CN112083211A - Current sensor - Google Patents
Current sensorDownload PDFInfo
- Publication number
- CN112083211A CN112083211ACN202010983520.4ACN202010983520ACN112083211ACN 112083211 ACN112083211 ACN 112083211ACN 202010983520 ACN202010983520 ACN 202010983520ACN 112083211 ACN112083211 ACN 112083211A
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- current sensor
- magnetoresistive element
- element group
- current
- magneto
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- 230000001939inductive effectEffects0.000claimsdescription6
- 230000035945sensitivityEffects0.000abstractdescription7
- 230000009286beneficial effectEffects0.000abstractdescription4
- 239000010409thin filmSubstances0.000description5
- 230000005294ferromagnetic effectEffects0.000description4
- 230000005381magnetic domainEffects0.000description3
- 238000000151depositionMethods0.000description2
- 239000010408filmSubstances0.000description2
- 230000005415magnetizationEffects0.000description2
- 238000005259measurementMethods0.000description2
- 238000000034methodMethods0.000description2
- 229910001030Iron–nickel alloyInorganic materials0.000description1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-NSiliconChemical compound[Si]XUIMIQQOPSSXEZ-UHFFFAOYSA-N0.000description1
- 230000007423decreaseEffects0.000description1
- 230000007547defectEffects0.000description1
- 230000008021depositionEffects0.000description1
- 238000010586diagramMethods0.000description1
- 238000009434installationMethods0.000description1
- 239000000696magnetic materialSubstances0.000description1
- 239000000463materialSubstances0.000description1
- 239000002245particleSubstances0.000description1
- 229910001404rare earth metal oxideInorganic materials0.000description1
- 229910052710siliconInorganic materials0.000description1
- 239000010703siliconSubstances0.000description1
- 239000000758substrateSubstances0.000description1
- 229910002070thin film alloyInorganic materials0.000description1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
- G01R15/205—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using magneto-resistance devices, e.g. field plates
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a current sensor.
Background
Traditional hall current sensor realizes based on the magnetic core, but the magnetic core has seriously influenced the miniaturization of chip owing to the volume is too big, and the magnetic core has defects such as hysteresis lag and nonlinearity simultaneously, consequently, in 50A current range, no magnetic core product has replaced current magnetic core open loop current sensor gradually.
The traditional Hall current sensor without the magnetic core adopts a factory pre-calibration mode for eliminating temperature drifts such as sensitivity, and the method has high test cost, and can be influenced by stress caused by an external environment in the actual installation and use process of the current sensor, so that the measurement precision of the current sensor is influenced. And because of the influence of the low sensitivity of the Hall sensor, the traditional current sensor without the magnetic core has difficulty in realizing the current measurement of more than 50A, and the performance is greatly limited.
Disclosure of Invention
According to the above problems in the prior art, a circuit sensor chip is provided, which not only eliminates temperature drift such as sensitivity, but also increases the range of the current sensor by setting a differential gradient closed-loop mode, and reduces the size and cost while maintaining the high performance of the current sensor.
The technical scheme specifically comprises the following steps:
a current sensor for measuring a current value of a current to be measured, comprising:
the bus bar is used for flowing the current to be detected, the bus bar is of a U-shaped structure, the U-shaped structure comprises a first arm and a second arm, and the first arm and the second arm are two parallel edges of the U-shaped structure respectively;
the first element group is positioned on the first arm and used for inducing a magnetic field generated by the current to be detected, the first element group comprises a plurality of magneto-resistance elements, the magneto-resistance elements are connected in series, and a first voltage acquisition point is arranged at the connection position of the magneto-resistance elements;
the second element group is positioned on the second arm and used for inducing a magnetic field generated by the current to be detected, the second element group comprises the magneto-resistance elements which are the same as the first element group in number and are mutually connected in series, and a second voltage acquisition point is arranged at a position corresponding to the first voltage acquisition point;
the plurality of compensation coils are respectively and correspondingly arranged on the upper surface of the magneto-resistance element and used for generating a compensation magnetic field;
the input end of the operational amplifier is respectively connected with the first voltage acquisition point and the second voltage acquisition point, and the plurality of compensation coils are mutually connected in series and connected with the output end of the operational amplifier.
Preferably, the first element group and the second element group are connected in parallel with each other and are connected to an external power supply.
Preferably, the current sensor further comprises a SET/RESET coil for resetting the magnetoresistive element.
Preferably, wherein the magnetoresistive element is an anisotropic magnetoresistive element.
Preferably, wherein the compensation coil is a double-layer compensation coil.
Preferably, the current sensor includes a voltage input terminal, one end of the voltage input terminal is connected to the first element group and the second element group, and the other end is connected to the external power supply.
Preferably, a groove is arranged on the bus bar, and the magneto-resistive element is arranged in the groove.
Preferably, the current sensor includes a resistor, one end of the resistor is connected to the compensation coil, and the other end of the resistor is grounded.
Preferably, the current sensor includes a signal output terminal, and the signal output terminal is disposed between the connection point of the resistor and the compensation coil.
Preferably, wherein the first element group includes a first magnetoresistive element and a second magnetoresistive element, and the second element group includes a third magnetoresistive element and a fourth magnetoresistive element;
the first voltage collection point is located between the first magnetoresistive element and the second magnetoresistive element;
the second voltage collection point is located between the third magnetoresistive element and the fourth magnetoresistive element.
The beneficial effects of the above technical scheme are that:
the circuit sensor chip eliminates temperature drift such as sensitivity and the like through setting of a differential gradient closed-loop mode, increases the measuring range of the current sensor, reduces the size while keeping high performance of the current sensor, and reduces the cost.
Drawings
FIG. 1 is a circuit diagram of a current sensor according to a preferred embodiment of the present invention;
the above reference numerals denote descriptions:
the circuit comprises a bus bar (1), a first arm (10), a second arm (11), a first magnetic resistance element (20), a second magnetic resistance element (21), a third magnetic resistance element (30), a fourth magnetic resistance element (31), a compensation coil (4), an operational amplifier (5), a SET/RESET coil (6) and a resistor (7).
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
A current sensor for measuring a current value of a current to be measured, as shown in fig. 1, comprising:
the bus bar 1 is used for flowing current to be measured, the bus bar 1 is of a U-shaped structure, the U-shaped structure comprises afirst arm 10 and asecond arm 11, and thefirst arm 10 and thesecond arm 11 are two parallel edges of the U-shaped structure respectively;
the first element group is positioned on thefirst arm 10 and used for inducing a magnetic field generated by current to be detected, the first element group comprises a plurality of magneto-resistance elements, the magneto-resistance elements are connected in series, and a first voltage acquisition point is arranged at the connection position of the magneto-resistance elements;
the second element group is positioned on thesecond arm 11 and used for inducing a magnetic field generated by current to be detected, the second element group comprises magneto-resistance elements which are the same as the first element group in number and are mutually connected in series, and a second voltage acquisition point is arranged at a position corresponding to the first voltage acquisition point;
a plurality ofcompensation coils 4 respectively and correspondingly arranged on the upper surface of the magneto-resistance element and used for generating a compensation magnetic field;
the input end of the operational amplifier 5 is respectively connected with the first voltage acquisition point and the second voltage acquisition point, and the plurality ofcompensation coils 4 are mutually connected in series and connected with the output end of the operational amplifier 5.
In a preferred embodiment, in the present embodiment, when a current to be measured flows through the bus bar 1, a magnetic field is generated around the bus bar 1, and the magnitude of the magnetic field is proportional to the magnitude of the current flowing through the bus bar 1. The magnetic resistance element is the resistance of a thin film alloy capable of sensing a magnetic field, and the resistance value of the magnetic resistance element can change obviously when the magnetic resistance element senses the magnetic field. The magnetoresistive elements can be broadly classified by function into normal magnetoresistance (OMR) of magnetic materials directly induced by a magnetic field, Anisotropic Magnetoresistance (AMR) associated with technical magnetization, Colossal Magnetoresistance (CMR) in a doped rare earth oxide, Giant Magnetoresistance (GMR) peculiar to magnetic multilayer films and particle films, Tunnel Magnetoresistance (TMR), and the like. The sensor is most sensitive when the current direction is parallel to the magnetization direction.
In the preferred embodiment of the present invention, the first device group and the second device group are connected in parallel and are connected to an external power source.
Specifically, in the present embodiment, the first element group and the second element group together form a wheatstone bridge.
In a preferred embodiment of the invention the current sensor further comprises a SET/RESET coil 6 for resetting the magnetoresistive element.
Specifically, in the present embodiment, the SET/RESET coil 6 functions to RESET the magnetoresistive element, so that the magnetoresistive sensor always operates in a high-sensitivity state. Under the impact influence of some larger external magnetic fields, the magnetic domains of the ferromagnetic thin film materials forming the sensor can present a random orientation state, which can seriously reduce the sensitivity of the magneto-resistance element, the SET/RESET coil 6 is equivalent to a ferromagnetic resistor, when an impact current passes through the ferromagnetic resistor, an 'internal' magnetic field along the sensitive direction of the magneto-resistance element can be generated, under the condition that an impact circuit is large enough, the 'internal' magnetic field large enough can enable the magnetic domains of the sensor to be arranged orderly along the sensitive direction, so that the magneto-resistance element returns to an initial state, and the sensing magnetic field in the state can have sensitive and most accurate output signals.
In this embodiment, the SET/RESET coil 6 is arranged to periodically RESET the current sensor so that the magnetic domain always senses the external magnetic field from an initial state, which can make the measured data accurately reflect the changing magnetic field when measuring the changing magnetic field.
In a preferred embodiment of the invention, the magnetoresistive element is an anisotropic magnetoresistive element.
Specifically, in this embodiment, the anisotropic magnetoresistive element is formed by depositing an iron-nickel alloy thin film on a silicon substrate, and the thin film is arranged in a strip form during deposition to form a planar linear array to increase the area of the magnetoresistive sensing magnetic field. When an external magnetic field is applied to the ferromagnetic thin film, the domains rotate, changing the spatial orientation, which causes the apparent resistance of the linear array of thin film strips to change, specifically, the resistance on the opposing arms of the bridge increases, while the resistance on the other opposing arms decreases, reflecting the magnitude of the external magnetic field on the change in the voltage output of the bridge. Specifically, in this embodiment, the first element group and the second element group jointly form a bridge, and the first element group and the second element group respectively form two bridge arms of the bridge.
In the preferred embodiment of the present invention, thecompensation coil 4 is a double-layer compensation coil 4.
Specifically, in this embodiment, increasing the magnetic field generated by the unit compensation current is beneficial to increasing the signal-to-noise ratio or reducing the power consumption in the same dynamic range, so that thecompensation coil 4 in this embodiment adopts the double-layer compensation coil 4 mode, and a larger compensation magnetic field generated by the unit current can be realized.
In a preferred embodiment of the present invention, the current sensor includes a voltage input terminal, one end of the voltage input terminal is connected to the first element group and the second element group, and the other end is connected to an external power source.
In a preferred embodiment of the present invention, the bus bar 1 is provided with a groove, and the magnetoresistive element is disposed in the groove.
In the preferred embodiment of the present invention, the current sensor includes a resistor 7, one end of the resistor 7 is connected to thecompensation coil 4, and the other end of the resistor 7 is grounded.
In the preferred embodiment of the present invention, the current sensor includes a signal output terminal VoutSignal output terminal VouIs arranged between the resistor 7 and the connection point of thecompensation coil 4.
Specifically, in the present embodiment, the signal output terminal VouThe output voltage signal is used to represent the magnitude of the current to be measured flowing through the bus bar 1.
In a preferred embodiment of the present invention, the first element group includes afirst magnetoresistive element 20 and asecond magnetoresistive element 21, and the second element group includes a thirdmagnetoresistive element 30 and afourth magnetoresistive element 31;
the first voltage collection point is located between thefirst magnetoresistive element 20 and thesecond magnetoresistive element 21;
the second voltage collection point is located between thirdmagnetoresistive element 30 and fourthmagnetoresistive element 31.
The beneficial effects of the above technical scheme are that:
the circuit sensor chip eliminates temperature drift such as sensitivity and the like through setting of a differential gradient closed-loop mode, increases the measuring range of the current sensor, reduces the size while keeping high performance of the current sensor, and reduces the cost.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (10)
1. A current sensor for measuring a current value of a current to be measured, comprising:
the bus bar is used for flowing the current to be detected, the bus bar is of a U-shaped structure, the U-shaped structure comprises a first arm and a second arm, and the first arm and the second arm are two parallel edges of the U-shaped structure respectively;
the first element group is positioned on the first arm and used for inducing a magnetic field generated by the current to be detected, the first element group comprises a plurality of magneto-resistance elements, the magneto-resistance elements are connected in series, and a first voltage acquisition point is arranged at the connection position of the magneto-resistance elements;
the second element group is positioned on the second arm and used for inducing a magnetic field generated by the current to be detected, the second element group comprises the magneto-resistance elements which are the same as the first element group in number and are mutually connected in series, and a second voltage acquisition point is arranged at a position corresponding to the first voltage acquisition point;
the plurality of compensation coils are respectively and correspondingly arranged on the upper surface of the magneto-resistance element and used for generating a compensation magnetic field;
the input end of the operational amplifier is respectively connected with the first voltage acquisition point and the second voltage acquisition point, and the plurality of compensation coils are mutually connected in series and connected with the output end of the operational amplifier.
2. The current sensor of claim 1, wherein the first set of elements and the second set of elements are connected in parallel to each other and to an external power source.
3. The current sensor of claim 1, further comprising a SET/RESET coil for resetting the magnetoresistive element.
4. The current sensor of claim 1, wherein the magnetoresistive element is an anisotropic magnetoresistive element.
5. The current sensor of claim 1, wherein the bucking coil is a double layer bucking coil.
6. The current sensor of claim 1, wherein the current sensor includes a voltage input terminal, one end of the voltage input terminal is connected to the first element group and the second element group, and the other end is connected to the external power source.
7. The current sensor of claim 1, wherein the buss bar is provided with a recess, the magnetoresistive element being disposed within the recess.
8. The current sensor of claim 1, wherein the current sensor comprises a resistor, one end of the resistor is connected to the compensation coil, and the other end of the resistor is grounded.
9. The current sensor of claim 8, wherein the current sensor includes a signal output disposed between the junction of the resistor and the compensation coil.
10. The current sensor according to claim 1, wherein the first element group includes a first magnetoresistive element and a second magnetoresistive element, and the second element group includes a third magnetoresistive element and a fourth magnetoresistive element;
the first voltage collection point is located between the first magnetoresistive element and the second magnetoresistive element;
the second voltage collection point is located between the third magnetoresistive element and the fourth magnetoresistive element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010983520.4ACN112083211A (en) | 2020-09-17 | 2020-09-17 | Current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010983520.4ACN112083211A (en) | 2020-09-17 | 2020-09-17 | Current sensor |
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|---|---|
| CN112083211Atrue CN112083211A (en) | 2020-12-15 |
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| CN202010983520.4APendingCN112083211A (en) | 2020-09-17 | 2020-09-17 | Current sensor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113640713A (en)* | 2021-10-13 | 2021-11-12 | 苏州纳芯微电子股份有限公司 | Magnetic field sensing element compensation circuit and compensation method |
| CN114217114A (en)* | 2021-12-21 | 2022-03-22 | 江苏多维科技有限公司 | Current sensor |
| CN114966160A (en)* | 2022-07-29 | 2022-08-30 | 浙江大学 | Laminated busbar and power device current detection device based on tunnel magnetoresistance |
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- 2020
- 2020-09-17CNCN202010983520.4Apatent/CN112083211A/enactivePending
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| Title |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113640713A (en)* | 2021-10-13 | 2021-11-12 | 苏州纳芯微电子股份有限公司 | Magnetic field sensing element compensation circuit and compensation method |
| CN114217114A (en)* | 2021-12-21 | 2022-03-22 | 江苏多维科技有限公司 | Current sensor |
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| CN114966160A (en)* | 2022-07-29 | 2022-08-30 | 浙江大学 | Laminated busbar and power device current detection device based on tunnel magnetoresistance |
| CN114966160B (en)* | 2022-07-29 | 2022-10-25 | 浙江大学 | Laminated busbar and power device current detection device based on tunnel magnetoresistance |
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| CB02 | Change of applicant information | Address after:Room 307, 3rd floor, 1328 Dingxi Road, Changning District, Shanghai 200050 Applicant after:Shanghai Sirui Technology Co.,Ltd. Address before:Floor 1, building 2, No. 235, Chengbei Road, Jiading District, Shanghai, 201800 Applicant before:QST Corp. | |
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| RJ01 | Rejection of invention patent application after publication | Application publication date:20201215 |