CN111650416A - Closed-loop AC/DC current sensor - Google Patents
Closed-loop AC/DC current sensor Download PDFInfo
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- CN111650416A CN111650416A CN202010490934.3A CN202010490934A CN111650416A CN 111650416 A CN111650416 A CN 111650416A CN 202010490934 A CN202010490934 A CN 202010490934A CN 111650416 A CN111650416 A CN 111650416A
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- operational amplifier
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- current sensor
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- 239000003990 capacitor Substances 0.000 claims description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 12
- 230000005389 magnetism Effects 0.000 abstract description 4
- 239000000463 material Substances 0.000 abstract description 4
- 238000009434 installation Methods 0.000 abstract description 2
- 238000005259 measurement Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
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- 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
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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
-
- 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
Closed-loop AC/DC current sensor, comprising: a magnetic sensing chip and a planar coil; the magnetic sensing chip is arranged in the center of the planar coil, and the magnetic sensing direction of the magnetic sensing chip is perpendicular to the plane of the planar antenna. The planar coil is adopted to replace a secondary coil wound on an iron core in the traditional current sensor for negative feedback, the iron core is not required to be used as a magnetism gathering material, the cost, the size and the weight of the sensor can be reduced to a great extent, the miniature and light-weight design of the current sensor can be realized by using the planar coil and the magnetic sensing chip, and the planar coil has the advantages of convenience in installation and low price.
Description
Technical Field
The invention belongs to the technical field of current measurement, and particularly relates to a closed-loop type alternating current and direct current sensor.
Background
The closed-loop current sensor has high measurement accuracy and use reliability, and is widely used in the field of alternating current and direct current measurement. The feedback compensation mode of the closed-loop current sensor mainly comprises a magnetic modulation mode and a magnetic sensing chip mode, and the feedback compensation mode structurally comprises the steps that an iron core (magnetic gathering material) is used for gathering magnetism to be measured, an electronic circuit or a Hall chip is used for modulating and demodulating a magnetic field in the iron core, then a signal processing unit at the later stage is used for processing the magnetic field, and then a feedback coil wound on the iron core is used for completing negative feedback, so that high-precision measurement is achieved. The iron core is used as a magnetism gathering material in the traditional closed-loop current sensor, the enameled wire is wound on the periphery of the iron core and serves as a feedback coil, the cost of the iron core and the enameled wire is high, generally, the iron core and the enameled wire can account for 1/2-2/3 of the cost of the whole sensor, the cost of the sensor is also high, the size and the weight of the iron core and the enameled wire are large, and the small-size and light-weight design of the current sensor cannot be achieved.
Disclosure of Invention
The invention aims to provide a closed loop type alternating current and direct current sensor which is low in cost, small in size and light in weight.
In order to achieve the purpose, the invention adopts the following technical solutions:
closed-loop AC/DC current sensor, comprising: a magnetic sensing chip and a planar coil; the magnetic sensing chip is arranged in the center of the planar coil, and the magnetic sensing direction of the magnetic sensing chip is perpendicular to the plane of the planar antenna.
Further, the planar coil is a planar PCB coil and comprises a circuit board, the planar coil is arranged on the circuit board, a chip mounting groove is formed in the circuit board and located in the center of the planar antenna, and the magnetic sensing chip is arranged in the chip mounting groove.
Further, the planar coil is of a single-arm spiral structure.
Further, the central line of the magnetic sensing chip is located on the plane of the planar coil.
Further, the magnetic sensing chip is a TMR chip.
The device further comprises a signal processing unit, wherein the signal processing unit comprises a signal acquisition circuit, a signal processing circuit, a feedback circuit and an output circuit; the input end of the signal acquisition circuit is connected with the output end of the magnetic sensing chip, the input end of the signal processing circuit is connected with the output end of the signal acquisition circuit, the input end of the feedback circuit is connected with the output end of the signal processing circuit, the output end of the feedback processing circuit is connected with the input end of the planar coil, and the output end of the planar coil is connected with the input end of the output circuit.
Furthermore, the signal acquisition circuit comprises a first operational amplifier, a first pin of an output port of the magnetic sensing chip is connected with an inverting input end of the first operational amplifier, a second pin is connected with a non-inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is connected with an output end of the first operational amplifier, the non-inverting input end of the first operational amplifier is grounded, and the output end of the first operational amplifier is connected with an input end of the signal processing circuit.
Furthermore, the signal processing circuit comprises a second operational amplifier, wherein the non-inverting input end of the second operational amplifier is connected with the output end of the signal acquisition circuit, the inverting input end of the second operational amplifier is grounded and is simultaneously connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the input end of the feedback circuit.
Further, the feedback circuit comprises a third operational amplifier, an inverting input end of the third operational amplifier is connected with the output end of the signal processing circuit and the output end of the third operational amplifier, a non-inverting input end of the third operational amplifier is grounded, and an output end of the third operational amplifier is connected with the input end of the planar coil.
Furthermore, the inverting input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier via a feedback resistor and a capacitor.
Furthermore, the output circuit comprises a secondary resistor, one end of the secondary resistor is connected with the output end of the planar coil, and the other end of the secondary resistor is grounded.
According to the technical scheme, the planar coil is adopted to replace a secondary coil wound on an iron core in the traditional current sensor for negative feedback, the iron core is not required to be used as a magnetism gathering material, the cost, the size and the weight of the sensor can be reduced to a great extent, the miniature and light-weight design of the current sensor can be realized by using the planar coil and the magnetic sensing chip, and the current sensor has the advantages of convenience in installation and low price.
Drawings
In order to illustrate the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained by those skilled in the art without inventive effort.
FIG. 1 is a schematic structural diagram of an embodiment of the present invention;
fig. 2 is a circuit diagram of a signal processing unit according to an embodiment of the invention.
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Detailed Description
The invention will be described in detail below with reference to the accompanying drawings, wherein for the purpose of illustrating embodiments of the invention, the drawings showing the structure of the device are not to scale but are partly enlarged, and the schematic drawings are only examples, and should not be construed as limiting the scope of the invention. It is to be noted, however, that the drawings are designed in a simplified form and are not to scale, but rather are to be construed in an attempt to more clearly and concisely illustrate embodiments of the present invention.
As shown in fig. 1, the closed loop type ac/dc current sensor of the present invention includes a magnetic sensing chip 1, a planar coil 2, and a signal processing unit, wherein the planar coil 2 is used as a feedback coil of the current sensor. The magnetic sensor chip 1 of the present embodiment is a TMR chip. The planar coil 2 can be etched on the circuit board by adopting a printed circuit board manufacturing process, namely, the planar coil 2 is a planar PCB coil. The planar coil 2 of the present embodiment is formed on the circuit board 2-1, the planar coil 2 may be a planar spiral coil, the planar coil 2 of the present embodiment is a one-arm circular spiral structure, and in other embodiments, the planar coil may also be a rectangular spiral structure or other planar spiral structures. A chip mounting groove 2-1a is arranged on the circuit board 2-1, the chip mounting groove 2-1a is positioned at the center of the planar coil 2, the magnetic sensing chip 1 is arranged at the position of the chip mounting groove 2-1a, and the magnetic sensing direction of the magnetic sensing chip 1 is vertical to the plane of the planar coil 2. The performance of the sensor is reduced when the center line of the magnetic sensing chip 1 is far away from the plane of the coil, so it is preferable to arrange the magnetic sensing chip 1 such that the center line of the magnetic sensing chip 1 is on the plane of the planar coil 2, so as to obtain better detection effect.
The output end of the magnetic sensing chip 1 is connected to a signal processing unit, as shown in fig. 2, the signal processing unit of this embodiment includes a signal acquisition circuit a, a signal processing circuit B, a feedback circuit C, and an output circuit D. The input end of the signal acquisition circuit A is connected with the output end of the magnetic sensing chip 1, the input end of the signal processing circuit B is connected with the output end of the signal acquisition circuit A, the input end of the feedback circuit C is connected with the output end of the signal processing circuit B, the output end of the feedback processing circuit C is connected with the input end of the planar coil 2, the output end of the planar coil 2 is connected with the input end of the output circuit D, and the output circuit D outputs a final detection value.
The signal acquisition circuit A is used for acquiring voltage signals modulated and demodulated by the TMR chip (the magnetic sensing chip 1). As shown in fig. 2, the signal acquisition circuit a of this embodiment includes a first operational amplifier U1A, of two pins of an output port P8 of the magnetic sensing chip 1, the first pin 1 is connected to an inverting input terminal of the first operational amplifier U1A through a resistor R1, the second pin 2 is connected to a non-inverting input terminal of the first operational amplifier U1A through a resistor R2, the inverting input terminal of the first operational amplifier U1A is connected to an output terminal of the first operational amplifier U1A through a feedback resistor R3, the non-inverting input terminal of the first operational amplifier U1A is connected to the ground through a ground resistor R4, and the output terminal of the first operational amplifier U1A is connected to the input terminal of the signal processing circuit B.
The signal processing circuit B is used for amplifying the signals acquired by the signal acquisition circuit A. As shown in fig. 2, the signal processing circuit B of this embodiment includes a second operational amplifier U2B, a non-inverting input terminal of the second operational amplifier U2B is connected to the output terminal of the signal acquisition circuit a via a resistor R6, an inverting input terminal of the second operational amplifier U2B is connected to ground via a ground resistor R8, and is connected to the output terminal of the second operational amplifier U2B via a feedback resistor R7, and an output terminal of the second operational amplifier U2B is connected to the input terminal of the feedback circuit C.
The feedback circuit C is configured to output the signal processed by the signal processing circuit B to the planar coil 2. As shown in fig. 2, the feedback circuit C includes a third operational amplifier U1C, an inverting input terminal of the third operational amplifier U1C is connected to the output terminal of the signal processing circuit B through a resistor R9, and is connected to the output terminal of the third operational amplifier U1C through a feedback resistor R11 and a capacitor C1, a non-inverting input terminal thereof is grounded through a grounding resistor R10, and an output terminal of the third operational amplifier U1C is connected to the input terminal of the planar coil 2.
The output circuit D includes a secondary resistor R12, one end of the secondary resistor R12 is connected to the output terminal of the planar coil 2(L1), and the other end is grounded, and the detection value of the current sensor is output by measuring the voltage of the secondary resistor R12.
The measurement process of the current sensor of the present invention is described below with reference to fig. 1:
a reserved wire clamping groove is formed in a sensor housing (not shown) and used for placing a current wire to be measured, as shown in fig. 1, the current wire 100 to be measured surrounds the periphery of the planar coil 2, when current flows in the current wire 100 to be measured, the magnetic sensing chip 1 can sense a magnetic field generated by the current passing through the current wire 100 to be measured and send a detected signal to the signal processing unit, the signal processing unit collects, amplifies and the like the signal sent by the magnetic sensing chip 1 and then feeds the signal back to the planar coil 2, and when zero magnetic flux is reached, the voltage value of a secondary resistor in the output circuit is measured, so that the current value to be measured can be obtained.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention.
Claims (11)
1. Closed-loop AC/DC current sensor, characterized in that includes: a magnetic sensing chip and a planar coil; the magnetic sensing chip is arranged in the center of the planar coil, and the magnetic sensing direction of the magnetic sensing chip is perpendicular to the plane of the planar antenna.
2. The closed loop ac-dc current sensor of claim 1, wherein: the planar coil is a planar PCB coil and comprises a circuit board, the planar coil is arranged on the circuit board, a chip mounting groove is formed in the circuit board and located in the center of the planar antenna, and the magnetic sensing chip is arranged in the chip mounting groove.
3. The closed loop ac-dc current sensor of claim 1, wherein: the planar coil is a planar spiral coil.
4. The closed loop ac-dc current sensor of claim 1, wherein: the central line of the magnetic sensing chip is positioned on the plane of the planar coil.
5. The closed loop ac-dc current sensor of claim 1, wherein: the magnetic sensing chip is a TMR chip.
6. The closed loop ac-dc current sensor of claim 1, wherein: the signal processing unit comprises a signal acquisition circuit, a signal processing circuit, a feedback circuit and an output circuit;
the input end of the signal acquisition circuit is connected with the output end of the magnetic sensing chip, the input end of the signal processing circuit is connected with the output end of the signal acquisition circuit, the input end of the feedback circuit is connected with the output end of the signal processing circuit, the output end of the feedback processing circuit is connected with the input end of the planar coil, and the output end of the planar coil is connected with the input end of the output circuit.
7. The closed loop ac-dc current sensor of claim 6, wherein: the signal acquisition circuit comprises a first operational amplifier, a first pin of an output port of the magnetic sensing chip is connected with an inverting input end of the first operational amplifier, a second pin of the output port of the magnetic sensing chip is connected with a non-inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is connected with an output end of the first operational amplifier, the non-inverting input end of the first operational amplifier is grounded, and the output end of the first operational amplifier is connected with an input end of the signal processing circuit.
8. The closed loop ac-dc current sensor of claim 6, wherein: the signal processing circuit comprises a second operational amplifier, the non-inverting input end of the second operational amplifier is connected with the output end of the signal acquisition circuit, the inverting input end of the second operational amplifier is grounded and is simultaneously connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the input end of the feedback circuit.
9. The closed loop ac-dc current sensor of claim 6, wherein: the feedback circuit comprises a third operational amplifier, the inverting input end of the third operational amplifier is connected with the output end of the signal processing circuit and is connected with the output end of the third operational amplifier, the non-inverting input end of the third operational amplifier is grounded, and the output end of the third operational amplifier is connected with the input end of the planar coil.
10. The closed loop ac-dc current sensor of claim 9, wherein: and the inverting input end of the third operational amplifier is connected with the output end of the third operational amplifier through a feedback resistor and a capacitor.
11. The closed loop ac-dc current sensor of claim 6, wherein: the output circuit comprises a secondary resistor, one end of the secondary resistor is connected with the output end of the planar coil, and the other end of the secondary resistor is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010490934.3A CN111650416A (en) | 2020-06-02 | 2020-06-02 | Closed-loop AC/DC current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010490934.3A CN111650416A (en) | 2020-06-02 | 2020-06-02 | Closed-loop AC/DC current sensor |
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| Publication Number | Publication Date |
|---|---|
| CN111650416A true CN111650416A (en) | 2020-09-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010490934.3A Pending CN111650416A (en) | 2020-06-02 | 2020-06-02 | Closed-loop AC/DC current sensor |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113049868A (en) * | 2021-03-10 | 2021-06-29 | 优利德科技(中国)股份有限公司 | Alternating current and direct current measuring device and measuring method |
| EP4538719A1 (en) * | 2023-10-10 | 2025-04-16 | ABB Schweiz AG | Current detection device for electrical installations |
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| JP2002333456A (en) * | 2001-05-08 | 2002-11-22 | Mitsubishi Electric Corp | Current sensor |
| CN101677031A (en) * | 2008-09-19 | 2010-03-24 | 周有庆 | Straight wire PCB plane spiral coil primary current sensor |
| CN105866515A (en) * | 2016-06-15 | 2016-08-17 | 成都芯进电子有限公司 | Current sensor |
| CN208109914U (en) * | 2018-04-16 | 2018-11-16 | 潍坊医学院 | Ring-shaped current sensor |
| CN109358221A (en) * | 2018-12-11 | 2019-02-19 | 北京麦格智能科技有限公司 | A kind of low magnetic hysteresis current sensor |
| CN110865226A (en) * | 2019-12-13 | 2020-03-06 | 珠海多创科技有限公司 | Closed loop current sensor |
| CN212723050U (en) * | 2020-06-02 | 2021-03-16 | 珠海多创科技有限公司 | Closed loop type AC/DC current sensor |
-
2020
- 2020-06-02 CN CN202010490934.3A patent/CN111650416A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002333456A (en) * | 2001-05-08 | 2002-11-22 | Mitsubishi Electric Corp | Current sensor |
| CN101677031A (en) * | 2008-09-19 | 2010-03-24 | 周有庆 | Straight wire PCB plane spiral coil primary current sensor |
| CN105866515A (en) * | 2016-06-15 | 2016-08-17 | 成都芯进电子有限公司 | Current sensor |
| CN208109914U (en) * | 2018-04-16 | 2018-11-16 | 潍坊医学院 | Ring-shaped current sensor |
| CN109358221A (en) * | 2018-12-11 | 2019-02-19 | 北京麦格智能科技有限公司 | A kind of low magnetic hysteresis current sensor |
| CN110865226A (en) * | 2019-12-13 | 2020-03-06 | 珠海多创科技有限公司 | Closed loop current sensor |
| CN212723050U (en) * | 2020-06-02 | 2021-03-16 | 珠海多创科技有限公司 | Closed loop type AC/DC current sensor |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113049868A (en) * | 2021-03-10 | 2021-06-29 | 优利德科技(中国)股份有限公司 | Alternating current and direct current measuring device and measuring method |
| EP4538719A1 (en) * | 2023-10-10 | 2025-04-16 | ABB Schweiz AG | Current detection device for electrical installations |
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