CN101900587A - Constant mean value excitation current source of electromagnetic flowmeter - Google Patents
Constant mean value excitation current source of electromagnetic flowmeter Download PDFInfo
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- CN101900587A CN101900587A CN2009100721343A CN200910072134A CN101900587A CN 101900587 A CN101900587 A CN 101900587A CN 2009100721343 A CN2009100721343 A CN 2009100721343A CN 200910072134 A CN200910072134 A CN 200910072134A CN 101900587 A CN101900587 A CN 101900587A
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- 230000005284 excitation Effects 0.000 title claims abstract description 39
- 238000001914 filtration Methods 0.000 claims abstract description 17
- 239000003990 capacitor Substances 0.000 claims description 6
- 230000001131 transforming effect Effects 0.000 claims description 6
- 230000003750 conditioning effect Effects 0.000 abstract description 5
- 238000005070 sampling Methods 0.000 abstract description 5
- 230000009466 transformation Effects 0.000 abstract description 3
- 230000002964 excitative effect Effects 0.000 description 4
- 230000006641 stabilisation Effects 0.000 description 3
- 238000011105 stabilization Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
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Abstract
The invention discloses a constant mean value excitation current source of an electromagnetic flowmeter. With the development of modern industry, higher requirements on performance indexes of the flowmeter are proposed. In the known electromagnetic flowmeter, a flow signal is amplified by generally adopting a peak sampling and holding signal conditioning technology, and a wide-band signal amplifying circuit is used for amplifying various interference noises along with the flow signal, so that the signal-to-noise ratio is low and the resolution is poor. The constant mean value excitation current source comprises a transformation circuit (1), a rectifier filtering circuit (2), a power tube (3), a reference circuit (4), a comparison amplifier (5) and a sampling circuit (6), wherein the transformation circuit (1) is connected with the rectifier filtering circuit (2); and the power tube (3), the reference circuit (4) and the sampling circuit (6) are respectively connected with the comparison amplifier (5). The invention can be used as the excitation current source of the electromagnetic flowmeter.
Description
Technical field:
The present invention relates to a kind of current source, particularly a kind of excitation current source that is used for electromagnetic flowmeter.
Background technology:
Along with development of modern industry, the performance index of flowmeter are had higher requirement.In known electromagnetic flowmeter, peak sampling and holding signal conditioning technology is generally adopted in the amplification of flow signal, its broadband signal amplifying circuit together amplifies multiple interference noise with flow signal, cause signal to noise ratio (S/N ratio) low, differentiate rate variance.
Summary of the invention:
The purpose of this invention is to provide a kind of can be in each cycle of flow signal the constant constant mean value excitation current source of current average, produce and satisfy the required permanent average magnetic field of narrow-band filtering conditioning technology, and then the performance index of raising electromagnetic flowmeter.
For realizing that purpose of the present invention is achieved in that
Constant mean value excitation current source of electromagnetic flowmeter comprises: transforming circuit (1), current rectifying and wave filtering circuit (2), power tube (3), reference circuit (4), comparison amplifier (5) and sample circuit (6), described transforming circuit (1) is connected with current rectifying and wave filtering circuit (2), and described power tube (3), reference circuit (4), sample circuit (6) are connected with comparison amplifier (5) respectively.
Described constant mean value excitation current source of electromagnetic flowmeter, described comparison amplifier (5) is an integrating amplifier, described integrating amplifier is made up of operational amplifier U2, integrating resistor R5 and integrating capacitor C2.
Described constant mean value excitation current source of electromagnetic flowmeter, described power tube (3) is a NPN transistor, have base stage, emitter and collector, described base stage is connected with comparison amplifier (5) output terminal, described collector is connected with current rectifying and wave filtering circuit (2) output terminal, and described emitter is the positive output end of current source.
Described constant mean value excitation current source of electromagnetic flowmeter, described reference circuit (4) comprising: reference source U1, current-limiting resistance R1, divider resistance R2 and divider resistance R3.
Described constant mean value excitation current source of electromagnetic flowmeter, described sample circuit (6) is serially connected on the output current loop.
Beneficial effect:
1, constant mean value excitation current source of electromagnetic flowmeter of the present invention, be according to of the requirement of narrow-band filtering signal condition technology to the excitation power supply in generation magnetic field, make the electric current of output can be in each cycle of flow signal mean value constant, consequent alternating magnetic field keeps mean value constant in each cycle of flow signal, meet narrow-band filtering conditioning Technology Need, improve the performance index of electromagnetic flowmeter.
2, constant mean value excitation current source of electromagnetic flowmeter of the present invention, the magnetizing coil that drives electromagnetic flowmeter produces alternating magnetic field.The working environment of electromagnetic flowmeter is complicated and changeable, and wherein Temperature Influence is particularly evident.Because there is temperature coefficient in the equivalent internal resistance R of magnetizing coil,, thereby influence the stable of alternating magnetic field so temperature variation will directly cause the variation of exciting curent.Adopting permanent average current source technology is that electromagnetic flowmeter is excitatory, can make the temperature stability of alternating magnetic field improve an order of magnitude.
3, constant mean value excitation current source of electromagnetic flowmeter of the present invention, its power supply is from transformation, the rectification of AC network, adopt the permanent average current source shown in the accompanying drawing 2, can effectively suppress the fluctuation that line voltage produces, when line voltage changes in-17%～+ 10% scope, exciting curent mean value in each cycle of flow signal remains stable, and the intensity that produces alternating magnetic field also is permanent all value stabilizations.
4. the desired magnetic field intensity of narrow-band filtering signal condition technology has constant mean value in each cycle of flow signal, this obviously has special requirement to the excitation current source that produces magnetic field, after finding this specific character, we provide a kind of in each cycle of flow signal the constant constant mean value excitation current source of current average.The present invention and excitatory the comparing of constant voltage of generally adopting, permanent average current excitation technology can effectively suppress the influence to the alternating magnetic field of electromagnetic flowmeter of temperature change and voltage ripple of power network.
Permanent excitatory technology of average of electromagnetic flowmeter more of the present invention and the excitatory technology of existing electromagnetic flowmeter, constant mean value excitation current source of the present invention, the electric current of output can be in each cycle of flow signal mean value constant, and then the permanent average alternating magnetic field that the magnetizing coil that drives electromagnetic flowmeter produces keeps constant in each cycle of flow signal, meet narrow-band filtering conditioning Technology Need, can make the temperature stability of the alternating magnetic field of electromagnetic flowmeter improve an order of magnitude, and effectively suppress line voltage and in-17%～+ 10% scope, fluctuate to the influence of permanent average alternating magnetic field, improve the performance index of electromagnetic flowmeter.
Description of drawings:
Accompanying drawing 3 is constant mean value excitation current source of electromagnetic flowmeter working waveform figures of the present invention.
Accompanying drawing 4 is a kind of structural representations of constant mean value excitation current source of electromagnetic flowmeter of the present invention.
Specific embodiments:
With reference to accompanying drawing, be described in detail the preferred specific embodiment of the present invention.
Embodiment 1:
In accompanying drawing 1, constant mean value excitation current source of electromagnetic flowmeter comprises: transforming circuit 1, current rectifying and wave filtering circuit 2, power tube 3, reference circuit 4, comparison amplifier 5 and sample circuit 6.Described transforming circuit 1 is connected with current rectifying and wave filtering circuit 2, and described power tube 3, reference circuit 4, sample circuit 6 are connected with comparison amplifier 5 respectively.
Described constant mean value excitation current source of electromagnetic flowmeter, described power tube is a NPN transistor, has base stage, emitter and collector.Described reference circuit is made up of reference source U1, current-limiting resistance R1, divider resistance R2 and R3.
Described constant mean value excitation current source of electromagnetic flowmeter, described comparison amplifier is an integrating amplifier.Form by operational amplifier U2, integrating resistor R5 and integrating capacitor C2.
Described constant mean value excitation current source of electromagnetic flowmeter, described sample circuit is serially connected in output current loop.
Accompanying drawing 2 provides by the circuit structure in the concrete scheme of constant mean value excitation current source of electromagnetic flowmeter circuit of the present invention.In Fig. 2, show the circuit connecting relation between each components and parts.
In this circuit structure, the positive pole of reference source U1 connects the output terminal of current rectifying and wave filtering circuit through current-limiting resistance R1, the minus earth of reference source U1, the output of reference source U1 is connected with the in-phase input end of R2 dividing potential drop with amplifier U2 through resistance R 1, for permanent average current source provides reference voltage.The inverting input of amplifier U2 is connected with sampling resistor Rn through integrating resistor R5, obtain the comparative voltage of permanent average current source, the output of reference source U1 simultaneously provides the charge or discharge electric current through resistance R 4 to integration capacitor C 2, the other end of integrating capacitor C2 is connected with the output terminal of amplifier U2 and the base stage of power tube Q, the collector of power tube Q connects the output terminal of current rectifying and wave filtering circuit, the positive output end of the very permanent average current source of the emission of power tube Q.
Describe the constant mean value excitation current source course of work of the present invention in detail with reference to accompanying drawing 2:
1) when i (t) is constant, sampled voltage U
0Constant, the A point has I
1=I
2, Ic=0, integrating capacitor C2 do not have the charge or discharge process, and the output voltage of integrating amplifier U2, power tube Q remains unchanged, and circuit is in the current stabilization output state;
2) change I as i (t)
1≠ I
2, Ic (≠ 0) carries out charge or discharge to integration C2, regulates output voltage U through integrating amplifier U2
b, the output voltage Ec of change power tube Q, the current stabilization of realization i (t).
When i (t) increase, have:
If i (t) reduces, then:
Constant mean value excitation current source of the present invention is regulated by taking a sample, relatively realize close-loop feedback, and the electric current of being exported mean value in each cycle of flow signal is constant.
Claims (8)
1. constant mean value excitation current source of electromagnetic flowmeter, comprise: transforming circuit (1), current rectifying and wave filtering circuit (2), power tube (3), reference circuit (4), comparison amplifier (5) and sample circuit (6), it is characterized in that: described transforming circuit (1) is connected with current rectifying and wave filtering circuit (2), and described power tube (3), reference circuit (4), sample circuit (6) are connected with comparison amplifier (5) respectively.
2. constant mean value excitation current source of electromagnetic flowmeter according to claim 1 is characterized in that: described comparison amplifier (5) is an integrating amplifier, and described integrating amplifier is made up of operational amplifier U2, integrating resistor R5 and integrating capacitor C2.
3. constant mean value excitation current source of electromagnetic flowmeter according to claim 1 and 2, it is characterized in that: described power tube (3) is a NPN transistor, have base stage, emitter and collector, described base stage is connected with comparison amplifier (5) output terminal, described collector is connected with current rectifying and wave filtering circuit (2) output terminal, and described emitter is the positive output end of current source.
4. constant mean value excitation current source of electromagnetic flowmeter according to claim 1 and 2 is characterized in that: described reference circuit (4) comprising: reference source U1, current-limiting resistance R1, divider resistance R2 and divider resistance R3.
5. constant mean value excitation current source of electromagnetic flowmeter according to claim 3 is characterized in that: described reference circuit (4) comprising: reference source U1, current-limiting resistance R1, divider resistance R2 and divider resistance R3.
6. according to claim 1 or 2 or 5 described constant mean value excitation current source of electromagnetic flowmeter, it is characterized in that: described sample circuit (6) is serially connected on the output current loop.
7. constant mean value excitation current source of electromagnetic flowmeter according to claim 3 is characterized in that: described sample circuit (6) is serially connected on the output current loop.
8. constant mean value excitation current source of electromagnetic flowmeter according to claim 4 is characterized in that: described sample circuit (6) is serially connected on the output current loop.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100721343A CN101900587B (en) | 2009-05-26 | 2009-05-26 | Constant mean value excitation current source of electromagnetic flowmeter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100721343A CN101900587B (en) | 2009-05-26 | 2009-05-26 | Constant mean value excitation current source of electromagnetic flowmeter |
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| Publication Number | Publication Date |
|---|---|
| CN101900587A true CN101900587A (en) | 2010-12-01 |
| CN101900587B CN101900587B (en) | 2012-08-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009100721343A Expired - Fee Related CN101900587B (en) | 2009-05-26 | 2009-05-26 | Constant mean value excitation current source of electromagnetic flowmeter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104048711A (en) * | 2014-07-04 | 2014-09-17 | 威海市天罡仪表股份有限公司 | Electromagnetic field multi-level strength switching circuit and electromagnetic field multi-level strength switching calculation method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3635878A1 (en) * | 1986-10-22 | 1988-05-05 | Philips Patentverwaltung | Voltage-controlled current source |
| CN2114190U (en) * | 1992-01-09 | 1992-08-26 | 王刚 | Constant-current integrated power supply device |
| CN1036160C (en) * | 1993-12-13 | 1997-10-15 | 朱林盛 | DC regulated power supply of self-generating auxiliary voltage type |
| CN201118449Y (en) * | 2007-11-27 | 2008-09-17 | 中国航天科技集团公司第五研究院第五○二研究所 | Converter with current balance function |
| CN201548272U (en) * | 2009-05-26 | 2010-08-11 | 哈尔滨理工大学 | Current source for electromagnetic flow meter |
-
2009
- 2009-05-26 CN CN2009100721343A patent/CN101900587B/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104048711A (en) * | 2014-07-04 | 2014-09-17 | 威海市天罡仪表股份有限公司 | Electromagnetic field multi-level strength switching circuit and electromagnetic field multi-level strength switching calculation method |
| CN104048711B (en) * | 2014-07-04 | 2017-07-18 | 威海市天罡仪表股份有限公司 | Electromagnetic field multi-level intensity switching circuit and its switching computational methods |
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| CN101900587B (en) | 2012-08-08 |
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Owner name: STATE ELECTRIC NET CROP. Free format text: FORMER OWNER: HARBIN SCIENCE AND ENGINEERING UNIV. Effective date: 20131125 Owner name: MAINTENANCE COMPANY, STATE GRID HEILONGJIANG ELECT Effective date: 20131125 |
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Effective date of registration: 20131125 Address after: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Patentee after: State Grid Corporation of China Patentee after: Maintenance Company of State Grid Heilongjiang Electric Power Company Address before: 150040 No. 52, Xuefu Road, Nangang District, Heilongjiang, Harbin Patentee before: Harbin University of Science and Technology Effective date of registration: 20131125 Address after: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Patentee after: State Grid Corporation of China Patentee after: Maintenance Company of State Grid Heilongjiang Electric Power Company Address before: 150040 No. 52, Xuefu Road, Nangang District, Heilongjiang, Harbin Patentee before: Harbin University of Science and Technology |
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