CN115951107A - Current detection device - Google Patents
Current detection device Download PDFInfo
- Publication number
- CN115951107A CN115951107A CN202310035321.4A CN202310035321A CN115951107A CN 115951107 A CN115951107 A CN 115951107A CN 202310035321 A CN202310035321 A CN 202310035321A CN 115951107 A CN115951107 A CN 115951107A
- Authority
- CN
- China
- Prior art keywords
- winding
- magnetic core
- output
- primary winding
- amplifier
- 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.)
- Pending
Links
Images
Abstract
An embodiment of the present specification provides a current detection apparatus, including: the transformer comprises a first transformer, a second transformer, a third transformer, a first amplifier, a second amplifier and a third amplifier, wherein the first transformer comprises a first primary winding, a first secondary winding, a first magnetic core and a magnetoelectric converter; the second primary winding and the third primary winding, the second secondary winding and the third secondary winding, and the first output winding and the second output winding are reversely wound. The problem that the coupled high-frequency current cannot be measured under the background of large direct current is solved.
Description
Technical Field
This document relates to current detection technical field, especially relates to a current detection device.
Background
Signals in nature generally have the characteristics of higher frequency and smaller amplitude, so that the signals at the higher frequency need a measuring device with higher sensitivity.
The current commonly used direct current measuring method comprises two methods of resistance current measurement and Hall current sensor current measurement, pure alternating current signals can adopt a CT or Rogowski coil mode, the four schemes are simpler, but the defects are also obvious:
the resistance current measuring method has the advantages of simplicity and relatively low cost, and has the defects that the resistance consumes power, the resistance consumes more power in a heavy-current situation, the resistance has large volume, the frequency band range is influenced by the bandwidth and the amplification factor of the operational amplifier, the input and the output are not isolated, and the resistance current measuring method can be generally only applied to a low-voltage non-isolated situation;
the Hall current sensor current measuring method has the advantages of primary and secondary isolation, wide current amplitude range (5-100A level), and low signal sensitivity (higher than 1 mV) and bandwidth (less than 400 Khz). In some application occasions (arc measurement), the tiny current characteristic of a high-frequency signal needs to be tested, and at this time, a resistance current measuring scheme and a Hall current sensor scheme cannot be realized;
the CT scheme applies an electrorheological current principle in a transformer, requires a resistor for current-voltage conversion, and requires amplification processing of operational amplifier, so that the bandwidth and sensitivity are low;
the rogowski coil is also an air core coil, but the current is obtained by adopting an integral mode, so that the measurement is only specific to a certain frequency point, and the rogowski coil is only used for testing large current, and small signals cannot be measured.
Current probes sold on the market currently can detect 100MHz, the sensitivity is more than 1mV, but signals of uV level cannot be measured.
Disclosure of Invention
One or more embodiments of the present specification provide a current detection apparatus, including a first transformer, a second transformer, a third transformer, a first amplifier 205, a second amplifier 206, and a third amplifier 502, where the first transformer includes a first primary winding 202, a first secondary winding 203, a first magnetic core 201, and a magnetoelectric converter 204, the second transformer includes a second primary winding 302, a second secondary winding 303, and a second magnetic core 301, the third transformer includes a third primary winding 402, a third secondary winding 403, and a third magnetic core 401, the second magnetic core 301 and the third magnetic core 401 are closely stacked, the second magnetic core 301 is further wound with a first output winding 304, and the third magnetic core 401 is further wound with a second output winding 404;
the magnetoelectric converter 204 is mounted in the first magnetic core 201 through a slit in the first magnetic core 201, and an output terminal of the magnetoelectric converter 204 is connected to an input terminal of the first amplifier 205; the first primary winding 202, the second primary winding 302 and the third primary winding 402 are sequentially connected in series between a first input end and a second input end of the current detection circuit, the first secondary winding 203 is connected in series between an output end of the first amplifier 205 and an inverting input end of the second amplifier 206, an output end of the second amplifier 206 outputs a low-frequency current signal to a non-inverting input end of the third amplifier 502, the third secondary winding 403 and the second secondary winding 303 are sequentially connected in series between an output end of the third amplifier 502 and an output end of the current detection circuit, and the first output winding 304 and the second output winding 404 are connected in series and output a high-frequency current signal;
the primary, secondary and output windings of the second and third magnetic cores 301, 401 are all wound in series and in reverse direction.
Further, the number of turns of the second primary winding 302 is the same as that of the third primary winding 402.
Further, the number of turns of the second secondary winding 303 is the same as that of the third secondary winding 403.
Further, the first output winding 304 and the second output winding 404 have the same number of turns.
Further, the number of turns of the first primary winding 202, the second primary winding 302 and the third primary winding 402 is one turn.
Further, the number of turns of the first primary winding 202, the second primary winding 302 and the third primary winding 402 is multiple.
Further, the number of turns of the second secondary winding 303 and the third secondary winding 403 is set according to the relationship between the low-frequency output signal and the current to be detected.
Further, the high-frequency current signal is connected with a conditioning circuit, and the conditioning circuit is used for restoring the nonlinearity amplitude of the high-frequency current signal to linearity.
Further, the conditioning circuit includes an amplification circuit.
Further, the conditioning circuit includes an amplifying circuit and an integrating circuit.
The invention has the following beneficial effects:
the bandwidth is large, and signals of 1MHz can be measured; the sensitivity to high-frequency signals is high, the high-frequency current signals are automatically multiplied by the angular frequency omega of the signals, the amplitude of the high-frequency signals is amplified, and the signal-to-noise ratio during signal sampling is improved; the method can directly measure the high-frequency small signal under the direct current coupling, and solves the problem that the coupled high-frequency current under the background of large direct current cannot be measured.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
In order to more clearly illustrate one or more embodiments or prior art solutions of the present specification, the drawings that are needed in the description of the embodiments or prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present specification, and that other drawings can be obtained by those skilled in the art without inventive exercise.
Fig. 1 is a schematic structural diagram of a current detection device according to one or more embodiments of the present disclosure;
fig. 2 is a schematic diagram of a current-to-voltage converter of a current detection device according to one or more embodiments of the present disclosure;
fig. 3 is a schematic structural diagram of a high-frequency current signal conditioning circuit of a current detection device according to one or more embodiments of the present disclosure.
201: a first magnetic core; 202: a first primary winding; 203: a first primary winding; 204: a magnetoelectric converter; 205: a first amplifier; 206: a second amplifier; 301: a second magnetic core; 302: a second primary winding; 303: a second secondary winding; 304: a first output winding; 401: a third magnetic core; 402: a third primary winding; 403: a third secondary winding; 404: a second output winding; 502: and a third amplifier.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in one or more embodiments of the present disclosure, the technical solutions in one or more embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in one or more embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all embodiments. All other embodiments that can be derived by a person skilled in the art from one or more of the embodiments described herein without making any inventive step shall fall within the scope of protection of this document.
The invention provides a current detection device, fig. 1 is a schematic structural diagram of a current detection device provided in one or more embodiments of the present specification, as shown in fig. 1, a structure 1 is a basic principle circuit of a hall current sensor, and based on the basic principle circuit of the hall current sensor, the current detection device of the embodiment of the present invention includes a structure 1 and a structure 2:
the magnetic core type transformer specifically comprises a first transformer, a second transformer, a third transformer, a first amplifier 205, a second amplifier 206 and a third amplifier 502, wherein the first transformer comprises a first primary winding 202, a first secondary winding 203, a first magnetic core 201 and a magnetoelectric converter 204, the second transformer comprises a second primary winding 302, a second secondary winding 303 and a second magnetic core 301, the third transformer comprises a third primary winding 402, a third secondary winding 403 and a third magnetic core 401, the second magnetic core 301 and the third magnetic core 401 are tightly stacked, a first output winding 304 is wound on the second magnetic core 301, and a second output winding 404 is wound on the third magnetic core 401; therefore, the structure 2 is a stack of two current-to-voltage converters, the principle of which is shown in fig. 2, the primary winding and the secondary winding are wound on the magnetic core, and assuming that the current i (t) = Asin (ω t) of the primary winding, the relationship between the current i (t) of the primary winding and the voltage u (t) of the secondary winding is shown in formula 1:
wherein M is the mutual inductance of the primary coil and the secondary coil; mu.s 0 Magnetic permeability value, μ, for vacuum 0 ＝4π×10 -7 ；μ r Is the relative permeability of air, mu r Has a value of 1; omega is the angular frequency of the signal; MPL is the magnetic path length of the current-voltage converter, and the circular winding magnetic path length as shown in fig. 2 is MPL =2 tr.
From equation 1, it can be seen that the frequency-dependent relationship, in which the amplitude value of u (t) increases in proportion to the angular frequency ω of the signal, provides great convenience for sampling high-frequency signals.
In fig. 1, the magnetoelectric converter 204 is mounted in the first magnetic core 201 through a gap in the first magnetic core 201, and the output terminal of the magnetoelectric converter 204 is connected to the input terminal of the first amplifier 205; the first primary winding 202, the second primary winding 302 and the third primary winding 402 are sequentially connected in series between a first input end and a second input end of the current detection circuit, the first secondary winding 203 is connected in series between an output end of the first amplifier 205 and an inverting input end of the second amplifier 206, an output end of the second amplifier 206 outputs a low-frequency current signal Vout1 to a non-inverting input end of the third amplifier 502, the third secondary winding 403 and the second secondary winding 303 are sequentially connected in series between an output end of the third amplifier 502 and an output end of the current detection circuit, a voltage signal output by the structure 1 is converted into a current for offsetting the second magnetic core 301 and the third magnetic core 401 through the third amplifier 502, the first output winding 304 and the second output winding 404 are connected in series, and a high-frequency current signal Vout2 is output;
the primary windings, the secondary windings and the output windings of the second magnetic core 301 and the third magnetic core 401 are all wound in series and reversely, so that the structure 2 injects low-frequency components, particularly direct-current components, in the current signals collected by the structure 1 into the second magnetic core 301 and the third magnetic core 401 again in a reverse direction, and offsets magnetic flux bias generated by direct current so as to ensure that the magnetic flux of high-frequency signals is near 0 gauss, thereby improving the accuracy of high-frequency signal collection, and meanwhile, electromagnetic interference signals received by the second magnetic core 301 and the second magnetic core 401 are offset when the first output winding 304 and the second output winding 404 are superposed in series, so that the signal-to-noise ratio (SNR) of the signals is enhanced, and the quality of the signals is improved.
In addition, in the present embodiment, the number of turns of the second primary winding 302 is the same as that of the third primary winding 402; the number of turns of the second secondary winding 303 is the same as that of the third secondary winding 403; the first output winding 304 has the same number of turns as the second output winding 404; the number of turns in the first primary winding 202, the second primary winding 302, and the third primary winding 402 may be one or more turns; the number of turns of the second secondary winding 303 and the third secondary winding 403 is set according to the relationship between the low-frequency output signal Vout1 and the current i (t) to be detected. Assuming that the detection current of the structure 1 is i (t) =1A, and the operational output voltage of the second amplifier 206 is (Vref + k) V, the relationship between R3, R4 and R2 in fig. 1 is shown in formula 2:
where N is the number of turns in the 303 and 403 windings.
The first output winding 304 and the second output winding 404 are connected in series, and the output high-frequency current signal Vout2 is not linear in signal amplitude because it is fixedly multiplied by the angular frequency ω of the signal. If the linearity is to be recovered, the nonlinear amplitude of the high-frequency current signal can be recovered by conditioning through a signal conditioning circuit, which is shown in fig. 3 and comprises inputting a high-frequency current signal Vout2 into an amplifying circuit or conditioning the high-frequency current signal Vout2 through an amplifying circuit and an integrating circuit in sequence, and outputting a high-frequency current signal Vout3.
The invention has the following beneficial effects:
the bandwidth is large, and signals of 1MHz can be measured; the sensitivity to high-frequency signals is high, the high-frequency current signals are automatically multiplied by the angular frequency omega of the signals, the amplitude of the high-frequency signals is amplified, and the signal to noise ratio during signal sampling is improved; the method can directly measure the high-frequency small signal under the direct current coupling, and solves the problem that the coupled high-frequency current under the background of large direct current cannot be measured.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A current detection device is characterized in that,
the magnetic core comprises a first transformer, a second transformer, a third transformer, a first amplifier 205, a second amplifier 206 and a third amplifier 502, wherein the first transformer comprises a first primary winding 202, a first secondary winding 203, a first magnetic core 201 and a magnetoelectric converter 204, the second transformer comprises a second primary winding 302, a second secondary winding 303 and a second magnetic core 301, the third transformer comprises a third primary winding 402, a third secondary winding 403 and a third magnetic core 401, the second magnetic core 301 and the third magnetic core 401 are tightly stacked, a first output winding 304 is wound on the second magnetic core 301, and a second output winding 404 is wound on the third magnetic core 401;
the magnetoelectric converter 204 is mounted in the first magnetic core 201 through a slit in the first magnetic core 201, and an output terminal of the magnetoelectric converter 204 is connected to an input terminal of the first amplifier 205; the first primary winding 202, the second primary winding 302 and the third primary winding 402 are sequentially connected in series between a first input end and a second input end of the current detection circuit, the first secondary winding 203 is connected in series between an output end of the first amplifier 205 and an inverting input end of the second amplifier 206, an output end of the second amplifier 206 outputs a low-frequency current signal to a non-inverting input end of the third amplifier 502, the third secondary winding 403 and the second secondary winding 303 are sequentially connected in series between an output end of the third amplifier 502 and an output end of the current detection circuit, and the first output winding 304 and the second output winding 404 are connected in series to output a high-frequency current signal;
the primary winding, the secondary winding and the output winding of the second magnetic core 301 and the third magnetic core 401 are all wound in series and reversely.
2. The apparatus of claim 1 wherein the second primary winding 302 has the same number of turns as the third primary winding 402.
3. The apparatus of claim 1, wherein the second secondary winding 303 has the same number of turns as the third secondary winding 403.
4. The apparatus of claim 1, wherein the first output winding 304 has the same number of turns as the second output winding 404.
5. The apparatus of claim 1, wherein the first primary winding 202, the second primary winding 302, and the third primary winding 402 have one turn.
6. The apparatus of claim 1, wherein the first primary winding 202, the second primary winding 302, and the third primary winding 402 have a plurality of turns.
7. The apparatus according to claim 1, wherein the number of turns of the second secondary winding 303 and the third secondary winding 403 is set according to the relationship between the low frequency output signal and the current to be detected.
8. The apparatus of claim 1, wherein the high frequency current signal is coupled to a conditioning circuit, the conditioning circuit configured to restore linearity to a non-linear amplitude of the high frequency current signal.
9. The apparatus of claim 8, wherein the conditioning circuit comprises an amplification circuit.
10. The apparatus of claim 8, wherein the conditioning circuit comprises an amplification circuit and an integration circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310035321.4A CN115951107A (en) | 2023-01-10 | 2023-01-10 | Current detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310035321.4A CN115951107A (en) | 2023-01-10 | 2023-01-10 | Current detection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115951107A true CN115951107A (en) | 2023-04-11 |
Family
ID=87296722
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310035321.4A Pending CN115951107A (en) | 2023-01-10 | 2023-01-10 | Current detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115951107A (en) |
-
2023
- 2023-01-10 CN CN202310035321.4A patent/CN115951107A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9442139B2 (en) | Rogowski coil assembly | |
| CN101438173B (en) | Current sensing circuit for use in a current measurement probe | |
| CN110988430B (en) | Fluxgate heavy current sensor based on digital second harmonic detection and ripple compensation | |
| Yang et al. | A giant magneto resistive (GMR) effect based current sensor with a toroidal magnetic core as flux concentrator and closed-loop configuration | |
| US11863033B2 (en) | Displacement detection circuit of maglev rotor system and displacement self-sensing system thereof | |
| US20200249258A1 (en) | Sensor apparatus for measuring direct and alternating currents | |
| Yang et al. | A new compact fluxgate current sensor for AC and DC application | |
| CN103884887A (en) | Isolation circuit having Hall element and oscilloscope of isolation circuit | |
| CN116087604A (en) | Single-ring differential type fluxgate current sensor | |
| CN205826736U (en) | A kind of high accuracy single-turn cored structure formula electric current Online Transaction Processing | |
| CN105510673B (en) | A kind of direct current measuring devices | |
| CN110824229A (en) | Single-magnetic-core multi-winding magnetic balance type current detection device | |
| US20220252642A1 (en) | Current Sensors Employing Rogowski Coils And Methods Of Using Same | |
| US20240036080A1 (en) | Analog quantity acquisition method and apparatus | |
| US20220334146A1 (en) | Closed Loop Current Transformer | |
| CN115951107A (en) | Current detection device | |
| CN105807117B (en) | Current sensing circuit for current measuring probe and current measuring probe thereof | |
| CN1731194A (en) | Differential Rogowski coil for steep pulse small current measurement | |
| CN107942124B (en) | Direct current comparison measuring device | |
| CN113189384A (en) | Ripple current compensation method for sampling resistor of fluxgate current sensor | |
| Xiaohua et al. | Improved performance Rogowski coils for power system | |
| CN114280350B (en) | High-precision current sensor and shunt-based high-current measurement method | |
| CN117233826B (en) | Beam current value measuring circuit | |
| CN116148515A (en) | Low-current signal measuring device and method under direct-current coupling condition | |
| CN114460351A (en) | Current-voltage conversion circuit |
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 |