CN2298617Y - Ore-smelting electric furnace low-frequency power supply complete apparatus - Google Patents
Ore-smelting electric furnace low-frequency power supply complete apparatus Download PDFInfo
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- CN2298617Y CN2298617Y CN 97208317 CN97208317U CN2298617Y CN 2298617 Y CN2298617 Y CN 2298617Y CN 97208317 CN97208317 CN 97208317 CN 97208317 U CN97208317 U CN 97208317U CN 2298617 Y CN2298617 Y CN 2298617Y
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Abstract
The utility model relates to a low frequency electric supplying unitized device for ore heating furnaces. The utility model comprises power supply wires, a power supply control cabinet, a transformer, a short net, a self-baking electrode, an ore heating furnace body and an electrode lifting control cabinet. In the utility model, the secondary side of an electric furnace transformer is added with a set of frequency converter, and the output frequency and the voltage waveform of the output current of the frequency converter are controlled by a triggering pulse. The utility model can implement exact and reliable control according to different situations and different loads, and electric energy generated by the frequency changer can be directly used for the electrode for generating electric arcs, heat energy and implementing smelting. The connecting method of a three phase bridge type current transformer is also an in-phase antiparallel connecting method, and the interference of a magnetic field on the control circuit and the device is reduced.
Description
The utility model relates to the hot stove low frequency power supply of employed energy source device, particularly ore deposit device on the hot stove in a kind of ore deposit.
Existing ferro-alloy furnace adopts the power frequency supply supply power mode, all exists not enoughly on electrical property and technology, and big as the short net system impedance of big electric current, reactive loss is big, power factor is low, makes the active power reduction in the input stove, and therefore, energy consumption height, efficient are low.Since the arc furnace of power frequency three-phase alternating current, the electric arc shakiness, and the amplitude of the absolute value variable quantity of reactive power is big, causes voltage flicker to increase, and is therefore big to the electrical network surge impact, often causes public hazards to electrical network.In the fusion process, molten iron is poor in the stove internal mobility, and the cold and hot district difference of formation is bigger, difficult quality guarantee.The refractory consumption rate height, noise is big, and because the kelvin effect of power frequency power supply, the self-baking electrode sintering is successively slowed down by top layer to core, and sintering is inhomogeneous, and therefore of poor quality, the electrode paste consumption is big.
The purpose of this utility model is to overcome the shortcoming that exists in the above-mentioned prior art, provide a kind of consume energy low, efficient is high, arc stability, ore deposit hot stove low frequency power supply device that voltage flicker is little.
Technical solution of the present utility model is: ore deposit hot stove low frequency power supply the complete sets of equipment, comprise power line (1), electrical power control cabinet (2), transformer (3), short net (10), self-baking electrode (12), the hot body of heater in ore deposit (11), rise fall of electrodes control cubicle (9), the secondary output of transformer (3) connects bus (6) through low pressure and connects with frequency converter (7), frequency converter (7) output connects with self-baking electrode (12) by short net (10), and trigger impulse control cubicle (8) output and frequency converter (7) connect.
Described trigger impulse control cubicle (8) is by main frame (81), single-chip microcomputer (82), counter (83), just/negative group change over switch (84), voltage zero-crossing detection circuit (87), interrupt requests circuit (88) is formed, interrupt requests circuit (88) output connects with the input control end of main frame (81), main frame (81) output is connected with single-chip microcomputer (82) I/O mouth input, single-chip microcomputer (82) is connected through the input of data/address bus with counter (83), the output of single-chip microcomputer (82) by counter controls through just/negative group change over switch (84), pulse power amplifier circuit (85), photoelectrical coupler (86) is connected with the trigger end of frequency converter (7), voltage zero-crossing detection circuit (87) input connects frequency converter (7), a certain line voltage of its output electrical network synchronizing signal U
tConnect single-chip microcomputer (82).
The utility model installs a cover frequency converter additional at the furnace transformer secondary side, its output frequency and output current voltage waveform are controlled by trigger impulse, and according to different occasions, different loads, implement accurate, control reliably, the electric energy of frequency converter output is directly used in electrode and produces electric arc, produce heat energy, implement to smelt, the three-phase bridge current transformer is the connecting mode of cophase counter parallel connection, can reduce the interference of magnetic field to control circuit and equipment.The utility model is that the arc furnace of the energy carries out ferroalloy smelting with low frequency three-phase alternating current device, compare with prior art and to have following advantage: 1. reduce energy resource consumption: because the power supply of the power supply of low frequency three-phase alternating current, short net reactance value is descended, can improve power factor, reduce non-power consumption loss, increase active power, this low frequency smelting technique obvious energy conservation, and can improve output.2. voltage flicker is little: the self-baking electrode arc stability, flicker reduces, and can not cause public hazards to electrical network.3. noise is low, and comparable power frequency is smelted and reduced noise 5-10dB.4. reduce electrode paste material consumption: the low frequency power supply of electrical energy is smelted, and the kelvin effect in the lead reduces, so self-baking electrode barbecue temperature is even, top layer and nexine sintering have a narrow range of temperature, and have improved the self-baking electrode quality, and the electrode paste consumption is reduced.5. reduction refractory consumption rate: the utility model arc stability, reduce the temperature difference in cold and hot district, refractory material is heated evenly, and reduces local overheating, has prolonged the useful life of refractory material.6. owing to frequency reduces, reduced reactance, active power increases in the stove, and electrode stable work in the best is inserted deeply improves molten iron temperature, and because low frequency three-phase alternating current stirring action, bottom temperature significantly improves, and can not produce furnace bottom rising.
Describe the utility model embodiment in detail below in conjunction with accompanying drawing.
Fig. 1 is the utility model theory diagram.
Fig. 2 is the converter circuit schematic diagram.
Fig. 3 is a trigger impulse control cubicle theory diagram.
Fig. 4 is the interrupt requests circuit connection diagram.
Fig. 5 is the zero cross detection circuit connection layout.
Fig. 6 is the computer control connection layout.
Fig. 7 is the pulse power amplifier circuit connection layout.
Fig. 8 is the photoelectrical coupler connection layout.
Fig. 9 finds the solution the flow chart of delay angles alpha for computer control.
Ore deposit hot stove low frequency power supply the complete sets of equipment; as shown in Figure 1; electrical power control cabinet 2 inputs and power line 1 connect; electrical power control cabinet 2 outputs connect with furnace transformer 3 first polar curve circles; the secondary output of transformer 3 connects bus 6 through low pressure and connects with frequency converter 7; the output of frequency converter 7 and short net 10 connect; the self-baking electrode 12 of short net 10 produces electric arc and directly implements to smelt in body of heater; low-voltage variation and metering cabinet 4; low-voltage-powered control cubicle 5 connects with the low pressure output bus of transformer 3 respectively; in order to the power device of protection metering low-pressure side, low-voltage-powered cabinet 5 is the supply unit of electric furnace accessory machinery.Rise fall of electrodes control cubicle 9 connects with low-voltage-powered cabinet 5, and rise fall of electrodes control cubicle 9 is directly controlled the automatic lifting of self-baking electrode 12.Four groups of power supplys of transformer 3 outputs are connected with frequency converter 7, and frequency converter 7 is made up of six groups of three-phase bridge current transformer I-VI, and current transformer adopts the bridge-type all controlled rectifier circuit in the total system.Wherein I, III, V group current transformer share one group of power supply, and II, IV, VI group current transformer share another group power supply.Three electrode A of self-baking electrode 12, B, C are connected with six groups of bridge-type current transformers, electrode A is connected with current transformer I, II anode, be connected with current transformer IV, V negative terminal, electrode B is connected with rectifier III, IV anode, be connected with current transformer I, VI negative terminal, electrode C is connected with current transformer V, VI anode, is connected with current transformer II, III negative terminal.Flowing through the positive half cycle of electric current that A extremely goes up is the superposition of I group electric current and II group electric current, negative half period is the superposition of IV group and V group electric current, in like manner, the positive half cycle of the electric current that B extremely goes up is the superposition of III group and IV group electric current, negative half period is the superposition of I group and VI group, the positive half cycle of the electric current that C extremely goes up is the superposition of V group and VI group electric current, and negative half period is the superposition of II group and III group.Six groups of current transformers move according to I II-II III-III IV-IV V-V VI-VI I mode, and the method that changes output frequency makes each group operation switching accelerate exactly, and promptly the I II-II III-III IV-IV V-V VI-VI I cycle of operation reduces, and frequency is just accelerated.It is big current system that iron alloy electric furnace is smelted its short net, magnetic field is very strong, control circuit and miscellaneous equipment are produced interference, for weakening the influence in magnetic field, every group of current transformer of I～VI by the cophase counter parallel connection connecting mode just, negative 2 group's current transformers are formed, just, negative 2 group's power phases differ 180 °, current transformer I1 and I2 form inverse parallel and work simultaneously, the current direction of its dc bus is opposite, cancel out each other in magnetic field, two groups of power phases differ 180 °, and group I1 and I2 always have two thyristors of conducting simultaneously, the magnetic field that has produced when so also just having offset element conductive, thus whole device is reduced greatly owing to flowing through the magnetic field that big electric current produces.The promptly short net 10 of the output bus of frequency converter 7 is the short net of novel energy-conserving, and this weak point net electric conductor is a copper-steel composite material, and hollow rectangle, perfect conductor are water cooling mode.The output copper bar of short net 10 is the connected mode of cophase counter parallel connection, output copper bar connecting flexible cable, be serially connected in again on self-baking electrode 12 brasses, brasses and electrode are combined closely, conducting is on three electrodes respectively by A, B, C phase sequence to make the big electric current of three phase low frequency rate, and producing electric arc provides heat energy to carry out ferroalloy smelting.Electrode 12 is the composite material brasses, and A, B, C three-phase are directly gone into electrode, compares with old-fashioned contact tube conductor, and is simple in structure, good rigidly, and intensity is big, and the current density height is reliable, and resistance is little, and the life-span is long.Trigger impulse control cubicle 8 is by main frame 81, single-chip microcomputer 82, counter 83, just/negative group change over switch 84, voltage zero-crossing detection circuit 87, interrupt requests circuit 88 is formed, interrupt requests circuit 88 outputs connect with the input control end of main frame 81, main frame 81 outputs are connected with the I/O mouth input of single-chip microcomputer 82, single-chip microcomputer 82 is connected through the input of data/address bus with counter 83, the output of single-chip microcomputer 82 by counter controls through just/negative group change over switch 84, pulse effect circuit 85, photoelectrical coupler 86 is connected with the trigger end of frequency converter 7, voltage zero-crossing detection circuit 87 inputs connect frequency converter 7, a certain line voltage of its output electrical network synchronizing signal U
tConnect single-chip microcomputer 82.Main frame 81 adopts PC type microcomputer, and its CPU is INTEL8086, adopts assembler language to control and computing.The major function of main frame is according to the frequency and the amplitude of the required voltage of keying in, and produces delay angles alpha according to certain rules, after externally interrupt request singal INT arrives, makes an immediate response and the α word is sent into the I/O mouth of single-chip microcomputer 82.Main frame produces three different α words simultaneously, so that the three-phase output voltage symmetry.Single-chip microcomputer 82 and programmable counter 83 constitute pulse forming unit.Counter 8253-5 contains three 16 digit counters.Single-chip microcomputer 8749 receive from voltage zero-crossing detection circuit 87 with the synchronous signal U of a certain line voltage of electrical network
t, counter can produce six double frequency pulses synchronous with grid line voltage, and it produces the natural commutation point of corresponding thyristor, i.e. α=0 place constantly.Single-chip microcomputer 8749 reads in the α word by No. 1 I/O mouth, and process is to after its judgement, the computing, with the α count value N that draws
αBy data/address bus DB
0-7Deliver to 2 of 8253-5
#Counter.No. 2 I/O mouths of single-chip microcomputer are only used six roots of sensation line P2 wherein as the control port of frequency converter work
0-5The trigger impulse of six thyristors of difference control of conversion device.At six roots of sensation line P2
0-5In, have only two to be low level, the corresponding thyristor that triggers at every turn.The order of getting two lines of low level is: P2
0-1, P2
1-2, P2
2-3, P2
3-4, P2
4-5, P2
5-0, can clocklike trigger like this.2
#The output OUT2 of counter
#Clock signal as d type flip flop LS374.Work as N
αCount down to OUT2
#Produce a positive pulse, then the output PC of d type flip flop
1-6State and its input P2
0-5State consistency, produce the trigger impulse of thyristor again through pulse formation and power amplifier.P2
6Control just/conversion of negative group current transformer.Just/effect of negative group change over switch 84 is pulse to be sent to one group of thyristor (just organizing or negative group).The α word that main frame is sent is made of eight bit, wherein highest order be just/flag bit of negative group current transformer.0 expression should just trigger to be organized, and 1 expression should trigger negative group.Single-chip microcomputer 83 removes the control transformation switch by the value that detects this just.Voltage zero-crossing detection circuit 87 is made of zero-voltage-switch integrated circuit CA3059 and part discrete component.CA3059 does not need to establish in addition working power, and it directly obtains working power from tested voltage.It is input as three-phase line voltage, is output as pulse synchronous with a certain line voltage zero-cross point and through isolating.As shown in Figure 5, its output is at U
CbU greater than zero time
AbZero crossing produces a positive pulse.Interrupt requests circuit 88 is the control of carrying out other effective time and the computings in order to make full use of main frame.Main frame produces α according to certain rule, through some logic determines, at last the I/O mouth is delivered in the α word.To the three-phase AC-AC frequency converter, the time of sending three α words like this is not more than 1ms.Single-chip microcomputer is to read in the α word in the moment that negative pulse occurs at every turn.Utilize this of circuit generation and single-chip microcomputer can read in the α word constantly with frequently, slightly leading in time external interrupt request signal INT.Main frame makes an immediate response after receiving the INT signal, carries out interrupt service routine, produces the α word, and outputs to single-chip microcomputer by the I/O mouth, and single-chip microcomputer just in time can read in the α word this moment.Like this, main frame takies about 1ms and is used for and microcontroller communication in every 3.33ms, and all the other times can be used for other purpose control and computing.The interrupt requests circuit 88 that is provided with for generation INT signal is made of phase-locked loop C4046, counter C4040 and gate circuit.Input signal U
tBehind phase-locked loop and counter, produce the lock-out pulse of 20 quadruples, again through the suitable frequency division of counter and utilize " zero clearing " end of counter to control, can produce the INT signal.The different frequency multiplication of suitable selection is frequency dividing ratio when, can obtain out of phase and frequency and U
tSynchronous output pulse.Pulse power amplifier circuit 85 is with 2 of 8253-5
#The pulse signal of counter utilizes photoelectrical coupler 86 to carry out the electricity isolation, amplifies and removes to trigger thyristor.Pulse power amplifier circuit 85 is the input of each photoelectrical coupler in the corresponding GATE of each diode loop in the diode array wherein.
Single-phase ac-ac frequency converter comprises two groups of current transformers, and just organizing is P group current transformer, and negative group is N group current transformer.The basic control method of ac-ac frequency converter is continuously the trigger angle α of every group of current transformer of modulation, makes two groups of current transformers at separately output equal sinusoidal output voltage be arranged.When moving under no circulation situation, every group of current transformer forms a voltage waveform at its output, and only just allows conducting in each group current transformer is undertaken half cycle of load current.Be at current transformer during half cycle of idling,, blocked fully and should organize current transformer by suitable control to trigger angle α.Have only one group of current transformer conducting so at any one time, acyclic stream passes through between two current transformers.Owing to have cosine relation between trigger angle α and the reference voltage, therefore can carry out " cosine wave is handed over and cut " control, to produce the waveform corresponding with reference voltage to frequency converter.Cosine wave hands over a section control method to have the advantage that the output voltage distortion factor is low and harmonic content is few, but modeling scheme is difficult to realize.Utilize computer to ask for cosine wave and its reference voltage ripple and hand over to cut and constantly obtain numerous α value, then need separate trigonometric equation, and may be many-valued for separating of trigonometric equation, as seen such scheme also has problems.The computer control scheme of this device is to hand over cosine wave to cut the control method as standard, adopt improved sampling method (IPSM) to remove approximate trigonometric equation with linear equation, again separating of linear equation revised, tried to achieve as requested required a plurality of α values of different frequency with this.Cosine wave hand over to cut flow chart that the control method finds the solution delay angles alpha as shown in Figure 9.For separating of trigonometric equation gained may be many-valued.Gained separate selected initial value when depending on iteration, in order to obtain required " true solution ", choose two initial value π/3 and 2 π/3 in this program and carry out iteration, separating of gained judged, can obtain whole true solutions.Be provided with two signs in the program: α angular zone sign CON and positive and negative group of current transformer sign SIGN.Implication is as follows:
CON=0 represents 60 °≤α≤120 °
CON=1 represents 0 °≤α≤60 °
SIGN=0 represents the delay angle of corresponding negative group current transformer
SIGN=1 represents the corresponding delay angle of just organizing current transformer
The implication of each symbol is as follows in the program:
s
iBe the iteration initial value
t
iThe moment of corresponding I α value
SA (I) is for depositing t
iArray
M is output voltage maximum commutation number of times in a cycle
RP: as 0 °≤ω t
iIn the time of≤60 °, pulse should be delivered to and just organize current transformer
RN: as 0 °≤ω t
iIn the time of≤60 °, pulse should be delivered to negative group current transformer
LRP: as 60 °≤ω t
iIn the time of≤120 °, pulse should be delivered to and just organize current transformer
LRN: as 60 °≤ω t
iIn the time of≤120 °, pulse should be delivered to negative group current transformer
By this program, after revising according to linearisation, the α value of numerous ti correspondences of trying to achieve is delivered to pulse each thyristor of positive and negative group of current transformer again.The operation of main frame is also fairly simple in the control of using this programme, initial value I=0 at first is set, after main frame responds interrupt request singal for the first time, can obtain first through computing, judgement triggers constantly, through revising and can converting corresponding delay angles alpha numerical value to, by the output of I/O mouth, again with I+1, for next break in service is prepared ...Along with the difference of I, after I=m executes, I is changed to 0 again, so move in circles.Be output as the process that example illustrates flow chart with * RP input, * RN, iteration be set earlier in the main frame initially put s
i=60 °, computer is calculated the moment t of the 1st corresponding α value
i, judge 0 °≤ω t through main frame
i≤ 60 °, if in this scope, output signal to * LRP, if not at this 0 °≤ω t
iThen whether verify in≤60 ° of scopes at 60 °≤ω t
iIn≤120 ° of scopes, if, then signal is delivered to and just organized current transformer and constantly export next α numerical value, if not then being set in addition, iteration initially puts s
i=120 °, computer is calculated the moment t of the 1st corresponding α value
iIf, at 60 °≤ω t
iIn≤120 ° of scopes, then deliver to and just organizing current transformer and constantly exporting a α numerical value, if not, then send anti-group of current transformer * RN.This programme is by simple calculations, can determine all delay angles alpha in a cycle of output voltage, harmonic component in output voltage and distortion factor are obviously reduced, this controlling schemes not only output voltage frequency adjustable arbitrarily in interior scope (frequency selects to select for use as far as possible the 1/3 octave component rate of supply frequency at 0.05～12.5HZ, as 50/3,50/6,50/90 ... Deng) can also make output voltage amplitude (power) adjustable arbitrarily, this controlling schemes gained output voltage waveforms is handed near desirable cosine wave and is cut the waveform that the control method is obtained, the operation expression of this controlling schemes is a linear representation, therefore is easy to the real-time operation of computer.
Claims (3)
1. the hot stove low frequency power supply in ore deposit the complete sets of equipment, comprise power line (1), electrical power control cabinet (2), transformer (3), short net (10), self-baking electrode (12), the hot body of heater in ore deposit (11), rise fall of electrodes control cubicle (9), it is characterized in that: the secondary output of transformer (3) connects bus (6) through low pressure and connects with frequency converter (7), frequency converter (7) output connects with self-baking electrode (12) by short net (10), and trigger impulse control cubicle (8) output and frequency converter (7) connect.
2. ore deposit as claimed in claim 1 hot stove low frequency power supply the complete sets of equipment, it is characterized in that: described trigger impulse control cubicle (8) is by main frame (81), single-chip microcomputer (82), counter (83), just/negative group change over switch (84), voltage zero-crossing detection circuit (87), interrupt requests circuit (88) is formed, interrupt requests circuit (88) output connects with the input control end of main frame (81), main frame (81) output is connected with single-chip microcomputer (82) I/O mouth input, single-chip microcomputer (82) is connected through the input of data/address bus with counter (83), the output of single-chip microcomputer (82) by counter (83) control through just/negative group change over switch (84), pulse power amplifier circuit (85), photoelectrical coupler (86) is connected with the trigger end of frequency converter (7), voltage zero-crossing detection circuit (87) input connects frequency converter (7), a certain line voltage of its output electrical network synchronizing signal U
tConnect single-chip microcomputer (82).
3. ore deposit as claimed in claim 2 hot stove low frequency power supply the complete sets of equipment is characterized in that: the flow process that current transformer thyristor trigger angle α is found the solution in described computer control is as follows:
Put initial value: I=0 CON=0 SIGN=1
After main frame responds interrupt request singal for the first time, obtain first through computing, judgement and trigger t constantly
i, through revising and convert to corresponding delay angles alpha numerical value, by the output of I/O mouth, again with I+1, for next break in service is prepared ..., along with the difference of I, after I=m executes, I is changed to 0 again, so move in circles,
α angular zone sign CON and positive and negative group of current transformer sign SIGN wherein are set, and implication is as follows:
CON=0 represents 60 °≤α≤120 °,
SIGN=1 represents the delay angle of corresponding negative group current transformer,
M is output voltage maximum commutation number of times in a cycle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97208317 CN2298617Y (en) | 1997-02-14 | 1997-02-14 | Ore-smelting electric furnace low-frequency power supply complete apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97208317 CN2298617Y (en) | 1997-02-14 | 1997-02-14 | Ore-smelting electric furnace low-frequency power supply complete apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2298617Y true CN2298617Y (en) | 1998-11-25 |
Family
ID=33927787
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 97208317 Expired - Fee Related CN2298617Y (en) | 1997-02-14 | 1997-02-14 | Ore-smelting electric furnace low-frequency power supply complete apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2298617Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101228811B (en) * | 2005-08-02 | 2011-08-10 | 西门子公司 | Voltage transformer system for electric arc furnace with three electrodes |
| CN105716416A (en) * | 2014-12-03 | 2016-06-29 | 冯志权 | Variable-frequency electric arc furnace |
| CN110094965A (en) * | 2018-02-11 | 2019-08-06 | 于文 | Novel DC electric furnace |
-
1997
- 1997-02-14 CN CN 97208317 patent/CN2298617Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101228811B (en) * | 2005-08-02 | 2011-08-10 | 西门子公司 | Voltage transformer system for electric arc furnace with three electrodes |
| CN105716416A (en) * | 2014-12-03 | 2016-06-29 | 冯志权 | Variable-frequency electric arc furnace |
| CN105716416B (en) * | 2014-12-03 | 2018-09-18 | 冯志权 | A kind of frequency conversion type electric arc furnaces |
| CN110094965A (en) * | 2018-02-11 | 2019-08-06 | 于文 | Novel DC electric furnace |
| CN110094965B (en) * | 2018-02-11 | 2024-04-02 | 于文 | Novel direct-current smelting electric furnace |
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|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |