CN1427264A - Electric current detecting method - Google Patents
Electric current detecting method Download PDFInfo
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- CN1427264A CN1427264A CN 01138877 CN01138877A CN1427264A CN 1427264 A CN1427264 A CN 1427264A CN 01138877 CN01138877 CN 01138877 CN 01138877 A CN01138877 A CN 01138877A CN 1427264 A CN1427264 A CN 1427264A
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- China
- Prior art keywords
- electric current
- point
- sampling resistor
- detecting method
- current detecting
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Abstract
A method for measuring current with different frequencies by a device consisting of detecting unit and amplifier unit features that the three points A, B and C on a conductor are defined, the resistances between A and B and between B and C are used as sampled resistors to serially connected with detecting circuit, the point B is grounded, and the points A and C are connected via resistor to the inputs of operating amplifier package. Its advantages are high input impedance and low output impedance.
Description
Technical field
The present invention belongs to electric current detecting method, specifically a kind ofly gets the method that three point of fixity detect the different frequency electric current.
Background technology
At present, the method that detects electric current in electric system is more, has electromagnetic field couples detection method such as current transformer, Hall element, photo-electricity mutual-inductor to realize indirect detection; But along with improving constantly of electric power transfer capacity, electric current detecting method commonly used just exists the not high shortcoming of heaviness, poor stability, accuracy of detection.
Summary of the invention
The objective of the invention is to develop a kind of method that can directly detect electric current, can realize accuracy of detection height, good stability, easy operating.
This method is to constitute by detecting and amplifying two parts, it is characterized in that the test section is to get A, B, C 3 points on electric conductor, and two segment lengths are respectively L
1And L
2Seal in the detection loop as sampling resistor; The A of sampling resistor, C two ends are respectively through resistance R
1And R
4Two input ends that connect the components for operational amplifier of amplifier section, the B point ground connection of sampling resistor, it is electric conductor (electric wire, conductive bus bar) to be sealed in detect the loop, constitutes sampling resistor (sampling resistor L
1And L
2Sum is of a size of 0.1～8cm), and the electric current of the electric conductor of flowing through produces two small pressure drop Uab and Ubc on three point of fixity of electric conductor.Its two, these two pressure drops are amplified through differential amplifiers, deliver in the one-chip computer after isolating and handle, all kinds of Mechatronic Systems of output control at last.
Bikini among the present invention detects and has the input impedance height, the characteristics that output impedance is low by the circuit that differential amplifier is formed.This method is comparable to but is better than fixedly that two point form directly detects, and more is better than current diverter and detects; The mutual inductor, Hall element and the photo-electric current transformer that are different from electromagnetic field couples detect.
Description of drawings
Accompanying drawing is circuit theory diagrams of the present invention.
Embodiment
Three fixedly the point type sample detecting be based on the Ohm law principle, I=U/R wherein I is the electric current that flows through electric conductor, U be the electric current I that flows through conductor three fixedly ab two point voltages in the point type Uab falls and the Ubc sum falls in bc two point voltages, R is three fixing 2 resistance R ab of ab and Rbc and 2 resistance R bc of bc sums in the point type.
When different electric currents flow through, the sample resistance Rab of electric conductor went up corresponding different respectively voltage drop Uab and Ubc with Rbc; Different electric currents, corresponding different voltage drops, the numerical value that detects voltage drop can draw corresponding current value.
With Uab and Ubc via IC
1, IC
2After the common differential amplifier of forming amplifies, after machine is handled as calculated, can finish various logic control.
Three fixedly common ground and the difference on point type sample detecting and this other detection methods be summarized as follows:
Three fixedly point type sample detecting and two fixedly point type detect and all to be based on the Ohm law principle, both are identical for this point; Different is three fixedly the sample resistance R in the point type be 2 resistance R ab of ab and 2 resistance R bc of bc sum, U is voltage drop Uab and Ubc, the conductor current that different voltage drop Uab and Ubc are corresponding different; Two fixedly the sample resistance R of point type sample detecting be the resistance of ab point-to-point transmission, voltage drop U only is the pressure drop of ab point-to-point transmission, the conductor current that different voltage drop U is corresponding different.
The shunt method detects and also is based on Ohm law, but with two fixedly point type detect and three fixedly the point type detection bigger difference is arranged, though it also is directly to detect on electric conductor that the shunt method detects electric current, the pairing detected object of this method is the branch current that detects electrical conductor.
It all is to adopt partition method that magnetic field manifold type (comprising current transformer, Hall element, photo-electricity mutual-inductor) detects, all there are serious deficiency in volume, energy consumption, sensing range, accuracy of detection, but only with regard to detecting with three point of fixity on its detection method in essence different are arranged.
Claims (2)
1. an electric current detecting method has control section and amplifier section, it is characterized in that the test section is to get A, B, C 3 points on electric conductor, and two segment lengths are respectively L
1And L
2Seal in the detection loop as sampling resistor; The A of sampling resistor, C two ends are respectively through resistance R
1And R
4Two input ends that connect the components for operational amplifier of amplifier section, the B point ground connection of sampling resistor.
2. according to the described electric current detecting method of claim 1, it is characterized in that sampling resistor L
1And L
2Sum is of a size of 0.1～8cm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01138877 CN1427264A (en) | 2001-12-21 | 2001-12-21 | Electric current detecting method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01138877 CN1427264A (en) | 2001-12-21 | 2001-12-21 | Electric current detecting method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1427264A true CN1427264A (en) | 2003-07-02 |
Family
ID=4674829
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01138877 Pending CN1427264A (en) | 2001-12-21 | 2001-12-21 | Electric current detecting method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1427264A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009003395A1 (en) * | 2007-06-29 | 2009-01-08 | Wei Wu | A wide range and high accuracy on-line current and temperature measuring device and method |
| CN101271128B (en) * | 2007-03-23 | 2010-08-25 | 环达电脑(上海)有限公司 | Digital display signal measurement amplifying circuit |
| CN102193018A (en) * | 2010-02-08 | 2011-09-21 | Nxp股份有限公司 | System and method for sensing an amplifier load current |
-
2001
- 2001-12-21 CN CN 01138877 patent/CN1427264A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101271128B (en) * | 2007-03-23 | 2010-08-25 | 环达电脑(上海)有限公司 | Digital display signal measurement amplifying circuit |
| WO2009003395A1 (en) * | 2007-06-29 | 2009-01-08 | Wei Wu | A wide range and high accuracy on-line current and temperature measuring device and method |
| CN102193018A (en) * | 2010-02-08 | 2011-09-21 | Nxp股份有限公司 | System and method for sensing an amplifier load current |
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| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |