CN210080923U

CN210080923U - Fast-frequency pulse TIG welding system

Info

Publication number: CN210080923U
Application number: CN201920788516.5U
Authority: CN
Inventors: 王振民; 吴健文; 范文艳; 陈浩宇
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2020-02-18
Anticipated expiration: 2029-05-29

Abstract

The utility model provides a fast pulse TIG welding system frequently, its characterized in that: the method comprises a fast frequency pulse TIG welding power supply; the fast-frequency pulse TIG welding power supply comprises a main circuit, a control circuit and a human-computer interaction system; the main circuit comprises a power frequency rectifying and filtering module, a pulse current main circuit, a fundamental current main circuit and a high-frequency current switching circuit; the pulse current main circuit comprises a SiC full-bridge inversion commutation module I, a high-frequency transformation module I and a SiC rectification smoothing module I which are sequentially connected; the fundamental current main circuit comprises a SiC full-bridge inversion commutation module II, a high-frequency transformation module II and a SiC rectification smoothing module II which are sequentially connected; the high-frequency current switching circuit comprises a high-frequency switching module and an anti-reverse-filling module which are sequentially connected; and the first SiC full-bridge inversion commutation module comprises a SiC power switch tube. The welding system has high inversion frequency, good dynamic characteristics and stability, and can reduce the switching loss of the power tube.

Description

Fast-frequency pulse TIG welding system

Technical Field

The utility model relates to a welding equipment technical field, more specifically say, relate to a fast pulse TIG welding system frequently.

Background

In the field of welding, argon tungsten arc welding (TIG welding for short) is widely used due to the advantages of stable electric arc, zero spatter, high welding quality, wide range of weldable metal and the like. The pulse TIG welding technology starting in the middle of the 60's of the last century is that pulse current with certain frequency is superposed on the basis of traditional DC arc welding, peak current can make electric arc keep stable and accelerate the melting of parent metal to form molten pool, and base current can control heat input and maintain the continuous combustion of electric arc to make molten pool cool and crystallize, and the two are circularly alternated to form welding seam with good performance. At present, high-frequency pulse TIG shrinks an electric arc through an electromagnetic field generated by high-frequency current so as to improve the energy density of the electric arc and the stiffness of the electric arc, and can refine grains and improve the structure performance of a welding seam through strong stirring of a molten pool.

Therefore, the method is successively put into the research of the fast frequency pulse TIG welding equipment at home and abroad. In fast pulse TIG welding systems, the quality of the welding power supply is closely related to the performance of the welding arc, which not only provides precise energy to the welding process, but also allows for coordinated operation with other devices of the system. However, a great gap exists between the industrialization level of the domestic fast-frequency pulse TIG welding equipment and developed countries, the welding power supply generally adopts Si-based IGBT as a main device for power conversion, the switching performance of the traditional Si-based power device is close to the theoretical limit determined by the material performance of the traditional Si-based power device, several key indexes which influence the reliability of the fast-frequency pulse TIG welding, such as inversion frequency, response speed and the like in the welding power supply, are restricted to a certain extent, and the whole machine is overlarge in size and poor in dynamic characteristic. In addition, the fast-frequency pulse TIG welding technology adds the modulation of high-frequency current, which can generate strong electromagnetic interference on a welding power supply, and easily causes the problems of unstable welding current and poor control effect of high-frequency arc. Therefore, the fast frequency pulse TIG welding technology cannot be widely applied in China.

SUMMERY OF THE UTILITY MODEL

For overcoming the shortcoming and not enough among the prior art, the utility model aims to provide an contravariant frequency is high, have good dynamic characteristic and stability, can reduce power tube switching loss's fast pulse TIG welding system.

In order to achieve the above purpose, the utility model discloses a following technical scheme realizes: the utility model provides a fast frequency pulse TIG welding system which characterized in that: the method comprises a fast frequency pulse TIG welding power supply; the fast-frequency pulse TIG welding power supply comprises a main circuit, a control circuit and a human-computer interaction system;

the main circuit comprises a power frequency rectifying and filtering module, a pulse current main circuit, a fundamental current main circuit and a high-frequency current switching circuit; the pulse current main circuit comprises a SiC full-bridge inversion commutation module I, a high-frequency transformation module I and a SiC rectification smoothing module I which are sequentially connected; the fundamental current main circuit comprises a SiC full-bridge inversion commutation module II, a high-frequency transformation module II and a SiC rectification smoothing module II which are sequentially connected; the high-frequency current switching circuit comprises a high-frequency switching module and an anti-reverse-filling module which are sequentially connected; the SiC full-bridge inversion commutation module I comprises a SiC power switch tube;

the three-phase alternating current input power supply is connected with the power frequency rectification filter module; the power frequency rectification filtering module is respectively connected with the SiC full-bridge inversion commutation module I and the SiC full-bridge inversion commutation module II; the SiC rectification smoothing module I is connected with the high-frequency switching module; the anti-reverse-filling module is connected with an external arc load; the SiC rectification smoothing module II is connected with an external arc load;

the control circuit comprises an ARM minimum control system, a man-machine interaction communication module, a SiC high-frequency driving circuit, a change-over switch driving circuit and an output voltage and current sampling feedback circuit, wherein the man-machine interaction communication module, the SiC high-frequency driving circuit, the change-over switch driving circuit and the output voltage and current sampling feedback circuit are respectively connected with the ARM minimum control system; the SiC high-frequency driving circuit is respectively connected with the SiC full-bridge inversion commutation module I and the SiC full-bridge inversion commutation module II; the switch driving circuit is connected with the high-frequency switching module; the output voltage and current sampling feedback circuit is respectively connected with an external arc load, the SiC rectification smoothing module I and the SiC rectification smoothing module II; the man-machine interaction communication module is connected with the man-machine interaction system.

Preferably, the first SiC full-bridge inversion commutation module includes a SiC power switch tube, and means: the SiC full-bridge inversion commutation module I comprises a SiC power switch tube M101, a SiC power switch tube M102, a SiC power switch tube M103 and a SiC power switch tube M104; the high-frequency transformation module I comprises a high-frequency transformer I T101; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 form a full-bridge inverter circuit, and then are connected with the primary side of the high-frequency transformer I T101 through a blocking capacitor C109; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 are respectively connected with a RC absorption circuit I in parallel;

the SiC rectification smoothing module comprises a rectifier diode VD101, a rectifier diode VD102 and an inductor L101; a first output end of the secondary side of the high-frequency transformer I T101 is connected with a third output end of the secondary side of the high-frequency transformer I T101 through a rectifier diode VD101 and a rectifier diode VD102 which are connected in sequence; the junction of the rectifying diode VD101 and the rectifying diode VD102 is connected with one end of the inductor L101; the other end of the inductor L101 and a second output end of a secondary side of the first high-frequency transformer T101 are respectively used as output ends of the pulse current main circuit to be connected with the high-frequency switching module.

Preferably, the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 form a full-bridge inverter circuit, and then are connected with the primary side of the first high-frequency transformer module through a blocking capacitor C109; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 are respectively connected in parallel with a RC absorption circuit I, which means that:

the circuit also comprises a capacitor C101, a capacitor C102, a capacitor C103, a capacitor C104, a capacitor C109, a resistor R101, a resistor R102, a resistor R103 and a resistor R104;

after the SiC power switch tube M101 and the SiC power switch tube M103 are connected in series, the SiC power switch tube M102 and the SiC power switch tube M104 are connected in series to form a circuit, and the circuit are connected in parallel to a power frequency rectifying and filtering circuit; the capacitor C101 and the resistor R101 are connected in series and then connected to the SiC power switch tube M101 in parallel; the capacitor C102 and the resistor R102 are connected in series and then connected to the SiC power switch tube M102 in parallel; the capacitor C103 and the resistor R103 are connected in series and then connected to the SiC power switch tube M103 in parallel; the capacitor C104 and the resistor R104 are connected in series and then connected to the SiC power switch tube M104 in parallel; the junction of the SiC power switch tube M101 and the SiC power switch tube M103 is connected with a capacitor C109 in series and then is connected with a primary first input end of a first high-frequency transformation module; and the connection part of the SiC power switch tube M102 and the SiC power switch tube M104 is connected with the primary second input end of the first high-frequency transformation module.

Preferably, the circuit structure of the SiC full-bridge inversion commutation module ii is the same as that of the SiC full-bridge inversion commutation module i; the circuit structure of the high-frequency transformation module II is the same as that of the high-frequency transformation module I; and the circuit structure of the second SiC rectification and smoothing module is the same as that of the first SiC rectification and smoothing module.

Preferably, the high-frequency switching module comprises a modulation switch tube IGBT Q202 and a modulation switch tube IGBT Q201; the reverse-irrigation preventing module comprises a rectifier diode VD 201; the modulation switch tube IGBT Q201 is connected in parallel to the first SiC rectification smoothing module; the first SiC rectification smoothing module is connected with an external arc load through a modulation switching tube IGBT Q202 and a rectifier diode VD201 which are connected in sequence; the modulation switch tube IGBT Q202 is connected with a first peak voltage absorption module in parallel; and the modulation switch tube IGBT Q201 is connected with a second peak voltage absorption module in parallel.

Preferably, the first spike voltage absorption module comprises a capacitor C202, a resistor R202, a diode D204 and a diode D203; a circuit formed by connecting the resistor R202 and the capacitor C202 in parallel and then connecting the resistor R202 and the diode D204 in series is connected to the modulation switch tube IGBTQ202 in parallel; the diode D203 is connected in parallel with the modulation switch tube IGBT Q202;

the second spike voltage absorption module comprises a capacitor C201, a resistor R201, a diode D202 and a diode D201; a circuit formed by connecting a resistor R201 and a diode D202 in parallel and then connecting the resistor R with a capacitor C201 in series is connected to a modulation switching tube IGBT Q201 in parallel; the diode D201 is connected in parallel with the modulation switch tube IGBT Q201.

Preferably, the ARM minimum control system is connected with the SiC high-frequency drive circuit through an isolation I; and the ARM minimum control system is connected with the change-over switch driving circuit through the second isolation switch.

Preferably, the ARM minimum control system is connected to the SiC high frequency driving circuit through an isolation one, which means:

the ARM minimum control system is connected with the SiC high-frequency drive circuit through an isolation drive chip with the model number of ISO5451, and the isolation drive chip is also connected with a first drive power supply circuit;

the SiC high-frequency driving circuit comprises a capacitor C304, a capacitor C305, a voltage regulator tube ZD301, a diode D302, a diode D303, a resistor R310, a resistor R311, a resistor R312 and a resistor R313; a pin CLAMP of the isolation driving chip is connected with a grid electrode of the SiC power switch tube; the gate of the SiC power switch tube is grounded through a resistor R313 and a capacitor C305 which are connected in parallel; a pin OUT of the isolation driving chip is connected with a grid electrode of the SiC power switch tube through a resistor R312; the diode D303 and the resistor R311 are connected in series and then connected in parallel to the resistor R312; a pin OUT of the isolation driving chip is connected with a drain electrode of the SiC power switch tube through a resistor R310 and a diode D302 which are connected in series; the pin OUT of the isolation driving chip is also grounded through a capacitor C304 and a voltage stabilizing diode ZD301 which are connected in parallel; the terminal DESAT of the isolation driving chip is connected with the terminal OUT of the isolation driving chip.

Preferably, the ARM minimum control system is connected to the transfer switch driving circuit through the second isolation, which means: the ARM minimum control system is connected with the switch driving circuit through an optical coupling isolation chip; the change-over switch driving circuit comprises an NPN triode Q401, an NPN triode Q402, an NPN triode Q404, a PNP triode Q403 and a driving power supply circuit II;

the output end of the optical coupling isolation chip is connected with the base electrode of an NPN triode Q401 through a resistor R402, a resistor R403 and a diode D402 which are connected in sequence; the resistor R403 is connected with a capacitor C401 in parallel; the diode D403 is connected in parallel with the diode D402 in the reverse direction; the junction of the resistor R403 and the diode D402 is connected with the collector of the NPN triode Q401 through the diode D401; the collector of the NPN triode Q401 is also connected with the positive pole of the driving power supply circuit through a resistor R404;

the connection part of the resistor R402 and the resistor R403 is connected with the base electrode of the NPN triode Q402 through a resistor R408 and a diode D408 which are connected in sequence; the resistor R408 is connected with a capacitor C403 in parallel; the diode D408 is reversely connected with a diode D409 in parallel; the junction of the resistor R408 and the diode D408 is connected with the collector of the NPN triode Q402 through a diode D407; the collector of the NPN triode Q402 is also connected with the positive pole of the driving power supply circuit through a resistor R409; an emitting electrode of the NPN triode Q401 and an emitting electrode of the NPN triode Q402 are respectively connected with the negative electrode of the driving power supply circuit II;

the collector of the NPN triode Q401 is connected with the base of the PNP triode Q403 through a resistor R405 and a diode D405 which are connected in sequence; the resistor R405 is connected with a capacitor C402 in parallel; the diode C405 is reversely connected with the diode D404 in parallel; the junction of the resistor R405 and the diode D405 is connected with the collector of the PNP triode Q403 through a diode D406; the base electrode of the PNP triode Q403 is connected with the second positive electrode of the driving power supply circuit through a resistor R406; the emitter of the PNP triode Q403 is connected with the second positive electrode of the driving power supply circuit through a resistor R407;

the collector of the NPN triode Q402 is connected with the base of the NPN triode Q404 through a resistor R410 and a diode D411 which are connected in sequence; the resistor R410 is connected with a capacitor C404 in parallel; the diode D412 is connected in parallel in the reverse direction with the diode D411; the junction of the resistor R410 and the diode D411 is connected with the collector of the NPN triode Q404 through the diode D410; the collector of the NPN triode Q404 is connected with the collector of the PNP triode Q403; an emitter of the NPN triode Q404 is connected with the second cathode of the driving power supply circuit through a resistor R411; the collector of the NPN triode Q404 is connected with the second negative electrode of the driving power supply circuit through a resistor R412; the collector of the NPN triode Q404 is connected with the high-frequency switching module.

Preferably, the welding device further comprises an industrial robot, a wire feeder, a welding gun, a gas feeding device and a clamp; the industrial robot and the wire feeder are respectively connected with an ARM minimum control system; the fixture is respectively connected with the industrial robot and the welding gun; the fast-frequency pulse TIG welding power supply is also connected with an air supply device; the welding gun is also connected with the air supply device and the wire feeder respectively.

Compared with the prior art, the utility model has the advantages of as follows and beneficial effect:

1. compared with the traditional pulse TIG welding system, the power switch device of the fast-frequency pulse TIG welding power supply adopts a novel SiC power switch tube, the inversion frequency is up to 100kHz, and compared with the IGBT which is more commonly used at present, the inversion frequency is improved by nearly ten times, so that the size of the whole machine is greatly reduced, and the power switch device also has good dynamic response speed; the control effect of high-frequency arc is enhanced, the waveform of 20kHz fast-frequency pulse current is stably output, and the waveform is stable and undistorted in the welding process;

2. in the utility model, the fast frequency pulse TIG welding power supply has high energy efficiency; due to the excellent performance of the SiC power switch tube, the switching loss and the conduction loss of the SiC power switch tube are small, so that the energy efficiency of a TIG welding power supply is greatly improved;

3. in the utility model, the high-frequency current switching circuit can effectively absorb the sharp pulse overvoltage generated in the high-frequency pulse current modulation process, and can not destroy the basic waveform of the fast-frequency pulse current, and the high-frequency current switching circuit has simple structure, low cost and high reliability;

4. the utility model realizes the ARM minimum control system and the SiC high frequency drive circuit in a sampling isolation mode, and the ARM minimum control system is connected with the drive circuit of the change-over switch; the protection circuit has multiple protection functions, and can prevent the switch tube from being damaged while effectively driving the switch tube; the problems of overhigh transient voltage and transient current and electromagnetic interference in the drive process of the SiC power switch tube can be inhibited, the false triggering caused by voltage spike can be prevented, and the drive effect is good;

5. the utility model discloses fast pulse TIG welding system has combined high frequency contravariant, digital automatic control etc. technique to and carry out the operation in coordination with each part of system through the CAN bus, make the integrated level of system higher, control more accurate.

Drawings

FIG. 1 is a system block diagram of the fast frequency pulse TIG welding system of the present invention;

FIG. 2 is a schematic structural diagram of a fast frequency pulse TIG welding power supply in the fast frequency pulse TIG welding system of the present invention;

FIG. 3 is a circuit diagram of the main circuit of the fast pulse TIG welding power supply in the fast pulse TIG welding system of the present invention;

FIG. 4 is a circuit diagram of a SiC high frequency drive circuit of a fast frequency pulse TIG welding power supply in the fast frequency pulse TIG welding system of the present invention;

fig. 5 is a circuit diagram of a change-over switch driving circuit of a fast-frequency pulse TIG welding power supply in the fast-frequency pulse TIG welding system of the present invention;

FIG. 6 is a circuit diagram of the output voltage current sampling feedback circuit of the fast pulse TIG welding power supply in the fast pulse TIG welding system of the present invention;

fig. 7 is a block diagram of the wire feeder in the fast pulse TIG welding system of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Examples

The structure of the fast-frequency pulse TIG welding system is shown in figures 1 to 7, and the fast-frequency pulse TIG welding system comprises a fast-frequency pulse TIG welding power supply, an industrial robot, a wire feeder, a welding gun, a gas supply device and a clamp; the industrial robot and the wire feeder are respectively connected with the ARM minimum control system; the fixture is respectively connected with the industrial robot and the welding gun; the fast-frequency pulse TIG welding power supply is also connected with an air supply device; the welding gun is also connected with the air supply device and the wire feeder respectively.

The industrial robot is used as an executing mechanism for clamping the welding gun to perform welding operation according to a set path. The wire feeder is used for realizing accurate stepless regulation of the feeding speed of the welding wire and diversification of wire feeding modes, and ensures that the feeding of the welding wire can be perfectly matched with a welding process and parameters. The air supply device is used for providing shielding gas. The fixture is used for realizing the functions of fixing and shifting a welding workpiece, connecting a welding gun with an industrial robot and the like.

The fast-frequency pulse TIG welding power supply comprises a main circuit, a control circuit and a human-computer interaction system.

The main circuit comprises a power frequency rectifying and filtering module, a pulse current main circuit, a fundamental current main circuit and a high-frequency current switching circuit. The pulse current main circuit and the fundamental current main circuit are mainly used for providing energy for electric arcs, the high-frequency current switching circuit is used for modulating high-frequency current, and the control circuit is used for achieving the functions of generation of IGBT driving signals of the SiC power switch tube and the modulation switch tube, closed-loop regulation of sampling current, fault protection, cooperative communication with other parts of a system, man-machine interaction and the like.

The pulse current main circuit comprises a SiC full-bridge inversion commutation module I, a high-frequency transformation module I and a SiC rectification smoothing module I which are sequentially connected; the fundamental current main circuit comprises a SiC full-bridge inversion commutation module II, a high-frequency transformation module II and a SiC rectification smoothing module II which are sequentially connected; the high-frequency current switching circuit comprises a high-frequency switching module and an anti-reverse-filling module which are sequentially connected; the SiC full-bridge inversion commutation module I comprises a SiC power switch tube; the high-frequency switching module comprises an IGBT switching tube;

The ARM minimum control system adopts a 32-bit high-speed ARM microprocessor which generates three groups of full-digital PWM control signals which respectively act on a pulse current main circuit, a basic value current main circuit and a high-frequency current switching circuit; and the UART communication interface circuit of the ARM minimum control system is connected with the human-computer interaction system, and the CAN communication interface circuit of the ARM minimum control system is connected with the CAN bus to complete the mutual cooperative operation of all the parts of the system. The relay module is mainly used for opening and closing the air valve.

The SiC full-bridge inversion commutation module I comprises a SiC power switch tube M101, a SiC power switch tube M102, a SiC power switch tube M103 and a SiC power switch tube M104; the high-frequency transformation module I comprises a high-frequency transformer I T101; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 form a full-bridge inverter circuit, and then are connected with the primary side of the high-frequency transformer I T101 through a blocking capacitor C109; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 are respectively connected with a RC absorption circuit I in parallel;

the SiC rectification smoothing module comprises a rectifier diode VD101, a rectifier diode VD102 and an inductor L101; a first output end of the secondary side of the high-frequency transformer I T101 is connected with a third output end of the secondary side of the high-frequency transformer I T101 through a rectifier diode VD101 and a rectifier diode VD102 which are connected in sequence; the junction of the rectifying diode VD101 and the rectifying diode VD102 is connected with one end of the inductor L101; the other end of the inductor L101 and a second output end of a secondary side of the first high-frequency transformer T101 are respectively used as output ends of the pulse current main circuit to be connected with the high-frequency switching module. Specifically, the capacitor C101, the capacitor C102, the capacitor C103, the capacitor C104, the capacitor C109, the resistor R101, the resistor R102, the resistor R103 and the resistor R104 are further included;

In the fundamental current main circuit, the circuit structure of the SiC full-bridge inversion commutation module II is the same as that of the SiC full-bridge inversion commutation module I; the circuit structure of the high-frequency transformation module II is the same as that of the high-frequency transformation module I; and the circuit structure of the second SiC rectification and smoothing module is the same as that of the first SiC rectification and smoothing module. The structure and principle of the fundamental current main circuit are the same as those of the pulse current main circuit. The SiC high-frequency driving circuit used for driving the SiC full-bridge inversion commutation module I and the SiC high-frequency driving circuit used for driving the SiC full-bridge inversion commutation module II are identical in structure and only different in output driving waveform and time sequence; the drive waveforms and timing may be in conventional manner.

The working principle of the main circuit is as follows: the AC input power is connected with a power frequency rectifying and filtering module to be converted into smooth DC; direct current passes through a SiC full-bridge inversion conversion module I of a pulse current main circuit, two paths of PWM signals with complementary dead zones control two opposite-angle SiC power switch tubes to be simultaneously switched on or switched off in a high-frequency mode, and the direct current is converted into high-frequency alternating current; then, the high-frequency transformation module I is used for electrical isolation, transformation and power transmission; the direct current which is converted into low-voltage smooth direct current through the SiC rectification smoothing module II is input into the high-frequency switching module, two paths of complementary PWM signals without dead zones control the two modulation switching tube IGBTs to be alternately switched on and off at the frequency of 20kHz, the direct current is converted into high-frequency current, the high-frequency current is superposed with the fundamental value direct current output by the fundamental value current main circuit after passing through the reverse filling prevention module, and the fast-frequency pulse current generated by superposition is output to an external electric arc load.

The high-frequency switching module comprises a modulation switch tube IGBT Q202 and a modulation switch tube IGBT Q201; the reverse-irrigation preventing module comprises a rectifier diode VD 201; the modulation switch tube IGBT Q201 is connected in parallel to the first SiC rectification smoothing module; the first SiC rectification smoothing module is connected with an external arc load through a modulation switching tube IGBT Q202 and a rectifier diode VD201 which are connected in sequence; the modulation switch tube IGBT Q202 is connected with a first peak voltage absorption module in parallel; and the modulation switch tube IGBT Q201 is connected with a second peak voltage absorption module in parallel.

The first spike voltage absorption module comprises a capacitor C202, a resistor R202, a diode D204 and a diode D203; a circuit formed by connecting a resistor R202 and a capacitor C202 in parallel and then connecting the resistor R202 and a diode D204 in series is connected to a modulation switching tube IGBT Q202 in parallel; the diode D203 is connected in parallel with the modulation switch tube IGBT Q202;

In the high-frequency current switching circuit, low-voltage direct current output by a pulse current main circuit is input into a high-frequency switching module formed by a modulation switching tube IGBT Q201 and a modulation switching tube IGBT Q202, two paths of complementary no-dead-zone PWM signals control the modulation switching tube IGBT 201 and the modulation switching tube IGBT Q202 to be alternately switched on and off at the frequency of 20kHz or higher, the direct current is converted into high-frequency current, the high-frequency current passes through an anti-recharging module and then is superposed with the low-voltage direct current output by a fundamental current main circuit, and the superposed high-frequency pulse current is output to an external arc load; the peak voltage absorption module I and the peak voltage absorption module absorb peak voltages generated in the process of modulating the high-frequency current; the rectifier diode VD201 prevents direct current output by the fundamental current main circuit from flowing back to the pulse current main circuit through the internal resistance of the high-frequency current switching circuit, and the influence on the accurate output control of a power supply is avoided.

And the ARM minimum control system is connected with the SiC high-frequency drive circuit through an isolation I.

Specifically, the ARM minimum control system is connected with the SiC high-frequency drive circuit through an isolation drive chip with the model number of ISO5451, and the isolation drive chip is further connected with a first drive power supply circuit;

And the ARM minimum control system is connected with the change-over switch driving circuit through the second isolation switch. Specifically, the ARM minimum control system is connected with a switch driving circuit through an optical coupling isolation chip; the change-over switch driving circuit comprises an NPN triode Q401, an NPN triode Q402, an NPN triode Q404, a PNP triode Q403 and a driving power supply circuit II;

The control system and the modulation switch tube driving circuit are driven in an optical coupling isolation mode, the optical coupling is a high-speed optical coupling HCPL-3120 special for IGBT or MOSFET, the switching delay time is about 0.3us, and the high-speed optical coupling has small volume, high switching speed and strong impact resistance and can meet the driving design requirement. Because the modulation switch tube driving circuit generates two complementary driving electric signals without dead zones, the grid driving circuit structures of the two modulation IGBT switch tubes are the same, one of the two modulation IGBT switch tubes is intercepted, the isolation optocoupler is connected with a half-bridge topological structure formed by two MOSFETs, and finally, the +15V/-7V voltage is output to drive the modulation IGBT switch tube. The benefits of this setup are: the switch has the advantages of small volume, high switching speed and strong shock resistance, and meets the design requirements of driving.

The output voltage and current sampling feedback circuit is respectively used for collecting the output voltage and current of the pulse current main circuit and the fundamental current main circuit. As shown in fig. 5, the output voltage and current sampling feedback circuit includes a 200A current hall sensor with model number HAS 200-P, an integrated differential amplifying circuit composed of a differential amplifier with model number AD629 and its peripheral circuits, and a low-pass filter circuit composed of a chip with model number OP177 and its peripheral circuits; the current Hall sensor, the integrated differential amplifying circuit and the low-pass filter circuit are connected in sequence.

The measurement voltage value converted back by the current hall sensor needs to be divided by resistors R501 and R502 and then connected to an integrated differential amplification circuit, wherein U501 is a differential amplifier AD629 with low offset, low gain error drift and high common mode rejection ratio, and the amplification factor is 1. Filtering is performed through a KRC active low-pass filter, a more flat Butterworth filter in a passband is used as a model in the method, wherein U502 is an operational amplifier OP177 with high precision and low zero drift, and the U502 is matched with values of external resistance capacitors R503, R504, C505 and C506.

In the pulse current main circuit and the fundamental current main circuit, the SiC power switch tube is rapidly switched on and off according to a preset time sequence to realize high-frequency direct current and alternating current conversion; two modulation switching tubes IGBT of the high-frequency switching module are alternately switched at a frequency of 20kHz or higher, so that the output voltage and current sampling feedback independent control of two paths of pulse current main circuits and a fundamental current main circuit which are connected in parallel for modulating high-frequency pulse current is realized; the output current and voltage are respectively collected and subjected to signal conditioning at the output ends of the pulse current main circuit and the fundamental current main circuit, and after the output current and voltage are compared with a preset value, the on-off time of the SiC power switch tube is changed, the duty ratio regulation is realized, the required waveform output is obtained, and the closed-loop control is completed.

The wire feeder comprises a motor, a clamping wheel, a fixed support and a wire feeding control system. The wire feeding control system comprises a power supply module, an ARM microprocessor, a motor half-bridge driving circuit, a voltage sampling feedback circuit and a digital control panel. The half-bridge driving circuit can adopt the prior art, for example, the wire feeding driving circuit disclosed in detail in the invention of intelligent arc welding robot diving wire feeder (publication number: 103706927B) of China. The half-bridge driving circuit is mainly formed by connecting a half-bridge circuit consisting of 2N-channel field effect transistors Q1 and a field effect transistor Q2, a driving chip IR2110, an optocoupler PC817, a relay K1, a voltage stabilizing chip L7815 and other peripheral circuits. The driving chip is in the type IR2110, and the forward rotation and the reverse rotation of the motor are converted through a reversing circuit formed by a relay K1 and an optocoupler PC 817. The two ends of the motor are connected with a connector P1, and two complementary PWM signals with dead zones are respectively input to the driving chip IR 2110. When PWMH is high level and PWML is low level, because of the function of a bootstrap circuit formed by capacitors C2 and C3 and a diode D1, a field effect tube Q1 is reliably conducted at the moment, the field effect tube Q2 is turned off, and the positive and negative ends of the motor are short-circuited at 24V and are in an emergency stop state; when PWMH is low level, PWL is high level, field effect transistor Q2 switches on, and field effect transistor Q1 switches off, and the voltage at both ends of the motor is +24V at this moment, and the motor is in the corotation state. When the Inversion end is kept at a low level, a triode of the optocoupler PC817 is conducted, a relay is kept at a reverse end, when PWMH is at a high level and PWML is at a low level, a field-effect tube Q1 is conducted, a field-effect tube Q2 is turned off, the voltage at two ends of the motor is +24V, and the motor is in a reverse state; when PWML is high level, PWMH is low level, the positive and negative both ends of motor are short connected in 24V, are in the scram state. Therefore, by controlling the high and low levels of the Inversion end of Inversion, the pulsating wire feeding can be realized, and by controlling the duty ratios of PWMH and PWML, the wire feeding speed can be controlled, and by combining the two modes, three wire feeding modes such as constant-speed wire feeding, variable-speed wire feeding and pulsating wire feeding can be conveniently realized.

The voltage sampling feedback circuit can adopt the prior art, such as a wire feeding speed detection circuit disclosed in detail in the invention of intelligent arc welding robot diving wire feeder (publication number: 103706927B) in China. The connector P3 of the voltage sampling feedback circuit is connected with the positive end and the negative end of the motor, the voltage at the two ends of the motor is subjected to resistance voltage division, differential amplification and linear optical coupling isolation, the voltage is further divided and then input to the control chip STM32F405RG, and the voltage is compared with a voltage set value after A/D conversion, so that the duty ratio of a PWM signal is adjusted, and the purpose of adjusting the running speed of the motor is achieved. The resistor R6, the resistor R7, the resistor R8, and the resistor R9 respectively form two voltage dividing circuits for inputting voltage, and the voltage is proportionally reduced to be suitable for the input voltage of the operational amplifier LF 353. The inductor L5, the inductor L6 and the capacitor C10 form an LC filter circuit at an input end. The operational amplifier U4 constitutes a differential amplification circuit, which amplifies the voltage at two ends of the motor after voltage reduction to two times, and then calculates the difference between the two voltages and outputs the difference, thereby converting the input differential signal into a single-side voltage signal to output. The diode D6, the diode D7, the diode D8 and the diode D9 are protection diodes at two input ends of the operational amplifier U4, respectively, and when the absolute value of the voltage at the input end is higher than 15V, one of the diodes is turned on, thereby effectively protecting the operational amplifier. Because the linear optical coupler U6 is a current-driven optical coupler element, and the isolated current is the current quantity, the operational amplifier U5 and the resistor R17 form a voltage-current conversion circuit, the voltage at the input end of the operational amplifier is converted into the LED driving current of the linear optical coupler HCNR201, the operational amplifier U5, the resistor R16, the capacitor C11 and the diode D10 form a closed loop feedback circuit of the linear optical coupler U6, so that the nonlinearity and the temperature drift of the LED of the U6 are compensated, and the capacitor C11 can also play a role in filtering high-frequency noise signals. The operational amplifier U7, the resistor R22 and the resistor R18 form a current-voltage conversion circuit, the output current of the linear optocoupler U6 is converted into voltage, the resistance value of the resistor R22 is adjusted to a proper value, a voltage value equal to the single-side output voltage of the operational amplifier U4 can be obtained, the voltage value is further reduced through the resistor R18, the output voltage of the operational amplifier U7 is reduced to the proper input voltage of the control chip STM32F405RG, wherein the diode D11 and the diode D12 form an input end protection circuit, and the voltage of a Feedback end is prevented from being higher than 3.3V.

The ARM microprocessor generates a group of PWM signals, and the PWM signals are amplified and isolated by the driving circuit and are used for driving a power switch tube in a half-bridge driving circuit of the motor, so that the motor is operated; the rotating speed of the motor is regulated by adopting an armature voltage control method, the armature voltage is obtained by sampling through a voltage sampling feedback circuit and is fed back to the ARM microprocessor, an ADC (analog-to-digital converter) module of the ARM microprocessor carries out analog-to-digital conversion on the fed-in signal, then the fed-in signal is compared with a given numerical value and is subjected to PI (proportional-integral) regulation, and then a driving signal with a corresponding pulse width is output, so that the closed-loop regulation of the armature voltage is realized, and the accurate stepless regulation of; the wire feeder is connected with other equipment of the system through a CAN, and the operation parameters of the wire feeder CAN be set by a fast-frequency pulse TIG welding power supply.

Industrial robots, welding guns, gas delivery devices and fixtures may employ existing technologies.

The utility model discloses fast pulse TIG welding system's theory of operation does: firstly, planning a welding path, setting a motion path of an industrial robot, then moving to a welding starting point, and waiting for a synchronous signal of a fast-frequency pulse TIG welding power supply; setting welding parameters through a human-computer interaction system and inputting the welding parameters into a fast-frequency pulse TIG welding power supply; after the fast-frequency pulse TIG welding power supply controls and starts the air supply device, a main circuit of the fast-frequency pulse TIG welding power supply firstly works, a high-frequency high-voltage arc striking circuit is utilized to break down an air gap between a tungsten electrode and a nozzle of a welding gun, and an electric arc is formed between a welding workpiece and the tungsten electrode; after the arc starting is successful, the fast-frequency pulse TIG welding power supply outputs a walking signal to the industrial robot, and the welding gun walks according to a set path and speed. Wherein industrial robot, man-machine interaction system, fast pulse TIG welding power supply, send a machine to all carry out high-speed digital cooperation through the CAN network to ensure that in whole welding process, each constitutes and CAN realize organic cooperation and high-speed cooperation, improved the automation and the intelligent level of fast pulse TIG welding process.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be equivalent replacement modes, and all are included in the scope of the present invention.

Claims

1. The utility model provides a fast frequency pulse TIG welding system which characterized in that: the method comprises a fast frequency pulse TIG welding power supply; the fast-frequency pulse TIG welding power supply comprises a main circuit, a control circuit and a human-computer interaction system;

2. A fast pulse TIG welding system according to claim 1, wherein: the SiC full-bridge inversion commutation module I comprises a SiC power switch tube, and means that: the SiC full-bridge inversion commutation module I comprises a SiC power switch tube M101, a SiC power switch tube M102, a SiC power switch tube M103 and a SiC power switch tube M104; the high-frequency transformation module I comprises a high-frequency transformer I T101; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 form a full-bridge inverter circuit, and then are connected with the primary side of the high-frequency transformer I T101 through a blocking capacitor C109; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 are respectively connected with a RC absorption circuit I in parallel;

3. A fast pulse TIG welding system according to claim 2, wherein: the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 form a full-bridge inverter circuit, and then are connected with the primary side of the first high-frequency transformation module through a blocking capacitor C109; the SiC power switch tube M101, the SiC power switch tube M102, the SiC power switch tube M103 and the SiC power switch tube M104 are respectively connected in parallel with a RC absorption circuit I, which means that:

4. A fast pulse TIG welding system according to claim 2, wherein: the circuit structure of the SiC full-bridge inversion commutation module II is the same as that of the SiC full-bridge inversion commutation module I; the circuit structure of the high-frequency transformation module II is the same as that of the high-frequency transformation module I; and the circuit structure of the second SiC rectification and smoothing module is the same as that of the first SiC rectification and smoothing module.

5. A fast pulse TIG welding system according to claim 2, wherein: the high-frequency switching module comprises a modulation switch tube IGBT Q202 and a modulation switch tube IGBT Q201; the reverse-irrigation preventing module comprises a rectifier diode VD 201; the modulation switch tube IGBT Q201 is connected in parallel to the first SiC rectification smoothing module; the first SiC rectification smoothing module is connected with an external arc load through a modulation switching tube IGBT Q202 and a rectifier diode VD201 which are connected in sequence; the modulation switch tube IGBT Q202 is connected with a first peak voltage absorption module in parallel; and the modulation switch tube IGBT Q201 is connected with a second peak voltage absorption module in parallel.

6. A fast frequency pulse TIG welding system according to claim 5, wherein: the first spike voltage absorption module comprises a capacitor C202, a resistor R202, a diode D204 and a diode D203; a circuit formed by connecting a resistor R202 and a capacitor C202 in parallel and then connecting the resistor R202 and a diode D204 in series is connected to a modulation switching tube IGBT Q202 in parallel; the diode D203 is connected in parallel with the modulation switch tube IGBT Q202;

7. A fast pulse TIG welding system according to claim 1, wherein: the ARM minimum control system is connected with the SiC high-frequency drive circuit through an isolation I; and the ARM minimum control system is connected with the change-over switch driving circuit through the second isolation switch.

8. A fast pulse TIG welding system according to claim 7, wherein: the ARM minimum control system is connected with the SiC high-frequency driving circuit through an isolation I, and means that:

9. A fast pulse TIG welding system according to claim 7, wherein: the ARM minimum control system is connected with the change-over switch driving circuit through the second isolation switch, and means that: the ARM minimum control system is connected with the switch driving circuit through an optical coupling isolation chip; the change-over switch driving circuit comprises an NPN triode Q401, an NPN triode Q402, an NPN triode Q404, a PNP triode Q403 and a driving power supply circuit II;

10. A fast pulse TIG welding system according to any of claims 1-9, wherein: the welding device also comprises an industrial robot, a wire feeder, a welding gun, a gas supply device and a clamp; the industrial robot and the wire feeder are respectively connected with an ARM minimum control system; the fixture is respectively connected with the industrial robot and the welding gun; the fast-frequency pulse TIG welding power supply is also connected with an air supply device; the welding gun is also connected with the air supply device and the wire feeder respectively.