Current real-time measurement method and device based on tunnel magnetoresistive sensor and medium

Abstract

The invention discloses a current real-time measurement method and device based on tunnel magnetoresistive sensors and a medium, and belongs to the field of non-contact current sensing, and the method comprises the following steps: at least three tunnel magnetoresistive sensors are linearly arranged along the sensitivity direction of the tunnel magnetoresistive sensors to form a tunnel magnetoresistive sensor linear array; the sensor is used for collecting magnetic field intensity vectors excited by to-be-measured current; the method comprises the following steps: acquiring magnetic field intensity signals through an embedded processing unit, performing Gaussian blur processing, eliminating interference signals in an initial transient process, identifying effective wave crest positions in a stable section, performing average processing on the magnetic field intensity signals at the effective wave crest positions to obtain Hpeakavg, substituting the magnetic field intensity signals into a current solution equation, and calculating the current of the stable section according to the Hpeakavg. And calculating current intensity I through a Newton iteration method, and substituting Hpeakavg and I into a transmission coefficient K to simplify calculation. The device comprises a tunnel magnetoresistive sensor array module and an embedded processing unit, and real-time current magnitude and frequency measurement is completed in a microcontroller with limited computing resources.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of non-contact current sensing, and particularly relates to a current real-time measurement method, device and medium based on a tunnel magnetoresistance sensor. BACKGROUND

[0002] Current detection technology plays a crucial role in power systems, industrial automation, new energy, electric vehicles and other fields, and its precision directly affects the development of a series of fields such as electric energy metering, equipment protection, intelligent control. Traditional contact current sensors, such as shunts and current transformers, have problems such as large size, the need for contact installation, etc., so non-contact current sensors, such as Hall sensors, anisotropic magnetoresistance (AMR) sensors, giant magnetoresistance (GMR) sensors and tunnel magnetoresistance (TMR) sensors, have gradually become a research hotspot.

[0003] Compared with traditional non-contact current sensors, TMR as the third generation of magnetoresistance has advantages such as high sensitivity, low power consumption and high precision, and is widely used in the automotive, industrial and consumer electronics industries. TMR sensors include magnetic core TMR sensors, non-magnetic core TMR sensors and linear array TMR sensors. The magnetic core TMR sensor uses a high magnetic permeability magnetic core to concentrate the magnetic field, achieving accurate measurement, but has disadvantages such as large size, high cost and magnetic saturation. The non-magnetic core TMR sensor usually has a ring structure, which eliminates the magnetic core and coil, and has smaller size and weight, and is easier to integrate, but has high requirements for the position of the wire and the ring array, and the measured wire should pass vertically through the center of the ring array. A large measurement error will be caused if the position is offset. In addition, the non-magnetic core TMR sensor has weak anti-interference ability and is easily affected by the interference magnetic field in space. The linear array TMR sensor can meet the requirements of light weight, small size and high sensitivity, but still has bottlenecks in practicality and anti-interference. First, the transducer coefficient K depends on DC prediction to be applied in AC measurement, and cannot be used alone for AC current measurement, which is not practical. Secondly, it is easily affected by the space interference magnetic field, which will greatly affect the measurement of the sensor, reduce the measurement accuracy, or even cannot accurately measure. SUMMARY

[0004] To solve the problems of poor real-time performance and weak anti-interference ability of tunnel magnetoresistance (TMR) sensors, the present application provides a current real-time measurement method, device and medium based on a tunnel magnetoresistance sensor.

[0005] The technical solution of the present application is as follows: In a first aspect, the present application provides a current real-time measurement method based on a tunnel magnetoresistance sensor, comprising the following steps: The tunnel magnetoresistance sensor linear array is constructed by arranging at least three tunnel magnetoresistance sensors in a line along the sensitivity direction of the tunnel magnetoresistance sensors and arranging the tunnel magnetoresistance sensors at different spatial positions respectively, so as to collect magnetic field intensity signals excited by the current to be measured; The magnetic field signal intensity is collected by the embedded processing unit, the magnetic field intensity signal is subjected to Gaussian blur processing, the interference signal in the initial transient process is excluded, the effective wave peak position in the stable section is identified, the magnetic field intensity signals at not less than three effective wave peak positions with optimal signal-to-noise ratio are selected, the magnetic field intensity signals are subjected to average processing, and the average magnetic field intensity signal is obtained H peak_avg ; According to the positions, the sensitivity directions of the tunnel magnetoresistance sensors and the magnetic field intensity signals, a current solving equation is constructed, and the current intensity is calculated I ; A transfer coefficient function is constructed K According to the average magnetic field intensity signal H peak_avg and the current intensity I , the transfer coefficient K is obtained ; The transfer coefficient K and the average magnetic field intensity signal of the tunnel magnetoresistance sensor H peak_avg are used for real-time measurement of the current to be measured.

[0006] Further, the specific method of the Gaussian blur processing is as follows: A Gaussian kernel time constant is set, high-frequency noise higher than a cutoff frequency is suppressed under the corresponding cutoff frequency, a fundamental wave and at least three harmonics are retained, and the cutoff frequency is greater than or equal to 150 Hz; The signal sampling rate of the embedded processing unit is set f s According to the Nyquist sampling theorem, the signal sampling rate f s is set G [ i ] is dynamically generated, and G [ i ] is used for smoothing processing of the magnetic field intensity signal.

[0007] The time constant of the Gaussian kernel is set to σ = 1 ms, the corresponding medium frequency is: ; High-frequency noise higher than 159 Hz is suppressed, a fundamental wave and three harmonics are retained; According to the signal sampling rate , a discrete Gaussian function G is dynamically generatedi wherein, N is the number of discrete sampling points, i represents the discrete index of the element in the Gaussian array.

[0008] Further, the specific method of excluding interference signals in the initial transient process is to start searching for effective wave peaks and limiting the effective wave peaks to a preset number after a preset time; Then, the magnetic field intensity signals at the positions of the effective wave peaks are averaged to minimize the interference of spatial noise on the magnetic field intensity signals, i.e. wherein H peak is the magnetic field intensity signal at the effective wave peak, H peak_avg is the average value of the magnetic field intensity signal at the effective wave peak.

[0009] Further, according to the positions of the tunnel magnetoresistance sensors, the sensitivity directions and the magnetic field intensity signals, a current solving equation is constructed to calculate the current intensity I , specifically: The relationship between the positions of the tunnel magnetoresistance sensors and the sensitivity directions is as follows: wherein, is the sensitivity direction vector of the tunnel magnetoresistance sensor, P 1 is the first tunnel magnetoresistance sensor position, P 1=( x 1,0,0), P 2 is the second tunnel magnetoresistance sensor position, P 2=( x 2, y 2, z 2), m 1 is the distance between the tunnel magnetoresistance sensor at the P 1 position and the tunnel magnetoresistance sensor at the P 2 position; The position coordinates of the tunnel magnetoresistance sensors are in the positive direction of the z-axis in the direction of the current to be measured. The plane perpendicular to the z-axis is the x-y plane, the x-axis is in the x-y plane and along the arrangement direction of the linear array of the tunnel magnetoresistance sensors, and the y-axis is in the x-y plane and perpendicular to the arrangement direction of the linear array of the tunnel magnetoresistance sensors. The number of the tunnel magnetoresistance sensors is n, and n≥3. The magnetic field intensity vector of the nth tunnel magnetoresistance sensor is related to the position coordinates of the tunnel magnetoresistance sensors and the current intensity​​​​I The relationship is: ; in, x n Let x be the x-axis coordinate of the nth tunnel magnetoresistive sensor. y n Let y be the coordinate of the nth tunnel magnetoresistive sensor. The magnetic field strength signal sensed by the nth tunnel magnetoresistive sensor H n With sensitivity direction and magnetic field strength vector The relationship is: ; Construct the magnetic field strength signal of each tunnel magnetoresistive sensor H n With current intensity I The relationship is used as the equation for solving the current problem. The current intensity is obtained by solving the current equation using Newton's iteration method. I .

[0010] Furthermore, the number of the tunnel magnetoresistive sensors is j ,and j ≥3, the transmission coefficient K The definition of is: ; in, K The overall transmission coefficient of the linear array of tunnel magnetoresistive sensors is given. k j For the first j The transmission coefficient of a tunnel magnetoresistive sensor, H j For the first j The magnetic field strength signal sensed by a tunnel magnetoresistive sensor.

[0011] Furthermore, the number of the tunnel magnetoresistive sensors is j ,and j ≥3, transmission coefficient K The simplified formula for current calculation is: ; in, H n Let n be the magnetic field strength signal sensed by the nth tunnel magnetoresistive sensor. k n Let be the transmission coefficient of the nth tunnel magnetoresistive sensor. N This represents the number of magnetoresistive sensors used in the tunnel.

[0012] Further, the tunnel magnetoresistance sensor-based current real-time measurement method further comprises acquiring a frequency of the to-be-measured alternating current, specifically: After the effective peak positions in the stable section are identified, the frequency of the to-be-measured alternating current is calculated f , and the calculation formula is as follows: ; Among them, N peaks is the number of peaks, t last is the appearance time of the first effective peak, t first is the appearance time of the last effective peak.

[0013] In a second aspect, the present application provides a tunnel magnetoresistance sensor-based current real-time measurement device, comprising a tunnel magnetoresistance sensor array module and an embedded processing unit. The tunnel magnetoresistance sensor array module comprises at least three tunnel magnetoresistance sensors arranged linearly along the sensitivity direction and arranged at different spatial positions to collect the magnetic field strength signals excited by the to-be-measured conductor; The embedded processing unit comprises a signal acquisition and preprocessing module, a signal optimization and current calculation module, and a transfer coefficient calculation module, and can complete real-time current size and frequency measurement on a microcontroller with limited computing resources.

[0014] Further, the signal acquisition and preprocessing module is connected with the tunnel magnetoresistance sensor array module, acquires the magnetic field strength signals, performs Gaussian blur filtering on the magnetic field strength signals, identifies the effective peaks in the stable section, and calculates the frequency of the alternating current; The signal optimization and current calculation module selects the magnetic field strength signals at not less than three effective peaks with optimal signal-to-noise ratio for average processing, constructs a current solving equation, and optimizes the calculation by using the Newton iteration method; The transfer coefficient calculation module extracts the transfer coefficient from the magnetic field strength signals and the current K .

[0015] In a third aspect, the present application provides a computer readable storage medium, which stores computer executable instructions, and the computer executable instructions are used for executing the tunnel magnetoresistance sensor-based current real-time measurement method.

[0016] Compared with the prior art, the present application has the following advantages: (1) Gaussian blur processing effectively suppresses high-frequency noise, avoids peak misjudgment caused by noise interference, accurately obtains the magnetic field strength signal at the peak for subsequent calculation, and improves the calculation accuracy; (2) The selection of magnetic field intensity signal at the peak compensates for the interference of the interfering magnetic field in space on the TMR sensor, resulting in a higher signal-to-noise ratio. Furthermore, by detecting the stable segment, other interference problems can be eliminated to a greater extent. (3) The average value of the maximum magnetic field strength signal at multiple peaks is used for the transmission coefficient. K The calculation is performed, and the current value is solved by constructing a system of nonlinear equations and Newton's iteration method, so that the calculation results are more accurate; (4) It simplifies the iterative calculation in the current measurement process, significantly reduces the response time delay, and enables fast and accurate real-time measurement of AC current. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the linear array tunnel magnetoresistive sensor structure of the present invention; Figure 2 These are waveforms of the magnetic field strength signals detected by the four tunnel magnetoresistive sensors of this invention under noise-free conditions. Figure 3 This is a waveform diagram of the magnetic field strength signal detected by four tunnel magnetoresistive sensors under strong noise interference; Figure 4 It is tradition K Comparison chart of current measurement values ​​and current reference values ​​under the current calculation method; Figure 5 This is the optimal signal-to-noise ratio improved by the present invention. K A comparison chart of current measurement values ​​and current reference values ​​calculated using the value calculation method; Figure 6 This is a comparison of the magnetic field waveform detected by the tunnel magnetoresistive sensor under low signal-to-noise ratio conditions and the magnetic field waveform after Gaussian blurring. Figure 7 This is a comparison of the magnetic field waveform detected by the tunnel magnetoresistive sensor and the magnetic field waveform after Gaussian blurring at a signal-to-noise ratio of 72dB. Figure 8 This is a current detection result diagram based on the present invention. Detailed Implementation

[0018] To make the features and beneficial effects of the present invention more apparent and understandable, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Example 1 This embodiment provides a real-time current measurement method based on a tunnel magnetoresistive sensor, including the following steps: Construct a linear array of tunnel magnetoresistive sensors by arranging at least three tunnel magnetoresistive sensors in a straight line along their sensitivity direction and setting them at different spatial locations to collect the magnetic field strength signal excited by the current to be measured. Magnetic field strength signals are acquired through an embedded processing unit, and Gaussian blurring is applied to eliminate interference signals during the initial transient process. Effective peak positions within the stable segment are identified, and magnetic field strength signals at at least three effective peak positions with optimal signal-to-noise ratios are selected and averaged to obtain the final magnetic field strength signal. H peak_avg ; Based on the location and sensitivity direction of the tunnel magnetoresistive sensor Construct a current-solving equation based on the magnetic field strength signal to calculate the current intensity. I ; Constructing the transmission coefficient K The function is based on the magnetic field strength signal. H peak_avg and current intensity I Obtain the transmission coefficient K ; Through the transfer coefficient K Perform real-time current measurement.

[0020] like Figure 1 The diagram shown is a schematic of the linear array tunnel magnetoresistive sensor structure of this embodiment. The tunnel magnetoresistive current sensor includes... P One tunnel magnetoresistive sensor P Two tunnel magnetoresistive sensors P 3 tunnel magnetoresistive sensors and P Four tunnel magnetoresistive sensors; the conductor under test is located at z Axis, current direction z Positive half-axis; P Two tunnel magnetoresistive sensors to P The distance of one tunnel magnetoresistive sensor is m 1, P Three tunnel magnetoresistive sensors to P The distance between the four tunnel magnetoresistive sensors is m 2, P Four tunnel magnetoresistive sensors to P The distance of one tunnel magnetoresistive sensor is m 3; The current in the conductor under test P The magnetic field strength vector generated at point 1 The current in the conductor under test P The magnetic field intensity vectors generated at the two locations, The current in the conductor under test P The magnetic field intensity vectors generated at the three locations, The current in the conductor under test P The magnetic field strength vectors generated at 4 locations.

[0021] A three-dimensional coordinate system is established with the direction of the current to be measured as the z-axis, and the direction of the current flow is the positive z-axis. The plane perpendicular to the z-axis is the xy-plane, with the x-axis located in the xy-plane and along the direction of the linear array of tunnel magnetoresistive sensors; the y-axis is located in the xy-plane and perpendicular to the direction of the linear array of tunnel magnetoresistive sensors; all four tunnel magnetoresistive sensors are located along the sensitivity axis. S Linear arrangement P 1. P 2. P 3 and P The coordinates of position 4 are defined as ( x 1, 0, 0), ( x 2, y 2, z 2), ( x 3, y 3, z 3) and ( x 4, y 4, z 4) To facilitate sensitivity derivation and analysis, a one-dimensional linear coordinate system can also be used, i.e.: ; ; ; ; Sensitivity direction The relationship between the coordinates is as follows: ; in, This refers to the sensitivity direction vector of the tunnel magnetoresistive sensor. The magnetic field strength vector of the measured current at each location of the tunnel magnetoresistive sensor as follows: ; in, I The current intensity in the conductor to be tested. x n Let x be the x-axis coordinate of the nth tunnel magnetoresistive sensor. y n Let y be the y-axis coordinate of the nth tunnel magnetoresistive sensor.

[0022] Through magnetic field signals Calculate the magnetic field strength signal sensed by the tunnel magnetoresistive sensor. H n And construct the current calculation equation, namely: ; ; ; ; The equation set constructs four equations of the magnetic field intensity, the current size and the position relationship of the tunnel magnetoresistance sensor, eliminates the influence of the position parameter on the measurement in combination, and then directly solves the current, so that the relative position between the tunnel magnetoresistance array and the measured wire and the sensitivity offset can still be accurately solved.

[0023] Considering that iteration needs time, in order to achieve the real-time of the measured current, the transfer coefficient K , K The calculation formula is as follows: ; The average processing is adopted, and the current calculation formula is simplified as: ; In the case of no interference magnetic field, the magnetic field intensity signal sensed by the tunnel magnetoresistance sensor is as shown in Figure 2 Considering that there is an interference magnetic field in the space, the magnetic field intensity signal should have an optimal signal-to-noise ratio, and a calculation method of the transfer coefficient K with an optimal signal-to-noise ratio is proposed, and the magnetic field intensity at the signal wave peak is taken as a reference value to calculate the transfer coefficient K At this time, the signal amplitude is maximum, and the noise influence is relatively minimum. Figure 3 is a schematic diagram of the tunnel magnetoresistance sensed magnetic field intensity signal with a signal-to-noise ratio of 20dB, simulating various interference magnetic fields in the actual use. As shown in Figure 4 Under the condition of magnetic field interference, the magnetic field intensity signal sensed by the tunnel magnetoresistance sensor is directly substituted into the current calculation equation for calculation, at this time, the magnetic field signal contains a large amount of interference signal, the signal-to-noise ratio is low, and a large error will be generated, which greatly affects the measurement accuracy. Figure 5 is the calculation result of the transfer coefficient K with an optimal signal-to-noise ratio proposed in the application, the current measurement value represented by the solid line and the current reference value represented by the dashed line are basically coincided, the measurement of the measured current is better completed, the optimization calculation of the transfer coefficient K is realized for the case of large noise, and more accurate measurement of the current is realized.

[0024] In view of the existence of the interference magnetic field in the space, the Gaussian blur method is used to weaken the interference of the space interference magnetic field on the tunnel magnetoresistance sensor, resist the false wave peak caused by the interference magnetic field, and the average algorithm is used to make the selection of the wave peak more accurate.

[0025] As shown in Figure 6As shown in the figure, the circles represent the peaks taken for optimization calculation in the Gaussian blur process, and the dashed line is the magnetic field signal after Gaussian blur. It is obvious that Gaussian blur has smoothed the magnetic field signal with high noise, which can greatly resist the false peaks caused by the interference magnetic field, causing the error in the peak selection process.

[0026] As shown in the figure, the circles represent the peaks taken for optimization calculation in the Gaussian blur process, and the dashed line is the magnetic field signal after Gaussian blur. It is obvious that Gaussian blur has smoothed the magnetic field signal with high noise, which can greatly resist the false peaks caused by the interference magnetic field, causing the error in the peak selection process. Figure 7

[0027] The time constant of the Gaussian kernel is set to σ = 1ms, and the corresponding cutoff frequency is: ; Suppress high-frequency noise above 159Hz, retain fundamental and 3rd harmonic, avoid effective signal distortion, in effect equivalent to a low-pass filter, improve signal-to-noise ratio.

[0028] The signal sampling rate of the embedded processing unit is f s According to the Nyquist sampling theorem, the discrete Gaussian function is dynamically generated according to the signal sampling rate G [ i ]: ; Where N is the number of discrete sampling points, i indicates the discrete index of the elements in the Gaussian array. Through the physical time definition of σ , it is ensured that high-frequency noise can be effectively suppressed under different sampling rates.

[0029] Through Gaussian blur processing, false peaks caused by noise are avoided, and interference signals in the initial transient process are excluded. After 0.05s, the effective peaks are searched, and the number of peaks is limited to 4 or less to balance the calculation accuracy and the amount of calculation. The frequency of the measured alternating current is calculated, and the calculation formula is as follows: ; Where N peaks is the number of effective peaks, t last is the time of the first effective peak, t first is the time of the last effective peak.

[0030] The obtained peaks are averaged to minimize the interference of spatial noise on the magnetic field signal, i.e. ​ ; The magnetic field strength signal at the wave crest is averaged and substituted into the current calculation equation. The current is then calculated using Newton's iteration method. I .

[0031] The optimized current calculation value I and H peak_avg Substitute the value into the transmission coefficient K The calculation formula yields more accurate results. K The value is used to simplify current calculations.

[0032] like Figure 8 As shown, this embodiment calculates the transmission coefficient using the aforementioned Gaussian blurring, peak selection, and optimal signal-to-noise ratio method. K The current measurement results after the value is set, where the simulation signal-to-noise ratio is set to 72dB. After excluding the interference signal of the initial transient process, the detected estimated current (dashed line) coincides with the real current (solid line). It can be seen that the above method can accurately measure the magnitude and frequency of the current to be measured, with high accuracy, good effect and strong anti-interference ability.

[0033] Example 2 This embodiment provides a real-time current measurement method based on a tunnel magnetoresistive sensor, including the following steps: A linear array of tunnel magnetoresistive sensors was constructed, in which three tunnel magnetoresistive sensors were arranged in a straight line along their sensitivity direction and set at different spatial positions to collect the magnetic field strength signal excited by the current to be measured. The magnetic field strength signal is subjected to Gaussian blurring to eliminate interference signals during the initial transient process, and the effective peak positions within the stable segment are identified. Magnetic field strength signals at at least three effective peak positions with optimal signal-to-noise ratio are selected and averaged to obtain the average magnetic field strength signal. H peak_avg ; Based on the location and sensitivity direction of the tunnel magnetoresistive sensor Construct a current-solving equation based on the magnetic field strength signal to calculate the current intensity. I ; Constructing the transmission coefficient K The function is based on the average magnetic field strength signal. H peak_avg and current intensity I Obtain the transmission coefficient K ; Through the transfer coefficient K and the average magnetic field signal strength of the tunnel magnetoresistive sensor H peak_avg Perform real-time measurement of the current to be measured.

[0034] Preferably, the tunnel magnetoresistance sensor-based current real-time measurement method further comprises acquiring the frequency of the to-be-measured alternating current, specifically: After the effective peak position in the stable section is identified, the frequency of the to-be-measured alternating current is calculated f , and the calculation formula is as follows: ; Among them, N peaks is the number of peaks, t last is the appearance time of the first effective peak, t first is the appearance time of the last effective peak.

[0035] Preferably, the construction of the current solving equation is specifically: ; ; ; Among them, is the magnetic field intensity vector of the first tunnel magnetoresistance sensor, is the magnetic field intensity vector of the second tunnel magnetoresistance sensor, is the magnetic field intensity vector of the third tunnel magnetoresistance sensor, m 1 is the distance between the first tunnel magnetoresistance sensor and the second tunnel magnetoresistance sensor, m 2 is the distance between the first tunnel magnetoresistance sensor and the third tunnel magnetoresistance sensor, x 1 is the x-axis coordinate of the first tunnel magnetoresistance sensor, x 2 is the x-axis coordinate of the second tunnel magnetoresistance sensor, y 2 is the y-axis coordinate of the second tunnel magnetoresistance sensor, I is the current intensity; The current intensity is obtained by solving the current solving equation through the Newton iteration method I .

[0036] Preferably, the definition of the transfer coefficient K is as follows: ; Among them, K is the comprehensive transfer coefficient of the linear array of tunnel magnetoresistance sensors, k 1 is the transfer coefficient of the first tunnel magnetoresistance sensor, k 2 is the transfer coefficient of the second tunnel magnetoresistance sensor, k 3 is the transfer coefficient of the third tunnel magnetoresistance sensor.

[0037] Preferably, the simplified current calculation formula of the transfer coefficient K is as follows: .

[0038] Embodiment three The embodiment provides a current real-time measurement device based on a tunnel magnetoresistance sensor, comprising a tunnel magnetoresistance sensor array module and an embedded processing unit. The tunnel magnetoresistance sensor array module comprises four tunnel magnetoresistance sensors arranged in a straight line along the sensitivity direction and arranged at different spatial positions to collect the magnetic field signals excited by the measured conductor; The embedded processing unit integrates a signal acquisition and preprocessing module, a signal optimization and current calculation module and a transfer coefficient calculation module to complete real-time current size and frequency measurement on a microcontroller with limited computing resources. The signal acquisition and preprocessing module is connected with the tunnel magnetoresistance sensor array module, acquires the magnetic field signals, performs Gaussian blur processing on the magnetic field signals, identifies the effective wave peaks in the stable section and calculates the alternating current frequency. The signal optimization and current calculation module selects the magnetic field strengths at four effective wave peaks with optimal signal-to-noise ratio for average processing, constructs a current solving equation and performs optimized calculation by using the Newton iteration method. The transfer coefficient calculation module extracts the transfer coefficient dynamically through the magnetic field signals and the current K . The device can measure the size and frequency of the current in real time.

[0039] Embodiment four A computer readable storage medium is a non-volatile memory and stores computer executable instructions, and the computer executable instructions are used to execute a current real-time measurement method based on a tunnel magnetoresistance sensor. For brevity, the specific method is not described here.

[0040] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structure or direct or indirect application in other related technical fields based on the content of the present application specification and drawings is also included in the patent protection scope of the present application.

Claims

1. A real-time current measurement method based on a tunnel magnetoresistive sensor, characterized in that, Includes the following steps: Construct a linear array of tunnel magnetoresistive sensors by arranging at least three tunnel magnetoresistive sensors in a straight line along their sensitivity direction and setting them at different spatial locations to collect the magnetic field strength signal excited by the current to be measured. Magnetic field strength signals are acquired through an embedded processing unit, and Gaussian blurring is applied to eliminate interference signals during the initial transient process. Effective peak positions within the stable segment are identified, and the magnetic field strength signals at at least three effective peak positions with optimal signal-to-noise ratios are averaged to obtain the average magnetic field strength signal. H peak_avg ; Based on the location and sensitivity direction of the tunnel magnetoresistive sensor Construct a current-solving equation based on the magnetic field strength signal to calculate the current intensity. I ; Constructing the transmission coefficient K The function is based on the average magnetic field strength signal. H peak_avg and current intensity I Obtain the transmission coefficient K ; Through the transfer coefficient K and the average magnetic field strength signal of the tunnel magnetoresistive sensor H peak_avg Perform real-time measurement of the current to be measured.

2. The real-time current measurement method based on a tunnel magnetoresistive sensor according to claim 1, characterized in that, The specific method for Gaussian blurring is as follows: Set a Gaussian kernel time constant to suppress high-frequency noise above the corresponding cutoff frequency, while retaining the fundamental frequency and at least the third harmonic, wherein the cutoff frequency is ≥150Hz; Signal sampling rate of embedded processing unit f s Based on the Nyquist sampling theorem, and according to the signal sampling rate... f s Dynamic generation of discrete Gaussian functions G [ i ], and utilize G [ i The magnetic field strength signal is smoothed.

3. The real-time current measurement method based on a tunnel magnetoresistive sensor according to claim 1, characterized in that, The specific method for eliminating interference signals in the initial transient process is to start searching for effective peaks after a preset time and limit the number of effective peaks to a preset number.

4. The real-time current measurement method based on a tunnel magnetoresistive sensor according to claim 1, characterized in that, Based on the location and sensitivity direction of the tunnel magnetoresistive sensor Construct a current-solving equation based on the magnetic field strength signal to calculate the current intensity. I Specifically: Tunnel magnetoresistive sensor position and sensitivity direction The relationship between them is: ； in, This represents the sensitivity direction vector of the tunnel magnetoresistive sensor. P 1 represents the location of the first tunnel magnetoresistive sensor. P 1 = ( x 1, 0, 0). P 2 indicates the location of the second tunnel magnetoresistive sensor. P 2 = ( x 2, y 2, z 2) m 1 is P 1. Location tunnel magnetoresistive sensing and P The spacing between the two location tunnel magnetoresistive sensors; The position coordinates of the tunnel magnetoresistive sensor are defined with the direction of the current to be measured as the positive z-axis; the plane perpendicular to the z-axis is the xy-plane, with the x-axis located in the xy-plane and along the direction of the linear array of tunnel magnetoresistive sensors; the y-axis is located in the xy-plane and perpendicular to the direction of the linear array of tunnel magnetoresistive sensors. The number of tunnel magnetoresistive sensors is n, and n≥3. The magnetic field strength vector of the nth tunnel magnetoresistive sensor is... With the position coordinates and current intensity of the tunnel magnetoresistive sensor I The relationship is: ； in, x n Let x be the x-axis coordinate of the nth tunnel magnetoresistive sensor. y n Let y be the coordinate of the nth tunnel magnetoresistive sensor. The magnetic field strength signal sensed by the nth tunnel magnetoresistive sensor H n With sensitivity direction and magnetic field strength vector The relationship is: ； Construct the magnetic field strength signal of each tunnel magnetoresistive sensor H n With current intensity I The relationship is used as the equation for solving the current problem; The current intensity is obtained by solving the current equation using Newton's iteration method. I .

5. The real-time current measurement method based on a tunnel magnetoresistive sensor according to claim 1, characterized in that, The number of tunnel magnetoresistive sensors is j ,and j ≥3, the transmission coefficient K The definition of is: ； in, K The overall transmission coefficient of the linear array of tunnel magnetoresistive sensors is given. k j For the first j The transmission coefficient of a tunnel magnetoresistive sensor, H j For the first j The magnetic field strength signal sensed by a tunnel magnetoresistive sensor.

6. The real-time current measurement method based on a tunnel magnetoresistive sensor according to claim 1, characterized in that, The number of tunnel magnetoresistive sensors is j ,and j ≥3, transmission coefficient K The simplified formula for current calculation is: ； in, H n Let n be the magnetic field strength signal sensed by the nth tunnel magnetoresistive sensor. k n Let be the transmission coefficient of the nth tunnel magnetoresistive sensor. N This represents the number of magnetoresistive sensors used in the tunnel.

7. The real-time current measurement method based on a tunnel magnetoresistive sensor according to claim 1, characterized in that, It also includes acquiring the frequency of the AC current to be measured, specifically: After identifying the effective peak positions within the stable segment, the frequency of the AC current to be measured is calculated. f The calculation formula is as follows: ； in, N peaks The number of peaks, t last The time of the first valid peak. t first This refers to the time when the last valid peak appears.

8. A real-time current measurement device based on a tunnel magnetoresistive sensor, characterized in that, Includes a tunnel magnetoresistive sensor array module and an embedded processing unit; The tunnel magnetoresistive sensor array module includes at least three tunnel magnetoresistive sensors arranged in a straight line along their sensitivity direction and set at different spatial positions to collect the magnetic field intensity signal excited by the conductor under test. The embedded processing unit includes a signal acquisition and preprocessing module, a signal optimization and current calculation module, and a transmission coefficient calculation module, which performs real-time current magnitude and frequency measurement on a microcontroller with limited computing resources.

9. A real-time current measurement device based on a tunnel magnetoresistive sensor according to claim 8, characterized in that: The signal acquisition and preprocessing module is connected to the tunnel magnetoresistive sensor array module to acquire the magnetic field strength signal, perform Gaussian fuzzing on the magnetic field strength signal, identify the effective peaks in the stable section and calculate the AC current frequency. The signal optimization and current calculation module selects at least three effective peak magnetic field strengths with optimal signal-to-noise ratios for averaging, constructs current solution equations, and uses Newton's iteration method for optimization calculation. The transmission coefficient calculation module dynamically extracts the transmission coefficient using magnetic field strength signals and current. K .

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for performing the real-time current measurement method based on a tunnel magnetoresistive sensor as described in any one of claims 1 to 7.

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