CN109128455A - Inverter welding machine control system - Google Patents

Abstract

The present invention relates to automobile production technical field of welding equipment, disclose a kind of Inverter Welding Machine Control System, including sequentially connected power input unit, rectification circuit, inverter circuit, the major loop that transformer and secondary commutation circuit are formed, power input unit includes being spaced apart, the Inverter Welding Machine Control System further includes control module, the control module includes CPU, sensor for detecting electric leakage, buckle releaser, the buckle releaser, which is mounted on, is spaced apart inside, sensor for detecting electric leakage is mounted on the output end being spaced apart, buckle releaser is connected to CPU by control circuit of threading off, sensor for detecting electric leakage is connected to CPU by electric-leakage detection circuit, the inverter is connected to CPU by trigger circuit, trigger circuit controls turning on and off for inverter according to the instruction of CPU.The present invention carries earth leakage detection functions, is able to detect the electric leakage of complete machine exchange side, DC side and inverter side, greatly improves the reliability of complete machine.

Description

Inverter Welding Machine Control System

Technical field

The present invention relates to automobile production technical field of welding equipment, and in particular to be a kind of Inverter Welding Machine Control System.

Background technique

Currently, inverter type welder is gradually recognized by the advantage of its energy saving and good welding performance, answer It is also increasingly wider with range, it is inevitable trend instead of common power frequency welding machine, market potential is very big.

Referring to attached drawing 1, the principle of inverter type welder is that three-phase alternating current progress rectifying and wave-filtering is first become direct current, is then passed through again It crosses IGBT and is reverse into 1KHz alternating current supply welder transformer, (specific voltage has welded transformer pressure-reducing with welding procedure Close), then low-voltage DC is become by diode progress full-wave rectification, it is used for welding.

Existing welding machine mainly has the following there are many practical problems:

(1) earth leakage protective

Automobile production field welding quality is more demanding, and inverter type welder is widely used in this field.Automobile production row Sparetime university mostly uses suspension type electrical welding machine, is welded using hand-held integration soldering turret.

Referring to attached drawing 2, integrated soldering turret is to integrate welder transformer, lower pressure rectifier circuit and soldering turret, operation Soldering turret is held in the hand searching target solder joint manually and welded by personnel.Since operator directly contacts with soldering turret, and weld Pincers are constantly in active state, it is most likely that caused by occurring because of mechanical reason situations such as damage in insulation, if welding transformer Or connecting cable once has leaky that will directly jeopardize operator's safety.

Referring to attached drawing 3, common inverter type welder generallys use air switch or common electric leakage guarantor with creepage protection function It protects device to realize, their detection of electrical leakage principle is three-phase power line also cross zero sequence current mutual inductor, the leakproof the case where Under, the vector sum of three-phase current is zero, and the electric current sensed in zero sequence current mutual inductor is zero.Once there is leaky, three The vector sum of phase current is not zero, and leakage current is just sensed in zero sequence current mutual inductor, after leakage current reaches certain value Air switch is disconnected, it is ensured that safety.

Referring to attached drawing 4, common earth leakage protective device is usually to be used in conventional list/three-phase alternating current 50Hz power supply electricity consumption to set Standby, the voltage waveform of 50Hz alternating current is sine wave, and leakage current is also sine wave, the leakage current of common earth leakage protective device Detection circuit is designed according to 50Hz sine wave.

Referring to attached drawing 5-9, the major loop of inverter type welder can be divided into three parts according to waveform difference: exchange survey, DC side And inverter side, the leakage current waveform and non-sinusoidal waveform of the DC side of inverter type welder and inverter side, leakage current frequency are also not 50Hz, The specific waveform such as following figure, common earth leakage protective device cannot detect it, and common earth leakage protective device can only be to inverse Become the electric leakage that welding machine exchange is surveyed and carries out detection protection.Exchange survey and DC side due to inverter type welder be all inside controller, A possibility that leaking electricity is little, and inverter side is the position for being easiest to occur leak current fault.Common earth detector is for inverse Become for welding machine and almost performs practically no function.

(2) stray inductance

The major loop of common inverter type welder is generally connected using common copper bar, from rectification circuit, filter circuit to inversion electricity Road, entire circuit is very long, and voltage is also relatively high, and the filter capacitor of the biggish inverter type welder of power also needs many to carry out sometimes Series-parallel to use, this allows for entire major loop and becomes more tediously long.Major loop connection is longer, and equivalent stray inductance is bigger, When IGBT is in high-speed switch, very high peak voltage will be generated, IGBT over-voltage breakdown is caused to fail.The height of peak voltage Low related with the size of stray inductance, related with IGBT switching speed (the electric current rate of climb), stray inductance is bigger, peak voltage Higher, IGBT switching speed is faster, and peak voltage is higher.

This allows for common inverter type welder controller and has to the switching speed for reducing IGBT, to reduce peak voltage, really Protecting IGBT can work normally.But after IGBT switching speed reduces, the switching loss of IGBT becomes very big, the calorific value of IGBT It will become larger, the inversion efficiency of complete machine will be lower, and the reliability of IGBT can also decline.Reverse frequency is 1KHz, IGBT switch The power of complete machine can not also be sent speed slowly excessively.

(3) radiator

The type of cooling of inverter type welder nearly all uses water cooling, is comprehensively considered according to cost and heat dissipation effect, and radiator is all For aluminum, the way of aluminium radiator is using aluminium sheet as heat-radiating substrate, and punching forms water route on aluminium sheet.Due to various regions Water quality is different, and the chemical property of aluminium is again relatively more active, and there is certain temperature in when work again, using for a period of time later in radiator Inside is easy to that oxidation fouling occurs, and cooling effect decline, operating temperature can be higher after cooling effect decline, and oxidation can be tighter Weight, vicious circle ultimately cause water line block.If cannot handle in time, IGBT caused by also generating because of failure is damaged Bad failure.According to water quality and the difference of use environment, few then half a year most 2 years, the problem of water line block will occur.

(4) filter capacitor

The filter circuit of common inverter type welder generally uses electrolytic capacitor, the spy that electrolytic capacitor has capacity big, at low cost Point.Voltage after three phase rectifier is DC 530V, and the highest pressure resistance of conventional electrolysis capacitor is 450V, the electrolysis electricity of highest pressure Hold and also there was only 550V.Generally according to the voltage rating of 1.5 times of selection capacitors of virtual voltage, this just needs voltage rating >=800V Capacitor.Electrolytic capacitor can only be used in series, be used in series and cause structure more complicated, be used in series also exist and press Problem.All there is certain leakage current in electrolytic capacitor, this is determined by the characteristic of electrolytic capacitor, and the size of leakage current can reach MA (milliampere) grade.

Referring to attached drawing 10, leakage current is equivalent to the two resistance R1/R2 that connected on DC power supply, and R1/R2 pairs of resistance DC530V is divided, and as R1=R2, each ohmically voltage is equal.Since the leakage current of each electrolytic capacitor can be Difference, also difference R1 ≠ R2, ohmically partial pressure are also different for equivalent resistance.If two concatenated electrolytic capacitor leakage current differences Larger, the virtual voltage that just will appear leakage current smaller capacitive both ends is greater than rated value, and the capacitance voltage is caused to puncture.

Since the leakage current of electrolytic capacitor is bigger, internal resistance is also bigger, and high frequency response is also bad, in actual use certainly Body fever is very serious, and fever will lead to partial electrolyte liquid and gradually dry up, and capacitance will decline, and internal resistance is just after capacitance decline Can be bigger, fever is just more serious, and such vicious circle eventually leads to condenser failure.

The specified service life of general electrolytic capacitor is 2000 hours, and long-life type is 5000 hours, extra long life It is 10000 hours.It is calculated within 8 hours according to daily work, even long-life type at most uses 2 years, this is not still generating heat In the case where.Even the electrolytic capacitor service life that actual conditions are extra long lifes at most also only has 2 years, because using The influence of middle fever greatly shortens specified service life.After electrolytic capacitor uses certain service life, temperature can be higher and higher, It can very likely burst and (be generally equipped with explosion-proof valve, the excessively high explosion-proof valve of temperature can be opened), explosion-proof valve be opened, at this time inside capacitor The electrolyte of remaining will spray, and electrolyte will be sprayed onto the devices such as master control borad, IGBT, because electrolyte is conductive and corrosion Property, and be difficult to clean up, as long as the inversion welding source of capacitor explosion is almost scrapped, value is not repaired, gives company And user causes very big loss.

There are positive-negative polarities for electrolytic capacitor, during installation it must be noted that polarity, once anti-loaded will quick-fried machine.Generally speaking make It is more harm than good with electrolytic capacitor.

Summary of the invention

The purpose of the present invention is to solve the above problems, provide a kind of Inverter Welding Machine Control System, make the reliable of complete machine Property greatly improves.

The technical solution adopted by the present invention is that:

A kind of Inverter Welding Machine Control System, including sequentially connected power input unit, rectification circuit, inverter circuit, change The major loop that depressor and secondary commutation circuit are formed, power input unit include being spaced apart, and three-phase alternating current is through power input unit Input, rectified circuit become direct current, are transformed into high-frequency alternating current using inverter, through transformer pressure-reducing and secondary commutation Circuit rectifies become low-voltage DC, use for welding, characterized in that the Inverter Welding Machine Control System further includes control mould Block, the control module include CPU, sensor for detecting electric leakage, buckle releaser, and the buckle releaser, which is mounted on, is spaced apart inside, electric leakage inspection It surveys sensor and is mounted on the output end being spaced apart, buckle releaser is connected to CPU by control circuit of threading off, and sensor for detecting electric leakage passes through Electric-leakage detection circuit is connected to CPU, and the inverter is connected to CPU by trigger circuit, and trigger circuit is according to the instruction control of CPU Inverter processed turns on and off.

Further, the Inverter Welding Machine Control System further includes filter circuit, and the filter circuit is arranged in rectification circuit Between inverter circuit, the direct current after rectification is filtered, the filter circuit is connected to by voltage sampling circuit CPU。

Further, current sampling circuit and protection circuit are connected between the output end and CPU of the inverter circuit.

Further, the CPU is also connected with action input unit and movement output unit, and the action input unit includes opening Dynamic welding, ann reset and normative choice operation；The movement output unit includes Air Valve Control, welding end signal, report Alert signal operation.

Further, the control module further includes touch screen, and the touch screen is connected to CPU by communicating circuit, described CPU is also connected with memory cell.

Further, the Inverter Welding Machine Control System further includes low pressure electric unit, and the low pressure electric unit is connected to power supply Input unit provides low tension for control module.

Further, the inverter circuit is IGBT inverter circuit, and output 1KHz alternating current is supplied the transformer.

Further, the rectification circuit, filter circuit, inverter circuit connect and form an entirety on stack bus bar, described Stack bus bar includes that the folded positive electrode layer set and positive electrode layer, positive electrode layer are located in positive electrode layer, positive electrode layer and negative electrode It is equipped with interlayer insulating film between layer, is externally provided with outer insulation in stack bus bar.

Further, the secondary commutation circuit and inverter circuit are installed on a heat sink, and the radiator includes that aluminum dissipates Hot plate opens up O shape slot on aluminium radiating board, and copper tube is embedded in O-shaped slot, and the red copper is connected to cooling water unit.

Further, the filter circuit includes filter capacitor, and the filter capacitor is one layer of metal layer of setting on basement membrane, It is rolled at cylinder, be packed into aluminum hull and formed.

The beneficial effects of the present invention are:

(1) earth leakage detection functions are carried, the electric leakage of complete machine exchange side, DC side and inverter side is able to detect；

(2) stack bus bar technology is used, is connected instead of the common copper bar of major loop, reduces the stray inductance of major loop；

(3) it using the radiator of completely new technique production, contacts cooling water no longer with aluminium, avoids the oxidation of aluminium, reduce The possibility of water line block；

(4) electrolytic capacitor is not used, the dry type film capacitor smaller using leakage current, the service life is longer makes complete machine Reliability greatly improve.

Detailed description of the invention

Attached drawing 1 is existing inverter type welder schematic diagram；

Attached drawing 2 is the main circuit schematic diagram of hand-held integration soldering turret；

Attached drawing 3 is existing common earth detector schematic diagram；

Attached drawing 4 is 50Hz electric leakage waveform diagram；

Attached drawing 5 is to exchange electrical schematic of leaking hunting；

Attached drawing 6 is DC side electric leakage schematic diagram；

Attached drawing 7 is DC side electric leakage waveform diagram；

Attached drawing 8 is inverter side electric leakage schematic diagram；

Attached drawing 9 is inverter side electric leakage waveform diagram；

Attached drawing 10 is electrolytic capacitor leakage current equivalent circuit；

Attached drawing 11 is the major loop of control system of the present invention and the schematic diagram of control module；

Attached drawing 12 is full bridge inverter figure；

Attached drawing 13 is schematic diagram of the full bridge inverter at the T1 moment；

Attached drawing 14 is schematic diagram of the full bridge inverter at the T2 moment；

Attached drawing 15 is load current, voltage oscillogram；

Attached drawing 16 is adjustment inverter type welder current diagram, keeps the duty of PWM smaller；

Attached drawing 17 is adjustment inverter type welder current diagram, keeps the duty of PWM bigger；

Attached drawing 18 is earth leakage detection functions composition block diagram；

Attached drawing 19 is buckle releaser schematic view of the mounting position；

Attached drawing 20 is the working principle circuit diagram of earth leakage detection functions；

Attached drawing 21 is buckle releaser work flow diagram；

Attached drawing 22 is laminated bus bar structure figure；

Attached drawing 23 is the internal structure chart of heat-radiator plate；

Attached drawing 24 is the structural schematic diagram of thin-film capacitor；

Attached drawing 25 is the load equivalent circuit diagram of inversion welding source；

When attached drawing 26 is using full-bridge inverting, IGBT on/off time chart；

When attached drawing 27 is using full-bridge inverting, IGBT bridgc arm short relational graph；

When attached drawing 28 is using full-bridge inverting, the dead time relational graph of IGBT；

Attached drawing 29 is constant current controlling waveform diagram；

Attached drawing 30 is the single-point standard function schematic diagram of solder joint；

Attached drawing 31 is three recyclable current impulse schematic diagrames；

Attached drawing 32 is welding current circulation schematic diagram；

Attached drawing 33, which is that electric current is slow, rises/delays drop waveform diagram；

Attached drawing 34 is the waveform diagram continuously welded；

Attached drawing 35 is power distribution timing diagram；

Attached drawing 36 is input/output action signal figure；

Attached drawing 37 is program circuit schematic diagram.

Specific embodiment

It elaborates with reference to the accompanying drawing to the specific embodiment of Inverter Welding Machine Control System of the present invention.

Referring to attached drawing 11, Inverter Welding Machine Control System includes major loop and control module, control module mainly by CPU, deposit Reservoir, communicating circuit, touch screen, action input, movement output, trigger circuit, current sampling circuit, protection circuit, voltage are adopted Sample circuit, electric-leakage detection circuit, the composition such as be spaced apart de- mouth control circuit and power supply.Major loop takes off being spaced apart of mouth function by band, leaks The composition such as electro-detection sensor, rectification circuit, filter circuit, inverter circuit.

Each section is illustrated separately below:

1, CPU, memory

CPU uses SH99F100, is a double-core (enhanced 16 bit DSP and 8 MCU) chip.MCU can be used to handle Switching value, input and output and communication, and DSP need to only be absorbed in the operation of control algolithm.The framework of DSP is by three parallel meters Calculate unit (ALU, MAC, SHIFTER), two independent address generators (DAG) and a powerful program sequencer (PSQ) it forms.Computing unit provides the computing function that all processors are capable of providing, including the monocycle multiplies/adds up, position behaviour Make, shifting function etc..Double Data address generator enables a processor in one cycle from two data storage area (Data Memory and Program Memory) two data are taken out simultaneously.Program sequencer realizes the monocycle of all instructions The circulation that the non-CPU of operation, quick interrupt response and nesting intervenes.16 PWM modules, orthogonal coding interface (QEI) Production by assembly line and the inside peripheral hardware of operational amplifier (OP) as DSP core with 14, can conveniently realize a variety of industry Control algolithm.MCU core is a kind of compatible core of high speed, high efficiency 8051, under same frequency of oscillation, compared with 8051 traditional cores Piece has operation more rapidly, the more superior characteristic of performance, and resource has built-in 256 byte SRAM, external 3840 byte SRAM, 3 A 16 bit timing device and 3 external interrupts, while 2 enhanced UART are also integrated with, 1 SPI interface.

Memory use X5325, the memory is by four kinds of functions together in one: electrification reset control, WatchDog Timer, Decompression management and the serial EEPROM with block protection function.It helps to simplify the design of application system, reduces printed board Area occupied, improve reliability.Serial EEPROM in the chip is that have the block lock protection CMOS of Xicor company serial EEPROM, it is organized into 8 structures.The spi bus mode that it is made of by one four lines is operated, erase-write cycles At least 1,000,000 times, and the data finished writing can save 100 years.

2, communicating circuit, touch screen

This controller, as human-computer interaction interface, is carried out by the way of communication using touch screen between touch screen and CPU Data exchange.The serial ports of touch screen is RS485, and communicating circuit is that the serial ports of CPU is converted to RS485 electric level interface and touch screen It is attached.In order to improve anti-interference ability, communicating circuit is completed using isolation communication chip ADM2483.

For touch screen using TK6071 series, screen size is 7 inch, and rate is 800*480 respectively.Touch screen shows that picture passes through Configuration software EasyBuilder Pro is designed and produced, and multiple and different pages is divided into according to function, mainly there is key frame, specification Setting screen, parameter setting picture etc..

Communications protocol between touch screen and CPU is Modbus RTU, and touch screen actively initiates communication, CPU as host As slave, data format is 1 start bit, 8 data bit, 1 bit check position (even parity check), 1 stop position, baud rate 9600.Instruction format is as follows:

Reading instruction format:

Host computer sends instruction

Address+function code+initial address+reading word number+check code CRC16

Slave computer return instruction

Address+function code+reading byte number+reading data+check code CRC16

Write command format:

Host computer sends instruction

Address+function code+initial address+data to be written+check code CRC16

Slave computer return instruction

Address+function code+initial address+write-in data+check code CRC16

3, action input, movement output

Action input part mainly includes the signals such as starting welding, ann reset and normative choice；Act output par, c It mainly include the movements such as Air Valve Control, welding end signal, alarm signal.Input and output are all made of DC24V power supply.

4, trigger circuit

Trigger circuit controls turning on and off for IGBT according to the instruction of CPU, and can detecte the working condition of IGBT, Once it was found that IGBT operation irregularity, then notify CPU, CPU then stops working immediately, and warning message is sent to touch screen immediately It shows.

IGBT trigger circuit is verified now using 2QD0108T17 driving, which is powered using DC15V, and single channel is exportable The driving power of 1W.

5, current sample, protection circuit, voltage sample

Current sampling circuit handles the inverter output current signal that current sensor samples, and first believes exchange Number become direct current signal, and carry out hardware filtering processing, is then passed to CPU and carries out A/D conversion sampling, touching is sent to after being computed Touch screen display.

For the inverter output current signal that current sensor samples also into protection circuit, the effect of the circuit is when load Electric current is alarmed when being more than specified value, prompts user load electric current excessive.Judge whether electric current in such a way that hardware compares Excessive, CPU is differentiated by interrupt signal.CPU is considered as overcurrent phenomenon occur after detecting interrupt signal, stops immediately Work, and warning message is sent to touch screen and is shown.

Voltage sampling circuit is for detecting the DC voltage after three phase rectifier, using light-coupled isolation, the method for resistance current limliting Carry out DC voltage sampling, voltage signal is amplified by amplifier, handle after be sent to the A/D sample port of CPU, be computed After be sent to touch screen and show.

6, detection of electrical leakage, be spaced apart tripping control

Electric-leakage detection circuit handles the leakage current signal that leakage current sensor detects, now turns leakage current signal For voltage signal, ac pulse voltage signal is then converted into DC pulse voltage signal, finally enters the A/D sampling of CPU Port is shown real-time leakage current value by touch screen after CPU is calculated.

The leakage current value sampled is compared by CPU with setting value, once actual leakage current values are more than setting value, is then led to It crosses and is spaced apart tripping control circuit submitting DC24V power supply to buckle releaser, be spaced apart to thread off immediately, cuts off three-phase input power supply.

7, power supply

Power supply required for control loop is by AC380V by after transformer pressure-reducing, then passes through Switching Power Supply offer.Touching It touches after screen power supply is rectified by transformer pressure-reducing and directly provides.

8, it is spaced apart

It is spaced apart the switch as power supply of the whole machine.DC24V buckle releaser is installed, after buckle releaser connects DC24V power supply, be spaced apart by It threads off immediately.

9, rectification circuit

The rectification circuit of major loop is three-phase bridge rectification, and three-phase alternating current is become Rectified alternating current, rectifying device Stress levels are 1600V.

10, filter circuit

The filter circuit of inverter type welder generally uses capacitor filtering, and ripple current of the capacitor in addition to bearing power supply will also be held The reactive current loaded.This controller is filtered using thin-film capacitor, than electrolytic capacitor there is higher electric current to bear energy Power and better high frequency response.

11, inverter circuit

Referring to attached drawing 12 to 17, inverter circuit uses full-bridge inverting, and full bridge inverter is formed using four IGBT, and four IGBT is connected in turn in pairs, simultaneously turns in T1 moment VT1, VT4, and the both ends RL generate forward voltage, and T2 moment VT2, VT3 are simultaneously Conducting, the both ends RL generate backward voltage, are connected again in T3 moment VT1, VT4, and so on, just generate in load RL in this way The alternating current IR of certain frequency.Inverter type welder controller generally adjusts output electric current by the way of PWM, by adjusting PWM Duty ratio size, change the size of inverter output current, to change the size of welding current.

The function and feature of system are as follows:

1, earth leakage detection functions

This function samples leakage current by the way of A/D conversion, carries out calculating ratio to electric leakage signal by CPU Compared with frequency and waveform to leakage current do not require, so the electric leakage of exchange side can be detected, can also detect DC side and inversion The electric leakage of side.

(1) it forms

Referring to attached drawing 18, earth leakage detection functions are mainly by leak current detection sensor T, electric-leakage detection circuit, CPU, tripping Control circuit, buckle releaser such as are spaced apart at the composition.

(2) structure

Referring to attached drawing 19, it is spaced apart the input terminal for being mounted on complete machine three phase mains, buckle releaser, which is mounted on, is spaced apart inside, electric leakage inspection It surveys sensor T and is mounted on the output end being spaced apart.Electric-leakage detection circuit and tripping control circuit are located at mainboard.

(3) working principle

Referring to attached drawing 20, the leakage current that the working principle leak current detection sensor T of earth leakage detection functions will test is believed It number is sent to the electric-leakage detection circuit of mainboard, first leakage current signal is amplified through IC1-1, then will be handed over through IC2-1 and IC2-2 Signal pulse stream becomes DC pulse signal, and the A/D for being sent to CPU through R10 is converted, which is carried out calculation processing by CPU, and sets Definite value is compared, if practical leakage current is more than setting value, Q2 is connected by R1 in CPU, and optocoupler IC1 primary has electric current logical It crosses, IC1 grade conducting, so that Q1 be made to be connected, after Q1 conducting, relay J1 obtains electric actuation, and normally opened contact J1-1 is connected, buckle releaser DC24V power supply is connected, to make to be spaced apart tripping.

(4) work flow diagram is as shown in Fig. 21.

(5) it shows

In normal work, collected leakage current value is sent to touch screen and shown by CPU, is allowed users in real time Understanding current system insulation situation.

2, stack bus bar

The problem of for common inverter type welder controller major loop stray inductance, this controller also solved.Sampling is folded Rectification circuit, filter circuit and inverter circuit are connected into an entirety by layer busbar technology, and circuit is most short, makes major loop Stray inductance minimizes, it is ensured that the high-speed switch of IGBT.

(1) structure

Referring to attached drawing 22, first copper sheet is carried out as requested punching press, punching be made into required electrode, then by positive electrode 221 and negative electrode 222 among cover insulation film 223 after press together, it is external again with insulation film 224 close come.

(2) main feature

Stray inductance is greatly reduced, and there is very high reliability and safety；Complete machine it is simple for structure, compact； Impedance is lower；Anti-stiff installation, will not malfunction.

3, embedded water-cooled radiator

Improvement has also been made to water-cooled radiator in this controller, and rectification circuit and inverter circuit are commonly mounted on one piece of heat dissipation On device, waterway connector is placed in outside controller casing, leakage hidden trouble is not present inside controller.Radiator, which uses, inlays copper pipe The problem of as the mode of water pipe, contacting cooling water no longer with aluminium, avoiding aluminium fouling easy to oxidize, complete machine work it is reliable Property greatly improves.

(1) structure

Referring to attached drawing 23, the matrix of radiator is aluminium sheet, opens " O " type groove 232 on aluminium sheet 231 using CNC technique, passes through Great tonnage press inlays copper tube into " O " type groove 232, is then filled out using the heat-conducting glue containing metal powder to gap It fills, polishes spreader surface finally by grinding machine.It is thermally conductive in radiator and large power semiconductor device smearing when installation Rouge comes into full contact with large power semiconductor device with radiator.Cooling water flows through copper tube, by copper tube by the heat in aluminium sheet Amount is taken away.

(2) feature

It is compact integral structure, succinct.The chemical property of copper is more stable, it is not easy to react, avoid with impurities in water The problem of fouling, reduce the possibility of blocking.The heat dissipation performance of radiator will not change substantially.Integrated design reduces The possibility of leak.Guarantee is provided for the reliably working of complete machine.

4, thin-film capacitor

The filter circuit of this controller uses novel thin film capacitor, smaller than the calorific value of general electrolytic capacitor to obtain More, the service life is longer.

(1) structure

Referring to attached drawing 24, thin-film capacitor is dry-type capacitance, is that vacuum distillation technique is used above in basement membrane 241 to form one layer Very thin metal is wound into cylinder as conductive electrode 242, is then charged into aluminum hull and is made, and both ends form terminals 243.No Use aluminium foil as electrode as electrolytic capacitor.

(2) feature

Thin-film capacitor needs not distinguish between polarity, easy for installation.Insulation impedance is very high, and leakage current is small, and calorific value is low.High frequency sound Ying Hao, dielectric loss is small, and ripple current is big.Long service life is 10 times of general electrolytic capacitor or more.It is high pressure resistant, it is easy to The voltage rating for accomplishing 800V or more, without being used in series, structure is simple.

Thin-film capacitor also has certain self-healing property.Self-healing property refer to when capacitor part two layers of electrode puncture when, Metal powder around short-circuiting percentage can be short-circuited heat of vaporization brought by electric current, restore insulation.Theoretically, thin-film capacitor The problem of there is no short-circuit failures.

(3) major function

1, constant current controlling

(1) control mode:

Constant current controlling is divided to primary constant current and two kinds of secondary constant-current, control principle be it is identical, only sample mode is different, Primary Constant flow sample and setting are welding transformer primary currents, and what secondary constant-current was sampled and set is time of welding transformer Grade electric current.Turn-on time (duty ratio) by changing inversion circuit IGBT controls the welding current of transformer output.

(2) control principle:

Welding current required for user is arranged by touch screen and weld interval, required welding current are setting Value, CPU detect that current value is actual current value by sample circuit, and actual current value is compared by CPU with setting value, such as Fruit actual current value is less than setting value, and CPU will be issued and be instructed the duty ratio for increasing IGBT, increases actual current value；Such as fruit Border current value is greater than the set value, and CPU will be issued and be instructed the duty ratio for reducing IGBT, reduces actual current value.

(3) circuit characteristic:

Referring to attached drawing 25, the load of inversion welding source is welding transformer, is equivalent to R, L series circuit, the electricity above R There are certain phase differences with voltage for stream.

Referring to attached drawing 26,27,28, the major loop of inverter type welder uses full-bridge inverting, two VT1, VT4 and VT2, VT3 bridges Arm is connected in turn, and when VT1, VT4 are opened, VT2, VT3 shutdown, when VT2, VT3 are opened, VT1, VT4 shutdown will not theoretically be deposited In the VT1 and VT3 or VT2 and VT4 possibility opened simultaneously, but lag and IGBT miller capacitance due to actual drive circuits Influence, IGBT needs regular hour Ton, Toff in on/off, is possible to will appear so in actual operation The situation that of short duration VT1 and VT3 or VT2 and VT4 are opened simultaneously, the case where causing power supply short circuit.So when two bridge arms are turning It when changing it has to be ensured that after VT1, VT4 closing, and to be delayed after a period of time, VT2, VT3 could be opened, it is ensured that inverse Become system worked well, a period of time that be equally also delayed after VT2, VT3 closing could open VT1, VT4, be delayed Time is referred to as dead time, is in off state in 4 IGBT of dead time, and the afterflow in L forms circuit by VD and C. Dead time cannot be arranged it is excessive, it is excessive, the service time of IGBT in whole cycle can be reduced, influence whole system most Big output power is generally the 2-4us after IGBT is thoroughly turned off, it can be ensured that inversion circuit is not in short under the frequency of 1KHz The case where road.General switch time Ton, the Toff for only considering IGBT of the setting of dead time, the switch time of IGBT and driving Voltage, driving resistance and inherent parameters are related, unrelated with load variation.

(4) controlling difficulties:

The characteristics of electric resistance welding is high current, short time, and the workpiece welded in this way will not deform, change colour, welding efficiency Also high, it is fast that this requires the welding current rates of climb, and control precision wants high, and the consistency welded every time will be got well.Common control PID control is usually used in method processed, and the rate of climb of electric current is slow, and entire weld interval becomes very long, and workpiece is easy to become Shape, discoloration, working efficiency are also very low.Welding current is preferably risen into required value with most fast speed, and is stablized Near setting value.

(5) control method:

The cycle time T of 1KHz is 1ms, after starting welding, so that IGBT is opened half period T/2's in a cycle 20%, about 100us (ignores dead time), while carrying out the continuous sampling of n times point to output electric current, according to when previous sampling Electric current is compared with a preceding sample rate current, calculates the climbing speed of electric current, that is, the slope that electric current rises in the following figure. In addition to the climbing to electric current calculates, root-mean-square value calculating also is carried out to the N point electric current sampled, obtains welding current Virtual value Irms, calculation formula are as follows:

N: sampling number, I1, I2, In: the current value sampled every time.

Referring to attached drawing 29, the required IGBT when actual current value is equal with setting value is predicted according to calculated result and is opened It the logical time, is calculated as the service time of second round IGBT, then to the electric current that second period samples, to first The current-rising-rate that period calculates is modified, while again by actual current value compared with setting value progress again, obtaining third The service time of a period IGBT, then calculated, compared, predicted, successively fourth, fifth N number of period, welded up to when secondary Binding beam.

2, a variety of welding conditions storages and calling

User at most can the storage of preset 32 kinds of welding conditions in memory, to adapt to different welding process requirements.Often A specification shares 17 each parameters, is respectively as follows: squeeze time, pressing time, pre- thermocurrent, preheating time, interval, slow liter, welding Electric current, weld interval, interval, slow drop, temper current, tempering time, hold time, the stop time, pressurization delay, when being pressurized Between.User can carry out Selection and call specification by 5 binary codes, can form automation control with industrial control equipments such as PLC System carries out selection welding conditions by equipment such as PLC.

Standard parameter table

Specification is called " 1 " to represent and is connected, and " 0 ", which represents, to be disconnected.

3, single-point standardizes more

When a certain workpiece needs to weld multiple solder joints, because there is shunting and bond pad locations different problems, each solder joint The welding current needed may be different, if being very cumbersome using the method that one solder joint of every weldering manually changes welding current , efficiency is very low.It can effective solution this problem using the more standard functions of single-point.Passed through in advance according to different solder joints different Specification presets different welding current and weld interval, and different solder joints is welded according to certain sequence, and program will automatically switch not Same welding conditions are welded.

Referring to attached drawing 30, needing to weld for example, workpiece shares 5 solder joints, each solder joint needs electric current respectively different, wherein No. 1 solder joint needs electric current minimum, and electric current is incremented by successively, sets 5 for generic specification number, specification 1-5 is respectively set to required weldering Electric current is connect, by automatic welding 1-5 point after starting welding, for No. 1 solder joint using No. 1 specification, No. 2 solder joints use No. 2 specifications class according to this It pushes away, after No. 5 solder joint welding, stops working, waiting is again started up welding.

4, multiple weld pulses

Referring to attached drawing 31,32, the welding current of settable three sections of different times, respectively " pre- thermoelectricity in primary welding Stream ", " welding current ", " temper current ", wherein " welding current " and " interval " can also recycle, cycle-index is at most settable 99 times.

5, the slow liter of electric current/slow drop

The surface of some workpiece may have certain greasy dirt or machined burrs, exist and contact bad phenomenon, if The case where directly being welded using welding current and be easy to appear splashing, splashing will will lead to welding quality decline.Need elder generation Burr or greasy dirt are burnt up with lesser electric current, high current welding again after workpiece contacts well with electrode uses electric current is slow to rise function It can effectively prevent spatter phenomenon.

Referring to Figure 33, some workpiece do not allow welding current to interrupt suddenly after the completion of welding, otherwise it is possible that weldering Situations such as point cracking, the slow drop function of electric current can make welding current uniform descent, to meet welding procedure demand.

The electric current slow time for rising/delaying drop can be configured according to demand, generally several cycles to more than ten of cycle.

6, tally function

Butt welding contact number is counted, and can select to be shown by " counter/routine " key, can by this function User is facilitated to understand production capacity, in adjustment state without counting.

7, work/setting state

There are two types of working conditions for setting, are " work " and " setting " respectively." work " state refers to that controller has been ready for At, starting welding instruction can be received at any time is welded, this state not modifiable parameter." setting " state refers to parameter setting shape State allows to modify each standard parameter and functional parameter in this state, cannot start welding, even if receiving starting welding instruction CPU It does not respond yet.

" work " state and " setting " state are indicated by indicator light respectively, are cut by " work/setting " key It changes.It not can be switched in the welding process.

8, adjustment/bond pattern

There are two types of operating modes for controller tool, are " adjustment " and " welding " respectively.In " adjustment " mode, welding is only executed Process and movement, do not export welding current, for using when debugging machine." welding " mode is normal bond pattern.

9, single spot welding/series spot welding

Referring to attached drawing 34, can select to be single spot welding or series spot welding according to welding workpiece difference, single spot welding is every It welds and instructs to one-shot, welding is a bit.Series spot welding is to weld to instruct to one-shot, continuous to weld N point, until receiving It is instructed to welding is stopped.

10, power distribution

Referring to attached drawing 35, function can be used when user there are more welding machine work, but electrical network capacity does not allow to weld simultaneously Rate distribution function, the function can make each welding machine carry out timesharing welding, and reasonable utilization power network resources avoid more welding machines simultaneously Accident is overloaded caused by welding.This function need to be used cooperatively with power divider.

11, fault diagnosis

When detecting system exception, CPU stops work at present immediately, and the fault message that will test is sent to touch Screen display, is prompted to user by display window, and user is facilitated to understand in time and handling failure.

12, input/output acts

Referring to attached drawing 36, input action has enabling signal, normative choice signal, heat portective switch signal etc., and CPU is according to connecing The unlike signal received makes corresponding instruction.Output action has Air Valve Control signal, welding end signal etc., and CPU is according to work Make situation and sends corresponding output action signal.

(4) software section

1, program circuit

Referring to attached drawing 37, CPU judges current state after booting, if it is in setting state, then waits user setting parameter, If waiting enabling signal in working condition, after detecting enabling signal, precompressed is successively executed according to the parameter of specification setting The processes such as time, pressing time, after standard parameter is finished, counter adds a counting, judges whether it is sequential welding It connects, is welded if it is single, then power cut-off is waited for.If it is continuous welding, and halt instruction is not received, It is then executed since the pressing time of Current specifications, otherwise power cut-off enters wait state.

2, process is illustrated

(1) it is switched on

Power on, CPU passes through hardware reset, then carries out self-test and executes initialization program, each from memory calls Parameter, then normal display, booting are completed.

(2) judge work/setting state

After the completion of booting, CPU starts to read the state for preservation of shutting down, and goes to if being " work " state before shutdown " work " state then goes to " setting " state before shutdown for " setting " state.

(3) state is set

In " setting " state, user's setting or modification parameter are waited.This state even if having starting welding signal not It responds.It needs artificially to switch to " work " state by " work/setting " key after parameter setting.

(4) working condition

In " work " state, CPU detects starting welding signal, if once detecting starting welding signal, Welding is started according to specification setting parameter immediately.All parameters are locked in this state, any parameter cannot be modified.

(5) welding conditions are executed

CPU starts to execute corresponding welding variables after detecting enabling signal, is squeeze time first, followed by adds Press the parameters such as time, preheating time, interval.

(6) it counts

After welding variables is finished, counter adds one, completes primary welding.If reported in the welding process Situations such as alert or midway artificially terminates, it is not abnormal to currently once welding, without counting.

(7) single/continuous

Parameter " single/continuous " is judged after the completion of counting, welds, is stopped working into waiting if it is single State.If it is in continuous state, then having continued to determine whether that terminating welding instructs, if being also not over welding instruction, Be transferred to continuous welded condition, executed since " pressing time " of Current specifications, skip for the first time welding when execute " when precompressed Between ".If detecting end welding instruction, stop working, into wait state.

3, program

This program is programmed using C language, and most commonly used in program to be logical construction and judge sentence, there are also sequence knots Structure, FOR type loop structure etc..The part DSP is mainly responsible for A/D sampling, calculating and IGBT triggering control, MCU and is mainly responsible for display And communication.Mainly there are following sections:

(1) opening initialization program；

(2) memory read/write program；

(3) A/D sampling and calculating；

(4) IGBT trigger；

(5) it shows；

(6) data exchange of MCU and DSP；

(7) fault detection；

(8) RS485 is communicated.

The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art Member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications also should be regarded as Protection scope of the present invention.

Claims (10)

1. a kind of Inverter Welding Machine Control System, including sequentially connected power input unit, rectification circuit, inverter circuit, transformation The major loop that device and secondary commutation circuit are formed, power input unit include being spaced apart, and three-phase alternating current is defeated through power input unit Enter, rectified circuit becomes direct current, is transformed into high-frequency alternating current using inverter, through transformer pressure-reducing and secondary commutation electricity Road rectification becomes low-voltage DC, uses for welding, it is characterised in that: the Inverter Welding Machine Control System further includes control mould Block, the control module include CPU, sensor for detecting electric leakage, buckle releaser, and the buckle releaser, which is mounted on, is spaced apart inside, electric leakage inspection It surveys sensor and is mounted on the output end being spaced apart, buckle releaser is connected to CPU by control circuit of threading off, and sensor for detecting electric leakage passes through Electric-leakage detection circuit is connected to CPU, and the inverter is connected to CPU by trigger circuit, and trigger circuit is according to the instruction control of CPU Inverter processed turns on and off.

2. Inverter Welding Machine Control System according to claim 1, it is characterised in that: the Inverter Welding Machine Control System also wraps Filter circuit is included, the filter circuit is arranged between rectification circuit and inverter circuit, is filtered to the direct current after rectification, The filter circuit is connected to CPU by voltage sampling circuit.

3. Inverter Welding Machine Control System according to claim 1, it is characterised in that: the inverter circuit output end with Current sampling circuit and protection circuit are connected between CPU.

4. Inverter Welding Machine Control System according to claim 1, it is characterised in that: the CPU is also connected with action input list Member and movement output unit, the action input unit include starting welding, ann reset and normative choice operation；It is described dynamic It include Air Valve Control, welding end signal, alarm signal operation as output unit.

5. Inverter Welding Machine Control System according to any one of claim 1 to 4, it is characterised in that: the control module It further include touch screen, the touch screen is connected to CPU by communicating circuit, and the CPU is also connected with memory cell.

6. Inverter Welding Machine Control System according to any one of claim 1 to 4, it is characterised in that: the inverter type welder Control system further includes low pressure electric unit, and the low pressure electric unit is connected to power input unit, provides low pressure for control module Electricity.

7. Inverter Welding Machine Control System according to any one of claim 1 to 4, it is characterised in that: the inverter circuit For IGBT inverter circuit, output 1KHz alternating current is supplied into the transformer.

8. Inverter Welding Machine Control System according to any one of claim 2 to 4, it is characterised in that: the rectification circuit, Form an entirety on filter circuit, inverter circuit connection stack bus bar, the stack bus bar include the folded positive electrode layer set and Positive electrode layer, positive electrode layer are located in positive electrode layer, and interlayer insulating film is equipped between positive electrode layer and positive electrode layer, in lamination mother It is exclusive to be equipped with outer insulation.

9. Inverter Welding Machine Control System according to any one of claim 2 to 4, it is characterised in that: the secondary commutation Circuit and inverter circuit are installed on a heat sink, and the radiator includes aluminium radiating board, and O shape is opened up on aluminium radiating board Slot, is embedded copper tube in O-shaped slot, and the red copper is connected to cooling water unit.

10. Inverter Welding Machine Control System according to any one of claim 2 to 4, it is characterised in that: the filter circuit Including filter capacitor, the filter capacitor is one layer of metal layer of setting on basement membrane, rolled at cylinder, is packed into aluminum hull shape At.