CN111521857B - Multi-conductor current measuring system based on TMR tunnel magnetic resistance - Google Patents
Multi-conductor current measuring system based on TMR tunnel magnetic resistance Download PDFInfo
- Publication number
- CN111521857B CN111521857B CN202010366631.0A CN202010366631A CN111521857B CN 111521857 B CN111521857 B CN 111521857B CN 202010366631 A CN202010366631 A CN 202010366631A CN 111521857 B CN111521857 B CN 111521857B
- Authority
- CN
- China
- Prior art keywords
- tmr
- chip
- current
- conductor
- chips
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Classifications
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention provides a multi-conductor current measuring system based on TMR tunnel magnetic resistance, which comprises a TMR chip array and a processing unit connected with the output end of the TMR chip array; the TMR chip array comprises m TMR chips, wherein the m TMR chips are all positioned under the axial center line of a main conductor to be tested, the m TMR chips are sequentially arranged from top to bottom, adjacent chips are arranged at equal intervals, the distance between the TMR chip with the minimum distance from the main conductor to be tested and the main conductor to be tested is equal to the interval between the adjacent chips, and the processing unit obtains the current of the conductor to be tested from the main conductor according to a voltage signal output by the TMR chips; the method can be used for accurately measuring the current of conductors with different specifications, different purposes and different current grades of the high-voltage direct-current transmission system, can eliminate the influence of multiple conductors on measurement, and provides a powerful guarantee for the stable operation of the high-voltage direct-current transmission system.
Description
Technical Field
The invention relates to a current measuring system, in particular to a multi-conductor current measuring system based on TMR tunnel magnetic resistance.
Background
With the continuous advance of the construction of a high voltage direct current transmission system (HVDC), in order to ensure the stable operation of the HVDC transmission system, current parameters of each link of the HVDC transmission system need to be accurately monitored in real time. Because there are conductors of various specifications in the high-voltage direct-current transmission system, and the current grades carried by the conductors of different specifications and different purposes are also greatly different, inductive measurement is generally adopted for measuring the conductor current of the high-voltage transmission system, but because there are numerous conductors in the transmission line, each conductor can generate an induction magnetic field at a measuring point and superpose, thereby causing serious influence on the result of the inductive measurement, and the accuracy is low.
Disclosure of Invention
In view of this, the present invention provides a multi-conductor current measurement system based on TMR tunnel magnetoresistance, which can perform accurate current measurement for conductors of different specifications, different applications and different current levels of a high voltage direct current transmission system, eliminate mutual influence between the conductors, and provide a powerful guarantee for stable operation of the high voltage direct current transmission system.
The invention provides a multi-conductor current measuring system based on TMR tunnel magnetic resistance, which comprises a TMR chip array and a processing unit connected with the output end of the TMR chip array;
the TMR chip array comprises m TMR chips, wherein the m TMR chips are all located under the axial center line of a main tested conductor, the m TMR chips are sequentially arranged from top to bottom, adjacent chips are arranged at equal intervals, the distance between the TMR chip with the minimum distance from the main tested conductor and the main tested conductor is equal to the distance between the adjacent chips, and the processing unit obtains the current of the tested conductor from the multiple conductors according to the voltage signal output by the TMR chips.
Further, the processing unit comprises a differential signal conversion circuit, a bias processing circuit and a microcontroller;
the input end of the differential signal conversion circuit is connected with the output end of the TMR chip and is used for converting the differential signal output by the TMR chip into a single-ended signal and outputting the single-ended signal;
the input end of the bias processing circuit is connected with the output end of the differential signal conversion circuit and used for converting the single-ended signal into a positive voltage signal and inputting the positive voltage signal into the microcontroller;
and the microcontroller is used for receiving the positive voltage signal output by the bias processing circuit and outputting the current value of the tested conductor according to the positive voltage signal.
Further, the microcontroller obtains the current of the tested conductor according to the following method:
performing piecewise linear approximation on an output voltage curve of the TMR chip to obtain a piecewise linear function U of the TMR output voltage curve U and the magnetic induction intensity, wherein s is the slope of the piecewise function, B is the magnetic induction intensity component in the sensitive direction of the chip, and c is the intercept of the piecewise function;
constructing a model of the measured current and magnetic induction intensity and TMR chip output voltage:
wherein n represents the number of conductors, BijRepresents the magnetic induction intensity, s, generated by the unit current of the ith conductor in the sensitivity direction of the jth TMR chipiThe slope of the piecewise linear function, U, representing the ith TMR chip output voltageiIs the output voltage of the ith TMR chip, ciIntercept of piecewise linear function of output voltage of ith TMR chip, IiIs the current of the ith conductor, i ═ 1,2, …, n; j is 1,2,3, …, n; and discarding the output data of a plurality of chips when the number of conductors is less than that of the chips.
And substituting the chip output voltage into the model to obtain the final current value of the tested conductor.
Further, the processing circuit also comprises a display, and the display is in communication connection with the microcontroller.
Further, the microcontroller is a single chip microcomputer.
The invention has the beneficial effects that: by the method, accurate current measurement can be performed on conductors of different specifications, different purposes and different current grades of the high-voltage direct-current transmission system, mutual influence among the conductors can be eliminated, and powerful guarantee is provided for stable operation of the high-voltage direct-current transmission system.
Drawings
The invention is further described below with reference to the following figures and examples:
FIG. 1 is a schematic structural diagram of the present invention.
Fig. 2 is an electrical schematic of the present invention.
FIG. 3 is a schematic diagram of the nonlinearity of the TMR chip output function of the present invention.
FIG. 4 is a diagram illustrating a nonlinear function piecewise linear approximation method according to the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings, in which: in fig. 1, reference numeral 1 is m TMR chips, reference numeral 2 is a mounting bracket of the TMR chip, 3 is a PCB board carrying the TMR chip, 4 is a main conductor to be tested, and 5 is an interference conductor or other conductors to be tested existing in the same environment as the conductor to be tested.
The invention provides a multi-conductor current measuring system based on TMR tunnel magnetic resistance, which comprises a TMR chip array and a processing unit connected with the output end of the TMR chip array;
the TMR chip array comprises m TMR chips, wherein the m TMR chips are all positioned under the axial center line of a main conductor to be tested, the m TMR chips are sequentially arranged from top to bottom, adjacent chips are arranged at equal intervals, the distance between the TMR chip with the minimum distance from the main conductor to be tested and the main conductor to be tested is equal to the interval between the adjacent chips, and the processing unit obtains the current of the conductor to be tested from the main conductor according to a voltage signal output by the TMR chips; according to the invention, accurate current measurement can be carried out on conductors of different specifications, different purposes and different current grades of the high-voltage direct-current transmission system, the influence of multiple conductors on the measurement can be eliminated, and a powerful guarantee is provided for the stable operation of the high-voltage direct-current transmission system. The measuring method of the invention is as follows:
the TMR chip measures the space magnetic field at the position and outputs a corresponding voltage value; in order to reduce the current measurement error caused by chip output nonlinearity, the output voltage of the TMR chip is obtained by adopting a piecewise linear approximation method: as shown in fig. 3 and 4: obvious nonlinearity exists in the function of the output voltage U and the magnetic field intensity H of an external magnetic field in the sensitive direction of the chip, and the piecewise linear output function of the TMR chip is U ═ f (B), wherein B ═ mu ═ f (B)0H and B are magnetic induction intensity in the sensitive direction of the chip.
In this embodiment, the processing unit includes a differential signal conversion circuit, a bias processing circuit, and a microcontroller;
the input end of the differential signal conversion circuit is connected with the output end of the TMR chip and is used for converting the differential signal output by the TMR chip into a single-ended signal and outputting the single-ended signal;
the input end of the bias processing circuit is connected with the output end of the differential signal conversion circuit and used for converting the single-ended signal into a positive voltage signal and inputting the positive voltage signal into the microcontroller;
the microcontroller is used for receiving the positive voltage signal output by the bias processing circuit and outputting the current value of the detected conductor according to the positive voltage signal; specifically, the method comprises the following steps: the processing circuit further comprises a display, and the display is in communication connection with the microcontroller; the microcontroller is a single chip microcomputer.
In this embodiment, the microcontroller obtains the current of the conductor to be tested according to the following method:
performing piecewise linear approximation on an output voltage curve of the TMR chip to obtain a piecewise linear function U of the TMR output voltage curve U and the magnetic induction intensity, wherein s is the slope of the piecewise function, B is the magnetic induction intensity component in the sensitive direction of the chip, and c is the intercept of the piecewise function; based on the above, each TMR chip has a corresponding output function, i.e. U ═ f (b), which is a nonlinear function, and by this step, the current measurement error introduced by the output nonlinearity is reduced, and the stability of the output result is ensured, wherein, the output function of the TMR chip is as shown in fig. 3: in fig. 3, the solid line curve indicated by the mark 7 is the output function of the TMR chip, and the dashed line curve 6 is the linearization processing of the output function of the TMR chip, and it can be seen from the figure that after the linearization processing, the intercept and the slope are kept unchanged no matter what the output voltage of the TMR chip is, thereby causing large error, while in fig. 4, after the piecewise linear approximation is performed on the curve of the TMR chip output function, the curve of the output function is approximated by a plurality of straight line segments, which is close to the real output curve, thereby being able to ensure the accuracy of the measurement result; the output piecewise function slope s and intercept c of each TMR chip are determined as follows:
when the value of the voltage signal U output by the TMR chip is in (x)1，x2) When the interval curve is on, the slope s of the segmented output function of the TMR chip is F1(x) The slope of a line segment, and the intercept c is also the intercept of that line segment if the value of U is atIn (x)2，x3) When on the curve of the interval, the slope s is F2(x) The slope of the line segment, and the intercept c is also the intercept of the line segment; by analogy, the slope and intercept of the segmented output function of each TMR chip can be determined;
constructing a model of the measured current and magnetic induction intensity and TMR chip output voltage:
wherein n represents the number of conductors, BijRepresents the magnetic induction intensity, s, generated by the unit current of the ith conductor in the sensitivity direction of the jth TMR chipiThe slope of the piecewise linear function, U, representing the ith TMR chip output voltageiIs the output voltage of the ith TMR chip, ciIntercept of piecewise linear function of output voltage of ith TMR chip, IiIs the current of the ith conductor, i ═ 1,2, …, n; j is 1,2,3, …, n;
and obtaining the final current value of the tested conductor according to the output of the chip and substituting the output of the chip into the model, and eliminating the influence of interference conductors by a linear equation solving mode through the method so as to obtain the accurate current value of the tested conductor.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (3)
1. A multi-conductor current measuring system based on TMR tunnel magnetic resistance is characterized in that: the TMR chip array comprises a TMR chip array and a processing unit connected with the output end of the TMR chip array;
the TMR chip array comprises m TMR chips, wherein the m TMR chips are all positioned under the axial center line of a main conductor to be tested, the m TMR chips are sequentially arranged from top to bottom, adjacent chips are arranged at equal intervals, the distance between the TMR chip with the minimum distance from the main conductor to be tested and the main conductor to be tested is equal to the interval between the adjacent chips, and the processing unit obtains the current of the conductor to be tested from the main conductor according to a voltage signal output by the TMR chips;
the processing unit comprises a differential signal conversion circuit, a bias processing circuit and a microcontroller;
the input end of the differential signal conversion circuit is connected with the output end of the TMR chip and is used for converting the differential signal output by the TMR chip into a single-ended signal and outputting the single-ended signal;
the input end of the bias processing circuit is connected with the output end of the differential signal conversion circuit and used for converting the single-ended signal into a positive voltage signal and inputting the positive voltage signal into the microcontroller;
the microcontroller is used for receiving the positive voltage signal output by the bias processing circuit and outputting the current value of the detected conductor according to the positive voltage signal;
the microcontroller obtains the current of the tested conductor according to the following method:
performing piecewise linear approximation on an output voltage curve of the TMR chip to obtain a piecewise linear function U of the TMR output voltage curve U and the magnetic induction intensity, wherein s is the slope of the piecewise function, B is the magnetic induction intensity component in the sensitive direction of the chip, and c is the intercept of the piecewise function;
constructing a model of the measured current and magnetic induction intensity and TMR chip output voltage:
wherein n represents the number of conductors, BijRepresents the magnetic induction intensity, s, generated by the unit current of the ith conductor in the sensitivity direction of the jth TMR chipiThe slope of the piecewise linear function, U, representing the ith TMR chip output voltageiIs the output voltage of the ith TMR chip, ciIntercept of piecewise linear function of output voltage of ith TMR chip, IiIs the ith leadBulk current, i ═ 1,2, …, n; j is 1,2,3, …, n; discarding the output data of a plurality of chips when the number of conductors is less than the number of chips;
and obtaining the final current value of the tested conductor according to the chip output substitution model.
2. The TMR tunnel magnetoresistive-based multi-conductor current measurement system as claimed in claim 1, wherein: the processing circuit further comprises a display, and the display is in communication connection with the microcontroller.
3. The TMR tunnel magnetoresistive-based multi-conductor current measurement system as claimed in claim 1, wherein: the microcontroller is a single chip microcomputer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2019104595983 | 2019-05-29 | ||
| CN201910459598 | 2019-05-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111521857A CN111521857A (en) | 2020-08-11 |
| CN111521857B true CN111521857B (en) | 2021-05-25 |
Family
ID=71905240
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010366631.0A Expired - Fee Related CN111521857B (en) | 2019-05-29 | 2020-04-30 | Multi-conductor current measuring system based on TMR tunnel magnetic resistance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111521857B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112595873B (en) * | 2020-09-18 | 2022-05-17 | 国网江苏省电力有限公司徐州供电分公司 | Current sensor based on triaxial tunnel magnetoresistive array and measuring method thereof |
| CN113325228B (en) * | 2021-06-04 | 2022-09-16 | 江苏大学 | Single-side current detection device and method based on magnetoresistive effect sensor array |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102099695A (en) * | 2008-07-22 | 2011-06-15 | Abb研究有限公司 | Magnetoresistive sensor arrangement for current measurement |
| CN103809008A (en) * | 2012-11-13 | 2014-05-21 | 郑律 | TMR current sensor and current detection method |
| CN106018942A (en) * | 2016-06-28 | 2016-10-12 | 清华大学 | Current sensor array used for measuring three-phase current and measuring method thereof |
| CN109009065A (en) * | 2018-06-05 | 2018-12-18 | 上海理工大学 | Brain magnetic information detection system and method based on TMR weak magnetic sensor array |
| CN208888302U (en) * | 2018-09-28 | 2019-05-21 | 南方电网科学研究院有限责任公司 | The measuring device of line current in a kind of electric system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7164263B2 (en) * | 2004-01-16 | 2007-01-16 | Fieldmetrics, Inc. | Current sensor |
| JP2009059986A (en) * | 2007-09-03 | 2009-03-19 | Tdk Corp | Signal detection apparatus |
-
2020
- 2020-04-30 CN CN202010366631.0A patent/CN111521857B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102099695A (en) * | 2008-07-22 | 2011-06-15 | Abb研究有限公司 | Magnetoresistive sensor arrangement for current measurement |
| CN103809008A (en) * | 2012-11-13 | 2014-05-21 | 郑律 | TMR current sensor and current detection method |
| CN106018942A (en) * | 2016-06-28 | 2016-10-12 | 清华大学 | Current sensor array used for measuring three-phase current and measuring method thereof |
| CN109009065A (en) * | 2018-06-05 | 2018-12-18 | 上海理工大学 | Brain magnetic information detection system and method based on TMR weak magnetic sensor array |
| CN208888302U (en) * | 2018-09-28 | 2019-05-21 | 南方电网科学研究院有限责任公司 | The measuring device of line current in a kind of electric system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111521857A (en) | 2020-08-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101297200B1 (en) | Point detecting type current measuring device having function of compensating interference by adjacent bus bar | |
| US7511468B2 (en) | Harmonics measurement instrument with in-situ calibration | |
| CN107328980B (en) | Multi-core cable non-invasive current measuring method and measuring device | |
| CN111521857B (en) | Multi-conductor current measuring system based on TMR tunnel magnetic resistance | |
| CN110018434B (en) | Voltage measurement device correction method, device and system | |
| US8768635B2 (en) | Systems and methods for determining electrical faults | |
| CN111337733B (en) | TMR-based busbar current and magnetic field intensity measuring device | |
| CN109001997B (en) | Anti-interference environment information acquisition system | |
| CN103308817B (en) | Array base palte line detection apparatus and detection method | |
| RU2727565C1 (en) | Current measurement method and current measurement device | |
| EP4214521A1 (en) | Non-contact electrical parameter measurement device with radial dual mounted sensors | |
| CN105300269B (en) | A kind of wireless accurate strain gauge means and a kind of wireless accurate strain measurement method | |
| EP2833157B1 (en) | Identifying defective electrical cables | |
| CN102023270A (en) | Intelligent power network parameter sensor | |
| CN210037946U (en) | Current measuring device based on TMR tunnel magnetic resistance | |
| CN102478422A (en) | Zero drift simulation calibrating method and device thereof | |
| CN107132500A (en) | A kind of synchronous phasor measurement unit on-line calibration method and apparatus | |
| CN104678339B (en) | Calibration device, system and method for probe type microwave voltage measurement system | |
| CN214750535U (en) | Current segmentation sampling system | |
| US20050068020A1 (en) | Method and apparatus for determining a current in a conductor | |
| JP2014163914A (en) | Accident point orientation device | |
| CN219935963U (en) | Voltage and current measurement channel of digital bridge and digital bridge | |
| CN110470931B (en) | Method for measuring radiation sensitive parameters of operational amplifier | |
| CN113406483B (en) | Anti-interference detection system of metering chip and computer readable storage medium | |
| US20240044944A1 (en) | Current detection apparatus and current detection method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20210525 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |