A temperature self-adaptive based eddy current signal dynamic compensation system

Abstract

This application provides a temperature-adaptive eddy current signal dynamic compensation system, including a high-temperature eddy current sensor, a high-temperature temperature sensor, a signal processing module, a data storage module, and a control module. The temperature sensor is used to collect temperature data of a high-temperature alloy sample in real time. The data storage module is used to store material property data of the high-temperature alloy sample. The control module is used to determine the optimal excitation frequency and driving voltage based on the temperature data and material property data. The signal processing module includes a DDS signal generator, a PID controller, and a PGA programmable gain amplifier, used to dynamically compensate the excitation signal and detection signal of the high-temperature eddy current sensor. This invention effectively stabilizes the detection sensitivity under high-temperature conditions, keeping the amplitude fluctuation of the temperature-compensated eddy current signal within 3%, and ensuring that the signal-to-noise amplitude is basically consistent with the initial state, thereby achieving accuracy and reliability of eddy current non-destructive testing under high-temperature conditions.

Description

Technical Field

[0001] This invention relates to the field of information technology, and in particular to a temperature-adaptive eddy current signal dynamic compensation system. Background Technology

[0002] Eddy current nondestructive testing (EDT) technology faces severe challenges in high-temperature environments. As ambient temperature rises, the conductivity and permeability of the tested material change significantly, leading to large fluctuations in the detection signal and severely impacting measurement accuracy and reliability. This problem is particularly prominent in harsh high-temperature environments such as nuclear power and aerospace. Traditional fixed-parameter testing methods cannot adapt to the dynamic changes in material properties, and the detection sensitivity fluctuates drastically with temperature. Maintaining the stability and accuracy of eddy current testing in high-temperature environments has become a pressing technical challenge. This involves several key factors: firstly, how to accurately acquire and characterize the changes in material properties with temperature; secondly, the performance of various components of the testing system (such as excitation coils and signal amplifiers) is also affected by high temperatures; and thirdly, how to quickly adjust the detection parameters based on real-time temperature to compensate for temperature effects. These factors are interrelated and mutually influential, constituting a complex systemic problem. Failure to effectively address this will severely restrict the application of eddy current EDT technology in high-temperature environments, affecting the safety and efficiency of industrial production. Summary of the Invention

[0003] To address one of the aforementioned technical problems, this invention provides an adaptive dynamic temperature field eddy current signal compensation system, comprising a high-temperature eddy current sensor, a high-temperature temperature sensor, a signal processing module, a data storage module, and a control module. The temperature sensor is used to acquire temperature data of a high-temperature alloy sample in real time. The data storage module is used to store material property data of the high-temperature alloy sample, including the mapping relationship between electrical conductivity and magnetic permeability as a function of temperature. The control module is used to determine the optimal excitation frequency and driving voltage based on the temperature data and material property data. The signal processing module includes a DDS signal generator, a PID controller, and a PGA programmable gain amplifier, used to dynamically compensate the excitation signal and detection signal of the high-temperature eddy current sensor according to the optimal excitation frequency and driving voltage.

[0004] Furthermore, the high-temperature sensor includes one of the following: thermocouple temperature sensor, thermistor temperature sensor, semiconductor temperature sensor, infrared temperature sensor, bimetallic rod sensor, and metal tube sensor.

[0005] Furthermore, the high-temperature sensor is a thermocouple temperature sensor.

[0006] Furthermore, the method of applying the above system for eddy current signal compensation mainly includes:

[0007] Acquire temperature and material property data of a high-temperature alloy specimen, wherein the material property data includes the mapping relationship between electrical conductivity and magnetic permeability as a function of temperature; determine the optimal excitation frequency and driving voltage at the current temperature based on the temperature and material property data, for dynamic compensation of the eddy current signal; adjust the excitation frequency of the eddy current sensor using a direct digital signal generator based on the optimal excitation frequency to compensate for the skin effect shift caused by changes in material conductivity under high-temperature conditions; adjust the driving voltage of the eddy current sensor using a PID control algorithm based on the driving voltage to counteract the temperature drift of the coil impedance; output the dynamically compensated eddy current detection signal.

[0008] Furthermore, the acquisition of temperature data of the high-temperature alloy test block includes: arranging a high-temperature eddy current sensor and a high-temperature temperature sensor on the high-temperature alloy test block; and collecting the temperature data of the high-temperature alloy test block in real time through the high-temperature temperature sensor.

[0009] Furthermore, the acquisition of material property data of the high-temperature alloy specimen includes: simulating the high-temperature alloy specimen using material simulation software to obtain curves showing the change of electrical conductivity and magnetic permeability with temperature; and storing the electrical conductivity curve and the magnetic permeability curve as a mapping relationship.

[0010] Furthermore, determining the optimal excitation frequency at the current temperature includes: setting a constant skin depth; querying the conductivity and permeability corresponding to the current temperature from the mapping relationship based on the temperature data; and calculating the optimal excitation frequency required to maintain the constant skin depth based on the constant skin depth, the conductivity and permeability corresponding to the current temperature.

[0011] Furthermore, determining the driving voltage includes: acquiring the change in coil impedance of the eddy current sensor under high temperature conditions; calculating the adjustment amount of the driving voltage using a PID control algorithm based on the change in coil impedance, wherein the input of the PID control algorithm is the change in coil impedance, and the output is the adjustment amount of the driving voltage; and adjusting the driving voltage applied to the eddy current sensor based on the adjustment amount of the driving voltage.

[0012] Furthermore, the step of adjusting the driving voltage of the eddy current sensor using a PID control algorithm based on the driving voltage further includes:

[0013] The signal-to-noise amplitude values ​​of the eddy current sensor signal at different temperatures are obtained in advance, and a mapping table between temperature and signal-to-noise amplitude is established. The mapping table records the optimal signal gain at each temperature.

[0014] Based on the current temperature, the mapping table is consulted to obtain the optimal signal gain corresponding to the current temperature, and the driving voltage amplitude after adjustment by the programmable amplifier is calculated.

[0015] Furthermore, if there are defects on the high-temperature alloy test block, the eddy current sensor will scan along a direction perpendicular to the defects.

[0016] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0017] This invention discloses an adaptive dynamic temperature field eddy current signal compensation system. The system acquires the conductivity and permeability curves of the test block as a function of temperature, and combines this with real-time ambient temperature data to dynamically adjust the excitation frequency and driving voltage of the eddy current sensor. Specifically, the invention queries a material property database based on the current temperature to calculate the optimal excitation frequency and adjusts it using a DDS signal generator; a PID control algorithm is used to adjust the driving voltage in real time to compensate for coil impedance changes caused by high temperatures. Through these compensation measures, the invention effectively stabilizes the detection sensitivity under high-temperature conditions, keeping the amplitude fluctuation of the temperature-compensated eddy current signal within 3%, and maintaining a signal-to-noise ratio essentially consistent with the initial state, thereby achieving accuracy and reliability in eddy current non-destructive testing under high-temperature conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the working principle of an adaptive dynamic temperature field eddy current signal compensation system according to the present invention.

[0019] Figure 2 This is a flowchart of an adaptive dynamic temperature field eddy current signal compensation method according to the present invention. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1

[0022] like Figure 1As shown, this embodiment provides an adaptive dynamic temperature field eddy current signal compensation system, which specifically includes a data acquisition module 1. The data acquisition module can be a high-temperature temperature sensor, such as a thermocouple temperature sensor, a thermistor temperature sensor, a resistance temperature sensor, a semiconductor temperature sensor, an infrared temperature sensor, a bimetallic rod sensor, and a metal tube sensor, etc. Among them, the thermocouple temperature sensor and the infrared temperature sensor can measure high temperatures up to 2300℃. Thermocouple temperature sensors have relatively high accuracy. The data storage module 3 is used to store the material property data of the high-temperature alloy sample, including the mapping relationship between electrical conductivity and magnetic permeability as a function of temperature. The data acquisition module transmits temperature data to the control module 2, and the data storage module transmits material property data to the control module 2 simultaneously. Based on temperature data, control module 2 determines the optimal excitation frequency using skin depth and the conductivity and permeability corresponding to the current temperature obtained through querying. This optimal excitation frequency is used to dynamically compensate for the eddy current sensor signal. Based on material property data, it acquires the impedance change of the eddy current sensor coil. Signal processing module 4 calculates the driving voltage adjustment based on this impedance change using a PID control algorithm. This driving voltage is used to dynamically compensate for the eddy current sensor signal. Simultaneously, after acquiring the temperature data of the high-temperature alloy sample, signal processing module 4 queries a temperature-signal-noise amplitude mapping table to determine the optimal signal gain corresponding to the current temperature. It then calculates the driving voltage amplitude after adjustment by a programmable amplifier, which is then transmitted to control module 2. This system features high detection sensitivity, stability, reliability, and accurate output of eddy current signals under variable temperature fields.

[0023] Example 2

[0024] like Figure 2 Based on the system of Embodiment 1, this embodiment provides an adaptive dynamic temperature field eddy current signal compensation method, which may specifically include:

[0025] S101. Obtain the material conductivity-temperature curve σ(T) and magnetic permeability-temperature curve μ(T) of the test block, and deploy the high-temperature eddy current sensor and temperature sensor on the test block to obtain the ambient temperature data T in real time.

[0026] Using JMatpro material simulation software, a material category matching the test block was selected, and the proportion of each element in the test block material was input to obtain simulation parameters. Based on the simulation parameters, JMatpro software was run to generate curves showing the change of electrical conductivity σ(T) and magnetic permeability μ(T) of the test block with temperature. The curve data of electrical conductivity σ(T) and magnetic permeability μ(T) were stored in a database to form a mapping relationship between temperature and electrical conductivity and temperature and magnetic permeability. A high-temperature eddy current sensor and a high-temperature temperature sensor were deployed on the high-temperature alloy test block, and the sensor data acquisition function was activated. The ambient temperature data T was collected in real time by the high-temperature temperature sensor and transmitted to the data processing module. Based on the collected temperature data T, the database was queried to obtain the corresponding electrical conductivity σ(T) and magnetic permeability μ(T) values. If the temperature data T exceeded the pre-stored range in the database, JMatpro software was called to perform real-time simulation to supplement and generate the missing electrical conductivity σ(T) and magnetic permeability μ(T) data. The acquired conductivity σ(T) and permeability μ(T) values ​​are transmitted to the dynamic parameter adjustment module for subsequent signal processing. The dynamic parameter adjustment module adjusts the driving voltage of the eddy current sensor in real time to compensate for coil impedance changes caused by high-temperature environments and maintain signal output stability.

[0027] For example, using JMatpro material simulation software, a material category matching the test block is selected, such as a nickel-based superalloy. The percentage of each element in the test block material is input, for example, nickel 60%, chromium 20%, titanium 10%, and the remainder being trace elements, to obtain simulation parameters. Based on the simulation parameters, JMatpro software is run, setting the temperature range to 20℃ to 1000℃ with a step size of 10℃, to generate curves showing the change of conductivity σ(T) and permeability μ(T) of the test block with temperature. For example, the conductivity at 500℃ is 1.2 × 10⁻⁶. 6 The conductivity (S / m) and permeability (μ) are 1.05. The curves of conductivity σ(T) and permeability μ(T) are stored in a database to form temperature-conductivity and temperature-permeability mapping relationships. For example, a temperature of 500℃ corresponds to a conductivity of 1.2 × 10⁻⁶. 6 S / m and permeability 1.05. A high-temperature eddy current sensor and a high-temperature temperature sensor are deployed on the high-temperature alloy specimen. The sensor data acquisition function is activated, and the sampling frequency is set to 100Hz. Ambient temperature data T is collected in real time by the high-temperature temperature sensor; for example, if the current temperature is 600℃, the data is transmitted to the data processing module. Based on the collected temperature data T, the database is queried to obtain the corresponding conductivity σ(T) and permeability μ(T) values; for example, the conductivity at 600℃ is 1.1 × 10⁻⁵. 6The conductivity σ(T) and permeability μ(T) are 1.03. If the temperature data T exceeds the pre-stored range in the database, for example, if the temperature is 1050℃, JMatpro software will be called for real-time simulation to supplement and generate the missing conductivity σ(T) and permeability μ(T) data. For example, the conductivity at 1050℃ is 0.9 × 10⁻⁶. 6 The conductivity (S / m) and permeability (μ / T) are 0.98. The acquired conductivity (σ(T) and permeability (μ(T)) values ​​are transmitted to the dynamic parameter adjustment module for subsequent signal processing. The dynamic parameter adjustment module adjusts the driving voltage of the eddy current sensor in real time, for example, adjusting the driving voltage from 5V to 6V, to compensate for coil impedance changes caused by high-temperature environments and maintain signal output stability.

[0028] S102. Based on the current temperature T, query the material property database to obtain the corresponding electrical conductivity σ(T) and magnetic permeability μ(T). Combined with the constant skin depth δ0, calculate the optimal excitation frequency f after compensation, and dynamically adjust the excitation frequency of the eddy current sensor through the DDS signal generator.

[0029] The ambient temperature T is collected in real time by a temperature monitoring module to obtain temperature data. Based on the current temperature T, a pre-stored material property database is consulted to match the corresponding conductivity σ(T) and permeability μ(T). Using an initial skin depth δ0 as a constant value, and combining σ(T) and μ(T), the optimal excitation frequency f at the current temperature is calculated using the skin depth formula. If the calculated optimal excitation frequency f deviates from the original optimal excitation frequency δ0, a DDS signal generator is triggered for frequency adjustment. The DDS signal generator, based on digital frequency synthesis technology, generates a sine wave signal corresponding to the optimal excitation frequency f. A PID controller monitors the probe coil impedance change in real time and calculates the compensation drive voltage value. The PID controller outputs the adjusted drive voltage, which is applied to the eddy current sensor probe coil. A PGA programmable gain amplifier is used, and the signal amplification factor is automatically adjusted according to the pre-calibrated gain parameter mapping relationship. The excitation signal, after frequency, voltage, and gain adjustment, is applied to the eddy current sensor to complete the signal compensation process.

[0030] For example, the temperature monitoring module collects the current ambient temperature T in real time, such as 150℃. Based on the temperature of 150℃, it queries the pre-stored material property database and matches the corresponding conductivity σ(T) as 1.5×10⁻⁶. 6 S / m, permeability μ(T) is 1.2×10 -6H / m. Using an initial skin depth δ0 of 0.5 mm as a constant value, and combining σ(T) and μ(T), the skin depth formula δ=√(1 / (πfμσ)) is applied to calculate the optimal excitation frequency f at the current temperature as 200 kHz. If the calculated optimal excitation frequency f deviates from the original optimal excitation frequency δ0 of 180 kHz, the DDS signal generator is triggered for frequency adjustment. The DDS signal generator, based on digital frequency synthesis technology, generates a sine wave signal corresponding to the optimal excitation frequency f of 200 kHz, with a frequency resolution of 1 Hz. A PID controller monitors the probe coil impedance change in real time; for example, if the impedance changes from 50Ω to 55Ω, the compensation drive voltage is calculated to be 12V. The PID controller outputs the adjusted drive voltage of 12V, which is applied to the eddy current sensor probe coil. A PGA programmable gain amplifier is used, and the signal amplification factor is automatically adjusted according to the pre-calibrated gain parameter mapping relationship, for example, if the gain is adjusted from 20dB to 22dB. An excitation signal with a frequency adjusted to 200kHz, a voltage adjusted to 12V, and a gain adjusted to 22dB is applied to the eddy current sensor to complete the signal compensation process.

[0031] S103. The PID control algorithm is used to adjust the driving voltage in real time to compensate for the coil impedance change ΔZ caused by high temperature, and to ensure the stability of the excitation magnetic field strength. The proportional, integral and derivative coefficients are dynamically optimized according to the temperature T.

[0032] The system acquires ambient temperature data, collecting the current ambient temperature T in real time via a temperature monitoring module. It calculates the impedance change ΔZ using the formula ΔZ = α * (T - 25) based on temperature T and the impedance change temperature coefficient α. It determines the proportional coefficient Kp using linear interpolation based on a preset mapping relationship between temperature T and the proportional coefficient. It also determines the integral coefficient Ki using polynomial fitting based on a preset mapping relationship between temperature T and the integral coefficient. Finally, it determines the derivative coefficient Kd using exponential function fitting based on a preset mapping relationship between temperature T and the derivative coefficient. The system calculates the PID control output using the PID control algorithm formula based on ΔZ, Kp, Ki, and Kd. It adjusts the drive voltage in real time using a voltage adjustment module based on the PID control output. Finally, it monitors the magnetic field strength by collecting the current excitation magnetic field strength data using a magnetic field strength sensor. Optimize PID parameters. If the magnetic field strength deviates from the preset range, recalculate Kp, Ki, and Kd based on the deviation value and update the PID control algorithm parameters.

[0033] For example, the ambient temperature T is collected in real time by a temperature monitoring module, such as 150℃ in a high-temperature environment. Based on the temperature T and the temperature coefficient of impedance change α (assuming α is 0.02Ω / ℃), the impedance change is calculated using the formula ΔZ = α * (T - 25), resulting in ΔZ = 0.02 * (150 - 25) = 2.5Ω. Based on the mapping relationship between temperature T and a preset proportional coefficient, for example, Kp is 1.0 at 25℃ and 1.5 at 200℃, the Kp value at the current temperature is calculated using linear interpolation, resulting in Kp = 1.0 + (1.5 - 1.0) * (150 - 25) / (200 - 25) = 1.36. Based on the mapping relationship between temperature T and preset integral coefficients, for example, Ki is 0.01 at 25℃ and Ki is 0.03 at 200℃, the Ki value at the current temperature is calculated using a polynomial fitting method, resulting in Ki = 0.01 + 0.02 * (150 / 200)^2 = 0.021. Based on the mapping relationship between temperature T and preset differential coefficients, for example, Kd is 0.05 at 25℃ and Kd is 0.1 at 200℃, the Kd value at the current temperature is calculated using an exponential function fitting method, resulting in Kd = 0.05 * exp(0.01 * (150 - 25)) = 0.067. Based on ΔZ, Kp, Ki, and Kd, the current control output value is calculated using the PID control algorithm formula. For example, the output value = Kp*ΔZ + Ki*∫ΔZ dt + Kd*dΔZ / dt = 1.36*2.5 + 0.021*15 + 0.067*0.1 = 3.4 + 0.315 + 0.0067 = 3.7217. Based on the PID control output value, the driving voltage of the eddy current sensor is adjusted in real time via the voltage regulation module, for example, adjusting the driving voltage to 3.72V. The current excitation magnetic field strength data is collected via a magnetic field strength sensor, for example, measuring a magnetic field strength of 50mT. If the magnetic field strength deviates from the preset range (assuming the preset range is 48mT to 52mT), then Kp, Ki, and Kd are recalculated based on the deviation value. For example, when the deviation is -2mT, Kp = 1.36 + 0.1 * (-2) = 1.16, Ki = 0.021 + 0.001 * (-2) = 0.019, Kd = 0.067 + 0.005 * (-2) = 0.057, and the PID control algorithm parameters are updated.

[0034] S104. Perform defect location analysis on the temperature-compensated eddy current signal to obtain the probe position-signal amplitude curve at different temperatures. The signal amplitude fluctuation after compensation is controlled within 3%, and the signal-noise amplitude is basically consistent with the initial state.

[0035] The current temperature value is obtained based on the ambient temperature data collected by the temperature monitoring module. A DDS signal generator is used to dynamically calculate the optimal excitation frequency based on the current temperature value to compensate for the skin effect shift caused by changes in conductivity. A PID controller optimizes the drive voltage in real time according to temperature fluctuations to compensate for changes in probe coil impedance under high-temperature conditions. A PGA programmable gain amplifier adaptively adjusts the signal amplification gain according to a pre-calibrated gain parameter mapping relationship. The eddy current probe scans perpendicular to the defect direction, collecting compensated eddy current signal data. The amplitude of the compensated eddy current signal is extracted to generate a probe position-signal amplitude curve. The fluctuation range of the compensated signal amplitude is analyzed to determine whether it is controlled within 3% of the original signal amplitude. The signal-to-noise ratio (SNR) amplitude of the compensated signal is calculated and compared with the SNR amplitude in the initial state. Based on the probe position-signal amplitude curve, the defect center location and the trend of signal amplitude change are determined.

[0036] For example, the temperature monitoring module collects ambient temperature data to obtain the current temperature value, such as real-time monitoring within the range of 25℃ to 205℃. The DDS signal generator dynamically calculates the optimal excitation frequency based on the current temperature value using digital frequency synthesis technology, for example, adjusting the excitation frequency from 1MHz to 1.2MHz in a high-temperature environment to compensate for the skin effect shift caused by changes in conductivity. The PID controller optimizes the drive voltage in real-time according to temperature fluctuations, dynamically adjusting the drive voltage output using a proportional coefficient Kp = 0.5, an integral coefficient Ki = 0.2, and a derivative coefficient Kd = 0.1 to compensate for changes in probe coil impedance, for example, adjusting the drive voltage from 5V to 5.5V. The PGA programmable gain amplifier adaptively adjusts the signal amplification gain according to a pre-calibrated gain parameter mapping relationship, for example, adjusting the gain from 20dB to 22dB to ensure signal-to-noise amplitude stability. The eddy current probe scans perpendicular to the defect direction, collecting compensated eddy current signal data, for example, collecting signal amplitude within the range of -5mm to 5mm from the probe position. The compensated eddy current signal amplitude is extracted to generate a probe position-signal amplitude curve. For example, the defect signal amplitude reaches its peak at position 0, while the signal amplitude is lower in the ranges of -5mm to -2mm and 2mm to 5mm. The fluctuation range of the compensated signal amplitude is analyzed to determine whether it is controlled within 3% of the original signal amplitude; for example, the fluctuation range of the compensated signal amplitude is ±2.8%. The signal-to-noise ratio (SNR) amplitude of the compensated signal is calculated and compared with the SNR amplitude in the initial state; for example, the SNR amplitude of the compensated signal is 50dB, which is basically consistent with the initial state of 51dB. Based on the probe position-signal amplitude curve, the defect center position and the trend of signal amplitude change are determined. For example, the defect signal amplitude is the largest at position 0, indicating that the defect center position is accurate.

[0037] Adjusting the driving voltage of the eddy current sensor according to the driving voltage using a PID control algorithm further includes:

[0038] The signal-to-noise amplitude values ​​of the eddy current sensor signal at different temperatures are obtained in advance, and a mapping table between temperature and signal-to-noise amplitude is established. The mapping table records the optimal signal gain at each temperature.

[0039] Based on the current temperature, the mapping table is consulted to obtain the optimal signal gain corresponding to the current temperature, and the driving voltage amplitude after adjustment by the programmable amplifier is calculated.

[0040] In actual measurement, if the induced driving voltage is too small to output a signal, it is necessary to amplify the driving voltage to obtain the amplified driving voltage amplitude. For example, based on the ambient temperature data collected by the temperature monitoring module, the current temperature value T is obtained. Using a pre-calibrated temperature-signal-noise amplitude mapping table, the optimal signal gain G corresponding to the current temperature T is looked up. The optimal signal gain G is written to the PGA's gain control register through the programmable gain amplifier (PGA) interface. Upon receiving the gain value G written to the gain control register, the PGA adjusts the gain factor of its internal amplification circuit. The eddy current sensor collects the raw signal and inputs it to the PGA for amplification. The PGA amplifies the input signal according to the set gain value G to obtain the amplified output signal. Based on the amplified output signal, the signal-to-noise amplitude (SNR) of the current signal is calculated. If the calculated SNR deviates from the target SNR, the gain value G in the temperature-signal-noise amplitude mapping table is adjusted according to the deviation. Update the temperature-signal-noise amplitude mapping table, re-associate the adjusted gain value G with the current temperature T, and complete the dynamic optimization of the mapping table.

[0041] For example, the temperature monitoring module collects ambient temperature data through a high-precision temperature sensor at a sampling frequency of 10Hz, obtaining the current temperature value T as 25.3℃. A pre-calibrated temperature-signal-noise amplitude mapping table is used, which stores the optimal signal gain G corresponding to the temperature range of -20℃ to 200℃ at 5℃ intervals. A linear interpolation algorithm is used to find the optimal signal gain G corresponding to the current temperature T, which is 12.5dB. The obtained optimal signal gain G is written to the PGA's gain control register via the SPI interface of the programmable gain amplifier (PGA). The register address is 0x03, and the data length is 16 bits. Upon receiving the gain value G written to the gain control register, the PGA adjusts the gain factor of its internal amplification circuit to 10^(G / 20), which is approximately 10^(12.5 / 20) ≈ 4.47 times. An eddy current sensor collects the raw signal at a sampling frequency of 1MHz, with a signal amplitude of 10mV, and inputs the signal to the PGA for amplification. The PGA amplifies the input signal according to the set gain value G. The input signal amplitude is 10mV, and the amplified output signal amplitude is approximately 44.7mV (10mV × 4.47). Based on the amplified output signal, the signal-to-noise ratio (SNR) is calculated using a Fast Fourier Transform (FFT) algorithm. The signal power is 1mW, the noise power is 0.01mW, and the SNR is 10 × log10(1 / 0.01) = 20dB. If the calculated SNR deviates from the target SNR of 25dB, the gain value G in the temperature-SNR mapping table is adjusted by 5dB, resulting in a new gain value G of 12.5 + 5 = 17.5dB. The temperature-SNR mapping table is then updated, re-associating the adjusted gain value G = 17.5dB with the current temperature T = 25.3℃, completing the dynamic optimization of the mapping table.

[0042] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A temperature-adaptive eddy current signal dynamic compensation system, characterized in that, The system includes a high-temperature eddy current sensor, a high-temperature temperature sensor, a signal processing module, a data storage module, and a control module. The temperature sensor is used to acquire temperature data of the high-temperature alloy sample in real time. The data storage module is used to store material property data of the high-temperature alloy sample, including the mapping relationship between electrical conductivity and magnetic permeability as a function of temperature. The control module is used to determine the optimal excitation frequency and driving voltage based on the temperature data and material property data. The signal processing module includes a DDS signal generator, a PID controller, and a PGA programmable gain amplifier, used to dynamically compensate the excitation signal and detection signal of the high-temperature eddy current sensor according to the optimal excitation frequency and driving voltage. The method for applying the system to dynamically compensate for eddy current signals includes: acquiring temperature data and material property data of a high-temperature alloy specimen, wherein the material property data includes the mapping relationship between electrical conductivity and magnetic permeability as a function of temperature; determining the optimal excitation frequency, driving voltage, and signal gain at the current temperature based on the temperature data and material property data, for dynamically compensating for eddy current signals; adjusting the excitation frequency of the eddy current sensor using a direct digital signal generator based on the optimal excitation frequency to compensate for the skin effect shift caused by changes in material conductivity under high-temperature conditions; and adjusting the driving voltage of the eddy current sensor using a PID control algorithm based on the driving voltage to counteract the temperature drift of the coil impedance. Output the dynamically compensated eddy current detection signal; The step of acquiring temperature data of the high-temperature alloy test block includes: arranging a high-temperature eddy current sensor and a high-temperature temperature sensor on the high-temperature alloy test block; and collecting temperature data of the high-temperature alloy test block in real time through the high-temperature temperature sensor. The process of obtaining material property data of the high-temperature alloy specimen includes: simulating the high-temperature alloy specimen using material simulation software to obtain curves of electrical conductivity and magnetic permeability changing with temperature; and storing the electrical conductivity and magnetic permeability curves as a mapping relationship. Determining the optimal excitation frequency at the current temperature includes: setting a constant skin depth; querying the conductivity and permeability corresponding to the current temperature from the mapping relationship based on the temperature data; and calculating the optimal excitation frequency required to maintain the constant skin depth based on the constant skin depth, the conductivity and permeability corresponding to the current temperature. Determining the driving voltage includes: acquiring the change in coil impedance of the eddy current sensor under high temperature conditions; and calculating the adjustment amount of the driving voltage using a PID control algorithm based on the change in coil impedance, wherein the input of the PID control algorithm is the change in coil impedance, and the output is the adjustment amount of the driving voltage. Output value = ,in This is the proportionality coefficient. The change in impedance. The integral coefficient is... The differential coefficient is used to adjust the driving voltage applied to the eddy current sensor according to the adjustment amount of the driving voltage. The step of adjusting the driving voltage of the eddy current sensor according to the driving voltage using a PID control algorithm further includes: pre-acquiring the signal-to-noise amplitude of the eddy current sensor signal at different temperatures, establishing a mapping table between temperature and signal-to-noise amplitude, wherein the mapping table records the optimal signal gain at each temperature; querying the mapping table according to the current temperature to obtain the optimal signal gain corresponding to the current temperature, and calculating the driving voltage amplitude after adjustment by the programmable amplifier.

2. The system according to claim 1, characterized in that: The high-temperature temperature sensor includes one of the following: thermocouple temperature sensor, thermistor temperature sensor, semiconductor temperature sensor, infrared temperature sensor, bimetallic rod and metal tube sensor.

3. The system according to claim 2, characterized in that: The high-temperature sensor is a thermocouple temperature sensor.

4. The system according to claim 1, characterized in that, The high-temperature alloy test block has defects, and the eddy current sensor scans along a direction perpendicular to the defects.

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