signal of a loose alloy component, the impact pulse is spectrally shaped by a second-order low-pass filter with a cutoff frequency of 10kHz.

[0008] Optionally, the control module pre-stores various combinations of signal parameters for impact signals; The control module is used to respond to the user's operation selection and control the signal generation module to generate the simulated impact signal according to the corresponding signal parameter combination.

[0009] Optionally, the control module is configured with a scanning mode; The control module is used to receive user instructions and determine the frequency start point, frequency end point and frequency scanning speed of the simulated impact signal. The control signal generation module generates the simulated impact signal once or in a loop according to the frequency start point, frequency end point and frequency scanning speed. The frequency start point ranges from 100Hz to 15kHz, the frequency end point ranges from 2kHz to 20kHz, and the frequency scanning speed ranges from 100Hz / s to 1kHz / s.

[0010] Optionally, the human-computer interaction module includes: a display screen, two rotary encoders and three buttons, all of which are connected to the control module. The display screen is used to show the frequency, amplitude, pulse width, and material type of the simulated impact signal in real time. The first rotary encoder is used for frequency adjustment and menu selection, and the second rotary encoder is used for amplitude adjustment and value modification. The three buttons are used for power control, mode switching, and confirmation functions, respectively. The mode switching includes switching between standard mode, manual mode, and scanning mode. The standard mode represents selecting one of the signal parameter combinations of multiple pre-stored impact signals for signal generation. The manual mode represents forming signal parameters and generating signals in response to the user's real-time numerical modification operations. The scanning mode represents generating signals in response to the user's real-time selected frequency start point, frequency end point, and frequency scanning speed.

[0011] Optionally, it may also include: an output interface module; The output interface module includes an optocoupler isolation circuit and a BNC interface. The input terminal of the optocoupler isolation circuit is connected to the output terminal of the signal generation module. After optocoupler isolation, the signal is output through the BNC interface. Optocoupler isolation circuits are used for electrical isolation between signal ground and output ground to suppress common-mode interference; The BNC interface is used for stable output of the simulated impact signal.

[0012] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects: This invention receives the signal parameters of the impact signal to be simulated by the signal simulator through a human-computer interaction module, and generates the signal through a signal generation module controlled by a controller. First, a sinusoidal fundamental signal with the frequency corresponding to the signal parameters is generated by a direct digital frequency synthesizer. Then, a pulse forming network converts the sinusoidal fundamental signal into an impact pulse with the width corresponding to the signal parameters. Next, a filter corresponding to the material of the loose component to be simulated performs spectral shaping on the impact pulse. Finally, a gain amplification circuit adjusts the spectral-shaped impact pulse to the amplitude corresponding to the signal parameters to obtain the simulated impact signal. This invention can simulate different signal characteristics of the impact signal generated by the impact of a loose component from multiple angles, improving the simulation accuracy of the impact signal of a loose component impact and better meeting the debugging and verification needs of loose component alarm algorithms. Attached Figure Description

[0013] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0014] Figure 1 This invention provides a schematic diagram of the structure of a signal simulator for a nuclear power plant loose component monitoring system; Figure 2 A schematic diagram of a signal simulator for loose components in a nuclear power plant, provided by the present invention; Figure 3A power module circuit diagram provided by the present invention; Figure 4 A circuit diagram of a core control module provided by the present invention; Figure 5a A schematic diagram of a direct digital frequency synthesizer and pulse forming network provided by the present invention; Figure 5b A schematic diagram of a material feature filtering network provided by the present invention; Figure 5c A schematic diagram of a gain amplifier circuit provided by the present invention; Figure 6 A circuit diagram of an output interface module provided by the present invention; Figure 7a A schematic diagram of a rotary encoder and a button provided by the present invention; Figure 7b This is a schematic diagram of a display screen provided by the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0016] Currently, loose component monitoring systems use mechanical methods (such as hammering or striking with steel balls) to generate impact signals and / or use general signal generators to generate standard vibration signals for debugging and calibration. Both methods have the following drawbacks: Mechanical method: It damages the primary circuit equipment and its exterior, and cannot be used under hot conditions; the quantitative accuracy is insufficient and cannot meet the calibration requirements.

[0017] Typical signal generators can only produce standard sine waves, and the frequency components of the signal generated each time are singular. They cannot simulate impact signal waves and cannot meet the debugging and verification requirements of loose part alarm algorithms.

[0018] Therefore, there is an urgent need for a signal simulator that can simulate the characteristics of impact signals in order to solve the above problems.

[0019] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the structure of a signal simulator for a nuclear power plant loose component monitoring system according to the present invention.

[0021] The signal simulator may include: a control module, a signal generation module, and a human-computer interaction module; the control module is connected to the signal generation module and the human-computer interaction module respectively.

[0022] The human-computer interaction module is used to display the signal characteristics of the simulated impact signal to the user and generate user commands to be sent to the control module in response to the user's operation of adjusting the signal characteristics.

[0023] The control module receives user commands and determines the signal parameters of the simulated impact signal. The control signal generation module generates the simulated impact signal based on the signal parameters.

[0024] The signal generation module includes a direct digital frequency synthesizer, a pulse forming network, a material feature filtering network, and a gain amplification circuit connected in sequence.

[0025] A direct digital frequency synthesizer is used to generate a sinusoidal fundamental signal with frequencies corresponding to signal parameters. A pulse forming network is used to convert a sinusoidal fundamental signal into an impulse pulse of corresponding width based on the control of the control module.

[0026] The material characteristic filtering network, including an analog switch and high-pass, band-pass, and low-pass filters of different frequencies, is used to shape the spectrum of the impact pulse by means of filters corresponding to the material through the control of the analog switch by the control module.

[0027] The gain amplifier circuit is used to adjust the frequency-shaping impulse pulse to the amplitude corresponding to the signal parameters to obtain the simulated impulse signal.

[0028] Furthermore, in one or more embodiments of the present invention, the signal simulator may also include a power supply module. Specifically, the power supply module may be powered by two 14500 lithium batteries connected in series (3.7V×2, 7.4V), with a capacity ≥1200mAh. It uses a TP4056 charging management chip to achieve safe charging, supports 5V / 1A charging, and has overcharge and over-discharge protection. A dual LDO structure supplies power to the digital circuit (3.3V) and analog circuit (5.0V) respectively, ensuring power stability and low noise characteristics. This module has a three-level power management function, which can dynamically adjust power consumption according to the operating status to extend the battery life (noise ≤10μVrms).

[0029] The control module can be based on an STM32L051 low-power MCU, paired with a 26MHz TCXO clock source (frequency stability ±1ppm), and is responsible for receiving user commands, calculating signal parameters, controlling the signal generation process, and implementing low-power management.

[0030] In one or more embodiments of the present invention, the control module can perform three-level power consumption management: Operating status (power consumption ≤ 160mA): All modules are activated.

[0031] Idle state (power consumption ≤80mA): The display brightness is reduced by 50%, and it will automatically enter idle state after 3 minutes of inactivity.

[0032] Sleep mode (power consumption ≤ 5mA): Only the real-time clock is retained, and it will automatically enter sleep mode after 10 minutes of inactivity.

[0033] Specifically, in one or more embodiments of the present invention, the direct digital frequency synthesizer may be an AD9833 DDS chip, used to generate a 100Hz~20kHz sine wave base signal under the control of an MCU, with a frequency adjustment step of 1Hz and an accuracy of ±50ppm.

[0034] The pulse forming network may include a 2N7002 high-speed MOSFET and an RC network. The gate of the MOSFET is connected to the control module, the source is grounded, and the drain and capacitors in the RC network are connected in parallel. The control module is used to control the on and off of the MOSFET and adjust the RC network to convert the sinusoidal basic signal into an impulse pulse with an adjustable width of 20~200μs.

[0035] The material characteristic filtering network can contain three sets of dedicated filters, which respectively simulate the spectral characteristics of stainless steel (20kHz high-pass), carbon steel (15kHz band-pass), and alloy (10kHz low-pass), and are switched by a 74HC4052 analog switch.

[0036] Specifically, in one or more embodiments of the present invention, when simulating the impact signal of a loose stainless steel component, the impact pulse can be spectrally shaped using a high-pass filter (1kΩ+8nF) with a cutoff frequency of 20kHz, and the signal attenuation above 30kHz is ≤1dB; when simulating the impact signal of a loose carbon steel component, the impact pulse can be spectrally shaped using a second-order bandpass filter with a center frequency of 15kHz and a bandwidth of 8kHz; when simulating the impact signal of a loose alloy component, the impact pulse can be spectrally shaped using a second-order low-pass filter (1kΩ+13.5nF) with a cutoff frequency of 10kHz, and the signal attenuation above 20kHz is ≥20dB.

[0037] The variable gain amplifier circuit may include an MCP4261 digital potentiometer (1024-level adjustment) and an OPA350 operational amplifier to adjust the signal amplitude to 0.1~10Vpp, with an adjustment step of 0.05V and a total harmonic distortion of <0.5%. The pulse forming network can also adjust the exponential decay time (100-1000μs) via the digital potentiometer.

[0038] In one or more embodiments of the present invention, the human-machine interaction module may include a 1.3-inch OLED display screen (128×64 resolution), two EC11 rotary encoders (with pressing function), and three touch buttons. The display screen is used to display the frequency, amplitude, pulse width, and material type of the simulated impact signal in real time, and may also display the battery status; the main encoder is used for frequency adjustment and menu selection, and the auxiliary encoder is used for amplitude adjustment and value modification; the three buttons respectively realize power control, mode switching, and confirmation functions.

[0039] The mode switching includes switching between standard mode, manual mode and scanning mode. The standard mode represents selecting one of the signal parameter combinations of a variety of pre-stored impact signals for signal generation. The manual mode represents forming signal parameters and generating signals in response to the user's real-time numerical modification operations. The scanning mode represents generating signals in response to the user's real-time selected frequency start point, frequency end point and frequency scanning speed.

[0040] In the standard mode, in one or more embodiments of the present invention, the control module may pre-store various combinations of signal parameters for impact signals. Based on this, the control module can be used to control the signal generation module to generate the simulated impact signal according to the corresponding combination of signal parameters, in response to the user's operation selection.

[0041] For scanning modes, the control module can be configured with scanning modes. Based on this, the control module can receive user commands and determine the frequency start point, frequency end point, and frequency scanning speed of the simulated impact signal. The control signal generation module generates the simulated impact signal in one cycle or loop based on the frequency start point, frequency end point, and frequency scanning speed. The frequency start point ranges from 100Hz to 15kHz, the frequency end point ranges from 2kHz to 20kHz, and the frequency scanning speed ranges from 100Hz / s to 1kHz / s.

[0042] The signal simulator may also include an output interface module, which comprises an optocoupler isolation circuit and a BNC interface. The input of the optocoupler isolation circuit is connected to the output of the signal generation module. After optocoupler isolation, the signal is output through the BNC interface. The optocoupler isolation circuit provides electrical isolation between the signal ground and the output ground, with an isolation voltage of 2500Vrms, suppressing common-mode interference. The BNC interface is compatible with standard test cables and is used for stable output of the simulated impulse signal.

[0043] When performing signal simulation based on the above signal simulator, users can follow these steps: S1: When the user starts the device with the power button, the device enters the standard mode by default, and the display shows the current parameters.

[0044] S2: Users can switch working modes (standard mode / manual mode / scanning mode) using the mode key, and set specific parameters using the encoder and buttons. Standard mode: Directly select one of the preset parameter combinations.

[0045] For example, five preset parameter combinations can be set: Mode 1: 15kHz frequency, 50μs pulse width, stainless steel material, 3Vpp amplitude, τ=300μs.

[0046] Mode 2: 20kHz frequency, 30μs pulse width, carbon steel material, 1Vpp amplitude, τ=200μs.

[0047] Mode 3: 10kHz frequency, 60μs pulse width, alloy material, 5Vpp amplitude, τ=400μs.

[0048] Mode 4: 5kHz frequency, 40μs pulse width, stainless steel material, 2Vpp amplitude, τ=250μs.

[0049] The attenuation curve of the pulse forming network conforms to the formula: V(t) = V0 × e (-t / τ) , where τ is the decay time constant.

[0050] Mode 5: Customizable storage parameters, supporting the saving and recall of 3 sets of user preset values.

[0051] Manual mode: Set the frequency (100Hz-20kHz), amplitude (0.1-10Vpp), pulse width (20-200μs), and material type (stainless steel / carbon steel / alloy) respectively. Scanning mode: Set the starting frequency (100Hz-15kHz), ending frequency (2kHz-20kHz), and scan speed (100Hz / s-1kHz / s). S3: After receiving the parameters, the core control module calculates the DDS frequency control word, pulse width timer parameters, filter switching instructions, and gain control values. S4: The signal generation module performs the following operations: The DDS chip generates a sinusoidal signal of the corresponding frequency according to the control word. The pulse forming network converts the sinusoidal signal into an impulse pulse of a set width. The analog switch selects the corresponding filter according to the material type to perform spectrum shaping on the pulse signal. The variable gain amplifier adjusts the signal amplitude to the set value.

[0052] S5: The output interface module performs optical isolation on the signal, switches the output impedance according to the settings, and finally outputs the analog signal through the BNC interface.

[0053] S6: The device monitors the battery voltage in real time and flashes a warning on the display when the battery level is less than 20%. It automatically enters a low-power state when there is no operation and quickly wakes up after receiving an operation command.

[0054] The present invention has the following beneficial effects: Highly matched simulation: Specifically covers the frequency range of 100Hz-20kHz, highly matching the actual impact signal characteristics of loose parts in nuclear power plants, and can highly simulate real metal impact.

[0055] High-precision simulation: frequency accuracy ±50ppm, amplitude adjustment accuracy ±3%, material feature matching degree >92%, ensuring the accuracy of LPMS calibration.

[0056] Excellent portability: It measures only 122mm×82mm×31mm and weighs ≤200g (including battery), supporting 12 hours of continuous operation and meeting the needs of on-site mobile debugging.

[0057] Easy to operate: Parameters can be quickly adjusted through dual coding and buttons, and core parameters are displayed on a single page, reducing the complexity of operation.

[0058] The following is a specific application embodiment based on the present invention. Figure 2 This is a schematic diagram of a signal simulator for loose components in a nuclear power plant according to the present invention, as shown below. Figure 2 As shown, the nuclear power plant loose component signal simulator of this embodiment includes a power supply module 1, a core control module 2, a signal generation module 3, a human-machine interaction module 4, and an output interface module 5.

[0059] The specific circuit of power module 1 is as follows: Figure 3 As shown: Two 14500 lithium batteries (BAT1, BAT2) are connected in series to provide a 7.4V voltage, which is connected to the circuit through a reverse connection protection diode D1 (SS14); the TP4056 charging chip U1 is responsible for charging management, and charging is carried out through the Micro-USB interface J1 with a charging current set to 500mA; two LDO chips U2 (TPS73633) and U3 (TPS7A4700) output 3.3V and 5.0V respectively to power the digital and analog circuits; C1-C6 are filter capacitors, of which C1 and C2 are 10μF ceramic capacitors, C3 and C4 are 47μF electrolytic capacitors, and C5 and C6 are 100nF ceramic capacitors to ensure that the output voltage ripple is <1mV; C7 and C8 are noise reduction capacitors to further reduce the power supply noise of the system.

[0060] The specific circuit of core control module 2 is as follows: Figure 4As shown: The STM32L051F8P6 microcontroller U4 is the core, with an external 26MHz TCXO clock source Y1 (SG-8002CA), which is stably oscillating through R4 (22Ω) and C9-C10 (10pF); the SPI interface (PA5-PA7) of U4 is connected to the DDS chip and digital potentiometer, the I2C interface (PB6-PB7) is connected to the OLED display, and the GPIO interface (PA0-PA1, PB3-PB4, PA3, PA4, PB0) is connected to the encoder and buttons; C11-C13 and C15 are power supply filter capacitors, R2 is the reset resistor, and C16 is the power-on reset capacitor.

[0061] The specific circuit of signal generation module 3 is as follows: Figure 5a As shown in ~c. Figure 5a This is a schematic diagram of a direct digital frequency synthesizer and pulse forming network according to the present invention. Figure 5b This is a schematic diagram of a material feature filtering network in this invention. Figure 5c This is a schematic diagram of a gain amplifier circuit in this invention. The AD9833 DDS chip U5 receives control commands from U4 via the SPI interface and generates a 100Hz-20kHz sine wave signal, which is output from the VOUT pin. The pulse forming network includes a MOSFET Q1 (2N7002), a resistor R29 (1kΩ), and a capacitor C24 (100pF). The gate of Q1 is controlled by PB1 of U4, achieving a pulse width adjustment of 20-200μs. The 74HC4052 analog switch U6 selects three sets of filters (stainless steel / carbon steel / alloy), wherein:

[0062] Stainless steel mode: 20kHz high-pass filter consisting of R28 (1kΩ) and C21 (8nF).

[0063] Carbon steel mode: A bandpass filter with a center frequency of 15kHz and a bandwidth of 8kHz is composed of R30 (1.2kΩ), R31 (1kΩ), C25 (13.5nF), and C26 (5.6nF).

[0064] Alloy mode: A 10kHz low-pass filter consisting of R32 (1.15kΩ) and C28 (13.5nF).

[0065] The MCP4261 digital potentiometer U7 and the OPA350 operational amplifier U8 form a variable gain amplifier. The SPI interface of U7 is controlled by U4 (PA8~PA11) to achieve an amplitude adjustment of 0.1-10Vpp.

[0066] The specific circuit of output interface module 5 is as follows: Figure 6As shown: TLP2361 optocoupler U9 provides signal isolation, with the input side connected to the output of the signal generation module (U9: SIG signal), and pin 5 of U9 on the output side drives the subsequent circuit; G6K relay K1 is controlled by PA2 of U4, switching between 50Ω resistor R8 (0.1% accuracy) and 1MΩ resistor R9 (1% accuracy) to achieve impedance matching; J2 is a miniature BNC interface that outputs analog signals; TVS diode D2 (SMBJ6.5A) provides overvoltage protection.

[0067] The specific circuit of the human-computer interaction module 4 is as follows: Figure 7a As shown in ~b. Figure 7a This is a schematic diagram of a rotary encoder and a button according to the present invention. Figure 7b This is a schematic diagram of a display screen according to the present invention. The human-computer interaction module 4 includes: a 1.3-inch OLED display screen (driven by SSD1306), connected to U4 via an I2C interface; two EC11 rotary encoders (with push switches), respectively connected to PA0-PA1 (main encoder) and PB3-PB4 (auxiliary encoder) of U4; and three tactile buttons (power button, mode button, and confirmation button), respectively connected to PA3, PA44, and PB0 of U4.

[0068] The workflow of this embodiment is as follows: Press the power button to power on and initialize the device. It will enter the standard mode by default, and the display will show the parameters of mode 1 (15kHz, 50μs, stainless steel, 3Vpp).

[0069] Rotate the main encoder to switch to standard mode (1-5), press the confirmation button to take effect; short press the mode button to switch to manual mode, adjust the frequency (rotate) and pulse width (long press + rotate) through the main encoder, and adjust the amplitude (rotate) and material type (long press + rotate) through the auxiliary encoder; long press the mode button to switch to scanning mode, set the start frequency (100Hz-15kHz), end frequency (2kHz-20kHz) and scanning speed.

[0070] After the parameters are set, U4 calculates the frequency control word of AD9833 (formula: control word = frequency × 2). 28 (12.5MHz) is sent to U5 via SPI; at the same time, the conduction time (pulse width) of Q1 is set, U6 is controlled to switch the corresponding filter, and the resistance value of U7 is adjusted to set the gain.

[0071] The signal is isolated by U9 and impedance matched by K1, and then output through J2.

[0072] The device monitors the battery voltage in real time (sampled by the U4's ADC). The display screen flashes when the battery level is less than 20%. It enters idle state (brightness decreases) after 3 minutes of inactivity and sleep state (only the clock is retained) after 10 minutes. The rotary encoder wakes it up.

[0073] This invention receives the signal parameters of the impact signal to be simulated by the signal simulator through a human-computer interaction module, and generates the signal through a signal generation module controlled by a controller. First, a sinusoidal fundamental signal with the frequency corresponding to the signal parameters is generated by a direct digital frequency synthesizer. Then, a pulse forming network converts the sinusoidal fundamental signal into an impact pulse with the width corresponding to the signal parameters. Next, a filter corresponding to the material of the loose component to be simulated performs spectral shaping on the impact pulse. Finally, a gain amplification circuit adjusts the spectral-shaped impact pulse to the amplitude corresponding to the signal parameters to obtain the simulated impact signal. This invention can simulate different signal characteristics of the impact signal generated by the impact of a loose component from multiple angles, improving the simulation accuracy of the impact signal of a loose component impact and better meeting the debugging and verification needs of loose component alarm algorithms.

[0074] It should also be noted that the terms "comprising," "including," or any other variations thereof in this invention are intended to cover non-exclusive inclusion, that is, in addition to the elements listed in this invention, other elements not expressly listed may also be included.

[0075] The various embodiments in this invention are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0076] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A signal simulator for a nuclear power plant loose component monitoring system, characterized in that, include: The system comprises a control module, a signal generation module, and a human-computer interaction module; the control module is connected to both the signal generation module and the human-computer interaction module. The human-computer interaction module is used to display the signal characteristics of the simulated impact signal to the user and generate user commands to be sent to the control module in response to the user's operation of adjusting the signal characteristics. The control module is used to receive user commands and determine the signal parameters of the simulated impact signal. The control signal generation module generates the simulated impact signal according to the signal parameters. The signal generation module includes a direct digital frequency synthesizer, a pulse forming network, a material feature filtering network, and a gain amplification circuit connected in sequence. A direct digital frequency synthesizer is used to generate a sinusoidal fundamental signal with frequencies corresponding to signal parameters. A pulse forming network is used to convert a sinusoidal fundamental signal into an impulse pulse of corresponding width based on the control of the control module. The material characteristic filtering network, including an analog switch and high-pass, band-pass, and low-pass filters of different frequencies, is used to shape the spectrum of the impact pulse by passing the filter corresponding to the material through the signal parameters based on the control of the analog switch by the control module. The gain amplifier circuit is used to adjust the frequency-shaping impulse pulse to the amplitude corresponding to the signal parameters to obtain the simulated impulse signal.

2. The signal simulator for a nuclear power plant loose component monitoring system as described in claim 1, characterized in that, The pulse forming network includes a MOS transistor and an RC network. The gate of the MOS transistor is connected to the control module, the source is grounded, and the drain and capacitor in the RC network are connected in parallel. The control module is used to control the on and off states of the MOS transistor and adjust the RC network to convert the sinusoidal basic signal into an impulse pulse with a width corresponding to the signal parameters.

3. The signal simulator for a nuclear power plant loose component monitoring system as described in claim 1, characterized in that, When simulating the impact signal of a loose stainless steel component, the impact pulse is spectrally shaped by a high-pass filter with a cutoff frequency of 20kHz. When simulating the impact signal of a loose carbon steel component, the impact pulse is spectrally shaped by a second-order bandpass filter with a center frequency of 15kHz. When simulating the impact signal of a loose alloy component, the impact pulse is spectrally shaped by a second-order low-pass filter with a cutoff frequency of 10kHz.

4. The signal simulator for a nuclear power plant loose component monitoring system as described in claim 1, characterized in that, The control module pre-stores various combinations of signal parameters for impact signals; The control module is used to respond to the user's operation selection and control the signal generation module to generate the simulated impact signal according to the corresponding signal parameter combination.

5. The signal simulator for a nuclear power plant loose component monitoring system as described in claim 1, characterized in that, The control module is configured with a scanning mode; The control module is used to receive user instructions and determine the frequency start point, frequency end point and frequency scanning speed of the simulated impact signal. The control signal generation module generates the simulated impact signal once or in a loop according to the frequency start point, frequency end point and frequency scanning speed. The frequency start point ranges from 100Hz to 15kHz, the frequency end point ranges from 2kHz to 20kHz, and the frequency scanning speed ranges from 100Hz / s to 1kHz / s.

6. The signal simulator for a nuclear power plant loose component monitoring system as described in claim 1, characterized in that, The human-computer interaction module includes: a display screen, two rotary encoders and three buttons, all of which are connected to the control module. The display screen is used to show the frequency, amplitude, pulse width, and material type of the simulated impact signal in real time. The first rotary encoder is used for frequency adjustment and menu selection, and the second rotary encoder is used for amplitude adjustment and value modification. The three buttons are used for power control, mode switching, and confirmation functions, respectively. The mode switching includes switching between standard mode, manual mode, and scanning mode. The standard mode represents selecting one of the signal parameter combinations of multiple pre-stored impact signals for signal generation. The manual mode represents forming signal parameters and generating signals in response to the user's real-time numerical modification operations. The scanning mode represents generating signals in response to the user's real-time selected frequency start point, frequency end point, and frequency scanning speed.

7. The signal simulator for a nuclear power plant loose component monitoring system as described in claim 1, characterized in that, Also includes: Output interface module; The output interface module includes an optocoupler isolation circuit and a BNC interface. The input terminal of the optocoupler isolation circuit is connected to the output terminal of the signal generation module. After optocoupler isolation, the signal is output through the BNC interface. Optocoupler isolation circuits are used for electrical isolation between signal ground and output ground to suppress common-mode interference; The BNC interface is used for stable output of the simulated impact signal.

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