CN105353192A - Current sensor - Google Patents
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- CN105353192A CN105353192A CN201510809406.9A CN201510809406A CN105353192A CN 105353192 A CN105353192 A CN 105353192A CN 201510809406 A CN201510809406 A CN 201510809406A CN 105353192 A CN105353192 A CN 105353192A
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Abstract
The invention discloses a current sensor. The current sensor comprises multiple sensing units in series connection, the multiple sensing units surround a to-be-detected lead for m loops, distances between adjacent sensing units on each loop are identical, the number of the sensing units on each loop is respectively identical, and the m is greater than or equal to 1. The invention further discloses a current sensor comprising multiple sensing units in parallel connection, the multiple sensing units surround the to-be-detected lead for m loops, distances between adjacent sensing units on each loop are identical, the number of the sensing units on each loop is respectively identical, and the m is greater than or equal to 1. The current sensor employs anisotropic magneto-resistor elements, giant magneto-resistor elements or magnetic tunnel junction elements as sensing elements and further has advantages of high precision, high sensitivity and low cost.
Description
Technical field
The present invention relates to current sensing techniques field, particularly a kind of current sensor.
Background technology
Current measuring device is generally that the magnetic field size produced by tested electric current realizes the measurement of electric current, the magnetic current sensor being sensitive element with Hall element and magnetoresistive element compares to optical fiber and coil type current sensor has higher precision and sensitivity, and can use under greasy dirt and extreme temperature environment.Hall current sensor is current the most widely used current sensor device, it utilizes Hall effect principle measure the field intensity of electrified wire and then obtain the size of electric current, Hall element measurement range is wide, but sensitivity and precision are very low, therefore be that the current sensor of sensitive element needs to arrange extra magnetism gathering rings structure with Hall element, volume is very large, and with high precision and highly sensitive magnetoresistive element (anisotropic magnetoresistance, giant magnetoresistance and magnetic tunnel junction element) for the current sensor of sensitive element more and more becomes main flow.
The patent of China publication number CN101788596A: the current sensor that it is sensitive element that TMR current sensor discloses with TMR element (i.e. magnetic tunnel junction element), it comprises the current sensor of chip integrated, PCB integrated form and separate type three kinds of structures.Although adopt the current sensor of magnetoresistive element due to its high sensitivity and high-precision feature in theory, do not need extra magnetism gathering rings, but in actual use, particularly for the measurement of big current, the current sensor of magnetic tunnel junction element is adopted generally to adopt such structure: from loop, to introduce electric current to be measured with a current lead, magnetism gathering rings is set around wire to be measured in order to converge magnetic field, be positioned at the sensor chip at magnetism gathering rings air gap place in order to measure magnetic field, and then obtain the size of electric current to be measured.As can be seen from above-mentioned, magnetism gathering rings is inevitable in actual applications, this results in series of problems: (1) magnetism gathering rings has magnetic hysteresis, can reduce the precision of sensor; (2) price of magnetism gathering rings is higher, and volume is comparatively large, can improve the cost of sensor, increases the volume of sensor; (3) temperature characterisitic of magnetism gathering rings is poor, and easily saturated, greatly reduces the precision of sensor.
The patent of China publication number CN203786190U: a kind of tunnel magnetoresistive current sensor discloses a kind of mode adopting 8 the more than tunnel magnetoresistive chip measurement electric currents of equidistant arrangement ringwise, but this patent exists the situation of insufficient disclosure, the technology that those of ordinary skill in the art is difficult to be disclosed by this patent manufactures such sensor.
Summary of the invention
Technical matters to be solved by this invention overcomes the deficiencies in the prior art and provides a kind of current sensor, the present invention adopts anisotropic magnetoresistance element, giant magnetoresistance element or magnetic tunnel junction element to be the current sensor of sensitive element, and this sensor accuracy is high, highly sensitive and cost is low.
The present invention is for solving the problems of the technologies described above by the following technical solutions:
According to a kind of current sensor that the present invention proposes, comprise the sensing unit of multiple series connection, described sensing unit encloses around wire m to be measured, and the distance between the upper adjacent sensing unit of each circle is equal, and the number of the sensing unit often on circle is all identical; Wherein, m >=1.
As the further prioritization scheme of a kind of current sensor of the present invention, described sensing unit comprises single resistance, half-bridge or the full bridge structure that at least one magnetic sensor elements is formed.
As the further prioritization scheme of a kind of current sensor of the present invention, described magnetic sensor elements is anisotropic magnetoresistance element, giant magnetoresistance element or magnetic tunnel junction element.
As the further prioritization scheme of a kind of current sensor of the present invention, during described m >=2, the sensing unit on each circle is all positioned on corresponding line, and described corresponding line is the sensing unit of innermost circle and the line at wire center.
As the further prioritization scheme of a kind of current sensor of the present invention, also comprise temperature compensation unit, described temperature compensation unit is connected with multiple sensing unit.
As the further prioritization scheme of a kind of current sensor of the present invention, also comprise the amplifier unit be connected with multiple sensing unit.
A kind of current sensor, comprise the sensing unit of multiple parallel connection, described sensing unit encloses around wire m to be measured, and the distance between the upper adjacent sensing unit of each circle is equal, and the number of the sensing unit often on circle is all identical; Wherein, m >=1.
As the further prioritization scheme of a kind of current sensor of the present invention, during described m >=2, the sensing unit on each circle is all positioned on corresponding line, and described corresponding line is the sensing unit of innermost circle and the line at wire center.
As the further prioritization scheme of a kind of current sensor of the present invention, also comprise temperature compensation unit, described temperature compensation unit is connected with multiple sensing unit.
As the further prioritization scheme of a kind of current sensor of the present invention, also comprise the amplifier unit be connected with multiple sensing unit.
The present invention adopts above technical scheme compared with prior art, have following technique effect: the present invention adopts anisotropic magnetoresistance element, giant magnetoresistance element or magnetic tunnel junction element to be the current sensor of sensitive element, this sensor has high precision, high sensitivity, feature that cost is low.
Accompanying drawing explanation
Fig. 1 is structure and the electrical connection schematic diagram of the embodiment one of the current sensor that the present invention proposes.
Fig. 2 is structure and the electrical connection schematic diagram of the embodiment two of the current sensor that the present invention proposes.
Fig. 3 is structure and the electrical connection schematic diagram of the embodiment three of the current sensor that the present invention proposes.
Fig. 4 is the electrical connection schematic diagram of the embodiment two of the current sensor that the present invention proposes.
Fig. 5 adopts single resistance or half-bridge structure to be the output curve diagram of the current sensor of sensing unit.
Fig. 6 adopts full bridge structure to be the output curve diagram of the current sensor of sensing unit.
Reference numeral in figure is interpreted as: 11a, 11b, 11c ... 11n is sensing unit, 21-wire to be measured, 13a, 13b, 13c ... 13n is sensing unit.
Embodiment
Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:
Technical scheme in the application is understood better in order to make those skilled in the art person, below in conjunction with the accompanying drawing in the embodiment of the present application, technical scheme in the embodiment of the present application is clearly and completely described, obviously, described embodiment is only some embodiments of the present application, instead of whole embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all should belong to the scope of the application's protection.
Fig. 1 is structure and the electrical connection schematic diagram of a kind of embodiment of the current sensor that the present invention proposes.As shown in the figure, multiple sensing unit 11a, 11b, 11c ... 11n is to be equidistantly looped around around wire 21 to be measured, and each sensing unit can measure the magnetic field size of its position, and described n sensing unit series connection, its input port is
v cCand GND, described current sensor is connected into system by input port and passes into working current, simultaneously
v cCport and GND port are also its output ports, and its output valve is total output valve of multiple sensing units of series connection.
Fig. 2 is structure and the electrical connection schematic diagram of the second embodiment of the current sensor that the present invention proposes.As shown in the figure, multiple sensing unit 11a, 11b, 11c ... 11n, 13a, 13b, 13c ... 13n is to be equidistantly looped around two circles around wire 21 to be measured, each sensing unit can measure the magnetic field size of its position, wherein, sensing unit 11a, 11b, 11c ... 11n is looped around outer ring, sensing unit 13a, 13b, 13c ... 13n is looped around inner ring, the sensing unit number of outer ring is identical with the sensing unit number of inner ring, multiple sensing unit 11a, 11b, 11c ... 11n, 13a, 13b, 13c ... 13n connects, and its input port is
v cCand GND, described current sensor is connected into system by input port and passes into working current, and its output port is
v oUTwith
v cC, or
v oUTand GND, the outer ring sensing unit of series connection and inner ring sensing unit form a half-bridge structure, and its output valve is the output valve of an equivalent brachium pontis of this half-bridge, and its electric connection mode is as described in Figure 4.
Fig. 3 is structure and the electrical connection schematic diagram of the third embodiment of the current sensor that the present invention proposes.As shown in the figure, multiple sensing unit 11a, 11b, 11c ... 11n is to be equidistantly looped around around wire 21 to be measured, and each sensing unit can measure the magnetic field size of its position, and described n sensing unit is in parallel, and its input port is
v cCand GND, described current sensor is connected into system by input port and passes into working current, simultaneously
v cCport and GND port are also its output ports, and its output valve is total output valve of multiple sensing units in parallel.Sensing unit 11 is for half-bridge structure is so that describe its electric connection mode in fig. 3, and in practical application, it is not limited only to half-bridge structure, also can be single resistance or full bridge structure.
Three kinds of above-mentioned embodiments have employed multiple sensing unit and measure alternative magnetism gathering rings, thus overcome the series of problems of magnetism gathering rings: having magnetic hysteresis affects precision, and price is higher to raise the cost, and saturation field is little.Adopt multiple sensing unit measurements of series connection and semibridge system series connection to be actually to be equivalent to the signal of multiple sensing unit to amplify, the effect of magnetism gathering rings is instead of with total output of multiple sensing unit, due to Ampère circuital theorem, adopt multiple sensing unit to measure and can strengthen anti-external magnetic field interference performance, reduce internal current line position to the impact of measuring simultaneously; Adopt total output of multiple sensing unit parallel connection to be actually the average of multiple sensing unit measurement result, thus above-mentioned interference can be reduced, improve measuring accuracy.Above-mentioned multiple sensing unit is not limited only to be arranged in and makes a circle in wire week, also can be two circles and multi-turn, the current sensor adopting multiple sensing unit multi-turn to connect can be that total output of multi-turn sensing unit is for exporting, also can be individual pen be one group of output signal, need knownly often enclose the number of sensing unit and often enclose the distance of sensing unit apart from the wire center of circle to be measured; In parallel in like manner total output of multi-turn or individual pen can be adopted to be one group of outputs, need known often enclose sensing unit number and often circle sensing unit apart from the distance in the wire center of circle to be measured.The arrangement mode of the sensing unit that each sensing unit is corresponding with its adjacent turn preferably arranges along the diameter of conductive wire cross-section, also can misplace, by Biot-Savart law, for the long straight conductor that is infinitely energized,
b=
μ 0 i/ (2
π r 0), knownly often enclose the output of sensing unit or always export
v(by output voltage
vknown magnetic induction density
b), often enclose the number n of sensing unit and often enclose the distance of sensing unit apart from the wire center of circle to be measured
r, the electric current of electrified wire can be calculated
isize.Due in actual use, can due to install or the reason such as environmental vibration to make often to enclose each sensing unit apart from the distance in the wire center of circle to be measured be not etc., but have employed multiple sensing unit can make error-correction model, improves measuring accuracy.The fixed form of multiple sensing unit can be PCB, also can be flexible PCB, and the advantage adopting flexible PCB is collapsible, is attached to by sensor on wire to be measured during measurement, very convenient.
Because sensing unit has the characteristic of temperature drift, therefore measurement result can be affected, especially when temperature environment is severe.Therefore can arrange one to external world the insensitive sensing unit in magnetic field as temperature compensation unit, the sensing unit series connection dividing potential drop of this temperature compensation unit and above-mentioned multiple serial or parallel connection, when temperature rises or decline, the resistance of temperature compensation unit and multiple sensing unit increases simultaneously or reduces, thus realizes the object of temperature compensation.The specific works mode of temperature compensation unit can be the patent of CN102419393A with reference to Chinese publication number: a kind of current sensor.Meanwhile, in order to optimize output signal further, in the circuit loop of current sensor, amplifier unit can be set.
Above-mentioned sensing unit is all the single resistance, half-bridge or the full bridge structure that are made up of magnetic sensor elements, described magnetic sensor elements is Hall element, anisotropic magnetoresistance element, giant magnetoresistance element and/or magnetic tunnel junction element, preferred saturation field comparatively large and the giant magnetoresistance element that precision is very high and/or magnetic tunnel junction element.Giant magnetoresistance element and the magnetic tunnel junction element magnetoresistive element of change that is a kind of resistance with external magnetic field change, by existing technology magnetoresistive element
r-
h(resistance-external magnetic field) curve has low magnetic hysteresis, the characteristic of high saturation field and the wide range of linearity, relative to traditional magnetic sensor elements as telefault and Hall element have higher precision and better temperature characterisitic, have higher saturation field compared to anisotropic magnetoresistance element, its sensitive element as electricity leakage sensor is optimal.
Sensing unit can be single resistance, half-bridge or full bridge structure.The brachium pontis of described single resistance, half-bridge or full-bridge is connected by one or more identical magnetic sensor elements and/or is composed in parallel, each brachium pontis we can be equivalent to a magneto-resistor, the magnetic-field-sensitive direction of the magnetic sensor elements in each brachium pontis is identical.Aforesaid single electric resistance structure contains a magneto-resistor, and half-bridge structure is composed in series by the magneto-resistor that two physical propertys are identical, and full bridge structure is connected and composed by the magneto-resistor that four physical propertys are identical, all will pass into working current during use.Wherein, single resistance or half-bridge structure are optimum selection, single resistance or half-bridge curve of output as shown in Figure 5, wherein ,+
v peakwith-
v peakfor maximum output valve,
h sfor saturation field, its perform region is the range of linearity of curve of output.Full-bridge curve of output as shown in Figure 6.
The structural drawing of giant magnetoresistance element and magnetic tunnel element and principle of work, and the specific works mode of magnetic sensor chips can be the Chinese patent of CN103645369A with reference to publication number: a kind of current sensor device.
Obviously, the above embodiment of the present invention is only for example of the present invention is clearly described, and is not the restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without the need to also giving all embodiments.And these belong to connotation of the present invention the apparent change of extending out or variation still belong to protection scope of the present invention.
Claims (10)
1. a current sensor, is characterized in that, comprises the sensing unit of multiple series connection, and described sensing unit encloses around wire m to be measured, and the distance between the upper adjacent sensing unit of each circle is equal, and the number of the sensing unit often on circle is all identical; Wherein, m >=1.
2. a kind of current sensor according to claim 1, is characterized in that, described sensing unit comprises single resistance, half-bridge or the full bridge structure that at least one magnetic sensor elements is formed.
3. a kind of current sensor according to claim 2, is characterized in that, described magnetic sensor elements is anisotropic magnetoresistance element, giant magnetoresistance element or magnetic tunnel junction element.
4. a kind of current sensor according to claim 1, is characterized in that, during described m >=2, the sensing unit on each circle is all positioned on corresponding line, and described corresponding line is the sensing unit of innermost circle and the line at wire center.
5. a kind of current sensor according to claim 1, is characterized in that, also comprise temperature compensation unit, and described temperature compensation unit is connected with multiple sensing unit.
6. a kind of current sensor according to claim 1, is characterized in that, also comprises the amplifier unit be connected with multiple sensing unit.
7. a current sensor, is characterized in that, comprises the sensing unit of multiple parallel connection, and described sensing unit encloses around wire m to be measured, and the distance between the upper adjacent sensing unit of each circle is equal, and the number of the sensing unit often on circle is all identical; Wherein, m >=1.
8. a kind of current sensor according to claim 7, is characterized in that, during described m >=2, the sensing unit on each circle is all positioned on corresponding line, and described corresponding line is the sensing unit of innermost circle and the line at wire center.
9. a kind of current sensor according to claim 7, is characterized in that, also comprise temperature compensation unit, and described temperature compensation unit is connected with multiple sensing unit.
10. a kind of current sensor according to claim 7, is characterized in that, also comprises the amplifier unit be connected with multiple sensing unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510809406.9A CN105353192A (en) | 2015-11-19 | 2015-11-19 | Current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510809406.9A CN105353192A (en) | 2015-11-19 | 2015-11-19 | Current sensor |
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| Publication Number | Publication Date |
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| CN105353192A true CN105353192A (en) | 2016-02-24 |
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| CN201510809406.9A Pending CN105353192A (en) | 2015-11-19 | 2015-11-19 | Current sensor |
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Cited By (3)
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| CN106291061A (en) * | 2016-08-31 | 2017-01-04 | 无锡乐尔科技有限公司 | A kind of current sensor, processing module and current measuring method |
| WO2019205775A1 (en) * | 2018-04-27 | 2019-10-31 | 宁波希磁电子科技有限公司 | Current sensor |
| CN113917216A (en) * | 2021-10-08 | 2022-01-11 | 江苏多维科技有限公司 | A current measuring device |
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Application publication date: 20160224 |