CN212111561U - A follower current measurement device based on tunnel magnetoresistance chip - Google Patents

Abstract

The utility model discloses a follower current measuring device based on a tunnel magnetoresistance chip. The device comprises: a V-shaped slot part and a U-shaped slot part; the U-shaped slot part includes a linear displacement sensor and a tunnel magnetoresistance chip; The groove sections of the groove parts and the V-shaped groove parts are symmetrical along the central axis; the grooves of the U-shaped groove parts are placed opposite to the grooves of the V-shaped groove parts; the symmetry axis of the groove cross-section of the U-shaped groove parts is the same as that of V The symmetry axis of the groove section of the groove-shaped component coincides; the displacement direction of the linear displacement sensor coincides with the symmetry axis; the tunnel magnetoresistive chip is arranged on the top of the linear displacement sensor and is perpendicular to the symmetry axis; when measuring, the The energized wire to be tested is placed between the V-shaped groove parts and the U-shaped groove parts placed opposite, and is fastened and fixed by the linear displacement sensor and the V-shaped groove; the current direction of the energized wire is the same as that marked on the tunnel magnetoresistive chip. Magnetic field sensitive directions follow Ampere's law.

Description

A follower current measurement device based on tunnel magnetoresistance chip

technical field

The utility model relates to the field of electric power technology, and more particularly, to a follower current measuring device based on a tunnel magnetoresistive chip.

Background technique

Current is the basic measurement object for energy consumption monitoring. Currently, current sensors measure current based on several physical principles. The first is a shunt based on Ohm's law. The output voltage at both ends is proportional to the measured current. It has the advantages of low cost and convenient application. It can meet the current measurement applications of general requirements and is still widely used. However, shunts are placed in series in the circuit, and their limitations are also obvious: large losses and no electrical isolation when measuring large currents. Therefore, when used in an environment that requires electrical isolation, additional electrical isolation measures, such as isolation amplifiers, are required, resulting in increased cost and reduced bandwidth. The second is the current sensor based on Ampere's loop law, which indirectly measures the magnitude and direction of the current by measuring the magnetic field, and has electrical insulation between the primary and secondary sides. Current sensors used in industrial applications are usually based on the following five measurement technologies: Hall (HALL) current sensors; fluxgate (fluxgate) current sensors; magnetoresistive (MR) current sensors, including anisotropic magnetoresistive (AMR) current sensors ), giant magnetoresistance (GMR), tunnel magnetoresistance (TMR); Rogowski coil and current transformer. There are other current sensors of indirect measurement techniques. It mainly uses the combination of magnetic field and other physical principles or effects to realize the indirect measurement of current. Including Faraday effect magneto-optic effect (magneto-optic), nuclear magnetic resonance NMR (nuclear mag-neticresonance), magnetostriction effect (magnetostriction effect), quantum Hall effect (quantum Hall effect), superconducting quantum interference device SQUID and so on. These technologies and their products target different market segments and have different characteristics. For example, current sensors based on NMR, quantum Hall effect and SQUID have high requirements for the application environment and high price, and are used in a small amount of laboratory equipment. So far, some technologies are immature and are in the development or improvement stage; Faraday-based The current sensor with magneto-optical effect has good performance in measuring AC large current (such as 100kA), but when measuring DC, the performance problem needs to be solved urgently.

On-device measurement extends state awareness to customer's internal energy-consuming equipment. Through the extensive access of on-board devices, a wealth of energy production, consumption, and degradation operation data can be collected to create a comprehensive state perception, efficient information processing, and smart energy use. Ubiquitous power internet of things. However, the current current measurement methods are mostly based on the form of transformers, which are generally large in size, and cannot meet the requirements of small size, wide deployment, and low cost for accompanying device measurement.

Utility model content

In order to solve the problem in the background art that the measurement volume of the existing current measurement method is large and cannot meet the requirements of the follower measurement, the utility model provides a follower current measurement device based on a tunnel magnetoresistive chip; the device does not need a transformer Measure the current; monitor the magnetic field characteristics near the energized wire through the tunnel magnetoresistance chip, and calculate the magnitude of the current therein; the device for measuring the current of the follower based on the tunnel magnetoresistance chip includes:

A V-shaped groove part and a U-shaped groove part; the U-shaped groove part includes a linear displacement sensor and a tunnel magnetoresistive chip;

The groove cross section of the U-shaped groove part is left-right symmetrical along the central axis; the groove cross-section of the V-shaped groove part is left-right symmetrical along the central axis;

the relative placement of the groove of the U-shaped groove part and the groove of the V-shaped groove part; the symmetry axis of the groove cross section of the U-shaped groove part coincides with the symmetry axis of the groove cross section of the V-shaped groove part;

The linear displacement sensor is arranged at the intersection of the U-shaped groove section and the symmetry axis, and the displacement direction of the linear displacement sensor coincides with the symmetry axis;

The tunnel magnetoresistive chip is arranged on the top of the linear displacement sensor and is perpendicular to the symmetry axis;

During the measurement, the energized wire to be tested is placed between the V-shaped groove parts and the U-shaped groove parts placed oppositely, and is fastened and fixed by the linear displacement sensor and the V-shaped groove; the current direction of the energized wire is related to the tunnel magnetoresistance. The magnetic field sensitive direction marked on the chip follows Ampere's law.

Further, one side of the groove of the U-shaped groove part is hinged with one side of the groove of the V-shaped groove part, and can be rotated in a direction perpendicular to the groove cross-section;

The other side of the groove of the U-shaped groove part and one side of the groove of the V-shaped groove part are connected by snaps.

Further, the tunnel magnetoresistive chip is arranged on the top of the linear displacement sensor, including:

A magneto-sensitive probe is arranged on the top of the linear displacement sensor; the material of the magneto-sensitive probe includes flame retardant plastic;

The tunnel magnetoresistive chip is mounted on the PCB board and packaged inside the magneto-sensitive probe to ensure that the tunnel magnetoresistive chip is perpendicular to the symmetry axis.

Further, the device also includes a computing unit;

The linear displacement sensor is used to collect the linear displacement of the sensor after the device is put into the energized wire to be tested; the output end of the linear displacement sensor is connected to the input end of the computing unit;

The tunnel magnetoresistance chip is used for collecting the analog differential signal affected by the magnetic field strength; the output end of the tunnel magnetoresistance chip is connected with the input end of the computing unit;

The calculation unit is configured to calculate and obtain the current value of the energized wire to be tested according to the linear displacement amount and the analog differential signal.

Further, the calculation unit is configured to calculate and obtain the magnetic field strength according to the received analog differential signal;

The calculation unit is configured to calculate and obtain the distance between the tunnel magnetoresistive chip and the center of the wire according to the received linear displacement;

The calculation unit is configured to calculate and obtain the current value of the conducting wire to be tested according to the magnetic field strength and the distance between the tunnel magnetoresistive chip and the center of the wire.

Further, when the angle of the V-shaped angle of the groove section of the V-shaped groove component is 90 degrees; the calculation method of the current I is:

Wherein, μ ₀ is the magnetic permeability of air; h is the linear displacement amount, that is, the distance that the linear displacement sensor moves with the vertex of the V-shaped angle as the starting point during measurement; B is the magnetic field strength.

Further, a level is provided on the surface of the V-shaped groove part and the U-shaped groove part; the two levels are parallel to each other when the V-shaped groove part and the U-shaped groove part are placed opposite each other;

An elastic buffer material is provided on the contact surfaces of the V-shaped groove part and the U-shaped groove part when they are placed oppositely;

The buckle connected with the V-shaped groove part and the U-shaped groove part includes an adjustable and elastic locking part;

Before the measurement, the indications of the two levels are adjusted to remain the same by adjusting the locking member.

The beneficial effects of the present utility model are as follows: the technical scheme of the present utility model provides a follower current measurement device based on a tunnel magnetoresistance chip, which does not require a transformer to measure current; the tunnel magnetoresistance chip monitors the vicinity of the energized wire magnetic field characteristics, and calculate the current size in it; the device makes full use of the characteristics of the tunnel magnetoresistive chip with high sensitivity, low power consumption, low noise floor, wide dynamic range, and low hysteresis, which meets the requirements of the current sensor used in the follower measurement. High-precision miniaturized design requirements. The device realizes the refined management of the power consumption of different electrical appliances by measuring the current of the electrical appliances, and lays a strong foundation for saving energy and reducing consumption.

Description of drawings

Exemplary embodiments of the present invention can be more fully understood by referring to the following drawings:

FIG. 1 is a structural diagram of a follower current measurement device based on a tunnel magnetoresistive chip according to a specific embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for the purpose of being thorough and complete. The present invention is disclosed and the scope of the present invention is fully conveyed to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the invention. In the drawings, the same elements/elements are given the same reference numerals.

Unless otherwise defined, terms (including scientific and technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is to be understood that terms defined in commonly used dictionaries should be construed as having meanings consistent with the context in the related art, and should not be construed as idealized or overly formal meanings.

1 is a structural diagram of a device for measuring follower current based on a tunnel magnetoresistive chip according to a specific embodiment of the present invention; as shown in FIG. 1 , the device includes:

The V-shaped groove part 120 and the U-shaped groove part 110; the U-shaped groove part 110 includes a linear displacement sensor 111 and a tunnel magnetoresistive chip 112;

The groove cross-section of the U-shaped groove member 110 is left-right symmetrical along the central axis; the groove cross-section of the V-shaped groove member 120 is left-right symmetrical along the central axis;

As shown in FIG. 1 , in this embodiment, the groove cross section of the U-shaped groove member 110 is a semicircle, and the line connecting the highest point of the semicircle and the center of the semicircle is on the central axis; however, the groove cross section not only includes a semicircle , and also includes left-right symmetrical U-shaped groove cross-sections of other shapes;

The groove cross section of the V-shaped groove member 120 is an isosceles triangle. In particular, for the convenience of calculation, the isosceles triangle can be an equilateral triangle or an isosceles right triangle; in this embodiment, the groove cross section is preferably selected as An isosceles right triangle whose lowest point is a right angle;

The relative placement of the groove of the U-shaped groove part 110 and the groove of the V-shaped groove part 120 ; coincide;

The relative placement described in this embodiment refers to the manner shown in FIG. 1 , that is, the groove and the groove are opposite to each other to form a space area that is generally a U-shaped space and half a V-shaped space, and this space area is used for placing The energized wire to be tested;

When the energized wire to be tested is placed in the space area, the highest point of the U-shaped groove section, the center of the semicircle where the U-shaped groove section is located (or the corresponding position of other groove sections), the center of the energized wire section, and the V-shaped groove The lowest point of the section, the four points are located on the same line, and the said axis of symmetry.

The linear displacement sensor 111 is arranged at the intersection of the U-shaped groove section and the symmetry axis, and the displacement direction of the linear displacement sensor 111 coincides with the symmetry axis;

The tunnel magnetoresistive chip 112 is disposed on the top of the linear displacement sensor 111 and is perpendicular to the symmetry axis;

As shown in FIG. 1 , in this embodiment, the linear vertical sensor is a sliding resistance linear displacement sensor 111, which detects the displacement distance of the sensor; the displacement direction of the linear displacement sensor 111 coincides with the symmetry axis. the linear displacement sensor 111 moves on the symmetry axis;

A magneto-sensitive probe is arranged on the top of the linear displacement sensor 111; the material of the magneto-sensitive probe can be flame-retardant plastic; further, the surface of the U-shaped groove part 110 and the V-shaped groove part 120 in contact with the energized wire to be tested All materials can be flame retardant plastics to ensure safety during measurement.

The tunnel magnetoresistive chip 112 is mounted on the PCB board and packaged inside the magneto-sensitive probe to ensure that the tunnel magnetoresistive chip 112 is perpendicular to the symmetry axis. The tunnel magnetoresistive chip 112 is a patch-like structure, and the perpendicular to the symmetry axis means that when the tunnel magnetoresistive chip 112 is abstracted into a plane, the plane is perpendicular to the symmetry axis, which makes the The magnetic field cutting effect is the best when measuring energized wires;

In addition, since the magnetic field sensitive direction is marked on the tunnel magnetoresistive chip 112 , when packaging the tunnel magnetoresistive chip 112 , attention should be paid to the packaging direction to ensure that the magnetic field sensitive direction of the tunnel magnetoresistive chip 112 is consistent with the current to be tested. The magnetic field formed by the wire can be consistent in the direction of the magnetic field under Ampere's law.

Further, one side of the groove of the U-shaped groove member 110 is hinged with one side of the groove of the V-shaped groove member 120, and can be rotated in a direction perpendicular to the cross section of the groove; the groove of the U-shaped groove member 110 The other side of the V-shaped groove part 120 is connected with one side of the groove by snaps.

In this embodiment, in order to ensure that the position of the energized wire is relatively fixed during measurement, the U-shaped groove part 110 and the V-shaped groove part 120 can be fastened by the above-mentioned connection method; only one connection method is provided in this embodiment, but It should be noted that, other methods that can make the U-shaped groove part 110 and the V-shaped groove part 120 fixedly connect and make the position of the energizing wire relatively fixed can be applied to the device.

Further, in order to improve the accuracy and sensitivity of the device, during measurement, the axes of symmetry of the V-shaped groove member 120 and the U-shaped groove member 110 should be kept coincident; based on this, the V-shaped groove member 120 and the U-shaped groove member Levels are provided on the surface of the 110; the two levels are parallel to each other when the V-shaped groove part 120 and the U-shaped groove part 110 are placed opposite each other; when the two levels are in the same horizontal state, the V-shaped groove part 120 And the axis of symmetry of the U-shaped groove part 110 is at least parallel. Due to the connection method described above, the relative positions of the V-shaped groove part 120 and the U-shaped groove part 110 in the lateral direction are fixed, so when the V-shaped groove part 120 and the U-shaped groove part 110 are fixed When the axes of symmetry of the groove member 120 and the U-shaped groove member 110 are parallel, the two axes of symmetry coincide.

In order to ensure that the horizontal state of the V-shaped groove member 120 and the U-shaped groove member 110 can be relatively adjusted, elastic buffer materials are provided on the contact surfaces of the V-shaped groove member 120 and the U-shaped groove member 110 when they are placed relative to each other; The buckle connecting the V-shaped groove part 120 and the U-shaped groove part 110 includes a locking part that can adjust the tightness; before the measurement, the indications of the two levels are adjusted by adjusting the locking part. same.

In this embodiment, the locking member may be a fastener with a limiting function, such as a bolt and nut.

During the measurement, the energized wire to be tested is placed between the V-shaped groove part 120 and the U-shaped groove part 110 placed oppositely, and is fastened and fixed by the linear displacement sensor 111 and the V-shaped groove; the current direction of the energized wire is the same as that of the The magnetic field sensitive direction marked on the tunnel magnetoresistive chip 112 follows Ampere's law.

Further, the device also includes a computing unit;

The linear displacement sensor 111 is used to collect the linear displacement of the sensor after the device is put into the energized wire to be tested; the output end of the linear displacement sensor 111 is connected to the input end of the computing unit;

The tunnel magnetoresistance chip 112 is used for collecting analog differential signals affected by the magnetic field strength; the output end of the tunnel magnetoresistance chip 112 is connected to the input end of the computing unit;

The calculation unit is configured to calculate and obtain the current value of the energized wire to be tested according to the linear displacement amount and the analog differential signal.

Specifically, the calculation unit is configured to calculate and obtain the magnetic field strength according to the received analog differential signal; the V+ pin and the V- pin of the tunnel magnetoresistive chip 112 and the output analog differential signal, the analog differential signal and the The magnitude of the magnetic field where the tunnel magnetoresistive chip 112 is located has a linear relationship, so the magnetic field intensity value can be obtained by simulating the differential signal through a preset proportional parameter.

The calculation unit is configured to calculate and obtain the distance between the tunnel magnetoresistive chip 112 and the center of the wire according to the received linear displacement; when the energized wire to be measured is not placed in the device, the linear displacement sensor 111 It can be located at the lowest end position of the groove section of the V-shaped groove member 120. When the energized wire to be measured is placed in the device, an example of the movement of the linear displacement sensor 111 is to calculate the required distance between the tunnel magnetoresistive chip 112 and the center of the wire. distance; if the linear displacement sensor 111 is not at the lowest end position of the groove section of the V-shaped groove part 120 when the energized wire to be tested is not placed in the device, its position should be determined, Through its moving distance and its original position, the distance between the tunnel magnetoresistive chip 112 and the center of the wire can still be calculated.

The calculation unit is configured to calculate and obtain the current value of the conducting wire to be tested according to the magnetic field strength and the distance between the tunnel magnetoresistive chip 112 and the center of the wire.

It can be known that the calculation method of the current I to the county is:

I=2πr*μ ₀ *B

In this embodiment, the calculation is only performed when the angle of the V-shaped angle of the groove section of the V-shaped groove member 120 is 90 degrees: the calculation method of the current I is:

Wherein, μ ₀ is the magnetic permeability of air; h is the linear displacement, that is, the distance that the linear displacement sensor 111 moves with the vertex of the V-shaped angle as the starting point during measurement; r is the wire diameter of the wire ; B is the magnetic field strength.

The above are only specific embodiments of the present disclosure. It should be pointed out that for those skilled in the art, several improvements, modifications, and variations can be made without departing from the spirit of the present disclosure. These improvements, Modifications and deformations should be regarded as falling within the protection scope of the present application.

Claims (8)

1. A follower current measuring device based on a tunnel magnetoresistive chip, characterized in that: the device comprises: a V-shaped groove part and a U-shaped groove part; the U-shaped groove part comprises a linear displacement sensor and a tunnel magnetoresistive chip ; The groove cross section of the U-shaped groove part is left-right symmetrical along the central axis; the groove cross-section of the V-shaped groove part is left-right symmetrical along the central axis; the relative placement of the groove of the U-shaped groove part and the groove of the V-shaped groove part; the symmetry axis of the groove cross section of the U-shaped groove part coincides with the symmetry axis of the groove cross section of the V-shaped groove part; The linear displacement sensor is arranged at the intersection of the U-shaped groove section and the symmetry axis, and the displacement direction of the linear displacement sensor coincides with the symmetry axis; The tunnel magnetoresistive chip is arranged on the top of the linear displacement sensor and is perpendicular to the symmetry axis; During the measurement, the energized wire to be tested is placed between the V-shaped groove parts and the U-shaped groove parts placed oppositely, and is fastened and fixed by the linear displacement sensor and the V-shaped groove; the current direction of the energized wire is related to the tunnel magnetoresistance. The magnetic field sensitive direction marked on the chip follows Ampere's law. 2. The device according to claim 1, wherein: One side of the groove of the U-shaped groove part is hinged with one side of the groove of the V-shaped groove part, and can be rotated in a direction perpendicular to the groove section; The other side of the groove of the U-shaped groove part and one side of the groove of the V-shaped groove part are connected by snaps. 3. The device according to claim 1, characterized in that: the device further comprises a computing unit; The linear displacement sensor is used to collect the linear displacement of the sensor after the device is put into the energized wire to be tested; the output end of the linear displacement sensor is connected to the input end of the computing unit; The tunnel magnetoresistance chip is used for collecting the analog differential signal affected by the magnetic field strength; the output end of the tunnel magnetoresistance chip is connected with the input end of the computing unit; The calculation unit is configured to calculate and obtain the current value of the energized wire to be tested according to the linear displacement amount and the analog differential signal. 4. The device according to claim 3, wherein: The calculation unit is configured to calculate and obtain the magnetic field strength according to the received analog differential signal; The calculation unit is configured to calculate and obtain the distance between the tunnel magnetoresistive chip and the center of the wire according to the received linear displacement; The calculation unit is configured to calculate and obtain the current value of the conducting wire to be tested according to the magnetic field strength and the distance between the tunnel magnetoresistive chip and the center of the wire. 5. The device according to claim 1, wherein the tunnel magnetoresistive chip is disposed on top of the linear displacement sensor, comprising: A magnetic sensitive probe is set on the top of the linear displacement sensor; The tunnel magnetoresistive chip is mounted on the PCB board and packaged inside the magneto-sensitive probe to ensure that the tunnel magnetoresistive chip is perpendicular to the symmetry axis. 6. The device according to claim 2, wherein: The V-shaped groove part and the surface of the U-shaped groove part are each provided with a level; the two levels are parallel to each other when the V-shaped groove part and the U-shaped groove part are placed opposite each other; An elastic buffer material is provided on the contact surfaces of the V-shaped groove part and the U-shaped groove part when they are placed oppositely; The buckle connected with the V-shaped groove part and the U-shaped groove part includes an adjustable and elastic locking part; Before measuring, adjust the indication of the two levels to keep the same by adjusting the locking part. 7 . The device according to claim 5 , wherein the material of the magnetic sensitive probe comprises flame-retardant plastic. 8 . 8 . The device according to claim 1 , wherein the linear displacement sensor is a sliding resistance type linear displacement sensor. 9 .

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