CN201239844Y - Novel soft switch inversion type carbon dioxide gas protecting welder - Google Patents

Abstract

The utility model introduces the advanced soft switch technology into the technical field of the welding. The soft switch technology is combined with the inversion technology, through the method of phase shift control and resonance switching, the power device of an arc welding inverter is powered on and powered off at zero voltage or zero current, so that the consumption of the power device can be reduced to zero, the efficiency is improved, the damage possibility of the power device is reduced, the electromagnetic interference and the radio-frequency interference are obviously reduced, the reliability of the product is enhanced, and the new generation of arc welding inverter becomes a novel product with environmental protection and energy conservation. The utility model mainly introduces a main power circuit and a power output circuit of the arc welding inverter, a speed adjusting circuit of an electrode feeding machine, an inching electrode feeding and welding torch switching circuit, a quenching circuit and a two-step/four-step sequence control circuit which are provided with self-locking function, and a unified circuit for welding parameter selection.

Description

A kind of novel soft-switching inversion formula carbon dioxide gas arc welding machine

The utility model is to introduce a kind of novel soft switch technique contravariant CO that has ₂Gas shielded welding machine, CO ₂Gas shielded arc welding be grow up phase early 1950s a kind of efficiently, solder technology cheaply.Its appearance causes gazing at of common people immediately, also is the solder technology that China gives priority to and promotes for these years.

CO ₂The gas shield solder technology has experienced by the SCR control formula to contravariant CO ₂Though the evolution of gas shielded arc welding is CO ₂Gas is protected inverter type welder and is had efficient, energy-conservation, province's material, light, many advantages such as good welding performance.But, present contravariant CO ₂The most hard switching circuit that adopt of gas shielded welding machine, switching loss is big, has reduced the efficient of circuit.Simultaneously, a large amount of higher hamonic waves, scurry, cause pollution electrical network to electrical network, electromagnetic interference (EMI) and the radio environment (RFI) a large amount of to aerial generation, simultaneously, CO ₂Gas shielded arc welding exists still that the spatter thing is many, appearance of weld is undesirable, and these all are to limit CO ₂The further development and the popularization of gas shield solder technology.

The purpose of this utility model is exactly: advanced person's soft switch technique is incorporated into welding technology field, combine with inversion transformation technique, the mode of switching by resonance turns on and off device for power switching under no-voltage or zero current, make the loss of power component reduce to zero, improved efficient, reduced the damage probability of power device, electromagnetic interference and Radio frequency interference significantly reduce, and have improved reliability of products.Therefore, the utilization of soft switch technique is CO ₂The development of gas shield inverter type welder has indicated the direction of advancing.

The purpose of this utility model is achieved like this:

The utility model has been used a kind of magnetizing inductance that adopts magnetic switch to enable optimization, cooperates leakage inductance and distributed inductance and corresponding external resonant inductance electric capacity simultaneously, realizes high-power soft switch CO ₂Gas keep alive weldering inverter is called phase shifting control full-bridge zero-voltage soft switch transducer.

Magnetizing inductance is the non-linear element that is controlled by exciting curent, the leakage inductance of high-frequency power transformer and magnetizing inductance all are the inductance elements that comprises in the arc welding inverter, can be by adjusting the magnetic core air gap simply, the magnetizing inductance value of transformer is carried out freely adjusting, cooperate corresponding external resonant inductance, electric capacity, make full use of these and optimize the resonant transformation that the magnetizing inductance that is provided with is realized the soft switch of full-bridge circuit.

The necessary and sufficient condition that magnetizing inductance participates in the change of current of full-bridge converter resonance is: the secondary side voltage of power transformer is non-vanishing during the change of current, and promptly power transformer is in energy output state or pure inductance state.

In this basic phase shifting control full bridge soft switch circuit, when the leading brachium pontis switching tube change of current, power transformer is in the energy output state, and magnetizing inductance has participated in the resonance commutation course of lead man.When sharp inductance value appropriately is provided with, can guarantee that lead man still can realize Zero-voltage soft switch when zero load.When the lagging leg change of current, power transformer is just being located passive states, promptly is in the afterflow state, and outputting inductance and magnetizing inductance all can not participate in the resonance change of current of lagging leg.This is the basic reason that lagging leg is difficult to realize ZVT, and improved basic principle is to make transformer be converted into the pure inductance state by the afterflow state, thereby enables the series resonance that magnetizing inductance participates in lagging leg.The simplest way adopts magnetic switch exactly, and so-called magnetic switch just is meant by weber number decision impedance, saturated nonlinear inductance when the convergence zero current.

Adopting magnetic switch, enable suitable magnetizing inductance, cooperate leakage inductance and corresponding external resonant inductance electric capacity simultaneously, realize the new-type circuit of Zero-voltage soft switch, is a kind of simple, reliable, economic and practical high-power soft switch DC converter topology.Solve arc welding inverter and hour can't realize the problem of the soft switch change of current at zero load and welding current.When maximum current in the magnetizing inductance is 1～5A, can guarantee leading brachium pontis and lagging leg in the phase-shifted full-bridge converter, no matter under any load, all reach Zero-voltage soft switch, duty-cycle loss is an insoluble problem in the phase shift zero-voltage soft switch full converter, adopt magnetic switch, enable the magnetizing inductance of optimization, not only in very wide loading range, realize Zero-voltage soft switch, and reduce the loss of primary side current greatly dutycycle.

Soft switch converting technique is a system engineering in the realization of arc welding inverter, relate to all many-sides, at this, mainly introduce the main circuit of arc welding inverter, power output circuit, the alignment circuit of wire-feed motor, crawl wire feed and arc welding gun switch circuit, receipts arc circuit and two steps/four steps sequence circuit with auto-lock function, the unified circuit that welding parameter is selected.

Accompanying drawing 1 is for functional-block diagram of the present utility model is: novel soft-switching inversion formula CO ₂Gas shielded welding machine is by electric power main circuit, power output circuit, and the alignment circuit of wire-feed motor, crawl wire feed and arc welding gun switch circuit, receipts arc circuit and two steps/four with auto-lock function go on foot sequence circuit, the compositions such as unified circuit that welding parameter is selected.

One, electric power main circuit

1, electric power main circuit

Its electric power main circuit of the soft-switching arc welding inverter of utility model adopts full-bridge type DC-DC main circuit, the design power of this arc welding inverter is 22KVA, reverse frequency is 30KHz, the switch power device is the IGBT pipe, the welding current 500A of output, the DC voltage 540V of input, the full-load voltage of output is 45V, the power transformer core material adopts Fe-based amorphous alloy METGLAS2605TCA, magnetic induction density B s 1.56T (or 15600Gs), a kind of novel magnetic material has high saturated magnetic strength, low-loss, low cost.

2, electric power main circuit parameter designing:

2.1 the selection of arc welding inverter power tube:

Power tube adopts the IGBT pipe, its advantage is to have the input impedance height, driving force is strong, switching speed is fast, no secondary goes out to wear etc., the IGBT pipe under high pressure still has the ability of very strong control electric current simultaneously, avoided the problem of multitube parallel generation as switching component with it, drive circuit adopts the highly integrated special chip EXB841 of IGBT, has used soft switch technique simultaneously, makes switching component realize the turn-on and turn-off of no-voltage, greatly reduce switching loss, improve the reliability of soft-switching inversion welding machine, improved efficient, saved the energy.The IGBT pipe is the desirable main flow switch power device of present arc welding inverter.

2.2 transformer first and second side no-load voltage ratio K is an important parameter in the arc welding inverter.

If under the full-load voltage, select the maximum conduction ratio Dsec=0.85 of secondary side, then Circuit Fault on Secondary Transformer voltage:

$V\sec =\frac{V_O+V_D+V_{\mathrm{Ri}}}{D\sec }=\frac{45+1.5+3}{0.85}$

$=58.2V$

In the formula: V ₀Be arc welding inverter full-load voltage, V _o=45V

V _DBe the on-state voltage drop of output commutation diode, V _D=1.5V

V _RiBe the pressure drop that the power supply dead resistance causes, V _Ri=3V

One of arc welding inverter, the secondary side transformation ratio should be calculated by minimum DC input voitage, and minimum DC input voitage, V _{In (min)}=540 * (1-20%)=424V

So transformer one, the calculated value of secondary side no-load voltage ratio k is:

$K=\frac{\mathrm{Vin}\left(\min \right)}{V\sec }=\frac{424}{58.2}=7.3$ Get K=7

2.3 determine the arc welding inverter transformer once, the turn ratio of secondary side.

Select the high workload magnetic flux density Bm=1.56T of magnetic core, then 1 umber of turn is:

${\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="Y200820052947E00201.png,Y200820052947E00211.png"\; state="\{\{state\}\}">N</figure-callout>}}_1=\frac{\mathrm{Ein}\&times;{10}^8}{4.4f0\mathrm{<figure-callout\; id="0"\; label="A"\; filenames="Y200820052947E00181.png,Y200820052947E00201.png"\; state="\{\{state\}\}">A</figure-callout>}0\mathrm{Bm}}=\frac{600\&times;10}{4.4\&times;30\&times;{10}^3\&times;1.56\&times;{10}^4\&times;2.64}$

$=11.04$

In the formula: E _InBe input direct voltage, E _In=600V

Fo is the operating frequency of arc welding inverter, fo=30KH _Z

Ao is effective magnetic core sectional area, Ao=2.64cm ²

Bm is an amorphous CD core material magnetic flux density, Bm=1.56T

Consider transformer one, the secondary side no-load voltage ratio is 7, and for the number of turn that guarantees the first side winding number of turn and secondary side winding all is an integer, so the secondary side winding number of turn gets 2, the first side winding number of turn is chosen as 14, and floating voltage is 60-90V.

2.4 the calculating of magnetic core gas length:

In the Novel Soft Switching arc welding inverter, magnetizing inductance has participated in the process of the soft switch of power switch pipe, flow in order to obtain the suitable magnetoelectricity of paying, under idle condition, also can realize the Zero-voltage soft switch change of current, need design paying the magnetic inductance value so that guarantee Arc Welding Power.

Magnetizing inductance is the structural parameters of power transformer magnetic core and first side winding, adopts the method that changes the magnetic core gas length, can make things convenient for, and neatly the magnetizing inductance amount is adjusted and is measured.

The magnetizing inductance value:

$\mathrm{Lm}=\frac{\mathrm{Vin}\left(\max \right)\mathrm{<figure-callout\; id="4"\; label="Tp"\; filenames="Y200820052947E00181.png,Y200820052947E00191.png"\; state="\{\{state\}\}">Tp</figure-callout>}}{4\mathrm{lm}\left(\max \right)}=\frac{600\&times;33.3\&times;{10}^{-6}}{4\&times;4.5}$

$=1.11\&times;{10}^{-3}H$

In the formula: V _{In (max)}Be the maximum of primary side DC input voitage, V _{In (max)}=600V

Tp is inversion period T p=33.3 μ S

I _{M (mix)}Be exciting curent peak value, V _{M (mix)}=4.5A

By aforementioned calculation, magnetizing inductance Lm, its inductance value is far longer than leakage inductance L _1k, thus, can ignore leakage inductance L _IkOn pressure drop, so expanded the soft-switching range of lagging leg greatly.

Increase a capacitance Cs in main circuit, it is to be formed in parallel by a plurality of polarity free capacitors, and it can increase overcurrent capability, can reduce the equivalent internal resistance (ESR) of power supply again, play every straight effect, can prevent transformer bias again, and realize the zero-current switching of lagging leg.Saturable reactor, i.e. magnetic switch L _S1, L _S2Be made up of around multiturn coil ferrite magnetic, when having electric current or its two ends voltagesecond product enough big, saturable reactor is saturated, and induction reactance is zero, when its withdraw from saturated after, induction reactance is very big, its effect is to prevent main circuit leakage inductance and C _SCause the reversing the current vibration, realize the zero current turning-on of lagging leg.

Above-mentioned to Novel Soft Switching resonance inverter CO ₂Each parameter of Arc Welding Power main circuit, by repeated calculation in theory, with repeatedly practising in the production, adopt magnetic switch to enable the magnetizing inductance of optimization, cooperate leakage inductance and distributed inductance simultaneously, realize this new-type circuit of Zero-voltage soft switch, solve arc welding inverter and hour can't realize the problem of the soft switch change of current at zero load and welding current, have unique advantages, be particularly useful for high-power soft switching arc welding inverter, be CO ₂Updating of the development of arc welding inverter and performance provides the direction of a development.

Accompanying drawing 2 is the utility model soft-switching inversion formula CO ₂Gas-shielded welder main circuit sketch, wherein, E is an input direct voltage, by the three-phase main-frequency alternating current through rectification, Lu ripple, be transformed to DC voltage E, about 540V, VT among the figure ₁～VT ₄Be IGBT power tube, VT ₁And VT ₃Respectively at VT ₄And VT ₂Turn-off before.VT ₁And VT ₃The brachium pontis of forming is called leading brachium pontis, then the switching tube VT of Guan Duaning ₄And VT ₂The brachium pontis of forming is called lagging leg.D ₁～D ₄Be respectively and VT ₁～VT ₄Antiparallel diode, C ₁～C ₄Be respectively VT ₁～VT ₄Parasitic capacitance and corresponding external resonant capacitance sum, establish C ₁=C ₂=C ₃=C ₄=C, L _1K, L _mBe respectively leakage inductance and the magnetizing inductance and the corresponding external resonant inductance sum of high-frequency power transformer, L _1K+L _m=L _sThe secondary side of transformer adopts the centre cap structure, with the end of the same name of " " expression winding, establishes the primary side of transformer, the ratio of the secondary side number of turn is N _P/ N _S=N _K, magnetic switch L _S1, L _S2Be connected on VT respectively ₁With VT ₂, VT ₃With VT ₄Between, increased a capacitance C ₅, D ₅, D ₆Be power transformer secondary side commutation diode, D ₇Be fly-wheel diode, L ₀, C _LForm output Lu ripple link, R _LBe load resistance, in this Novel Soft Switching arc welding inverter, utilize transformer leakage inductance to cooperate magnetizing inductance to realize that arc welding transformer is converted into the turning on and off of Zero-voltage soft switch of pure inductance state and lagging leg by afterflow.

Two, power output circuit

At present in the design of soft-switching arc welding inverter power output circuit, the control chip of phase shift pulse-width modulation circuit is selected UC3879 for use, this phase shift special chip UC3879 designs production for high-power soft switch phase shift arc welding inverter specially, the special chip of drive part adopts the most frequently used EXB841 at present, the switching frequency of special-purpose phase shift chip UC3879 also can reach 300kHz, has satisfied the requirement of arc welding inverter to high-frequency inversion.Simultaneously, had current control, under-voltage locking, soft start, phase-shift delay is provided with respectively, and the miscellaneous function that improves welding machine stability by all current detecting etc.

At present in full-bridge phase-shift ZVT converter, in order to satisfy the needs of ZVT, adopt the control method of voltage-type, triangle wave voltage by oscillator external capacitor two ends provides ramp signal, produce constant frequency and transfer wide PWM method, go to control 4 tunnel phase shift pulses of output again by the PWM square wave, its advantage is to be used for stablizing with error signal triangular wave relatively, the pulse width of the PWM method that produces is only relevant with error signal, be convenient to set the minimum phase shift angle, satisfy the needed time conditions of ZVT, come the peak value of control transformer primary side current by the method for wave limiting.

In full-bridge phase-shift no-voltage converter, the order that the conducting of power switch pipe is turn-offed is 1GBT ₁-IG6T ₄-IGBT ₃-IGBT ₂, these all are 4 tunnel phase shift pulses that are controlled by special chip UC3879 output, the switching tube of same brachium pontis is anti-phase conduit, conducting has phase shift to cornue, thereby changed, the time of leading altogether in special chip, when 2 switching tube conductings of same brachium pontis are turn-offed with the variation of phase shift, need certain delay time, lead directly to preventing, the safety of guaranteed output switching tube, the spy is provided with suitable delay time, delay time has the delay time of lead man and the delay time of lagging leg, IGBT ₁, IGBT ₃Claim lead man, IGBT ₄, IGBT ₂Be called lagging leg.

UC3879 phase shift special chip is standard dual inline type 20 pins, is the modified of UC3875, and OUTA, OUTB, OUTC, OUTD are 4 tunnel phase shift pulse, wherein R of UC3879 output ₁, C ₁Set the cycle of output pulse, the RAMP pin of chip meets C ₁, as producing the ramp signal that pwm signal is used.2,3 pin of chip amplify as the input of error signal and the error amplifier by inside.The CS-4 pin connects current signal, whether detects overcurrent.The electric capacity that connects between SS-6 pin and the ground is used for setting soft starting time.DLYA/B-15 pin connecting resistance, the delay time of setting OUTA and OUTB 2 tunnel pulses, the DLYC/D-5 pin is set the delay time of OUTC and OUTD 2 tunnel pulses.

By analysis, the minimum delay time of lead man is, i.e. OUTA and OUTB two-way pulse delay time

$t=\sqrt{2\mathrm{LC}}\&times;\mathrm{arutg}\left(\frac{I\max \sqrt{2\mathrm{LC}}}{\mathrm{NcUo}}\right)$

Imax is the maximum output current of welding machine in the formula.

U ₀Be welding machine input direct voltage value.

L is the resonant inductance value

C is the resonant capacitance value

N is transformer primary side, secondary side turn ratio.

The minimum delay time of lagging leg is the pulse delay time of OUTC and OUTD 2 tunnel

$T=\sqrt{2\mathrm{LC}}$

So the time-delays control of phase place modulation and four tunnel outputs is main features of special chip UC3879, and another characteristics of phase shift special chip to be the output of four output pulse OUTA-OUTB and time-delay that OUTC-OUTD exports can be provided with respectively.

A new function of UC3879 special chip is by all electric current restrictions, when current sampling signal surpasses the 2V benchmark of inner setting, is used for being provided with the first class of protection circuit by all electric current restrictions.For serious overload situations, UC3879 has also designed the second class protection circuit, when the current sampling signal of pin 4 (CS) is instantaneous when surpassing the 2.5V max threshold; UC3879 carries out once holocyclic soft start; if overload condition can not get changing, device can enter interrupt mode, avoids components from being damaged.

Special chip EXB841 is adopted in the driving of the power device of arc welding inverter.

The EXB841 chip be Japanese fuji company produce be exclusively used in driving power pipe IGBT, be widely used in Switching Power Supply, arc welding inverter etc.It is little that they have a volume; has over-current detection; functions such as grid protection and slow turn-off protection are fallen; device also is integrated with+15V open gate voltage and-5V closes gate voltage; to prevent the switch misoperation; the defencive function of this drive circuit is more complete, simple, reliable, is the optimal control chip of IGBT, favored by users.

But EXB841 in use finds the part that still comes with some shortcomings, and as the negative bias brownout, its inner 5V voltage-stabiliser tube very easily damages, and has influenced the reliability of arc welding inverter.

At the problem that EXB841 exists, its circuit has been done following improvement, added the degenerative analog line driver of the degree of depth at the output of EXB841, insert by four triode V at EXB841-3 pin ₁～V ₄The two-stage complementary drive circuit of forming, it is the totem-pote circuit structure, make output provide electric current to load, can absorb electric current to load again, this structure all is favourable to the turn-on and turn-off of power tube, EXB841-2 pin by originally+20V brings up to+30V, its voltage stabilizing value of the voltage-stabiliser tube of access promotes and is+15V, the 5V voltage-stabiliser tube that this has just remedied EXB841 inside, the deficiency of the negative bias brownout that causes.

Accompanying drawing 3 is the utility model soft-switching inversion formula CO ₂The gas-shielded welder power output circuit.

Power output circuit is driven by 1 phase shift special chip IC 20, four that special chip IC 22～IC25,1 two 4 input nand gate IC21,5 optocoupler PC5～PC9,25 triodes, 4 diodes, 12 zener diodes and resistance capacitance are some etc. to be formed.

Welding current is regulated through the welding current potentiometer, amplify through two-stage calculation amplifier, enter control chip IC20 by the on-off circuit passage of forming by IC8, IC9, it is the 3rd pin of UC3879,4 tunnel phase shift pulses are by pin 13,12,8,7 outputs of control chip UC3879, respectively by corresponding triode V ₃₀～V ₃₃Be input to the driving chip EXB841 of each self-corresponding special use, promptly the pin 14 of IC22～IC25 by IC22～IC25 pin 3 outputs, enters the two-stage complementary drive circuit of being made up of four triodes, removes to trigger the power tube that belongs to separately respectively.This improved two-stage complementary drive circuit, has degree of depth negative-feedback, has the totem-pote circuit structure again, help the rapid turn-on and turn-off of power tube energy under big electric current, the voltage that is added in pin 2 external power supplys is increased to+30V by original+20V, and the voltage stabilizing value of the voltage-stabiliser tube of access rises to+15V, overcome the low excessively deficiency of the inner back bias voltage of EXB841, fact proved that improved EXB841 drive circuit is the best power controller spare of present power tube IGBT, has greatly improved soft-switching inversion formula CO ₂The gas-shielded welder total quality.

When power tube wherein riches all the way when giving birth to overcurrent, establish power tube VT ₁Overcurrent takes place, V _IGBTV _CERising with electric current increases, when voltage increases to 3 ^VThe time, special-purpose diode D ₆₀Reverse-conducting; the protection system of forming by power drive special chip IC 22; enter guard mode immediately; chip IC 22 conductings; pin 6 voltages of IC22 are transformed to electronegative potential by high potential; cause that simultaneously chip IC 22 pin 5 become electronegative potential by high potential; cause optocoupler PC6 conducting; pin 1 becomes electronegative potential by high potential; pin 4 also becomes electronegative potential by high potential, make IC21 promptly 4012 the 2nd pin become electronegative potential by high potential, according to the characteristic of NAND gate; output 1 pin that causes IC21 also becomes high potential by electronegative potential; the pin 4 of IC20 becomes high level by electronegative potential, has blocked 4 tunnel output pulses of phase shift special chip IC 20, does not have the output of trigger impulse; whole welding current is 0, has played protective effect.

Three, wire-feed motor alignment circuit

The stability of the wire feed rate of wire-feed motor is crucial to gas shielded arc welding, and the wire feed rate shakiness will influence the droplet transfer, appearance of weld and welding quality, and stable in order to keep wire feed rate, the wire-feed motor alignment circuit that chooses is crucial.In gas metal-arc welding, according to the principle of arc self-regulation, the size of wire feed rate has determined the size of welding current, and therefore, the control quality of wire feed rate can directly have influence on stability and the appearance of weld and the welding quality of welding process.

The UC3637 chip is that U.S. Unitrode company produces, and is used for the motor control chip of two-way PWM speed governing, past CO ₂The wire feeding circuit of gas shielded welding machine is based on thyristor rectifier, adopts unijunction transistor to make phase-shift circuit, and with the circuit that discrete component is formed, debug difficulties, during especially little electric current, the stability of wire-feed motor is just undesirable.When replacing traditional driving control with the UC3637 chip, series of advantages such as it is few to have an element of use, and cost is low, and is efficient has the Electric Machine Control of wire feed requirement in being particularly suitable for welding, as at CO ₂In gas-shielded welder and the Lincoln weld, requiring can the forward wire feed and oppositely reel off raw silk from cocoons, and at this moment uses the UC3637 chip just to seem very suitable as kernel control chip.

UC3637 is applied to CO ₂The wire feeding circuit of gas shielded arc welding need not throw over relay, can realize the wire feed function by speed-regulating potentiometer, operate steadily under the motor low speed, and speed-regulating range width, circuit structure is simple, and reliable operation is easy to adjust, and antijamming capability is strong.

This machine adopts the direct current print(ed) motor to make wire feeding motor, changes rotating speed by regulating armature voltage, and the motor output characteristics is straight, good stability.

The main circuit of wire-feed motor is to adopt the full-bridge motor-drive circuit, by V ₁, V ₂, V ₃, V ₄Constitute four brachium pontis, motor is connected between the brachium pontis, diagonal angle brachium pontis V ₁, V ₄V ₂, V ₃Conducting simultaneously is as UC3637 output pulse A _OUTAnd B _OUTWhen pulsewidth equated, the average voltage that is added in the armature two ends was zero, and motor does not start.Work as A _OUTPulsewidth is greater than B _OUTDuring pulsewidth, motor just changes, and vice versa.Select V ₁, V ₂Should select P type structure road field-effect pipe for use, V ₃, V ₄Should select N type structure road field-effect pipe for use, drain current should be greater than 10A-15A, and is withstand voltage greater than 100V, four voltage-stablizer ZD ₁～ZD ₄Available 8V～12V voltage-stabiliser tube, triode V ₅～V ₈Form the promotion amplifying stage,, all adopt differential connection in order to guarantee better symmetry.

The PWM motor speed control circuit of using UC3637 chip formation has the following advantages: electric motor starting is rapid, when stopping, stablizing by motor friction, eliminated the static friction dead band, during the motor low-speed motion, each FET driving pulse broad helps the reliable conducting of FET, the low-speed running stationarity is good, and the electric machine speed regulation wide ranges is well suited for resembling CO ₂Gas is protected the place utilization down that the welding machine wire feeder requires speed-regulating range width like this.

The effect of wire-feed motor alignment circuit is the size according to the given signal of supply voltage, give control corresponding voltage of control circuit of wire-feed motor according to certain proportionate relationship, the control rotating speed of motor to regulate wire feed rate and welding current, realizes the conspiracy relation between weldingvoltage and the electric current.

Accompanying drawing 4 is the utility model soft-switching inversion formula CO ₂Gas-shielded welder wire-feed motor alignment circuit figure.

The wire-feed motor alignment circuit is owing to use chip UC3637, optocoupler PC1,4 power field effect pipe V ₁, V ₂, V ₃, V ₄, four promote level transistor V ₅, V ₆, V ₇, V ₈, four zener diodes and some resistance capacitances are formed, and wire-feed motor adopts printed motor.

The main circuit of wire-feed motor adopts the bridge-type power driving circuit, by four FET V ₁, V ₂, V ₃, V ₄Form four brachium pontis, V ₅, V ₆, V ₇, V ₈, four triodes form bridge-type and promote level, in order to guarantee better symmetry, stability, all to adopt differential connection, motor to be connected between the brachium pontis, V wherein ₁And V ₃Form a complementary symmetry circuit, V ₂And V ₄Form the another one complementary symmetry circuit, the armature of print(ed) motor is received between the output of these two circuit, forms bridge connection.When motor just changes, the A terminal potential is risen, the B terminal potential descends, V ₁And V ₃The conducting motor just changes, and vice versa.The AB two ends are equipotential, and motor does not change.The advantage of this connection is that two pairs of pipes switch mutually, supply voltage only needs 24V that the armature two ends are obtained+voltage about 20V, can reduce the possibility that second breakdown occurs, impact in order to suppress inductive load, crest voltage is to the loss of power tube, at the power tube two ends and connect a high extensive diode.

Connect arc welding gun switch, because the conducting of optocoupler PC3, the output positive voltage makes optocoupler PC1 conducting, triode V ₉, V ₁₀, V ₅₀Conducting successively.Simultaneously, positive voltage passes through V ₉Be input to IC3 pin 15, IC3 pin 7,4 output two-way PWM phase shift pulse control signals join on the promotion level of symmetry, connect wire feeding circuit, and wire feeding motor is made unloaded low-speed running.

In case welding, welding current is through current divider, the sampling current signal enters two steps/four steps sequence circuit, make control end 9 pin of IC8 analog switch switch to low level by high level, connect IC8 input 2,12 pin, welding current, voltage control signal enter the wire feeding motor armature, make wire-feed motor enter normal wire feed duty.

13,12 pin of IC3 are internal fault protection end, in the use, insert current sampling signal between pin 12,13; when this signal voltage surpassed 0.75mv, the pwm pulse of 4,7 pin of IC3 output was blocked, and stops wire feed; do not have the output of welding electric current, complete machine is played a protective role.

Four, crawl wire feed and arc welding gun switch control circuit

The crawl wire feeder is convenient and introduce for welding procedure, is core with the dual-threshold voltage comparator of compositions such as IC5, upper voltage limit U ₁By resistance R ₈₈, R ₈₇On dividing potential drop decision, lower limit U ₂By resistance R ₈₈, R ₈₉On dividing potential drop decision.

Press crawl wire feed switch S ₂The time, input voltage V ₁Be R ₈₆, R ₂And R in the remote-control box ₁Branch road is at R ₁On dividing potential drop because R ₁Bigger, so input voltage U ₁Higher, the comparator input high level, i.e. IC5-3, the 14 pin output of 8 pin IC-4 is high level, punctures ZD ₆, triode V ₁₃Conducting, optocoupler PC3 conducting, the PC3-8 pin is converted to electronegative potential by high potential, makes the PCI-2 pin become electronegative potential, and optocoupler PCI conducting is sent control signal into wire feeding circuit and is realized the crawl wire feed.

The arc welding gun switch signal control circuit, be to be core equally with chip IC 5, when pressing arc welding gun switch, IC5-12 pin input voltage is zero, IC5-14 pin output LOW voltage, optocoupler PC2 conducting work, PC2-3 pin output HIGH voltage, the IC18-9 pin is converted to electronegative potential by high potential, makes two steps/four steps sequence circuit enter duty.The high potential of IC5-8 pin output simultaneously, breakdown diode ZD ₆, triode V ₁₃Conducting, optocoupler PC3 conducting is through control circuit engage relay J ₄, J ₁, the master switch of connection welding machine is sent floating voltage, connects the wire-feed motor circuit, opens magnetic valve.For improving arcing initiation success rate, make welding machine be in slow wire feed and cooperate high-tension striking state.Perform the preparation of each side for the welding job of welding machine.

Accompanying drawing 5 is the utility model soft-switching inversion formula CO ₂Gas-shielded welder crawl wire feed and arc welding gun switch control circuit.

Crawl wire feed and arc welding gun switch control circuit are by arc welding gun switch S ₁, hand switch S ₂, double operational IC5, four optocoupler PC2, PC3, PC4, PC10, chip six homophases buffering transformer IC17, TC4050BP, six (four phase inverters/2 input nor gate/2 input nand gates) IC18, TC4572BP of chip, relay J ₁, J ₄Triode V ₁₃, V ₁₄, V ₁₅, V ₁₆, V ₂₂, V ₂₃, V ₂₄And some resistance capacitances, compositions such as diode.

The crawl wire feed is different with the arc welding gun switch circuit, just in the crawl wire feed switch big resistance resistance R of having connected ₁, because R ₁Resistance is big, is input to IC5-12 pin current potential height, IC5-14 pin output high potential, and optocoupler PCI closes, and arc welding gun switch S ₁There is not series resistance, when pressing arc welding gun switch S ₁, directly ground connection adds R ₂Resistance is very little, and it is almost nil to be input to IC5-12 pin current potential, the IC5-14 output LOW voltage, make optocoupler PC2 conducting, optocoupler PC2-3 pin is a high potential by the electronegative potential upset, and the IC18-9 pin is converted to electronegative potential by high potential, makes two steps/four steps sequence circuit enter working state of system.

Five, the receipts arc circuit and two steps/four steps sequence circuit that have auto-lock function

Different according to the size of gage of wire and welding current and weld seam length, the program of the welding process that is adopted is also different, and when little at welding current, weld seam is shorter, generally adopts simple two step control programs.On the welding machine panel, being provided with receipts arc change-over switch " has " and " nothing ", will receive the arc switch transition to " nothing ", promptly refers to two step control programs.Press arc welding gun switch this moment, begins to supply gas, and begins wire feed behind about 0.5S that lags behind, and export floating voltage simultaneously, enters welding process subsequently, whole welding process, and hand will be pinned arc welding gun switch always.When needs finish welding, unclamp arc welding gun switch, stop wire feed immediately, lagging behind stops to supply gas, and powered-down finishes whole welding process.

If welding current is big, weld seam is long, and the impulsive force of electric current is stronger, adopt two step control programs can produce darker arc crater, this position is easy to generate defective, and, if weld seam is longer, adopt two step control programs to pin arc welding gun switch always, working strength of workers is big.In this case, need to adopt, i.e. four step control programs than complicated process.The receipts arc change-over switch that at first the welding machine panel is provided with is transformed into " having ", presets the voltage and current of filling arc crater.When pressing arc welding gun switch, the output floating voltage begins to supply gas, and the beginning wire feed that lags behind enters welding process, and process is with two step control programs.But unclamp arc welding gun switch, system's self-locking enters four step control programs, and welding process continues.When pressing arc welding gun switch once more, system's release, welding current and voltage reduce, and begin to fill arc crater, treat that arc crater fills up after, unclamp arc welding gun switch, stop wire feed, time-delay is died, last delay cut-off, whole welding process finishes.

Accompanying drawing 6 is the utility model soft-switching inversion formula CO ₂Gas is protected welding machine, has the receipts arc circuit and two steps/four steps sequence circuit of auto-lock function.

Receipts arc circuit and two steps/four steps sequence circuit with auto-lock function are by IC6, IC7 four high guaily unit 324, IC10 NAND gate 4011, IC11 or door 4071, IC12, IC13 and door 4081, IC14 phase inverter 4069, IC15, IC16 is a d type flip flop 4013, triode V ₁₇, V ₁₈, V ₁₉, V ₂₀, V ₂₁And each resistance capacitance, compositions such as diode.

On the welding machine panel, be provided with and receive the arc change-over switch, there is the arc of receipts to be " having ", not having the arc of receipts is " nothing ", and it is four step control programs that the arc of receipts is arranged, and not having the arc of receipts is two step control programs.

D type flip flop 4013 is the devices with memory function, is the trigger that has only a signal controlling end, and after input signal disappeared, the output state of trigger remained unchanged, till input signal again.

To receive the arc change-over switch before the welding and place " having ", preset the electric current and the voltage of filling arc crater.Press the arc welding gun switch button, IC5-8 pin output high level, IC5-14 pin output low level makes optocoupler PC3 and PC2 conducting work, through resistance R ₉₆, R ₉₇Control signal is input in two steps/four steps control circuit.

With NAND gate 4011, IC10-1, IC10-2 forms rest-set flip-flop.

The self-locking systems of four step control circuits are by IC16, d type flip flop 4013 or door IC11, and 4071, with door IC13,4081, and NAND gate IC10,4011, triode V ₁₇, V ₁₈Compositions such as resistance capacitance.

Control signal enters d type flip flop 4013, IC16 through rest-set flip-flop, and IC15 is exporting a positive voltage with door IC12-3 pin.Be added to d type flip flop 4013, promptly the D of IC16 holds 9 pin, and according to the characteristic of d type flip flop, θ exports a positive voltage at its output, makes relay J ₁, J ₄Conducting makes main transformer work, relay J ₃Magnetic valve is connected in conducting simultaneously, begins to supply gas, and connects wire feeding circuit simultaneously, the beginning wire feed.Make main control chip IC 20 that power supply has been arranged simultaneously, export four road phase-shift pulses, trigger power tube, the output floating voltage.Analog switch pipe IC8, three control voltage selecting sides of CD4053, pin 9,10,11 places 0,0,0 state, switching tube IC8,2 pin of CD4053 and 12 pin conductings, output-controlled in welding current and voltage, current and voltage signals performs the preparation of each side for the welding of welding machine.

Begin welding, in order to alleviate welder's fatigue, unclamp arc welding gun switch, because sequence circuit has auto-lock function, welding is carried out in the same old way, and welding reopens arc welding gun switch before finishing, and sequence circuit is removed auto-lock function.Simultaneously, switch is subjected to IC8, and three of CD4053 control voltage selecting side A, promptly 9,10,11 pin are by 0,0 for B, C, and 0 state switches to 1,0, and 0.The passage of switching tube 4053 switches to 13,1 by 12,2.Fill arc crater with the electric current that presets in advance and voltage, treat that arc crater fills up after, unclamp arc welding gun switch, whole welding process finishes.

Two step sequence circuits at first will be received the arc change-over switch and push on " nothing " word, not have the auto-lock function of receiving arc in welding process.Whole welding process is pinned the welding gun button with hand, finishes up to welding, and hand just can leave arc welding gun switch.

Six, the unified regulating circuit of welding parameter

The unified adjusting of welding parameter is the main feature of welding machine; it not only makes the wire feed rate of wire feeding motor adjust movingly certainly with electric power output voltage; and can be according to different welding materials; protective gas and gage of wire carry out parameters selection; to welding current, voltage also will carry out necessary unified adjusting, thereby makes the precision of unified adjusting higher equally; what cooperate is wider, regulates simpler.Realized with the unified adjustment of the preferential welding parameter of voltage with this.In unified control, core is that welding wire is selected circuit, promptly according to the size of gage of wire, realizes the different transformation of scale of voltage given Gu.

Accompanying drawing 7 is the unified regulating circuit figure of the utility model welding parameter

This circuit is mainly by four high guaily unit IC1-1, IC1-2, IC1-3, IC1-4, four high guaily unit IC2-1, IC2-2, IC2-3, IC2-4, four high guaily unit IC4-1～IC4-4, four high guaily unit IC5-1～IC5-4, analog switch IC8, compositions such as IC9 and relevant resistance capacitance.Under different gage of wire conditions, analog switch IC9 provides different I/O channels.When selecting Φ 1mm welding wire for use, by unified regulating circuit, the control voltage of the control end of its analog switch IC9 is that 0,0,0 input channel 5,2,12 is connected with output channel 14,15,4.If when selecting Φ 1.2mm welding wire for use, because of its control level is 1,0,0, input channel 5,2,13 connect with output channel 14,15,4.Different on off states makes voltage given signal Gu, and the given signal Gi of electric current is via four high guaily unit IC1-1, R ₅, R ₇, R ₈, R ₇₉With VRi, VRu, D in the remote-control box on the wire-feed motor ₁₇, D ₁₈Form the square wave oscillation circuit, by electric current, the voltage-regulation potentiometer Vri of remote-control box, VRu regulates the positive negative pulse stuffing peak value of square wave, is coupled to the inverting input of IC1-3 and the in-phase end of IC1-4 through emitter follower IC1-2 respectively.The negative peak of square wave is inoperative to IC1-4, and by the output of IC1-3 the 8th pin, the forward value is by the 14 pin output of IC1-4, the output that is IC1-3 is determined by the square wave negative peak, can be regulated by VRu, the output of IC1-4 can be regulated by VRi by the decision of square wave forward peak value.Title VRi is a welding regulator, can regulate the welding current value, and the unified adjusting of visible welding parameter makes voltage adjust along with the current value of setting carries out inner oneself, and this self-regulated is called unified adjustment.Claim that VRu is the weldingvoltage adjuster, can regulate welding voltage value.Can be the fine adjustment of VRu as unified adjusting weldingvoltage, welding parameter is unified, is subjected to the welding position, the welding wire kind, influences such as the length of prolongation cable and electrode extension even the weldingvoltage adjuster places normal place sometimes, often also can not get only weldingvoltage.At this moment, can use this adjuster to finely tune, promptly turning left is " low slightly ", and turn right " high slightly " like this, can obtain the splendid value of weldingvoltage.

VRu and VRi by easy unified setting, be that weldingvoltage is regulated and welding current is regulated, after four high guaily unit IC1-3 and IC1-4 amplification, enter with welding material different with gage of wire and form another unified control circuit through 12 pin, 2 pin of analog switch IC8, again through four high guaily unit IC5-1, after IC5-2 amplifies, be input to the armature of wire-feed motor, become the control voltage of wire-feed motor armature.The control voltage G of wire-feed motor armature _KsJust can adapt to the different requirements of different welding wire conditions, obtain the effect of satisfied unified adjusting.Since non-linear relation between voltage and the electric current, under little standard, IC1-3,8 pin output valves are bigger, under big standard, IC1-4,14 pin output valves are lower, thereby obtained under big electric current and the little electric current the different proportionate relationship between the voltage and current respectively.

Claims (3)

1, a kind of novel soft-switching inversion formula CO ₂Gas-shielded welder, it is by electric power main circuit, power output control circuit, the alignment circuit of wire-feed motor, crawl wire feed and arc welding gun switch circuit, receipts arc circuit and two steps/four with auto-lock function go on foot sequence circuit, and the circuit such as unified circuit that welding parameter is selected are formed, it is characterized in that soft-switching inversion formula CO ₂Gas-shielded welder, the welding machine of this form adopts magnetic switch to enable the magnetizing inductance of optimization, cooperate leakage inductance and distributed inductance simultaneously, realize this new-type circuit of Zero-voltage soft switch, solve arc welding inverter and hour can't realize the problem of the soft switch change of current at zero load and welding current, have unique advantages, be particularly useful for high-power soft switching arc welding inverter, be CO ₂Updating of the development of arc welding inverter and performance provides the direction of a development.

2, soft-switching inversion formula CO according to claim 1 ₂Gas shielded welding machine is characterized in that, has at length introduced each part of this new welder in specification; Electric power main circuit, power output control circuit, the alignment circuit of wire-feed motor, crawl wire feed and arc welding gun switch circuit, receipts arc circuit and two steps/four with auto-lock function go on foot sequence circuit, the unified circuit that welding parameter is selected.

3, soft-switching inversion formula CO according to claim 2 ₂Gas shielded welding machine; it is characterized in that the main circuit of its power supply, power output control circuit; the alignment circuit of wire-feed motor; crawl wire feed and arc welding gun switch circuit, receipts arc circuit and two steps/four with auto-lock function go on foot sequence circuit, the unified circuit that welding parameter is selected; the detailed content of being set forth is the core of the utility model claim; its core content as what set forth in the specification, no longer repeats here.

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