CN201498355U - Analog signal processing device of electronic current transformer - Google Patents
Analog signal processing device of electronic current transformer Download PDFInfo
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- CN201498355U CN201498355U CN2009203070320U CN200920307032U CN201498355U CN 201498355 U CN201498355 U CN 201498355U CN 2009203070320 U CN2009203070320 U CN 2009203070320U CN 200920307032 U CN200920307032 U CN 200920307032U CN 201498355 U CN201498355 U CN 201498355U
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Abstract
The utility model relates to an electronic current transformer measuring small current, in particular to an analog signal processing device of an electronic current transformer, belonging to the technical field of measurement of power systems. The technical scheme includes that an output of a sampling coil (101) is connected with a voltage following circuit (102), an output of the voltage following circuit is connected with a programmable amplifying circuit (103), an output of the programmable amplifying circuit is connected with an integrating element (104), an output of the integrating element is connected with a filter element (105), an output of the filter element is connected with a phase regulating element (106), and an output of the phase regulating element is connected with a voltage output circuit (107). The analog signal processing device of an electronic current transformer has the advantages that the analog signal processing device has characteristics of low power consumption, high stability, high precision and the like by utilizing the programmable amplifying technique to resolve power consumption and measurement precision problems of systems, can be applied to the electronic current transformer and a signal processing portion of a weak signal measuring system, and then has extremely high using value.
Description
Affiliated technical field:
The utility model relates to a kind of analog signal processing device of the electronic current mutual inductor of measuring little electric current, particularly electronic current mutual inductor, belongs to the field of measuring technique of electric power system.
Background technology:
The current transformer of electric power system utilization at present adopts electromagnetic current transducer more.Along with the grade of rated voltage of electric power system and increasing substantially of transmission capacity, obviously there is deficiency in electromagnetic current transducer, is difficult to adapt to the needs of modern power systems development.Along with the high speed development of photoelectron technology, Digital Signal Processing, optical fiber communication and intelligence sensor, electronic current mutual inductor has become the ideal substitute of electromagnetic type.Electronic current mutual inductor generally adopts Rogowski (Luo Shi) coil as sensing head, when tested electric current passes through the elementary coiling of coil, because electromagnetic induction effect, will induce the correspondent voltage signal at secondary rolling thread, by the voltage signal that measurement induces, just can obtain the size of tested electric current.Generally consist of the following components by the electronic current mutual inductor of Rogowski coil: sensing head Rogowski coil, high-voltage signal treatment circuit, high-voltage suppling power, Optical Fiber Transmission part, low-voltage signal processing etc. as sensing head.The high-voltage signal treatment circuit is mainly finished functions such as amplification, integration, filtering and phase modulation; because in addition overload protection measure in the measuring process; and background technology all is to adopt two loops to finish to measure and overload protection; therefore the power consumption of high-pressure side is very big; when especially measuring little electric current, the powerup issue of high-pressure side is very much outstanding.Owing to exist transmission delay, filtering link and integral element in the circuit, then output signal is inevitable produces phase shifts with respect to input signal, therefore in order to satisfy standard, must take certain phase compensation measure.The phase modulation scope of phase correction scheme commonly used all is to spend 0 at present--between 180 degree, when regulating the number of degrees, be easy to realize, if but when the adjusting number of degrees are smaller, just be difficult to realize in the 90 degree left and right sides.
The utility model content:
The utility model purpose provides a kind of analog signal processing device of electronic current mutual inductor; utilizing program control amplifying technique to adopt a loop to finish measures and two kinds of functions of overload protection; thereby the power consumption the purpose of this utility model that greatly reduces the high-pressure side signal processing is to propose a kind of electronic current mutual inductor signal processor that is applicable to small current measurement; to reduce power consumption effectively; reduce the pressure of high-voltage suppling power, solve the problems referred to above that background technology exists.
The utility model purpose is to realize by following technical scheme:
The analog signal processing device of electronic current mutual inductor comprises sampling coil, voltage follower circuit, programmable amplifying circuit, integral element, filtering link, phase modulation link, voltage follower circuit, the output of sampling coil connects voltage follower circuit, the output of voltage follower circuit connects programmable amplifying circuit, the output of programmable amplifying circuit connects integral element, the output of integral element connects the filtering link, the output of filtering link connects the phase modulation link, and the output of phase modulation link connects voltage follower circuit.
Said programmable amplifying circuit comprises gets true rms circuit, voltage comparator circuit, inverter and programmable amplifier, the output signal of voltage follower circuit is divided into two-way, one the tunnel connects programmable amplifier, another road connects gets true rms circuit, this circuit output is connected with voltage comparator circuit, the output of voltage comparator circuit is connected with inverter, and the output of reverser connects the control end of programmable amplifier.
Voltage follower circuit has the voltage follow effect, receives the voltage signal that induces from sensing head and it is amplified, and obtains stronger voltage signal; Programmable amplifying circuit is used for signal is further amplified, but multiplication factor is promptly worked as tested electric current in normal range (NR) by the size decision of tested electric current, carry out 20 times of amplifications, if tested current overload then carries out 1 times of amplification to it, this circuit mainly is made of programmable amplifier PGA102; Integrating circuit is used for induced voltage signal is carried out the linear relationship that integration is realized induced voltage and tested electric current; Low-pass filter circuit adopts second order voltage controlled voltage source low-pass filter circuit, to eliminate high-frequency interferencing signal, takes out the following signal of required power frequency 13 subharmonic; Phase compensating circuit adopts two single order all-pass wave filtering circuit to constitute, to realize the phase compensation to measured signal.
The utility model phase modulation link is mainly used in the phase difference that compensation Rogowski coil, integral element, filtering link bring, and by analytical calculation as can be known, the adjustable range of phase compensation link should be at 2 degree--between 10 degree.Therefore phase modulation circuit of the present utility model comprises two and constitutes single order all-pass wave filtering circuit by high precision operating amplifier Max420, and two single order all-pass wave filtering circuit are connected in series, and carry out phase compensation.
The beneficial effects of the utility model:, make it possess characteristics such as low-power consumption, high stability, high accuracy owing to adopt program control amplifying technique that the power problems and the certainty of measurement problem of system are improved; The utility model can be applicable to electronic current mutual inductor, also can be used for the signal processing of some other small-signal measuring system, therefore has very high use value; Because electronic current mutual inductor has the advantage of a lot of uniquenesses for electromagnetic current transducer, be the ideal substitute of electromagnetic current transducer, estimate in various electric pressure invocation point nets, to install in a large number and to use at following 5 to 10 years electronic current mutual inductors.In addition,, can also be used for portable type current and measure except in electrical network, installing and using, position of fault in high frequency current measurement, the electrical network in zero sequence current measurement and the definite electrical network or the like, therefore, this utility model patent is with a wide range of applications.
Description of drawings:
Fig. 1 is a signal processor block diagram of the present utility model.
Among the figure: sampling coil 101, voltage follower circuit 102, programmable amplifying circuit 103, integral element 104, filtering link 105, phase modulation link 106, voltage follower circuit 107.
Fig. 2 is voltage follow of the present utility model, programmable amplifying circuit schematic diagram.
Fig. 3 is an integrating circuit schematic diagram of the present utility model.
Fig. 4 is a filter circuit schematic diagram of the present utility model.
Fig. 5 is a phase modulation circuit schematic diagram of the present utility model.
Embodiment:
Below in conjunction with embodiment, further specify the utility model.
With reference to accompanying drawing 1, the analog signal processing device of electronic current mutual inductor comprises sampling coil 101, voltage follower circuit 102, programmable amplifying circuit 103, integral element 104, filtering link 105, phase modulation link 106, voltage follower circuit 107, the output of sampling coil connects voltage follower circuit, the output of voltage follower circuit connects programmable amplifying circuit, the output of programmable amplifying circuit connects integral element, the output of integral element connects the filtering link, the output of filtering link connects the phase modulation link, and the output of phase modulation link connects voltage follower circuit.
After the voltage signal process voltage follow from sensing head Rogowski (Luo Shi) coil, one road signal outputs to gets true rms circuit, pass through the multiplication factor of removing to control programmable amplifying circuit with the relatively later controlled signal of reference voltage, voltage signal is exported to integral element after programmable amplifying circuit amplifies, to realize the linear relationship of voltage signal and tested current signal, through keeping 13 rd harmonic signal owing to designing requirement behind the integration, therefore analog voltage signal is through the low-pass filter circuit by the second order voltage controlled voltage source, with the filtering high-frequency interferencing signal, signal outputs to the phase modulation link then, so that it is carried out phase compensation, the voltage signal that output at last is directly proportional with tested electric current is observed to Displaying Meter or oscilloscope.
With reference to accompanying drawing 2, comprising voltage follower circuit, get true rms circuit, voltage comparator circuit, reverser, programmable amplifier.
Voltage follower circuit:
As shown in FIG., in order to improve the antijamming capability of sensing head induced signal, and avoid prime that back level signal processing is brought influence, designed the voltage follower that constitutes with high-operational amplifier OP290Z, the characteristics of this circuit are the little and drifts little (temperature is floated, drift little) of imbalance, are suitable for the Testing of Feeble Signals occasion.
Get true rms circuit, voltage comparator circuit, reverser, programmable amplifying circuit:
The sensing head induced signal is through after the voltage follow; for signal is further amplified; and realize that same loop finish normal measurement and overload protection dual-use function; designed programmable amplifying circuit; tested electric current is just often realized 20 times of amplifications to signal, when signal overloading surpasses 20 times of rated current; signal is amplified 1 times, thereby reach the purpose of overload protection.This partial circuit is made of real effective transducer LTC1066, voltage comparator Max907, programmable operational amplifier PGA102.
Voltage follower circuit output signal one tunnel is exported to PGA102, one the tunnel exports to real effective transducer LTC1966, then effective value and the reference voltage of obtaining compared in voltage comparator MAX907, go to control the multiplication factor of programmable amplifying circuit behind result's process inverter SN74AUP1G06 relatively.When tested electric current during less than 100A, the multiplication factor of programmable amplifying circuit is 20 times, belongs to normally measuring; When tested electric current during greater than 100A, the multiplication factor of programmable amplifying circuit is 1, reaches the purpose of overload protection.It is because it has characteristics such as high accuracy, low-power consumption, low temperature drift that this circuit adopts programmable amplifier PGA102.
Concrete connected mode: the voltage signal e (t) of prime sensing head output is input to 2 pin of OP290 in the voltage follower circuit, is exported by 1 pin of OP290 after the voltage follow.This output signal is divided into two-way, one the road is directly inputted to the input signal of 6,7,8 pin of programmable operational amplifier PGA102 as program control amplification, another road is input to 2 pin of LTC1966, then by the 5 pin output of LTC1966 and the corresponding direct voltage U of effective value of input signal
Rms1,3,6, the 8 pin ground connection of LTC1966,4,7 pin connect negative supply and positive supply respectively, 5 pin output voltage U
Rms2 pin and the reference voltage that are input to voltage comparator Max907 compare.
In voltage comparator Max907,2 pin meet U
Rms, 4 pin ground connection, 3 pin meet reference voltage U
Ref, U
RefBe by resistance R
4And R
5Receive+the 5V power supply after dividing potential drop and getting.Because induced voltage signal was 12.5mV when tested electric current was specified 5A, be 25mV after 2 times of amplifications of voltage follower circuit, then when transshipping 20 times the time, voltage is 0.5V after preposition amplification, i.e. reference voltage U
RefBe 0.5V, so R
4, R
5Be respectively 9k Ω and 1k Ω.U
RmsWith U
RefCompare the 1 pin output high-low level signal of back by Max907.Work as U
Rms＜U
Ref, promptly tested electric current is during less than 100A, comparator output high level; Work as U
Rms＞U
Ref, promptly tested electric current is during greater than 100A, the comparator output low level.
The output signal of voltage comparator goes to control the gain of programmable operational amplifier PGA102, for coupled system work, outputs to 1 pin of PGA102 behind the output signal process inverter SN74AUP1G06.
1 pin of programmable operational amplifier PGA102 receives the output signal from the front end inverter, 2,3,4,5 pin ground connection, and 6,7,8 pin receive the output signal from voltage follower circuit, 9,10 connecting resistance R
7And R
6So that multiplication factor is adjusted, 11,12 pin meet adjustable resistance R
8=100k Ω is to be offset adjustment, and 13,16 pin connect negative, positive power supply, and 14 pin are unsettled, the output of 15 pin.
With reference to accompanying drawing 3, integrating circuit, by the principle of Rogowski coil as can be known, because the output voltage of Rogowski coil is directly proportional with the derivative of input current to the time, so need an integrator become I (t) function to be for further processing the di/dt conversion of signals.In order to satisfy the requirement of whole system to integral accuracy, stable operating point selects for use imbalance and temperature to float the approximate integration device that little high accuracy chopped mode operational amplifier Max430 constitutes the band feedback resistance.Desirable integrator is not have resistance R
f, R
fEffect mainly be to prevent that making in the time integrator that the drift owing to operational amplifier brings than the farm labourer blocks.
With reference to accompanying drawing 4, low-pass filter circuit, because the coil-induced voltage signal that goes out the high-frequency noise interference signal can occur inevitably in transmission course, and designing requirement is by 13 subharmonic, so will add the filtering link with filtering interference signals in the analog system.In order to make filter effect better, and little to the influence of phase place, and we have designed the second order voltage controlled voltage source low pass filter based on the Butterworth filter principle.In this second order voltage controlled voltage source low pass filter, what operational amplifier adopted is that high precision operating amplifier Max420 is to improve system accuracy.
With reference to accompanying drawing 5, phase modulation circuit.Owing to exist transmission delay, filtering link and integral element in the circuit, then output signal is inevitable produces phase shifts with respect to input signal, therefore in order to satisfy standard, must take certain phase compensation measure.The phase modulation scope of phase correction scheme commonly used all is to spend 0 at present--between 180 degree, when regulating the number of degrees, be easy to realize, if but when the adjusting number of degrees are smaller, just be difficult to realize in the 90 degree left and right sides.And in native system, the phase modulation link is mainly used in the phase difference that compensation Rogowski coil, integral element, filtering link bring, and by analytical calculation as can be known, the adjustable range of phase compensation link should be at 2 degree--between 10 degree.Therefore, improve in this part.In circuit design, adopt two single order all-pass wave filtering circuit of high precision operating amplifier Max420 formation to connect and carry out phase compensation.
Claims (3)
1. the analog signal processing device of an electronic current mutual inductor, it is characterized in that comprising sampling coil (101), voltage follower circuit (102), programmable amplifying circuit (103), integral element (104), filtering link (10), phase modulation link (106), voltage follower circuit (107), the output of sampling coil connects voltage follower circuit, the output of voltage follower circuit connects programmable amplifying circuit, the output of programmable amplifying circuit connects integral element, the output of integral element connects the filtering link, the output of filtering link connects the phase modulation link, and the output of phase modulation link connects voltage follower circuit.
2. according to the analog signal processing device of the described electronic current mutual inductor of claim 1, it is characterized in that said programmable amplifying circuit comprises gets true rms circuit, voltage comparator circuit, inverter and programmable amplifier, the output signal of voltage follower circuit is divided into two-way, one the tunnel connects programmable amplifier, another road connects gets true rms circuit, this circuit output is connected with voltage comparator circuit, the output of voltage comparator circuit is connected with inverter, and the output of reverser connects the control end of programmable amplifier.
3. according to the analog signal processing device of claim 1 or 2 described electronic current mutual inductors, it is characterized in that said phase modulation circuit comprises two and constitutes single order all-pass wave filtering circuit by high precision operating amplifier Max420, two single order all-pass wave filtering circuit are connected in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203070320U CN201498355U (en) | 2009-07-29 | 2009-07-29 | Analog signal processing device of electronic current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203070320U CN201498355U (en) | 2009-07-29 | 2009-07-29 | Analog signal processing device of electronic current transformer |
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| Publication Number | Publication Date |
|---|---|
| CN201498355U true CN201498355U (en) | 2010-06-02 |
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| CN2009203070320U Expired - Fee Related CN201498355U (en) | 2009-07-29 | 2009-07-29 | Analog signal processing device of electronic current transformer |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103023479A (en) * | 2012-12-14 | 2013-04-03 | 广西星宇智能电气有限公司 | Analog integrator circuit based on rogowski coil current transformer |
| CN103061940A (en) * | 2011-10-24 | 2013-04-24 | 联创汽车电子有限公司 | Acquisition and processing circuit of oil sprayer driving currents |
| CN103558446A (en) * | 2013-11-22 | 2014-02-05 | 国家电网公司 | Overvoltage on-line monitoring system |
| CN103616564A (en) * | 2013-11-23 | 2014-03-05 | 国家电网公司 | Self-adaptation signal conditioning device |
| CN109164287A (en) * | 2018-10-08 | 2019-01-08 | 深圳市艾华迪技术有限公司 | A kind of hollow coil AC current sensor |
| CN109521264A (en) * | 2018-12-29 | 2019-03-26 | 水木源华电气有限公司 | A kind of digital zero sequence current mutual inductor of on-pole switch |
| CN109672423A (en) * | 2018-12-24 | 2019-04-23 | 沈阳工业大学 | Integrated state variable filter |
-
2009
- 2009-07-29 CN CN2009203070320U patent/CN201498355U/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103061940A (en) * | 2011-10-24 | 2013-04-24 | 联创汽车电子有限公司 | Acquisition and processing circuit of oil sprayer driving currents |
| CN103061940B (en) * | 2011-10-24 | 2015-03-18 | 联创汽车电子有限公司 | Acquisition and processing circuit of oil sprayer driving currents |
| CN103023479A (en) * | 2012-12-14 | 2013-04-03 | 广西星宇智能电气有限公司 | Analog integrator circuit based on rogowski coil current transformer |
| CN103558446A (en) * | 2013-11-22 | 2014-02-05 | 国家电网公司 | Overvoltage on-line monitoring system |
| CN103616564A (en) * | 2013-11-23 | 2014-03-05 | 国家电网公司 | Self-adaptation signal conditioning device |
| CN109164287A (en) * | 2018-10-08 | 2019-01-08 | 深圳市艾华迪技术有限公司 | A kind of hollow coil AC current sensor |
| CN109672423A (en) * | 2018-12-24 | 2019-04-23 | 沈阳工业大学 | Integrated state variable filter |
| CN109521264A (en) * | 2018-12-29 | 2019-03-26 | 水木源华电气有限公司 | A kind of digital zero sequence current mutual inductor of on-pole switch |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100602 Termination date: 20100729 |