CN103149408A - Microcomputer protection device and current sampling circuit thereof - Google Patents
Microcomputer protection device and current sampling circuit thereof Download PDFInfo
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- CN103149408A CN103149408A CN2013100329616A CN201310032961A CN103149408A CN 103149408 A CN103149408 A CN 103149408A CN 2013100329616 A CN2013100329616 A CN 2013100329616A CN 201310032961 A CN201310032961 A CN 201310032961A CN 103149408 A CN103149408 A CN 103149408A
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Abstract
The invention is applied to the relay protection field in an electrical power system, and provides a microcomputer protection device and a current sampling circuit thereof. According to the microcomputer protection device and the current sampling circuit thereof, one set of circuit is adopted to achieve the collection of normal current and fault current of the electrical power system, and can simplify the circuit structure compared with the achieving mode of adoption of two sets of independent circuits. In the current sampling circuit, a first gain control circuit controls gain factors of an integrated operational amplifier circuit when the electrical power system is normal, and a second gain control circuit controls the gain factors of the integrated operational amplifier circuit when current faults happen to the electrical power system. Compared with the existing achieving mode of adoption of one set of circuit, the current sampling circuit improves sampling accuracy of the fault current and the normal current, and further enhances the protection performance of the microcomputer protection device. In addition, the first gain control circuit is in seamless switching with the second gain control circuit, and the switching can be achieved without the need of a switch, so the sampling speed is high, and the protection performance of the microcomputer protection device is further enhanced.
Description
Technical field
The invention belongs to the relay protection field of electric system, relate in particular to microcomputer protecting device and current sampling circuit thereof in a kind of electric system.
Background technology
Microcomputer protecting device is a kind of being applied in electric system, in order to the measurement that realizes electric current and voltage and the device of protection.Microcomputer protecting device utilizes the variation of operational factor in the Operation of Electric Systems process (as: electric current, voltage, power-factor angle etc.); judge nature of trouble and the scope of electric system, in order to and then make respective reaction and processing (as: send warning signal or make circuit breaker trip etc.).Therefore, in microcomputer protecting device, particularly important in order to the performance of the data acquisition system (DAS) that gathers operational factor, the speed of its collection, precision and dynamic range have very important impact to the protective value of microcomputer protecting device.
When breaking down, fault current if will realize protecting accurately and reliably, must all carry out quick, high-precision sampling than large several times of normal current, even tens times to normal current and fault current due to electric system.In prior art, in the data acquisition system (DAS) of microcomputer protecting device, the current sampling circuit that is used for the collection fault current has following two kinds of implementations: one, adopt circuit kit, it is simple in structure, but dynamic range is little, sampling precision to normal current is low, can't satisfy required sampling precision, makes the protective value of microcomputer protecting device poor; Two, adopt two to overlap independently circuit; when being used for working in system, circuit kit wherein gathers normal current; the another set of fault current that gathers when breaking down in system; this circuit complexity that realizes; cost is high, and two switchings of cover between circuit control by switch, can have a switching process in handoff procedure; cause sample rate slow, and then reduced the protective value of microcomputer protecting device.
Summary of the invention
The object of the present invention is to provide a kind of current sampling circuit of microcomputer protecting device; be intended to solve in existing microcomputer protecting device; perhaps sampling precision is low owing to adopting circuit kit; perhaps owing to adopting two to overlap independent circuits and complex structure; and sample rate is slow, causes the problem of protected by microcomputer protecting equipment poor performance.
The present invention is achieved in that a kind of current sampling circuit of microcomputer protecting device, and described current sampling circuit comprises:
Alternating current sampling circuit is used for converting the ac current signal of electric system to first voltage signal;
Integrated operational amplifier circuit is used for described the first voltage signal is carried out gain-adjusted, and output second voltage signal;
Output circuit is used for described second voltage signal is converted to and can identifies voltage signal and output;
The first gain control circuit is used for controlling the gain coefficient of described integrated operational amplifier circuit when described electric system normal operation;
The second gain control circuit is used for controlling the gain coefficient of described integrated operational amplifier circuit when described electric power system fault.
Another object of the present invention is to, a kind of microcomputer protecting device also is provided, described device comprises the current sampling circuit of microcomputer protecting device as above.
Microcomputer protecting device provided by the invention and current sampling circuit thereof adopt circuit kit to realize the collection of electric system normal current and fault current, with respect to the existing implementation that adopts two cover independent circuits, can simplify circuit structure; In this circuit, the first gain control circuit is controlled the gain coefficient of integrated operational amplifier circuit when electric system is normal, the second gain control circuit is controlled the gain coefficient of integrated operational amplifier circuit when current failure appears in electric system, with respect to the existing implementation that adopts circuit kit, improve the sampling precision of fault current and normal current, and then strengthened the protective value of microcomputer protecting device; In addition, be seamless switching between the first gain control circuit and the second gain control circuit, and need not realize switching by switch; with respect to the existing implementation that adopts two cover independent circuits; circuit is simple, and sample rate is fast, has further strengthened the protective value of microcomputer protecting device.
Description of drawings
Fig. 1 is the circuit theory diagrams of the current sampling circuit of microcomputer protecting device provided by the invention;
Fig. 2 is the circuit diagram of Fig. 1.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, is not intended to limit the present invention.
For the problem that prior art exists, the invention provides the current sampling circuit of a cover microcomputer protecting device, in this circuit, the first gain control circuit is worked when electric system is normal, and the second gain control circuit is worked when current failure appears in electric system.
Fig. 1 shows the circuit theory of the current sampling circuit of microcomputer protecting device provided by the invention, for convenience of explanation, only shows part related to the present invention.
The current sampling circuit of microcomputer protecting device provided by the invention comprises: alternating current sampling circuit 11 is used for converting the ac current signal of electric system to first voltage signal; Integrated operational amplifier circuit 12 is used for the first voltage signal is carried out gain-adjusted, and output second voltage signal; Output circuit 13 is used for the second voltage signal is converted to and can identifies voltage signal and output; The first gain control circuit 14 is used for when electric system works the gain coefficient of control integration discharge circuit 12; The second gain control circuit 15 is used for when electric power system fault the gain coefficient of control integration discharge circuit 12.
The current sampling circuit of microcomputer protecting device provided by the invention adopts circuit kit to realize the collection of electric system normal current and fault current, with respect to the existing implementation that adopts two cover independent circuits, can simplify circuit structure; In this circuit, the first gain control circuit is controlled the gain coefficient of integrated operational amplifier circuit when electric system is normal, the second gain control circuit is controlled the gain coefficient of integrated operational amplifier circuit when current failure appears in electric system, with respect to the existing implementation that adopts circuit kit, improve the sampling precision of fault current and normal current, and then strengthened the protective value of microcomputer protecting device; In addition; be seamless switching between the first gain control circuit and the second gain control circuit, and need not realize switching by switch, with respect to the existing implementation that adopts two cover independent circuits; sample rate is fast, has further strengthened the protective value of microcomputer protecting device.
Fig. 2 shows the circuit of Fig. 1.
Particularly, alternating current sampling circuit 11 can comprise: current transformer T, the two ends of its winding connect the transmission line of electricity of electric system, one end of its Secondary Winding connects equipotential, and the other end of its Secondary Winding connects integrated operational amplifier circuit 12, the first gain control circuit 14 and the second gain control circuit 15 as the output terminal of alternating current sampling circuit 11.
In the present invention, utilize winding and the Secondary Winding of current transformer T, can realize effective isolation of high-pressure side and low-pressure side, and convert the ac current signal of primary side input to the first voltage signal that secondary side is exported, the ac current signal of the 0 ~ 100A that for example, primary side can be inputted converts the first voltage signal of 0 ~ 3.53V of secondary side output to.
Particularly, integrated operational amplifier circuit 12 can comprise: operational amplifier A, resistance R 3, resistance R 4.Wherein, the inverting input of operational amplifier A connects the output terminal of alternating current sampling circuit 11 by resistance R 3, the in-phase input end of operational amplifier A connects equipotential by resistance R 4, the output terminal of operational amplifier A connects between the output terminal that output circuit 13, the first gain control circuits 14 and the second gain control circuit 15 be connected in parallel on respectively the output terminal of alternating current sampling circuit 11 and operational amplifier A as the output terminal of integrated operational amplifier circuit 12.
Further, the impact of the high pressure of introducing for fear of current transformer T chance failure on circuit devcie, integrated operational amplifier circuit 12 also can comprise a holding circuit.This holding circuit specifically comprises: be arranged on the output terminal of alternating current sampling circuit 11, and diode D1 and diode D2 between integrated operational amplifier circuit 12, the first gain control circuit 14 and the second gain control circuit 15; Wherein the negative electrode of diode D1 is connected anode and is connected respectively the output terminal of alternating current sampling circuit 11 with diode D2, and the anode of diode D1 is connected negative electrode and is connected respectively equipotential with diode D2.
Particularly, output circuit 13 can comprise: capacitor C 2, and the one end connects the output terminal of integrated operational amplifier circuit 12, and its other end can be identified voltage signal as the output terminal of the current sampling circuit of microcomputer protecting device in order to output.Be input in the digital processing chips such as singlechip chip or dsp chip, further to carry out mould/number conversion to identifying voltage signal after the voltage signal identified of capacitor C 2 other end outputs.
Particularly, the first gain control circuit 14 can comprise: resistance R 2 and capacitor C 1.Resistance R 2 and capacitor C 1 are connected in parallel on respectively between the output terminal of the output terminal of alternating current sampling circuit 11 and operational amplifier A.
Particularly, the second gain control circuit 15 can comprise: stabilivolt D3, stabilivolt D4 and resistance R 1.Wherein, stabilivolt D3, stabilivolt D4 and resistance R 1 are connected between the output terminal of the output terminal of alternating current sampling circuit 11 and operational amplifier A, and the output terminal of the anodic bonding alternating current sampling circuit 11 of stabilivolt D3, the negative electrode of stabilivolt D3 connects the negative electrode of stabilivolt D4.
Circuit shown in Figure 2 is when work, and current transformer T converts ac current signal to first voltage signal.Afterwards, if the electric system normal operation, the voltage between the output terminal of alternating current sampling circuit 11 and the output terminal of operational amplifier A does not reach the first predeterminated voltage value, and resistance R 2 place branch road work are to realize the sampling of current signal in the small-range scope; If electric system is broken down, make the voltage between the output terminal of the output terminal of alternating current sampling circuit 11 and operational amplifier A reach the first predeterminated voltage value, stabilivolt D3, stabilivolt D4 and resistance R 1 place branch road work, pressure stabilization function with signal that moment is increased suddenly by stabilivolt D3 and stabilivolt D4 carries out effective attenuation, avoid signal excessive and cause outrange, caused follow-up digital processing chip None-identified.The first predeterminated voltage value wherein is 6.2V preferably.
The present invention also provides a kind of microcomputer protecting device, comprises the current sampling circuit of microcomputer protecting device as above.
Microcomputer protecting device provided by the invention and current sampling circuit thereof adopt circuit kit to realize the collection of electric system normal current and fault current, with respect to the existing implementation that adopts two cover independent circuits, can simplify circuit structure; In this circuit, the first gain control circuit is controlled the gain coefficient of integrated operational amplifier circuit when electric system is normal, the second gain control circuit is controlled the gain coefficient of integrated operational amplifier circuit when current failure appears in electric system, with respect to the existing implementation that adopts circuit kit, improve the sampling precision of fault current and normal current, and then strengthened the protective value of microcomputer protecting device; In addition; be seamless switching between the first gain control circuit and the second gain control circuit, and need not realize switching by switch, with respect to the existing implementation that adopts two cover independent circuits; sample rate is fast, has further strengthened the protective value of microcomputer protecting device.
The above is only preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, is equal to and replaces and improvement etc., within all should being included in protection scope of the present invention.
Claims (10)
1. the current sampling circuit of a microcomputer protecting device, is characterized in that, described current sampling circuit comprises:
Alternating current sampling circuit is used for converting the ac current signal of electric system to first voltage signal;
Integrated operational amplifier circuit is used for described the first voltage signal is carried out gain-adjusted, and output second voltage signal;
Output circuit is used for described second voltage signal is converted to and can identifies voltage signal and output;
The first gain control circuit is used for controlling the gain coefficient of described integrated operational amplifier circuit when described electric system normal operation;
The second gain control circuit is used for controlling the gain coefficient of described integrated operational amplifier circuit when described electric power system fault.
2. the current sampling circuit of microcomputer protecting device as claimed in claim 1, is characterized in that, described integrated operational amplifier circuit comprises operational amplifier, resistance R 3, resistance R 4;
The inverting input of described operational amplifier connects the output terminal of described alternating current sampling circuit by described resistance R 3, the in-phase input end of described operational amplifier connects equipotential by described resistance R 4, the output terminal of described operational amplifier connects described output circuit as the output terminal of described integrated operational amplifier circuit, and described the first gain control circuit and described the second sub gain control circuit are not connected in parallel between the output terminal of the output terminal of described alternating current sampling circuit and described operational amplifier.
3. the current sampling circuit of microcomputer protecting device as claimed in claim 2, is characterized in that, described the first gain control circuit comprises resistance R 2 and capacitor C 1;
Described resistance R 2 and described capacitor C 1 are connected in parallel on respectively between the output terminal of the output terminal of described alternating current sampling circuit and described operational amplifier.
4. the current sampling circuit of microcomputer protecting device as claimed in claim 3; it is characterized in that; when the voltage between the output terminal of the output terminal of described alternating current sampling circuit and described operational amplifier does not reach the first predeterminated voltage value, described resistance R 2 place parallel branches work.
5. the current sampling circuit of microcomputer protecting device as claimed in claim 2, is characterized in that, described the second gain control circuit comprises: stabilivolt D3, stabilivolt D4 and resistance R 1;
Described stabilivolt D3, described stabilivolt D4 and described resistance R 1 are connected between the output terminal of the output terminal of described alternating current sampling circuit and described operational amplifier, and the output terminal of the described alternating current sampling circuit of anodic bonding of described stabilivolt D3, the negative electrode of described stabilivolt D3 connects the negative electrode of described stabilivolt D4.
6. the current sampling circuit of microcomputer protecting device as claimed in claim 5; it is characterized in that; when the voltage between the output terminal of the output terminal of described alternating current sampling circuit and described operational amplifier reaches the first predeterminated voltage value, described the second gain control circuit work.
7. the current sampling circuit of microcomputer protecting device as claimed in claim 2, it is characterized in that, described integrated operational amplifier circuit also comprises: be arranged on the output terminal of described alternating current sampling circuit, and diode D1 and diode D2 between described integrated operational amplifier circuit, described the first gain control circuit and described the second gain control circuit;
The negative electrode of described diode D1 be connected the anode of diode D2 and connect respectively the output terminal of described alternating current sampling circuit, the anode of described diode D1 be connected the negative electrode of diode D2 and connect respectively equipotential.
8. the current sampling circuit of microcomputer protecting device as claimed in claim 1, is characterized in that, described alternating current sampling circuit comprises:
Current transformer T, the two ends of the winding of described current transformer T connect the transmission line of electricity of described electric system, one end of the Secondary Winding of described current transformer T connects equipotential, and the other end of the Secondary Winding of described current transformer T connects described integrated operational amplifier circuit, described the first gain control circuit and described the second gain control circuit as the output terminal of described alternating current sampling circuit.
9. the current sampling circuit of microcomputer protecting device as claimed in claim 1, is characterized in that, described output circuit comprises:
Capacitor C 2, an end of described capacitor C 2 connects the output terminal of described integrated operational amplifier circuit, and the other end of described capacitor C 2 is as the output terminal of described current sampling circuit, in order to export the described voltage signal of identifying.
10. a microcomputer protecting device, is characterized in that, described device comprises the current sampling circuit as the described microcomputer protecting device of claim 1 to 9 any one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310032961.6A CN103149408B (en) | 2013-01-29 | 2013-01-29 | Microcomputer protection device and current sampling circuit thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310032961.6A CN103149408B (en) | 2013-01-29 | 2013-01-29 | Microcomputer protection device and current sampling circuit thereof |
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| CN103149408A true CN103149408A (en) | 2013-06-12 |
| CN103149408B CN103149408B (en) | 2015-07-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201310032961.6A Expired - Fee Related CN103149408B (en) | 2013-01-29 | 2013-01-29 | Microcomputer protection device and current sampling circuit thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104777340A (en) * | 2014-12-31 | 2015-07-15 | 陈瑞武 | Circuit for testing standby current |
| CN108226620A (en) * | 2016-12-22 | 2018-06-29 | 航天信息股份有限公司 | A kind of voltage sensor signal conditioning circuit |
| CN112630515A (en) * | 2020-12-01 | 2021-04-09 | 苏州臻迪智能科技有限公司 | Current sampling method, device and system and unmanned aerial vehicle |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104777340A (en) * | 2014-12-31 | 2015-07-15 | 陈瑞武 | Circuit for testing standby current |
| CN108226620A (en) * | 2016-12-22 | 2018-06-29 | 航天信息股份有限公司 | A kind of voltage sensor signal conditioning circuit |
| CN112630515A (en) * | 2020-12-01 | 2021-04-09 | 苏州臻迪智能科技有限公司 | Current sampling method, device and system and unmanned aerial vehicle |
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| Publication number | Publication date |
|---|---|
| CN103149408B (en) | 2015-07-01 |
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Granted publication date: 20150701 Termination date: 20210129 |