CN203929849U - Current detection circuit in a kind of electronic type voltage transformer - Google Patents
Current detection circuit in a kind of electronic type voltage transformer Download PDFInfo
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- CN203929849U CN203929849U CN201420280685.5U CN201420280685U CN203929849U CN 203929849 U CN203929849 U CN 203929849U CN 201420280685 U CN201420280685 U CN 201420280685U CN 203929849 U CN203929849 U CN 203929849U
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Abstract
The utility model relates to the current detection circuit in a kind of electronic type voltage transformer.The utility model comprises power module, current detection module, operation amplifier module, PI control module, recommends output module, compensating coil module and current/voltage-converted module.TMR sensor in current detection module detects the changes of magnetic field corresponding with curent change, electric bridge through current detection module is converted to Voltage-output, this voltage is after the differential amplification of operation amplifier module, be input to PI control module adjusted, through recommending output module, realize electric current amplification again, the current signal after amplification drives compensating coil work.Electric current in compensating coil is converted into and the proportional magnitude of voltage of tested electric current through current/voltage-converted module, and this voltage measuring value is measured output.The utility model has been simplified insulation against ground problem, there is highly sensitive, fast response time, nonlinearity is little, magnetic hysteresis is little, good temp characteristic, low in energy consumption, be easy to the characteristics such as microminaturization.
Description
Technical field
The utility model belongs to electric detective technology field, relates to a kind of current detection circuit in electronic type voltage transformer, is mainly used in designing a kind of sensing type electronic type voltage transformer.
Background technology
Intelligent grid is representing the up-to-date direction that power system development is changed, and as the electronic mutual inductor of Power Network Digital, intelligent bottom measurement mechanism, has become the indispensable part of intelligent grid.At present in China's electrical network, primary side information measurement equipment is still taken as the leading factor with traditional electromagnetic transformer, but along with the continuous rising of voltage class of electric power system, the power capacity of transmission is increasing, there is self unsurmountable problem because of sensor mechanism in conventional voltage mutual inductor, and electronic mutual inductor is comprised of sensing element and data processing unit, because its sensor mechanism is advanced, replace traditional electromagnetic transformer to there are many advantages: from performance, improved voltage measurement grade, dynamic range is large; From electric power safety angle, electronic type mutual inductance is because adopting the danger such as inflammable, explosive of oil-insulation, and volume is little, lightweight, floor area that can conservation of power facility.From development, electronic type mutual inductance can provide simulation, numeral output, adapts to electric system to digitizing, intelligent direction development.In related electronic type voltage transformer, by tested voltage, after the resistor assembly dividing potential drop of high-pressure side, voltage signal is converted to the Weak current signal of low-pressure side, realizes the measurement of voltage signal by detecting this Weak current signal.Therefore, Weak current signal deteching circuit is the core of mutual inductor design, is that mutual inductor is realized high sensitivity, response fast, nonlinearity is little, magnetic hysteresis is little, the important leverage of the performance such as good temp characteristic, low in energy consumption, microminaturization.
Summary of the invention
The purpose of this utility model is just to provide a kind of Weak current marking current testing circuit.
The utility model comprises power module, current detection module, operation amplifier module, PI control module, recommends output module, compensating coil module and current/voltage-converted module.
Described power module comprises a LT1461-2.5 chip, an OPA2277 chip and an OP177 chip, wherein, 2 pin of LT1461-2.5 chip are connected with one end of resistance R 4, the other end of resistance R 4 and external power source+15V end is connected, 3 pin of LT1461-2.5 chip are connected with one end of capacitor C 10, the other end of capacitor C 10 respectively with 4 pin of LT1461-2.5 chip, one end of capacitor C 8, one end of capacitor C 9, one end of resistance R 9 is connected with ground terminal, the other end of capacitor C 8 respectively with 6 pin of LT1461-2.5 chip, the other end of capacitor C 9, 3 pin of one end of resistance R 3 and OP177 chip are connected, the other end of resistance R 3 is connected with the other end of resistance R 9 and 3 pin of OPA2277 chip respectively, 2 pin of OP177 chip are connected with one end of resistance R 1 with one end of resistance R 2 respectively, the other end of resistance R 2 is connected with ground terminal, the other end of resistance R 1 is connected with 6 pin of OP177 chip, and as the bias voltage output terminal Vbia of power module, 4 pin of OP177 chip respectively with one end of capacitor C 6 and external power source-15V end is connected, the other end of capacitor C 6 is connected with ground terminal, 7 pin of OP177 chip respectively with one end of capacitor C 1 and external power source+15V end is connected, the other end of capacitor C 1 is connected with ground terminal, 2 pin of OPA2277 chip respectively with one end of resistance R 10, 1 pin of one end of resistance R 6 and OPA2277 chip is connected, 4 pin of OPA2277 chip respectively with one end of capacitor C 7 and external power source-15V end is connected, the other end of capacitor C 7 is connected with ground terminal, 8 pin of OPA2277 chip respectively with one end of capacitor C 11 and external power source+15V end is connected, the other end of capacitor C 11 is connected with ground terminal, the other end of resistance R 10 is connected with one end of resistance R 11 and 6 pin of OPA2277 chip respectively, the other end of resistance R 11 is connected with one end of resistance R 8 and 7 pin of OPA2277 chip respectively, the other end of resistance R 8 is connected with 1 pin of adjustable resistance XR2, 2 pin of adjustable resistance XR2 are connected with the other end of resistance R 6, 3 pin of adjustable resistance XR2 are as the reference voltage output terminal REF of power module.
Described current detection module comprises a MMLD47F chip, 6 pin of MMLD47F chip are connected with the bias voltage output terminal Vbia of power module, 3 pin of MMLD47F chip are connected with ground terminal, 5 pin of MMLD47F chip are as the forward voltage output terminal V+ of current detection module, and 4 pin of MMLD47F chip are as the negative voltage output terminal V-of current detection module.
Described operation amplifier module comprises first TL081 chip, second TL081 chip and the 3rd TL081 chip, wherein, one end of resistance R 12 is connected with the forward voltage output terminal V+ of current detection module, the other end of resistance R 12 is connected with 3 pin of first TL081 chip, 7 pin of first TL081 chip respectively with one end of capacitor C 13 and external power source+15V end is connected, the other end of capacitor C 13 is connected with ground terminal, 4 pin of first TL081 chip respectively with one end of capacitor C 14 and external power source-15V end is connected, the other end of capacitor C 14 is connected with ground terminal, 2 pin of first TL081 chip are connected with one end of resistance R 16 with one end of resistance R 15 respectively, the other end of resistance R 15 is connected with one end of resistance R 13 and 6 pin of first TL081 chip respectively, the other end of resistance R 13 is connected with 3 pin of the 3rd TL081 chip with one end of resistance R 14 respectively, the other end of resistance R 14 is connected with ground terminal, the other end of resistance R 16 is connected with one end of resistance R 17 and 2 pin of second TL081 chip respectively, one end of resistance R 18 is connected with the negative voltage output terminal V-of current detection module, the other end of resistance R 18 is connected with 3 pin of second TL081 chip, 7 pin of second TL081 chip respectively with one end of capacitor C 19 and external power source+15V end is connected, the other end of capacitor C 19 is connected with ground terminal, 4 pin of second TL081 chip respectively with one end of capacitor C 20 and external power source-15V end is connected, the other end of capacitor C 20 is connected with ground terminal, the other end of resistance R 17 is connected with one end of resistance R 19 and 6 pin of second TL081 chip respectively, the other end of resistance R 19 is connected with 2 pin of the 3rd TL081 chip with one end of resistance R 20 respectively, 7 pin of the 3rd TL081 chip respectively with one end of capacitor C 15 and external power source+15V end is connected, the other end of capacitor C 15 is connected with ground terminal, 4 pin of the 3rd TL081 chip respectively with one end of capacitor C 17 and external power source-15V end is connected, the other end of capacitor C 17 is connected with ground terminal, the other end of resistance R 20 is connected with 6 pin of the 3rd TL081 chip, and as the output terminal TMR_OUT of operation amplifier module.
Described PI control module comprises an OP37 chip, wherein, one end of resistance R 23 is connected with the reference voltage output terminal REF of power module, the other end of resistance R 23 is connected with 3 pin of OP37 chip, one end of resistance R 25 is connected with one end of capacitor C 16 with the output terminal TMR_OUT of operation amplifier module respectively, the other end of resistance R 25 respectively with the other end of capacitor C 16, 2 pin of OP37 chip, one end of capacitor C 27 is connected with one end of capacitor C 30, the other end of capacitor C 30 is connected with one end of resistance R 30, the other end of capacitor C 27 respectively with the other end of resistance R 30, 6 pin of OP37 chip are connected with one end of resistance R 38, 7 pin of OP37 chip respectively with one end of capacitor C 21 and external power source+15V end is connected, the other end of capacitor C 21 is connected with ground terminal, 4 pin of OP37 chip respectively with one end of capacitor C 23 and external power source-15V end is connected, the other end of capacitor C 23 is connected with ground terminal, the other end of resistance R 38 is as the PI output terminal PI_OUT of PI control module.
The described output module of recommending comprises a Darlington transistor BCV26 and a Darlington transistor BCV27, wherein, 1 pin of Darlington transistor BCV26 is connected with one end of resistance R 29 with the negative pole of diode D4 respectively, 2 pin of Darlington transistor BCV26 respectively with the other end of resistance R 29 and external power source-15V end is connected, 3 pin of Darlington transistor BCV26 are connected with one end of resistance R 24, the positive pole of diode D4 is connected with the negative pole of diode D3, the positive pole of diode D3 is connected with the negative pole of diode D2 and the PI output terminal PI_OUT of PI control module respectively, the positive pole of diode D2 is connected with the negative pole of diode D1, the positive pole of diode D1 is connected with 1 pin of adjustable resistance XR1, 2 pin of adjustable resistance XR1 respectively with 3 pin of adjustable resistance XR1, 1 pin of Darlington transistor BCV27 is connected with one end of resistance R 21, the other end of resistance R 21 respectively with 2 pin of Darlington transistor BCV27 and external power source+15V end is connected, 3 pin of Darlington transistor BCV27 are connected with one end of resistance R 22, the other end of resistance R 22 is connected with the other end of resistance R 24 respectively, and recommend output terminal COIL_IN as what recommend output module.
Described compensating coil module comprises the compensating coil A1 of 600 circles; Wherein, one end of compensating coil A1 is connected with the output terminal COIL_IN that recommends that recommends output module, and the other end of compensating coil A1 is the output terminal COIL_OUT of coil module by way of compensation.
Described current/voltage-converted module comprises the 4th TL081 chip, wherein, 2 pin of the 4th TL081 chip respectively with the output terminal COIL_OUT of compensating coil module, one end of resistance R 27 is connected with one end of capacitor C 33, 3 pin of the 4th TL081 chip are connected with ground terminal, 7 pin of the 4th TL081 chip respectively with one end of capacitor C 29 and external power source+15V end is connected, the other end of capacitor C 29 is connected with ground terminal, 4 pin of the 4th TL081 chip respectively with one end of capacitor C 31 and external power source-15V end is connected, the other end of capacitor C 31 is connected with ground terminal, the other end of resistance R 27 respectively with the other end of capacitor C 33, 6 pin of the 4th TL081 chip are connected with the voltage output end VOUT of current/voltage-converted module, voltage output end VOUT institute's output voltage and the tested electric current of current/voltage-converted module are proportional.
Principle of work of the present utility model: connect working power, when input current is zero, adjust the reference voltage output of power module, guarantee system magnetic flux balance, in zero magnetic flux state.When having electric current input, system enters detected state, the variation of electric current has brought the variation of environmental magnetic field, TMR sensor in current detection module detects after the changes of magnetic field corresponding with curent change, through the Wheatstone of current detection module electric bridge, be converted to Voltage-output, this voltage is after the differential amplification of operation amplifier module, be input to PI control module adjusted, through recommending output module, realize electric current amplification again, current signal after amplification drives compensating coil work, the magnetic field equal and opposite in direction that the magnetic field that compensating coil produces and tested electric current produce, opposite direction, making the total magnetic flux that TMR electric bridge is responded to is zero, realizing zero magnetic flux closed loop detects.Electric current in compensating coil is converted into and the proportional magnitude of voltage of tested electric current through current/voltage-converted module, and this voltage measuring value is the measurement output of utility model.
The detectability of the Wheatstone electric bridge that the utility model utilization consists of TMR sensor to Weak current signal, converting the detection of busbar voltage to it proportional little current signal detects, because of low-pressure side above earth potential very low, greatly simplified insulation against ground problem, and this utility model is the core of voltage transformer (VT) design, there is highly sensitive, fast response time, nonlinearity is little, magnetic hysteresis is little, good temp characteristic, low in energy consumption, be easy to the characteristics such as microminaturization.
Accompanying drawing explanation
Fig. 1 is the utility model theory structure schematic diagram;
Fig. 2 is power module 1 schematic diagram;
Fig. 3 is current detection module 2 schematic diagram;
Fig. 4 is operation amplifier module 3 schematic diagram;
Fig. 5 is PI control module 4 schematic diagram;
Fig. 6 is for recommending output module 5 schematic diagram;
Fig. 7 is compensating coil module 6 schematic diagram;
Fig. 8 is current/voltage-converted module 7 schematic diagram.
Embodiment
As shown in Figure 1, the current detection circuit in electronic type voltage transformer comprise interconnection power module 1, current detection module 2, operation amplifier module 3, PI control module 4, recommend output module 5, compensating coil module 6 and current/voltage-converted module 7.Each module+15V and-15V working power provides by external power source.
Described power module comprises a LT1461-2.5 chip, an OPA2277 chip and an OP177 chip.Wherein, LT1461-2.5 chip provides the reference power supply of 2.5V; The 2.5V that LT1461-2.5 chip provides outputs to the bias voltage output terminal Vbia of power module after OP177 chip is amplified to 5V, outputs to current detection module, for Wheatstone electric bridge provides bias voltage through Vbia end; The 2.5V that LT1461-2.5 chip provides, after OPA2277 chip is followed, then outputs to the reference voltage output terminal REF of power module by electric resistance partial pressure adjustment, output to PI control module, for PI control module provides reference voltage through REF end.
Current detection module comprises a MMLD47F chip, and this chip is the Wheatstone electric bridge consisting of four TMR sensors.Wherein, 6 pin of MMLD47F chip are connected with the bias voltage output terminal Vbia of power module, obtain bias voltage; 5 pin of MMLD47F chip produce the output of electric bridge forward, and output to the forward voltage output terminal V+ of current detection module, and 4 pin of MMLD47F chip produce the output of electric bridge negative sense, and output to the negative voltage output terminal V-of current detection module.Through the forward voltage output terminal V+ of current detection module and the negative voltage output terminal V-of current detection module, output to operation amplifier module.
Operation amplifier module comprises first TL081 chip, second TL081 chip and the 3rd TL081 chip.Wherein, the voltage that the forward voltage output terminal V+ of current detection module produces, is input to 3 pin of first TL081 chip, through first TL081 chip, carries out after voltage follow, is input to 3 pin of the 3rd TL081 chip; The voltage that the negative voltage output terminal V-of current detection module produces, is input to 3 pin of second TL081 chip, through second TL081 chip, carries out after voltage follow, is input to 2 pin of the 3rd TL081 chip; After the 3rd TL081 chip amplifies the signal differential of 3 pin by the 3rd TL081 chip, 2 pin inputs, output to the output terminal TMR_OUT of operation amplifier module, through output terminal TMR_OUT, output to PI control module.
PI control module comprises an OP37 chip.Wherein, the reference voltage output terminal REF output reference voltage of power module, to 3 pin of OP37 chip, is used for adjusting the OFFSET that detects output; The differential amplification signal of the output terminal TMR_OUT output of operation amplifier module, be input to 2 pin of OP37 chip, through the error of OP37 chip, amplify and add RC corrective network and realize the PI output terminal PI_OUT that PI controlled and outputed to PI control module, through PI output terminal PI_OUT, output to and recommend output module.
Recommend output module and comprise a Darlington transistor BCV26 and a Darlington transistor BCV27.Wherein, the PI output terminal PI_OUT of PI control module outputs to 1 pin of a Darlington transistor BCV26 and 1 pin of a Darlington transistor BCV27 simultaneously, through a Darlington transistor BCV26 and a Darlington transistor BCV27, realizing electric current recommends after amplification, output to recommend output module recommend output terminal COIL_IN, through recommending output terminal COIL_IN, output to compensating coil module.
Compensating coil module comprises the compensating coil of 600 circles.Wherein, that recommends output module recommends output terminal COIL_IN output current to one end of compensating coil, through compensating coil, produce the magnetic field equal and opposite in direction producing with working current, the compensating field of opposite direction, making the total magnetic flux that TMR electric bridge is responded to is zero, realizes zero magnetic flux closed loop and detects.The other end of compensating coil outputs to the output terminal COIL_OUT of compensating coil module, through output terminal COIL_OUT, outputs to current/voltage-converted module.
Current/voltage-converted module comprises the 4th TL081 chip.Wherein, 2 pin of four TL081 chips of output terminal COIL_OUT output current to the of compensating coil module, through the 4th TL081 chip, be converted to voltage, and export this voltage to the voltage output end VOUT of current/voltage-converted module, voltage output end VOUT institute's output voltage and tested electric current are proportional, i.e. measurement output of the present utility model.
Each module+15V and-15V working power provides by external power source.
As shown in Figure 2, power module 1 comprises a LT1461-2.5 chip, an OPA2277 chip and an OP177 chip.Wherein, 2 pin of LT1461-2.5 chip are connected with one end of resistance R 4, the other end of resistance R 4 and external power source+15V end is connected, 3 pin of LT1461-2.5 chip are connected with one end of capacitor C 10, the other end of capacitor C 10 respectively with 4 pin of LT1461-2.5 chip, one end of capacitor C 8, one end of capacitor C 9, one end of resistance R 9 is connected with ground terminal, the other end of capacitor C 8 respectively with 6 pin of LT1461-2.5 chip, the other end of capacitor C 9, 3 pin of one end of resistance R 3 and OP177 chip are connected, the other end of resistance R 3 is connected with the other end of resistance R 9 and 3 pin of OPA2277 chip respectively, 2 pin of OP177 chip are connected with one end of resistance R 1 with one end of resistance R 2 respectively, the other end of resistance R 2 is connected with ground terminal, the other end of resistance R 1 is connected with 6 pin of OP177 chip and the bias voltage output terminal Vbia of power module 1 respectively, bias voltage output terminal Vbia is connected with 6 pin of the MMLD47F chip of current detection module 2, 4 pin of OP177 chip respectively with one end of capacitor C 6 and external power source-15V end is connected, the other end of capacitor C 6 is connected with ground terminal, 7 pin of OP177 chip respectively with one end of capacitor C 1 and external power source+15V end is connected, the other end of capacitor C 1 is connected with ground terminal, 2 pin of OPA2277 chip respectively with one end of resistance R 10, 1 pin of one end of resistance R 6 and OPA2277 chip is connected, 4 pin of OPA2277 chip respectively with one end of capacitor C 7 and external power source-15V end is connected, the other end of capacitor C 7 is connected with ground terminal, 8 pin of OPA2277 chip respectively with one end of capacitor C 11 and external power source+15V end is connected, the other end of capacitor C 11 is connected with ground terminal, the other end of resistance R 10 is connected with one end of resistance R 11 and 6 pin of OPA2277 chip respectively, the other end of resistance R 11 is connected with one end of resistance R 8 and 7 pin of OPA2277 chip respectively, the other end of resistance R 8 is connected with 1 pin of adjustable resistance XR2, 2 pin of adjustable resistance XR2 are connected with the other end of resistance R 6, 3 pin of adjustable resistance XR2 are connected with the reference voltage output terminal REF of power module 1, reference voltage output terminal REF is connected with one end of the resistance R 23 of PI control module 4.
As shown in Figure 3, current detection module 2 comprises a MMLD47F chip, and this chip is the Wheatstone electric bridge consisting of four TMR sensors.Wherein, 6 pin of MMLD47F chip are connected with the bias voltage output terminal Vbia of power module 1,3 pin of MMLD47F chip are connected with ground terminal, 5 pin of MMLD47F chip are connected with the forward voltage output terminal V+ of current detection module 2,4 pin of MMLD47F chip are connected with the negative voltage output terminal V-of current detection module 2, the forward voltage output terminal V+ of current detection module 2 is connected with one end of the resistance R 12 of operation amplifier module 3, and the negative voltage output terminal V-of current detection module 2 is connected with one end of the resistance R 18 of operation amplifier module 3.
As shown in Figure 4, operation amplifier module 3 comprises first TL081 chip, second TL081 chip and the 3rd TL081 chip.Wherein, one end of resistance R 12 is connected with the forward voltage output terminal V+ of current detection module 2, the other end of resistance R 12 is connected with 3 pin of first TL081 chip, 7 pin of first TL081 chip respectively with one end of capacitor C 13 and external power source+15V end is connected, the other end of capacitor C 13 is connected with ground terminal, 4 pin of first TL081 chip respectively with one end of capacitor C 14 and external power source-15V end is connected, the other end of capacitor C 14 is connected with ground terminal, 2 pin of first TL081 chip are connected with one end of resistance R 16 with one end of resistance R 15 respectively, the other end of resistance R 15 is connected with one end of resistance R 13 and 6 pin of first TL081 chip respectively, the other end of resistance R 13 is connected with 3 pin of the 3rd TL081 chip with one end of resistance R 14 respectively, the other end of resistance R 14 is connected with ground terminal, the other end of resistance R 16 is connected with one end of resistance R 17 and 2 pin of second TL081 chip respectively, one end of resistance R 18 is connected with the negative voltage output terminal V-of current detection module 2, the other end of resistance R 18 is connected with 3 pin of second TL081 chip, 7 pin of second TL081 chip respectively with one end of capacitor C 19 and external power source+15V end is connected, the other end of capacitor C 19 is connected with ground terminal, 4 pin of second TL081 chip respectively with one end of capacitor C 20 and external power source-15V end is connected, the other end of capacitor C 20 is connected with ground terminal, the other end of resistance R 17 is connected with one end of resistance R 19 and 6 pin of second TL081 chip respectively, the other end of resistance R 19 is connected with 2 pin of the 3rd TL081 chip with one end of resistance R 20 respectively, 7 pin of the 3rd TL081 chip respectively with one end of capacitor C 15 and external power source+15V end is connected, the other end of capacitor C 15 is connected with ground terminal, 4 pin of the 3rd TL081 chip respectively with one end of capacitor C 17 and external power source-15V end is connected, the other end of capacitor C 17 is connected with ground terminal, the other end of resistance R 20 is connected with 6 pin of the 3rd TL081 chip and the output terminal TMR_OUT of operation amplifier module 3 respectively, the output terminal TMR_OUT of operation amplifier module 3 is connected with one end of the resistance R 25 of PI control module 4.
As shown in Figure 5, PI control module 4 comprises an OP37 chip.Wherein, one end of resistance R 23 is connected with the reference voltage output terminal REF of power module 1, the other end of resistance R 23 is connected with 3 pin of OP37 chip, one end of resistance R 25 is connected with one end of capacitor C 16 with the output terminal TMR_OUT of operation amplifier module 3 respectively, the other end of resistance R 25 respectively with the other end of capacitor C 16, 2 pin of OP37 chip, one end of capacitor C 27 is connected with one end of capacitor C 30, the other end of capacitor C 30 is connected with one end of resistance R 30, the other end of capacitor C 27 respectively with the other end of resistance R 30, 6 pin of OP37 chip are connected with one end of resistance R 38, 7 pin of OP37 chip respectively with one end of capacitor C 21 and external power source+15V end is connected, the other end of capacitor C 21 is connected with ground terminal, 4 pin of OP37 chip respectively with one end of capacitor C 23 and external power source-15V end is connected, the other end of capacitor C 23 is connected with ground terminal, the other end of resistance R 38 is connected with the PI output terminal PI_OUT of PI control module 4, the PI output terminal PI_OUT of PI control module 4 is connected with the one end of recommending the diode D2 of output module 5.
As shown in Figure 6, described in, recommend output module 5 and comprise a Darlington transistor BCV26 and a Darlington transistor BCV27.Wherein, 1 pin of Darlington transistor BCV26 is connected with one end of resistance R 29 with the negative pole of diode D4 respectively, 2 pin of Darlington transistor BCV26 respectively with the other end of resistance R 29 and external power source-15V end is connected, 3 pin of Darlington transistor BCV26 are connected with one end of resistance R 24, the positive pole of diode D4 is connected with the negative pole of diode D3, the positive pole of diode D3 is connected with the negative pole of diode D2 and the PI output terminal PI_OUT of PI control module respectively, the positive pole of diode D2 is connected with the negative pole of diode D1, the positive pole of diode D1 is connected with 1 pin of adjustable resistance XR1, 2 pin of adjustable resistance XR1 respectively with 3 pin of adjustable resistance XR1, 1 pin of Darlington transistor BCV27 is connected with one end of resistance R 21, the other end of resistance R 21 respectively with 2 pin of Darlington transistor BCV27 and external power source+15V end is connected, 3 pin of Darlington transistor BCV27 are connected with one end of resistance R 22, the other end of resistance R 22 is connected with the other end of resistance R 24 respectively, and recommend output terminal COIL_IN as what recommend output module.
As shown in Figure 7, compensating coil module 6 comprises the compensating coil A1 of 600 circles.Wherein, one end of compensating coil A1 is connected with the output terminal COIL_IN that recommends that recommends output module 5, the other end of compensating coil A1 is connected with the output terminal COIL_OUT of compensating coil module 6, and the output terminal COIL_OUT of compensating coil module 6 is connected with 2 pin of the 4th TL081 chip of current/voltage-converted module 7.
As shown in Figure 8, current/voltage-converted module 7 comprises the 4th TL081 chip.Wherein, 2 pin of the 4th TL081 chip respectively with the output terminal COIL_OUT of compensating coil module 6, one end of resistance R 27 is connected with one end of capacitor C 33, 3 pin of the 4th TL081 chip are connected with ground terminal, 7 pin of the 4th TL081 chip respectively with one end of capacitor C 29 and external power source+15V end is connected, the other end of capacitor C 29 is connected with ground terminal, 4 pin of the 4th TL081 chip respectively with one end of capacitor C 31 and external power source-15V end is connected, the other end of capacitor C 31 is connected with ground terminal, the other end of resistance R 27 respectively with the other end of capacitor C 33, 6 pin of the 4th TL081 chip are connected with the voltage output end VOUT of current/voltage-converted module 7, voltage output end VOUT institute's output voltage and the tested electric current of current/voltage-converted module 7 are proportional, be measurement output of the present utility model.
The utility model course of work is as follows:
(1) connect working power, outside+15V and-15V power supply provides working power for each module.
(2) making input current is zero, and by adjusting the adjustable resistance XR2 of power module 1, the voltage that makes the voltage output end VOUT of current/voltage-converted module 7 is zero, guarantees in the situation that zero current is inputted, and system is in zero magnetic flux state.
Adjustment process is as follows: after the signal that current detection module 2 detects is amplified by operation amplifier module 3, through the output terminal TMR_OUT of operation amplifier module 3, output to one end of the resistance R 25 of PI control module 4, through the other end of resistance R 25, be transferred to again 2 pin of the OP37 chip of PI control module 4, at zero current input state, the voltage theoretical value that 2 pin of the OP37 chip of PI control module 4 get is zero, but due to the effect of environmental magnetic field, often in non-zero status.Therefore, by adjusting the adjustable resistance XR2 of power module 1, change the voltage of the reference voltage output terminal REF that adjusts power module 1, this voltage outputs to one end of the resistance R 23 of PI control module 4 through adjusting the reference voltage output terminal REF end of power module 1, through the other end of resistance R 23, be transferred to again 3 pin of the OP37 chip of PI control module 4, when when adjusting the adjustable resistance XR2 of power module 1 and make 2 pin of OP37 chip of PI control module 4 and the voltage of 3 pin reach balance, the PI output terminal PI_OUT of PI control module 4 is output as zero.So outputing to, the no-voltage of the PI output terminal PI_OUT of PI control module 4 recommends output module 5, through recommending the output terminal COIL_IN that recommends of output module 5, export zero current to compensating coil module 6, through the output terminal COIL_OUT of compensating coil module 6, output to after current/voltage-converted module 7, the magnitude of voltage that modular converter 7 voltage output end VOUT export is zero again.
(3) when having electric current input, system enters detected state, the variation of electric current has brought the variation in magnetic field, TMR sensor in current detection module 2 detects after the changes of magnetic field corresponding with curent change, through the Wheatstone of current detection module 2 electric bridge, be converted to Voltage-output, one end of resistance R 12 and one end of resistance R 18 that this voltage outputs to respectively operation amplifier module 3 by forward voltage output terminal V+ and the negative voltage output terminal V-of current detection module 2, after the differential amplification of operation amplifier module, by the output terminal TMR_OUT of operation amplifier module 3, outputed to one end of the resistance R 25 of PI control module 4, through the other end of resistance R 25, be transferred to again 2 pin of the OP37 chip of PI control module 4, form pressure reduction with the reference voltage of 3 pin inputs of the OP37 chip of PI control module 4, after this pressure reduction is adjusted by PI control module 4, output to and recommend output module 5 and recommend amplification, through what recommend output module 5, recommend electric current after output terminal COIL_IN output is amplified to compensating coil module 6, output terminal COIL_OUT through compensating coil module 6 outputs to current/voltage-converted module 7 again, the voltage output end VOUT of last modular converter 7 has obtained and the proportional magnitude of voltage of tested electric current, this magnitude of voltage is measurement output of the present utility model.Wherein, magnetic field equal and opposite in direction, opposite direction that the magnetic field that compensating coil produces and tested electric current produce, making the total magnetic flux that TMR electric bridge is responded to is zero, realizes zero magnetic flux closed loop and detects.
Claims (1)
1. the current detection circuit in electronic type voltage transformer, comprises power module, current detection module, operation amplifier module, PI control module, recommends output module, compensating coil module and current/voltage-converted module, it is characterized in that:
Described power module comprises a LT1461-2.5 chip, an OPA2277 chip and an OP177 chip, wherein, 2 pin of LT1461-2.5 chip are connected with one end of resistance R 4, the other end of resistance R 4 and external power source+15V end is connected, 3 pin of LT1461-2.5 chip are connected with one end of capacitor C 10, the other end of capacitor C 10 respectively with 4 pin of LT1461-2.5 chip, one end of capacitor C 8, one end of capacitor C 9, one end of resistance R 9 is connected with ground terminal, the other end of capacitor C 8 respectively with 6 pin of LT1461-2.5 chip, the other end of capacitor C 9, 3 pin of one end of resistance R 3 and OP177 chip are connected, the other end of resistance R 3 is connected with the other end of resistance R 9 and 3 pin of OPA2277 chip respectively, 2 pin of OP177 chip are connected with one end of resistance R 1 with one end of resistance R 2 respectively, the other end of resistance R 2 is connected with ground terminal, the other end of resistance R 1 is connected with 6 pin of OP177 chip, and as the bias voltage output terminal Vbia of power module, 4 pin of OP177 chip respectively with one end of capacitor C 6 and external power source-15V end is connected, the other end of capacitor C 6 is connected with ground terminal, 7 pin of OP177 chip respectively with one end of capacitor C 1 and external power source+15V end is connected, the other end of capacitor C 1 is connected with ground terminal, 2 pin of OPA2277 chip respectively with one end of resistance R 10, 1 pin of one end of resistance R 6 and OPA2277 chip is connected, 4 pin of OPA2277 chip respectively with one end of capacitor C 7 and external power source-15V end is connected, the other end of capacitor C 7 is connected with ground terminal, 8 pin of OPA2277 chip respectively with one end of capacitor C 11 and external power source+15V end is connected, the other end of capacitor C 11 is connected with ground terminal, the other end of resistance R 10 is connected with one end of resistance R 11 and 6 pin of OPA2277 chip respectively, the other end of resistance R 11 is connected with one end of resistance R 8 and 7 pin of OPA2277 chip respectively, the other end of resistance R 8 is connected with 1 pin of adjustable resistance XR2, 2 pin of adjustable resistance XR2 are connected with the other end of resistance R 6, 3 pin of adjustable resistance XR2 are as the reference voltage output terminal REF of power module,
Described current detection module comprises a MMLD47F chip, 6 pin of MMLD47F chip are connected with the bias voltage output terminal Vbia of power module, 3 pin of MMLD47F chip are connected with ground terminal, 5 pin of MMLD47F chip are as the forward voltage output terminal V+ of current detection module, and 4 pin of MMLD47F chip are as the negative voltage output terminal V-of current detection module;
Described operation amplifier module comprises first TL081 chip, second TL081 chip and the 3rd TL081 chip, wherein, one end of resistance R 12 is connected with the forward voltage output terminal V+ of current detection module, the other end of resistance R 12 is connected with 3 pin of first TL081 chip, 7 pin of first TL081 chip respectively with one end of capacitor C 13 and external power source+15V end is connected, the other end of capacitor C 13 is connected with ground terminal, 4 pin of first TL081 chip respectively with one end of capacitor C 14 and external power source-15V end is connected, the other end of capacitor C 14 is connected with ground terminal, 2 pin of first TL081 chip are connected with one end of resistance R 16 with one end of resistance R 15 respectively, the other end of resistance R 15 is connected with one end of resistance R 13 and 6 pin of first TL081 chip respectively, the other end of resistance R 13 is connected with 3 pin of the 3rd TL081 chip with one end of resistance R 14 respectively, the other end of resistance R 14 is connected with ground terminal, the other end of resistance R 16 is connected with one end of resistance R 17 and 2 pin of second TL081 chip respectively, one end of resistance R 18 is connected with the negative voltage output terminal V-of current detection module, the other end of resistance R 18 is connected with 3 pin of second TL081 chip, 7 pin of second TL081 chip respectively with one end of capacitor C 19 and external power source+15V end is connected, the other end of capacitor C 19 is connected with ground terminal, 4 pin of second TL081 chip respectively with one end of capacitor C 20 and external power source-15V end is connected, the other end of capacitor C 20 is connected with ground terminal, the other end of resistance R 17 is connected with one end of resistance R 19 and 6 pin of second TL081 chip respectively, the other end of resistance R 19 is connected with 2 pin of the 3rd TL081 chip with one end of resistance R 20 respectively, 7 pin of the 3rd TL081 chip respectively with one end of capacitor C 15 and external power source+15V end is connected, the other end of capacitor C 15 is connected with ground terminal, 4 pin of the 3rd TL081 chip respectively with one end of capacitor C 17 and external power source-15V end is connected, the other end of capacitor C 17 is connected with ground terminal, the other end of resistance R 20 is connected with 6 pin of the 3rd TL081 chip, and as the output terminal TMR_OUT of operation amplifier module,
Described PI control module comprises an OP37 chip, wherein, one end of resistance R 23 is connected with the reference voltage output terminal REF of power module, the other end of resistance R 23 is connected with 3 pin of OP37 chip, one end of resistance R 25 is connected with one end of capacitor C 16 with the output terminal TMR_OUT of operation amplifier module respectively, the other end of resistance R 25 respectively with the other end of capacitor C 16, 2 pin of OP37 chip, one end of capacitor C 27 is connected with one end of capacitor C 30, the other end of capacitor C 30 is connected with one end of resistance R 30, the other end of capacitor C 27 respectively with the other end of resistance R 30, 6 pin of OP37 chip are connected with one end of resistance R 38, 7 pin of OP37 chip respectively with one end of capacitor C 21 and external power source+15V end is connected, the other end of capacitor C 21 is connected with ground terminal, 4 pin of OP37 chip respectively with one end of capacitor C 23 and external power source-15V end is connected, the other end of capacitor C 23 is connected with ground terminal, the other end of resistance R 38 is as the PI output terminal PI_OUT of PI control module,
The described output module of recommending comprises a Darlington transistor BCV26 and a Darlington transistor BCV27, wherein, 1 pin of Darlington transistor BCV26 is connected with one end of resistance R 29 with the negative pole of diode D4 respectively, 2 pin of Darlington transistor BCV26 respectively with the other end of resistance R 29 and external power source-15V end is connected, 3 pin of Darlington transistor BCV26 are connected with one end of resistance R 24, the positive pole of diode D4 is connected with the negative pole of diode D3, the positive pole of diode D3 is connected with the negative pole of diode D2 and the PI output terminal PI_OUT of PI control module respectively, the positive pole of diode D2 is connected with the negative pole of diode D1, the positive pole of diode D1 is connected with 1 pin of adjustable resistance XR1, 2 pin of adjustable resistance XR1 respectively with 3 pin of adjustable resistance XR1, 1 pin of Darlington transistor BCV27 is connected with one end of resistance R 21, the other end of resistance R 21 respectively with 2 pin of Darlington transistor BCV27 and external power source+15V end is connected, 3 pin of Darlington transistor BCV27 are connected with one end of resistance R 22, the other end of resistance R 22 is connected with the other end of resistance R 24 respectively, and recommend output terminal COIL_IN as what recommend output module,
Described compensating coil module comprises the compensating coil A1 of 600 circles; Wherein, one end of compensating coil A1 is connected with the output terminal COIL_IN that recommends that recommends output module, and the other end of compensating coil A1 is the output terminal COIL_OUT of coil module by way of compensation;
Described current/voltage-converted module comprises the 4th TL081 chip, wherein, 2 pin of the 4th TL081 chip respectively with the output terminal COIL_OUT of compensating coil module, one end of resistance R 27 is connected with one end of capacitor C 33, 3 pin of the 4th TL081 chip are connected with ground terminal, 7 pin of the 4th TL081 chip respectively with one end of capacitor C 29 and external power source+15V end is connected, the other end of capacitor C 29 is connected with ground terminal, 4 pin of the 4th TL081 chip respectively with one end of capacitor C 31 and external power source-15V end is connected, the other end of capacitor C 31 is connected with ground terminal, the other end of resistance R 27 respectively with the other end of capacitor C 33, 6 pin of the 4th TL081 chip are connected with the voltage output end VOUT of current/voltage-converted module, voltage output end VOUT institute's output voltage and the tested electric current of current/voltage-converted module are proportional.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420280685.5U CN203929849U (en) | 2014-05-28 | 2014-05-28 | Current detection circuit in a kind of electronic type voltage transformer |
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| CN201420280685.5U CN203929849U (en) | 2014-05-28 | 2014-05-28 | Current detection circuit in a kind of electronic type voltage transformer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104034938A (en) * | 2014-05-28 | 2014-09-10 | 杭州电子科技大学 | Current detection circuit in electronic voltage transformer |
| CN114113747A (en) * | 2021-11-19 | 2022-03-01 | 云南电网有限责任公司电力科学研究院 | Direct current transient state step standard device of TMR sensor |
| CN114113747B (en) * | 2021-11-19 | 2024-04-09 | 云南电网有限责任公司电力科学研究院 | Direct current transient step standard of TMR sensor |
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2014
- 2014-05-28 CN CN201420280685.5U patent/CN203929849U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104034938A (en) * | 2014-05-28 | 2014-09-10 | 杭州电子科技大学 | Current detection circuit in electronic voltage transformer |
| CN104034938B (en) * | 2014-05-28 | 2017-02-08 | 杭州电子科技大学 | Current detection circuit in electronic voltage transformer |
| CN114113747A (en) * | 2021-11-19 | 2022-03-01 | 云南电网有限责任公司电力科学研究院 | Direct current transient state step standard device of TMR sensor |
| CN114113747B (en) * | 2021-11-19 | 2024-04-09 | 云南电网有限责任公司电力科学研究院 | Direct current transient step standard of TMR sensor |
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