CN1080057A - Electric arc detecting device - Google Patents
Electric arc detecting device Download PDFInfo
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- CN1080057A CN1080057A CN 92104642 CN92104642A CN1080057A CN 1080057 A CN1080057 A CN 1080057A CN 92104642 CN92104642 CN 92104642 CN 92104642 A CN92104642 A CN 92104642A CN 1080057 A CN1080057 A CN 1080057A
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- Prior art keywords
- arc
- operational amplifier
- voltage
- output
- detecting device
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Abstract
A kind of electric arc detecting device, the output of its arc flow sensor is joined with arc stream, arc voltage curve simulator respectively through amplifier rectifier, the output of arc voltage signal generator and arc voltage curve simulator join, and the output of arc stream, arc voltage curve simulator is joined through differential operational amplifier and phase inverter.The invention solves the inaccurate problem of arc-detection in the prior art, provide a kind of highly sensitive, reaction velocity is fast, measuring-signal is accurate, the electric arc detecting device of good stability.
Description
The present invention relates to a kind of electric arc detecting device, can be used for control of discharging gap in the automatic control of the automatic conditioning equipment of electric-arc furnace steelmaking, reversible AC frequency modulation arrangements for speed regulation, reversible dc arrangements for speed regulation, hydraulic pressure electric arc furnaces and the spark erosion equipment or the like.
At present, it is certain with the ratio of pilot arc voltage and flame current mostly the automatic regulator that electric-arc furnace steelmaking equipment is adopted is, and carry out work according to the method for differential adjusting, and there are the following problems for it:
1, the arc voltage value is inaccurate.Because what the taking-up of arc voltage was adopted is voltage transformer (VT), the voltage transformer (VT) primary side can not really be connected on the electric arc two ends, but is connected on the bus row of furnace transformer secondary side, like this, the arc voltage of measuring can only be an approximate value, which comprises at least electrode in interior short net pressure drop.Because specified arc stream can reach the training of 1 Wan An usually when smelting, although short net resistance is very little, when so big electric current flow through short net, the voltage drop on it also was considerable.
2, detection signal is inaccurate when flame current increases greatly.In the electric arc steelmaking process, along with the increase of flame current, because heating, the ionizing event of arc column increases, and the conductivity of arc column obviously increases, and the needed voltage of pilot arc has just reduced.When flame current increases greatly, it is very slow that the increase of arc column conductivity becomes, at this moment, the electric arc equivalent resistance is with reducing that current values is inversely proportional to, and arc voltage remains unchanged basically, its family curve is smooth, and this has just destroyed the certain of arc voltage and flame current ratio, makes detection signal inaccurate.
3, furnace bottom resistance has reduced the working sensitivity and the rapidity of automatic electrode regulator.Three-phawse arc furnace steel-making, in order to guarantee the operate as normal of automatic regulator, must make the voltage drop on the voltage measurement circuit equal arc voltage, but when a phase current interruption or a phase short circuit, the furnace bottom current waveform is similar to sine wave, if the resistance of furnace bottom is not equal to zero, then under the state of scratching, because the furnace bottom current rush, the change in voltage that regulator voltage is measured on the loop changes non-linear proportionate relationship with arc voltage.It is basis
U＝U
a-r
oI
o
Wherein, the U-arc voltage is measured the voltage at two ends, loop;
The Ua-phase voltage;
r
o-furnace bottom resistance;
I
O-furnace bottom electric current.
During single-phase current interruption, the voltage drop on the voltage measurement circuit less than electrode with the voltage between the stove molten bath; And when working as single-phase short circuit or approaching short circuit, the voltage drop on the voltage measurement circuit is greater than arc voltage.Because of the speed of action of regulator depends on the size of control signal, as seen, because r
oI
oInfluence, furnace bottom resistance has reduced the working sensitivity and the rapidity of automatic electrode regulator.
At the automatic conditioning equipment of electric-arc furnace steelmaking, reversible AC frequency modulation arrangements for speed regulation, control of discharging gap or the like field in the automatic control of reversible dc arrangements for speed regulation, hydraulic pressure electric arc furnaces and the spark erosion equipment, because arc-detection is inaccurate, its control or degree of regulation are all inaccurate.
The objective of the invention is to avoid above-mentioned weak point of the prior art, and provide that a kind of measuring-signal is accurate, highly sensitive, reaction velocity is fast, good stability, the electric arc detecting device that can avoid short circuit that electrical network is impacted.
Purpose of the present invention can reach by following measure:
A kind of electric arc detecting device, comprise the arc flow sensor 1 that constitutes by current transformer LHQ and pull-up resistor R1, its special character is: the output of described arc flow sensor 1 is through amplifier rectifier 2 one tunnel input arc stream curve simulators 4, arc voltage curve simulator 5 is imported with the output of arc voltage signal generator 3 in another road, described arc stream curve simulator 4 is transported to differential operational amplifier 6 with the output of arc voltage curve simulator 5, and the output of described differential operational amplifier 6 is joined with phase inverter 7 and phase inverter 8 respectively.
Amplifier rectifier 2 of the present invention comprises rp-op amp A1, the A2 of serial connection mutually, and its output is joined through commutation diode D1, D2 and filter capacitor C1.
Arc voltage signal generator 3 of the present invention comprises rp-op amp A7, and its inverting input and potentiometer R24 join, and potentiometer R23 is connected in series mutually with potentiometer R24.
Arc stream curve simulator 4 of the present invention can be made of operational amplifier A 3, described arc voltage curve simulator 5 is made of operational amplifier A 4, described differential operational amplifier is made of operational amplifier A 5, described phase inverter 7 is made of operational amplifier A 6, and described phase inverter 8 is made of operational amplifier A 8.
Accompanying drawing drawing of the present invention is described as follows:
Fig. 1 is a theory diagram of the present invention;
Fig. 2 is the circuit theory diagrams of the embodiment of the invention.
The invention will be further described below in conjunction with accompanying drawing;
Referring to Fig. 1, arc flow sensor 1 is used to detect the electric current of electric arc, its output is behind amplifier rectifier 2, one tunnel input arc stream curve simulator 4, arc voltage curve simulator 5 is imported with the output of arc voltage signal generator 3 in another road, arc stream curve simulator 4 is transported to differential operational amplifier 6 simultaneously with the output voltage of arc voltage curve simulator 5, and the output voltage of differential operational amplifier 6 carries out anti-phase respectively through phase inverter 7 and phase inverter 8, to obtain required polar voltages.
Referring to Fig. 2, arc flow sensor 1 comprises current transformer LHQ and pull-up resistor R1, current transformer LHQ is a big mutual inductor that changes, if the present invention is applied on the electrical arc furnace automatic regulator, suppose that this electric arc furnaces working point is chosen to be 9000 peaces, then the current transformer secondary current should be 3 peaces, and the voltage drop on resistance R 1 at this moment should be 3 volts.Amplifier rectifier 2 is by rp-op amp A1～A2, commutation diode D1～D2, filter capacitor C1 and resistance R 2～R7 constitute, AC signal voltage on the pull-up resistor R1 amplifies through operational amplifier A 1, A2, again through commutation diode D1, D2 full-wave rectification, through capacitor C 1 filtering, on rectification load resistance R 7, obtain a direct current voltage U
R7, suitably select output resistance R3, the R6 of operational amplifier A 1, A2, and match suitable capacitor C 1 and resistance R 7, make voltage U
R7Equal voltage U on the resistance R 1
R1Two times, and make voltage U
R7The same voltage U of variation
R1Be changed to linear relationship.Voltage U
R7Transport to arc stream curve simulator 4 and arc voltage curve simulator 5 simultaneously.Arc stream curve simulator 4 is made of operational amplifier A 3 and resistance R 8～R11, operational amplifier A 3 is homophase input operational amplifiers that an enlargement factor equals 1, resistance R 8 equates with the resistance of resistance R 10, the output voltage of operational amplifier A 3 has reflected the situation of change of arc stream truly, and operational amplifier A 3 also plays impedance conversion and buffer action at this.Arc voltage curve simulator 5 has two input signals, and one is the arc-stream voltage signal from amplifier rectifier 2, and another road is the simulation arc voltage signal from arc voltage signal generator 3.Arc voltage signal generator 3 is made of potentiometer R23～R24, resistance R 25～R27 and rp-op amp A7.When potentiometer R24 placed the maximum end of resistance, regulator potentiometer R23 can simulate the distribution of steel-making different times, and according to the converter of different tonnages, different work arc streams, regulator potentiometer R23 can make under the different work arc stream states can both reach balance.Potentiometer R24 is an arc stream rectification potentiometer, and according to different smelting periods, regulator potentiometer R24 all can realize the selection to different operating point.Rp-op amp A7 can realize the voltage needs of opposed polarity, also can be used as the input interface of microcomputer, is used as anti-phase input summer usefulness, and it plays impedance conversion and buffer action too.Do not having microcomputer when input, rp-op amp A7 is only as phase inverter usefulness, output negative pole voltage.Arc voltage curve simulator 5 is made of reverse input summer A4 and resistance R 12～R15.If the electric arc furnaces distribution is selected, the electric furnace electric current is adjusted on demand, and so, arc voltage signal generator 3 is output as a negative dc voltage, the inverting input 13 that it transports to reverse input summer A4 through output terminal 14 and the resistance R 27 of rp-op amp A7; Transport to the inverting input 13 of totalizer A4 through resistance R 7 and R12 by the arc stream signal of amplifier rectifier 2 outputs.Principle by reverse input summer can get:
U
A4＝-〔（R15/R12）U
R12+（R15/R13）U
R13〕……（1）
Wherein, U
A4The output voltage of-arc voltage curve simulator 5;
U
R12The output voltage of-amplifier rectifier 2;
U
R13The output voltage of-arc voltage signal generator 3;
When R12=R13=R15,
U
A4＝（U
R12+U
R13）……（2）
Adjust potentiometer R23, R24, make the output voltage U of rp-op amp A7
R13Be a fixing reverse voltage under a certain particular job state, for example, electric arc furnaces melting stage distribution voltage be 127 volts, the arc stream working point is selected in 9000 amperes, at this moment, arc voltage signal generator 3 is exported-12 volts of voltages, by (2) formula as can be seen because U
R13Be fixing-12 volts of voltages, the output voltage U of arc voltage curve simulator 5
A4The voltage U that depends on amplifier rectifier 2 outputs fully
R12Variation, promptly along with the increase of flame current, the output voltage of arc voltage curve simulator 5 will be from+12 volts of linear minimizings, this curve is desirable arc voltage change curve.Because this arc voltage curve is not subjected to any factor affecting except that arc stream, and be the function of arc stream, so just eliminated disadvantage of the prior art.The output voltage of arc stream curve simulator 4 and arc voltage curve simulator 5 is transported to the input end of differential operational amplifier 6 simultaneously, differential operational amplifier 6 is made of operational amplifier A 5, capacitor C 2 and resistance R 16～R19, the output voltage of arc stream curve simulator 4 is delivered to the in-phase input end 3 of differential operational amplifier 6, and the output voltage of arc voltage curve simulator 5 is delivered to its inverting input 2.Anti-phase input and homophase input circuit all belong to single-ended input for the input of operational amplifier, when signal during simultaneously from the input of end of oppisite phase and in-phase end, be called the input of differential input or both-end, as shown in Figure 2, differential operational amplifier A5 is combined by homophase input operational amplifier and anti-phase input operational amplifier, but import for homophase, its input signal is not direct adding, but after resistance R 17 and R19 dividing potential drop, be added to in-phase input end 3, therefore, desirable input and the output relation of differential operational amplifier can be formed by the output superposition of above-mentioned two kinds of circuit.Differential operational amplifier A5 is two input pickup resistance symmetries, promptly during R17=R19=R18, and its output voltage U
A5=R18/R16(U
R16-U
R17), i.e. output voltage U
A5With input difference voltage (U
R16-U
R17) be directly proportional.When the magnitude of voltage of arc voltage curve simulator 5 output during greater than the output voltage of arc stream curve simulator 4, differential operational amplifier 6 is output as positive polarity voltage, when the voltage of arc voltage curve simulator 5 output during less than the output voltage of arc stream curve simulator 4, differential operational amplifier 6 output negative pole voltages: when two output voltages equate, the voltage of differential operational amplifier 6 outputs just is zero, at this moment, electric arc furnaces just is able to balance phase inverter 7 and is made of operational amplifier A 6 and resistance R 20～R22; Phase inverter 8 is made of operational amplifier A 8 and resistance R 28～R30.Phase inverter 7,8 mainly is to carry out the output of differential operational amplifier 6 anti-phase, can select needed polar voltages at the output terminal of operational amplifier A 6, A8 respectively as required, for example, in the automatic conditioning equipment of electric-arc furnace steelmaking, the output voltage of operational amplifier A 6, A8 can be used as control signal and goes respectively to control the silicon controlled conduction angle, realizes reversible variable voltage control; The output of phase inverter 7,8 also can be used as automatic control of reversible AC frequency modulation arrangements for speed regulation, reversible dc arrangements for speed regulation, hydraulic pressure and direct current electric arc furnace or the like, and it can control discharging gap etc. accurately in spark erosion equipment.Phase inverter 7,8 also plays impedance conversion and buffer action.
The present invention compared with prior art has following advantage:
Improve steel-making efficient, saved the energy; Greatly reduced the short circuit number of times, thereby reduced the carburetting of graphite electrode to molten steel, improved the quality of steel, measuring-signal is accurate; Highly sensitive, reaction speed is fast; Avoided the impact of short circuit to electrical network; Good stability; Improved work power supply environment.
Claims (4)
1, a kind of electric arc detecting device, comprise the arc flow sensor 1 that constitutes by current transformer LHQ and pull-up resistor R1, it is characterized in that: the output of described arc flow sensor 1 is through amplifier rectifier 2 one tunnel input arc stream curve simulators 4, arc voltage curve simulator 5 is imported with the output of arc voltage signal generator 3 in another road, described arc stream curve simulator 4 is transported to differential operational amplifier 6 with the output of arc voltage curve simulator 5, and the output of described differential operational amplifier 6 is joined with phase inverter 7 and phase inverter 8 respectively.
2, electric arc detecting device according to claim 1 is characterized in that: described amplifier rectifier 2 comprises rp-op amp A1, the A2 of serial connection mutually, and its output is joined through commutation diode D1, D2 and filter capacitor C1.
3, electric arc detecting device according to claim 1 and 2 is characterized in that: described arc voltage signal generator 3 comprises rp-op amp A7, and its inverting input and potentiometer R24 join, and potentiometer R23 is connected in series mutually with potentiometer R24.
4, electric arc detecting device according to claim 3, it is characterized in that: described arc stream curve simulator 4 is made of operational amplifier A 3, described arc voltage curve simulator 5 is made of operational amplifier A 4, described differential operational amplifier is made of operational amplifier A 5, described phase inverter 7 is made of operational amplifier A 6, and described phase inverter 8 is made of operational amplifier A 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92104642 CN1080057A (en) | 1992-06-11 | 1992-06-11 | Electric arc detecting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92104642 CN1080057A (en) | 1992-06-11 | 1992-06-11 | Electric arc detecting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1080057A true CN1080057A (en) | 1993-12-29 |
Family
ID=4940900
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 92104642 Pending CN1080057A (en) | 1992-06-11 | 1992-06-11 | Electric arc detecting device |
Country Status (1)
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|---|---|
| CN (1) | CN1080057A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102116787A (en) * | 2011-02-23 | 2011-07-06 | 河南科技大学 | Device for testing electric arc in high-speed electric sliding contact state |
| CN102183684A (en) * | 2010-01-15 | 2011-09-14 | 三星电子株式会社 | Arc discharge detecting circuit, light source driving apparatus and method of driving a light source using the same |
| CN103223549A (en) * | 2013-04-25 | 2013-07-31 | 北京灿烂阳光科技发展有限公司 | Detection device and method for arc voltage adjustment control system of plasma cutting machine |
-
1992
- 1992-06-11 CN CN 92104642 patent/CN1080057A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102183684A (en) * | 2010-01-15 | 2011-09-14 | 三星电子株式会社 | Arc discharge detecting circuit, light source driving apparatus and method of driving a light source using the same |
| CN102183684B (en) * | 2010-01-15 | 2015-08-12 | 三星显示有限公司 | The method of arc discharge testing circuit, apparatus of driving light source and driving light source |
| CN102116787A (en) * | 2011-02-23 | 2011-07-06 | 河南科技大学 | Device for testing electric arc in high-speed electric sliding contact state |
| CN103223549A (en) * | 2013-04-25 | 2013-07-31 | 北京灿烂阳光科技发展有限公司 | Detection device and method for arc voltage adjustment control system of plasma cutting machine |
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|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |