CN104576005B - AC current transformer - Google Patents
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- CN104576005B CN104576005B CN201410842078.8A CN201410842078A CN104576005B CN 104576005 B CN104576005 B CN 104576005B CN 201410842078 A CN201410842078 A CN 201410842078A CN 104576005 B CN104576005 B CN 104576005B
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- 238000004804 winding Methods 0.000 claims abstract description 70
- 230000005284 excitation Effects 0.000 claims abstract description 39
- 230000006698 induction Effects 0.000 claims abstract description 24
- 230000003321 amplification Effects 0.000 claims abstract description 16
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 16
- 230000035699 permeability Effects 0.000 description 14
- 230000009467 reduction Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 5
- 230000004907 flux Effects 0.000 description 4
- 238000005070 sampling Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
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- 230000009466 transformation Effects 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
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Abstract
The present invention relates to a kind of AC current transformer, including magnetic core, armature winding, the first secondary windings, second subprime winding, multi-gain amplification unit, load elements and auxiliary continuous current excitation circuit；Armature winding, the first secondary windings and second subprime winding are respectively arranged on magnetic core；Armature winding is used to be connected with circuit-under-test；With second subprime windings in series after first level windings in series multi-gain amplification unit；Second subprime winding is also connected with load elements；Auxiliary continuous current excitation circuit is used to provide continuous current excitation electric current；Continuous current excitation electric current is used to produce magnetic field so that the work magnetic induction intensity of magnetic core is between 4th/to five/5th of the saturation induction density of magnetic core.Above-mentioned AC current transformer causes that the magnetic conductivity of magnetic core is raised, and reduces the transformed error of AC current transformer, improves the precision of AC current transformer.
Description
Technical field
The present invention relates to transformer technical field, more particularly to a kind of AC current transformer.
Background technology
AC current transformer is one of critical component in electrical measuring instrument, and its precision directly affects the overall skill of instrument
Art index, therefore it is required that AC current transformer has the features such as stability is high, error is small.Traditional electronic compensation type Zero flux
Current transformer, its theory diagram is as shown in Figure 1.Electronic compensation type zero-flux current transformer includes Multiple coil transformer 1, height
Gain electronic circuit amplifying unit 2 and load resistance 3.Multiple coil transformer 1 includes armature winding N1, the first secondary windings N3
And second subprime winding N2.Wherein, LSIt is the equivalent magnetizing inductance of armature winding N1.High-gain electronic circuit amplifying unit 2
Multiplication factor be A, load resistance 3 be used for secondary current is sampled, its resistance value be RL.I is tested primary current, IS
It is exciting current, I0It is sample rate current.
Fig. 2 is magnetic induction density B, the transformer core magnetic permeability μ of the electronic compensation type zero-flux current transformer in Fig. 1
With the graph of relation of magnetic field intensity H.Traditional electronic compensation type zero-flux current transformer is operated in 1 region (zero magnetic of Fig. 2
It is logical), its transformed error ε and load resistance RL, multiplication factor A and primary magnetizing inductance LSIt is related etc. factor, formula (1), (2) can be used
Represent：
In formula (2), AeIt is transformer core sectional area, LeIt is the transformer core length of magnetic path.
From formula (1), the transformed error ε and load resistance R of electronic compensation type zero-flux current transformerLCheng Zheng
Than with multiplication factor A, magnetizing inductance LSIt is inversely proportional.To improve the sampling precision of current transformer, conditional electronic compensation way is equal
It is by reducing load resistance RLAnd improve multiplication factor A and allow the transformer to be worked close to Zero flux, i.e. transformer workspace
Domain is from 1 in Fig. 2 to 2 transformations.When transformer core works close to Zero flux, according to magnetic permeability μ in Fig. 2 and magnetic field intensity H
Graph of relation understand, magnetic permeability μ is also decreased.Understood according to formula (2), magnetic permeability μ reduction, magnetizing inductance LSSubtract
It is small, transformed error increase, precision reduction, this and reduce load resistance RL, improve gain multiplication factor A take measures to form contradiction
Relation.Also, for the consideration of the stability to electronic circuit and sampled signal signal to noise ratio, the raising of gain multiplication factor A
And load resistance RLReduction it is very limited, therefore traditional zero-flux current transformer based on electronic compensation type still suffer from it is larger
Transformed error, precision is relatively low so that the current transformer adopted in this way is limited in the application of higher precision field of electric measurement.
The content of the invention
Based on this, it is necessary to regarding to the issue above, there is provided a kind of high-precision AC current transformer.
A kind of AC current transformer, including magnetic core, armature winding, the first secondary windings, second subprime winding, gain are put
Big unit, load elements and auxiliary continuous current excitation circuit；The armature winding, first secondary windings and described second
Secondary windings is respectively arranged on the magnetic core；The armature winding is used to be connected with circuit-under-test；First secondary windings
Connect after the multi-gain amplification unit with the second subprime windings in series；The second subprime winding also with the load elements
Series connection；The auxiliary continuous current excitation circuit is used to provide continuous current excitation electric current；The continuous current excitation electric current makes for producing magnetic field
The magnetic core work magnetic induction intensity between 4th/to five/5th of the saturation induction density of the magnetic core.
Wherein in one embodiment, the auxiliary continuous current excitation circuit includes DC source of energization and assists winding；Institute
State DC source of energization and form loop with the assists winding；The assists winding is arranged on the magnetic core.
Wherein in one embodiment, the DC source of energization is direct current constant current drive source.
Wherein in one embodiment, the auxiliary continuous current excitation circuit includes DC source of energization；The DC source of energization
With first level winding parallel.
Wherein in one embodiment, the DC source of energization is direct current constant current drive source.
Wherein in one embodiment, the load elements are load resistance.
Wherein in one embodiment, the input of the multi-gain amplification unit is connected with first secondary windings, institute
The output end for stating multi-gain amplification unit is connected with the second subprime winding.
Wherein in one embodiment, the continuous current excitation electric current is used to produce magnetic field so that the magnetic core is operated in magnetic conductance
At the maximum position of rate.
Above-mentioned AC current transformer is provided with auxiliary continuous current excitation circuit, and auxiliary continuous current excitation circuit can provide direct current and swash
Encourage electric current.The continuous current excitation electric current can encourage generation magnetic field so that the work magnetic induction intensity of magnetic core is in magnetic core saturation magnetic strength
Answer between 4th/to five/5th of intensity so that the magnetic conductivity of magnetic core is raised, reduce turning for AC current transformer
Error is changed, the precision of AC current transformer is improve.
Brief description of the drawings
Fig. 1 is the theory diagram of traditional electronic compensation type zero-flux current transformer；
Fig. 2 is magnetic induction density B, the magnetic core magnetic of the electronic compensation type zero-flux current transformer in embodiment illustrated in fig. 1
The graph of relation of conductance μ and magnetic field intensity H；
Fig. 3 is the theory diagram of the AC current transformer in an embodiment；
Fig. 4 is the theory diagram of the AC current transformer in another embodiment；
Fig. 5 is the magnetic induction density B of the AC current transformer in an embodiment, magnetic permeability μ and magnetic field intensity H
Graph of relation.
Specific embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
A kind of AC current transformer, including magnetic core, armature winding, the first secondary windings, second subprime winding, gain are put
Big unit, load elements and auxiliary continuous current excitation circuit.Armature winding, the first secondary windings and second subprime winding difference
It is arranged on magnetic core.Armature winding is used to be connected with circuit-under-test；With second subprime after first level windings in series amplifying unit
Windings in series.Second subprime winding is also connected with load elements.Auxiliary continuous current excitation circuit is used to provide continuous current excitation electric current.Directly
Stream exciting current be used for produce magnetic field so that magnetic core work magnetic induction intensity magnetic core saturation induction density five/
Between 4/1sts to five.Preferably, the magnetic field that continuous current excitation electric current is produced enables to the magnetic core of the course of work to obtain maximum
Magnetic conductivity.
Above-mentioned AC current transformer is provided with auxiliary on the basis of original electronic compensation type zero-flux current transformer
Helping continuous current excitation circuit, auxiliary continuous current excitation circuit can provide continuous current excitation electric current.The continuous current excitation electric current can encourage generation magnetic
So that the work magnetic induction intensity of magnetic core is between 4th/to five/5th of magnetic core saturation induction density, from
And cause that the magnetic conductivity of magnetic core is raised, and reduces the transformed error of AC current transformer, improve AC current transformer
Precision.
Fig. 3 is the AC current transformer in an embodiment, and it includes magnetic core 210, armature winding N1, the first secondary windings
N3, second subprime winding N2, multi-gain amplification unit 220, load elements 230 and auxiliary continuous current excitation circuit 240.
In the present embodiment, armature winding N1, the first secondary windings N3, second subprime winding N2 may be contained within magnetic core 210
On.First secondary windings N3 is connected after being sequentially connected in series multi-gain amplification unit 220, second subprime winding N2 with load elements 230.Increase
The input of beneficial amplifying unit 220 is connected with the first secondary windings N3, the output end of multi-gain amplification unit 220 then with second subprime
Winding N2 is connected.In the present embodiment, load elements 230 are load resistance, and its resistance is RL.Multi-gain amplification unit 220 is used
High-gain electronic circuit amplifying unit, its multiplication factor is A.The multiplication factor of multi-gain amplification unit 220 can be according to specific
Operating circuit and required precision are set.
Auxiliary continuous current excitation circuit 240 includes DC source of energization 242 and assists winding N4.Wherein, DC source of energization 242
It is direct current constant current drive source, for providing constant continuous current excitation electric current Idc.Assists winding N4 is arranged on magnetic core 210.Direct current
Exciting current IdcGeneration magnetic field can be encouraged so that the work magnetic induction density B of magnetic core is in magnetic core saturation induction density Bs
The 1/5 of (saturation induction density also known as saturation flux density, refer to magnetic induction intensity when magnet is magnetized to saturation state)
Between~4/5, now magnetic core is operated in 3 regions.Preferably, continuous current excitation electric current IdcGeneration magnetic field Hdc can be encouraged so that magnetic
Core is operated in the maximum position μ of magnetic conductivitymPlace, as shown in Figure 5.Magnetic induction density B is in magnetic core saturation induction density Bs1/5
When between~4/5, the magnetic permeability μ of corresponding magnetic core is higher.And the relation between magnetic permeability μ and transformed error ε can be by formula
(1) (2) are indicated：
Therefore, when magnetic permeability μ is improved, corresponding primary magnetizing inductance LSImprove, and primary magnetizing inductance LSWith transformed error
ε is in inverse ratio, so that transformed error ε reductions, improve the precision of AC current transformer.
Now, then by reducing the resistance R of load resistanceL, the multiplication factor A that improves multi-gain amplification unit 220 increases
During sampling precision, the working region of magnetic core turns to 4 regions by 3 original regions, and magnetic permeability μ is also improved therewith, primary excitation electricity
Sense LSImprove, so that transformed error ε reductions, further increase the precision of AC current transformer, so as to solve biography
The resistance R of the reduction load resistance that system electronic compensation type zero-flux current transformer is presentL, improve multiplication factor A when can cause
(1 region and 2 regions are the workspace of traditional electronic compensation type zero-flux current transformer to the problem of magnetic permeability μ reduction in Fig. 5
Domain).
Fig. 4 is the theory diagram of the AC current transformer in another embodiment, including magnetic core 310, armature winding N1,
One secondary windings N3, second subprime winding N2, multi-gain amplification unit 320, load elements 330 and auxiliary continuous current excitation circuit
340。
In the present embodiment, auxiliary continuous current excitation circuit 340 includes DC source of energization.DC source of energization and first level around
Group N3 is in parallel.DC source of energization is direct current constant current drive source, for providing constant continuous current excitation electric current Idc.Continuous current excitation electric current
IdcGeneration magnetic field can be encouraged so that the work magnetic induction density B of magnetic core is in magnetic core saturation induction density Bs1/5~4/5
Between, now magnetic core is operated in 3 regions.Preferably, continuous current excitation electric current IdcGeneration magnetic field Hdc can be encouraged so that magnetic core works
In the position μ that magnetic conductivity is maximummPlace.
Magnetic induction density B is in magnetic core saturation induction density Bs1/5~4/5 between when, the magnetic permeability μ of corresponding magnetic core
It is higher.When magnetic permeability μ is improved, corresponding primary magnetizing inductance LSImprove, and primary magnetizing inductance LSIt is in inverse ratio with transformed error ε,
So that transformed error ε reductions, improve the precision of AC current transformer.Now, then by reducing the resistance of load resistance
Value RL, the multiplication factor A that improves multi-gain amplification unit 220 increase during sampling precision, the working region of magnetic core is by 3rd original area
Domain turns to 4 regions, and magnetic permeability μ is also improved therewith, primary magnetizing inductance LSImprove therewith, so that transformed error ε reductions, enter
One step improves the precision of AC current transformer, so as to solve what the compensation zero-flux current transformer of conditional electronic was present
Reduce the resistance R of load resistanceL, improve multiplication factor A when can cause magnetic permeability μ reduction problem.
Each technical characteristic of embodiment described above can be combined arbitrarily, to make description succinct, not to above-mentioned reality
Apply all possible combination of each technical characteristic in example to be all described, as long as however, the combination of these technical characteristics is not deposited
In contradiction, the scope of this specification record is all considered to be.
Embodiment described above only expresses several embodiments of the invention, and its description is more specific and detailed, but simultaneously
Can not therefore be construed as limiting the scope of the patent.It should be pointed out that coming for one of ordinary skill in the art
Say, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to protection of the invention
Scope.Therefore, the protection domain of patent of the present invention should be determined by the appended claims.
Claims (8)
1. a kind of AC current transformer, it is characterised in that including magnetic core, armature winding, the first secondary windings, second subprime around
Group, multi-gain amplification unit, load elements and auxiliary continuous current excitation circuit；
The armature winding, first secondary windings and the second subprime winding are respectively arranged on the magnetic core；Institute
Armature winding is stated for being connected with circuit-under-test, tested primary current is passed through；Gain described in first level windings in series is put
With the second subprime windings in series after big unit；The second subprime winding is also connected with the load elements；The auxiliary
Continuous current excitation circuit is used to provide continuous current excitation electric current；The continuous current excitation electric current is used to produce magnetic field so that the work of the magnetic core
Make magnetic induction intensity between 4th/to five/5th of the saturation induction density of the magnetic core.
2. AC current transformer according to claim 1, it is characterised in that the auxiliary continuous current excitation circuit includes straight
Stream driving source and assists winding；The DC source of energization forms loop with the assists winding；The assists winding is arranged at
On the magnetic core.
3. AC current transformer according to claim 2, it is characterised in that the DC source of energization swashs for direct current constant current
Encourage source.
4. AC current transformer according to claim 1, it is characterised in that the auxiliary continuous current excitation circuit includes straight
Stream driving source；The DC source of energization and first level winding parallel.
5. AC current transformer according to claim 4, it is characterised in that the DC source of energization swashs for direct current constant current
Encourage source.
6. AC current transformer according to claim 1, it is characterised in that the load elements are load resistance.
7. AC current transformer according to claim 1, it is characterised in that the input of the multi-gain amplification unit with
The first secondary windings connection, the output end of the multi-gain amplification unit is connected with the second subprime winding.
8. according to any described AC current transformer of claim 1~7, it is characterised in that the continuous current excitation electric current is used
Cause that the magnetic core is operated at the maximum position of magnetic conductivity in magnetic field is produced.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410842078.8A CN104576005B (en) | 2014-12-30 | 2014-12-30 | AC current transformer |
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|---|---|---|---|
| CN201410842078.8A CN104576005B (en) | 2014-12-30 | 2014-12-30 | AC current transformer |
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| CN104576005B true CN104576005B (en) | 2017-07-07 |
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| CN106653336B (en) * | 2015-10-29 | 2018-08-14 | 中国电力科学研究院 | A method of preparing the current transformer with simplification error test function |
| CN105785095A (en) * | 2016-04-21 | 2016-07-20 | 中车青岛四方机车车辆股份有限公司 | Constant-amplitude DC pulse signal measurement circuit and degaussing method thereof |
| KR101937209B1 (en) * | 2017-06-09 | 2019-01-10 | 엘에스산전 주식회사 | Apparatus for sensing current |
| CN109754998B (en) * | 2019-03-06 | 2020-07-21 | 陈德才 | Active two-stage current transformer |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| FR2690993A1 (en) * | 1992-05-06 | 1993-11-12 | Europ Agence Spatiale | Galvanically-isolated DC current pulse intensity measurement appts. e.g. for DC=DC converter or radar - has transformer with first sec. in parallel with resistor across which voltage is measured by amplifier, and second transformer sec. which is in series with further resistor and fed by amplifier output. |
| JPH0862254A (en) * | 1994-08-19 | 1996-03-08 | Yaskawa Electric Corp | Direct current detector |
| JP2007109787A (en) * | 2005-10-12 | 2007-04-26 | Mayekawa Mfg Co Ltd | Contactless dc galvanometer |
| JP5257811B2 (en) * | 2008-10-28 | 2013-08-07 | 日本原子力発電株式会社 | Fast response and low current consumption non-contact DC current sensor |
| CN102969136B (en) * | 2012-11-17 | 2015-09-16 | 郑州三晖电气股份有限公司 | A kind of big current, High-accuracy direct current current transformer |
| CN103000361A (en) * | 2012-11-22 | 2013-03-27 | 南京江北自动化技术有限公司 | Current transformer |
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