CN204008813U - A kind of magnetic modulation type current transformer - Google Patents
A kind of magnetic modulation type current transformer Download PDFInfo
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- CN204008813U CN204008813U CN201420410337.5U CN201420410337U CN204008813U CN 204008813 U CN204008813 U CN 204008813U CN 201420410337 U CN201420410337 U CN 201420410337U CN 204008813 U CN204008813 U CN 204008813U
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Abstract
The utility model relates to mutual inductor technical field, especially a kind of magnetic modulation type current transformer.It comprises magnetic core, square-wave voltage source exciting circuit, square wave effective value difference circuit, zeroing circuit and integrating circuit, on described magnetic core, be formed with and detect winding and feedback winding, described detection winding is connected with square-wave voltage source exciting circuit, described feedback winding is connected with integrating circuit, and described square wave effective value difference circuit and zeroing circuit are connected between square-wave voltage source exciting circuit and integrating circuit successively.The utlity model has and detect winding and electromagnetism winding, by the improvement to each circuit, make mutual inductor have the advantages that measuring error is little, measuring accuracy is high simultaneously, can measure fast and effectively straight-flow system, can meet the detection of DC system earth fault; It is simple in structure, has very strong practicality.
Description
Technical field
The utility model relates to mutual inductor technical field, especially a kind of magnetic modulation type current transformer.
Background technology
Generating plant, transformer station direct current system are the working powers of control and signal system, relay protection and aut.eq., and straight-flow system can stable operation directly affects the safe operation of generating plant, transformer station.Grounding is one of common fault of straight-flow system, if can not find in time and repair, just may cause the maloperation of relay protection, telltale, isolating switch, even causes serious converting station electric power accident.For direct current, leak the most common device using when electrometric mutual inductor is Design of DC System Grounding Fault Detection; Existing direct current instrument transformer is generally divided into Hall current mutual inductor and magnetic modulating current mutual inductor; Wherein, Hall current mutual inductor is very easily subject to the interference of extraneous large current field, easily produces remanent magnetism, easy temperature influence, and comparatively speaking, magnetic modulating current mutual inductor is relatively applicable to the detection of straight-flow system; Yet existing magnetic modulating current mutual inductor mostly be take frequency multiplication magnetic modulator as core and conventionally had bimag, there is complex structure, signal circuit and detect the shortcomings such as error is large in it.
Utility model content
For above-mentioned the deficiencies in the prior art, the purpose of this utility model be to provide a kind of circuit structure simple, by detecting winding and feedback winding forms, measuring error is little, measuring accuracy is high magnetic modulation type current transformer.
To achieve these goals, the utility model adopts following technical scheme:
A kind of magnetic modulation type current transformer, it comprises magnetic core, square-wave voltage source exciting circuit, square wave effective value difference circuit, zeroing circuit and integrating circuit, on described magnetic core, be formed with and detect winding and feedback winding, described detection winding is connected with square-wave voltage source exciting circuit, described feedback winding is connected with integrating circuit, and described square wave effective value difference circuit and zeroing circuit are connected between square-wave voltage source exciting circuit and integrating circuit successively.
Preferably, described square-wave voltage source exciting circuit comprises the first operational amplifier, former resistance, the first resistance, the second resistance and the 3rd resistance, the end of oppisite phase of described the first operational amplifier and in-phase end be connected in by the 3rd resistance and the second resistance respectively and detect the two ends of winding, respectively by former resistance and the first resistance eutral grounding, the output terminal of described the first operational amplifier is connected with square wave effective value difference circuit by the 4th resistance, and one end of described the 4th resistance is also by the first diode and the second diode ground connection of series connection.
Preferably, described square wave effective value difference circuit comprises the second operational amplifier, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the second electric capacity and the 3rd electric capacity, the end of oppisite phase of described the second operational amplifier is by the 6th resistance of connecting successively, the 5th resistance is connected with the output terminal of square-wave voltage source exciting circuit, the end of oppisite phase of described the second operational amplifier is by series connection the second capacity earth, in-phase end is by connecting the 7th resistance eutral grounding being connected with output terminal by the 8th resistance, the output terminal of described the second operational amplifier is also connected between the 5th resistance and the 6th resistance by the 3rd electric capacity, the output terminal of described the second operational amplifier is connected with zeroing circuit.
Preferably, described zeroing circuit comprises the 3rd operational amplifier, the tenth resistance, the 13 resistance, the 6th electric capacity and adjustable resistance, described the 13 resistance and the 6th electric capacity are parallel to respectively between the end of oppisite phase and output terminal of the 3rd operational amplifier, and the end of oppisite phase of described the 3rd operational amplifier is also connected with adjustable resistance, in-phase end connects square wave effective value difference circuit by the tenth resistance output terminal, output terminal are connected with integrating circuit.
Preferably, described integrating circuit comprises four-operational amplifier, the 14 resistance, the 5th electric capacity and the 8th electric capacity, the end of oppisite phase of described four-operational amplifier is connected with the output terminal of zero-regulator resistor by the 14 resistance, described the 5th electric capacity is connected between the end of oppisite phase and output terminal of four-operational amplifier, the in-phase end ground connection of described four-operational amplifier, output terminal are by the 8th capacity earth, and the output terminal of described four-operational amplifier connects feedback winding.
Owing to having adopted such scheme, the utlity model has and detect winding and electromagnetism winding, by the improvement to each circuit, make mutual inductor have the advantages that measuring error is little, measuring accuracy is high simultaneously, straight-flow system can be measured fast and effectively, the detection of DC system earth fault can be met; It is simple in structure, has very strong practicality.
Accompanying drawing explanation
Fig. 1 is the circuit system structure figure of the utility model embodiment;
Fig. 2 is the circuit structure diagram of the square-wave voltage source exciting circuit of the utility model embodiment;
Fig. 3 is the circuit structure diagram of the square wave effective value difference circuit of the utility model embodiment;
Fig. 4 is the zeroing circuit of the utility model embodiment and the circuit connection diagram of integrating circuit.
Embodiment
Below in conjunction with accompanying drawing, embodiment of the present utility model is elaborated, but the multitude of different ways that the utility model can be defined by the claims and cover is implemented.
As shown in Figure 1 and in conjunction with Fig. 2 to Fig. 4, the magnetic modulation type current transformer of the present embodiment, it comprises magnetic core 1, square-wave voltage source exciting circuit 2, square wave effective value difference circuit 3, zeroing circuit 4 and integrating circuit 5, on magnetic core 1, be formed with and detect winding W1 and feedback winding W2, detecting winding W1 is connected with square-wave voltage source exciting circuit 2, feedback winding W2 is connected with integrating circuit 5, and square wave effective value difference circuit 3 and zeroing circuit 4 are connected between square-wave voltage source exciting circuit 2 and integrating circuit 5 successively.While having DC magnetic biasing in magnetic core 1, detect winding W1 and can obtain an induction electromotive force, through square-wave voltage source exciting circuit 2, will obtain an asymmetric distorted waveform of positive and negative half-wave, by square wave effective value difference circuit 3, after being processed, distorted waveform obtains positive and negative differential root-mean-square of half waves, send into zeroing circuit 4 and integrating circuit 5, form a voltage potential at the two ends of feedback winding W2.The magnetic bias magnetic potential producing with tested direct current producing by feedback winding W2, has formed zero magnetic flux state.And also can regulate the ratio of final output voltage and input current by regulating the enlargement factor of the operational amplifier in each circuit simultaneously, increased the rapidity of measuring accuracy and reaction.
As shown in Figure 2, the square-wave voltage source exciting circuit of the present embodiment comprises the first operational amplifier U1, former resistance R 0, the first resistance R 1, the second resistance R 2 and the 3rd resistance R 3; Wherein, the end of oppisite phase of the first operational amplifier U1 and in-phase end be connected in by the 3rd resistance R 3 and the second resistance R 2 respectively and detect the two ends of winding W1, respectively by former resistance R 0 and the first resistance R 1 ground connection, the output terminal of the first operational amplifier U1 is connected with square wave effective value difference circuit 3 by the 4th resistance R 4, and one end of the 4th resistance R 4 is also by the first diode Z1 and the second diode Z2 ground connection of series connection.So, the end of oppisite phase that is crimped onto the first operational amplifier U1 that divides from magnetic core 1 signal 1# out through the 3rd resistance R 3 and former resistance R 0, when the input voltage of end of oppisite phase is greater than in-phase end input voltage, the first operational amplifier U1 output low level, on the contrary high level exported, so repeatedly, form a positive and negative square wave, when having DC magnetic biasing, the positive and negative of square wave changes than regular meeting, thereby obtains distorted waveform.
As shown in Figure 3, the square wave effective value difference circuit 3 of the present embodiment comprises the second operational amplifier U2, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 8th resistance R 8, the second capacitor C 2 and the 3rd capacitor C 3; Wherein, the end of oppisite phase of the second operational amplifier U2 is connected with the output terminal of square-wave voltage source exciting circuit 2 by the 6th resistance R 6, the 5th resistance R 5 of connecting successively, the end of oppisite phase of the second operational amplifier U2 by second capacitor C 2 ground connection of connecting, in-phase end by connecting the 7th resistance R 7 ground connection being connected with output terminal by the 8th resistance R 8, the output terminal of the second operational amplifier U2 is also connected between the 5th resistance R 5 and the 6th resistance R 6 by the 3rd capacitor C 3, and the output terminal of the second operational amplifier U2 is connected with zeroing circuit 4.So, when having DC magnetic biasing to occur, square-wave voltage source exciting circuit 2 changes the dutycycle of square wave, because square-wave signal is comprised of direct current signal and some harmonic signals, if use the RC type filtering circuit being formed by the 6th resistance R 6 and the second capacitor C 2 to remove harmonic signal, can obtain d. c. voltage signal.
As shown in Figure 4, the zeroing circuit 4 of the present embodiment comprises the 3rd operational amplifier U3, the tenth resistance R the 10, the 13 resistance R 13, the 6th capacitor C 6 and adjustable resistance R11; Wherein, the 13 resistance R 13 and the 6th capacitor C 6 are parallel to respectively between the end of oppisite phase and output terminal of the 3rd operational amplifier U3, and the end of oppisite phase of the 3rd operational amplifier U3 is also connected with adjustable resistance R11, in-phase end connects square wave effective value difference circuit 3 by the tenth resistance R 10 output terminal, output terminal are connected with integrating circuit 5.The integrating circuit 5 of the present embodiment comprises four-operational amplifier U4, the 14 resistance R 14, the 5th capacitor C 5 and the 8th capacitor C 8, the end of oppisite phase of four-operational amplifier U4 is connected with the output terminal of zero-regulator resistor 4 by the 14 resistance R 14, the 5th capacitor C 5 is connected between the end of oppisite phase and output terminal of four-operational amplifier U4, the in-phase end ground connection of four-operational amplifier U4, output terminal are by the 8th capacitor C 8 ground connection, and the output terminal of four-operational amplifier U4 connects feedback winding W2.The measure of precision that can greatly improve whole mutual inductor by the zeroing circuit 4 arranging, falls within the acceptable range the voltage signal deviate converting to; As shown in Figure 4, in the situation that there is no DC magnetic biasing, by regulating adjustable resistance R11, output voltage U 0 is adjusted to 0V; Also can be by the transmission ratio of the tenth resistance R 10 and the 13 resistance R 13 regulation voltages.Voltage through zeroing circuit 4 zooms into output signal (being feedback signal) through an integrating circuit 5, this signal is connected on the two ends of feedback winding W2, can on feedback winding W2, form an anti-phase direct current magnetic potential with the tested direct current magnetic potential of balance, and in the integrating circuit 5 being formed by the 14 resistance R 14 and the 5th capacitor C 5 etc., the 8th capacitor C 8 has played the effect of filtering, is conducive to strengthen the reaction velocity of mutual inductor.
The foregoing is only preferred embodiment of the present utility model; not thereby limit the scope of the claims of the present utility model; every equivalent structure or conversion of equivalent flow process that utilizes the utility model instructions and accompanying drawing content to do; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present utility model.
Claims (5)
1. a magnetic modulation type current transformer, it is characterized in that: it comprises magnetic core, square-wave voltage source exciting circuit, square wave effective value difference circuit, zeroing circuit and integrating circuit, on described magnetic core, be formed with and detect winding and feedback winding, described detection winding is connected with square-wave voltage source exciting circuit, described feedback winding is connected with integrating circuit, and described square wave effective value difference circuit and zeroing circuit are connected between square-wave voltage source exciting circuit and integrating circuit successively.
2. a kind of magnetic modulation type current transformer as claimed in claim 1, it is characterized in that: described square-wave voltage source exciting circuit comprises the first operational amplifier, former resistance, the first resistance, the second resistance and the 3rd resistance, the end of oppisite phase of described the first operational amplifier and in-phase end are connected in by the 3rd resistance and the second resistance the two ends of detecting winding respectively, respectively by former resistance and the first resistance eutral grounding, the output terminal of described the first operational amplifier is connected with square wave effective value difference circuit by the 4th resistance, one end of described the 4th resistance is also by the first diode and the second diode ground connection of series connection.
3. a kind of magnetic modulation type current transformer as claimed in claim 2, it is characterized in that: described square wave effective value difference circuit comprises the second operational amplifier, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the second electric capacity and the 3rd electric capacity, the end of oppisite phase of described the second operational amplifier is by the 6th resistance of connecting successively, the 5th resistance is connected with the output terminal of square-wave voltage source exciting circuit, the end of oppisite phase of described the second operational amplifier is by series connection the second capacity earth, in-phase end is by connecting the 7th resistance eutral grounding being connected with output terminal by the 8th resistance, the output terminal of described the second operational amplifier is also connected between the 5th resistance and the 6th resistance by the 3rd electric capacity, the output terminal of described the second operational amplifier is connected with zeroing circuit.
4. a kind of magnetic modulation type current transformer as claimed in claim 3, it is characterized in that: described zeroing circuit comprises the 3rd operational amplifier, the tenth resistance, the 13 resistance, the 6th electric capacity and adjustable resistance, described the 13 resistance and the 6th electric capacity are parallel to respectively between the end of oppisite phase and output terminal of the 3rd operational amplifier, and the end of oppisite phase of described the 3rd operational amplifier is also connected with adjustable resistance, in-phase end connects square wave effective value difference circuit by the tenth resistance output terminal, output terminal are connected with integrating circuit.
5. a kind of magnetic modulation type current transformer as claimed in claim 4, it is characterized in that: described integrating circuit comprises four-operational amplifier, the 14 resistance, the 5th electric capacity and the 8th electric capacity, the end of oppisite phase of described four-operational amplifier is connected with the output terminal of zero-regulator resistor by the 14 resistance, described the 5th electric capacity is connected between the end of oppisite phase and output terminal of four-operational amplifier, the in-phase end ground connection of described four-operational amplifier, output terminal are by the 8th capacity earth, and the output terminal of described four-operational amplifier connects feedback winding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420410337.5U CN204008813U (en) | 2014-07-23 | 2014-07-23 | A kind of magnetic modulation type current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420410337.5U CN204008813U (en) | 2014-07-23 | 2014-07-23 | A kind of magnetic modulation type current transformer |
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| Publication Number | Publication Date |
|---|---|
| CN204008813U true CN204008813U (en) | 2014-12-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420410337.5U Expired - Fee Related CN204008813U (en) | 2014-07-23 | 2014-07-23 | A kind of magnetic modulation type current transformer |
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| CN (1) | CN204008813U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104764919A (en) * | 2015-03-16 | 2015-07-08 | 中国计量学院 | Electronic type voltage transformer based on lossy double integrating circuit |
| CN110456142A (en) * | 2019-08-13 | 2019-11-15 | 上海应用技术大学 | Magnetic modulation type DC leakage flow sensor |
-
2014
- 2014-07-23 CN CN201420410337.5U patent/CN204008813U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104764919A (en) * | 2015-03-16 | 2015-07-08 | 中国计量学院 | Electronic type voltage transformer based on lossy double integrating circuit |
| CN104764919B (en) * | 2015-03-16 | 2017-12-22 | 中国计量学院 | Based on the electronic type voltage transformer for damaging double integrating circuit |
| CN110456142A (en) * | 2019-08-13 | 2019-11-15 | 上海应用技术大学 | Magnetic modulation type DC leakage flow sensor |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141210 Termination date: 20160723 |
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| CF01 | Termination of patent right due to non-payment of annual fee |