Real-time Current Measurement Method, Device, and Medium Based on Tunnel Magnetoresistive Sensor

Abstract

This invention discloses a method, device, and medium for real-time current measurement based on tunnel magnetoresistive sensors, belonging to the field of non-contact current sensing. The method includes the following steps: arranging at least three tunnel magnetoresistive sensors in a straight line along their sensitivity direction to form a linear array of tunnel magnetoresistive sensors, used to acquire the magnetic field strength vector excited by the current to be measured; acquiring the magnetic field strength signal through an embedded processing unit, performing Gaussian fuzzing to eliminate interference signals in the initial transient process, identifying the effective peak position within the stable segment, and averaging the magnetic field strength signal at the effective peak position to obtain... H peak_avg The magnetic field strength signal is substituted into the current equation, and the current intensity is calculated using Newton's iteration method. I ,Will H peak_avg and I Substitute the transmission coefficients K Simplified calculations are achieved by including a tunnel magnetoresistive sensor array module and an embedded processing unit, enabling real-time measurement of current magnitude and frequency on a microcontroller with limited computing resources.

Description

Technical Field

[0001] This invention belongs to the field of non-contact current sensing, specifically relating to a method, device, and medium for real-time current measurement based on a tunnel magnetoresistive sensor. Background Technology

[0002] Current sensing technology plays a crucial role in power systems, industrial automation, new energy, and electric vehicles, and its accuracy directly impacts the development of a range of fields, including power metering, equipment protection, and intelligent control. Traditional contact-type current sensors, such as shunts and current transformers, suffer from problems such as large size and the need for contact installation. Therefore, non-contact current sensors, such as Hall effect sensors, anisotropic magnetoresistive (AMR) sensors, giant magnetoresistive (GMR) sensors, and tunnel magnetoresistive (TMR) sensors, are gradually becoming research hotspots.

[0003] Compared to traditional non-contact current sensors, TMR, as a third-generation magnetoresistive sensor, boasts advantages such as high sensitivity, low power consumption, and high accuracy, making it widely used in industries such as automotive, industrial, and consumer electronics. TMR sensors include core-type TMR sensors, coreless TMR sensors, and linear array TMR sensors. Core-type TMR sensors utilize a high-permeability magnetic core for precise measurement, but suffer from drawbacks such as large size, high cost, and magnetic saturation. Coreless TMR sensors typically exhibit a ring structure, eliminating the need for a magnetic core and coil, resulting in smaller size and weight, and easier integration. However, they require extremely precise positioning of the conductor and ring array; the conductor to be measured must pass perpendicularly through the center of the ring array. Any misalignment will introduce significant measurement errors. Furthermore, coreless TMR sensors are less resistant to external interference and are susceptible to the influence of interfering magnetic fields in space. Linear array TMR sensors simultaneously meet the requirements of light weight, small size, and high sensitivity, but still face bottlenecks in practicality and interference resistance. The first bottleneck is the transfer coefficient. K It requires DC predictors to be used in AC measurements and cannot be used alone for AC current measurement, thus its practicality is limited. Secondly, it is easily affected by spatial interference magnetic fields. If not suppressed, it will have a significant impact on the sensor's measurement, reducing the measurement accuracy or even making accurate measurement impossible. Summary of the Invention

[0004] To address the issues of poor real-time performance and weak anti-interference capability of tunnel magnetoresistive (TMR) sensors, this invention proposes a real-time current measurement method, device, and medium based on a tunnel magnetoresistive sensor.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a real-time current measurement method based on a tunnel magnetoresistive sensor, comprising the following steps:

[0007] 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.

[0008] The magnetic field signal intensity is acquired by an embedded processing unit, and Gaussian blurring is applied to the magnetic field intensity signal to eliminate interference signals in the initial transient process. The effective peak positions in the stable segment are identified, and the magnetic field intensity signals at no less than three effective peak positions with the best signal-to-noise ratio are selected and averaged to obtain the average magnetic field intensity signal. H peak_avg ;

[0009] 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 ;

[0010] 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 ;

[0011] Through the transfer coefficient K and the average magnetic field signal strength of the tunnel phrase sensor H peak_avg Perform real-time measurement of the current to be measured.

[0012] Furthermore, the specific method for Gaussian blur processing is as follows:

[0013] 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;

[0014] 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.

[0015] Set the time constant of the Gaussian kernel to be σ =1ms, corresponding to the medium frequency for:

[0016] ;

[0017] Suppress high-frequency noise above 159Hz while preserving the fundamental frequency and the third harmonic;

[0018] Based on signal sampling rate Dynamically generate discrete Gaussian functions G [ i ]:

[0019] ;

[0020] in, N The number of discrete sampling points. i This represents the discrete index of an element in a Gaussian array.

[0021] Furthermore, 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.

[0022] The magnetic field strength signal at the effective peak position is then averaged to minimize the interference of spatial noise on the magnetic field strength signal, i.e.:

[0023] ;

[0024] in H peak The signal represents the magnetic field strength at the effective peak. H peak_avg This represents the average value of the magnetic field strength signal at the effective peak.

[0025] Furthermore, 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:

[0026] Tunnel magnetoresistive sensor position and sensitivity direction The relationship between them is:

[0027] ;

[0028] 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 sensor andP 2. Spacing between the tunnel magnetoresistive sensors;

[0029] 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.

[0030] 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:

[0031] ;

[0032] 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.

[0033] 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:

[0034] ;

[0035] 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.

[0036] The current intensity is obtained by solving the current equation using Newton's iteration method. I .

[0037] Furthermore, the number of the tunnel magnetoresistive sensors is j ,and j ≥3, the transmission coefficient K The definition of is:

[0038] ;

[0039] 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, Hj For the first j The magnetic field strength signal sensed by a tunnel magnetoresistive sensor.

[0040] Furthermore, the number of the tunnel magnetoresistive sensors is j ,and j ≥3, transmission coefficient K The simplified formula for current calculation is:

[0041] ;

[0042] 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.

[0043] Furthermore, the real-time current measurement method based on a tunnel magnetoresistive sensor also includes acquiring the frequency of the AC current to be measured, specifically:

[0044] 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:

[0045] ;

[0046] in, N peaks The number of peaks, t first The time of the first valid peak. t last This refers to the time when the last valid peak appears.

[0047] Secondly, the present invention provides a real-time current measurement device based on a tunnel magnetoresistive sensor, comprising a tunnel magnetoresistive sensor array module and an embedded processing unit.

[0048] 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.

[0049] 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.

[0050] Furthermore, the signal acquisition and preprocessing module is connected to the tunnel magnetoresistive sensor array module to acquire the magnetic field strength signal, perform Gaussian fuzzy filtering on the magnetic field strength signal, identify the effective peaks in the stable section, and calculate the AC current frequency.

[0051] The signal optimization and current calculation module selects at least three effective peak magnetic field strength signals with the best signal-to-noise ratio for averaging, constructs the current solution equation, and uses Newton's iteration method for optimization calculation.

[0052] The transmission coefficient calculation module dynamically extracts the transmission coefficient using magnetic field strength signals and current. K .

[0053] Thirdly, the present invention provides a computer-readable storage medium storing computer-executable instructions for performing the real-time current measurement method based on a tunnel magnetoresistive sensor as described in any of the preceding claims.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] (1) Gaussian blurring effectively suppresses high-frequency noise, avoids noise interference leading to misjudgment of the peak, accurately obtains the magnetic field strength signal at the peak and uses it for subsequent calculations, thus improving the calculation accuracy.

[0056] (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.

[0057] (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;

[0058] (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

[0059] Figure 1 This is a schematic diagram of the linear array tunnel magnetoresistive sensor structure of the present invention;

[0060] 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.

[0061] Figure 3 This is a waveform diagram of the magnetic field strength signal detected by four tunnel magnetoresistive sensors under strong noise interference;

[0062] Figure 4 It is tradition K Comparison chart of current measurement values ​​and current reference values ​​under the current calculation method;

[0063] 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;

[0064] 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.

[0065] 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.

[0066] Figure 8 This is a diagram showing the current detection results based on the present invention. Detailed Implementation

[0067] 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.

[0068] Example 1

[0069] This embodiment provides a real-time current measurement method based on a tunnel magnetoresistive sensor, including the following steps:

[0070] 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.

[0071] 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 ;

[0072] 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 ;

[0073] Constructing the transmission coefficient K The function is based on the magnetic field strength signal. H peak_avg and current intensity IObtain the transmission coefficient K ;

[0074] Through the transfer coefficient K Perform real-time current measurement.

[0075] 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.

[0076] 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.:

[0077] ;

[0078] ;

[0079] ;

[0080] ;

[0081] Sensitivity direction The relationship between the coordinates is as follows:

[0082] ;

[0083] in, This refers to the sensitivity direction vector of the tunnel magnetoresistive sensor.

[0084] The magnetic field strength vector of the measured current at each location of the tunnel magnetoresistive sensor as follows:

[0085] ;

[0086] 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.

[0087] 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:

[0088] ;

[0089] ;

[0090] ;

[0091] ;

[0092] This set of equations establishes four equations relating magnetic field strength, current magnitude, and the position of the tunnel magnetoresistive sensor. By solving these equations simultaneously, the influence of position parameters on the measurement is eliminated, and the current can be directly solved. This allows for accurate current calculation even when the relative position and sensitivity of the tunnel magnetoresistive array and the conductor under test are offset.

[0093] Considering the time required for iteration, a transmission coefficient is introduced to achieve real-time current measurement. K , K The calculation formula is as follows:

[0094] ;

[0095] By averaging, the current calculation formula is simplified as follows:

[0096] ;

[0097] In the absence of a disturbing magnetic field, the magnetic field strength signal sensed by the tunnel magnetoresistive sensor is as follows: Figure 2 As shown. Considering the presence of interfering magnetic fields in space, and requiring the magnetic field strength signal to have an optimal signal-to-noise ratio, a transmission coefficient with the optimal signal-to-noise ratio is proposed. K The calculation method involves taking the magnetic field strength at the peak of the signal wave as a reference value and substituting it into the calculation of the transmission coefficient. K At this point, the signal amplitude is at its maximum, and the noise impact is relatively minimal. Figure 3 This is a schematic diagram of the tunnel magnetoresistive induction magnetic field strength signal with a signal-to-noise ratio of 20dB, simulating various interfering magnetic fields under actual use conditions. For example... Figure 4 As shown, under magnetic field interference, directly substituting the magnetic field strength signal sensed by the tunnel magnetoresistive sensor into the current calculation equation results in a large amount of interference signal in the magnetic field signal, a low signal-to-noise ratio, which will produce a large error and significantly affect the measurement accuracy. Figure 5 The transmission coefficient proposed in this invention K The results of the optimal signal-to-noise ratio calculation method show that the measured current value (represented by the solid line) and the reference current value (represented by the dashed line) basically coincide, indicating that the measurement of the current under test is completed well. Furthermore, it achieves good results for situations with high noise levels, including improving the transmission coefficient. K Optimized calculations enabled more accurate measurement of current.

[0098] To address the interference of magnetic fields in space, Gaussian blurring is used to weaken the interference of spatial magnetic fields on the tunnel magnetoresistive sensor, resist the false peaks caused by the interference magnetic fields, and an averaging algorithm is used to make the selection of peaks more accurate.

[0099] like Figure 6As shown, this is a simulation of the Gaussian blur effect under a 20dB signal-to-noise ratio in this embodiment. The circles represent the peaks obtained during the Gaussian blur process for optimization calculation, and the dashed lines represent the magnetic field signal after Gaussian blur. It can be clearly seen that Gaussian blur smooths the magnetic field signal with large noise, and can largely resist the false peaks caused by the interfering magnetic field, thus preventing errors in the peak selection process.

[0100] like Figure 7 The image shown is a Gaussian blur effect diagram verified in the simulation of this embodiment with a signal-to-noise ratio of 72dB.

[0101] Set the time constant of the Gaussian kernel to be σ =1ms, corresponding to the cutoff frequency have:

[0102] ;

[0103] It suppresses high-frequency noise above 159Hz, retains the fundamental frequency and the third harmonic, and avoids distortion of the effective signal. In effect, it is equivalent to a low-pass filter, improving the signal-to-noise ratio.

[0104] Signal sampling rate of embedded processing unit f s Based on the Nyquist sampling theorem, and according to the signal sampling rate... Dynamically generate discrete Gaussian functions G [ i ]:

[0105] ;

[0106] in N The number of discrete sampling points. i This represents the discrete index of an element in a Gaussian array. (The rest of the text appears to be a series of characters and symbols, possibly related to indexing or indexing.) σ The physical time definition ensures that high-frequency noise can be effectively suppressed at different sampling rates.

[0107] Gaussian blurring is used to avoid false peaks caused by noise and eliminate interference signals from the initial transient process. Valid peaks are searched after 0.05 seconds, and the number of peaks is limited to four to balance computational accuracy and computational load. The frequency of the AC current under test is calculated using the following formula:

[0108] ;

[0109] in N peaks The number of valid peaks, t last The time of the first valid peak. t first This refers to the time when the last valid peak appears.

[0110] The obtained peaks are averaged to minimize the interference of spatial noise on the magnetic field signal.

[0111] ;

[0112] 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 .

[0113] 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.

[0114] 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.

[0115] Example 2

[0116] This embodiment provides a real-time current measurement method based on a tunnel magnetoresistive sensor, including the following steps:

[0117] 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.

[0118] 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 ;

[0119] 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 ;

[0120] Constructing the transmission coefficient K The function is based on the average magnetic field strength signal. Hpeak_avg and current intensity I Obtain the transmission coefficient K ;

[0121] 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.

[0122] Preferably, the real-time current measurement method based on the tunnel magnetoresistive sensor further includes acquiring the frequency of the AC current to be measured, specifically:

[0123] 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:

[0124] ;

[0125] 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.

[0126] Preferably, the current-solving equation is constructed as follows:

[0127] ;

[0128] ;

[0129] ;

[0130] in, The magnetic field strength vector of the first tunnel magnetoresistive sensor. This represents the magnetic field strength vector of the second tunnel magnetoresistive sensor. The magnetic field strength vector of the third tunnel magnetoresistive sensor. m 1 represents the distance between the first tunnel magnetoresistive sensor and the second tunnel magnetoresistive sensor. m 2 represents the distance between the first tunnel magnetoresistive sensor and the third tunnel magnetoresistive sensor. x 1 represents the x-axis coordinate of the first tunnel magnetoresistive sensor. x 2 represents the x-axis coordinate of the second tunnel magnetoresistive sensor. y 2 represents the y-axis coordinate of the second tunnel magnetoresistive sensor. I Current intensity;

[0131] The current intensity is obtained by solving the current equation using Newton's iteration method. I .

[0132] Preferably, the transmission coefficient K The definition of is:

[0133] ;

[0134] in, K The overall transmission coefficient of the linear array of tunnel magnetoresistive sensors is given. k 1 represents the transmission coefficient of the first tunnel magnetoresistive sensor. k 2 represents the transmission coefficient of the second tunnel magnetoresistive sensor. k 3 represents the transmission coefficient of the third tunnel magnetoresistive sensor.

[0135] Preferred, transmission coefficient K The simplified formula for calculating current is:

[0136] .

[0137] Example 3

[0138] This embodiment provides a real-time current measurement device based on a tunnel magnetoresistive sensor, including a tunnel magnetoresistive sensor array module and an embedded processing unit;

[0139] The tunnel magnetoresistive sensor array module includes four tunnel magnetoresistive sensors arranged in a straight line along their sensitivity direction and set at different spatial positions to collect the magnetic field signal excited by the conductor under test.

[0140] The embedded processing unit integrates a signal acquisition and preprocessing module, a signal optimization and current calculation module, and a transmission coefficient calculation module, enabling real-time current magnitude and frequency measurement on a microcontroller with limited computing resources.

[0141] The signal acquisition and preprocessing module is connected to the tunnel magnetoresistive sensor array module to acquire magnetic field signals, perform Gaussian fuzzing on the magnetic field signals, identify effective peaks in the stable section and calculate the AC current frequency.

[0142] The signal optimization and current calculation module selects the magnetic field strength at four effective peaks with the best signal-to-noise ratio, averages them, constructs the current solution equation, and uses Newton's iteration method to optimize the calculation.

[0143] The transmission coefficient calculation module dynamically extracts the transmission coefficient through magnetic field signals and current. K ;

[0144] This device can measure the magnitude and frequency of the current in real time.

[0145] Example 4

[0146] A computer-readable storage medium is a non-volatile memory storing computer-executable instructions for executing a real-time current measurement method based on a tunnel magnetoresistive sensor. The specific method can be found in Embodiment 1, and will not be repeated here for the sake of brevity.

[0147] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure made using the contents of the present invention specification and drawings, or directly or indirectly applied to other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for real-time measurement of current based on tunneling magnetoresistance sensor, characterized in that, The method comprises the following steps: Constructing a tunnel magnetoresistance sensor linear array, arranging at least three tunnel magnetoresistance sensors in a line along the sensitivity direction of the sensors and respectively setting the sensors at different spatial positions for collecting magnetic field intensity signals excited by the current to be measured; The magnetic field intensity signal is collected by the embedded processing unit, and the magnetic field intensity signal is subjected to Gaussian blur processing, interference signals in the initial transient process are excluded, effective wave peak positions in the stable section are identified, and the magnetic field intensity signals at not less than three effective wave peak positions with optimal signal-to-noise ratios are selected for average processing to obtain an average magnetic field intensity signal H peak_avg ; According to the tunnel magnetoresistance sensor position, sensitivity direction And the magnetic field intensity signal constructs current solving equation, calculates current intensity I ; The calculated current intensity I Specifically includes: Tunneling magnetoresistance sensor position and sensitivity direction The relationship between the tunneling magnetoresistance sensor position and sensitivity direction is: ； wherein, is a tunneling magnetoresistance sensor sensitivity direction vector, P 1 is a first tunneling magnetoresistance sensor position, P 1 = (0, 0, 1), x 1, 0, 0), P 2 is a second tunneling magnetoresistance sensor position, P 2 = (0, 0, -1), x 2, y 2, z 2), m 1 is a distance between P 1 position tunneling magnetoresistance sensor and P 2 position tunneling magnetoresistance sensor; The position coordinates of the tunnel magnetoresistance sensors are set with the flow direction of the current to be measured as the positive direction of the z-axis, the plane perpendicular to the z-axis as the x-y plane, the x-axis located in the x-y plane and along the arrangement direction of the tunnel magnetoresistance sensor linear array, and the y-axis located in the x-y plane and perpendicular to the arrangement direction of the tunnel magnetoresistance sensor linear array; The number of tunnel magnetoresistance sensors is n, and n≥3, and the magnetic field intensity vector of the nth tunnel magnetoresistance sensor is The relationship between the position coordinates and the current intensity of the tunnel magnetoresistance sensor is: I The relationship between the position coordinates and the current intensity of the tunnel magnetoresistance sensor is: ； wherein, x n is an x-axis coordinate of the nth tunneling magnetoresistance sensor, y n is a y-axis coordinate of the nth tunneling magnetoresistance sensor; The magnetic field strength signal sensed by the nth tunnel magnetoresistance sensor H n with the direction of sensitivity and the magnetic field strength vector is given by ； Constructing magnetic field strength signals of individual tunnel magnetoresistance sensors H n with the current intensity I as a current solving equation; The current intensity is obtained by solving the current equation by Newton iteration method I ; Constructing the transfer coefficient K Function according to the average magnetic field strength signal H peak_avg And the current intensity I Obtaining the transfer coefficient K ; By the transmission coefficient K And the average magnetic field strength signal of a tunnel magnetoresistance sensor H peak_avg Real-time measurement of the current to be measured is carried out.

2. The current real-time measurement method based on tunneling magnetoresistance sensor according to claim 1, characterized in that, The specific method of the Gaussian blur processing is: Setting a Gaussian kernel time constant, suppressing high-frequency noise higher than a corresponding cutoff frequency under the cutoff frequency, retaining a fundamental wave and at least three harmonics, and the cutoff frequency being greater than or equal to 150 Hz; Signal sampling rate of the embedded processing unit f s According to the Nyquist sampling theorem setting, according to the signal sampling rate f s Dynamic generation of discrete Gaussian function G [ i ] and using G [ i ] to smooth the magnetic field intensity signal.

3. The current real-time measurement method based on tunneling magnetoresistance sensor according to claim 1, wherein, The specific method of excluding interference signals in the initial transient process is to start searching for effective wave crests after a preset time and limit the effective wave crests to be within a preset number.

4. The current real-time measurement method based on tunneling magnetoresistance sensor according to claim 1, wherein, The number of the tunnel magnetoresistance sensors is j , and j ≥3, the transfer coefficient K is defined as: ； wherein, K is the overall transfer function of the linear array of tunneling magnetoresistance sensors, k j is the transfer function of the first j tunneling magnetoresistance sensor, H j is the magnetic field strength signal sensed by the first j tunneling magnetoresistance sensor.

5. The current real-time measurement method based on tunneling magnetoresistance sensor according to claim 1, wherein, The number of the tunnel magnetoresistance sensors is j , and j ≥3, the transfer coefficient K The formula for simplifying current calculation is: ； wherein, H n is the magnetic field strength signal sensed by the nth tunnel magnetoresistance sensor, k n is the transducer coefficient of the nth tunnel magnetoresistance sensor, N is the number of tunnel magnetoresistance sensors.

6. The current real-time measurement method based on tunneling magnetoresistance sensor according to claim 1, wherein, The method further comprises acquiring the frequency of the alternating current to be measured, and the specific method is: After the effective wave peak position in the stable section is identified, the frequency of the to-be-tested alternating current is calculated f The calculation formula is as follows: ； wherein, N peaks is the number of peaks, t first is the time of appearance of the first significant peak, t last is the time of appearance of the last significant peak.

7. A computer readable storage medium characterized in that, The computer readable storage medium stores computer executable instructions, and the computer executable instructions are used to execute the current real-time measurement method based on the tunnel magnetoresistance sensor according to any one of claims 1 to 6.

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