CN202479668U - Single-tube IGBT (insulated gate bipolar translator) inverter-type electric arc welder - Google Patents

Abstract

The utility model relates to the field of electric welders, in particular to a single-tube IGBT (insulated gate bipolar translator) inverter-type electric arc welder. The single-tube IGBT inverter-type electric arc welder comprises a master circuit and a control circuit which are sequentially connected through an electrical signal, wherein the master circuit comprises an alternating current input end, a power frequency rectifier filter and power supply circuit, an intermediate frequency inverter circuit, an intermediate frequency voltage reducing transformer, an intermediate frequency rectifier circuit, an intermediate frequency filter inductor and a direct current output end; the control circuit comprises a power frequency control transformer, a master control and PWM (pulse width modulation) circuit and a displaying and regulating circuit; the intermediate frequency inverter circuit is a bridge-type inverter circuit comprising a single-tube IGBT set and a symmetrical driving circuit; and the master control and PWM circuit is connected with the intermediate frequency inverter circuit and is used for driving the intermediate frequency inverter circuit according to a received signal. The single-tube IGBT inverter-type electric arc welder adopts a single-tube IGBT, so that the production is very low and the integral volume is reduced; and the welding effect is very good.

Description

A kind of single tube IGBT contravariant arc welder

Technical field

The utility model relates to the electric welding machine product scope, is specifically related to a kind of single tube IGBT contravariant arc welder

Background technology

contravariant arc welder is the novel source of welding current of a kind of high-efficiency environment friendly, energy-saving material-saving; Along with the development of power semiconductor switches device, the contravariant arc welder has successively experienced fast controllable silicon inverter mode, transistor (BJT) inverter mode, isolated gate FET (MOSFET) inverter mode to development courses such as isolated-gate field effect transistor (IGFET) (IGBT) inverter modes.At present, IGBT contravariant pattern arc welder is that technology is comparatively advanced at present, because the electric property of IGBT pipe all is superior to other semiconductor switch devices, switching frequency is far above controllable silicon and transistor; And saturation voltage drop is far below isolated gate FET.Because the inversion operating frequency is very high, so the area of core section of its main transformer and coil turn significantly reduce, therefore, IGBT contravariant welding machine can reduce volume and the weight of self to a certain extent, significantly reduces electric energy loss.But, in present IGBT contravariant arc welder, all need use powerful IGBT module, make it on volume, still have the space of further minimizing, and its caloric value is big, and is unfavorable for heat radiation; And the cost of its production and maintenance thereof is all very high, is unfavorable for the popularization in market

Summary of the invention

for overcoming above-mentioned defective, the purpose of the utility model promptly is a kind of single tube IGBT contravariant arc welder.

The purpose of the utility model realizes through following technical scheme:

A kind of single tube IGBT of the utility model contravariant arc welder mainly comprises:

Main line and control circuit;

Said main line is made up of the ac input end that is linked in sequence successively through the signal of telecommunication, industrial frequency rectifying filtering and power supply circuits, medium frequency inverter circuit, intermediate frequency step-down transformer, intermediate frequency rectification circuit, intermediate frequency filtering inductance and dc output end;

Said control circuit comprises: power frequency control transformer, master control and PWM pulse-width modulation circuit and demonstration and regulating circuit;

Said industrial frequency rectifying filtering and power supply circuits also are connected with master control and PWM pulse-width modulation circuit through the power frequency control transformer;

Said medium frequency inverter circuit wherein also is provided with current sampling circuit for the bridge inverter main circuit of single tube IGBT group and symmetrical drive circuit formation, and the current feedback signal that said current sampling circuit obtains sampling is sent to master control and PWM pulse-width modulation circuit;

Be provided with voltage sampling circuit in the said dc output end, the voltage feedback signal that said voltage sampling circuit obtains sampling is sent to master control and PWM pulse-width modulation circuit;

Said master control is joined with PWM pulse-width modulation circuit and medium frequency inverter circuit, is used for driving the medium frequency inverter circuit according to the signal that receives;

said demonstration and regulating circuit and master control and PWM pulse-width modulation circuit two-way admittance are used for showing to master control and PWM pulse-width modulation circuit input control signal and to the signal of master control and PWM pulse-width modulation circuit.

are further, and said master control and PWM pulse-width modulation circuit comprise: current feedback system, striking electric current give fixed system, overcurrent protection signal system, pwm pulse power amplifying system, pwm pulse control system for fixed system, welding current for fixed system, push current.

Further, said medium frequency inverter circuit comprises: four groups of switching tubes, and it is respectively: first group of switching tube, second group of switching tube, the 3rd group of switching tube, the 4th group of switching tube;

Said first group of switching tube comprises: IGBT single tube Q1a and Q1b, capacitance-resistance absorption resistance R13 and R14, capacitance-resistance absorb capacitor C 9 and C10, gate-drive resistance R 15 and R16;

Said second group of switching tube comprises: IGBT single tube Q2a and Q2b, capacitance-resistance absorption resistance R19 and R20, capacitance-resistance absorb capacitor C 11 and C12, gate-drive resistance R 17 and R18;

Said the 3rd group of switching tube comprises: IGBT single tube Q3a and Q3b, capacitance-resistance absorption resistance R11 and R12, capacitance-resistance absorb capacitor C 5 and C6, gate-drive resistance R 9 and R10;

said the 4th group of switching tube comprises: IGBT single tube Q4a and Q4b, capacitance-resistance absorption resistance R21 and R22, capacitance-resistance absorb capacitor C 15 and C16, gate-drive resistance R 23 and R24.

are further, said first, the 4th group with the break-make of second, third group switching tube phasic difference 180 degree mutually.

are further, and said industrial frequency rectifying filtering and power supply circuits comprise: current feedback system, striking electric current give fixed system, overcurrent protection signal system, pwm pulse power amplifying system, pwm pulse control system for fixed system, welding current for fixed system, push current.

are further; Said intermediate frequency step-down transformer is by once surveying the intermediate frequency step-down transformer that winding and secondary side full-wave rectification winding and transformer core are formed; One of first side winding is refuted and is connected to inverter bridge one mid point; The other end is then refuted and is connected to another mid point of inverter bridge, secondaryly delivers to said intermediate frequency rectification circuit.

Further, said pwm pulse control system comprises:

Integrated circuit U2, said integrated circuit U2 are used for being responsible for generation, frequency division and the misphase of pwm pulse and the output of pwm pulse;

Pwm pulse is decided hunting of frequency electric capacity and resistance, and said pwm pulse decides hunting of frequency electric capacity and resistance is made up of capacitor C 8 and resistance R 22;

Soft starting circuit, said soft starting circuit is made up of resistance R 15, R16 capacitor C 13;

Under-voltage protecting circuit, said under-voltage protecting circuit is made up of integrated circuit U1B and resistance R 18, R19 capacitor C 12 diode D4, is used to see off 16 pin that high level removes integrated circuit U2, to turn-off pwm pulse;

The sawtooth waveforms compensating circuit, said sawtooth waveforms compensating circuit is made up of integrated circuit U1C and resistance R 13, R14 capacitor C 9, C10, is used for the sawtooth signal voltage that 8 pin of integrated circuit U2 are exported is penetrated with after amplifying, and delivers to 4 pin of U2 through resistance-capacitance network;

Error ratio, amplification, integration adjustment circuit, said error ratio is, amplification, integration adjustment circuit be made up of integrated circuit U1A, be used for to signal carry out error ratio, amplification and integration adjustment;

emitter follower circuit, said emitter follower circuit is made up of integrated circuit U1D, be used for through error ratio, amplification and the adjusted signal of integration penetrate with 5 pin of sending into integrated circuit U2 after amplifying.

The medium frequency inverter circuit of the utility model is made up of several single tubes IGBT; Its production prices are very cheap; And because single tube IGBT caloric value is not high; Thermal resistance is little, makes whole device no longer need utilize large-scale heat abstractor to dispel the heat, and has further reduced the volume of complete machine; And, through the control of master control in the utility model and PWM pulse-width modulation circuit, make the utility model in the extremely short time, to adjust, thereby can satisfy the various specific (special) requirements in the welding process that welding effect is very good to output current.

Description of drawings

In order to be easy to explanation, the utility model is done to describe in detail by following preferred embodiment and accompanying drawing .

Fig. 1 is the circuit logic diagram of the utility model;

Fig. 2 is the piece electrical schematic diagram of the utility model;

Fig. 3 is the master control and the PWM pulse-width modulation circuit electrical schematic diagram of the utility model;

Fig. 4 is the pwm chip electrical schematic diagram of the utility model.

The specific embodiment

For the purpose, technical scheme and the advantage that make the utility model is clearer,, the utility model is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the utility model, and be not used in qualification the utility model.

See also Fig. 1 to Fig. 2, a kind of single tube IGBT of the utility model contravariant arc welder mainly comprises:

Main line and control circuit;

Said main line is made up of the ac input end that is linked in sequence successively through the signal of telecommunication, industrial frequency rectifying filtering and power supply circuits 1, medium frequency inverter circuit 2, intermediate frequency step-down transformer 3, intermediate frequency rectification circuit 4, intermediate frequency filtering inductance 5 and dc output end;

Said control circuit comprises: power frequency control transformer 8, master control and PWM pulse-width modulation circuit 6 and demonstration and regulating circuit 7;

Said industrial frequency rectifying filtering and power supply circuits 1 also are connected with master control and PWM pulse-width modulation circuit 6 through power frequency control transformer 8;

Said medium frequency inverter circuit 2 is the bridge inverter main circuit of single tube IGBT group and symmetrical drive circuit formation; Wherein also be provided with current sampling circuit (not shown), the current feedback signal that said current sampling circuit (not shown) obtains sampling is sent to master control and PWM pulse-width modulation circuit 6;

Be provided with voltage sampling circuit (not shown) in the said dc output end, the voltage feedback signal that said voltage sampling circuit (not shown) obtains sampling is sent to master control and PWM pulse-width modulation circuit 6;

Said master control and PWM pulse-width modulation circuit 6 join with medium frequency inverter circuit 2, are used for driving medium frequency inverter circuit 2 according to the signal that receives;

said demonstration and regulating circuit 7 and master control and PWM pulse-width modulation circuit 6 two-way admittances are used for showing to master control and PWM pulse-width modulation circuit 6 input control signals and to the signal of master control and PWM pulse-width modulation circuit 6.

The concrete course of work of the utility model is:

Behind electrical network industrial-frequency alternating current input welding machine; Industrial frequency rectifying filter circuit through in industrial frequency rectifying filtering and the power supply circuits 1 carries out rectifying and wave-filtering; Obtain DC current or voltage; Again DC current or voltage are supplied with medium frequency inverter circuit 2, deliver to power frequency control transformer 8 after simultaneously the electrical network industrial-frequency alternating current being handled through EMC, after the 8 suitable step-downs of power frequency control transformer the low voltage control alternating current is delivered on master control and the PWM pulse-width modulation circuit.Blower fan power supply circuits in industrial frequency rectifying filtering and the power supply circuits 1 are being undertaken the task that AC energy is provided for axial flow blower.The bridge inverter main circuit that medium frequency inverter circuit 2 is made up of single tube IGBT pipe; DC voltage or current inversion are become intermediate frequency square wave alternating-current voltage or electric current; Deliver to the primary side of intermediate frequency step-down transformer 3; Deliver to intermediate frequency rectification circuit 4 after the step-down again and be rectified into intermediate frequency pulsating dc voltage or electric current, through the laggard line output of intermediate frequency filtering inductance 5 filtering ripples.

are provided with current sampling circuit at the primary side of medium frequency inverter circuit 2, and the current signal of adopting is delivered to master control and PWM pulse-width modulation circuit 6 as current feedback signal; Demonstration is also delivered to master control and PWM pulse-width modulation circuit 6 with the given signal of current/voltage that regulating circuit 7 is sent here; Be provided with voltage sampling circuit in output place; The voltage signal of adopting is also delivered to master control and PWM pulse-width modulation circuit 6 as voltage feedback signal; Three road signals here carry out error ratio, integration amplifies and quiet external characteristics control back modulation (PWM) pulse; Power amplification pwm pulse, output at last have the PWM driving pulse of certain power to go to drive the single tube IGBT group of medium frequency inverter circuit 2.

master control and PWM pulse-width modulation circuit 6 are two-way UNICOMs with the signal of demonstration and regulating circuit 7; Show that the given signal that produces with regulating circuit 7 delivers to master control and PWM pulse-width modulation circuit 6, signal such as the overcurrent of master control simultaneously and PWM pulse-width modulation circuit 6/overheated/under-voltage and welding current value also will show through the man-machine interface of demonstration and regulating circuit 7.

described industrial frequency rectifying filtering and power supply circuits 1 are made up of rectifier bridge QL1, filter capacitor C1 and C2 and input and output socket P3, P8, P9 etc.Industrial-frequency alternating current is delivered on industrial frequency rectifying filtering and the power supply circuits 1 through air switch K1, by transporting to the next stage circuit after rectifier bridge QL1 rectification and capacitor C 1, the C2 filtering.Socket P9 is connected to primary side and the primary side of Industrial Frequency Transformer 8 from the lotus root tap; Industrial Frequency Transformer T2 will give axial flow blower FAN1 through socket P3 from the voltage after the lotus root step-down, the voltage of Industrial Frequency Transformer T2 after with isolated buck through socket X6 deliver to master control and PWM pulse-width modulation circuit 6 as control with power supply.Industrial frequency rectifying filtering and power supply circuits 1 also comprise under-voltage identification circuit, and under-voltage signal is delivered to master control and PWM pulse-width modulation circuit 6 as the under-voltage protection signal through socket P8 and X9.

said medium frequency inverter circuit 2 is the bridge inverter main circuits that are made up of four groups of single tube IGBT groups and symmetrical drive circuit; IGBT single tube Q1a and Q1b, capacitance-resistance absorption resistance R13 and R14, capacitance-resistance absorb capacitor C 9 and C10, gate-drive resistance R 15 and R16 etc. and form first group of switching tube; IGBT single tube Q2a and Q2b, capacitance-resistance absorption resistance R19 and R20, capacitance-resistance absorb capacitor C 11 and C12, gate-drive resistance R 17 and R18 etc. and form second group of switching tube; IGBT single tube Q3a and Q3b, capacitance-resistance absorption resistance R11 and R12, capacitance-resistance absorb capacitor C 5 and C6, gate-drive resistance R 9 and R10 etc. and form the 3rd group of switching tube, and IGBT single tube Q4a and Q4b, capacitance-resistance absorption resistance R21 and R22, capacitance-resistance absorb capacitor C 15 and C16, gate-drive resistance R 23 and R24 etc. and form the 4th group of switching tube.Pwm pulse signal takes out from master control and PWM pulse-width modulation circuit 6 through socket X7; Deliver to and deliver to respectively on the gate pole of four groups of single tube IGBT groups after symmetrical drive circuit is isolated phase-splitting; Driving four groups of single tube IGBT respectively presses: first group with the 4th group of IGBT conducting simultaneously and shutoff; Second group with the 3rd group of IGBT conducting simultaneously and shutoff, first, the 4th group with the break-make of second, third group IGBT phasic difference 180 degree mutually.Wherein capacitor C8, C14 and C13 are inverter dc bus high-frequency filter capacitor, are used for the high frequency peak voltage that produces on the filtering bus.Be provided with primary side current in the medium frequency inverter circuit 2 and detect feedback circuit, circuit is made up of current transformer T3, fast-recovery commutation diode D13, D14, D15, D16, sampling resistor R26 and high-frequency filter capacitor C21 etc.By sampling resistor R26 adopt amplitude and the proportional pulse voltage signal of primary side pulse current will be as the feedback signal of welding current.

said intermediate frequency step-down transformer 3 is by once surveying the intermediate frequency step-down transformer that winding and secondary side full-wave rectification winding and transformer core are formed; One of first side winding is refuted and is connected to inverter bridge one mid point; The other end is then refuted and is connected to another mid point of inverter bridge, the secondary intermediate frequency rectification circuit 4 of delivering to.First side winding and Secondary Winding are through the insulating materials safe insulation.

said intermediate frequency rectification circuit 4 is formed all-wave intermediate frequency rectification circuit by fast-recovery commutation diode D5, D6, D7, D8 and capacitance-resistance absorption resistance electric capacity R25, C17 and fast-recovery commutation diode D9, D10, D11, D12 and capacitance-resistance absorption resistance electric capacity R26, C18 etc.

said intermediate frequency filtering circuit 5 is a direct current filter inductance L1, and the direct current behind the filtering intermediate frequency ripple is from the output of direct current delivery outlet, and the both positive and negative polarity and the capacitor C between the ground 19 that are connected to delivery outlet are the safety electric capacity of anti-interference ground connection with C20.

said master control and PWM pulse-width modulation circuit 6 comprise: current feedback system, striking electric current give fixed system, overcurrent protection signal system, pwm pulse power amplifying system, pwm pulse control system for fixed system, welding current for fixed system, push current.

said demonstration and regulating circuit 7 are made up of LED digital current display gauge head, overcurrent/overheated/under-voltage indicator lamp, push current setting knob and welding current setting knob, can accomplish man-machine interchange through the human-computer dialogue panel of this circuit.

Please referring to Fig. 3, be in the particular circuit configurations of master control described in the utility model and PWM pulse-width modulation circuit:

said current feedback system is made up of integrated circuit U1D and resistance R 1, R2, R3 capacitor C 1 diode Z2 and D1.

said striking electric current is made up of for fixed system integrated circuit U1C, U1A resistance R 29, R30, R31, R32, R33, R34, R19, R20 capacitor C 12, C11, C10, C13, C7 diode D4, D5, D7.

said overcurrent protection signal system is formed over-current signal comparison process, output and display circuit and is formed by triode Q3, Q4, Q5, Q6 photoelectrical coupler U3 resistance R 35, R36, R37, R38, R39, R40, R41, R42, R28 capacitor C 14, C16 diode D8, D9.In addition, constitute under-voltage/overtemperature prote and display circuit by diode D6, D10 resistance R 26, R27 capacitor C 9 and external under-voltage sampling and temperature relay.

said push current is made up of for fixed system integrated circuit U2A, U2B, U2D resistance R 16, R17, R18, R11, R7, R8, R9, R10, R4, R5, R6 capacitor C 2, C3, C4, C5 diode D2, D3, Z1 etc.

said welding current is made up of for fixed system integrated circuit U2C resistance R 12, R13, R14, R15 capacitor C 6 potentiometer W1, W2 etc.

said pwm pulse power amplifying system is managed M1, M2, M3, M4 resistance R 45, R46, R47, R48, R43, R44 capacitor C 15, C33, C34, C35, C17, C18, C19 etc. by MOSFET and is formed.

said pwm pulse control system is pwm pulse control chip CZ1, and it is made up of integrated circuit U1A, U1B, U1C, U1D, U2 resistance R 1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R22 capacitor C 1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15 diode D1, D2, D3, D4, ZD1 etc.

wherein: integrated circuit U2 is a pwm chip, is responsible for the output of generation, frequency division and the 180 degree misphases and the pwm pulse of pwm pulse; Capacitor C 8 and resistance R 22 are that the pwm pulse of chip is decided hunting of frequency electric capacity and resistance; Resistance R 15, R16 capacitor C 13 formed soft starting circuits, and it opens pwm pulse with broadening mode at a slow speed when recovering; Integrated circuit U1B and resistance R 18, R19 capacitor C 12 diode D4 form under-voltage protecting circuit; When burning voltage is lower than 15V; Show that abnormal duty may appear in entire circuit, see high level off through this circuit and go 16 pin of integrated circuit U2 to turn-off pwm pulse; Integrated circuit U1C and resistance R 13, R14 capacitor C 9, C10 form the sawtooth waveforms compensating circuit; The sawtooth signal voltage that 8 pin of integrated circuit U2 are exported is penetrated with after amplifying; Deliver to 4 pin of U2 through resistance-capacitance network, with the pulse current waveform of compensation primary side feedback; Integrated circuit U1A and peripheral devices form error ratio, amplification, integration adjustment circuit; Integrated circuit U1D is an emitter follower circuit, will pass through error ratio, amplification and the adjusted signal of integration penetrate with 5 pin of sending into integrated circuit U2 after amplifying.

please referring to Fig. 4, the core parts U2 of pwm chip CZ1 is a current mode PWM integrated circuit UC3846 in the utility model, and it is responsible for, and pwm pulse produces and modulation output.

" 2 " pin of pwm chip is a current feedback terminal; " 5 " pin is the electric current given side; Current feedback signal that attracts from the outside and given signal are delivered to error comparison point through resistance R 1 with R2 through " 2 " pin and " 5 " pin respectively, i.e. the tie point of R1 and R2 is after the amplifier integration amplification through integrated transporting discharging U1A and U1D composition; Deliver to the 5PIN of current mode PWM integrated circuit U2, as the error voltage of PWM adjusting.

The primary side current pulse signal is introduced from " 13 " pin in , delivers to the 4PIN that current signal is relatively held integrated circuit U2 through resistance R 10; Also deliver to the 4PIN of integrated circuit U2 behind the oblique wave compensation network of the internal oscillator sawtooth signal of its 8PIN through the U1C composition; Be mixed at last through oblique wave compensation the primary side current pulse signal; Form the modulation (PWM) pulse inner the comparing of integrated circuit U2, through the pwm pulse signal after 11PIN and 14PIN output phase differ the modulation of 180 degree after frequency division, the phase-splitting with error signal.Introduce the primary side current pulse signal from " 13 " pin simultaneously; Also deliver to overcurrent and close broken ends of fractured bone 16PIN through resistance R 8; When having unusual over-current phenomenon avoidance, the inverter circuit primary side takes place; The primary side current pulse signal has the amplitude that exceeds the set threshold voltage value of U2, and U2 can stop to play pulse overcurrent protection one by one when prepulse output immediately.

The 1PIN of integrated circuit U2 is a shutoff/soft start end, when its ground connection, can turn-off pwm pulse output.After the 1PIN of start beginning or U2 breaks off with ground, the inside 5.1V voltage-stabilized power supply of 2PIN or capacitor C 13 slowly charge through divider resistance R15, R16,1PIN voltage can slowly raise from zero, and pwm pulse will be from zero width broadening gradually.So guard signals such as overheated, under-voltage, overcurrent are sent in this end, as long as signal such as overheated, under-voltage, overcurrent is arranged, this end just joins with ground, and voltage reduces to zero immediately, stops pwm pulse output immediately.Deng recover normal after, this end and ground are broken off, electric capacity slowly charges, pwm pulse will be from zero width broadening gradually.Play and unusual turn-off rapidly, recover normal or just start back pwm pulse from the zero width desirable soft start effect of broadening gradually.

The implementation that current feedback and electric current are regulated in the utility model is specially:

The current sampling circuit of inverter primary side collects the current pulse signal voltage of primary side; Introduce control circuit board through socket X7; Through resistance R 1 and R2 dividing potential drop; The U1D emitter following amplifies diode D1 isolation back and is filtered into direct current as current feedback signal by capacitor C 1, delivers to the error comparison point of pwm chip through " 2 " pin; The given signal of electric current that is provided by external potentiometer is integrated the negative given signal of electric current that generates after the processing such as circuit U 2C resistance R 12, R13, R14, R15 capacitor C 6 potentiometer W1, W2 is also delivered to pwm chip through " 5 " pin error comparison point; Push current will be welded arc voltage through resistance R 4, R5, R6 dividing potential drop to fixed system, and capacitor C 2 filtering are taken back on the potential difference comparator after U2B is delivered in the amplification of U2A emitter following and resistance R 8, R10, R7, R9 form.The output of comparator is transported to external thrust regulation potentiometer through diode D3 isolation; After external thrust regulation potentiometer is regulated, send back to, amplify the error comparison point of delivering to pwm chip through " 5 " pin by integrated circuit U2D anti-phase ratio after capacitor C 5 filtering interfering by socket X3; The striking electric current amplifies primary side current signal pulse signal voltage to fixed system through integrated circuit U1C homophase; Become the voltage signal that characterizes the primary side average current after the diode D7 isolation capacitance C12 filtering; This signal compares through the voltage comparator that U1A forms; Comparative result is isolated output through diode D5, after diode D4 and resistance R 19, also delivers to the error comparison point of pwm chip again through " 5 " pin.

In During normal welding process, the given potentiometer of welding current is determining the welding current size, and welding current is given to reach dynamic balance with the welding current feedback in the error comparison point of pwm chip.

when welding arc very short; When almost wanting short circuit; Arc voltage also can be very low, and this moment, integrated circuit U2B output can uprise, and the voltage of sending socket X3 back to through external potentiometer also can height; Make the output of integrated circuit U2D also have higher negative value voltage; This negative voltage is through being added on the error comparator of pwm chip through " 5 " pin after the resistance R 18, is equivalent to that extra to have increased electric current given, so just makes welding machine when welding rod short circuit soon, export bigger electric current-----be called push current.Push current can prevent to occur in the welding process phenomenon of glutinous bar, guarantees that welding process is stable smooth.The big I of push current is passed through push current potentiometer manual adjustment according to actual conditions.

are when the welding beginning, owing to not having electric current before the weldering, so the primary side current impulse amplitude is very little; Cause integrated circuit U1C output voltage very low; Through the comparison of integrated circuit U1A, can obtain the negative voltage of nearly 15V at the negative terminal of capacitor C 7, after diode D4 and resistance R 19, deliver to the error comparison point of pwm chip through " 5 " pin; Be equivalent to that extra to have increased electric current given, so just make welding machine welding during beginning the bigger electric current of output------is called the striking electric current.Along with the foundation of welding current, integrated circuit U1C can export high potential, and integrated circuit U1A also can export high potential after relatively, and the current potential of capacitor C 7 negative terminals can be along with it self slowly vanishing through the discharge of resistance R 20.The slowly vanishing of given meeting that makes welding machine export bigger electric current during beginning in welding of aforementioned extra increase, at this moment arc process finishes.The striking electric current can make the welding starting the arc easy, strengthens the arcing initiation success rate of cold workpiece cold rod.The striking size of current can be according to actual conditions through striking electric current potentiometer manual adjustment.

The implementation of abnormal protection is specially in the utility model:

overcurrent protection: overcurrent protection divides slight single pulse overcurrent protection and severe overcurrent to cut off output protection fully.

are when overcurrent is not too serious; The amplitude of primary side current pulse signal can exceed than normal burst amplitude; This signal is delivered to control circuit board through socket X7, delivers to " 13 " pin of pwm chip again, delivers to PWM integrated circuit U2 (UC3846) overcurrent pass broken ends of fractured bone 16PIN on the pwm chip through resistance R8 on the pwm chip; PWM integrated circuit U2 can stop when prepulse output immediately; Play single overcurrent protection, and next pulse output as usual, to not influence of welding process.

are when overcurrent is serious; The amplitude of primary side current pulse signal can be high more a lot of than normal burst amplitude; The base potential Ub that this signal is delivered to triode Q3 in the control circuit through socket X7 can be higher than makes triode Q3 conducting more than its emitter stage current potential 0.65V; Triode Q3 conducting makes triode Q4 and Q5 conducting again, and triode Q4 and Q5 are connected into the positive feedback form, so in case triode Q4 and Q5 conducting will be locked rapidly under conducting state.Collector voltage after the triode Q4 conducting is connected to the base stage of triode Q6 through resistance R 42; Also conducting of triode Q6; Make that through photoelectrical coupler U3 the 1PIN voltage of PWM integrated circuit U2 is zero immediately in the pwm chip circuit; Block pwm pulse fully, start is just pressed the recovery of PWM soft starting mode normally again after power cutoff is eliminated fault.

under-voltage protection: in industrial frequency rectifying filtering and power supply circuits 1, special undervoltage detection circuit is arranged; The under-voltage signal of detected electrical network passes on the diode D10 on the control circuit board through socket P8 and X9; Make that through resistance R 35 and photoelectrical coupler U3 the 1PIN voltage of PWM integrated circuit U2 is zero immediately in the pwm chip circuit; Block pwm pulse fully, when line voltage recovered normal value, PWM pressed soft starting mode and recovers normal.

overtemperature protection: socket X8 is circumscribed with temperature relay in industrial frequency rectifying filtering and power supply circuits 1, and temperature relay places on the radiator at inverter power switching device place.Make radiator temperature raise for a certain reason and surpass setting value; Temperature relay can be closed; Make that through diode D6 resistance R 35 and photoelectrical coupler U3 the 1PIN voltage of PWM integrated package U2 is zero immediately in the pwm chip circuit; Block pwm pulse fully, when radiator temperature such as having only to recover normal value, PWM press soft starting mode and recovers normally.

The implementation that welding current in the utility model shows is specially:

The given signal of electric current that are provided by external potentiometer is integrated the positive electric current that generates after the negative given signal of electric current that generates after circuit U 2C resistance R 12, R13, R14, R15 capacitor C 6 potentiometer W1, W2 etc. handle is handled through integrated circuit U1B resistance R 21, R22, R23, R24, R25, R49 potentiometer W4 capacitor C 8 etc. again and shows signal, and the digital display list of LED that is sent on the display floater by socket X1 shows welding current.

The above is merely the preferred embodiment of the utility model, not in order to restriction the utility model, any modification of being done within all spirit at the utility model and the principle, is equal to and replaces and improvement etc., all should be included within the protection domain of the utility model

Claims (7)

1. a single tube IGBT contravariant arc welder is characterized in that, comprising: main line and control circuit;

Said main line is made up of the ac input end that is linked in sequence successively through the signal of telecommunication, industrial frequency rectifying filtering and power supply circuits, medium frequency inverter circuit, intermediate frequency step-down transformer, intermediate frequency rectification circuit, intermediate frequency filtering inductance and dc output end;

Said control circuit comprises: power frequency control transformer, master control and PWM pulse-width modulation circuit and demonstration and regulating circuit;

Said industrial frequency rectifying filtering and power supply circuits also are connected with master control and PWM pulse-width modulation circuit through the power frequency control transformer;

Said medium frequency inverter circuit wherein also is provided with current sampling circuit for the bridge inverter main circuit of single tube IGBT group and symmetrical drive circuit formation, and the current feedback signal that said current sampling circuit obtains sampling is sent to master control and PWM pulse-width modulation circuit;

Be provided with voltage sampling circuit in the said dc output end, the voltage feedback signal that said voltage sampling circuit obtains sampling is sent to master control and PWM pulse-width modulation circuit;

Said master control is joined with PWM pulse-width modulation circuit and medium frequency inverter circuit, is used for driving the medium frequency inverter circuit according to the signal that receives;

Said demonstration and regulating circuit and master control and PWM pulse-width modulation circuit two-way admittance are used for showing to master control and PWM pulse-width modulation circuit input control signal and to the signal of master control and PWM pulse-width modulation circuit.

2. single tube IGBT contravariant arc welder according to claim 1; It is characterized in that said master control and PWM pulse-width modulation circuit comprise: current feedback system, striking electric current give fixed system, overcurrent protection signal system, pwm pulse power amplifying system, pwm pulse control system for fixed system, welding current for fixed system, push current.

3. single tube IGBT contravariant arc welder according to claim 2 is characterized in that said medium frequency inverter circuit comprises: four groups of switching tubes, and it is respectively: first group of switching tube, second group of switching tube, the 3rd group of switching tube, the 4th group of switching tube;

Said first group of switching tube comprises: IGBT single tube Q1a and Q1b, capacitance-resistance absorption resistance R13 and R14, capacitance-resistance absorb capacitor C 9 and C10, gate-drive resistance R 15 and R16;

Said second group of switching tube comprises: IGBT single tube Q2a and Q2b, capacitance-resistance absorption resistance R19 and R20, capacitance-resistance absorb capacitor C 11 and C12, gate-drive resistance R 17 and R18;

Said the 3rd group of switching tube comprises: IGBT single tube Q3a and Q3b, capacitance-resistance absorption resistance R11 and R12, capacitance-resistance absorb capacitor C 5 and C6, gate-drive resistance R 9 and R10;

Said the 4th group of switching tube comprises: IGBT single tube Q4a and Q4b, capacitance-resistance absorption resistance R21 and R22, capacitance-resistance absorb capacitor C 15 and C16, gate-drive resistance R 23 and R24.

4. single tube IGBT contravariant arc welder according to claim 3 is characterized in that, said first, the 4th group with the break-make of second, third group switching tube phasic difference 180 degree mutually.

5. single tube IGBT contravariant arc welder according to claim 4; It is characterized in that said industrial frequency rectifying filtering and power supply circuits comprise: current feedback system, striking electric current give fixed system, overcurrent protection signal system, pwm pulse power amplifying system, pwm pulse control system for fixed system, welding current for fixed system, push current.

6. single tube IGBT contravariant arc welder according to claim 5; It is characterized in that; Said intermediate frequency step-down transformer is by once surveying the intermediate frequency step-down transformer that winding and secondary side full-wave rectification winding and transformer core are formed; One of first side winding is refuted and is connected to inverter bridge one mid point, and the other end is then refuted and is connected to another mid point of inverter bridge, secondaryly delivers to said intermediate frequency rectification circuit.

7. single tube IGBT contravariant arc welder according to claim 6 is characterized in that, said pwm pulse control system comprises:

Integrated circuit U2, said integrated circuit U2 are used for being responsible for generation, frequency division and the misphase of pwm pulse and the output of pwm pulse;

Pwm pulse is decided hunting of frequency electric capacity and resistance, and said pwm pulse decides hunting of frequency electric capacity and resistance is made up of capacitor C 8 and resistance R 22;

Soft starting circuit, said soft starting circuit is made up of resistance R 15, R16 capacitor C 13;

Under-voltage protecting circuit, said under-voltage protecting circuit is made up of integrated circuit U1B and resistance R 18, R19 capacitor C 12 diode D4, is used to see off 16 pin that high level removes integrated circuit U2, to turn-off pwm pulse;

The sawtooth waveforms compensating circuit, said sawtooth waveforms compensating circuit is made up of integrated circuit U1C and resistance R 13, R14 capacitor C 9, C10, is used for the sawtooth signal voltage that 8 pin of integrated circuit U2 are exported is penetrated with after amplifying, and delivers to 4 pin of U2 through resistance-capacitance network;

Error ratio, amplification, integration adjustment circuit, said error ratio is, amplification, integration adjustment circuit be made up of integrated circuit U1A, be used for to signal carry out error ratio, amplification and integration adjustment;

Emitter follower circuit, said emitter follower circuit is made up of integrated circuit U1D, be used for through error ratio, amplification and the adjusted signal of integration penetrate with 5 pin of sending into integrated circuit U2 after amplifying.

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