CN207508489U

CN207508489U - Digitlization variable polarity welding power supply based on SiC IGBT

Info

Publication number: CN207508489U
Application number: CN201721635787.4U
Authority: CN
Inventors: 王振民; 韦俊好; 吴健文
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2017-11-30
Filing date: 2017-11-30
Publication date: 2018-06-19
Anticipated expiration: 2027-11-30

Abstract

The utility model provides a kind of digitlization variable polarity welding power supply based on SiC IGBT, it is characterised in that：Including main circuit and control circuit；Main circuit includes sequentially connected three phase rectifier filter circuit, inverter circuit of SiC IGBT, high frequency transformer, SiC hyperfrequency rectifying and wave-filterings output circuit, SiC IGBT secondary inverter circuits and high pressure arc static circuit；Control circuit includes controller and controls power supply module and inversion drive module of digitizing tablet, SiC and SiC secondary inverting drive modules for being connect respectively with controller signals；Digitizing tablet, inversion drive module of SiC and SiC secondary invertings drive module are electrically connected respectively with control power supply module；Inversion drive module of SiC is also connect with inverter circuit of SiC IGBT；SiC secondary invertings drive module is also connect with SiC IGBT secondary inverter circuits.The variable polarity welding power supply is easy to resume combustion after can making arc extinction, small, high conversion efficiency, reliable and stable work.

Description

Digitlization variable polarity welding power supply based on SiC IGBT

Technical field

The utility model is related to source of welding current technical field, more specifically to a kind of number based on SiC IGBT Change variable polarity welding power supply.

Background technology

Variable polarity welding power supply be initially Nasa be develop space shuttle and utility model development one kind it is novel The source of welding current is now widely used in the industry manufacture fields such as aerospace, automobile, train, ship.Aluminium, magnesium and its alloy tool There is the advantages that density is small, and specific stiffness is high, and electromagnetic shielding capability is strong, energy conservation and environmental protection, extensively should in more than industry manufacture field With variable polarity welding power supply has deoxidation film in the welding of magnalium and its alloy, and agitation molten pool, stomata is few, reduces tungsten The many merits such as pole scaling loss and welding arc stablility, it is with the obvious advantage in a variety of welding methods, it is magnalium and its alloy welding Ideal source.

At this stage, there are still problems, critical issue to be in welding process for variable polarity welding power supply both domestic and external, becomes The problem of polarity moment arc extinction is restriked.Therefore, the emphasis that the arc static circuit of welding power supply secondary inversion is studied into people. At present, there are two types of most common secondary inverting stabilising arc methods.One kind is full bridge structure circuit topology stabilising arc strategy, using " common Conducting " or the method for " common cut-off ", make output inductor and capacitor charge and discharge, and one is provided to electric arc in electric current commutation moment A high-voltage pulse can ignite again immediately after making arc extinction.But this method is only applicable to the situation of small current welding, big electricity When fluid welding connects, excessively high stabilising arc pulse voltage can cause the IGBT punch through damage of secondary inverting, this method restricted application, and It needs to simultaneously turn on 2 in 4 IGBT, total switching loss is big, and system is numerous and jumbled, of high cost.Another kind is half-bridge structure circuit Topological stabilising arc strategy, what the electric current in the output inductor of the secondary inverter circuit always reduced in polarity process, in this way The speed that current direction switches when having slowed down power supply Variable Polarity is unfavorable for the stabilization of electric arc.

Utility model content

The purpose of the utility model is to overcome shortcoming and deficiency of the prior art, provide it is a kind of based on SiCIGBT, can Solve the problems, such as that Variable Polarity moment arc extinction restrikes, is small, the digitlization Variable Polarity of high conversion efficiency, reliable and stable work is welded Connect power supply.

In order to achieve the above object, the utility model is achieved by following technical proposals：It is a kind of based on SiCIGBT's Digitize variable polarity welding power supply, it is characterised in that：Including main circuit and control circuit；The main circuit includes sequentially connected Three phase rectifier filter circuit, inverter circuit of SiC IGBT, high frequency transformer, SiC hyperfrequency rectifying and wave-filterings output circuit, SiC IGBT secondary inverter circuits and high pressure arc static circuit；Wherein, three phase rectifier filter circuit is connect with three-phase alternating-current supply, high Arc static circuit is pressed to be connected with load；

The control circuit includes controller and controls power supply module and the digital face being connect respectively with controller signals Plate, inversion drive module of SiC and SiC secondary inverting drive modules；The digitizing tablet, SiC inversion drive module It is electrically connected respectively with control power supply module with SiC secondary invertings drive module；Described inversion drive module of SiC also with SiC Inverter circuit connection of IGBT；The SiC secondary invertings drive module is also connect with SiC IGBT secondary inverter circuits.

It is smooth direct current electricity that three phase rectifier filter circuit, which is used for three-phase alternating current rectifying and wave-filtering,；Inversion of SiC IGBT Circuit is used to direct current being modulated into the high-frequency ac square wave of high voltage, low current；Before high frequency transformer is used for isolating transformer Circuit and modulate the high-frequency ac square wave of low-voltage, high current afterwards；SiC hyperfrequency rectifying and wave-filterings output circuit is used for high frequency Ac square wave rectifying and wave-filtering is into direct current；SiC IGBT secondary inverter circuits are electric for converting the output of SiC hyperfrequencies rectifying and wave-filtering The polarity of the direct current of road output welds required Variable Polarity electric current to be formed；High pressure arc static circuit is used for welding current Variable Polarity When for arc space provide a high back voltage, reliably ignite again after ensureing current zero-crossing point moment arc extinction；SiC is once inverse Become drive module and be used to drive in main circuit opening and turning off for SiC IGBT in an inverter circuit, realize constant current or constant pressure control System；SiC secondary invertings drive module is used to drive in main circuit opening and turning off for SiC IGBT in secondary inverter circuit, realizes Current polarity changes.

The power device of the utility model variable polarity welding power supply uses a new generation SiC IGBT so that and switching speed is fast, Switching loss is few, and a reverse frequency is up to more than 93% up to more than 100kHz, the transfer efficiency of power supply, and Energy Efficiency Ratio is existing The IGBT sources of welding current energy saving 10% or so；Simultaneously as the significantly promotion of reverse frequency, high frequency transformer and each filtering device It can be used compared with ting model, power supply overall volume becomes smaller, light-weight；By reasonably setting positive value pulse current and negative value electric current Size and duty ratio, the heat input of welding arc can be precisely controlled, it is easy in welding process to avoid magnesium, aluminium and its alloy The problems such as molten bath of appearance stays, deforms, burning, spatter.Static high back voltage arc static circuit is added in main circuit, is accelerated Electrode conversion speed；Before current polarity switching, superimposed pulse stabilising arc electric current increases arc space degree of ionization, after making arc extinction It is more easy to ignite.

Preferably, the three phase rectifier filter circuit includes three phase rectifier module BR101 and the LC filter module being connected； Described inverter circuit of SiC IGBT includes SiC IGBT module TR101, SiC IGBT modules TR102 and RC and absorbs protection electricity Road；The SiC hyperfrequencies rectifying and wave-filtering output circuit includes SiC diode D101, SiC diode D102, SiC diodes D103, SiC diode D104 and filter protective circuit；SiC diode D102 and SiC diodes D104 series connection after be parallel to by On the series circuit of SiC diode D101 and SiC diodes D103 compositions；The SiC IGBT secondary inverter circuits include SiCIGBT module TR103, SiC IGBT modules TR104 and RCD absorb protection circuit；The high pressure arc static circuit includes two poles Pipe D105, diode D108, cast ceramic resistor R117, output inductor L102 and high-frequency coupling inductance T102；

The SiC IGBT modules TR101 and SiC IGBT module TR102 is parallel to respectively on LC filter modules；High frequency becomes The primary of depressor is connect respectively with SiC IGBT module TR101 and SiC IGBT modules TR102, the secondary output of high frequency transformer End one is connect with SiC diode D101 and SiC diode D103 tie points, the secondary output end three and SiC bis- of high frequency transformer Pole pipe D102 is connected with SiC diode D104 tie points；

SiC IGBT module TR103 and SiC IGBT modules TR104 is parallel to respectively by SiC diodes D101 and SiC bis- On the series circuit of pole pipe D103 compositions；The SiC IGBT modules TR103 also passes through sequentially connected diode D105, two poles Pipe D108, cast ceramic resistor R117 and output inductor L102 are connect with high-frequency coupling inductance T102；High frequency transformer Secondary output end two is connect with cast ceramic resistor R117 and output inductor L102 tie points；The SiC IGBT modules TR103 is connect with the anode loaded；High-frequency coupling inductance T102 is connect with the cathode loaded；Cast ceramic resistor R117 and output Output bypass filter circuit is also associated between filter inductance L102 tie points and the anode of load；

SiC IGBT module TR101 and SiC IGBT modules TR102 is connect respectively with inversion drive module of SiC；SiC IGBT module TR103 and SiC IGBT module TR104 is connect respectively with SiC secondary inverting drive modules.

The utility model digitlization variable polarity welding power supply operation principle be：Three-phase alternating-current supply is filtered by three phase rectifier Wave circuit forms direct current, and the high current low-voltage that more than 100kHz high frequencies are converted by inverter circuit of SiC IGBT is handed over Square wave is flowed, by SiC hyperfrequency current rectifying and wave filtering circuit rectifying and wave-filterings into direct current, high frequency transformer is by high-frequency and high-voltage ac square wave The ac square wave of high frequency high current is converted into, most switches the transmission direction of smooth direct current electricity through SiCIGBT secondary inverter circuits afterwards, Achieve the purpose that electric current Variable Polarity；High pressure arc static circuit makes pottery High Level AC Voltage rectifying and wave-filtering generation high voltage direct current by cast Porcelain resistor loaded in the cathode of load, electric current from forward direction turn to negative sense when, give arc space one high back voltage, play stabilising arc Effect, the high pressure arc static circuit can avoid introducing high pressure, High-frequency Interference, ensure the reliability of power supply；Therefore the utility model Variable polarity welding power supply can reach arc stability, and nearly zero splashes, the technological effect of high quality weld seam.

Preferably, described inversion drive module of SiC is included by resistance R201, resistance R202, P-channel power field effect The push-pull output circuit one of pipe M201 and N-channel power field effect pipe M202 compositions, by resistance 203, resistance R204, P-channel work( The push-pull output circuit two and high-frequency pulse transformer that rate field-effect tube M203 and N-channel power field effect pipe 204 form T201, high-frequency pulse transformer T202 and four road drive signal generation circuits.

Preferably, the SiC secondary invertings drive module includes optocoupler U301, optocoupler U302, zener diode D301, steady Press diode D302, gate driving resistance R302, gate driving resistance R305, varistor R303 and varistor R306.

Preferably, the control power supply module includes sequentially connected filtering surge limiting unit, rectification filtering unit, anti- Exciting converter and several Voltage stabilizing modules and the driving unit being connect with flyback converter.

Preferably, PID adjusting completion constant current output controls are carried out for sampling the welding current of output and feeding back to controller The current feedback module of system；

The voltage completed constant pressure output and controlled is adjusted for sampling the weldingvoltage exported and feeding back to controller progress PID Feedback module；

For the switching value module for the switching signal that o controller generates；

Circuit is protected for carrying out the abnormality detection that monitoring in real time judges and protected to the working condition of the source of welding current；

The digitizing tablet is connected by CAN communication Interface and Controler, for completing welding parameter setting, welding current The real-time display of voltage；

The current feedback module, voltage feedback module, switching value module are connect respectively with controller；Controller is used for root The Current Voltage value provided according to the welding parameter of digitizing tablet setting with current feedback module and voltage feedback module is compared To generate digital PWM signal.

Preferably, the abnormality detection protection circuit includes current foldback circuit, under-voltage overvoltage crowbar.

Preferably, the current foldback circuit includes rectifier D401, rectifier D402, rectifier D403, rectifier D404, resistance R401, capacitance C401, comparator U401, high speed photo coupling U402, optocoupler U403 and optocoupler U404.

Preferably, the under-voltage overvoltage crowbar is included by divider resistance R501, divider resistance R502, divider resistance The bleeder circuit and comparator U501 of R503 and divider resistance R504 compositions.

Preferably, the controller includes the high-performance DSC microprocessors based on ARM Cortex-M4 kernels.

Compared with prior art, the utility model has the following advantages that and advantageous effect：

1st, source of welding current performance is good, safe：The utility model uses the high-performance based on ARM Cortex-M4 kernels DSC microprocessors, equipped with dedicated DSP instructions and FPU Float Point Unit (FPU), data processing speed is up to 210DMIPS, Complete machine has superior dynamic characteristic, the segmentation classification Fine design that can realize welding arc and control in real time, to welding electricity Source realtime monitoring and feedback；

2nd, capacity usage ratio higher, energy conservation and environmental protection, technological effect are good：All power devices of the utility model use new one For SiC IGBT so that switching speed is fast, and switching loss is few, and a reverse frequency is imitated up to more than 100kHz, the conversion of power supply Rate is up to more than 93%, the existing IGBT sources of welding current energy saving 10% or so of Energy Efficiency Ratio；Simultaneously as reverse frequency is significantly It is promoted, high frequency transformer can be used with each filtering device compared with ting model, and power supply overall volume becomes smaller, light-weight；By reasonable Setting positive value pulse current and negative value electric current size and duty ratio, the heat input of welding arc can be precisely controlled, kept away Exempted from magnesium, aluminium and its alloy stay, deform in the molten bath that welding process easily occurs, burning, spatter the problems such as；

3rd, arc stability is good：Static high back voltage arc static circuit is added in main circuit, accelerates electrode conversion speed；Electric current Before polarity switching, superimposed pulse stabilising arc electric current increases arc space degree of ionization, is more easy to ignite after making arc extinction；It can not only use In Welded, moreover it can be used to the high-performance welding of a variety of alloy materials such as titanium alloy, magnesium alloy；

4th, reliability higher：The power device of the utility model is a new generation SiC IGBT, than common IGBT power devices With better heat tolerance, pressure-resistant performance and high frequency tolerant, High-current output is adapted to, can be used for small current welding. Under higher working frequency, higher power dissipation generates more self-heatings, leads to higher working junction temperature (225 DEG C or so), SiC The power handling capability and switching frequency capability of IGBT is improved.Forbidden band range is wide, and there is no reversely extensive for devices switch process Multiple effect, reliability are easier to be protected.

Description of the drawings

Fig. 1 is the structure diagram of the utility model variable polarity welding power supply；

Fig. 2 is the equivalent topologies figure of the main circuit of the utility model variable polarity welding power supply；

Fig. 3 is inversion drive module structure diagram of SiC of the utility model variable polarity welding power supply；

Fig. 4 is the SiC secondary inverting drive module structure diagrams of the utility model variable polarity welding power supply；

Fig. 5 is the structure diagram of the control power supply module of the utility model variable polarity welding power supply；

Fig. 6 is the structure diagram of the current foldback circuit of the utility model variable polarity welding power supply；

Fig. 7 is the structure diagram of the under-voltage overvoltage crowbar of the utility model variable polarity welding power supply；

Fig. 8 is the structure diagram of the digitizing tablet of the utility model variable polarity welding power supply；

Fig. 9 is the electrical block diagram of the controller of the utility model variable polarity welding power supply.

Specific embodiment

The utility model is described in further detail with specific embodiment below in conjunction with the accompanying drawings.

Embodiment

As shown in Figures 1 to 9, digitlization variable polarity welding power supply of the present embodiment based on SiC IGBT, including main circuit With control circuit；Main circuit includes sequentially connected three phase rectifier filter circuit, inverter circuit of SiC IGBT, high frequency transformation Device, SiC hyperfrequency rectifying and wave-filterings output circuit, SiC IGBT secondary inverter circuits and high pressure arc static circuit；Wherein, three phase rectifier Filter circuit is connect with three-phase alternating-current supply, and high pressure arc static circuit is connected with load；

Control circuit include controller and control power supply module and connect respectively with controller signals digitizing tablet, Inversion drive module of SiC and SiC secondary inverting drive modules；Digitizing tablet, inversion drive module of SiC and SiC bis- Secondary inversion drive module is electrically connected respectively with control power supply module；Inversion drive module of SiC is also once inverse with SiC IGBT Become circuit connection；SiC secondary invertings drive module is also connect with SiCIGBT secondary inverter circuits.

Preferable scheme is that：Control circuit further includes：It is carried out for sampling the welding current of output and feeding back to controller PID adjusts the current feedback module for completing constant current output control；For sample output weldingvoltage and feed back to controller into Row PID adjusts the voltage feedback module for completing constant pressure output control；For the switching value for the switching signal that o controller generates Module；Circuit is protected for carrying out the abnormality detection that monitoring in real time judges and protected to the working condition of the source of welding current；Number Literal plate is connected by CAN communication Interface and Controler, and for completing welding parameter setting, the real-time of welding current voltage is shown Show；Current feedback module, voltage feedback module, switching value module are connect respectively with controller；Controller is used for according to digital face The Current Voltage value that the welding parameter of plate setting is provided with current feedback module and voltage feedback module is compared to generate number Word pwm signal.

The utility model variable polarity welding power supply can be used for the welding of DC constant voltage characteristic, can be used for pulse, double Variable Polarity pulse TIG or the MIG welding of the random waveforms such as pulse, intermediate value pulse.

The concrete structure of main circuit is：Three phase rectifier filter circuit includes the three phase rectifier module BR101 and LC that are connected Filter module；Inverter circuit of SiC IGBT includes SiC IGBT module TR101, SiCIGBT modules TR102 and RC and absorbs guarantor Protection circuit；SiC hyperfrequency rectifying and wave-filterings output circuit includes SiC diode D101, SiC diode D102, SiC diodes D103, SiC diode D104 and filter protective circuit；SiC diode D102 and SiC diodes D104 series connection after be parallel to by On the series circuit of SiC diode D101 and SiC diodes D103 compositions；SiC IGBT secondary inverter circuits include SiC IGBT Module TR103, SiC IGBT module TR104 and RCD absorb protection circuit；High pressure arc static circuit includes diode D105, two poles Pipe D108, cast ceramic resistor R117, output inductor L102 and high-frequency coupling inductance T102；

SiC IGBT module TR101 and SiC IGBT modules TR102 is parallel to respectively on LC filter modules；High frequency transformer Primary connect respectively with SiC IGBT module TR101 and SiC IGBT modules TR102, the secondary output end one of high frequency transformer It is connect with SiC diode D101 and SiC diode D103 tie points, secondary output end three and the SiC diodes of high frequency transformer D102 with SiC diode D104 tie points connect；

SiC IGBT module TR103 and SiC IGBT modules TR104 is parallel to respectively by SiC diodes D101 and SiC bis- On the series circuit of pole pipe D103 compositions；SiC IGBT modules TR103 also passes through sequentially connected diode D105, diode D108, cast ceramic resistor R117 and output inductor L102 are connect with high-frequency coupling inductance T102；Time of high frequency transformer Grade output terminal two is connect with cast ceramic resistor R117 and output inductor L102 tie points；SiC IGBT modules TR103 with The anode connection of load；High-frequency coupling inductance T102 is connect with the cathode loaded；Cast ceramic resistor R117 and output filtered electrical Output bypass filter circuit is also associated between sense L102 tie points and the anode of load；Output bypass filter circuit includes resistance R115, capacitance C113, capacitance C114 and capacitance C116；

The operation principle of main circuit is：Three-phase alternating current forms direct current by three phase rectifier filter circuit, passes through SiC Inverter circuit of IGBT is converted into the high current low-voltage AC square wave of more than 100kHz high frequencies, by SiC hyperfrequency rectifications High-frequency and high-voltage ac square wave is converted into the exchange side of high frequency high current by filter circuit rectifying and wave-filtering into direct current, high frequency transformer Wave, the transmission direction most afterwards through SiC IGBT secondary inverter circuits switching smooth direct current electricity, achievees the purpose that electric current Variable Polarity；When When welding current is positive, the anode Q105 and Q106 of SiC IGBT module TR103 and SiC IGBT modules TR104 is open-minded, SiC The negative terminal Q107 and Q108 of IGBT module TR103 and SiC IGBT module TR104 is disconnected, and flows through cast ceramics power resistor R117 Electric current be zero, stabilising arc high pressure does not work to arc space at this time；Electric current switchs to the moment of negative sense, SiC IGBT moulds from forward direction The anode Q105 and Q106 of block TR103 and SiC IGBT module TR104 is disconnected, SiC IGBT module TR103 and SiC IGBT moulds The negative terminal Q107 and Q108 of block TR104 is open-minded, arc extinction, and power supply is zero load, and high pressure arc static circuit forming circuit is made With giving arc space one high-voltage pulse, electric arc promoted to ignite again；After electric arc ignites again, cast ceramics power resistor R117 is by arc short circuit, and the electric current for flowing through cast ceramics power resistor R117 is almost nil, and stabilising arc high pressure does not play arc space Effect.High Level AC Voltage rectifying and wave-filtering generation high voltage direct current is loaded on load by high pressure arc static circuit by cast ceramic resistor Cathode, electric current from forward direction turn to negative sense when, give arc space one high back voltage, play the role of stabilising arc.

Scheme still more preferably is：Main circuit is further included by rectification module B101, resistance R116 and capacitance C115 groups Into RC rectification output filter circuits；Input terminal connection three-phase/single phase alternating current power supply of rectification module B101.

Controller includes the high-performance DSC microprocessors based on ARM Cortex-M4 kernels；Such as DSC grades of 168M works The ARM chips STM32F405RGT6 of working frequency.Controller further includes the low pressure being made of AMS1117 (U2) and its peripheral circuit Poor linear stabilized power supply module, the outer clock circuit being made of Y1, C1~C2 and R1 are answered by the outside that S1, C1, R7 are formed Position and is made of circuit R2-R5, R8 and CN1 JTAG debugging circuit formed etc..DSC microprocessors can be opened according to power Close pipe work schedule and logical relation generate multichannel pulsewidth, duty ratio, dead time and phase can soft readjustment number Word pwm signal；DSC microprocessors have embedded corresponding current-voltage double-closed-loop control algorithm, can realize constant pressure, constant current, change The functions such as slope characteristics and multi-ladder Characteristics Control, more segmentation energy holes and Variable Polarity control.

The concrete structure of inversion drive module of SiC is：Including being imitated by resistance R201, resistance R202, P-channel power field Should pipe M201 and N-channel power field effect pipe M202 composition push-pull output circuit one, by resistance 203, resistance R204, P-channel The push-pull output circuit two and high-frequency pulse transformer that power field effect pipe M203 and N-channel power field effect pipe 204 form T201, high-frequency pulse transformer T202 and four road drive signal generation circuits.Due to inverter circuit power device of SiC IGBT The operating current of part is all smaller, and working frequency is higher, therefore inversion drive module of SiC uses high-frequency pulse transformer Isolated form driving circuit.The PWM drive signal of TTL types produed by the controller, is isolated by high-speed linear optocoupler It is separately input to P-channel power field effect pipe M201, N-channel power field effect pipe 202, P-channel power field effect pipe later M203 and N-channel power field effect pipe 204, output signal are put respectively using high-frequency pulse transformer T201 and T202 Four road IGBT drive signals are generated after big and isolation, corresponding SiC IGBT modules are driven.

The concrete structure of SiC secondary inverting drive modules is：Including optocoupler U301, optocoupler U302, zener diode D301, Zener diode D302, gate driving resistance R302, gate driving resistance R305, varistor R303 and varistor R306. SiC secondary invertings drive module uses optical coupler isolating type driving circuit.The PWM drive signal of TTL types produed by the controller, warp It crosses after high speed linear optical coupling device is isolated and is separately input to optocoupler U130, U302, generate the pwm signal of two-way complementation, The SiC IGBT modules of the double half-bridge SiC IGBT secondary inverter circuits of driving.Wherein, zener diode D301, D302 is closed in IGBT Back bias voltage during disconnected state is provided, ensures quick, the reliable turn-off of SiC IGBT modules.Varistor R303, R306 are interference Due to voltage spikes provides bypass channel, and reliably protecting is carried out to SiC IGBT modules.

Controlling the concrete structure of power supply module is：Including sequentially connected filtering surge limiting unit, rectification filtering unit, Flyback converter and several Voltage stabilizing modules and the driving unit being connect with flyback converter.Control power supply module can be very That stablizes in wide change range of input voltage realizes the direct current output of two-way+12V, two-way -12V and three tunnel+5V, and net is pressed The adaptability of fluctuation is good, further improves the reliability of control system.

Preferable scheme is that：Abnormality detection protection circuit includes current foldback circuit, under-voltage overvoltage crowbar.

Current foldback circuit include rectifier D401, rectifier D402, rectifier D403, rectifier D404, resistance R401, Capacitance C401, comparator U401, high speed photo coupling U402, optocoupler U403 and optocoupler U404.Current foldback circuit passes through AC mutual induction Coil carries out contactless detection to high frequency transformer primary current and samples, and according to 200A:The CTR current transfer ratio of 1A, will be big Electric current is converted to low current signal, after rectification circuit and sampling resistor R402, is converted to proportional d. c. voltage signal V_f, it is input to comparator U401 inverting inputs, and V_refFor reference voltage, when over-current phenomenon avoidance occurs, V_f＞ V_ref, comparator U401 exports low level, and optocoupler U403 and optocoupler U404 is caused to form latching circuit, while high speed photo coupling U402 output high level, Overcurrent protection signal transmission is generated to controller, performs corresponding protection act, over current fault LED light D405 is lighted, table IGBT over-current phenomenon avoidances have occurred in the bright source of welding current.

Under-voltage overvoltage crowbar is included by divider resistance R501, divider resistance R502, divider resistance R503 and partial pressure electricity Hinder the bleeder circuit and comparator U501 of R504 compositions.V_OCIt is straight after transformer pressure-reducing, rectifying and wave-filtering for network voltage Sampled voltage is flowed, different voltage is reduced to by the resistance pressure-dividing network being made of divider resistance R501~R504 in proportion After value, reverse phase, the in-phase input end of two comparator U501 are separately input into, with reference voltage V_refIt is compared, when resistance point Pressure value is more than V_refWhen, comparator U501 output low level signals, then it is assumed that over-voltage fault occurs at this time；When the resistance of another way Less than V_refWhen, another way comparator U501 output high level signals, it is believed that under-voltage fault occurs at this time, the fault indication signal It is transmitted to chip interior, triggering welding gun shutdown, so as to fulfill the protection of the source of welding current.

Digitizing tablet can be the panel or industrial control touch screen system of charactron+digital keys pattern.This It is introduced based on the man-machine interaction panel for sentencing charactron+digital keys pattern.Mainly include DSC minimum systems, feedback electricity The compositions such as road, orthogonal encoder, button, LED charactrons, driving circuit, LED light；Button, LED and charactron and DSC are most The GPIO modules of mini system are connected, and LED and Nixie tube drive circuit are using 74HC595 and ULN2003 extension I/O ports and amplification The electric current of LED and charactron ensure enough display brightness；The digitizing tablet completes welding parameter setting, welding current voltage Real-time acquisition testing and display and by CAN BUS networks and the source of welding current etc. carry out information data share with number control System.

The basic principle of the utility model innovative design is：Using based on all-digitized demodulator technology and high-power SiCIGBT High frequency switching inverter technology builds the high performance digital variable polarity welding power supply with high pressure stabilising arc function；Utilize digitizing tablet Accurate human-computer interaction is realized by CAN communication interface.On this basis, using a variety of current-voltage waveform precision control plans It omits, the superimposed pulse electric current output needed for accurate control welding arc heat input and stabilising arc, weight small so as to be made to Amount is light, arc stability, and weldquality is good and energy-saving and environment-friendly variable polarity welding power supply.

The operation principle of the utility model is：Three-phase alternating current forms direct current through full-bridge rectifier filter, passes through SiC Inverter circuit of IGBT is converted into the high current low-voltage AC square wave of more than 100KHz high frequencies, by SiC hyperfrequency rectifications Filter circuit rectifying and wave-filtering most carries out the conversion of current polarity, output becomes through SiC IGBT secondary inverter circuits afterwards into direct current The welding current of polarity；Current feedback module and voltage feedback module are mainly used for detecting the current value of source of welding current output in real time And voltage value, and it is supplied to controller；Digitizing tablet mainly realize the default of technological parameter, state the human-computer interactions work(such as display Energy；The Current Voltage value that controller is mainly provided according to the preset value of digitizing tablet and current feedback module and voltage feedback module Suitable digital PWM signal is generated by pid algorithm, and passes through inversion drive module of SiC, SiC secondary invertings driving mould Block changes the PWM analog drive signals of suitable SiC IGBT modules into, realizes hyperfrequency driving modulation, obtains required precision current Voltage waveform；High pressure arc static circuit loads on High Level AC Voltage rectifying and wave-filtering generation high voltage direct current by cast ceramic resistor The cathode of output terminal, electric current from forward direction turn to negative sense when, give arc space one high back voltage, play the role of stabilising arc；Pass through Above work, the utility model variable polarity welding power supply can accurately control welding arc heat input, reach arc stability, closely Zero splashes, the technological effect of high quality weld seam.

Above-described embodiment is the preferable embodiment of the utility model, but the embodiment of the utility model is not by above-mentioned The limitation of embodiment, the change made under other any Spirit Essences and principle without departing from the utility model are modified, are replaced In generation, simplifies combination, should be equivalent substitute mode, is included within the scope of protection of the utility model.

Claims

1. a kind of digitlization variable polarity welding power supply based on SiC IGBT, it is characterised in that：Including main circuit and control circuit； The main circuit includes sequentially connected three phase rectifier filter circuit, SiC IGBT inverter circuit, high frequency transformer, a SiC Hyperfrequency rectifying and wave-filtering output circuit, SiC IGBT secondary inverter circuits and high pressure arc static circuit；Wherein, three phase rectifier filtered electrical Road is connect with three-phase alternating-current supply, and high pressure arc static circuit is connected with load；

The control circuit include controller and control power supply module and connect respectively with controller signals digitizing tablet, Inversion drive module of SiC and SiC secondary inverting drive modules；The digitizing tablet, inversion drive module of SiC and SiC secondary invertings drive module is electrically connected respectively with control power supply module；Described inversion drive module of SiC also with SiC Inverter circuit connection of IGBT；The SiC secondary invertings drive module is also connect with SiC IGBT secondary inverter circuits.

2. the digitlization variable polarity welding power supply according to claim 1 based on SiC IGBT, it is characterised in that：Described three Commutating phase filter circuit includes three phase rectifier module BR101 and the LC filter module being connected；Inversion of SiC IGBT Circuit includes SiC IGBT module TR101, SiC IGBT modules TR102 and RC and absorbs protection circuit；The SiC hyperfrequencies rectification It filters output circuit and includes SiC diodes D101, SiC diode D102, SiC diode D103, SiC diode D104 and filtering Protect circuit；It is parallel to after SiC diode D102 and SiC diodes D104 series connection by SiC diode D101 and SiC diodes On the series circuit of D103 compositions；The SiC IGBT secondary inverter circuits include SiCIGBT module TR103, SiC IGBT moulds Block TR104 and RCD absorb protection circuit；The high pressure arc static circuit includes diode D105, diode D108, cast ceramic electrical Hinder R117, output inductor L102 and high-frequency coupling inductance T102；

The SiC IGBT modules TR101 and SiC IGBT module TR102 is parallel to respectively on LC filter modules；High frequency transformer Primary connect respectively with SiC IGBT module TR101 and SiC IGBT modules TR102, the secondary output end one of high frequency transformer It is connect with SiC diode D101 and SiC diode D103 tie points, secondary output end three and the SiC diodes of high frequency transformer D102 with SiC diode D104 tie points connect；

SiC IGBT module TR103 and SiC IGBT modules TR104 is parallel to respectively by SiC diode D101 and SiC diodes On the series circuit of D103 compositions；The SiC IGBT modules TR103 also passes through sequentially connected diode D105, diode D108, cast ceramic resistor R117 and output inductor L102 are connect with high-frequency coupling inductance T102；Time of high frequency transformer Grade output terminal two is connect with cast ceramic resistor R117 and output inductor L102 tie points；The SiC IGBT modules TR103 is connect with the anode loaded；High-frequency coupling inductance T102 is connect with the cathode loaded；Cast ceramic resistor R117 and output Output bypass filter circuit is also associated between filter inductance L102 tie points and the anode of load；

3. the digitlization variable polarity welding power supply according to claim 1 based on SiC IGBT, it is characterised in that：It is described Inversion drive module of SiC is included by resistance R201, resistance R202, P-channel power field effect pipe M201 and N-channel power field The push-pull output circuit one of effect pipe M202 compositions, by resistance 203, resistance R204, P-channel power field effect pipe M203 and N ditch The push-pull output circuit two and high-frequency pulse transformer T201, high-frequency pulse transformer that road power field effect pipe 204 forms T202 and four road drive signal generation circuits.

4. the digitlization variable polarity welding power supply according to claim 1 based on SiC IGBT, it is characterised in that：It is described SiC secondary invertings drive module includes optocoupler U301, optocoupler U302, zener diode D301, zener diode D302, grid and drives Dynamic resistance R302, gate driving resistance R305, varistor R303 and varistor R306.

5. the digitlization variable polarity welding power supply according to claim 1 based on SiC IGBT, it is characterised in that：The control Power supply module processed includes sequentially connected filtering surge limiting unit, rectification filtering unit, flyback converter and several voltage stabilizing moulds Block and the driving unit being connect with flyback converter.

6. the digitlization variable polarity welding power supply according to any one of claim 1 to 5 based on SiC IGBT, feature It is：The control circuit further includes：

For sample output welding current and feed back to controller carry out PID adjust complete constant current output control current feedback Module；

The Voltage Feedback completed constant pressure output and controlled is adjusted for sampling the weldingvoltage exported and feeding back to controller progress PID Module；

The digitizing tablet is connected by CAN communication Interface and Controler, for completing welding parameter setting, welding current voltage Real-time display；

The current feedback module, voltage feedback module, switching value module are connect respectively with controller；Controller is used for according to number The Current Voltage value that the welding parameter of literal plate setting is provided with current feedback module and voltage feedback module is compared to produce Raw digital PWM signal.

7. the digitlization variable polarity welding power supply according to claim 6 based on SiC IGBT, it is characterised in that：It is described different Often detection protection circuit includes current foldback circuit, under-voltage overvoltage crowbar.

8. the digitlization variable polarity welding power supply according to claim 7 based on SiC IGBT, it is characterised in that：The mistake Stream protection circuit include rectifier D401, rectifier D402, rectifier D403, rectifier D404, resistance R401, capacitance C401, Comparator U401, high speed photo coupling U402, optocoupler U403 and optocoupler U404.

9. the digitlization variable polarity welding power supply according to claim 7 based on SiC IGBT, it is characterised in that：It is described to owe Voltage protection circuit is pressed through to include being made of divider resistance R501, divider resistance R502, divider resistance R503 and divider resistance R504 Bleeder circuit and comparator U501.

10. the digitlization variable polarity welding power supply according to any one of claim 1 to 5 based on SiC IGBT, special Sign is：The controller includes the high-performance DSC microprocessors based on ARM Cortex-M4 kernels.