CN1267832A - Analogue signal processor for magneto-optical current transformer - Google Patents
Analogue signal processor for magneto-optical current transformer Download PDFInfo
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- CN1267832A CN1267832A CN 00105931 CN00105931A CN1267832A CN 1267832 A CN1267832 A CN 1267832A CN 00105931 CN00105931 CN 00105931 CN 00105931 A CN00105931 A CN 00105931A CN 1267832 A CN1267832 A CN 1267832A
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Abstract
本发明涉及一种用于磁光式电流互感器的模拟信号处理器,包括接受由光电探测器输出的电信号,并将其放大的前置放大器,用于对来自前置放大器的交流信号再次放大、滤波、移相,从而得到交流信号的交流通道,用于将来自前置放大器的信号进行小于1Hz的低通滤波,再放大,以产生所需的直流电压信号的直流通道,用于将交流与直流电压信号进行除法运算的除法电路。本发明可以抑制温度、双折射及其他噪声和干扰对磁光式电流互感器的影响。
The invention relates to an analog signal processor for a magneto-optical current transformer, which includes a preamplifier that receives and amplifies the electrical signal output by a photodetector, and is used to re-amplify the AC signal from the preamplifier Amplify, filter, and phase-shift to obtain the AC channel of the AC signal, which is used to low-pass filter the signal from the preamplifier less than 1 Hz, and then amplify to generate the required DC voltage signal. The DC channel is used to convert the A division circuit for dividing AC and DC voltage signals. The invention can suppress the influence of temperature, birefringence and other noises and disturbances on the magneto-optical current transformer.
Description
The present invention relates to a kind of analogue signal processor that is used for magneto-optical current transformer, belong to electric system metrological testing technology field.
The various optical current mutual inductors that proposed at present adopt Faraday magnetooptical effect to measure more, claim that thus such mutual inductor is a magneto-optical current transformer.The essence of magneto-optic effect is that optical material produces a kind of nonlinear polarization process under externally-applied magnetic field and the acting in conjunction of light wave electric field.When a branch of linearly polarized light when placing the magneto-optic memory technique in magnetic field, the linear polarization polarization surface will be linearly along with the magnetic field size that is parallel to radiation direction rotates; By measuring the variation of through-flow conductor circumferential wire polarized light plane of polarization, just can measure the current value in the conductor indirectly.
Generally form by the magneto-optical current transformer that block magneto-optic glass is realized: light source, the polarizer, optical glass sensing head, analyzer, photodetector, signal processing unit etc. by following device and unit.Above device itself and their combination are all relevant with external environment influences such as temperature, stress.The material of optical pickup is generally selected optical glass for use, will produce different optical effects under outer field action, as electrooptical effect, elasto-optical effect, acoustooptic effect, thermo-optic effect, photorefractive effect or the like.Together with top magneto-optic effect, they all are the functions of temperature.Therefore the optical effect that takes place in magneto-optical current transformer is actually the comprehensive result of various effects, and wherein the influence of temperature and stress aspect is the most serious, and makes the development of magneto-optical current transformer run into unprecedented difficulty.
Magneto-optical current transformer studied for two more than ten years, on principle, be mature on the whole, but also there are some problems in commodity practicability aspect, as mentioned above, temperature, birefringence are the principal elements that influences the magneto-optical current transformer measuring accuracy, although people adopt: the polarizer and analyzer have the fixed orientation angle, directed 10.45 ° of the polarizer and optical axis, directed 55.45 ° of analyzer; Output signal AC compounent and DC component are divided by; Biorthogonal total reflection geometric phase penalty method compensation total reflection differs; Accurately reflect methods such as critical angle, but still fundamentally do not solve the influence of temperature and stress magneto-optical current transformer.This patent produces under this background just, and it utilizes the semiconductor absorption temperature sensor that the sensing head of magneto-optical current transformer is carried out the temperature direct compensation, in order to eliminate the influence of temperature variation to mutual inductor; The light source drive current adopts constant current control simultaneously, reduces the influence of light intensity variation to magneto-optical current transformer.At last, these signal processing circuits and other element manufacturing on a cell board, have been formed one and have been used for the analogue signal processor that magneto-optical current transformer has temperature compensation function.
The objective of the invention is to propose a kind of analogue signal processor that is used for magneto-optical current transformer, to suppress temperature, birefringence and other noises and interference influence effectively to magneto-optical current transformer.Utilize the semiconductor absorption temperature sensor that the sensing head of magneto-optical current transformer is carried out the temperature direct compensation, in order to eliminate the influence of temperature variation to mutual inductor; Adopt constant current control with the light source drive current simultaneously, reduce the influence of light intensity variation magneto-optical current transformer.
The analogue signal processor that is used for magneto-optical current transformer that the present invention proposes comprises prime amplifier, communication channel, direct current channel, division circuit, temperature compensation feedback circuit, light source constant-current drive circuit.Wherein, described prime amplifier is accepted the electric signal by photodetector output, and with its amplification, and it comprises photodetector, proportional amplifier, resistance and electric capacity.Described communication channel is used for AC signal amplification once more, filtering, phase shift from prime amplifier, thereby obtains the AC signal of 10Hz～2kHz, comprising: AD624 amplifier, low-pass filter, Hi-pass filter, phase shifter.Described direct current channel is used for the signal from prime amplifier is carried out low-pass filtering less than 1Hz, amplifies again, and to produce required d. c. voltage signal, it comprises a passive low ventilating filter and a proportional amplifier.Described division circuit is used for division arithmetic is carried out in interchange and d. c. voltage signal, eliminates light intensity and changes the influence that brings to mutual inductor, and it is made up of an AD734 divider.The result of the temperature voltage signal of directly measuring with temperature sensor that described temperature compensation feedback circuit is used for computing machine is demarcated after relatively feeds back to communication channel, in order to the influence of compensation temperature to mutual inductor, it comprises that bias voltage is provided with circuit and amplifier.Described constant-current drive circuit is used to supply with constant current of light emitting diode, and the light source power that is used in the photo-electric current transformer keeps constant, and it is made up of resistance, adjustable resistance and three-terminal regulator block.
The analogue signal processor that is used for magneto-optical current transformer that the present invention proposes, take temperature direct compensation and light source drive current constant current control measure that the temperature problem and the birefringence problem of puzzlement magneto-optical current transformer development are improved, make it have characteristics such as good stability, precision height, temperature effect are little.It can be used for having the magneto-optical current transformer of Faraday effect realization, and it also is applicable to the temperature compensation and the signal Processing of all photoeletric measuring systems, is that use value is arranged very much therefore.Because the photo-electric current transformer is compared with electromagnetic current transducer, a lot of outstanding advantages are arranged, it is the comparatively desirable regeneration product of induction current transformer, and estimate that the photo-electric current transformer can be installed and use in a large number in five to ten years of future in the electrical network of various electric pressures.In addition, except installing in electrical network and using, the photo-electric current transformer also can be used for some other occasion: portable type current is measured; High frequency current measurement; The position of fault in zero sequence current measurement in the electrical network and the definite electrical network.Therefore, this patent of invention has wide practical use.
Description of drawings:
Fig. 1 is an analogue signal processor block diagram of the present invention.
Fig. 2 is the analogue signal processor circuit diagram with temperature compensation function of the present invention.
Fig. 3 is LED constant-current drive circuit figure.
The magneto-optical current transformer ratio performance plot of Fig. 4 for realizing with signal processor of the present invention.
The magneto-optical current transformer angular difference performance plot of Fig. 5 for realizing with signal processor of the present invention.
Below in conjunction with accompanying drawing, introduce content of the present invention in detail:
Fig. 1 is the theory diagram with analogue signal processor of temperature compensation function.Constant-current drive circuit is supplied with constant current source of light emitting diode, the light S that light emitting diode sends
OUTEnter the polarizer by optical fiber and become a branch of polarized light, inject the glass sensing head of making by ZF6, change with the size of conductor current, become intensity levels, obtain S by optical fiber again through analyzer around the detour polarization angle of a circle back polarization state of conductor
INSignal enters photodetector light signal is become electric signal, and this electric signal is divided into direct current and communication channel through prime amplifier, enters the A/D transducer and becomes digital signal by Computer Processing.Directly temperature compensation is realized by fibre optic temperature sensor, the fiber optic temperature sensor head of being made up of gallium arsenide semiconductor material is put near the sensing head glass blocks, it also spreads out of temperature signal by optical fiber, after signal Processing, become voltage signal, entering the A/D transducer compares with the data that influence of demarcation temperature well to magneto-optical current transformer, comparative result is sent into the output that the temperature compensation feedback circuit is regulated communication channel, reaches the purpose of direct compensation.
Fig. 2 is the analogue signal processor circuit diagram with temperature compensation function.Comprise prime amplifier, communication channel, direct current channel, division circuit, temperature compensation feedback circuit five parts among the figure, below respectively each several part is discussed.
(1) design of prime amplifier
Shown in dashed rectangle among Fig. 2 " prime amplifier ", prime amplifier is to have increased a feedback capacity C on the current-to-voltage converter basis
0, the closed loop gain G of prime amplifier
1For: G
1=-R
0This circuit has the characteristics of zero input, output resistance, make photodetector be operated in the short circuit working method, can eliminate the influence that brings owing to PN junction forward current (dark current of photodetector), and make silicon photoelectric diode obtain optimum signal-noise ratio, the signal that is exaggerated only is directly proportional with light intensity.The amplifier that adopts is the ultra-low noise operational amplifier A D OP-27 of Analog Devices Inc.The prime amplifier method for designing is as follows: consider that possible light intensity changes, 1.5V～2.5V is elected in the direct current output of prime amplifier as, determines feedback resistance R according to the size of input photocurrent
0Size, at last according to the frequency range and the feedback resistance R of signal
0Size determine C
0Size.
(2) design of communication channel
After top prime amplifier amplification, under the 1000A electric current, AC compounent also has only a few percent volt, and the enlargement factor of old friend's circulation road need be about 100.The gain amplification of communication channel is mainly born by instrument amplifier AD624, and communication channel also is useful on the bandpass filter of noise reduction and the phase shifter of control phase.A among the figure
HpBe high-pass filtering circuit, A
LpBe low-pass filter circuit, A
PpBe phase shifter circuit.
Select for use instrument amplifier AD624 to amplify main because it has extra high degree of accuracy and common-mode rejection ratio, stable performance and can decide the gain multiple by the interconnection that changes pin, need not insert external component as gain.Use shows that the AD624 instrument amplifier has very strong inhibiting effect to amplifying bandwidth noise in addition.
The passband of bandpass filter is 10Hz～2kHz, is that the voltage-controlled Hi-pass filter of second order of 10Hz and the voltage-controlled low-pass filter of second order that cutoff frequency is 2kHz are formed by cutoff frequency.In fact phase shifter is exactly all-pass filter.Concerning these two parts, device noise has not been a subject matter, and is more typical circuit, does not describe in detail at this.
In addition, A
HpBe a voltage-controlled operational amplifier in VCA610 broadband, its pin one, 8 is respectively positive inverting input, and pin 6,7 is respectively positive-negative power, and pin 3 is voltage-controlled end.When temperature voltage signal when demarcating good temperature to the influencing data and compare of magneto-optical current transformer, draw a voltage signal after the comparison, this signal is supplied with the pin 3 of VCA610 as feedback signal, in order to regulating the output voltage of communication channel, thereby reaches the effect of temperature compensation.
(3) design of direct current amplification channel
Because the direct current output level of prime amplifier has reached 1.5V～2.5V, wherein the consideration of noise is not main.The direct current amplifier main task is further to amplify DC level, reaches the voltage range that the A/D conversion requires, and filtering interchange and noise component.The direct current amplification channel is exactly general low-pass filter, and its cutoff frequency is about 5Hz.
Communication channel among Fig. 2 and direct current channel output V
AC, V
DCEnter the A/D converting unit, carry out digital signal processing.The current signal of magneto-optical current transformer finally is to adopt digital technology to handle and extract by microcomputer.In digital signal processing, at first the AC and DC signal is divided by, after handling through digital filtering, denoising etc. again, compares with the data that influence of predetermined temperature to sensor, realize temperature compensation, thus the analog current signal that output is directly proportional with tested electric current.
(4) division circuit
Shown in dashed rectangle among Fig. 2 " division circuit ", the signal V of communication channel and direct current signal output is arranged
AC, V
DCEnter the division circuit that high precision divider AD734 constitutes simultaneously.Direct current signal connects the X1 end of AD734, and AC signal connects the Z2 end, and X2, Z1, the equal ground connection of Y1, thereby realizing exchanging the function of being divided by with direct current, output signal is: V
OUT=10Z2/X1.Carry out division and handle, its objective is in order to eliminate the influence of light emitting diode light intensity and optical fiber junction loss variation to magneto-optical current transformer
(5) temperature compensation feedback circuit
Feedback circuit is shown in Fig. 2 dotted line unit square frame FEED.From the temperature compensation signal of computing machine output, after the D/A conversion, obtain V
DAAnalog voltage signal, it generally remains on 2mV～2V.V among the figure
+ fBe dc reference signal, generally get 0.1～1V direct current.V
DAAnd V
+ fSignal amplifies 3 pin of FEEDBACK CONTROL VCA610 by the OPA620 sampling relatively later on.V
-fAnd R
F3, R
F4Purpose be make the voltage of control voltage 3 ends can be 0～-change between the 2V.Find out that thus the sensing head variation of temperature will change temperature compensation signal voltage V
DAVariation, and then change V
HpGain, realize the purpose of temperature direct compensation at last.
Fig. 3 is a LED constant current driving circuit.It is stable that the output intensity of light source luminescent diode should keep, and this just requires the drive current of light emitting diode to stablize.The current drives of light emitting diode is made of simple, a reliable constant-current source circuit.Be the constant current source driving circuit that core constitutes with three-terminal regulator block LM317 among the figure.The V of LM317
OutExport a stable 1.27V voltage, thereby guarantee that light emitting diode has a constant electric current.Adjustable resistance is used for regulating the size of drive current among the figure.
The magneto-optical current transformer ratio performance plot of Fig. 4 for realizing with this signal processor.E is a ratio among the figure, and I is tested electric current.In order to represent the dispersed situation of the measurement result of MOCT under different electric currents, the spy repeatedly measures under certain current value, and represents on figure with the form of point, and wherein solid line is 0.2 grade of current transformer ratio limit, and the figure orbicular spot is to measure to compare difference.Can find out from figure: the ratio in 80A～2300A range of current is in the degree of accuracy of 0.2 grade of current transformer defined.
The magneto-optical current transformer angular difference performance plot of Fig. 5 for realizing with this signal processor.ψ is an angular difference among the figure, and I is tested electric current.Wherein, empty circles is 0.5 grade of current transformer angular difference limit, and solid circles is the measured angular difference.Can find out from figure: the angular difference difference in 80A～2300A range of current is in the degree of accuracy of 0.5 grade of current transformer defined.
Therefore, the degree of accuracy that magneto-optical current transformer ratio of realizing with this analogue signal processor and angular difference all are better than 0.5 grade of current transformer defined, it illustrates that this analogue signal processor is that practical, effect temperature compensation is significant.
Claims (1)
1, a kind of analogue signal processor that is used for magneto-optical current transformer, it is characterized in that, this processor comprises prime amplifier, communication channel, direct current channel, division circuit, temperature compensation feedback circuit, light source constant-current drive circuit, described prime amplifier is accepted the electric signal by photodetector output, and with its amplification, it is made up of photodetector, proportional amplifier, resistance and electric capacity; Described communication channel is used for AC signal amplification once more, filtering, phase shift from prime amplifier, thereby obtains the AC signal of 10Hz～2kHz, is made up of AD624 amplifier, low-pass filter, Hi-pass filter and phase shifter; Described direct current channel is used for the signal from prime amplifier is carried out low-pass filtering less than 1Hz, amplifies again, and to produce required d. c. voltage signal, it is made up of a passive low ventilating filter and a proportional amplifier; Described division circuit is used for division arithmetic is carried out in interchange and d. c. voltage signal, eliminates light intensity and changes the influence that brings to mutual inductor, and it is made up of an AD734 divider; The result of the temperature voltage signal of directly measuring with temperature sensor that described temperature compensation feedback circuit is used for computing machine is demarcated after relatively feeds back to communication channel, in order to the influence of compensation temperature to mutual inductor, it by bias voltage circuit is set and amplifier is formed; Described constant-current drive circuit is used to supply with constant current of light emitting diode, and the light source power that is used in the photo-electric current transformer keeps constant, and it is made up of resistance, adjustable resistance and three-terminal regulator block.
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| CN 00105931 CN1119663C (en) | 2000-04-21 | 2000-04-21 | Analogue signal processor for magneto-optical current transformer |
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|---|---|---|---|
| CN 00105931 CN1119663C (en) | 2000-04-21 | 2000-04-21 | Analogue signal processor for magneto-optical current transformer |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1316234C (en) * | 2001-12-18 | 2007-05-16 | 恩德莱斯和豪瑟尔两合公司 | Field device and method for calibrating a field device |
| CN103966023A (en) * | 2014-05-22 | 2014-08-06 | 广西平果华莲科技研究所 | Method for extracting essence from lotus stamens |
| CN104330605A (en) * | 2014-11-07 | 2015-02-04 | 东南大学 | Magnetic control grating light valve based current transformer and bus current detection method |
| CN105190322A (en) * | 2013-03-08 | 2015-12-23 | 迪尔公司 | Method for sensing current in a conductor |
| CN106066397A (en) * | 2016-07-05 | 2016-11-02 | 深圳普门科技有限公司 | A kind of compensation system, method and immunity analysis instrument being applicable to current-output type photomultiplier tube |
| CN109342807A (en) * | 2018-12-17 | 2019-02-15 | 中北大学 | A voltage sensing device and detection method combined with elastic-optical modulation and electro-optical modulation |
| CN112881771A (en) * | 2021-01-18 | 2021-06-01 | 国网湖北省电力有限公司营销服务中心(计量中心) | High-precision high-voltage transformer acquisition system based on phase detection |
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| CN114910718A (en) * | 2022-04-08 | 2022-08-16 | 北京和利时系统工程有限公司 | Fault judgment method and device |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1316234C (en) * | 2001-12-18 | 2007-05-16 | 恩德莱斯和豪瑟尔两合公司 | Field device and method for calibrating a field device |
| US7336068B2 (en) | 2001-12-18 | 2008-02-26 | Endress + Hauser Gmbh + Co. Kg | Field device and method for calibrating a field device |
| CN105190322A (en) * | 2013-03-08 | 2015-12-23 | 迪尔公司 | Method for sensing current in a conductor |
| CN105190322B (en) * | 2013-03-08 | 2018-04-17 | 迪尔公司 | Method for sensing the electric current in conductor |
| CN103966023A (en) * | 2014-05-22 | 2014-08-06 | 广西平果华莲科技研究所 | Method for extracting essence from lotus stamens |
| CN104330605A (en) * | 2014-11-07 | 2015-02-04 | 东南大学 | Magnetic control grating light valve based current transformer and bus current detection method |
| CN106066397A (en) * | 2016-07-05 | 2016-11-02 | 深圳普门科技有限公司 | A kind of compensation system, method and immunity analysis instrument being applicable to current-output type photomultiplier tube |
| CN106066397B (en) * | 2016-07-05 | 2019-10-18 | 深圳普门科技股份有限公司 | A kind of compensation system, method and immunity analysis instrument suitable for current-output type photomultiplier tube |
| CN109342807A (en) * | 2018-12-17 | 2019-02-15 | 中北大学 | A voltage sensing device and detection method combined with elastic-optical modulation and electro-optical modulation |
| CN112881771A (en) * | 2021-01-18 | 2021-06-01 | 国网湖北省电力有限公司营销服务中心(计量中心) | High-precision high-voltage transformer acquisition system based on phase detection |
| CN113295924A (en) * | 2021-05-25 | 2021-08-24 | 中国核动力研究设计院 | Neutron noise measurement method and device suitable for nuclear instrument system with frequency output |
| CN114910718A (en) * | 2022-04-08 | 2022-08-16 | 北京和利时系统工程有限公司 | Fault judgment method and device |
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