CN1967268A - Indirect induction type current-sensing device - Google Patents
Indirect induction type current-sensing device Download PDFInfo
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- CN1967268A CN1967268A CN 200510019815 CN200510019815A CN1967268A CN 1967268 A CN1967268 A CN 1967268A CN 200510019815 CN200510019815 CN 200510019815 CN 200510019815 A CN200510019815 A CN 200510019815A CN 1967268 A CN1967268 A CN 1967268A
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- coil
- operational amplifier
- current
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Abstract
An indirect sensing current sensor is equipped with the hollow measurement coil 1, the linear operational amplifier 2; the hollow measurement coil 1 insulates with the measured current conductor 3 and closely attached, and one end of the coil 1 connects with an input end of the linear operational amplifier 2 through the resistor R1, another end of the coil 1 connecting to the ground, another end of the linear operational amplifier 2 connecting to the ground through the grounding resistor R3; the coil 1 can also two-line parallel wind the DC current to measure the exciting coils 4, 5, and the two ends of the exciting coils 4, 5 connects with AC power, the two tail end interconnected. The invention is characterized by: 1. indirectly measuring the measured current, and no contact on the measured current circuit, completely insulation isolated; 2. volume size small, light weight, saving a lot of copper material, and the power consumption is very low power; 3. the first measuring signal has no relation with temperature, and then the hollow measurement coil has good linear characteristic, and its EMF also has good linearity rate.
Description
Technical field
The present invention relates to the ac and dc current sensor technical field, particularly a kind of indirect induction type current-sensing.
Background technology
At electric power, metallurgical, chemical industry, nuclear physics, the multiple industry of power electronics, science and technology field all relates to the ac and dc current problems of measurement, tested electric current often is in high voltage, in the current state, each industry, the robotization of the consumer of science and technology field, intelligent, digitizing, networking, the integrated inevitable development trend that become, the development trend of technical progress is more and more higher to the requirement of alterating and direct current flow parameter measurement, not only require measuring accuracy to improve, but also require surveying instrument to have high reliability, stability, low-power consumption, working service is convenient.
In the prior art, electric current detecting method has following several: electromagnetic current transducer, photo-electric current sensor, hall effect current sensor, resistance type current sensor, direct measuring type current sensor.
Various current sensors will be finished its specific function in transient process He under the short-circuit conditions, when transient process and short circuit, the primary power source aperiodic component is big, and decay is slow, easily causes misoperation.Electromagnetic current transducer is at present most widely used general, though its simple possible, but along with improving constantly of electric power transfer capacity, (electric pressure has reached 500KV or higher), its shortcoming is also more and more outstanding, as magnetic saturation, ferroresonance, dynamic range is little, frequency band is narrow, power consumption is big, simultaneously, electromagnetic current transducer also exists starting material such as need exhausting a large amount of copper and silicon steel, volume size big, heavy, gives the shortcoming that accumulating brings difficulty is installed.The temperature coefficient of hall effect current sensor is big, and poor stability causes measuring accuracy not high, brings restriction to application.Resistance type current sensor, electrical characteristics are good, and are simple in structure, but its temperature characterisitic is bad, and overload capacity is limited.
The photo-electric current sensor has that anti-electromagnetic interference (EMI), no saturated, measurement range are big, a little advantage such as in light weight of bandwidth, volume, but temperature influence is big, and complex structure is made difficulty.The direct measuring type current sensor has the every advantage of the sensor, and weak point but has 3 points: the one, and great current sensor will consume a large amount of copper materials, and the 2nd, increase line contacts, increase contact resistance, make troubles to installation, the 3rd, be related with tested current circuit, have and use dangerous suspicion.
Summary of the invention
The purpose of this invention is to provide a kind of measuring accuracy height, temperature influence not, volume is little, a naked difficult problem, few, safe and reliable, the easy for installation simple indirect induction type current-sensing of consumptive material.
Described indirect induction type current-sensing is characterized in that: described sensor is provided with hollow measurement coil 1, linear operational amplifier 2; Hollow measurement coil 1 is with tested Ampereconductors 3 insulation and near contacting, an end of hollow measurement coil 1 is through resistance R
1Be connected with an input end of linear operational amplifier 2, the other end ground connection of hollow measurement coil 1, another input end of linear operational amplifier 2 is through stake resistance R
3Be connected with ground; But on the air core coil 1 also two-wire and around dc current measurement with magnetizing coil 4,5, two head ends of magnetizing coil 4,5 are connected with AC power, its two tail end interconnects.Linear operational amplifier 2 also is provided with feedback resistance R
2, feedback resistance R
2An end be connected with an input end of linear operational amplifier 2, the other end is connected with the output terminal of linear operational amplifier 2.Be provided with insulation course between magnetizing coil 4,5 and the hollow measurement coil 1.The Insulating frame of hollow measurement coil 1 is circle or rectangle or other shapes.Be provided with insulation course between magnetizing coil 4,5 and the hollow measurement coil 1.
Its measuring principle is: according to electromagnetic induction principle, electric current in the measured conductor can produce magnetic flux at conductor crosscut surface level, this magnetic flux is by immediate air core coil, because of this magnetic flux is an alternation, so in air core coil, just produce induced potential, the size of the induced potential linear relationship that is directly proportional with size of current in the measured conductor is delivered to linear amplifier to this induced potential and is amplified, and just can obtain desired measuring-signal from the output terminal of linear amplifier.According to the principles of electric and electronic engineering as can be known, the induced potential that air core coil produces is temperature independent, thereby the linearity that has guaranteed the one-shot measurement signal is a temperature independent linear signal.
The measurement of DC current and the measurement of alternating current are slightly variant, add on hollow measurement coil 1 exactly around the coil that two groups of equal turn numbers, impedance equate, resistance equates, as magnetizing coil.Because the magnetic flux that DC current produces is unidirectional, is not alternation, measuring does not have induced potential to produce in the coil, for this reason, must provide excitatory with magnetizing coil.Magnetizing coil will be connected into differential type, adds AC power at the magnetizing coil two ends then.When measured DC was zero, because of magnetizing coil is connected into differential type, the magnetic flux of two groups of coil generations was cancelled out each other, and measures coil and is output as zero.When measured DC is non-vanishing, under the effect of magnetizing coil 4,5, produce the magnetic flux of alternation, measuring coil just has induced potential to produce, the size of the induced potential linear relationship that is directly proportional with the size of measured DC, and temperature independent, induced potential is delivered to linear amplifier amplify, just can obtain desired measuring-signal from amplifier out.
Characteristics of the present invention are: 1, measure tested electric current indirectly, the circuit of current sensor and tested electric current is without any getting in touch on the circuit, and insulation is isolated fully, makes the safety of instrument and meter, equipment facility and personal safety that guarantee arranged.
2, volume size little, in light weight, be convenient to production, installation and accumulating, especially great current sensor, can save a large amount of copper materials, institute's consumption material be traditional mutual inductor 5% in, self power consumption is little power consumption.
3, because of adopting air core coil, according to the electrotechnics principle as can be known, its induced potential size is temperature influence not, so the one-shot measurement signal is temperature independent; Next is that hollow measurement coil has the favorable linearity characteristic, thereby its induced potential also has good linearty.
The invention has the beneficial effects as follows: simple in structure, low cost of manufacture, little, easy to install, the on-line continuous measuring accuracy height of volume, can save a large amount of power consumptions, save a large amount of copper materials and permeability magnetic material, be fit to the usefulness of various industry, science and technology field measurement ac and dc current.
Description of drawings
Fig. 1 is the ac current measurement schematic diagram,
Fig. 2 is the dc current measurement schematic diagram,
Fig. 3 is tested electric current and operational amplifier output voltage graph of a relation.
Among the figure: the hollow measurement coil of 1-; The 2-linear operational amplifier; The tested Ampereconductors of 3-; 4,5-magnetizing coil; The R-conductor resistance; R
1-input resistance; R
2-feedback resistance; R
3-stake resistance; The induced potential of the hollow measurement coil of Ei-; The Vo-output signal; ※-winding head.
Embodiment
The invention will be further described to engage accompanying drawing below: among Fig. 1,2, hollow measurement coil 1 is with tested Ampereconductors 3 insulation and near contacting, an end of hollow measurement coil 1 is through resistance R
1Be connected with an input end of linear operational amplifier 2, the other end ground connection of hollow measurement coil 1, another input end of linear operational amplifier 2 is through stake resistance R
3Be connected with ground; But on the air core coil 1 also two-wire and around dc current measurement with magnetizing coil 4,5, two head ends of magnetizing coil 4,5 are connected with AC power, its two tail end interconnects.Feedback resistance R
2An end be connected with an input end of linear operational amplifier 2, the other end is connected with the output terminal of linear operational amplifier 2.Be provided with insulation course between magnetizing coil 4,5 and the hollow measurement coil 1.The Insulating frame of hollow measurement coil 1 is circle or rectangle or other shapes.
Be provided with insulation course between magnetizing coil 4,5 and the hollow measurement coil 1.
The Insulating frame of hollow measurement coil 1 is circle or rectangle or other shapes.
On rectangle more than 0.5 square centimeter or round hollow Insulating frame, with the high strength insulating varniss envelope curve around multiturn (circle), as measuring coil, use same enameled wire two-wire again and around multiturn (circle), as magnetizing coil 4,5, these two kinds of coils around the time must note the differentiation of each coil head and tail, so that correctly and conveniently connect, if AC current sensor, magnetizing coil needn't around, only just passable around measuring coil, if be used to measure the sensor of DC current, magnetizing coil must around.
After coil winds, press the schematic diagram wiring.Measure the size of output signal, can be controlled by linear operational amplifier 2, output signal Vo can be got by following formula:
The induced potential Ei that measures coil can be sought knowledge by following formula
No-load voltage ratio by transformer concerns as can be known
U
1W
2＝EiW
1
U in the formula
1Be the pressure drop of measured current I on the effective section of conductor resistance R, W
1Be conductor, actual is 1, W
2For measuring the number of turn of coil.U
1Can be formulated as the substitution following formula can get
U
1Effective section of=IR
By formula 1. as seen, output signal V
0Size can determine with amplifying circuit, simultaneously as can be known, be linear relationship fully between output signal and the input signal.
In environment temperature-40 ℃～120 ℃ scope, the current measurement precision can reach 1 ‰ or higher, and measurement range is 1 ‰～3000% of a specified range, simple in structure, cost performance is high, safe and reliable.
Fig. 3 is the performance plot of measurement parameter and output voltage relation, as can be seen from Fig. 3 the linear relationship between input signal and output signal.
Embodiment: the alternating current test, the parameter testing condition:
Measure coil 2000 circles, magnetizing coil 2 * 1000 circles, air core coil is of a size of 0.8 * 1.2cm, and used instrument is
Digital multimeter and
Numeral pincers type reometer, record data are as follows:
Measured current I (A) amplifier output voltage V
0(V)
5 0.32
10 0.63
15 0.94
20 1.25
25 1.57
30 1.88
35 2.18
40 2.50
45 2.81
50 3.11
55 3.42
60 3.74
Claims (5)
1, a kind of indirect induction type current-sensing is characterized in that: described sensor is provided with hollow measurement coil (1), linear operational amplifier (2); Hollow measurement coil (1) is with tested Ampereconductors (3) insulation and near contacting, an end of hollow measurement coil (1) is through resistance (R
1) be connected with an input end of linear operational amplifier (2), the other end ground connection of hollow measurement coil (1), another input end of linear operational amplifier (2) is through stake resistance (R
3) be connected with ground; Hollow measurement coil (1) but on also two-wire and around dc current measurement with magnetizing coil (4,5), two head ends of magnetizing coil (4,5) are connected with AC power, its two tail end interconnects.
2, indirect induction type current-sensing according to claim 1 is characterized in that: described linear operational amplifier (2) also is provided with feedback resistance (R
2), feedback resistance (R
2) an end be connected with an input end of linear operational amplifier (2), the other end is connected with the output terminal of linear operational amplifier (2).
3, indirect induction type current-sensing according to claim 1 is characterized in that: be provided with insulation course between magnetizing coil (4,5) and the hollow measurement coil (1).
4, indirect induction type current-sensing according to claim 1 is characterized in that: hollow measurement coil (1) go up two-wire and around, equal turn numbers, the impedance that is used for two groups of magnetizing coils (4,5) of dc current measurement equates, resistance equates.
5, a kind of indirect induction type current-sensing is characterized in that: being added with the described sensor of magnetizing coil (4,5) on hollow measurement coil (1), is the measurement that is used for DC current, provides excitatory by last magnetizing coil, and magnetizing coil is connected into differential type.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510019815 CN1967268A (en) | 2005-11-16 | 2005-11-16 | Indirect induction type current-sensing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510019815 CN1967268A (en) | 2005-11-16 | 2005-11-16 | Indirect induction type current-sensing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1967268A true CN1967268A (en) | 2007-05-23 |
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ID=38076135
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200510019815 Pending CN1967268A (en) | 2005-11-16 | 2005-11-16 | Indirect induction type current-sensing device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103197274A (en) * | 2013-03-13 | 2013-07-10 | 江苏省电力公司电力科学研究院 | Calibration system and calibration method of alternating large current of current transformer |
| CN106932630A (en) * | 2017-04-21 | 2017-07-07 | 艾迪迪电气（苏州）有限公司 | Current transformer inducing method and side induction type current transformer |
-
2005
- 2005-11-16 CN CN 200510019815 patent/CN1967268A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103197274A (en) * | 2013-03-13 | 2013-07-10 | 江苏省电力公司电力科学研究院 | Calibration system and calibration method of alternating large current of current transformer |
| CN103197274B (en) * | 2013-03-13 | 2014-07-16 | 江苏省电力公司电力科学研究院 | Calibration system and calibration method of alternating large current of current transformer |
| CN106932630A (en) * | 2017-04-21 | 2017-07-07 | 艾迪迪电气（苏州）有限公司 | Current transformer inducing method and side induction type current transformer |
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