A Current Measurement Method and System Based on Tunnel Magnetoresistance

Abstract

The present invention discloses a current measurement method based on tunneling magnetoresistance, which includes: constructing a magnetoresistance distribution coordinate system XOY with O as the origin around the transmission busbar, and symmetrically arranging tunneling magnetoresistance arrays on the X and Y axes of the magnetoresistance distribution coordinate system; inversely calculating the magnetic induction intensity at the position of the tunneling magnetoresistance in the tunneling magnetoresistance array according to the electrical parameter relationship; obtaining the offset relationship between the transmission busbar and the initial position of the tunneling magnetoresistance on the X and Y axes according to the magnetic induction intensity at the position of the tunneling magnetoresistance, and obtaining the position of the transmission busbar according to this position relationship so as to obtain the analytical formula of the transmission busbar current parameter; calculating the axial center position of the transmission busbar according to the magnetic induction intensity at the position of the tunneling magnetoresistance and the analytical formula of the transmission busbar current parameter; and obtaining the current of the transmission busbar according to the axial center position of the transmission busbar. The present invention can greatly improve the measurement accuracy of the busbar current.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetoresistive effect, and particularly relates to a method and system for measuring current based on tunneling magnetoresistance. Background Art

[0002] The smart grid is a modern power grid that is efficient, clean, economical, and intelligent. Advanced sensing and measurement technologies are the basis for realizing real-time monitoring, system regulation, analysis and decision-making, and fault warning of the smart grid, and are the core technologies for grid intelligence. Current, as the most basic state quantity in the power grid, its measurement technology is crucial for the development of the smart grid.

[0003] Current detection technologies are divided into contact type and non-contact type measurements according to different measurement methods. The working principle of contact type measurement is Ohm's law, and mainly uses a voltage divider to calculate the magnitude of the measured current according to the potential difference of the current flowing through the voltage divider. The working principle of non-contact type measurement is to indirectly measure the magnitude of the current by measuring the magnetic induction intensity induced by the measured current. The current sensors used include current transformers, Rogowski coils, Hall sensors, fiber optic current sensors, and magnetoresistive sensors, etc. Rogowski coil cannot accurately measure DC and low-frequency components due to its own principle defects; the essence of Hall current sensor is semiconductor material, and temperature has a great influence on it; Giant Magneto-Resistive (GMR) current sensors and Tunnel Magneto-Resistance (TMR) sensors based on magnetoresistive effect have been widely used due to their great advantages in terms of volume, sensitivity, power consumption, etc. However, the disadvantage of GMR technology is that due to its interlayer exchange coupling, the saturation magnetic field is relatively high, which will affect the sensitivity of the sensors based on GMR technology. There is no or basically no interlayer coupling between the two ferromagnetic layers in TMR materials. Only a very small external magnetic field is required to reverse the magnetization direction of one of the ferromagnetic layers, thereby realizing a huge change in tunneling resistance. Therefore, the magnetic tunnel junction structure of TMR materials has much higher magnetic field sensitivity than the metal multilayer film structure. At the same time, the magnetic tunnel junction material itself has a very high resistivity, low energy consumption, and stable performance. Therefore, as a magnetic sensor, TMR materials have more advantages than giant magnetoresistive sensors in the measurement field and have better development prospects.

[0004] The current sensors made based on the tunneling magnetoresistance effect are divided into two types: with iron cores and without iron cores. The application of the current measurement method with an iron core tunneling magnetoresistance is limited in areas with dense wiring, while the current measurement method without an iron core tunneling magnetoresistance abandons the use of an iron core, greatly reducing the non-linear defects. This sensor has a large dynamic range and a wide bandwidth, and can reliably reflect DC and harmonic components. And due to the absence of an iron core, the sensor has a very small volume and can conveniently monitor the current in areas with dense wiring. Currently, the existing current measurement methods without an iron core are based on either a circular ring type or a linear patch type. The installation of the circular ring type current sensor is relatively complex, and when only using a single-axis element, the offset position of the busbar cannot be accurately measured. Only when using a biaxial or triaxial element can the busbar offset problem be solved, but the calculation is relatively complex. The linear patch type cannot well solve the error caused by the busbar position offset. Currently, there is no good solution method in the existing literature for a current sensing device that can solve the busbar offset problem for non-circular ring types. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a current measurement method and system based on tunneling magnetoresistance, which can accurately measure the busbar current.

[0006] The technical problems to be solved by the present invention are realized through the following technical solutions:

[0007] In the first aspect, a current measurement method based on tunneling magnetoresistance is provided, including:

[0008] Construct a magnetoresistance distribution coordinate system XOY with O as the origin around the transmission busbar, and symmetrically arrange tunneling magnetoresistance arrays on the X and Y axes of this magnetoresistance distribution coordinate system;

[0009] Invert the magnetic induction intensity at the position of the tunneling magnetoresistance in the tunneling magnetoresistance array according to the electrical parameter relationship;

[0010] Obtain the offset relationship between the transmission busbar and the initial position of the tunneling magnetoresistance on the X-axis and Y-axis according to the magnetic induction intensity at the position of the tunneling magnetoresistance, and obtain the position of the transmission busbar according to this position relationship, thereby obtaining the analytical formula of the transmission busbar current parameter;

[0011] Calculate the axial center position of the transmission busbar according to the magnetic induction intensity at the position of the tunneling magnetoresistance and the analytical formula of the transmission busbar current parameter;

[0012] Obtain the current of the transmission busbar according to the axial center position of the transmission busbar.

[0013] Combined with the first aspect, further, the symmetric arrangement of the tunneling magnetoresistance arrays includes:

[0014] On any quadrant of the magnetoresistance distribution coordinate system, at least three tunnel magnetoresistances are symmetrically arranged at equal intervals along the X-axis and Y-axis directions, and a calibration tunnel magnetoresistance is arranged on the quadrant bisector, so that the distance from the axis center of the transmission bus to the origin O is less than the distance from the outermost tunnel magnetoresistance to the origin O.

[0015] Combined with the first aspect, further, the magnetic induction intensity is obtained in the following manner:

[0016] Based on the inverse derivation of the tunnel magnetoresistance from the source-load electrical parameter relationship, as shown in Equation (1):

[0017]

[0018] Among them, R xi and R yi respectively represent the resistance values of the i-th magnetoresistance on the Y-axis and X-axis, U0 is the source-end voltage of the tunnel magnetoresistance, U L is the load voltage, and R L is the load resistance value;

[0019] According to the magnetoresistance value, the magnetic induction intensity corresponding to the tunnel magnetoresistance is obtained by referring to the tunnel magnetoresistance field effect characteristic curve.

[0020] Combined with the first aspect, further, the acquisition method of the transmission bus current parameter analytical formula includes:

[0021] Arbitrarily select two tunnel magnetoresistances on the X-axis of the magnetoresistance distribution coordinate system, and select two tunnel magnetoresistances symmetric to the selected tunnel magnetoresistances on the X-axis on the Y-axis as the transmission bus position calculation array. Then, the offset relationship between the transmission bus and the initial position of the tunnel magnetoresistance is expressed as Equation (2):

[0022]

[0023] Among them, B xi and B xj are respectively the magnetic induction intensities of the i-th tunnel magnetoresistance TMR xi and the j-th tunnel magnetoresistance TMR xj on the Y-axis, B yi and B yj are respectively the magnetic induction intensities of the i-th tunnel magnetoresistance TMR yi and the j-th tunnel magnetoresistance TMR yj on the X-axis, x0 and y0 are respectively the abscissa and ordinate of the axis center of the transmission bus, y i and y j are respectively the ordinates of the i-th tunnel magnetoresistance TMR xi and the j-th tunnel magnetoresistance TMR xj on the Y-axis, and x i and x jThey are respectively the abscissas of the i-th tunneling magnetoresistance (TMR) on the X-axis yi and the j-th tunneling magnetoresistance (TMR). yj ;

[0024] According to formula (2), the coordinates of the axis center of the transmission bus can be obtained, and the current parameter analytical formula of the transmission bus is shown in formula (3):

[0025]

[0026] where μ0 is the magnetic permeability of vacuum, I is the current of the transmission bus, and R m is the distance from the calibrated tunneling magnetoresistance (TMR) m to the origin of the magnetoresistance distribution coordinate system, and x m , y m are respectively the abscissa and ordinate of the calibrated tunneling magnetoresistance.

[0027] Combined with the first aspect, further, the calculation of the axis center position of the transmission bus based on the magnetic induction intensity at the position of the tunneling magnetoresistance and the current parameter analytical formula of the transmission bus includes:

[0028] Select the first and second tunneling magnetoresistances (TMRs) on the Y-axis x1 , TMR x2 and the first and second tunneling magnetoresistances (TMRs) on the X-axis y1 , TMR y2 to construct a transmission bus calculation array A1, and select the second and third tunneling magnetoresistances (TMRs) on the Y-axis x2 , TMR x3 and the second and third tunneling magnetoresistances (TMRs) on the X-axis y2 , TMR y3 to construct a transmission bus calculation array A2; referring to formula (2), the position offset relationship between the transmission bus and the tunneling magnetoresistance in the transmission bus calculation array A1 is shown in formula (4):

[0029]

[0030] Referring to formula (2), the position offset relationship between the transmission bus and the tunneling magnetoresistance in the transmission bus calculation array A2 is shown in formula (5):

[0031]

[0032] where B x3 , B y3 are respectively the third tunneling magnetoresistance (TMR) on the Y-axis x3 and the third tunneling magnetoresistance (TMR) on the X-axis y3The magnetic induction intensity, x′0 and y′0 are respectively the abscissa and ordinate of the axis center of the transmission busbar calculated through the calculation array A1 of the transmission busbar, and x″0 and y″0 are respectively the abscissa and ordinate of the axis center of the transmission busbar calculated through the calculation array A2 of the transmission busbar.

[0033] Combined with the first aspect, further, the obtaining the current of the transmission busbar according to the axis position of the transmission busbar includes:

[0034] Select the first and second tunneling magnetoresistance TMRs on the Y-axis x1 、TMR x2 And the first and second tunneling magnetoresistance TMRs on the X-axis y1 、TMR y2 Construct a magnetic induction intensity calculation array B1, and select the second and third tunneling magnetoresistance TMRs on the Y-axis x2 、TMR x3 And the second and third tunneling magnetoresistance TMRs on the X-axis y2 、TMR y3 Construct a magnetic induction intensity calculation array B2; among them, the relationship of each parameter of B1 is expressed as:

[0035]

[0036] The relationship of each parameter of B2 is expressed as:

[0037]

[0038] Among them, I′, R′ m 、B x1 ', B y1 ' are respectively the busbar current, the calibrated tunneling magnetoresistance TMR m The distance to the axis center of the transmission busbar, the magnetic induction intensity at the position of the tunneling magnetoresistance TMR x1 The magnetic induction intensity at the position of the tunneling magnetoresistance TMR y1 Calculated according to the magnetic induction intensity calculation array B1; I″, R″ m 、B x3 ″, B y3 ″ are respectively the busbar current, the calibrated tunneling magnetoresistance TMR m The distance to the axis center of the transmission busbar, the magnetic induction intensity at the position of the tunneling magnetoresistance TMR x3 The magnetic induction intensity at the position of the tunneling magnetoresistance TMR y3 Calculated according to the magnetic induction intensity calculation array B2; y1 is the ordinate of TMR x1 The abscissa of TMR y1 x1, y3 is the ordinate of TMR x3 The abscissa of TMR y3 x3;

[0039] If the calculated B x1 ' is equal to the measured TMR x1 and the magnetic induction intensity B at the position where the TMR is located x1 is equal, and the calculated B y1 ' is equal to the measured TMR y1 and the magnetic induction intensity B at the position where the TMR is located y1 is equal, then I′ is effective;

[0040] If the calculated B x3 ″ is equal to the measured TMR x3 and the magnetic induction intensity B at the position where the TMR is located x3 is equal, and the calculated B y3 ″ is equal to the measured TMR y3 and the magnetic induction intensity B at the position where the TMR is located y3 is equal, then I″ is effective;

[0041] Add the effective I′ and I″ and divide by 2 to obtain the final transmission busbar current.

[0042] In a second aspect, the present invention further provides a current measurement system based on tunneling magnetoresistance, including:

[0043] A magnetic induction intensity acquisition module, configured to construct a magnetoresistance distribution coordinate system XOY with O as the origin around the transmission busbar, and symmetrically arrange a tunneling magnetoresistance array on the X and Y axes of the magnetoresistance distribution coordinate system;

[0044] Invert the magnetic induction intensity at the position where the tunneling magnetoresistance in the tunneling magnetoresistance array is located according to the electrical parameter relationship;

[0045] A transmission busbar current parameter analytical formula acquisition module, configured to obtain the offset relationship between the transmission busbar and the initial position of the tunneling magnetoresistance on the X and Y axes according to the magnetic induction intensity at the position where the tunneling magnetoresistance is located, and obtain the transmission busbar position according to this position relationship, thereby obtaining the transmission busbar current parameter analytical formula;

[0046] A transmission busbar position calculation module, configured to calculate the axial center position of the transmission busbar according to the magnetic induction intensity at the position where the tunneling magnetoresistance is located and the transmission busbar current parameter analytical formula;

[0047] A current calculation module, configured to obtain the current of the transmission busbar according to the axial center position of the transmission busbar.

[0048] Combined with the second aspect, further, the operations performed by the magnetic induction intensity acquisition module include:

[0049] On any quadrant of the magnetoresistance distribution coordinate system, at least three tunnel magnetoresistances are symmetrically arranged at equal intervals along the X-axis and Y-axis directions, and a calibration tunnel magnetoresistance is arranged on the quadrant bisector, so that the distance from the axis center of the power transmission bus to the origin O is less than the distance from the outermost tunnel magnetoresistance to the origin O;

[0050] Based on the tunnel magnetoresistance inverted from the source-load electrical parameter relationship, as shown in Equation (1):

[0051]

[0052] Among them, R xi and R yi respectively represent the resistance values of the i-th magnetoresistance on the Y-axis and X-axis, U0 is the source voltage of the tunnel magnetoresistance, U L is the load voltage, and R L is the load resistance value;

[0053] According to the magnetoresistance value, the magnetic induction intensity corresponding to the tunnel magnetoresistance is obtained by referring to the tunnel magnetoresistance field effect characteristic curve.

[0054] Combined with the second aspect, further, the operations performed by the power transmission bus current parameter analytical formula acquisition module include: arbitrarily selecting two tunnel magnetoresistances on the X-axis of the magnetoresistance distribution coordinate system, and selecting two tunnel magnetoresistances symmetric to the selected tunnel magnetoresistances on the X-axis on the Y-axis as the power transmission bus position calculation array. Then, the offset relationship between the power transmission bus and the initial position of the tunnel magnetoresistance is expressed as Equation (2):

[0055]

[0056] Among them, B xi and B xj are respectively the magnetic induction intensities of the i-th tunnel magnetoresistance TMR xi and the j-th tunnel magnetoresistance TMR xj on the Y-axis, B yi and B yj are respectively the magnetic induction intensities of the i-th tunnel magnetoresistance TMR yi and the j-th tunnel magnetoresistance TMR yj on the X-axis, x0 and y0 are respectively the abscissa and ordinate of the axis center of the power transmission bus, y i and y j are respectively the ordinates of the i-th tunnel magnetoresistance TMR xi and the j-th tunnel magnetoresistance TMR xj on the Y-axis, and x i and x j are respectively the abscissas of the i-th tunnel magnetoresistance TMR yi and the j-th tunnel magnetoresistance on the X-axis;

[0057] According to formula (2), the coordinates of the axis center of the transmission bus can be obtained, and the analytical formula of the current parameter of the transmission bus is shown in formula (3):

[0058]

[0059] Among them, μ0 is the magnetic permeability of vacuum, I is the current of the transmission bus, and R m is the distance from the calibrated tunnel magnetoresistance TMR m to the origin of the magnetoresistance distribution coordinate system, and x m , y m are the abscissa and ordinate of the calibrated tunnel magnetoresistance respectively.

[0060] Combined with the second aspect, further, the operations performed by the current calculation module include: selecting the first and second tunnel magnetoresistances TMR x1 , TMR x2 on the Y-axis and the first and second tunnel magnetoresistances TMR y1 , TMR y2 on the X-axis to construct the magnetic induction intensity calculation array B1, and selecting the second and third tunnel magnetoresistances TMR x2 , TMR x3 on the Y-axis and the second and third tunnel magnetoresistances TMR y2 , TMR y3 on the X-axis to construct the magnetic induction intensity calculation array B2; among them, the parameter relationships of B1 are expressed as:

[0061]

[0062] The parameter relationships of B2 are expressed as:

[0063]

[0064] Among them, I′, R′ m , B x1 ', B y1 ' are the bus current, the distance from the calibrated tunnel magnetoresistance TMR m to the axis center of the transmission bus, the magnetic induction intensity at the position of the tunnel magnetoresistance TMR x1 , and the magnetic induction intensity at the position of the tunnel magnetoresistance TMR y1 calculated according to the magnetic induction intensity calculation array B1 respectively; I″, R″ m , B x3 ″, B y3 ″ are the bus current, the distance from the calibrated tunnel magnetoresistance TMR m to the axis center of the transmission bus, the magnetic induction intensity at the position of the tunnel magnetoresistance TMR x3 , and the magnetic induction intensity at the position of the tunnel magnetoresistance TMR y3 calculated according to the magnetic induction intensity calculation array B2 respectively; y1 is TMRx1 The ordinate of, x1 is TMR y1 The abscissa of, y3 is TMR x3 The ordinate of, x3 is TMR y3 The abscissa of;

[0065] If the calculated B x1 ' is equal to the measured TMR x1 The magnetic induction intensity B at the position where it is located x1 is equal and the calculated B y1 ' is equal to the measured TMR y1 The magnetic induction intensity B at the position where it is located y1 is equal, then I′ is effective;

[0066] If the calculated B x3 ″ is equal to the measured TMR x3 The magnetic induction intensity B at the position where it is located x3 is equal and the calculated B y3 ″ is equal to the measured TMR y3 The magnetic induction intensity B at the position where it is located y3 is equal, then I″ is effective;

[0067] Add the effective I′ and I″ and divide by 2 to obtain the final transmission busbar current.

[0068] Advantageous effects: Compared with the prior art, the remarkable technical effects of the present invention are: (1) The tunneling magnetoresistance current sensor adopts a coreless single-axis multi-dimensional array structure, with low cost and low power consumption, improving the installation freedom of the current measurement device and its applicability in multiple scenarios; (2) The equidistant differential tunneling magnetoresistance position calculation method is used to accurately calculate the position parameters of the transmission busbar, and the biaxial multi-dimensional array analyzes the busbar current parameters, which can replace the traditional open-loop and closed-loop tunneling magnetoresistance current measurement methods, filling the research gap in the theory of coreless tunneling magnetoresistance current measurement, and having practical value and guiding significance; Brief description of the drawings

[0069] Figure 1 is the flow schematic diagram of the present invention;

[0070] Figure 2 is the schematic diagram of the tunneling magnetoresistance current measurement array structure in the present invention;

[0071] Figure 3 is the schematic diagram of the rotation angle of the tunneling magnetoresistance current measurement array in the present invention. Detailed implementation manners

[0072] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments.

[0073] Embodiment 1

[0074] As Figures 1 - 3 shown, the present invention provides a current measurement method based on tunneling magnetoresistance, mainly including the following steps:

[0075] Step 1: Acquisition of magnetic induction intensity

[0076] Construct a magnetoresistance distribution coordinate system XOY with O as the origin around the transmission busbar. The Y (TMR x and TMR y )-axis tunneling magnetoresistance array on the axis consists of 3 identical tunneling magnetoresistances TMR x1 , TMR x2 , TMR x3 . The tunneling magnetoresistances are equally spaced with a spacing of d. The tunneling sensitivity direction is perpendicular to the Y-axis and varies along the positive X-axis direction. TMR x1 is located on the outermost side of the array, and TMR x3 is located on the innermost side of the array. The X-axis tunneling magnetoresistance array also consists of 3 identical tunneling magnetoresistances TMR y1 , TMR y2 , TMR y3 . The tunneling magnetoresistances are equally spaced with a spacing of d. The tunneling sensitivity direction is perpendicular to the X-axis and varies along the negative Y-axis direction. TMR y1 is located on the outermost side of the array, and TMR y3 is located on the innermost side of the array. The busbar is perpendicular to the coordinate system, and the distance from the axis center of the busbar to the origin is less than the distance from the outermost tunneling magnetoresistance to the origin. The calibrated tunneling magnetoresistance TMR m is located on the quadrant bisector of the first quadrant of the XOY coordinate axis. The distances from TMR x1 , TMR y1 to the coordinate origin are R1, and the distances from TMR x3 , TMR y3 to the coordinate origin are R2, and the distance from TMR m to the coordinate origin is R m . The source-end voltage of the tunneling magnetoresistance array is U0. The resistances of the tunneling magnetoresistances TMR xi , TMR yi (i = 1, 2, 3...) are respectively R xi , R yi (i = 1, 2, 3...), the load resistance is R L , the load voltage is U L . Then, the resistances of the tunneling magnetoresistances R xi , R yi (i = 1, 2, 3...) can be inversely deduced from the source-end - load electrical parameter relationship and expressed as

[0077]

[0078] Among them, R xi and R yi respectively represent the resistance values of the i-th magnetoresistance on the Y-axis and X-axis.

[0079] By comparing with the tunnel magnetoresistance field effect characteristic curve, the tunnel magnetoresistance TMR xi 、TMR yi (i = 1, 2, 3...) and TMR m corresponding magnetic induction intensities B xi 、B yi (i = 1, 2, 3...) and B m can be obtained.

[0080] The tunnel magnetoresistances TMR xi 、TMR yi (i = 1, 2, 3...) and TMR m are all Wheatstone bridges composed of tunnel magnetoresistance elements. The internal structure of the tunnel magnetoresistance consists of four magnetosensitive resistors made based on the tunnel magnetoresistance principle, namely R a , R b , R c and R d . The four resistors are connected in the form of a Wheatstone bridge. Among them, R a and R d are located on a pair of opposite bridge arms, and R b and R c are located on another pair of opposite bridge arms. The sensitive directions of the resistors on the opposite bridge arms are the same, and the sensitive directions on the adjacent bridge arms are opposite. A positive input voltage U a is applied between R c , and it is grounded between R in and R b . The positive pole of the output voltage is located between R d and R a , and the negative pole of the output voltage is located between R b and R c . When there is no external magnetic field, the bridge is in a balanced state and the output voltage is 0; when there is an external magnetic field, the magnetosensitive resistors change with the magnetic field, the balance of the bridge is destroyed, and the output voltage U d is not 0. Since the sensitive directions of the resistors on the opposite bridge arms are the same, the resistance values are equal when the magnetic field changes, and the resistance sensitivities are the same, and the resistance change amount ΔR is the same. The resistance change of the magnetosensitive resistor and the output voltage are expressed as: out When there is no external magnetic field, the bridge is in a balanced state and the output voltage is 0; when there is an external magnetic field, the magnetosensitive resistors change with the magnetic field, the balance of the bridge is destroyed, and the output voltage U

[0081]

[0082] Step 2: Obtain the analytical formula of the transmission busbar current parameter

[0083] Arbitrarily select two tunnel magnetoresistances on the X-axis of the magnetoresistance distribution coordinate system, and select two tunnel magnetoresistances symmetric to the selected tunnel magnetoresistances on the X-axis on the Y-axis as the calculation array for the transmission bus position. Then, the offset relationship between the transmission bus and the initial position of the tunnel magnetoresistance is expressed as Equation (2):

[0084]

[0085] Among them, B xi and B xj are the magnetic induction intensities of the i-th tunnel magnetoresistance TMR xi and the j-th tunnel magnetoresistance TMR xj on the Y-axis respectively. B yi and B yj are the magnetic induction intensities of the i-th tunnel magnetoresistance TMR yi and the j-th tunnel magnetoresistance TMR yj on the X-axis respectively. x0 and y0 are the abscissa and ordinate of the axis center of the transmission bus respectively. y i and y j are the ordinates of the i-th tunnel magnetoresistance TMR xi and the j-th tunnel magnetoresistance TMR xj on the Y-axis respectively. x i and x j are the abscissas of the i-th tunnel magnetoresistance TMR yi and the j-th tunnel magnetoresistance on the Y-axis;

[0086] According to Equation (2), the coordinates of the axis center of the transmission bus can be obtained. Then, the analytical formula of the current parameter of the transmission bus is shown in Equation (3):

[0087]

[0088] Among them, μ0 is the magnetic permeability of vacuum, μ0 = 4π × 10 -7 . I is the current of the transmission bus. R m is the distance between the calibrated tunnel magnetoresistance TMR m and the origin of the magnetoresistance distribution coordinate system. x m and y m are the abscissa and ordinate of the calibrated tunnel magnetoresistance respectively.

[0089] Step 3. Obtain the bus position

[0090] Select the first and second tunnel magnetoresistances TMR x1 and TMR x2 on the Y-axis, and the first and second tunnel magnetoresistances TMR y1 and TMR y2 on the X-axis to construct the calculation array A1 of the transmission bus. Select the second and third tunnel magnetoresistances TMR x2 and TMRx3 and the second and third tunnel magnetoresistance (TMR) on the X-axis y2 TMR y3 Construct a transmission bus calculation array A2; referring to Equation (2), the position offset relationship between the transmission bus and the tunnel magnetoresistance in the transmission bus calculation array A1 is as shown in Equation (4):

[0091]

[0092] Referring to Equation (2), the position offset relationship between the transmission bus and the tunnel magnetoresistance in the transmission bus calculation array A2 is as shown in Equation (5):

[0093]

[0094] where B x3 B y3 are respectively the magnetic induction intensities of the third tunnel magnetoresistance (TMR) on the Y-axis x3 and the third tunnel magnetoresistance (TMR) on the X-axis y3 , x′0 and y′0 are respectively the abscissa and ordinate of the axis center of the transmission bus calculated through the transmission bus calculation array A1, and x″0 and y″0 are respectively the abscissa and ordinate of the axis center of the transmission bus calculated through the transmission bus calculation array A2.

[0095] Step Four: Current Calculation

[0096] Select the first and second tunnel magnetoresistance (TMR) on the Y-axis x1 TMR x2 and the first and second tunnel magnetoresistance (TMR) on the X-axis y1 TMR y2 to construct a magnetic induction intensity calculation array B1, and select the second and third tunnel magnetoresistance (TMR) on the Y-axis x2 TMR x3 and the second and third tunnel magnetoresistance (TMR) on the X-axis y2 TMR y3 to construct a magnetic induction intensity calculation array B2; the relationship of each parameter in B1 is expressed as:

[0097]

[0098] The relationship of each parameter in B2 is expressed as:

[0099]

[0100] where I′, R′ m B x1 ', B y1 ' are respectively the bus current, calibrated tunnel magnetoresistance (TMR) calculated according to the magnetic induction intensity calculation array B1 mDistance to the axis of the transmission busbar, tunneling magnetoresistance TMR x1 Magnetic induction intensity at the position, tunneling magnetoresistance TMR y1 Magnetic induction intensity at the position; I″, R″ m , B x3 ″, B y3 ″ are the busbar current and the calibrated tunneling magnetoresistance TMR calculated from the array B2 based on the magnetic induction intensity respectively m Distance to the axis of the transmission busbar, tunneling magnetoresistance TMR x3 Magnetic induction intensity at the position, tunneling magnetoresistance TMR y3 Magnetic induction intensity at the position; y1 is the ordinate of TMR x1 The abscissa of TMR is x1 y1 The ordinate of TMR is y3 x3 The abscissa of TMR is x3 y3 ;

[0101] If the calculated B x1 ' is equal to the measured TMR x1 and the magnetic induction intensity B x1 at the position where it is located, and the calculated B y1 ' is equal to the measured TMR y1 and the magnetic induction intensity B y1 at the position where it is located, then I′ is valid;

[0102] If the calculated B x3 ″ is equal to the measured TMR x3 and the magnetic induction intensity B x3 at the position where it is located, and the calculated B y3 ″ is equal to the measured TMR y3 and the magnetic induction intensity B y3 at the position where it is located, then I″ is valid;

[0103] Add the valid I′ and I″ and divide by 2 to get the final transmission busbar current.

[0104] The magnetic field around the busbar is related not only to the busbar current but also to the position of the tunneling magnetoresistance sensor. When the position and current magnitude of the busbar do not change, the larger the installation radius R m of the outermost TMR m sensor chip, the smaller the measured magnetic field. When the distance d between adjacent two TMR sensor chips does not change, Bx1 / B x2 , B x3 / B x2 , B y1 / B y2 and B y3 / B y2All four values will approach 1. Therefore, when adjusting the installation radius R of the outermost TMR sensor chip, the influence of the distance d between two adjacent TMR sensor chips cannot be ignored. When R changes, d needs to be adjusted accordingly. At the same time, there is no need to consider the rotation of the device in the XOY plane during installation. If the device rotates as shown in Figure 3 it can still be used normally.

[0105] Embodiment 2

[0106] The present invention also provides a current measurement system based on tunneling magnetoresistance, including:

[0107] A magnetic induction intensity acquisition module, configured to construct a magnetoresistance distribution coordinate system XOY with O as the origin around the transmission busbar, and symmetrically arrange a tunneling magnetoresistance array on the X and Y axes of the magnetoresistance distribution coordinate system;

[0108] Inverting the magnetic induction intensity at the position of the tunneling magnetoresistance in the tunneling magnetoresistance array according to the electrical parameter relationship;

[0109] A transmission busbar current parameter analytical formula acquisition module, configured to obtain the offset relationship between the transmission busbar and the initial position of the tunneling magnetoresistance on the X and Y axes according to the magnetic induction intensity at the position of the tunneling magnetoresistance, and obtain the transmission busbar position according to this position relationship, thereby obtaining the transmission busbar current parameter analytical formula;

[0110] A transmission busbar position calculation module, configured to calculate the axial center position of the transmission busbar according to the magnetic induction intensity at the position of the tunneling magnetoresistance and the transmission busbar current parameter analytical formula;

[0111] A current calculation module, configured to obtain the current of the transmission busbar according to the axial center position of the transmission busbar.

[0112] Among them, the operations performed by the magnetic induction intensity acquisition module include:

[0113] Symmetrically arranging no less than 3 tunneling magnetoresistances at equal intervals along the X and Y axes respectively in any quadrant of the magnetoresistance distribution coordinate system, and arranging a calibration tunneling magnetoresistance on the quadrant bisector, so that the distance from the axial center of the transmission busbar to the origin O is less than the distance from the outermost tunneling magnetoresistance to the origin O;

[0114] Inverting the tunneling magnetoresistance based on the source-load electrical parameter relationship, as shown in Equation (1):

[0115]

[0116] Where R xi and R yi respectively represent the resistance values of the i-th magnetoresistance on the Y-axis and X-axis, U0 is the source voltage of the tunneling magnetoresistance, U L is the load voltage, and R L is the load resistance;

[0117] The magnetic induction intensity corresponding to the tunneling magnetoresistance is obtained according to the tunneling magnetoresistance field effect characteristic curve with reference to the magnetoresistance value.

[0118] The operations performed by the transmission busbar current parameter analytical formula acquisition module include: arbitrarily selecting two tunneling magnetoresistances on the X-axis of the magnetoresistance distribution coordinate system, and selecting two tunneling magnetoresistances symmetric to the selected tunneling magnetoresistances on the X-axis as the transmission busbar position calculation array on the Y-axis. Then, the offset relationship between the transmission busbar and the initial position of the tunneling magnetoresistance is expressed by Equation (2):

[0119]

[0120] where B xi and B xj are the magnetic induction intensities of the ith tunneling magnetoresistance TMR xi and the jth tunneling magnetoresistance TMR xj on the Y-axis respectively, B yi and B yj are the magnetic induction intensities of the ith tunneling magnetoresistance TMR yi and the jth tunneling magnetoresistance TMR yj on the X-axis respectively, x0 and y0 are the abscissa and ordinate of the axis center of the transmission busbar, y i and y j are the ordinates of the ith tunneling magnetoresistance TMR xi and the jth tunneling magnetoresistance TMR xj on the Y-axis respectively, x i and x j are the abscissas of the ith tunneling magnetoresistance TMR yi and the jth tunneling magnetoresistance on the X-axis;

[0121] According to formula (2), the coordinates of the axis center of the transmission busbar can be obtained, and the current parameter analytical formula of the transmission busbar is as shown in Equation (3):

[0122]

[0123] where μ0 is the magnetic permeability of vacuum, I is the current of the transmission busbar, R m is the distance between the calibrated tunneling magnetoresistance TMR m and the origin of the magnetoresistance distribution coordinate system, x m and y m are the abscissa and ordinate of the calibrated tunneling magnetoresistance respectively.

[0124] Combined with the second aspect, further, the operations performed by the current calculation module include: selecting the first and second tunneling magnetoresistances TMR x1 and TMR x2 on the Y-axis, and the first and second tunneling magnetoresistances TMR on the X-axisy1 , TMR y2 Construct a magnetic induction intensity calculation array B1, and select the second and third tunnel magnetoresistance (TMR) on the Y-axis x2 , TMR x3 and the second and third tunnel magnetoresistance (TMR) on the X-axis y2 , TMR y3 Construct a magnetic induction intensity calculation array B2; among them, the relationship of each parameter of B1 is expressed as:

[0125]

[0126] The relationship of each parameter of B2 is expressed as:

[0127]

[0128] Among them, I′, R′ m , B x1 ', B y1 ' are respectively the busbar current, calibrated tunnel magnetoresistance (TMR) m to the distance from the axis of the transmission busbar, tunnel magnetoresistance (TMR) x1 the magnetic induction intensity at the position of the tunnel magnetoresistance (TMR) y1 the magnetic induction intensity at the position of the tunnel magnetoresistance (TMR); I″, R″ m , B x3 ″, B y3 ″ are respectively the busbar current, calibrated tunnel magnetoresistance (TMR) m to the distance from the axis of the transmission busbar, tunnel magnetoresistance (TMR) x3 the magnetic induction intensity at the position of the tunnel magnetoresistance (TMR) y3 the magnetic induction intensity at the position of the tunnel magnetoresistance (TMR); y1 is the ordinate of TMR x1 , x1 is the abscissa of TMR y1 , y3 is the ordinate of TMR x3 , x3 is the abscissa of TMR y3 ;

[0129] If the calculated B x1 ' is equal to the magnetic induction intensity B x1 at the position where the measured TMR x1 is located, and the calculated B y1 ' is equal to the magnetic induction intensity B y1 at the position where the measured TMR y1 is located, then I′ is valid;

[0130] If the calculated B x3 ″ is equal to the magnetic induction intensity B x3 at the position where the measured TMR x3Equal and the calculated B y3 ″ is the same as the measured TMR y3 The magnetic induction intensity B at the location where y3 they are equal, then I″ is valid;

[0131] Add the valid I′ and I″ and divide by 2 to obtain the final transmission bus current.

[0132] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the specified functions in one or more of the processes Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0133] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implement the specified functions in one or more of the processes Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0134] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in one or more of the processes Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A current measurement method based on tunneling magnetoresistance, characterized in that, Including: Construct a magnetoresistance distribution coordinate system XOY with O as the origin around the transmission busbar. Symmetrically arrange tunnel magnetoresistance arrays on the X and Y axes of the magnetoresistance distribution coordinate system, and set any point in the magnetoresistance distribution coordinate system XOY as the calibration tunnel magnetoresistance; Invert the tunnel magnetoresistance in the tunnel magnetoresistance array according to the source-terminal - load electrical parameter relationship, and then obtain the magnetic induction intensity at the position of the tunnel magnetoresistance according to the tunnel magnetoresistance with reference to the tunnel magnetoresistance field effect characteristic curve; Calculate the axial position of the transmission busbar according to the magnetic induction intensity at the position of the tunnel magnetoresistance and the analytical formula of the transmission busbar current parameters; Obtain the current of the transmission busbar according to the axial position of the transmission busbar; Wherein, the source-terminal - load electrical parameter relationship is as shown in Equation (1): Wherein, R xi and R yi respectively represent the resistance values of the i-th magnetoresistance on the X-axis and Y-axis, U0 is the source voltage of the tunneling magnetoresistance, U L is the load voltage, and R L is the load resistance value; The acquisition method of the analytical formula of the transmission busbar current parameters includes: Arbitrarily select two tunnel magnetoresistances on the X axis of the magnetoresistance distribution coordinate system, and select two tunnel magnetoresistances symmetric to the selected tunnel magnetoresistances on the X axis on the Y axis as the transmission busbar position calculation array. Then, the offset relationship between the transmission busbar and the initial position of the tunnel magnetoresistance is expressed as Equation (2): where B xi and B xj are the magnetic induction intensities of the i-th tunneling magnetoresistance TMR xi and the j-th tunneling magnetoresistance TMR xj on the Y-axis respectively, B yi and B yj are the magnetic induction intensities of the i-th tunneling magnetoresistance TMR yi and the j-th tunneling magnetoresistance TMR yj on the X-axis respectively, x0 and y0 are the abscissa and ordinate of the axis center of the transmission busbar, y i and y j are the ordinates of the i-th tunneling magnetoresistance TMR xi and the j-th tunneling magnetoresistance TMR xj on the Y-axis respectively, x i and x j are the abscissas of the i-th tunneling magnetoresistance TMR yi and the j-th tunneling magnetoresistance TMR yj on the X-axis respectively; According to Formula (2), the coordinates of the axis center of the transmission busbar can be obtained, and the analytical formula of the current parameters of the transmission busbar is as shown in Equation (3): Where, μ0 is the magnetic permeability of vacuum, I is the current of the transmission busbar, R m is the calibrated tunneling magnetoresistance TMR m distance from the origin of the coordinate system of the magnetoresistance distribution, x m and y m are the abscissa and ordinate of the calibrated tunneling magnetoresistance respectively, B m is the magnetic induction intensity at the position where the calibrated tunneling magnetoresistance TMR m is located.

2. The current measurement method based on tunneling magnetoresistance according to claim 1, characterized in that The symmetrically arranged tunnel magnetoresistance array includes: Symmetrically arrange no less than 3 tunnel magnetoresistances at equal intervals along the X and Y axes in any quadrant of the magnetoresistance distribution coordinate system, and set a calibration tunnel magnetoresistance on the quadrant bisector, so that the distance from the axis center of the transmission busbar to the origin O is less than the distance from the outermost tunnel magnetoresistance to the origin O.

3. A method for measuring current based on tunneling magnetoresistance according to claim 2, characterized in that The calculating the axial position of the transmission busbar according to the magnetic induction intensity at the position of the tunnel magnetoresistance and the analytical formula of the transmission busbar current parameters includes: Select the first and second tunnel magnetoresistance (TMR) on the Y-axis x1 , TMR x2 and the first and second tunnel magnetoresistance (TMR) on the X-axis y1 , TMR y2 to construct the transmission bus calculation array A1. Select the second and third tunnel magnetoresistance (TMR) on the Y-axis x2 , TMR x3 and the second and third tunnel magnetoresistance (TMR) on the X-axis y2 , TMR y3 to construct the transmission bus calculation array A2. Referring to Equation (2), the position offset relationship between the transmission bus and the tunnel magnetoresistance in the transmission bus calculation array A1 is shown in Equation (4): Referring to Equation (2), the position offset relationship between the transmission busbar and the tunnel magnetoresistance in the transmission busbar calculation array A2 is as shown in Equation (5): where B x3 and B y3 are respectively the magnetic induction intensities of the third tunneling magnetoresistance (TMR) on the Y-axis x3 and the third tunneling magnetoresistance (TMR) on the X-axis y3 . x0′ and y0′ are respectively the abscissa and ordinate of the axis center of the transmission busbar obtained by calculating the transmission busbar calculation array A1, and x′0′ and y′0′ are respectively the abscissa and ordinate of the axis center of the transmission busbar obtained by calculating the transmission busbar calculation array A2 4. A current measurement method based on tunneling magnetoresistance according to claim 2, wherein The obtaining the current of the transmission busbar according to the axial position of the transmission busbar includes: Select the first and second tunnel magnetoresistance (TMR) on the Y-axis x1 , TMR x2 and the first and second tunnel magnetoresistance (TMR) on the X-axis y1 , TMR y2 to construct the magnetic induction intensity calculation array B1. Select the second and third tunnel magnetoresistance (TMR) on the Y-axis x2 , TMR x3 and the second and third tunnel magnetoresistance (TMR) on the X-axis y2 , TMR y3 to construct the magnetic induction intensity calculation array B2; where the parameter relationship of B1 is expressed as: The parameter relationships of B2 are expressed as: Wherein, I′, R′ m , B x1 ', B y1 ' are respectively the busbar current, calibrated tunnel magnetoresistance TMR m from the calculated array B1 of magnetic induction intensity to the axis of the transmission busbar, the magnetic induction intensity at the position of tunnel magnetoresistance TMR x1 , the magnetic induction intensity at the position of tunnel magnetoresistance TMR y1 ; R' x is the distance between TMR x1 and the position of the busbar axis, and R' y is the distance between TMR y1 and the position of the busbar axis; I″, R′ m ′, B x3 ″, B y3 ″ are respectively the busbar current, calibrated tunnel magnetoresistance TMR m from the calculated array B2 of magnetic induction intensity to the axis of the transmission busbar, the magnetic induction intensity at the position of tunnel magnetoresistance TMR x3 , the magnetic induction intensity at the position of tunnel magnetoresistance TMR y3 ; R' x ' is the distance between TMR x3 and the position of the busbar axis, and R' y ' is the distance between TMR y3 and the position of the busbar axis; y1 is the ordinate of TMR x1 , x1 is the abscissa of TMR y1 , y3 is the ordinate of TMR x3 , and x3 is the abscissa of TMR y3 ; If the calculated B x1 ' is equal to the measured TMR x1 at the magnetic induction intensity B x1 at the location, and the calculated B y1 ' is equal to the measured TMR y1 at the magnetic induction intensity B y1 at the location, then I′ is valid; If the calculated B x3 ″ is equal to the measured TMR x3 at the magnetic induction intensity B x3 at the position, and the calculated B y3 ″ is equal to the measured TMR y3 at the magnetic induction intensity B y3 at the position, then I″ is valid; Add the effective I′ and I″ and divide the sum by 2 to obtain the final current of the transmission busbar.

5. A current measurement system based on tunneling magnetoresistance, characterized in that, Including: A magnetic induction intensity acquisition module, configured to construct a magnetoresistance distribution coordinate system XOY with O as the origin around the transmission busbar, symmetrically arrange tunnel magnetoresistance arrays on the X and Y axes of the magnetoresistance distribution coordinate system, and set any point in the magnetoresistance distribution coordinate system XOY as the calibration tunnel magnetoresistance; and invert the tunnel magnetoresistance in the tunnel magnetoresistance array according to the source-terminal - load electrical parameter relationship, and then obtain the magnetic induction intensity at the position of the tunnel magnetoresistance according to the tunnel magnetoresistance with reference to the tunnel magnetoresistance field effect characteristic curve; A transmission busbar position calculation module, configured to calculate the axial position of the transmission busbar according to the magnetic induction intensity at the position of the tunnel magnetoresistance and the analytical formula of the transmission busbar current parameters; A current calculation module, configured to obtain the current of the transmission busbar according to the axial position of the transmission busbar; Wherein, the source-terminal - load electrical parameter relationship is: wherein, R xi and R yi respectively represent the resistance values of the i-th magnetoresistance on the Y-axis and the X-axis, U0 is the source voltage of the tunneling magnetoresistance, U L is the load voltage, and R L is the load resistance value; The process of the transmission busbar position calculation module obtaining the analytical formula of the transmission busbar current parameters includes: Arbitrarily select two tunnel magnetoresistances on the X-axis of the magnetoresistance distribution coordinate system, and select two tunnel magnetoresistances symmetric to the selected tunnel magnetoresistances on the X-axis on the Y-axis as the calculation array for the transmission bus position. Then, the offset relationship between the transmission bus and the initial position of the tunnel magnetoresistance is as follows: Wherein, B xi and B xj are respectively the magnetic induction intensities of the i-th tunneling magnetoresistance TMR xi and the j-th tunneling magnetoresistance TMR xj on the Y-axis, B yi and B yj are respectively the magnetic induction intensities of the i-th tunneling magnetoresistance TMR yi and the j-th tunneling magnetoresistance TMR yj on the X-axis, x0 and y0 are respectively the abscissa and ordinate of the axis center of the transmission busbar, y i and y j are respectively the ordinates of the i-th tunneling magnetoresistance TMR xi and the j-th tunneling magnetoresistance TMR xj on the Y-axis, x i and x j are respectively the abscissas of the i-th tunneling magnetoresistance TMR yi and the j-th tunneling magnetoresistance TMR yj on the X-axis; According to formula (2), the coordinates of the axis center of the transmission bus can be obtained, and the analytical formula for the current parameters of the transmission bus is as follows: Where μ0 is the vacuum permeability, I is the current of the transmission busbar, and R m is the calibrated tunneling magnetoresistance TMR m from the origin of the coordinate system of the magnetoresistance distribution, x m and y m are the abscissa and ordinate of the calibrated tunneling magnetoresistance respectively, and B m is the magnetic induction intensity at the position where the calibrated tunneling magnetoresistance TMR m is located.

6. The current measurement system based on tunneling magnetoresistance according to claim 5, wherein The operations performed by the magnetic induction intensity acquisition module include: On any quadrant of the magnetoresistance distribution coordinate system, symmetrically set no less than 3 tunnel magnetoresistances at equal intervals along the X-axis and Y-axis directions, and set a calibration tunnel magnetoresistance on the quadrant bisector, so that the distance from the axis center of the transmission bus to the origin O is less than the distance from the outermost tunnel magnetoresistance to the origin O.

7. The current measurement system based on tunneling magnetoresistance according to claim 6, characterized in that The operations performed by the current calculation module include: selecting the first and second tunneling magnetoresistance (TMR) on the Y-axis x1 , TMR x2 and the first and second tunneling magnetoresistance (TMR) on the X-axis y1 , TMR y2 to construct a magnetic induction intensity calculation array B1, and selecting the second and third tunneling magnetoresistance (TMR) on the Y-axis x2 , TMR x3 and the second and third tunneling magnetoresistance (TMR) on the X-axis y2 , TMR y3 to construct a magnetic induction intensity calculation array B2; where the parameter relationships of B1 are expressed as: The parameter relationships of B2 are expressed as: Wherein, I′, R′ m , B x1 ', B y1 ' are respectively the busbar current, the calibrated tunneling magnetoresistance TMR m from the calculated array B1 of magnetic induction intensity to the axis of the transmission busbar, the magnetic induction intensity at the position of the tunneling magnetoresistance TMR x1 , the magnetic induction intensity at the position of the tunneling magnetoresistance TMR y1 ; R' x is the distance between the TMR x1 and the axis position of the busbar, and R' y is the distance between the TMR y1 and the axis position of the busbar; I″, R′ m ′, B x3 ″, B y3 ″ are respectively the busbar current, the calibrated tunneling magnetoresistance TMR m from the calculated array B2 of magnetic induction intensity to the axis of the transmission busbar, the magnetic induction intensity at the position of the tunneling magnetoresistance TMR x3 , the magnetic induction intensity at the position of the tunneling magnetoresistance TMR y3 ; R' x ' is the distance between the TMR x3 and the axis position of the busbar, and R' y ' is the distance between the TMR y3 and the axis position of the busbar; y1 is the ordinate of the TMR x1 , x1 is the abscissa of the TMR y1 , y3 is the ordinate of the TMR x3 , and x3 is the abscissa of the TMR y3 ; If the calculated B x1 ' is equal to the measured TMR x1 at the magnetic induction intensity B x1 at the position where it is located, and the calculated B y1 ' is equal to the measured TMR y1 at the magnetic induction intensity B y1 at the position where it is located, then I′ is valid; If the calculated B x3 ″ is equal to the measured TMR x3 at the magnetic induction intensity B x3 at the location, and the calculated B y3 ″ is equal to the measured TMR y3 at the magnetic induction intensity B y3 at the location, then I″ is valid; add the valid I′ and I″ and divide the sum by 2 to obtain the final transmission busbar current.

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