Broadband magnetic array current sensing method and device based on tunneling magnetoresistance effect

Abstract

The invention discloses a broadband magnetic array current sensing method and device based on a tunneling magnetoresistance effect. The method comprises the following steps: measuring magnetic fields at a plurality of measuring points around a measured current conductor; the measured magnetic field is utilized, the position of a measured current conductor is calculated through magnetic field inverse problem solution, and then the correlation coefficient between the measured current and the measured magnetic field is obtained through calibration; and by combining the actually measured magnetic field and the correlation coefficient obtained through calibration, the measured current is obtained through calculation. The broadband magnetic field measurement characteristic of a magnetic field sensor based on the tunneling magnetoresistance effect and the non-contact measurement advantage of magnetic array current sensing are fully utilized, and a new solution is provided for measurement of broadband, dynamic and strong random complex current signals of a power system.

Description

Technical Field

[0001] The present invention relates to the technical field of non-contact current sensing, and in particular to a broadband magnetic array current sensing method and device based on tunneling magnetoresistance effect. Background Art

[0002] With the rapid development of new power systems, large-scale new energy and power electronic equipment are continuously connected to the power grid, making the grid current present the distinctive characteristics of wideband, large dynamics, and strong randomness. However, the electromagnetic current transformers currently used in power systems can only be used for industrial frequency current measurement, and their frequency band limit is within the 1kHz frequency range, which cannot meet the new needs of the current power system for grid current measurement. Therefore, it is urgent to develop new broadband current sensing methods to meet the new needs of the current power system for sufficiently accurate measurement of broadband, large dynamic, and highly random complex current signals.

[0003] The magnetic array current sensor uses multiple magnetic field sensing units to measure the magnetic field at multiple measuring points around the measured current conductor to inversely calculate the current. It has significant advantages such as non-contact and low insulation requirements. The broadband characteristics of the magnetic array current sensor mainly depend on the frequency band of the magnetic field measured by the magnetic field sensing unit. With the rapid development of magnetic field sensing technology, a variety of magnetic field sensor devices based on different principles have been formed, such as Rogowski coils, Hall elements, and giant magnetoresistance. Among them, the magnetic field sensor device based on the tunneling magnetoresistance effect is usually composed of a layer of non-magnetic insulating material sandwiched between two magnetic material layers. When the external magnetic field changes, the resistance in the magnetic material layer of the magnetic field sensor device based on the tunneling magnetoresistance effect will change. In this way, by measuring the change in the resistance, the change in the magnetic field measured by the magnetic field sensor device can be indirectly known. This magnetic field sensor device has significant advantages such as wide bandwidth, low power consumption, fast response speed, and high sensitivity, and has been widely used in magnetic field measurement, magnetic storage and other fields. The wide-band characteristic of the magnetic field sensor based on the tunneling magnetoresistance effect enables its output voltage signal to follow the changes of the measured magnetic field signal in phase when measuring AC magnetic fields of different frequencies. Therefore, there is no need to design additional gain or phase compensation circuits to correct the gain and phase changes caused by frequency changes.

[0004] The present invention fully combines the broadband characteristics based on the tunneling magnetoresistance effect and the advantages of non-contact measurement of magnetic array sensing technology, and proposes a broadband magnetic array current sensing method and device based on the tunneling magnetoresistance effect. The broadband magnetic array current sensing device discussed is composed of three main functional modules, namely broadband magnetic field measurement, magnetic array current sensor self-calibration, and broadband current real-time measurement. Among them, the broadband magnetic field measurement module is used to measure the magnetic field at multiple measurement points around the measured current conductor; the magnetic array current sensor self-calibration module uses the measured magnetic field to solve the inverse magnetic field problem, calculates the position of the measured current conductor, and then calibrates to obtain the correlation coefficient between the measured current and the measured magnetic field; and the broadband current real-time measurement module combines the measured magnetic field and the correlation coefficient obtained by calibration, and calculates the measured current, thereby realizing the measurement of broadband current. The present invention fully utilizes the broadband magnetic field measurement characteristics of the magnetic field sensor based on the tunneling magnetoresistance effect and the advantages of non-contact measurement of magnetic array current sensing, aiming to provide a new solution for the measurement of broadband, dynamic, strong random complex current signals in power systems. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is: how to achieve high-precision non-contact measurement of broadband, large dynamic, strong random complex current signals to meet the new requirements of modern power systems for current measurement.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: A broadband magnetic array current sensing method based on tunneling magnetoresistance effect, comprising: measuring the magnetic field at multiple measurement points around the measured current conductor;

[0008] Using the measured magnetic field, the position of the measured current conductor is calculated by solving the inverse magnetic field problem, and then the correlation coefficient between the measured current and the measured magnetic field is calibrated;

[0009] The measured current is calculated by combining the measured magnetic field and the correlation coefficient obtained by calibration.

[0010] As a preferred solution of the broadband magnetic array current sensing method based on tunneling magnetoresistance effect described in the present invention, wherein: the magnetic field at multiple measuring points around the measured current conductor is measured, including a magnetic field sensing array based on tunneling magnetoresistance effect, using multiple magnetic field sensing units based on tunneling magnetoresistance effect to form an array to sense the magnetic field at multiple measuring points in the space around the measured current;

[0011] Sampling and digitizing the analog voltage signal output by each magnetic field sensing unit;

[0012] The obtained digital sampling signal is processed in combination with the calibration parameters of the magnetic field sensing unit to obtain the magnetic field measured by the magnetic field sensing unit.

[0013] As a preferred solution of the broadband magnetic array current sensing method based on tunneling magnetoresistance effect described in the present invention, wherein: the correlation coefficient between the measured current and the measured magnetic field is obtained, for a nonlinear least squares problem with the measured current and the position of the measured current conductor as unknown variables, the objective function is:

[0014]

[0015] in, is the fundamental phasor of the magnetic field, is the fundamental wave phasor of the magnetic field measured by the kth magnetic field sensing unit;

[0016] By solving the nonlinear least squares problem, the measured current is inversely calculated, and the position of the measured current conductor is determined;

[0017] And using the position information of the measured current conductor, the correlation coefficient between the measured current and the magnetic field measured by each magnetic field sensing unit is calculated to complete the self-calibration of the magnetic array current sensor. The formula is:

[0018]

[0019] Among them, the coordinates of the intersection of the measured current conductor and the xoy plane are (x I ,y I ); the kth magnetic field sensing unit, its position coordinate is The angle between its magnetic sensitivity direction and the positive direction of the x-axis is θ k ; γ k is the correlation coefficient, is the fundamental phasor of the current flowing through the measured current conductor, and μ0 is the magnetic permeability of vacuum.

[0020] As a preferred solution of the broadband magnetic array current sensing method based on tunneling magnetoresistance effect described in the present invention, wherein: the calculation to obtain the measured current includes transmitting the real-time measured magnetic field result to the broadband current real-time measurement module;

[0021] The broadband current real-time measurement module combines the measured magnetic field and the correlation coefficient obtained by calibration to calculate the measured current in real time and complete the measurement of the broadband current. k Then, the time domain magnetic field signal measured by each magnetic field sensing unit is obtained from the broadband magnetic field measurement module. Substituting it into the following formula, we can get the time domain waveform of the measured current. The formula is:

[0022]

[0023] Wherein, N is the number of magnetic field sensing units.

[0024] A broadband magnetic array current sensor device based on tunneling magnetoresistance effect, characterized by comprising a broadband magnetic field measurement module, a magnetic array current sensor self-calibration module, and a broadband current real-time measurement module;

[0025] Wideband magnetic field measurement module: measures the magnetic field at multiple measurement points around the measured current conductor;

[0026] Magnetic array current sensor self-calibration module: using the measured magnetic field, the position of the measured current conductor is calculated by solving the inverse problem of the magnetic field, and then the correlation coefficient between the measured current and the measured magnetic field is calibrated;

[0027] Broadband current real-time measurement module: The measured current is obtained by combining the measured magnetic field and the correlation coefficient obtained by calibration.

[0028] As the broadband magnetic array current sensor device based on tunneling magnetoresistance effect described in the present invention, wherein: the broadband magnetic field measurement module includes a magnetic field sensor array of tunneling magnetoresistance effect, a multi-channel analog-digital sampling unit and a digital signal processing unit;

[0029] The magnetic field sensing array based on the tunneling magnetoresistance effect uses a plurality of magnetic field sensing units based on the tunneling magnetoresistance effect to form an array, so as to sense the magnetic field at a plurality of measuring points in the space around the measured current;

[0030] The multi-channel analog-digital sampling unit is used to sample and digitize the analog voltage signal output by each magnetic field sensing unit;

[0031] The digital signal processing unit processes the obtained digitized sampling signal in combination with the calibration parameters of the magnetic field sensing unit to obtain the magnetic field measured by the magnetic field sensing unit.

[0032] As the broadband magnetic array current sensor device based on tunneling magnetoresistance effect described in the present invention, wherein: the magnetic array current sensor self-calibration module includes, for a nonlinear least squares problem with a measured current and a position of a measured current conductor as unknown variables, by quickly solving the nonlinear least squares problem, the measured current is inversely calculated, and the position of the measured current conductor is determined at the same time;

[0033] Using the position information of the measured current conductor, the correlation coefficient between the measured current and the magnetic field measured by each magnetic field sensing unit is calculated to complete the self-calibration of the magnetic array current sensor;

[0034] The broadband magnetic field measurement module also includes transmitting the magnetic field result measured in real time to the broadband current real-time measurement module;

[0035] The broadband current real-time measurement module combines the measured magnetic field with the correlation coefficient obtained by calibration to calculate the measured current in real time and complete the measurement of the broadband current.

[0036] Beneficial effects of the invention: The invention makes full use of the wide-band magnetic field measurement characteristics of the magnetic field sensor based on the tunneling magnetoresistance effect and the non-contact measurement advantages of the magnetic array current sensor, aiming to provide a new solution for the measurement of broadband, dynamic, strongly random and complex current signals in the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the figures required for use in the description of the embodiments will be briefly introduced below. Obviously, the figures described below are only some embodiments of the present invention. For ordinary technicians in this field, other figures can be obtained based on these figures without paying creative work.

[0038] Figure 1 A flow chart of a broadband magnetic array current sensing method based on tunneling magnetoresistance effect provided in the first embodiment of the present invention;

[0039] Figure 2 A specific flow chart of a broadband magnetic array current sensing method based on tunneling magnetoresistance effect provided in the first embodiment of the present invention;

[0040] Figure 3 A circuit design diagram of a magnetic field sensing unit based on tunneling magnetoresistance effect of a broadband magnetic array current sensing method based on tunneling magnetoresistance effect provided by the first embodiment of the present invention;

[0041] Figure 4 A flowchart for realizing self-calibration of a magnetic array current sensor of a broadband magnetic array current sensing method based on tunneling magnetoresistance effect provided by the first embodiment of the present invention;

[0042] Figure 5 A schematic diagram of a magnetic field generated in the surrounding space by a current under test in a broadband magnetic array current sensing method based on tunneling magnetoresistance effect provided by the first embodiment of the present invention;

[0043] Figure 6 A schematic diagram of the principle of a magnetic array current sensor containing four magnetic field sensing units for measuring a current under test in a broadband magnetic array current sensing method based on tunneling magnetoresistance effect provided by the fourth embodiment of the present invention;

[0044] Figure 7A time domain waveform diagram of a magnetic field measured by four magnetic field sensing units of a broadband magnetic array current sensing method based on tunneling magnetoresistance effect provided in a fourth embodiment of the present invention;

[0045] Figure 8 The fourth embodiment of the present invention provides a broadband magnetic array current sensing method based on tunneling magnetoresistance effect, which includes a theoretical set waveform and a measured waveform of a broadband current containing high-order harmonic components. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the specification drawings. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0047] Example 1, reference Figures 1 to 5 , is an embodiment of the present invention, and provides a broadband magnetic array current sensing method based on tunneling magnetoresistance effect, comprising:

[0048] S1: The magnetic field at multiple measuring points around the measured current conductor is measured.

[0049] The magnetic field sensing array based on the tunneling magnetoresistance effect adopts a plurality of magnetic field sensing units based on the tunneling magnetoresistance effect to form an array so as to sense the magnetic field at a plurality of measuring points in the space around the measured current.

[0050] The analog voltage signal output by each magnetic field sensing unit is sampled and digitized.

[0051] The obtained digital sampling signal is processed in combination with the calibration parameters of the magnetic field sensing unit to obtain the magnetic field measured by the magnetic field sensing unit.

[0052] Furthermore, Figure 2 The present invention is a specific flow chart for implementing a broadband magnetic array current sensing method based on tunneling magnetoresistance effect according to an embodiment of the present invention. A plurality of magnetic field sensing units based on tunneling magnetoresistance effect are installed around the current conductor to be measured to measure the magnetic field at their locations; the magnetic field sensing units based on tunneling magnetoresistance effect output analog voltage signals driven by the measured magnetic field, which are collected and digitized by a multi-channel analog-digital sampling unit; the digital signal processing unit performs a fast Fourier transform on the sampled digital voltage signal to obtain the fundamental phasor of the output voltage signal.

[0053] Since the magnetic field sensing units based on the tunneling magnetoresistance effect have a broadband characteristic, that is, within a relatively wide frequency range, the amplitude ratios between the different frequency components of the output voltage of these magnetic field sensing units and the corresponding frequency components of the measured magnetic field are equal, and the phase difference is always zero. Therefore, in order to obtain the fundamental phasor of the measured magnetic field, it is only necessary to divide the modulus of the output voltage fundamental phasor by the gain of the magnetic field sensing unit based on the tunneling magnetoresistance effect to obtain the modulus of the magnetic field fundamental phasor, and the phase of the magnetic field fundamental phasor is equal to the phase of the output voltage fundamental phasor. The circuit design of the magnetic field sensing unit based on the tunneling magnetoresistance effect proposed in the present invention is as follows: Figure 3 As shown. The magnetic field sensing unit based on the tunneling magnetoresistance effect will output an analog voltage signal under the drive of the measured magnetic field. The voltage signal is transmitted to the wide-band differential amplifier unit INA, and then converted into a single-ended output voltage signal, which is then amplified by a wide-band operational amplifier, and finally sampled and digitized by an ADC channel in the multi-channel analog-digital sampling unit.

[0054] The fundamental phasor of the magnetic field measured by each magnetic field sensing unit based on the tunneling magnetoresistance effect is fed into the magnetic array current sensor self-calibration module to calibrate the correlation coefficient between the measured current and the measured magnetic field. The calibrated correlation coefficient and the magnetic field time domain data measured by the broadband magnetic field measurement module are passed to the broadband current real-time measurement module to measure the time domain waveform of the broadband current.

[0055] S2: Using the measured magnetic field, the position of the measured current conductor is calculated by solving the inverse magnetic field problem, and then the correlation coefficient between the measured current and the measured magnetic field is calibrated.

[0056] For a nonlinear least squares problem with a measured current and a position of a measured current conductor as unknown variables, the measured current is inversely calculated by quickly solving the nonlinear least squares problem, and the position of the measured current conductor is determined at the same time.

[0057] The position information of the measured current conductor is used to calculate the correlation coefficient between the measured current and the magnetic field measured by each magnetic field sensing unit, thereby completing the self-calibration of the magnetic array current sensor.

[0058] It should be noted that in order to calibrate the magnetic array current sensor, the inverse magnetic field problem needs to be solved to determine the position of the measured current conductor, so as to calculate the correlation coefficient between the measured current and the measured magnetic field. Figure 4 First, an accurate model of the magnetic field in the space around the measured current is established, as shown in Figure 5 As shown, the measured current conductor vertically passes through the circular magnetic field sensing array composed of multiple magnetic field sensing units, and the coordinates of the intersection of the measured current conductor and the xoy plane are (x I ,yI ). For the sake of clarity, only the kth magnetic field sensing unit is shown, and its position coordinates are The angle between its magnetic sensitivity direction and the positive direction of the x-axis is θ k The fundamental phasor of the current flowing through the measured current conductor is This current phasor generates a corresponding magnetic field fundamental phasor at the location of the kth magnetic field sensing unit. The expressions of the components of the magnetic field in the x and y axis directions are as follows:

[0059]

[0060] Where μ0 is the magnetic permeability of vacuum.

[0061] The magnetic field sensed by the kth magnetic field sensing unit is expressed as follows:

[0062]

[0063] Due to the measured magnetic field It should be equal to the magnetic field calculated by equation (2), so the following equation can be obtained:

[0064]

[0065] Formula (3) is the fundamental phase of the current flowing through the conductor under test: and the intersection coordinates of the measured current conductor and the xoy plane (x I ,y I ) is a nonlinear equation with unknown quantities, and the position coordinates of the magnetic field sensor unit and magnetic sensitivity direction angle θ k All are known quantities obtained by calibration.

[0066] In order to determine the above unknown variables, at least three magnetic field sensing units are required to establish a nonlinear equation system consisting of three equations as shown in equation (3). In order to solve the above unknown variables, the above nonlinear equation system is transformed into a nonlinear least squares problem, and its objective function is defined as follows:

[0067]

[0068] in, is the fundamental phasor of the magnetic field calculated by equation (2); is the fundamental phasor of the magnetic field measured by the kth magnetic field sensing unit. Solving the above nonlinear least squares problem is to search for the optimal combination of unknown variables to minimize the deviation between the measured fundamental phasor of the magnetic field and the calculated fundamental phasor of the magnetic field.

[0069] When solving the nonlinear least squares problem with equation (4) as the objective function, certain constraints can be imposed on the variables to be solved to improve the efficiency and accuracy of the solution. Since the position of the measured current conductor is within the circular area of ​​the magnetic field sensor array, the position coordinates of the measured current conductor should satisfy the following constraint relationship, namely:

[0070]

[0071] Wherein, R is the radius of the circular magnetic field sensor array.

[0072] When the position coordinates of the conductor of the measured current are obtained After that, the correlation coefficient γ between the fundamental phasor of the measured current and the fundamental phasor of the magnetic field can be calculated according to equations (1) and (2): k , which is expressed as follows:

[0073]

[0074] From formula (6), we can see that the correlation coefficient γ k It has nothing to do with the frequency corresponding to the fundamental phasor of the current and the fundamental phasor of the magnetic field, but only with the position coordinates (x I ,y I ) and the position coordinates of the magnetic field sensing unit and magnetic sensitivity direction angle θ k Since the position coordinates and magnetic sensitive direction angle of the magnetic field sensing unit have been calibrated before leaving the factory, it is only necessary to determine the position coordinates of the measured current conductor by solving the inverse magnetic field problem.

[0075] S3: The measured current is calculated by combining the measured magnetic field and the correlation coefficient obtained by calibration.

[0076] The real-time measured magnetic field results are transmitted to the broadband current real-time measurement module.

[0077] The broadband current real-time measurement module combines the measured magnetic field and the correlation coefficient obtained by calibration to calculate the measured current in real time, thereby completing sufficiently accurate measurement of the broadband current.

[0078] It should be noted that, from formula (6), the correlation coefficient γ k It has nothing to do with the frequency corresponding to the fundamental phasor of the current and the fundamental phasor of the magnetic field, but only with the position coordinates (x I ,y I ) and the position coordinates of the magnetic field sensing unit and magnetic sensitivity direction angle θ k Since the position coordinates and magnetic sensitive direction angle of the magnetic field sensing unit have been calibrated before leaving the factory, it is only necessary to determine the position coordinates of the measured current conductor by solving the inverse magnetic field problem.

[0079] With the rapid development of new power systems, there are high-order harmonic currents in the grid current, but the proportion of harmonic components is generally relatively low, that is, the fundamental component is still dominant. Therefore, when the magnetic field fundamental phasor is measured by the magnetic field sensing unit to solve the nonlinear least squares problem with equation (4) as the objective function, the position coordinates of the measured current conductor will be calculated more accurately. When the correlation coefficient γ of each magnetic field sensing unit is determined k Then, the time domain magnetic field signal measured by each magnetic field sensing unit is obtained from the broadband magnetic field measurement module. Substituting it into the following formula, we can get the time domain waveform of the measured current, namely:

[0080]

[0081] Wherein, N is the number of magnetic field sensing units.

[0082] Embodiment 2 is the second embodiment of the present invention, which is different from the previous embodiment in that:

[0083] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the current technical solution, can be embodied in the form of a software product. The current computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0084] The logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be embodied in any computer-readable medium for use by an instruction execution device, apparatus or device (such as a computer-based device, a device including a processor, or other device that can fetch instructions from an instruction execution device, apparatus or device and execute the instructions), or in conjunction with such instruction execution device, apparatus or device. For purposes of this specification, "computer-readable medium" may be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution device, apparatus or device, or in conjunction with such instruction execution device, apparatus or device.

[0085] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0086] Embodiment 3 is an embodiment of the present invention, which provides a broadband magnetic array current sensor device based on tunneling magnetoresistance effect, characterized in that it includes a broadband magnetic field measurement module (100), a magnetic array current sensor self-calibration module (200), and a broadband current real-time measurement module (300).

[0087] The broadband magnetic field measurement module (100) measures the magnetic field at a plurality of measurement points around the measured current conductor.

[0088] A magnetic array current sensor self-calibration module (200) uses the measured magnetic field to solve the inverse problem of the magnetic field, calculates the position of the measured current conductor, and then calibrates to obtain the correlation coefficient between the measured current and the measured magnetic field.

[0089] A wideband current real-time measurement module (300) combines the measured magnetic field and the correlation coefficient obtained by calibration to obtain the measured current through calculation.

[0090] The broadband magnetic field measurement module (100) comprises three parts: a magnetic field sensor array (110) based on the tunneling magnetoresistance effect, a multi-channel analog-digital sampling unit (120), and a digital signal processing unit (130).

[0091] The magnetic field sensing array (110) based on the tunneling magnetoresistance effect uses a plurality of magnetic field sensing units based on the tunneling magnetoresistance effect to form an array, so as to sense the magnetic field at a plurality of measuring points in the space around the measured current.

[0092] The multi-channel analog-digital sampling unit (120) is used to sample and digitize the analog voltage signals output by each magnetic field sensing unit.

[0093] The digital signal processing unit (130) processes the obtained digital sampling signal in combination with the calibration parameters of the magnetic field sensing unit to obtain the magnetic field measured by the magnetic field sensing unit.

[0094] The magnetic array current sensor self-calibration module (200) comprises: for a nonlinear least squares problem with a measured current and a position of a measured current conductor as unknown variables, by quickly solving the nonlinear least squares problem, the measured current is inversely calculated, and the position of the measured current conductor is determined at the same time; and using the position information of the measured current conductor, the correlation coefficient between the measured current and the magnetic field measured by each magnetic field sensing unit is calculated to complete the self-calibration of the magnetic array current sensor.

[0095] The broadband magnetic field measurement module (100) transmits the magnetic field result measured in real time to the broadband current real-time measurement module.

[0096] The broadband current real-time measurement module (300) combines the measured magnetic field and the correlation coefficient obtained by calibration to calculate the measured current in real time, thereby completing sufficiently accurate measurement of the broadband current.

[0097] Example 4, reference Figures 6 to 8 In order to verify the effectiveness of the broadband magnetic array current sensing method and device based on tunneling magnetoresistance effect proposed in the present invention, a simulation comparison test was carried out. Four magnetic field sensing units based on tunneling magnetoresistance effect are used to form a magnetic field sensing array, which are evenly spaced and distributed in a circular ring around the current conductor to be measured. The magnetic sensitivity direction of each magnetic field sensing unit is tangential to the circular ring, such as Figure 6 As shown. The radius of the circular magnetic field sensor array is R = 20mm, and the position coordinates of the measured current conductor are (3mm, 4mm). The time domain current waveform expression of the measured current is as follows:

[0098]

[0099] Among them, ω=100π.

[0100] Under the action of current i(t), the time domain expression of the magnetic field sensed by each magnetic field sensing unit is:

[0101]

[0102] The broadband magnetic field measurement module samples and digitizes the magnetic field time domain waveform measured by each magnetic field sensing unit represented by formula (9), and obtains the magnetic field fundamental phasor through fast Fourier transform. In order to simulate the measurement error of the magnetic field sensing unit, a uniformly distributed noise with an amplitude error of ±1% is applied to the above-mentioned magnetic field fundamental phasor, and then the measured magnetic field fundamental phasor of each magnetic field sensing unit is obtained. Substitute all the measured magnetic field fundamental phasors into the nonlinear least squares problem with formula (4) as the objective function. By solving this problem, the calculated result of the position coordinates of the measured current conductor is (3mm, 3.99mm), which is basically consistent with its set value; and the modulus of the current fundamental phasor of the current-carrying conductor is 9.998A, and the phase angle is 0.5236rad, which is also consistent with its set value.

[0103] After obtaining the position coordinates of the measured current conductor, the correlation coefficient between the magnetic field measured by each magnetic field sensing unit and the measured current is calculated according to formula (6). The time domain signal of the magnetic field measured by each magnetic field sensing unit is calculated by formula (9), as follows: Figure 7 As shown, the time domain magnetic field measurement function of the broadband magnetic field measurement module is simulated; then according to formula (7), the time domain waveform of the measured current can be measured, and the result is as follows Figure 8 As shown. Figure 8 It can be seen that the time domain waveform of the measured current measured by the method proposed in the present invention is consistent with the actual current waveform.

[0104] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A broadband magnetic array current sensing method based on tunneling magnetoresistance effect, characterized in that: include: The magnetic field at multiple measuring points around the measured current conductor is measured; Using the measured magnetic field, the position of the measured current conductor is calculated by solving the inverse magnetic field problem, and then the correlation coefficient between the measured current and the measured magnetic field is calibrated; The measured current is calculated by combining the measured magnetic field and the correlation coefficient obtained by calibration.

2. The broadband magnetic array current sensing method based on tunneling magnetoresistance effect as claimed in claim 1, characterized in that: The method for measuring the magnetic field at multiple measuring points around the measured current conductor includes a magnetic field sensing array based on the tunneling magnetoresistance effect, which uses multiple magnetic field sensing units based on the tunneling magnetoresistance effect to form an array to sense the magnetic field at multiple measuring points in the space around the measured current; Sampling and digitizing the analog voltage signal output by each magnetic field sensing unit; The obtained digital sampling signal is processed in combination with the calibration parameters of the magnetic field sensing unit to obtain the magnetic field measured by the magnetic field sensing unit.

3. The broadband magnetic array current sensing method based on tunneling magnetoresistance effect as claimed in claim 2, characterized in that: The obtaining of the correlation coefficient between the measured current and the measured magnetic field includes solving a nonlinear least squares problem with the measured current and the position of the measured current conductor as unknown variables, and the objective function is: in, is the fundamental phasor of the magnetic field, is the fundamental wave phasor of the magnetic field measured by the kth magnetic field sensing unit; By solving the nonlinear least squares problem, the measured current is inversely calculated, and the position of the measured current conductor is determined; And using the position information of the measured current conductor, the correlation coefficient between the measured current and the magnetic field measured by each magnetic field sensing unit is calculated to complete the self-calibration of the magnetic array current sensor. The formula is: Among them, the coordinates of the intersection of the measured current conductor and the xoy plane are (x I ,y I ); the kth magnetic field sensing unit, its position coordinate is The angle between its magnetic sensitivity direction and the positive direction of the x-axis is θ k ; γ k is the correlation coefficient, is the fundamental phasor of the current flowing through the measured current conductor, and μ0 is the magnetic permeability of vacuum.

4. The broadband magnetic array current sensing method based on tunneling magnetoresistance effect as claimed in claim 3, characterized in that: The calculating and obtaining the measured current includes transmitting the real-time measured magnetic field result to the broadband current real-time measurement module; The broadband current real-time measurement module combines the measured magnetic field and the correlation coefficient obtained by calibration to calculate the measured current in real time and complete the measurement of the broadband current. k Then, the time domain magnetic field signal measured by each magnetic field sensing unit is obtained from the broadband magnetic field measurement module. Substituting it into the following formula, we can get the time domain waveform of the measured current. The formula is: Wherein, N is the number of magnetic field sensing units.

5. A broadband magnetic array current sensor device based on tunneling magnetoresistance effect using the method according to any one of claims 1 to 4, characterized in that: It includes a broadband magnetic field measurement module, a magnetic array current sensor self-calibration module, and a broadband current real-time measurement module; Wideband magnetic field measurement module: measures the magnetic field at multiple measurement points around the measured current conductor; Magnetic array current sensor self-calibration module: using the measured magnetic field, the position of the measured current conductor is calculated by solving the inverse problem of the magnetic field, and then the correlation coefficient between the measured current and the measured magnetic field is calibrated; Broadband current real-time measurement module: The measured current is obtained by combining the measured magnetic field and the correlation coefficient obtained by calibration.

6. The broadband magnetic array current sensor device based on tunneling magnetoresistance effect as claimed in claim 5, characterized in that: The broadband magnetic field measurement module includes a magnetic field sensor array of tunneling magnetoresistance effect, a multi-channel analog-digital sampling unit and a digital signal processing unit; The magnetic field sensing array based on the tunneling magnetoresistance effect uses a plurality of magnetic field sensing units based on the tunneling magnetoresistance effect to form an array, so as to sense the magnetic field at a plurality of measuring points in the space around the measured current; The multi-channel analog-digital sampling unit is used to sample and digitize the analog voltage signal output by each magnetic field sensing unit; The digital signal processing unit processes the obtained digitized sampling signal in combination with the calibration parameters of the magnetic field sensing unit to obtain the magnetic field measured by the magnetic field sensing unit.

7. The broadband magnetic array current sensor device based on tunneling magnetoresistance effect as claimed in claim 6, characterized in that: The magnetic array current sensor self-calibration module includes, for a nonlinear least squares problem with a measured current and a position of a measured current conductor as unknown variables, by quickly solving the nonlinear least squares problem, inversely calculating the measured current and determining the position of the measured current conductor; By using the position information of the measured current conductor, the correlation coefficient between the measured current and the magnetic field measured by each magnetic field sensing unit is calculated to complete the self-calibration of the magnetic array current sensor; The broadband magnetic field measurement module also includes transmitting the magnetic field result measured in real time to the broadband current real-time measurement module; The broadband current real-time measurement module combines the measured magnetic field with the correlation coefficient obtained by calibration to calculate the measured current in real time and complete the measurement of the broadband current.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

Images