CN104459265B - The balanced compensated transformer measurement circuit of mutual inductor spurious impedance - Google Patents
The balanced compensated transformer measurement circuit of mutual inductor spurious impedance Download PDFInfo
- Publication number
- CN104459265B CN104459265B CN201410691793.6A CN201410691793A CN104459265B CN 104459265 B CN104459265 B CN 104459265B CN 201410691793 A CN201410691793 A CN 201410691793A CN 104459265 B CN104459265 B CN 104459265B
- Authority
- CN
- China
- Prior art keywords
- mutual inductor
- resistance
- circuit
- operational amplifier
- output
- 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.)
- Active
Links
Abstract
The invention discloses a kind of transformer measurement circuits that mutual inductor spurious impedance is balanced compensated, belong to analog signal measuring circuit technical field.Two output ends of mutual inductor are connected separately with operational amplifier circuit, parallel filtering circuit between the inverting input terminal of each operational amplifier circuit and its output end；And the equivalent resistance R01 and R02 of the output port of the secondary side of resistance R1, R3, R4, R5 and mutual inductor involved in the technical program meet the following conditions：R4/R3=R5/ (R1+R01), R4/R3=R5/ (R1+R02), R01=R02=R0/2, R0 are the secondary side spurious impedance of mutual inductor.At two R5 tie points, apply DC offset voltage Vref, the output Uop and Uon of two amplifiers, zero mutual inductor output loading as of the invention being achieved, using Vref as center voltage, the differential signal directly proportional to mutual inductor secondary current, size and phase accurately reflect the size and phase of mutual inductor primary side current.
Description
Technical field
The present invention relates to analog signal measuring circuit technical fields, more particularly, to the measurement of mutual inductor spurious impedance compensation
Circuit.
Background technique
Modern society, electric power energy are widely used, safety utilization of electric power (circuit protection), fair electricity consumption (accurate metering and billing),
Rational utilization of electricity (energy-saving and emission-reduction) etc., is required to based on accurately measuring the parameters such as electric current.However power generation, power transformation, transmission of electricity,
Size of current great disparity in distribution and the route of electricity consumption has from several peaces to tens of thousands of Andu.To need convenient for measurement, protection and control
The unified electric current of comparison is converted to, in addition the voltage on route is generally relatively high, and such as directly measurement is breakneck, it is necessary to
There is measurement sensing element to be converted to measuring device acceptable weak signal.
The measurement sensing element of electric current, the most commonly used is current transformers, and structure is relatively simple, by the primary of mutually insulated
The composition such as winding, secondary winding, iron core and framework, shell, connecting terminal, easily can be converted to measurement for high current
Equipment acceptable low current signal, and play the role of electrical isolation, it ensure that the safe and reliable steady operation of measuring device.
Furthermore production technology is relatively easy and technology maturation, at low cost, can also accomplish the preferable measurement accuracy that compares, thus extensive
Using.
Current transformer is realized according to electromagnetic induction principle, as the principle of transformer.
Ideal mutual inductor and its measuring circuit, first and second winding is without internal resistance, and iron core is without magnetic resistance, iron core infinite,
The impedance of secondary output is zero, in this way, the energy that primary current generates in mutual inductor, loss-free in the least can pass to secondary
Then there is I1N1=I2n2 namely I2/I1=N1/n2 in side.
However, in practice, this be it is impossible, at least prior art condition is also much not achieved.It is actual for one
Mutual inductor and its measuring circuit, first and second winding has impedance, and (mainly resistance and induction reactance, capacitive reactance can be ignored not completely
Meter), especially secondary winding pricks that number is more, and line footpath is thin, thus spurious impedance is big, and iron core has magnetic resistance and impedance, for instrument mutual inductance
Device, secondary side is often there are also loading, thus actual mutual inductor, there are no small error, including angular difference and ratio it is poor.From
Current transformer generate since, explore by being continually striving to, understand substantially, the error of mutual inductor, substantially by it is following because
Element is constituted：
1, excitation loss and iron loss.Primary side current I1 must have one part of current I01 to magnetize iron core, so that iron core
Middle generation magnetic flux, I01N1 are known as abampere circle or excitation magnetomotive force；Furthermore I1 also has one part of current I02, because magnetic flux passes through
When iron core, vortex is formed in core interior and is consumed, this partition losses, referred to as iron loss.Core material permeability is bigger, required
I01 it is smaller, error is smaller.Iron core resistance is bigger, and inducting, it is smaller to be vortexed, and I02 is smaller, and error is smaller.
2, secondary load size and property.Secondary load, the spurious impedance including secondary winding.Error and secondary load at
Direct ratio, but after load increase, iron-core magnetic induction intensity becomes larger, and magnetic conductivity slightly improves, so error is slightly less than direct ratio increase.
3, the number of turns of secondary winding.Error and secondary winding the number of turns square are inversely proportional.Therefore increase secondary winding the number of turns,
It can be reduced the error of mutual inductor.But it will increase secondary winding internal resistance, secondary circuit total impedance while increasing secondary winding the number of turns
Become larger, adds somewhat to error.
4, the frequency of power grid.Frequency is bigger, and error is bigger, this itself is again related with core characteristics.
5, primary current size.To all it reduce when electric current becomes larger than poor, angular difference.However current variation is very big, it will usually 0
Change between rated current, thus, transformer error is nonlinear.
Due to current transformer material itself and measuring principle influence, the measurement accuracy of current transformer is improved,
Always work of the scientific and technological circle in ongoing effort.The existing technology for improving transformer precision mainly includes --- and research is more preferable
Core material, since the mild steel of early stage, develop for later more clock ferrites, alloy material, powder core material, amorphous and
Nano-crystal soft magnetic alloy etc. technology.These are improved, and are provided to reach several purposes：It improves magnetic conductivity, propose high saturation magnetic induction
Intensity is answered, residual magnetic flux density is reduced, reduces coercive force, improving iron core impedance, a word exactly improves the property of iron core
Energy；Increase core section, shorten the length of magnetic path, makes iron core work under conditions of magnetic induction intensity is not high；Increase coil turn.
Increasing coil ampere-turn can accordingly reduce than difference and angular difference；The influence for limiting secondary load, minimizes secondary load；Design zero magnetic
Logical mutual inductor, sufficiently reducing excitation influences.
Existing mutual inductor exports measuring circuit although being zero load circuit, but be not in fact zero load, because
The spurious impedance R0 of mutual inductor is actual load, cannot be eliminated herein, and the voltage E2 of the output loading of mutual inductor is driven
And it is not zero.Furthermore this circuit is influenced, potentially unstable by amplifier quality.The output of third, mutual inductor is directly connected to
The input of amplifier, amplifier is vulnerable to external interference.
Summary of the invention
For overcome the deficiencies in the prior art, the present invention proposes a kind of mutual inductor measuring that mutual inductor spurious impedance is balanced compensated
Circuit is measured, is exported the purpose is to improve the measurement accuracy of measurement mutual inductor, and for symmetric difference.
In order to solve the above technical problems, basic technical scheme proposed by the present invention is：It is exported for symmetric difference, mutually
Two output ports of sensor are connected separately with operational amplifier circuit, between the inverting input terminal of each operational amplifier circuit and its output end simultaneously
Join filter circuit；
The filter circuit includes the resistance R2 and capacitor C1 being cascaded；
Series resistance R1 between the inverting input terminal of the operational amplifier circuit and the output port of the mutual inductor respectively connected, often
The inverting input terminal of a operational amplifier circuit connect resistance R3, the output end of each operational amplifier circuit and its non-inverting input terminal with its output end
Between be arranged resistance R4；Two resistance R5 are sequentially connected in series between the non-inverting input terminal of two operational amplifier circuits, and in two resistance
An output end is drawn between R5, the output end be direct current offset reference voltage Vref access point, wherein resistance R1, R3, R4, R5 and
The equivalent resistance R01 and R02 of the output port of the secondary side of mutual inductor meet the following conditions：R4/R3=R5/ (R1+R01),
R4/R3=R5/ (R1+R02), R01=R02.
Preferably, in the balanced compensated transformer measurement circuit of the mutual inductor spurious impedance, mutual inductor exports both ends string
It is connected to phase-shift compensation circuit.
Preferably, in the balanced compensated transformer measurement circuit of the mutual inductor spurious impedance, the phase-shift compensation circuit
Including the resistance R7 and capacitor C2 being cascaded.
Preferably, in the balanced compensated transformer measurement circuit of the mutual inductor spurious impedance, the resistance value of the resistance R7
It is 20K~50K ohm, the capacitance of the capacitor C2 is 0.1 μ of μ F~0.3 F.
The beneficial effects of the invention are as follows：
1, the zero load measurement of mutual inductor is really realized, it is only necessary to some energy of very little, it can be primary side
Information, passes to secondary side, this required portion of energy consumes in excitation and iron loss, so as to significantly improve survey
Accuracy of measurement.
It 2, can since the circuits such as capacitance-resistance filter can be increased between mutual inductor output and amplifier relative to existing circuit
To protect amplifier well, so that circuit operation becomes more stable reliably.
3, its size can be arranged in DC offset voltage Vref according to demand, so that the circuit invention can both be applied in list
In power circuit, it can also apply in two-supply circuit, it is flexible in application.
4, circuit is simple, low in cost, and relative to available circuit, actual cost does not almost increase.Increased resistance, each
Including processing charges, it is no more than 3 points of RMB；Relative to Zero flux mutual inductor, increased cost can be ignored not completely
Meter.
5, production is simple, and consistency is good.It is raw for existing circuit board because only simply increasing several capacitance resistance wares
Production. art, these increased circuits, assembly line easy to accomplish, automation production.
6, in technical solution of the present invention, symmetric difference output is proposed as needed, is conducive to specific measuring circuit
It uses.
Detailed description of the invention
Fig. 1 is the circuit diagram of the transformer measurement circuit of the balanced compensated difference output of mutual inductor spurious impedance；
Fig. 2 is the circuit diagram of embodiment two.
Specific embodiment
Below with reference to attached drawing 1 and attached drawing 2, the present invention is described further, but should not be of the invention to limit with this
Protection scope.
Embodiment one：
In the present invention, the secondary side of mutual inductor is equivalent to circuit 10, which includes etc.
Current source I2 and equivalent impedance R0 (R0 is bisected into R01 and R02) is imitated, the electromotive force at the both ends I2 is E2, and E2 is driving mutual inductor two
Voltage needed for secondary lateral load (internal driving including secondary side, i.e. spurious impedance R0).It is connected at the output end c of mutual inductor
There is resistance R1, one operational amplifier circuit of resistance R1 connection, the output end i of the inverting input terminal e of operational amplifier circuit and the operational amplifier circuit is simultaneously
Join resistance R3, resistance R4 is set between the non-inverting input terminal g of operational amplifier circuit and the output end i of operational amplifier circuit, in operational amplifier circuit
A filter circuit also in parallel between inverting input terminal e and its output end i, the filter circuit include the resistance R2 being cascaded and
Capacitor C1.
Specifically, also connect an operational amplifier circuit at the output end d of mutual inductor secondary side equivalent circuit, the operational amplifier circuit with
The operational amplifier circuit being connected at the output end c of mutual inductor is just the same, which is also connected with resistance R2, R3, R4 and filter
Wave circuit.For simple, illustrated with Fig. 1, be exactly circuit be up and down it is symmetrical, upper and lower two parts are duplicate.
In addition, there are two resistance R5, the resistances of two resistance R5 for connection between the non-inverting input terminal of two operational amplifier circuits
It is worth identical, i.e., connects two resistance R5 at the g in figure and between h, and draw an output end k between two resistance R5,
DC offset voltage Vref is accessed at the k.
In the present invention, R01 and R02 are the spurious impedances of mutual inductor, can very easily be measured.In this circuit, two
It is for protecting operational amplifier circuit that a resistance R1, which is added between the output end and operational amplifier circuit of mutual inductor secondary side equivalent circuit,.Electricity
R3, R01, R02 are hindered together with R1, and the secondary side current of mutual inductor is converted into the differential voltage that subsequent conditioning circuit can be used and is believed
Number.And filter circuit is used to filter mutual inductor and is conducted through the high-frequency interferencing signal come.Resistance R4, R5 be used to balanced impedance R01 and
R02, so that the output loading voltage E2 of driving mutual inductor is zero, so that the load of mutual inductor is also zero.
Specifically, these resistance meet the following conditions：
R4/R3=R5/ (R1+R01), R4/R3=R5/ (R1+R02), R01=R02.
According to the empty short empty disconnected feature of amplifier, e (for convenience of explanation, wherein e and g equal with the voltage of h difference with g and f
Between voltage be defined as Ueg, so analogize), Uig=Uie, Ugk=Uea, same Ukh=Ubf, Uhj=Ufj, in this way
So that the E2 of the load voltage of driving mutual inductor is zero.Load voltage E2 is zero, and load is also just zero, to be truly realized zero
Load measure.Meanwhile the relationship between R1, R3, R4, R5 and R01, R02, so that output Uop, Uon of two amplifiers are with k
Point voltage Vref is that the symmetric difference of reference point exports：
Specific Uop-Uon=I2* (R3+R1+R01+R02+R1+R3)+E2=I2* (R3+R1+R01+R02+R1+
R3)。
By the technical program, can the secondary side spurious impedance to mutual inductor compensate, realize the true of mutual inductor
Positive zero load output, improves the measurement accuracy of equipment, while can be realized symmetric difference output, meets the demand of measurement.
Embodiment two：
The present embodiment is compared with embodiment one, and in two output end parallel connection phase-shift compensation circuits of mutual inductor, which includes
Resistance R7 and capacitor C2；Wherein the resistance value of resistance R7 is 30K ohm, and the capacitance of the capacitor C2 is 0.1 μ F.
According to the disclosure and teachings of the above specification, those skilled in the art in the invention can also be to above-mentioned embodiment party
Formula is changed and is modified.Therefore, the invention is not limited to the specific embodiments disclosed and described above, to of the invention
Some modifications and changes should also be as falling into the scope of the claims of the present invention.In addition, although being used in this specification
Some specific terms, these terms are merely for convenience of description, does not limit the present invention in any way.
Claims (4)
1. a kind of transformer measurement circuit that mutual inductor spurious impedance is balanced compensated is exported for symmetric difference, it is characterised in that：
Two output ports of mutual inductor are connected separately with operational amplifier circuit, between the inverting input terminal of each operational amplifier circuit and its output end
Parallel filtering circuit,
The filter circuit includes the resistance R2 and capacitor C1 being cascaded；
Series resistance R1, Mei Geyun between the inverting input terminal of the operational amplifier circuit and the output port of the mutual inductor respectively connected
The inverting input terminal on electric discharge road connect resistance R3 with its output end, between the output end of each operational amplifier circuit and its non-inverting input terminal
Resistance R4 is set；Be sequentially connected in series two resistance R5 between the non-inverting input terminal of two operational amplifier circuits, and two resistance R5 it
Between draw an output end, the output end be direct current offset reference voltage Vref access point, wherein resistance R1, R3, R4, R5 and mutual inductance
The equivalent resistance R01 and R02 of the output port of the secondary side of device meet the following conditions：R4/R3=R5/ (R1+R01), R4/R3=
R5/ (R1+R02), R01=R02.
2. the balanced compensated transformer measurement circuit of mutual inductor spurious impedance as described in claim 1, it is characterised in that：Mutual inductance
Device output both ends are serially connected with phase-shift compensation circuit.
3. the balanced compensated transformer measurement circuit of mutual inductor spurious impedance as claimed in claim 2, it is characterised in that：It is described
Phase-shift compensation circuit includes the resistance R7 and capacitor C2 being cascaded.
4. the balanced compensated transformer measurement circuit of mutual inductor spurious impedance as claimed in claim 3, it is characterised in that：It is described
The resistance value of resistance R7 is 20K~50K ohm, and the capacitance of the capacitor C2 is 0.1 μ of μ F~0.3 F.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410691793.6A CN104459265B (en) | 2014-11-26 | 2014-11-26 | The balanced compensated transformer measurement circuit of mutual inductor spurious impedance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410691793.6A CN104459265B (en) | 2014-11-26 | 2014-11-26 | The balanced compensated transformer measurement circuit of mutual inductor spurious impedance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104459265A CN104459265A (en) | 2015-03-25 |
| CN104459265B true CN104459265B (en) | 2018-11-30 |
Family
ID=52905647
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410691793.6A Active CN104459265B (en) | 2014-11-26 | 2014-11-26 | The balanced compensated transformer measurement circuit of mutual inductor spurious impedance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104459265B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112433130B (en) * | 2020-11-05 | 2023-03-21 | 国网重庆市电力公司电力科学研究院 | Equivalent impedance control-based alternating current withstand voltage test method for electromagnetic voltage transformer |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7525297B2 (en) * | 2005-12-01 | 2009-04-28 | Falco Ltd. | Current transformer with impedance compensation and associated methods |
| CN101086917A (en) * | 2006-06-09 | 2007-12-12 | 郑州大学 | Compensation method of voltage mutual inductor and secondary loop voltage reduction error and compensation device |
| CN102682985B (en) * | 2012-05-16 | 2015-04-22 | 深圳市深泰明科技有限公司 | High-voltage electronic type voltage transformer |
| CN103928226A (en) * | 2013-01-14 | 2014-07-16 | 上海浦东金盛互感器厂 | Error compensation single-core three-winding current transformer and split core type current transformer |
| CN103941065B (en) * | 2013-01-17 | 2017-05-03 | 上海浦东金盛互感器厂 | Method used for reducing residual impedance effect of voltage transformer and inductive voltage divider primary winding |
| CN203590195U (en) * | 2013-12-10 | 2014-05-07 | 中国石油化工股份有限公司 | Improved simulation integrating circuit based on PCB Rogowski coil current transformer |
| CN203838223U (en) * | 2014-03-28 | 2014-09-17 | 云南电力试验研究院（集团）有限公司电力研究院 | Hall current transformer |
-
2014
- 2014-11-26 CN CN201410691793.6A patent/CN104459265B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN104459265A (en) | 2015-03-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102841258B (en) | Measuring device and method for direct current supply output impedance | |
| CN103575960B (en) | giant magnetoresistance effect current sensor | |
| CN202837406U (en) | DC power supply output impedance measuring device | |
| CN202886483U (en) | Low-frequency large-capacitance measuring device | |
| CN103207379B (en) | Method and device for measuring direct current magnetic bias error characteristics of current transformer | |
| CN100501415C (en) | Highly anti-interference alternating-current/magnetic field sensor | |
| CN203590195U (en) | Improved simulation integrating circuit based on PCB Rogowski coil current transformer | |
| CN101872005B (en) | Electronic periodic non-sinusoidal wave reference current transformer with current booster | |
| CN110658374A (en) | Current transformer with wide frequency, wide measurement and anti-magnetic interference capability | |
| CN103592490A (en) | High-accuracy electronic compensated current transformer | |
| CN105606963A (en) | Test circuit for measuring high-frequency leakage current of cable | |
| CN104851580B (en) | Gapped core-type Rogowski coil transformer based on magnetic potentiometer compensation | |
| CN106053909B (en) | Electric resistance partial pressure type three-phase combination voltage mutual inductor with residual voltage output | |
| CN104374979A (en) | Digital alternating current resistance electrical bridge | |
| CN203535102U (en) | Colossal magnetoresistance effect current sensor | |
| CN109782062A (en) | A kind of Rogowski coil type electronic current mutual inductor harmonic wave meter characteristic optimization method | |
| CN104459265B (en) | The balanced compensated transformer measurement circuit of mutual inductor spurious impedance | |
| CN203606413U (en) | High-accuracy electronic compensation type current transformer | |
| CN103941065A (en) | Method used for reducing residual impedance effect of voltage transformer and inductive voltage divider primary winding | |
| CN106653339B (en) | Current transformer | |
| CN101872006B (en) | Periodic non-sinusoidal wave reference of electronic voltage transformer with voltage booster | |
| CN204464036U (en) | Based on the band gap iron core type Luo-coil instrument transformer that magnetic potentiometer compensates | |
| CN201053988Y (en) | Highly antijamming AC current/ magnetic field sensor | |
| CN104459596B (en) | The balanced compensated transformer measurement circuit of mutual inductor spurious impedance | |
| CN204666709U (en) | Half magnetic core current sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |