Magnetic field sensor based on amorphous wire giant magnetoimpedance effect

Abstract

The application provides a magnetic field sensor based on amorphous wire giant magnetoimpedance effect, and relates to the technical field of magnetic field testing.The magnetic field sensor comprises a sensitive element module, an excitation module, a signal processing module and an anti-interference module; the sensitive element module adopts CoFeSiB amorphous wire as core sensitive material, and the periphery of the amorphous wire is uniformly wound with enameled wire to form an inductor coil; the giant magnetoimpedance effect of the amorphous wire is converted into a voltage signal through the inductor coil; the excitation module is used for generating and outputting a high-frequency alternating excitation signal and loading the excitation signal to both ends of the inductor coil, so that the amorphous wire generates impedance change related to the magnetic field strength to be measured under the action of the high-frequency current. Through the modular design and multi-technology cooperation of the amorphous wire giant magnetoimpedance effect, the Wheatstone bridge anti-interference, the temperature compensation algorithm, the multi-layer dense winding and the impedance matching process, the performance bottleneck of traditional magnetic field sensors in sensitivity, anti-interference, temperature drift control and signal transmission efficiency is broken through, and high-precision and high-reliability wide-temperature-range magnetic field detection is realized.

Description

Technical Field

[0001] This invention relates to the field of magnetic field testing technology, and in particular to a magnetic field sensor based on the amorphous filament giant magnetoresistance effect. Background Technology

[0002] As a key device for converting magnetic fields and their changes into electrical signals, magnetic field sensors have broad application prospects in fields such as biomedicine, industrial inspection, and geological exploration. In nature, the distribution of the geomagnetic field, weak magnetic signals in living organisms (such as magnetocardiography and magnetoencephalography), and leakage magnetic field phenomena in industrial equipment all require the sensing and quantification of high-precision magnetic field sensors.

[0003] Traditional magnetic field sensors (such as Hall sensors and fluxgate sensors) have revealed significant limitations in practical applications: Hall sensors are limited by material properties and are insufficient to respond to weak magnetic fields at the nanotesla (nT) level, and are easily affected by temperature drift; although fluxgate sensors have high sensitivity, their complex structure and high power consumption make it difficult to meet the requirements of miniaturization and low power consumption scenarios.

[0004] Amorphous filaments exhibit potential in weak magnetic field detection due to their excellent magnetoresistance effect; however, efficiently converting their impedance changes into electrical signals and suppressing environmental noise and temperature drift remain technical challenges. Therefore, this invention provides a magnetic field sensor based on the giant magnetoresistance effect of amorphous filaments through modular design and hardware algorithm collaboration to address these technical problems. Summary of the Invention

[0005] This invention provides a magnetic field sensor based on the amorphous filament giant magnetoresistance effect to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides a magnetic field sensor based on the amorphous filament giant magnetoresistance effect, comprising a sensing element module, an excitation module, a signal processing module, and an anti-interference module;

[0007] The sensitive element module uses CoFeSiB amorphous wire as the core sensitive material. Enamelled wire is uniformly wound around the amorphous wire to form an inductor coil. The giant magnetoresistance effect of the amorphous wire is converted into a voltage signal through the inductor coil.

[0008] The excitation module is used to generate and output a high-frequency alternating excitation signal. The excitation signal is applied to both ends of the inductor coil, causing the amorphous wire to generate an impedance change related to the strength of the magnetic field to be measured under the action of high-frequency current.

[0009] The signal processing module is used to filter, amplify, and perform analog-to-digital conversion on the voltage signal of the inductor coil.

[0010] The anti-interference module uses a differential bridge structure to suppress common-mode noise.

[0011] Preferably, the excitation module includes a signal generator, a power amplifier, and a field-effect transistor switching circuit;

[0012] The signal generator is used to generate high-frequency alternating signals with specific frequencies and phases;

[0013] The power amplifier is used to amplify the amplitude of the signal output by the signal generator.

[0014] The field-effect transistor switching circuit is used to control the on / off state of the excitation signal and apply it to both ends of the inductor coil.

[0015] Preferably, the signal processing module includes a low-pass filter circuit, an amplifier circuit, and an analog-to-digital converter circuit;

[0016] The low-pass filter circuit is used to filter out high-frequency noise in the voltage signal and retain the low-frequency modulation signal that reflects the change in the magnetic field.

[0017] The amplifier circuit is used to amplify the filtered signal to improve the signal-to-noise ratio.

[0018] The analog-to-digital converter circuit is used to convert the amplified analog signal into a digital signal.

[0019] Preferably, the anti-interference module adopts a bridge structure with four inductor coils connected in series:

[0020] Divide the four inductors into two groups, with two coils in the same axial direction. As a group, two coils on the other axis For the other group, the number of turns, size, and magnetic circuit distribution of the two groups of coils are completely symmetrical, forming a Wheatstone bridge structure. Furthermore, common-mode noise interference is canceled out using the differential principle, specifically:

[0021] When the external common-mode noise magnetic field causes the impedance of each coil group to change At that time, control the output voltage of the bridge. The expression for the bridge output voltage is: ,in, This represents the excitation voltage applied to both ends of the bridge diagonal. This represents the initial impedance of the coil. The change in coil impedance caused by external common-mode noise magnetic field.

[0022] Preferably, the present invention further includes a temperature compensation module, which monitors the temperature in real time by integrating a thermistor and employs a linear compensation algorithm, including the following steps:

[0023] Temperature is sensed in real time by a thermistor integrated inside the sensor; the thermistor resistance value... With temperature T ,in For temperature The resistance value at that time, where B is the material constant of the thermistor;

[0024] Based on the linear relationship between temperature and sensor output deviation, the formula is used. Calculate the compensation voltage Where k is the temperature coefficient, This is a reference temperature value.

[0025] The calculated compensation voltage Compared with the sensor's original output voltage The calculation is performed to obtain the compensated output voltage. The calculation formula is: .

[0026] Preferably, the amorphous wire is annealed, and the annealing method includes conventional annealing, Joule heating annealing, stress annealing or magnetic field annealing.

[0027] Preferably, the process by which the inductor coil converts the amorphous wire giant magnetoresistance effect into a voltage signal includes:

[0028] A high-frequency alternating signal is applied to an inductor coil, causing amorphous wires to exhibit a skin effect. The formula for the skin depth is: ,in For amorphous filament resistivity, is the permeability of the amorphous wire, and f is the excitation frequency;

[0029] Utilizing the inductive reactance characteristics of an inductor coil, the impedance change of the amorphous wire is... Converted into the voltage change across the coil The formula is ,in This is the effective value of the excitation current. For the excitation voltage amplitude, The initial impedance of the amorphous wire is given.

[0030] Preferably, the inductor coil adopts a multi-layer close-wound process, with an insulating film between the layers, and an impedance matching network is integrated at both ends of the coil;

[0031] The impedance matching network consists of adjustable capacitors and resistors. By adjusting the parameters of the matching network, the coil impedance is matched with the output impedance of the excitation module.

[0032] Using a network analyzer to measure the impedance of an inductor coil and the output impedance of the excitation module According to the matching formula Calculate and adjust the values ​​of the adjustable capacitor and resistor to achieve impedance matching between them;

[0033] During the matching process, the total impedance of the inductor is changed by an adjustable capacitor C and a resistor R, where the inductor reactance... ,according to and ,satisfy and Impedance matching is achieved, where w is the angular frequency of the excitation signal and L is the inductance. This is the distributed capacitance.

[0034] Preferably, the temperature coefficient k is determined through the following experiments:

[0035] The difference between the sensor output voltage at different temperatures and the output voltage at a reference temperature is obtained. A linear relationship between temperature and output voltage deviation is fitted, and the slope of this linear relationship is the temperature coefficient k. Within the temperature range [Tmin, Tmax], the compensated sensor output error does not exceed ± , This is the set temperature error threshold.

[0036] Compared with related technologies, the magnetic field sensor based on the amorphous filament giant magnetoresistance effect provided by this invention has the following beneficial effects:

[0037] 1. This invention utilizes the giant magnetoresistance effect of CoFeSiB amorphous wire, combined with the skin effect generated by high-frequency excitation, to convert weak magnetic field changes into significant impedance changes, which are then efficiently converted into voltage signals by an inductor coil. With the help of filtering, amplification, and analog-to-digital conversion of the signal processing module, the accurate detection of nanotesla-level weak magnetic fields can be achieved.

[0038] 2. This invention employs an anti-interference module with a Wheatstone bridge structure. Through the differential principle of symmetrical inductors, impedance changes caused by common-mode noise are mutually canceled in the bridge output, effectively suppressing environmental electromagnetic interference, ensuring the purity of the detection signal, and improving reliability in complex electromagnetic environments.

[0039] 3. This invention solves the problem of decreased accuracy caused by temperature fluctuations in traditional sensors by setting up a temperature compensation module, integrating a thermistor to monitor temperature in real time, and combining it with a linear compensation algorithm to calculate and correct temperature drift, thus broadening the adaptability of application environments.

[0040] 4. The inductor coil of this invention adopts a multi-layer dense winding process and is equipped with an insulating film, which improves the inductance while ensuring the insulation performance. Combined with the adjustable impedance matching network integrated at both ends, the energy transmission of the excitation signal is optimized through the conjugate matching principle, reducing reflection loss.

[0041] In summary, this invention overcomes the performance bottlenecks of traditional magnetic field sensors in terms of sensitivity, anti-interference, temperature drift control, and signal transmission efficiency through modular design and multi-technology synergy, using amorphous wire giant magnetoresistance effect, Wheatstone bridge anti-interference, temperature compensation algorithm, multi-layer dense winding and impedance matching process. This enables high-precision and high-reliability wide-temperature-range magnetic field detection. Attached Figure Description

[0042] Figure 1 The schematic diagram of the magnetic field sensor based on the amorphous wire giant magnetoresistance effect provided by the present invention. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some 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.

[0044] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “group,” “class,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0045] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0046] Please refer to the following: Figure 1 A magnetic field sensor based on the amorphous filament giant magnetoresistance effect includes a sensing element module, an excitation module, a signal processing module, and an anti-interference module.

[0047] The sensing element module uses CoFeSiB amorphous wire as the core sensing material. Enamelled wire is uniformly wound around the amorphous wire to form an inductor coil. The giant magnetoresistance effect of the amorphous wire is converted into a voltage signal through the inductor coil.

[0048] The excitation module is used to generate and output a high-frequency alternating excitation signal. The excitation signal is applied to both ends of the inductor coil, causing the amorphous wire to generate an impedance change related to the strength of the magnetic field to be measured under the action of high-frequency current.

[0049] The signal processing module is used to filter, amplify, and perform analog-to-digital conversion on the voltage signal of the inductor coil to extract the effective signal;

[0050] The anti-interference module uses a differential bridge structure to suppress common-mode noise, ensuring the accuracy and reliability of the detection signal.

[0051] Specifically, the excitation module includes a signal generator, a power amplifier, and a field-effect transistor switching circuit;

[0052] A signal generator is used to generate high-frequency alternating signals with specific frequencies and phases;

[0053] Power amplifiers are used to amplify the amplitude of the signal output from a signal generator;

[0054] The field-effect transistor switching circuit is used to control the on / off state of the excitation signal and apply it to both ends of the inductor coil.

[0055] It should be noted that the excitation module achieves high-frequency excitation of the inductor coil through the coordinated action of a signal generator, a power amplifier, and a field-effect transistor switching circuit: the signal generator provides a high-frequency alternating signal with a specific frequency and phase as the excitation source; the power amplifier amplifies the amplitude of the signal to ensure that the excitation energy is sufficient to drive the amorphous wire to generate a significant giant magnetoresistance effect; the field-effect transistor switching circuit is responsible for controlling the on and off of the excitation signal and accurately loading the amplified signal onto both ends of the inductor coil, so that the amorphous wire generates an impedance change related to the strength of the magnetic field to be measured under the action of high-frequency current, providing an effective input for subsequent signal processing.

[0056] Specifically, the signal processing module includes a low-pass filter circuit, an amplifier circuit, and an analog-to-digital converter circuit;

[0057] Low-pass filter circuits are used to filter out high-frequency noise in voltage signals and retain low-frequency modulation signals that reflect changes in the magnetic field;

[0058] Amplifier circuits are used to amplify the filtered signal to improve the signal-to-noise ratio.

[0059] Analog-to-digital converters are used to convert amplified analog signals into digital signals.

[0060] It should be noted that the signal processing module achieves signal optimization through a three-stage circuit: the low-pass filter circuit utilizes the frequency selectivity of the RC network to filter out high-frequency noise (such as a 60kHz carrier wave) from the excitation signal, retaining only low-frequency signals (typically <1kHz) related to magnetic field changes; the amplifier circuit adopts an instrumentation amplifier structure, which amplifies the weak filtered signal by adjusting the feedback resistor ratio, thereby increasing the signal strength to match the subsequent analog-to-digital conversion requirements; the analog-to-digital conversion circuit (such as a 16-bit ADC) converts the amplified analog signal into a digital signal with high quantization accuracy, facilitating digital filtering, algorithm calculation, and other processing by the embedded system or host computer, ultimately achieving accurate quantization of the magnetic field strength.

[0061] Specifically, the anti-interference module adopts a bridge structure with four inductor coils connected in series:

[0062] Divide the four inductors into two groups, with two coils in the same axial direction. As a group, two coils on the other axis For the other group, the number of turns, size, and magnetic circuit distribution of the two groups of coils are completely symmetrical, forming a Wheatstone bridge structure. Furthermore, common-mode noise interference is canceled out using the differential principle, specifically:

[0063] When the external common-mode noise magnetic field causes the impedance of each coil group to change At that time, control the output voltage of the bridge. The expression for the bridge output voltage is: ,in, This represents the excitation voltage applied to both ends of the bridge diagonal. This represents the initial impedance of the coil. The change in coil impedance caused by external common-mode noise magnetic field.

[0064] It should be noted that in scenarios where a Wheatstone bridge structure is used to cancel common-mode noise interference, the expression for the bridge output voltage is used to calculate the bridge's output voltage. When an external common-mode noise magnetic field acts uniformly on the coils in the bridge, due to the symmetrical structural design of the bridge, the coils at symmetrical positions (such as...) ) will produce the same impedance change (both become The output voltage of the bridge can be calculated using this formula. A value of 0 indicates that the common-mode noise signals cancel each other out in this symmetrical bridge structure. This achieves common-mode noise elimination at the hardware level, ensuring that the bridge output signal does not contain common-mode noise components, thereby improving the accuracy and reliability of the magnetic field sensor in detecting the magnetic field signal under test.

[0065] Specifically, the present invention also includes a temperature compensation module, which monitors the temperature in real time by integrating a thermistor and employs a linear compensation algorithm, including the following steps:

[0066] Temperature is sensed in real time by a thermistor integrated inside the sensor; the thermistor resistance value... With temperature T ,in For temperature The resistance value at that time, where B is the material constant of the thermistor;

[0067] Based on the linear relationship between temperature and sensor output deviation, the formula is used. Calculate the compensation voltage Where k is the temperature coefficient, This is a reference temperature value.

[0068] The calculated compensation voltage Compared with the sensor's original output voltage The calculation is performed to obtain the compensated output voltage. The calculation formula is: .

[0069] It should be noted that the temperature compensation module achieves temperature drift correction through a combination of hardware and algorithms: it utilizes an integrated thermistor to monitor the ambient temperature in real time, based on the non-linear relationship between its resistance and temperature (…). ) to deduce the current temperature value; through a linear compensation algorithm ( ) Calculate the output deviation compensation amount caused by temperature changes, where the temperature coefficient k is determined experimentally; finally, calculate the compensation voltage with the original output voltage. This eliminates the influence of temperature on sensor accuracy and ensures the stability of detection results in a wide temperature range.

[0070] Specifically, amorphous wires undergo annealing treatment, including conventional annealing, Joule heating annealing, stress annealing, or magnetic field annealing.

[0071] Specifically, the process by which an inductor coil converts the amorphous wire giant magnetoresistance effect into a voltage signal includes:

[0072] A high-frequency alternating signal is applied to an inductor coil, causing amorphous wires to exhibit a skin effect. The formula for the skin depth is: ,in For amorphous wire resistivity, The permeability of the amorphous wire and the excitation frequency (f) together determine the penetration depth of the current on the surface of the amorphous wire. The external magnetic field, by changing... This affects the skin depth and current distribution, which in turn leads to changes in the amorphous wire impedance Z.

[0073] Utilizing the inductive reactance characteristics of an inductor coil, the impedance change of the amorphous wire is... Converted into the voltage change across the coil The formula is ,in This is the effective value of the excitation current. For the excitation voltage amplitude, The initial impedance of the amorphous wire, and the change in impedance of the amorphous wire. The impedance change is determined by the difference between the voltage signals across the inductor at different acquisition times. This formula establishes a quantitative relationship between the electrical signal and the impedance change. The impedance change of the amorphous wire is determined by the difference between the voltage signals across the inductor at different acquisition times, thereby accurately converting the impedance effect corresponding to the magnetic field change into a measurable voltage signal.

[0074] Specifically, the inductor coil adopts a multi-layer close-wound process, with an insulating film between the layers, and an impedance matching network is integrated at both ends of the coil;

[0075] It should be noted that the coil inductance L is related to the permeability of the amorphous wire. They are directly proportional, and the formula is: ,in Let A be the permeability of free space, A be the cross-sectional area of ​​the coil, and l be the length of the coil.

[0076] The impedance matching network consists of adjustable capacitors and resistors. By adjusting the parameters of the matching network, the coil impedance is matched with the output impedance of the excitation module.

[0077] Using a network analyzer to measure the impedance of an inductor coil and the output impedance of the excitation module According to the principle of conjugate matching, its matching formula is... Calculate and adjust the values ​​of the adjustable capacitor and resistor to achieve impedance matching between them;

[0078] During the matching process, the total impedance of the inductor is changed by an adjustable capacitor C and a resistor R, where the inductor reactance... ,according to and ,satisfy and Impedance matching is achieved, where w is the angular frequency of the excitation signal and L is the coil inductance. The distributed capacitance is used; by changing the adjustable capacitor C and the resistor R, the total impedance is adjusted so that the excitation signal energy is transmitted to the coil to the maximum extent and the reflection loss is reduced.

[0079] Specifically, the temperature coefficient k was determined through the following experiments:

[0080] The difference between the sensor output voltage at different temperatures and the output voltage at a reference temperature is obtained. A linear relationship between temperature and output voltage deviation is fitted, and the slope of this linear relationship is the temperature coefficient k. Within the temperature range [Tmin, Tmax], the compensated sensor output error does not exceed ± , The set temperature error threshold is used to accurately correct temperature drift and ensure the measurement accuracy of the sensor in a wide temperature range.

[0081] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0082] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A magnetic field sensor based on the amorphous filament giant magnetoresistance effect, characterized in that, It includes a sensitive element module, an excitation module, a signal processing module, and an anti-interference module; The sensing element module uses CoFeSiB amorphous wire as the core sensing material. Enamelled wire is uniformly wound around the amorphous wire to form an inductor coil. The giant magnetoresistance effect of the amorphous wire is converted into a voltage signal through the inductor coil. The conversion process includes: A high-frequency alternating signal is applied to an inductor coil, causing amorphous wires to exhibit a skin effect. The formula for the skin depth is: ,in For amorphous filament resistivity, is the permeability of the amorphous wire, and f is the excitation frequency; Utilizing the inductive reactance characteristics of an inductor coil, the impedance change of the amorphous wire is... Converted into the voltage change across the coil The formula is ,in This is the effective value of the excitation current. For the excitation voltage amplitude, The initial impedance of the amorphous wire; The excitation module is used to generate and output a high-frequency alternating excitation signal. The excitation signal is applied to both ends of the inductor coil, causing the amorphous wire to generate an impedance change related to the strength of the magnetic field to be measured under the action of high-frequency current. The signal processing module is used to filter, amplify, and perform analog-to-digital conversion on the voltage signal of the inductor coil. The anti-interference module adopts a differential bridge structure to suppress common-mode noise, specifically using a bridge structure with four inductor coils connected in series: Divide the four inductors into two groups, with two coils in the same axial direction. As a group, two coils on the other axis For the other group, the number of turns, size, and magnetic circuit distribution of the two groups of coils are completely symmetrical, forming a Wheatstone bridge structure. Furthermore, common-mode noise interference is canceled out using the differential principle, specifically: When the external common-mode noise magnetic field causes the impedance of each coil group to change At that time, control the output voltage of the bridge. The expression for the bridge output voltage is: ,in, This represents the excitation voltage applied to both ends of the bridge diagonal. This represents the initial impedance of the coil. The change in coil impedance caused by external common-mode noise magnetic field; It also includes a temperature compensation module, which monitors the temperature in real time through an integrated thermistor and employs a linear compensation algorithm, including the following steps: Temperature is sensed in real time by a thermistor integrated inside the sensor; the thermistor resistance value... With temperature T, it satisfies ,in For temperature The resistance value at that time, where B is the material constant of the thermistor; Based on the linear relationship between temperature and sensor output deviation, the formula is used. Calculate the compensation voltage Where k is the temperature coefficient, This is a reference temperature value; The calculated compensation voltage Compared with the sensor's original output voltage The calculation is performed to obtain the compensated output voltage. The calculation formula is: ; The inductor coil adopts a multi-layer close-wound process, with an insulating film between the layers, and an impedance matching network is integrated at both ends of the coil. The impedance matching network consists of adjustable capacitors and resistors. By adjusting the parameters of the matching network, the coil impedance is matched with the output impedance of the excitation module. Using a network analyzer to measure the impedance of an inductor coil and the output impedance of the excitation module According to the matching formula Calculate and adjust the values ​​of the adjustable capacitor and resistor to achieve impedance matching between them; During the matching process, the total impedance of the inductor is changed by adjusting the capacitor C and the resistor R, where the inductor reactance... ,according to and ,satisfy and Impedance matching is achieved, where w is the angular frequency of the excitation signal and L is the inductance. This is the distributed capacitance.

2. The magnetic field sensor based on the amorphous filament giant magnetoresistance effect according to claim 1, characterized in that, The excitation module includes a signal generator, a power amplifier, and a field-effect transistor switching circuit; The signal generator is used to generate high-frequency alternating signals with specific frequencies and phases; The power amplifier is used to amplify the amplitude of the signal output by the signal generator. The field-effect transistor switching circuit is used to control the on / off state of the excitation signal and apply it to both ends of the inductor coil.

3. The magnetic field sensor based on the amorphous filament giant magnetoresistance effect according to claim 1, characterized in that, The signal processing module includes a low-pass filter circuit, an amplifier circuit, and an analog-to-digital converter circuit; The low-pass filter circuit is used to filter out high-frequency noise in the voltage signal and retain the low-frequency modulation signal that reflects the change in the magnetic field. The amplifier circuit is used to amplify the filtered signal to improve the signal-to-noise ratio. The analog-to-digital converter circuit is used to convert the amplified analog signal into a digital signal.

4. The magnetic field sensor based on the amorphous filament giant magnetoresistance effect according to claim 1, characterized in that, The amorphous wire undergoes annealing treatment, including conventional annealing, Joule heating annealing, stress annealing, or magnetic field annealing.

5. The magnetic field sensor based on the amorphous filament giant magnetoresistance effect according to claim 1, characterized in that, The temperature coefficient k was determined through the following experiments: The difference between the sensor output voltage at different temperatures and the output voltage at a reference temperature is obtained. A linear relationship between temperature and output voltage deviation is fitted, and the slope of this linear relationship is the temperature coefficient k. Within the temperature range [Tmin, Tmax], the compensated sensor output error does not exceed ± , This is the set temperature error threshold.

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