CN103151993A - Precision alternating current amplifier - Google Patents

Precision alternating current amplifier Download PDF

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Publication number
CN103151993A
CN103151993A CN2013100352364A CN201310035236A CN103151993A CN 103151993 A CN103151993 A CN 103151993A CN 2013100352364 A CN2013100352364 A CN 2013100352364A CN 201310035236 A CN201310035236 A CN 201310035236A CN 103151993 A CN103151993 A CN 103151993A
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China
Prior art keywords
current
transformer
circuit
operational amplifier
input
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CN2013100352364A
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Chinese (zh)
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CN103151993B (en
Inventor
付济良
王旭
王斯琪
周玮
匡义
徐晨
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State Grid Corp of China SGCC
China Electric Power Research Institute Co Ltd CEPRI
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China Electric Power Research Institute Co Ltd CEPRI
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Abstract

The invention relates to a precision alternating current amplifier, which can be used for amplifying an alternating current standard current source in an equal proportion at high accuracy in real time and has good amplitude gain stability and phase stability. The precision alternating current amplifier comprises an input and output port, a current amplifying circuit, a direct current clamping circuit and a high frequency filter circuit, wherein the current amplifying circuit is an alternating current negative feedback loop consisting of an operational amplifier, a transformer and a current transformer; and in a working frequency range, high-accuracy amplification of the alternating current standard current source is realized. The direct current clamping circuit consists of an integrating circuit and a low-pass filter circuit and is used for eliminating non-linear influence of the transformer and the current transformer in case of direct current. The high-frequency filter circuit is used for preventing the current amplifying circuit from oscillating. The precision alternating current amplifier has the advantages of low cost, real-time response, high accuracy, current output loop isolation, high power utilization rate and the like.

Description

Accurate alternating current amplifier
Technical field
The present invention relates to a kind of accurate alternating current amplifier, belong to calibration, calibrating and detection field to the power test instrument, particularly a kind ofly can carry out the device that high accuracy is amplified to exchanging the normalized current source.
Background technology
In calibration, calibrating and testing to power test instrument with Super-Current Measurement ability, the large electric current that often needs to provide output current to reach tens amperes exchanges the normalized current source.Little electric current exchanges the standard source ratio and is easier to obtain, and large electric current low-cost, high accuracy exchanges difficult acquisition the in normalized current source.
Large electric current interchange normalized current source generally exchanges standard source by little electric current and realizes through the alternating current amplifier.For making output current reach tens amperes, traditional alternating current amplifier mainly contains following several mode.
Programmable amplifier, transformer, microprocessor compound mode: signal is through preposition program control amplification, and transformer expands stream, by current sample, regulates the programmable amplifier gain after microprocessor calculates, and makes outputting current steadily in set point.This mode signal source and amplifier one need microprocessor to coordinate, and be high to each circuit element stability requirement, complex structure, and underaction, and the output current adjusting has hysteresis quality.
Operational amplifier, power tube compound mode: this mode needs fan-out capability to reach large current power pipe and the power supply of tens amperes, and power consumption is large, and the zero crossing intermodulation distortion is difficult for overcoming.
Great current operation amplifier type of drive: this mode needs fan-out capability to reach great current operation amplifier and the power supply of tens amperes, and cost is high, and power consumption is large.
Precision current transformer expands the stream mode: the required precision current transformer structure of this mode is heavy, and cost is high, and a little less than carrying load ability.
In view of this, be necessary to provide a kind of accurate alternating current amplifier, can exchange standard source to little electric current and carry out the real-time equal proportion amplification of high accuracy, to satisfy the commercial Application needs.
Summary of the invention
Technical problem to be solved by this invention is: for the deficiency of existing alternating current amplifying technique, a kind of improved accurate alternating current amplifier is provided, can exchange the normalized current source to small-signal carries out the real-time equal proportion of high accuracy and amplifies, have good amplitude gain stability and phase stability, thereby provide condition and guarantee for the high accuracy verifying work of the power test quasi-instrument that possesses the Super-Current Measurement ability.
The technical solution adopted in the present invention is: a kind of accurate alternating current amplifier, consisted of by input/output port, current amplification circuit, direct current clamp circuit, high-frequency filter circuit, and it is characterized in that:
Described current amplification circuit comprises the first operational amplifier, transformer, current transformer; The first operational amplifier U1 reverse input end connects the current input terminal mouth, and its output connects the transformer input; Transformer output series current instrument transformer connects the current output terminal mouth; Current transformer output connects the first operational amplifier reverse input end;
Described direct current clamp circuit comprises the second operational amplifier, resistance, electric capacity; The second operational amplifier U2 and resistance R 1, capacitor C 2 form integrating circuit; Resistance R 2, R3 and capacitor C 3 form low-pass filter circuit; The integrating circuit input connects the first operational amplifier output terminal of current amplification circuit, and output connects the low-pass filter circuit input; Low-pass filter circuit output connects the first operational amplifier positive input of current amplification circuit;
Described high-frequency filter circuit comprises capacitor C 1; The first operational amplifier output terminal of capacitor C 1 one termination current amplification circuits, the first operational amplifier inverting input of another termination current amplification circuit.
Accurate alternating current amplifier as above is characterized in that the first operational amplifier of described current amplification circuit is the great current operation amplifier; Transformer is rising current transformer; Current transformer is the accurate AC current transformer of instrument.
Accurate alternating current amplifier as above is characterized in that, the precision resistance of can also connecting between described current amplification circuit input and signal source, make exchange standard voltage source also can be as the input standard source.
The invention has the beneficial effects as follows: except the rising current transformer output loop was large electric current, other subelements of circuit comprised that power supply all is operated in low current condition, and power utilization is high, and cost is low; Output current is with the input current signal real-time change, and mainly by the precision current transformer decision, accuracy is high for output current wave and phase place.Other element electrical isolation in electric current output loop and circuit, effectively the protective circuit element, do not exist again and load problem altogether.
Description of drawings
Fig. 1 is the circuit theory schematic diagram of the accurate alternating current amplifier of the present invention.
Embodiment
In order to understand better the present invention, further illustrate content of the present invention below in conjunction with embodiment, but content of the present invention not only is confined to the following examples.Those skilled in the art can make various changes or modifications the present invention, and these equivalent form of values are equally within the listed claims limited range of the application.
The explanation of each number in the figure: A, B-input port, C, D-output port, U1-current amplification circuit operational amplifier, U2-integrating circuit operational amplifier, T1-rising current transformer, T2-current transformer, R1-integrating circuit resistance, R2, R3-low-pass filter circuit resistance, C1-high-frequency filter capacitor, C2-integrating capacitor, C3-low-pass filter circuit electric capacity, GND-ground reference point.
The invention provides a kind of accurate alternating current amplifier, can carry out the real-time equal proportion of high accuracy to interchange normalized current source and amplify, have good amplitude gain stability and phase stability.It comprises input/output port, current amplification circuit, direct current clamp circuit, high-frequency filter circuit.Current amplification circuit consists of the alternating current negative feedback loop by operational amplifier, transformer summation current transformer, in working frequency range, realizes exchanging the high accuracy amplification in normalized current source.The direct current clamp circuit is comprised of integrating circuit and low-pass filter circuit, is used for the non-linear effects of eliminating transformer summation current transformer when direct current.High-frequency filter circuit is used for preventing the current amplification circuit vibration.
As shown in Figure 1, a kind of accurate alternating current amplifier is made of input/output port, current amplification circuit, direct current clamp circuit, high-frequency filter circuit, it is characterized in that:
Described current amplification circuit relates to operational amplifier U1, transformer, current transformer; Operational amplifier U1 reverse input end connects the current input terminal mouth, and its output connects the transformer input; Transformer output series current instrument transformer connects the current output terminal mouth; Current transformer output connects operational amplifier U1 reverse input end;
Described direct current clamp circuit relates to operational amplifier U2, resistance, electric capacity; Operational amplifier U2 and resistance R 1, capacitor C 2 form integrating circuit; Resistance R 2, R3 and capacitor C 3 form low-pass filter circuit; The integrating circuit input connects current amplification circuit operational amplifier U1 output, and output connects the low-pass filter circuit input; Low-pass filter circuit output connects current amplification circuit operational amplifier U1 positive input;
Described high-frequency filter circuit relates to electric capacity; Electric capacity one termination current amplification circuit operational amplifier U1 output, another termination current amplification circuit operational amplifier U1 inverting input.
Accurate alternating current amplifier as above is characterized in that the operational amplifier of described current amplification circuit is the great current operation amplifier; Transformer is rising current transformer; Current transformer is the accurate AC current transformer of instrument.
Accurate alternating current amplifier as above is characterized in that, the precision resistance of also can connecting between described current amplification circuit input and signal source can exchange small-signal standard voltage source and convert large electric current to and exchange the normalized current source.
Operation principle of the present invention is: operational amplifier U1, transformer T1 summation current transformer T2 form the alternating current negative-feedback circuit.In the alternate current operation frequency range: operational amplifier output current ability is Im, and transformer T1 output is N with input current ratio, and the amplifier current fan-out capability is N*Im; Current transformer output is K with input current ratio, and the relational expression of amplifier output current Io and input current Ii is: Io=Ii/K.
Because transformer T1, current transformer T2 are non-linear element, direct current signal can't pass through, and high-frequency signal can produce high additional phase shift, thereby need to increase DC feedback and high frequency feedback loop, to ensure the amplifier circuit normal operation.Increase direct current clamp circuit and high-frequency filter circuit for this reason.The direct current clamp circuit is comprised of integrating circuit and low-pass filter circuit, makes operational amplifier U1 output DC level clamper in ground potential points, and in working frequency range, AC signal is influenced hardly.High-frequency filter circuit makes high fdrequency component directly feed back to operational amplifier U1 reverse input end by capacitor C 1, to avoid the amplifier circuit vibration.
The content that is not described in detail in this specification belongs to the known prior art of this area professional and technical personnel.

Claims (3)

1. an accurate alternating current amplifier, be made of input/output port, current amplification circuit, direct current clamp circuit, high-frequency filter circuit, it is characterized in that:
Described current amplification circuit comprises the first operational amplifier, transformer, current transformer; The first operational amplifier U1 reverse input end connects the current input terminal mouth, and its output connects the transformer input; Transformer output series current instrument transformer connects the current output terminal mouth; Current transformer output connects the first operational amplifier reverse input end;
Described direct current clamp circuit comprises the second operational amplifier, resistance, electric capacity; The second operational amplifier U2 and resistance R 1, capacitor C 2 form integrating circuit; Resistance R 2, R3 and capacitor C 3 form low-pass filter circuit; The integrating circuit input connects the first operational amplifier output terminal of current amplification circuit, and output connects the low-pass filter circuit input; Low-pass filter circuit output connects the first operational amplifier positive input of current amplification circuit;
Described high-frequency filter circuit comprises capacitor C 1; The first operational amplifier output terminal of capacitor C 1 one termination current amplification circuits, the first operational amplifier inverting input of another termination current amplification circuit.
2. accurate alternating current amplifier according to claim 1, is characterized in that, the first operational amplifier of described current amplification circuit is the great current operation amplifier; Transformer is rising current transformer; Current transformer is the accurate AC current transformer of instrument.
3. accurate alternating current amplifier according to claim 1, is characterized in that, the precision resistance of can also connecting between described current amplification circuit input and signal source, make exchange standard voltage source also can be as the input standard source.
CN201310035236.4A 2013-01-30 2013-01-30 Accurate alternating current amplifier Active CN103151993B (en)

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CN103151993B CN103151993B (en) 2017-06-16

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104410374A (en) * 2014-09-29 2015-03-11 国家电网公司 Precise alternating voltage amplifier
CN105278599A (en) * 2015-10-22 2016-01-27 国家电网公司 Voltage-controlled current source circuit using CT to replace current sensing resistor
CN106353558A (en) * 2016-08-26 2017-01-25 成都鑫豪斯电子探测技术有限公司 The co-signal processor of inductive load and resistive load used for electrical fire supervision
CN107017850A (en) * 2016-01-28 2017-08-04 江苏省电力公司南京供电公司 A kind of voltage power amplifying circuit
CN107017851A (en) * 2016-01-28 2017-08-04 江苏省电力公司南京供电公司 A kind of current power amplifying circuit
CN107192973A (en) * 2017-05-27 2017-09-22 中国电力科学研究院 Leakage current of an arrester compensation system and method under a kind of electric field environment

Citations (4)

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Publication number Priority date Publication date Assignee Title
US5696441A (en) * 1994-05-13 1997-12-09 Distribution Control Systems, Inc. Linear alternating current interface for electronic meters
CN102185555A (en) * 2010-12-28 2011-09-14 上海智大电子有限公司 Digitalized alternating-current voltage and speed regulation device
CN102841227A (en) * 2012-08-15 2012-12-26 广东电网公司电力科学研究院 High precision large alternating current output device
CN203193573U (en) * 2013-01-30 2013-09-11 中国电力科学研究院 Precise alternating current amplifier

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5696441A (en) * 1994-05-13 1997-12-09 Distribution Control Systems, Inc. Linear alternating current interface for electronic meters
CN102185555A (en) * 2010-12-28 2011-09-14 上海智大电子有限公司 Digitalized alternating-current voltage and speed regulation device
CN102841227A (en) * 2012-08-15 2012-12-26 广东电网公司电力科学研究院 High precision large alternating current output device
CN203193573U (en) * 2013-01-30 2013-09-11 中国电力科学研究院 Precise alternating current amplifier

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李鹤等: "直流输电用零磁通直流电流互感其的研制", 《高压电技术》 *
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104410374A (en) * 2014-09-29 2015-03-11 国家电网公司 Precise alternating voltage amplifier
CN105278599A (en) * 2015-10-22 2016-01-27 国家电网公司 Voltage-controlled current source circuit using CT to replace current sensing resistor
CN107017850A (en) * 2016-01-28 2017-08-04 江苏省电力公司南京供电公司 A kind of voltage power amplifying circuit
CN107017851A (en) * 2016-01-28 2017-08-04 江苏省电力公司南京供电公司 A kind of current power amplifying circuit
CN106353558A (en) * 2016-08-26 2017-01-25 成都鑫豪斯电子探测技术有限公司 The co-signal processor of inductive load and resistive load used for electrical fire supervision
CN107192973A (en) * 2017-05-27 2017-09-22 中国电力科学研究院 Leakage current of an arrester compensation system and method under a kind of electric field environment

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