CN110620511B - Pulse current output device and output control method - Google Patents
Pulse current output device and output control method Download PDFInfo
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- CN110620511B CN110620511B CN201910837384.5A CN201910837384A CN110620511B CN 110620511 B CN110620511 B CN 110620511B CN 201910837384 A CN201910837384 A CN 201910837384A CN 110620511 B CN110620511 B CN 110620511B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/09—Arrangements or circuits for arc welding with pulsed current or voltage
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/09—Arrangements or circuits for arc welding with pulsed current or voltage
- B23K9/091—Arrangements or circuits for arc welding with pulsed current or voltage characterised by the circuits
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/16—Arc welding or cutting making use of shielding gas
- B23K9/173—Arc welding or cutting making use of shielding gas and of a consumable electrode
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
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Abstract
The invention discloses a pulse current output device which comprises a front-end rectifying and filtering circuit, an inverter, a transformer and a rear-end rectifying and filtering circuit, wherein an alternating current input value is input into the input end of the front-end rectifying and filtering circuit, the output end of the rectifying and filtering circuit is connected with the input end of the inverter, the output end of the inverter is connected with the input end of the transformer, and the output end of the transformer outputs pulse current after being rectified and filtered by the rear-end rectifying and filtering circuit. The invention has the advantages that: the current output device is simple in structure and accurate in control, can output double-pulse current required by aluminum alloy welding, and can conveniently and quickly adjust the output current through the DSP main control module so as to meet the requirement of double-pulse MIG welding.
Description
Technical Field
The invention relates to the field of vehicle welding, in particular to a pulse current output device and an output control method.
Background
The automobile manufacturing process is complex, although the traditional processing method is mature, the automobile body structure is complex in parts, the manufacturing process is long, the process equipment is complex, the production energy consumption is high, and the automobile body structure is an industrial common problem.
Aluminum frame body technology for automobiles, particularly new energy automobiles, can overcome these limitations of conventional steel body manufacturing. The automobile with the aluminum frame body needs special processes of part forming, body framework welding, outer cover piece injection molding and spraying, whole automobile general assembly detection and road test, compared with the traditional processing method, the improvement point is that the automobile body part forming is adopted, the whole automobile assembly detection and the road test pass through 5 typical processes, and the processes of inner chamber and outer cover piece assembly, chassis assembly, static debugging, whole automobile chassis detection and dynamic road test are adopted; compared with the traditional automobile manufacturing process, the method has the advantages that 2 processes are omitted in the molding of automobile body parts, 6 processes are omitted in the coating process, the manufacturing process is greatly reduced, the weight of the automobile body parts with the same size is reduced by 40%, the energy consumption is reduced to 20%, and the raw material consumption is reduced by more than 30%.
The main welding methods commonly used for connecting the aluminum frame of the new energy automobile at present comprise: alternating current tungsten argon arc welding (TIG) and metal-arc gas welding (MIG). In TIG welding, because of adopting alternating current, the burning loss of a tungsten electrode is serious, the used welding current is limited, the penetration capability is weak, and the TIG welding is only suitable for welding thin aluminum alloy. MIG welding includes continuous current welding and pulsed current welding. During MIG welding, the welding wire is used as the anode, and the welding current is higher than that of TIG welding, so that the arc power is high, the welding efficiency is high, and the welding wire is particularly suitable for welding medium-thickness plate aluminum alloy. During MIG welding of aluminum alloy, pulse current welding is superior to continuous current welding, and this raises the strength, plasticity and fatigue life of the welded aluminum alloy.
In order to further improve the stability of electric arc, improve weld forming and increase the penetration and the high-efficiency welding of thick plate aluminum alloy, double-pulse MIG welding is adopted. The double-pulse MIG welding is a fusion welding method with high welding quality, can weld thick plates and thin plates, has low heat input of parent metal and small welding deformation, and can generate beautiful and high-quality fish scale-pattern welding seams. The double pulses are widely applied to surface welding seams, have good gap bridging capacity, and can be used for all steel and aluminum materials. The heat input changes caused by the double-pulse arc can form a consistent fish-scale-like weld surface. The ability to bridge the gap is also significantly enhanced. Compared with the traditional aluminum alloy welding method, the double-pulse MIG welding can accelerate the welding speed and improve the production efficiency of products, but the energy input of the double-pulse MIG welding needs to be controlled in the process, if the energy control is inaccurate, the aluminum alloy welding forming is influenced, and the product requirement is difficult to achieve.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a pulse current output device and an output control method, which are used for conveniently outputting the current required by welding through a pulse current output device and simultaneously controlling the output of the pulse current to control the energy input in the welding process so as to meet the welding requirement and prevent welding deformation.
In order to achieve the purpose, the invention adopts the technical scheme that: the output device of the pulse current comprises a front-end rectifying and filtering circuit, an inverter, a transformer and a rear-end rectifying and filtering circuit, wherein the input end of the front-end rectifying and filtering circuit is used for inputting alternating current, the output end of the rectifying and filtering circuit is connected with the input end of the inverter, the output end of the inverter is connected with the input end of the transformer, and the output end of the transformer outputs the pulse current after being rectified and filtered by the rear-end rectifying and filtering circuit.
The output device comprises a main control chip, wherein the output end of the main control chip outputs a pulse modulation signal to the inverter for controlling the conduction and the duty ratio of a transistor in the inverter.
The input end of the main control chip is respectively connected with a current acquisition module and a voltage acquisition module, the voltage acquisition module is used for acquiring the output voltage of the rear-end rectifying and filtering circuit, and the current acquisition module is used for acquiring the current signal of the output end of the transformer and the output current signal of the rear-end rectifying and filtering circuit.
The front-end rectifying and filtering circuit comprises a rectifier and a direct current filter, alternating current is input to the input end of the rectifier and converted into direct current to be output to the direct current filter, and the output end of the direct current filter is connected with the input end of the inverter.
The rear-end rectifying and filtering circuit comprises a diode full-wave rectifying circuit and a filter reactor, wherein the input end of the diode full-wave rectifying circuit is connected with the output end of the transformer, and the output end of the diode full-wave rectifying circuit outputs pulse current through the filter reactor.
A pulse current output control method comprises the following steps
S1: converting industrial alternating current into direct current through rectification;
s2: filtering out alternating current components in the direct current;
s3: controlling an inverter to invert the filtered direct current into intermediate-frequency alternating current through a pulse modulation signal;
s4: converting the medium-frequency alternating current into low-voltage large-current alternating current;
s5: and rectifying and filtering the low-voltage large-current alternating current to convert the low-voltage large-current alternating current into low-voltage large-current pulse direct current.
And the high-current pulse direct current output by the step S5 is used for supplying power for aluminum alloy welding.
The parameters of the inverter are controlled through the pulse modulation signals to control the rear end rectifying and filtering circuit to output double-pulse current, and the average current during welding is controlled through controlling the number of pulses of pulse groups in the double-pulse current.
The duty ratio and the frequency of the inverter are controlled by controlling the pulse modulation signal to reduce the number of pulses of the low-energy pulse group in the double-pulse current.
The ratio of the number of strong current pulses to the number of weak current pulses in a unit period is changed by controlling the conduction of the inverter to control the heat input during welding.
The invention has the advantages that: the current output device has a simple structure and accurate control, can output double-pulse current required by aluminum alloy welding, and can conveniently and quickly adjust the output current through the DSP main control module so as to meet the requirement of double-pulse MIG welding; meanwhile, the duty ratio of the inverter can be controlled and adjusted through the DSP, so that the number of strong and weak pulses in the output double-pulse current is reduced, the heat input in the MIG welding process is adjusted and controlled, the energy input is reduced, the welding deformation is prevented, the welding seam quality is improved, and the double-pulse current with high quality and accurate and convenient output control is provided for the double-pulse MIG.
Drawings
The contents of the expressions in the various figures of the present specification and the labels in the figures are briefly described as follows:
FIG. 1 is a schematic diagram of a current converting apparatus according to the present invention;
FIG. 2 is a pin diagram of the DSP controller of the present invention;
FIG. 3a is a schematic representation of the corresponding DP-MIWG weld at an average current of 88A.
FIG. 3b is a schematic representation of the corresponding DP-MIWG weld at an average current of 80A.
FIG. 4a shows the corresponding DP-MIWW current waveform at average current 88A.
FIG. 4b shows the corresponding DP-MIWW current waveform at average current 80A.
FIG. 5a is a schematic representation of the corresponding TP-MIWG weld at an average current of 88A.
FIG. 5b is a schematic representation of the corresponding TP-MIWG weld at an average current of 80A.
FIG. 6a is a diagram illustrating the corresponding TP-MIWW current waveform at average current 88A.
FIG. 6b is a diagram illustrating the corresponding TP-MIWW current waveform at average current 80A.
FIG. 7a shows a gold phase diagram of DP-MIWW at average current 88A.
FIG. 7b is a schematic gold phase diagram of DP-MIWW at average current 80A.
FIG. 8A is a schematic gold phase diagram of the corresponding TP-MIWW at an average current of 88A.
FIG. 8b is a schematic gold phase diagram of the corresponding TP-MIWW at an average current of 80A.
Detailed Description
The following description of preferred embodiments of the invention will be made in further detail with reference to the accompanying drawings.
As shown in fig. 1, an output device of a pulse current includes a front-end rectifying and filtering circuit, an inverter, a transformer, a rear-end rectifying and filtering circuit, an input end of the front-end rectifying and filtering circuit is inputted with an alternating current input value, an output end of the rectifying and filtering circuit is connected with an input end of the inverter, an output end of the inverter is connected with an input end of the transformer, and an output end of the transformer outputs a pulse current after being rectified and filtered by the rear-end rectifying and filtering circuit.
The output device comprises a main control chip, the main control chip adopts a TMS320F2808 type DSP chip, and the output end of the main control chip outputs a pulse modulation signal to the inverter for controlling the conduction or non-conduction and the duty ratio of a transistor in the inverter. The input end of the main control chip is respectively connected with the current acquisition module and the voltage acquisition module, the voltage acquisition module is used for acquiring the output voltage of the rear-end rectifying and filtering circuit, and the current acquisition module is used for acquiring the current signal of the output end of the transformer and the output current signal of the rear-end rectifying and filtering circuit.
The front-end rectifying and filtering circuit comprises a rectifier and a direct current filter, wherein alternating current is input to the input end of the rectifier and is converted into direct current to be output to the direct current filter, and the output end of the direct current filter is connected with the input end of the inverter.
The rear-end rectifying and filtering circuit comprises a diode full-wave rectifying circuit and a filter reactor, wherein the input end of the diode full-wave rectifying circuit is connected with the output end of the transformer, and the output end of the diode full-wave rectifying circuit outputs pulse current through the filter reactor.
As shown in fig. 1, the overall structure of the hardware circuit is that 380V industrial electricity is rectified, filtered and converted by a three-phase bridge rectifier, a dc filter is used to filter out ac components in the dc, the filtered dc is led to an IGBT full bridge inverter circuit to invert the dc into 20kHz intermediate frequency ac, and then an intermediate frequency transformer is used to convert the 20kHz intermediate frequency ac into low voltage large current electric energy. And performing rectification and filtering again on low-voltage large current by using a fast diode full-wave rectification and output reactor, finally converting the low-voltage large current into low-voltage large current direct current for output, and controlling the driving, current feedback and voltage feedback of the circuit by using the TMS320F2808 as a main control chip.
Fig. 2 is a schematic diagram of a DSP control core. Besides VDD, AVDD, signal ground and power ground, 8 PWM ports, 8A/D input ports, 13 GPIOs, an SCI serial port, an SPI interface, a CAN bus port, a JTAG interface and the like are led out from the system.
The hardware system of the aluminum alloy sheet pulse MIG welding power supply lays a hardware foundation for realizing low input energy control of the aluminum alloy sheet pulse MIG welding. The DSP outputs a control signal to control the inverter in a mode of pulse modulation signals, so that the control of a current output device is realized by interference, and the output current is conveniently adjusted to meet the control of MIG welding on low-heat input.
A method for outputting pulse current comprises the following steps:
s01: converting the alternating current into direct current;
s02: filtering out alternating current components in the direct current;
s03: inverting the filtered direct current into intermediate frequency alternating current;
s04: converting the medium-frequency alternating current into low-voltage large-current alternating current;
s05: and rectifying and filtering the low-voltage large-current alternating current to convert the low-voltage large-current alternating current into low-voltage large-current pulse direct current.
Preferably, the alternating current in step S01 is 380V industrial electricity.
Preferably, in step S01: the alternating current is converted into direct current through a three-phase bridge rectifier.
Preferably, in step S02: and filtering out alternating current components in the direct current by using a direct current filter.
Preferably, in step S03: the filtered direct current is inverted into intermediate frequency alternating current through an inverter.
Preferably, in step S04: the medium-frequency alternating current is converted into low-voltage large-current alternating current through a transformer.
Preferably, in step S05: and performing rectification filtering again on the low-voltage large-current alternating current by utilizing a fast diode full-wave rectification and output reactor, and converting the low-voltage large-current alternating current into low-voltage large-current direct current.
Preferably, the method is used for outputting the aluminum alloy welding pulse current.
In addition, the invention also provides a current conversion device, which comprises a rectifier, a filter, an inverter and a transformer, wherein the current conversion device is used for realizing the method in any one of the invention.
In addition, the invention also provides a double-pulse MIG welding method, wherein the current adopted by welding is the pulse current output by any one of the output methods, the output pulse current is specifically the double-pulse current, and the average current during welding is reduced by reducing the number of pulses of the low-energy pulse group in the double-pulse current.
Preferably, the welding method is applied to welding of aluminum alloy materials.
Preferably, the welding method is applied to welding of the aluminum alloy frame of the new energy automobile.
The invention realizes the conversion from the industrial alternating current to the pulse direct current through the current conversion device, controls the heat input by changing the number of the pulses of the aluminum alloy welding strength, ensures the steady state performance of the pulse welding current under the condition of ensuring the stable forming of the welding seam under the given welding parameters, reduces the energy input, prevents the welding deformation, improves the forming quality of the welding seam, and reduces the welding cost of the aluminum alloy frame of the new energy automobile.
The parameters of the inverter are controlled through the pulse modulation signals to control the rear end rectifying and filtering circuit to output double-pulse current, and the average current during welding is controlled through controlling the number of pulses of pulse groups in the double-pulse current. The duty ratio of the inverter is controlled by controlling the pulse modulation signal to reduce the number of pulses of the low-energy pulse group in the double-pulse current. The pulse number of the pulse group with low energy in the pulse current is reduced, so that the heat input in the welding process is reduced, the welding requirement is met, and a better current signal is provided to meet the quality of a welding seam. The duty ratio of the inverter is controlled by adjusting a modulation signal output by the DSP, so that the current output is controlled to meet the requirement of reducing the number of low-energy group pulses, the control parameter for controlling the reduction of the number of the low-energy group pulses by the DSP output needs to be calibrated according to a plurality of tests, the specific control number needs to be obtained through a process evaluation test, the process evaluation can be carried out on a plurality of working conditions, the number of pulses in each working condition is determined, a process database is formed, the process database is directly called later, and the output of the corresponding double-pulse current is controlled according to the DSP output parameter corresponding to the tool database.
The invention realizes the conversion of industrial alternating current to pulse direct current, preferably the conversion of double-pulse direct current, through the current conversion device, the converted double-pulse direct current is used for the double-pulse MIG welding of the aluminum alloy framework of the new energy automobile, the heat input is controlled by changing the number of strong and weak pulses, the energy input can be effectively reduced, the welding deformation is prevented, the welding seam forming quality is improved, and the aluminum alloy of the new energy automobile is reduced
As shown in fig. 1, in order to realize square wave output of the aluminum alloy welding pulse current and meet the large current required by welding, a full-bridge inverter circuit phase-shifted full-bridge topology is selected. The basic working process of the circuit is as follows: the industrial electricity 380V/50Hz is firstly converted into direct current through a three-phase bridge rectifier, alternating current components in the direct current are filtered out by a direct current filter, the filtered direct current is led into a high-power inverter, the direct current is inverted into intermediate frequency alternating current of 20kHz, and then the intermediate frequency alternating current of 20kHz is converted into low-voltage large-current electric energy by an intermediate frequency transformer. And performing rectification and filtering again on the low-voltage large current by using a fast diode full-wave rectification and output reactor, and finally converting the low-voltage large current into low-voltage large current direct current for output.
In order to realize stable welding of the double-pulse MIG welding of the aluminum alloy, current waveform parameters need to be flexibly controlled, and the double-pulse MIG welding method is adopted to control the influence of heat input on the microstructure structure and the mechanical property of a welding joint by changing the ratio of the number of strong current pulses to the number of weak current pulses in a unit period under the condition of keeping the low-frequency unchanged. The pulse output device can be controlled, and only the output control parameters of the DSP are required to be controlled.
To verify the effectiveness of controlling the number of pulses in controlling the current output by the DSP as described herein for weld quality. A wavelet analyzer was used to collect the current waveform during the welding process. The wavelet analyzer utilizes wavelet algorithm to filter the collected current signal, and then transmits the anti-electromagnetic interference signal through the shielded coaxial cable, and finally outputs a stable and reliable oscillogram and related evaluation data, thereby providing evaluation basis for the stability of the welding process.
The new energy automobile aluminum alloy frame welding process based on heat input control comprises the following steps:
the aluminum alloy sheet material has the characteristics of low melting point, high thermal conductivity, high porosity, easy oxidation, soft material and the like, so that the defects of penetration, undercut, pores, inclusion, cracks and the like can be greatly shown in the welding process, and the defects are caused by overhigh welding input energy. The influence on the low input energy of the aluminum alloy sheet pulse MIG welding is mainly researched by changing the number of strong and weak pulses.
Part of the arc energy in welding is transferred to the base metal, and part of the arc energy is converted into heat energy to melt the welding wire and the workpiece. The total power P ═ IU of the arc is expressed, and due to partial heat loss in the total power, the effective power P λ ═ λ P ═ λ IU in practical situations occurs, and λ is an effective power factor, and according to a table look-up, the effective power factor range of the pulse MIGW is 0.70-0.80, which is 0.70 in the present text. If the current is to be reduced, the number of pulses is to be reduced, while the base time is gradually increased while maintaining the same frequency and the same welding speed. As can be seen from the equation q ═ P λ/v for the input energy, the heat input decreases as the current decreases and the effective power decreases, while maintaining the constant speed.
Due to the characteristic that the aluminum alloy is extremely easy to be oxidized, after the aluminum alloy is carefully cleaned, welding must be carried out within 2-3 h, so that the phenomena of oxidation aggravation and moisture absorption are avoided, and the sensitivity of air holes is increased. The passive film on the surface of the aluminum alloy can be damaged by the welding slag remained on the welding seam and the vicinity of the welding seam after welding, so the aluminum alloy is washed in hot water by using the hard bristles and is finally naturally dried. The performance of the aluminum alloy is active, H2, N2 and O2 are not suitable to be used as protective gas, and in addition, the aluminum alloy sheet is welded, and the protective gas is required to play a certain shielding role on a base metal and a welding wire, so that the inert gas of 99.99% pure argon is used in the test, and the gas flow is 15L/min. On the premise of welding speed of 0.6m/min and the same current, two groups of tests are designed by using DP-MIWW and TP-MIWW respectively for comparative analysis, and other parameters are shown in tables 1 and 2, wherein the table 1 is DP-MIWW comparative test data under different pulse numbers of a low-energy pulse group, and the table 2 is shown. Fig. 3a,3b, 5a,5b are graphs of the welding joints corresponding to different average currents under the control of two waveforms, and fig. 4a,4b, 6a,6b are graphs of their respective corresponding waveforms.
TABLE 1
TABLE 2
As can be seen from fig. 4a,4b, 6a,6b, reducing the number of pulses of the low energy pulse train effectively reduces the average current of DP-MIGW and TP-MIGW, both with an input energy reduction of about 14%, while maintaining the high energy pulse train parameters and the welding speed constant. The welds in FIGS. 3a,3b, 5a,5b were all well formed, but the TP-MIWG was more uniform than the DP-MIWG weld.
7a,7b, 8a,8b are the corresponding gold phase diagrams of the welding joint of DP-MIWW, TP-MIWW under different average currents, the grain growth phenomenon of two groups of fig. 7a, 8a is more serious than that of the corresponding fig. 7b, 8b, and the number of second phase points is less than that of the latter, which microscopically shows that the grain growth and the less second phase points are caused by high input energy, so the input energy can be reduced by reducing the pulse number of low energy pulse group and increasing the base value time.
The result shows that the input energy can be reduced by about 14% under the condition of reducing the current of 8A by adjusting the number of pulses of the low-energy pulse group, and the TP-MIWW has better grain refining effect than DP-MIWW.
The invention has at least the following effects: (1) the heat input can be effectively controlled, and the energy input is reduced. The output current is set according to the welding characteristics and the power requirements, the number of strong and weak pulses can be conveniently changed through different output control parameters of the DSP controller, different heat inputs can be obtained, and the reasonable number of the strong and weak pulses can be selected, so that the heat inputs are greatly reduced, and the welding stability is realized.
(2) The design requirements of hardware circuits are reduced. The welding machine power supply system with pulse welding current output is a digital welding machine system with self-learning function controlled by DSP, and comprises an inverter main circuit consisting of a rectifier filter circuit and an IGBT full bridge, a main transformer, a rectifier filter circuit, a DSP-based control system, an ARM-based full-digital panel and the like. Compared with the traditional welding machine, the intelligent welding machine has the characteristics of low cost and intellectualization.
It is clear that the specific implementation of the invention is not restricted to the above-described embodiments, but that various insubstantial modifications of the inventive process concept and technical solutions are within the scope of protection of the invention.
Claims (5)
1. An output device of a pulse current, characterized in that: the alternating current is input to the input end of the front-end rectifying and filtering circuit, the output end of the rectifying and filtering circuit is connected with the input end of the inverter, the output end of the inverter is connected with the input end of the transformer, and the output end of the transformer outputs pulse current after being rectified and filtered by the rear-end rectifying and filtering circuit;
the output device comprises a main control chip, the input end of the main control chip is respectively connected with a current acquisition module and a voltage acquisition module, the voltage acquisition module is used for acquiring the output voltage of the rear-end rectifying and filtering circuit, and the current acquisition module is used for respectively acquiring the current signal at the output end of the transformer and the output current signal of the rear-end rectifying and filtering circuit;
the output end of the main control chip outputs a pulse modulation signal to the inverter for controlling the conduction or non-conduction and the duty ratio of a transistor in the inverter; furthermore, parameters of the inverter are controlled through pulse modulation signals to control the rear-end rectifying and filtering circuit to output double-pulse current, and the average current during welding is controlled through controlling the number of pulses of pulse groups in the double-pulse current; controlling the duty ratio of the inverter by controlling the pulse modulation signal to reduce the number of pulses of the low-energy pulse group in the double-pulse current;
the DSP output control reduces the control parameter of the number of the low energy pulse and calibrates the proper value according to a plurality of tests, the specific control number needs to be obtained through a process evaluation test, the process evaluation determines the number of pulses in each working condition by making a series of working conditions to form a process database, the process database is directly called later, and the corresponding double pulse current is controlled to output according to the DSP output parameter corresponding to the tool database.
2. The output device of a pulse current according to claim 1, wherein: the front-end rectifying and filtering circuit comprises a rectifier and a direct current filter, alternating current is input to the input end of the rectifier and converted into direct current to be output to the direct current filter, and the output end of the direct current filter is connected with the input end of the inverter.
3. The output device of a pulse current according to claim 1, wherein: the rear-end rectifying and filtering circuit comprises a diode full-wave rectifying circuit and a filter reactor, wherein the input end of the diode full-wave rectifying circuit is connected with the output end of the transformer, and the output end of the diode full-wave rectifying circuit outputs pulse current through the filter reactor.
4. A pulse current output control method is characterized in that: comprises the following steps
S1: converting industrial alternating current into direct current through rectification;
s2: filtering out alternating current components in the direct current;
s3: controlling an inverter to invert the filtered direct current into intermediate-frequency alternating current through a pulse modulation signal;
s4: converting the medium-frequency alternating current into low-voltage large-current alternating current;
s5: rectifying and filtering the low-voltage large-current alternating current to convert the low-voltage large-current alternating current into low-voltage large-current pulse direct current; the main control chip of the output device is connected with a current acquisition module, and the current acquisition module is used for respectively acquiring a current signal at the output end of the transformer and a current signal output by the rear-end rectifying and filtering circuit;
the output end of the main control chip outputs a pulse modulation signal to the inverter, the inverter parameter is controlled through the pulse modulation signal to control the rear-end rectifying and filtering circuit to output double-pulse current, and the average current during welding is controlled through controlling the number of pulses of a pulse group in the double-pulse current; the ratio of the number of strong current pulses to the number of weak current pulses in a unit period is changed by controlling the conduction of the inverter so as to control the heat input during welding;
controlling the duty ratio and frequency of the inverter by controlling the pulse modulation signal to reduce the number of pulses of the low-energy pulse group in the double-pulse current;
the DSP output control reduces the control parameter of the number of the low energy pulse and calibrates the proper value according to a plurality of tests, the specific control number needs to be obtained through a process evaluation test, the process evaluation determines the number of pulses in each working condition by making a series of working conditions to form a process database, the process database is directly called later, and the corresponding double pulse current is controlled to output according to the DSP output parameter corresponding to the tool database.
5. The pulse current output control method according to claim 4, characterized in that: and the high-current pulse direct current output by the step S5 is used for supplying power for aluminum alloy welding.
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| CN1871093A (en) * | 2003-10-23 | 2006-11-29 | 弗罗纽斯国际有限公司 | Method for controlling a welding process and welding device for carrying out a welding process |
| CN102091850A (en) * | 2010-12-31 | 2011-06-15 | 广东易事特电源股份有限公司 | Aluminum alloy digital welding machine with smooth transition double-pulse parameters |
| CN105269117A (en) * | 2015-10-27 | 2016-01-27 | 华南理工大学 | High-power double-wire pulse MIG welding low-frequency modulation type double-pulse control system |
| CN110076429A (en) * | 2019-05-15 | 2019-08-02 | 贵州民族大学 | A kind of MIG welder |
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| CN1871093A (en) * | 2003-10-23 | 2006-11-29 | 弗罗纽斯国际有限公司 | Method for controlling a welding process and welding device for carrying out a welding process |
| CN102091850A (en) * | 2010-12-31 | 2011-06-15 | 广东易事特电源股份有限公司 | Aluminum alloy digital welding machine with smooth transition double-pulse parameters |
| CN105269117A (en) * | 2015-10-27 | 2016-01-27 | 华南理工大学 | High-power double-wire pulse MIG welding low-frequency modulation type double-pulse control system |
| CN110076429A (en) * | 2019-05-15 | 2019-08-02 | 贵州民族大学 | A kind of MIG welder |
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