A MIG welding machine and its arc starting control method, device and drive circuit

Abstract

The present invention discloses a MIG welding machine and its arc starting control method, device and drive circuit. The arc starting control method of the MIG welding machine includes: in response to an arc starting start signal, connecting an arc starting set voltage to the drive circuit; detecting the output current of the power supply circuit; when initially detecting the output current of the power supply circuit, increasing the response frequency of the drive circuit from a first response frequency to a second response frequency, so that the growth rate of the output current of the power supply circuit is increased from a first rate to a second rate; determining whether the output current reaches a current set peak value; if the output current reaches the current set peak value, removing the arc starting set voltage connected to the drive circuit and restoring the response frequency of the drive circuit. The solution of the present invention can improve the arc starting success rate and speed, and provide a more ideal arc starting effect.

Description

Technical Field

[0001] Embodiments of the present invention relate to welding technology, and in particular, to a MIG welding machine and its arc starting control method, device, and drive circuit. Background Art

[0002] There are various types of welding machines on the market, and the replacement is relatively rapid. Due to its advantages such as low welding cost, high production efficiency, and high welding quality, the MIG welding machine has long occupied a relatively dominant position in the market share.

[0003] Currently, the drive circuit of the MIG welding machine is as Figure 1 shown. When starting to strike an arc, an arc starting no-load voltage is connected to the voltage PI adjustment module 101, and the voltage error signal is calculated by combining the feedback voltage U F and the set voltage U S . After detecting that the current presence signal I Y is a current, the arc starting no-load voltage U K is removed to end the arc starting process. During the arc starting process, the arc characteristic control module 102 generates an arc characteristic signal based on the voltage error signal, and the current PI adjustment module 103 generates a current error signal according to the arc characteristic signal and the feedback current I F . The PWM regulator 104 adjusts the welding voltage and current according to the current error signal to achieve the control of the arc starting process.

[0004] However, the success rate of the existing arc starting method is low, the arc starting effect is not ideal, and it cannot meet the market demand. Summary of the Invention

[0005] The present invention provides a MIG welding machine and its arc starting control method, device, and drive circuit to improve the success rate and speed of arc starting and provide a more ideal arc starting effect.

[0006] In a first aspect, an embodiment of the present invention provides an arc starting control method for a MIG welding machine. The MIG welding machine includes a welding torch, a drive circuit, and a power supply circuit connected to the welding torch and the drive circuit and outputting an adjustable drive current;

[0007] The arc starting control method for the MIG welding machine includes:

[0008] Responding to an arc starting start signal, connecting an arc starting set voltage to the drive circuit;

[0009] Detecting the output current of the power supply circuit;

[0010] When initially detecting the output current of the power supply circuit, increasing the response frequency of the drive circuit from a first response frequency to a second response frequency, so that the growth rate of the output current of the power supply circuit is increased from a first rate to a second rate;

[0011] Determine whether the output current reaches the set peak current;

[0012] If the output current reaches the set peak current, remove the arc-starting set voltage applied to the drive circuit and restore the response frequency of the drive circuit.

[0013] Optionally, the drive circuit includes a voltage PI regulation module and a current characteristic control module;

[0014] Increasing the response frequency of the drive circuit from a first response frequency to a second response frequency includes:

[0015] Increasing the response frequencies of the voltage PI regulation module and the current characteristic control module from a third response frequency to a fourth response frequency, where the third response frequency is less than the fourth response frequency.

[0016] Optionally, before determining whether the output current reaches the set peak current, it further includes:

[0017] Increasing the set peak current from a first preset value to a second preset value;

[0018] When removing the arc-starting set voltage applied to the drive circuit and restoring the response frequency of the drive circuit, it further includes:

[0019] Restoring the set peak current from the second preset value to the first preset value.

[0020] In a second aspect, an embodiment of the present invention further provides an arc-starting control device for a MIG welder. The arc-starting control device for a MIG welder includes: a voltage introduction module, a current detection module, a rate adjustment module, a judgment module, and a restoration module. The voltage introduction module is used to respond to an arc-starting start signal and apply an arc-starting set voltage to the drive circuit; the current detection module is used to detect the output current of the power supply circuit;

[0021] The rate adjustment module is used to increase the response frequency of the drive circuit from a first response frequency to a second response frequency when initially detecting the output current of the power supply circuit, so that the growth rate of the output current of the power supply circuit is increased from a first rate to a second rate; the judgment module is used to judge whether the output current reaches the set peak current; the restoration module is used to, if the output current reaches the set peak current, remove the arc-starting set voltage of the drive circuit and restore the response frequency of the drive circuit.

[0022] Optionally, the rate adjustment module includes a response frequency adjustment unit, which is configured to increase the response frequencies of the voltage PI adjustment module and the current characteristic control module from a third response frequency to a fourth response frequency, where the third response frequency is less than the fourth response frequency.

[0023] Optionally, the arc starting control device further includes a peak adjustment module, which is configured to increase the value of the set peak current from a first preset value to a second preset value; the recovery module is further configured to restore the value of the set peak current from the second preset value to the first preset value.

[0024] In a third aspect, an embodiment of the present invention further provides a drive circuit for a MIG welder. The drive circuit of the MIG welder includes: a current detection circuit, a voltage PI adjustment circuit, an arc characteristic control circuit, a current PI adjustment circuit, and a PWM adjustment circuit;

[0025] The current detection circuit is configured to detect the output current and generate a signal indicating the presence or absence of the output current and a current feedback signal;

[0026] The voltage PI adjustment circuit is connected to the current detection circuit and is configured to determine a first voltage error signal according to the set arc starting voltage and the real-time welding feedback voltage during the arc starting process, and determine a second voltage error signal according to the set welding voltage and the welding feedback voltage during the welding process; where, during the arc starting process, the response frequency of the voltage PI adjustment circuit is the fourth response frequency when there is output current, and the response frequency of the voltage PI adjustment circuit is the third response frequency when there is no output current, and the third response frequency is lower than the fourth response frequency;

[0027] The arc characteristic control circuit is respectively connected to the voltage PI adjustment circuit and the current detection circuit, and is configured to generate a first arc characteristic signal according to the first voltage error signal, or generate a second arc characteristic signal according to the second voltage error signal; where, during the arc starting process, the response frequency of the arc characteristic control circuit is the fourth response frequency when there is output current, and the response frequency of the arc characteristic control circuit is the third response frequency when there is no output current;

[0028] The current PI adjustment circuit is respectively connected to the arc characteristic control circuit and the current detection circuit, and is configured to determine a current error signal according to the arc characteristic signal and the current feedback signal, where the arc characteristic signal includes the first arc characteristic signal or the second arc characteristic signal;

[0029] The PWM adjustment circuit is connected to the current PI adjustment circuit and is configured to output a PWM adjustment signal to the power supply circuit according to the current error signal to adjust the output current and the welding voltage.

[0030] Optionally, the first arc characteristic signal includes a set peak current;

[0031] The arc characteristic control circuit is further configured to set the set peak current to a first preset value if there is no output current during the arc starting process; and set the set peak current to a second preset value if there is output current, where the first preset value is less than the second preset value.

[0032] In a fourth aspect, the present invention further provides a MIG welding machine, which includes: a welding torch, the driving circuit according to any one of the third aspect of the claims, a power supply circuit, and the arc starting control device according to any one of the second aspect.

[0033] Optionally, the arc starting control device is integrated in a processor.

[0034] The MIG welding machine, the arc starting control method, device and driving circuit provided by the embodiments of the present invention respond to the arc starting start signal to connect an arc starting set voltage to the driving circuit to start the arc starting program. When initially detecting the output current of the power supply circuit, the response frequency of the driving circuit is increased, so that the growth rate of the output current of the power supply circuit is increased accordingly, and the energy output by the welding torch is increased in a short time, playing a role in quickly starting the arc. When the output current reaches the set peak current, the arc starting set voltage connected to the driving circuit is removed and the response frequency of the driving circuit is restored. Restoring the response frequency of the driving circuit can ensure the stable change of the current during the welding process and improve the controllability of the current change during the welding process. The arc starting control method provided by this embodiment improves the arc starting success rate and speed by increasing the growth rate of the output current of the power supply circuit, and provides a more ideal arc starting effect. Description of the Drawings

[0035] Figure 1 It is a schematic diagram of a driving circuit of a MIG welding machine in the prior art;

[0036] Figure 2 It is a schematic structural diagram of a MIG welding machine provided by an embodiment of the present invention;

[0037] Figure 3 It is a schematic flowchart of an arc starting control method of a MIG welding machine provided by an embodiment of the present invention;

[0038] Figure 4 It is a schematic flowchart of an arc starting control method of a MIG welding machine provided by an embodiment of the present invention;

[0039] Figure 5 It is a schematic structural diagram of an arc starting control device of a MIG welding machine provided by an embodiment of the present invention;

[0040] Figure 6 Schematic structural diagram of an arc starting control device for a MIG welder provided by an embodiment of the present invention;

[0041] Figure 7 Schematic structural diagram of a drive circuit for a MIG welder provided by an embodiment of the present invention;

[0042] Figure 8 Schematic structural diagram of a MIG welder provided by an embodiment of the present invention;

[0043] Figure 9 Simulation schematic diagram of welding voltage and output current of an existing MIG welder after arc starting;

[0044] Figure 10 Simulation schematic diagram of welding voltage and output current of a MIG welder provided by an embodiment of the present invention after arc starting;

[0045] Figure 11 Simulation schematic diagram of welding voltage and output current of another existing MIG welder after arc starting;

[0046] Figure 12 Simulation schematic diagram of welding voltage and output current of another MIG welder provided by an embodiment of the present invention after arc starting. Detailed implementation manners

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the drawings.

[0048] In a first aspect of an embodiment of the present invention, an arc starting control method for a MIG welder is provided, and this method is applicable to a MIG welder. Figure 2 Schematic structural diagram of a MIG welder provided by an embodiment of the present invention, referring to Figure 2, the MIG welder 200 includes a welding torch 201, a drive circuit 203, and a power supply circuit 202 that is connected to the welding torch 201 and the drive circuit 203 and outputs an adjustable drive current. The welding torch 201 refers to the device on the MIG welder 200 that outputs the welding wire and the shielding gas. Exemplarily, the welding torch 201 may include a fixture that can fixedly hold the welding material. The drive circuit 203 is respectively connected to the welding torch 201 and the power supply circuit 202, and the drive circuit 203 can control the power supply output by the power supply circuit 202 according to the electrical signal output by the welding torch 201. The power supply circuit 202 can output an adjustable current to the welding torch 201 according to the control signal of the drive circuit 203. During the welding process, the welding torch 201 converts the energy of the output current of the power supply circuit 202 into welding heat and continuously transfers it to the material to be welded.

[0049] Figure 3 It is a schematic flow chart of an arc starting control method for a MIG welder provided by an embodiment of the present invention. Refer to Figure 3 , the arc starting control method of the MIG welder includes:

[0050] S301. In response to the arc starting signal, set the arc starting voltage for the drive circuit.

[0051] Among them, the arc starting signal refers to the signal used to start the arc starting process of the MIG welder, which can be input by the user or triggered by the sensing signal. The drive circuit refers to the circuit in the MIG welder that provides the PWM adjustment signal for the power supply circuit and can adjust the output current and welding voltage of the power supply circuit. The arc starting set voltage refers to the preset voltage value that the power supply circuit needs to provide to the welding torch during the arc starting process.

[0052] Specifically, after detecting the arc starting signal, set the arc starting voltage for the drive circuit, and the arc starting process of welding begins. Exemplarily, the arc starting signal can be triggered when the welding torch of the MIG welder moves to a preset position. After detecting the arc starting signal, the drive circuit can generate a PWM adjustment signal in real time according to the welding feedback voltage, welding preset voltage, arc starting set voltage, current presence signal, and current feedback signal. The PWM adjustment signal can control the output current and welding voltage provided by the power supply circuit. The welding feedback voltage refers to the real-time voltage feedback value detected by the sensing device for the voltage provided by the power supply circuit to the welding torch. The welding preset voltage refers to the preset voltage value that the power supply circuit needs to provide to the welding torch during the welding process. The current presence signal refers to the signal that can reflect whether an arc is generated between the welding torch and the object to be welded. The current feedback signal refers to the real-time current feedback signal detected by the sensing device for the current provided by the power supply circuit to the welding torch.

[0053] S302. Detect the output current of the power supply circuit.

[0054] Among them, the power supply circuit refers to the circuit that provides the output current and welding voltage for the welding torch, and the output current and welding voltage it provides are adjusted according to the PWM adjustment signal.

[0055] Specifically, detecting the output current of the power supply circuit can include detecting the specific value of the output current and detecting whether there is an output current between the welding torch and the object to be welded. Exemplarily, a current sensor can be set on the connection line between the power supply circuit and the welding torch, and the output current is collected by the current sensor, and then a current presence signal and a current feedback signal are generated according to the output current. The current presence signal can reflect whether an arc is generated between the welding torch and the object to be welded, and the current feedback signal can reflect the current value formed between the welding torch and the object to be welded.

[0056] S303. When the output current of the power supply circuit is initially detected, increase the response frequency of the drive circuit from the first response frequency to the second response frequency, so that the growth rate of the output current of the power supply circuit is increased from the first rate to the second rate.

[0057] Among them, the response frequency of the drive circuit refers to the frequency at which the drive circuit generates a PWM adjustment signal based on the real-time access welding feedback voltage, welding preset voltage, arc starting set voltage, current presence signal and current feedback signal. This response frequency affects the change rate of the output current of the power supply circuit. Initially detecting means the instant when the current presence signal changes from no current to having current.

[0058] Specifically, the detection of the output current of the power supply circuit can be carried out by using a current sensor arranged on the power supply circuit line. Adjusting the response frequency of the drive circuit can be achieved by adjusting the inductance parameter in the drive circuit. When the output current of the power supply circuit is initially detected, the output current of the power supply circuit is in the rising stage. At this time, increasing the response frequency of the drive circuit from the first response frequency to the second response frequency can increase the rising slope of the current output by the power supply circuit, so that the output current rises significantly in a short time to reduce the probability of arc starting failure.

[0059] S304. Judge whether the output current reaches the current set peak value.

[0060] Among them, the current set peak value refers to the preset maximum value of the output current of the power supply circuit. Once the output current of the power supply circuit exceeds the current set peak value, it is determined that the arc starting is successful.

[0061] Specifically, the current sensor can collect the output current of the power supply circuit in real time. The judgment and processing can be implemented by using a signal processing chip, circuit or single-chip microcomputer connected to the current sensor. The signal processing chip, circuit or single-chip microcomputer can compare the relative relationship between the value of the real-time output current collected by the current sensor and the set peak current. The set peak current can be obtained through the arc starting experiment of the welding machine, and the current peak value with the highest arc starting success rate during the arc starting experiment can be set as the set peak current. When the output current of the power supply circuit reaches this set peak current, the arc starting set voltage of the drive circuit is removed, and the arc starting success rate is close to 100%. During the arc starting process, the output current of the power supply circuit has a rising stage. During this stage, the relative relationship between the output current and the set peak current is judged in real time. Once the output current reaches the set peak current, it is determined that the arc starting is successful at this time.

[0062] S305. If the output current reaches the set peak current, remove the arc starting set voltage connected to the drive circuit and restore the response frequency of the drive circuit.

[0063] Specifically, when it is detected that the output current of the power supply circuit reaches the set peak current, it can be determined that the welding machine has successfully started the arc. At this time, the arc starting can be stopped and the welding process can be entered. The method of removing the arc starting set voltage connected to the drive circuit is to turn off the input channel of the arc starting set voltage of the drive circuit. Restoring the response frequency of the drive circuit can restore the inductance parameter in the drive circuit to the preset value to ensure the stable change of the current during the welding process and improve the controllability of the current change during the welding process.

[0064] The arc starting control method of the MIG welding machine provided by the embodiment of the present invention responds to the arc starting start signal to connect the arc starting set voltage to the drive circuit to start the arc starting program. When initially detecting the output current of the power supply circuit, the response frequency of the drive circuit is increased, so that the growth rate of the output current of the power supply circuit is increased accordingly, and the energy output by the welding torch is increased in a short time, playing a role in quickly starting the arc. When the output current reaches the set peak current, the arc starting set voltage connected to the drive circuit is removed and the response frequency of the drive circuit is restored. Restoring the response frequency of the drive circuit can ensure the stable change of the current during the welding process and improve the controllability of the current change during the welding process. The arc starting control method provided by this embodiment increases the growth rate of the output current of the power supply circuit, improves the arc starting success rate and speed, and provides a more ideal arc starting effect.

[0065] Figure 4 is a schematic flow chart of an arc starting control method of a MIG welding machine provided by an embodiment of the present invention. Referring to Figure 4 , the arc starting control method of the MIG welding machine includes:

[0066] S401. Respond to the arc starting start signal and connect the arc starting set voltage to the drive circuit.

[0067] S402. Detect the output current of the power supply circuit.

[0068] Among them, steps S401 and S402 respectively correspond to the aforementioned steps S301 and S302 with the same content one by one, and will not be elaborated here.

[0069] S403. When initially detecting the output current of the power supply circuit, increase the response frequencies of the voltage PI adjustment module and the current characteristic control module from the third response frequency to the fourth response frequency, so that the growth rate of the output current of the power supply circuit increases from the first rate to the second rate.

[0070] Specifically, the drive circuit may include a current detection circuit, a voltage PI adjustment module, a current characteristic control module, a current PI adjustment circuit, and a PWM adjustment circuit. The current detection circuit is used to detect the output current and generate an output current presence signal and a current feedback signal; the voltage PI adjustment circuit is connected to the current detection circuit and is used to determine a first voltage error signal according to the arc starting set voltage and the real-time welding feedback voltage during the arc starting process, and determine a second voltage error signal according to the welding set voltage and the welding feedback voltage during the welding process; among them, during the arc starting process, the response frequency of the voltage PI adjustment circuit is the fourth response frequency when there is an output current, and the response frequency of the voltage PI adjustment circuit is the third response frequency when there is no output current, and the third response frequency is lower than the fourth response frequency; the arc characteristic control circuit is respectively connected to the voltage PI adjustment circuit and the current detection circuit and is used to perform RC filtering on the first voltage error signal and generate a first arc characteristic signal according to the filtered first voltage error signal, or perform RC filtering on the second voltage error signal and generate a second arc characteristic signal according to the filtered second voltage error signal; among them, during the arc starting process, the response frequency of the arc characteristic control circuit is the fourth response frequency when there is an output current, and the response frequency of the arc characteristic control circuit is the third response frequency when there is no output current, and the third response frequency is lower than the fourth response frequency; the current PI adjustment circuit is respectively connected to the arc characteristic control circuit and the current detection circuit and is used to determine a current error signal according to the arc characteristic signal and the current feedback signal, where the arc characteristic signal includes the first arc characteristic signal or the second arc characteristic signal; the PWM adjustment circuit is connected to the current PI adjustment circuit and is used to output a PWM adjustment signal to the power supply circuit according to the current error signal to adjust the output current and the welding voltage.

[0071] Adjusting the response frequencies of the voltage PI regulating circuit and the arc characteristic control circuit can control the on / off of the optocoupler relays in the voltage PI regulating circuit and the arc characteristic control circuit according to the presence or absence of a current signal, so as to adjust the set inductance parameter in the circuit, thereby achieving the purpose of adjusting the response frequencies of the voltage PI regulating circuit and the arc characteristic control circuit. When initially detecting the output current of the power supply circuit, the response frequencies of the voltage PI regulating circuit and the arc characteristic control circuit are increased from the third response frequency to the fourth response frequency, thereby increasing the update frequency of the first arc characteristic signal, and also increasing the rising speed of the output current of the power supply circuit.

[0072] S404. Increase the current set peak value from the first preset value to the second preset value.

[0073] Specifically, before determining whether the output current reaches the current set peak value, the current set peak value can also be increased from the first preset value to the second preset value to increase the maximum energy value output by the power supply circuit during the arc ignition process. Exemplarily, the way to adjust the current set peak value can be to adjust the resistance value of the variable resistor connected to the arc characteristic control circuit when initially detecting the output current of the power supply circuit. The first preset value is less than the second preset value. The first preset value is the set maximum value of the output current of the power supply circuit during the welding process of the welding machine, and the second preset value is the set maximum value of the output current of the power supply circuit during the arc ignition process when the output current is detected.

[0074] S405. Determine whether the output current reaches the current set peak value.

[0075] S406. If the output current reaches the current set peak value, remove the arc ignition set voltage connected to the drive circuit and restore the response frequency of the drive circuit.

[0076] Among them, steps S405 and S406 are respectively the same as the corresponding contents of the aforementioned steps S304 and S305, and will not be elaborated here.

[0077] S407. Restore the current set peak value from the second preset value to the first preset value.

[0078] Specifically, the output current reaching the current set peak value can indicate that the arc ignition of the welding machine is successful. After the output current reaches the current set peak value, the current set peak value can be restored from the second preset value to the first preset value. The first preset value can be obtained based on the welding test of the welding machine. During the welding process, controlling the output current below the first preset value can make the welding temperature stable and reduce the power supply pressure, achieving the effect of improving the welding stability. Exemplarily, similar to the way of increasing the current preset peak value, the way of reducing the current preset peak value can be to adjust the resistance value of the variable resistor connected to the arc characteristic control circuit after the output current reaches the current set peak value.

[0079] The arc starting control method of the MIG welder provided in this embodiment increases the rising speed of the output current by adjusting the response frequencies of the voltage PI adjustment module and the current characteristic control module at the initial stage of arc starting, and also increases the maximum energy output by the power supply circuit during the arc starting process by increasing the set peak value of the current, so as to improve the success rate of arc starting and thus improve the reliability of the MIG welder.

[0080] An embodiment of the present invention also provides an arc starting control device for a MIG welder. Figure 5 As a schematic structural diagram of an arc starting control device for a MIG welder provided in an embodiment of the present invention, referring to Figure 5 Figure, the arc starting control device 500 of the MIG welder includes: a voltage introduction module 501, a current detection module 502, a rate adjustment module 503, a judgment module 504, and a recovery module 505. The voltage introduction module 501 is used to respond to the arc starting signal and connect the arc starting set voltage to the drive circuit; the current detection module 502 is used to detect the output current of the power supply circuit; the rate adjustment module 503 is used to increase the response frequency of the drive circuit from the first response frequency to the second response frequency when the output current of the power supply circuit is initially detected, so that the growth rate of the output current of the power supply circuit is increased from the first rate to the second rate; the judgment module 504 is used to judge whether the output current reaches the set peak value of the current; the recovery module 505 is used to remove the arc starting set voltage of the drive circuit and restore the response frequency of the drive circuit if the output current reaches the set peak value of the current.

[0081] The arc starting control device of the MIG welder provided in this embodiment responds to the arc starting signal to connect the arc starting set voltage to the drive circuit to start the arc starting program. When the output current of the power supply circuit is initially detected, the response frequency of the drive circuit is increased, so that the growth rate of the output current of the power supply circuit is increased accordingly, and the energy output by the welding torch is increased in a short time, playing the role of quickly starting the arc. When the output current reaches the set peak value of the current, the arc starting set voltage connected to the drive circuit is removed and the response frequency of the drive circuit is restored. Restoring the response frequency of the drive circuit can ensure the stable change of the current during the welding process and improve the controllability of the current change during the welding process. The arc starting control device provided in this embodiment adopts the method of increasing the growth rate of the output current of the power supply circuit, improving the success rate and speed of arc starting, and providing a more ideal arc starting effect.

[0082] Figure 6 As a schematic structural diagram of an arc starting control device for a MIG welder provided in an embodiment of the present invention, referring to Figure 6, on the basis of the foregoing embodiments, the rate adjustment module 503 in the arc starting control device 500 of the MIG welder includes a response frequency adjustment unit 601. The response frequency adjustment unit 601 is configured to increase the response frequencies of the voltage PI adjustment module and the current characteristic control module from a third response frequency to a fourth response frequency, where the third response frequency is less than the fourth response frequency. The arc starting control device 500 of the MIG welder further includes a peak adjustment module 602. The peak adjustment module 602 is configured to increase the value of the set current peak from a first preset value to a second preset value; the recovery module 505 is further configured to restore the value of the set current peak from the second preset value to the first preset value.

[0083] The arc starting control device of the MIG welder provided in this embodiment increases the rising speed of the output current by adjusting the response frequencies of the voltage PI adjustment module and the current characteristic control module at the initial stage of arc starting, and also increases the maximum energy output by the power supply circuit during the arc starting process by increasing the set current peak, so as to improve the success rate of arc starting, thereby improving the reliability of the MIG welder.

[0084] An embodiment of the present invention further provides a drive circuit of a MIG welder. Figure 7 is a schematic structural diagram of a drive circuit of a MIG welder provided in an embodiment of the present invention. Refer to Figure 7, the drive circuit 203 of the MIG welder includes: a current detection circuit 705, a voltage PI regulation circuit 701, an arc characteristic control circuit 702, a current PI regulation circuit 703, and a PWM regulation circuit 704; the current detection circuit 705 is used to detect the output current and generate a signal I1 indicating the presence or absence of the output current and a current feedback signal I2; the voltage PI regulation circuit 701 is connected to the current detection circuit 705 and is used to determine a first voltage error signal according to the arc starting set voltage U3 and the real-time welding feedback voltage U2 during the arc starting process, and determine a second voltage error signal according to the welding set voltage U1 and the welding feedback voltage U2 during the welding process; wherein, during the arc starting process, when there is an output current, the response frequency of the voltage PI regulation circuit 701 is the fourth response frequency, and when there is no output current, the response frequency of the voltage PI regulation circuit 701 is the third response frequency, and the fourth response frequency is higher than the third response frequency. The arc characteristic control circuit 702 is respectively connected to the voltage PI regulation circuit 701 and the current detection circuit 705 and is used to generate a first arc characteristic signal according to the first voltage error signal, or generate a second arc characteristic signal according to the second voltage error signal; wherein, during the arc starting process, when there is an output current, the response frequency of the arc characteristic control circuit 702 is the fourth response frequency, and when there is no output current, the response frequency of the arc characteristic control circuit 702 is the third response frequency. The current PI regulation circuit 703 is respectively connected to the arc characteristic control circuit 702 and the current detection circuit 705 and is used to determine a current error signal according to the arc characteristic signal and the current feedback signal I2, wherein the arc characteristic signal includes the first arc characteristic signal or the second arc characteristic signal. The PWM regulation circuit 704 is connected to the current PI regulation circuit 703 and is used to output a PWM regulation signal to the power supply circuit according to the current error signal to regulate the output current and the welding voltage.

[0085] The drive circuit of the MIG welder provided in this embodiment responds to the arc starting start signal by connecting the arc starting set voltage to the drive circuit to start the arc starting program. When initially detecting the output current of the power supply circuit, the response frequency of the drive circuit is increased so that the growth rate of the output current of the power supply circuit increases accordingly, and the energy output by the welding torch is increased in a short time, playing the role of quickly starting the arc. When the output current reaches the current set peak value, the arc starting set voltage connected to the drive circuit is removed and the response frequency of the drive circuit is restored. Restoring the response frequency of the drive circuit can ensure the stable change of the current during the welding process and improve the controllability of the current change during the welding process. The drive circuit provided in this embodiment adopts the method of increasing the growth rate of the output current of the power supply circuit, improving the arc starting success rate and speed, and providing a more ideal arc starting effect.

[0086] Continue to refer to Figure 7, on the basis of the foregoing embodiments, the first arc characteristic signal output by the arc characteristic control circuit 702 in the drive circuit 203 of the MIG welder includes a current set peak value; the arc characteristic control circuit 702 is further configured to set the current set peak value to a first preset value if there is no output current during the arc starting process; if there is output current, set the current set peak value to a second preset value, where the first preset value is less than the second preset value.

[0087] The drive circuit of the MIG welder provided in this embodiment improves the rising speed of the output current by adjusting the response frequencies of the voltage PI adjustment module and the current characteristic control module at the initial stage of arc starting, and also increases the maximum energy output by the power supply circuit during the arc starting process by increasing the current set peak value, so as to improve the success rate of arc starting and thus improve the reliability of the MIG welder.

[0088] An embodiment of the present invention provides a MIG welder. Figure 8 For the structural schematic diagram of a MIG welder provided in an embodiment of the present invention, refer to Figure 8 , the MIG welder 200 includes: a welding torch 201, any one of the foregoing drive circuits 203, a power supply circuit 202, and any one of the foregoing arc starting control devices 500. Among them, the arc starting control device 500 is integrated in a processor.

[0089] Figure 9 It is a simulation schematic diagram of the welding voltage and output current of an existing MIG welder after starting to strike an arc. Figure 10 It is a simulation schematic diagram of the welding voltage and output current of a MIG welder provided in an embodiment of the present invention after starting to strike an arc. Combining Figure 9 and Figure 10 , the axis scale values of the two figures are the same, and the arc starting set voltage values provided by the two welders are the same. Figure 9 Adopt the arc starting control method described in the background technology to implement arc starting. Figure 10 The welder in Figure 3 adopts the arc starting control method in Figure 9 and Figure 10 for arc starting. It can be seen from the comparison between

[0090] Figure 11 It is a simulation schematic diagram of the welding voltage and output current of another existing MIG welder after starting to strike an arc. Figure 12 It is a simulation schematic diagram of the welding voltage and output current of another MIG welder provided in an embodiment of the present invention after starting to strike an arc. Combining Figure 11 and Figure 12, the scale values of the coordinate axes of the two figures are the same, and the arc-starting set voltage values provided by the two welding machines are the same. Figure 11 The arc-starting control method described in the background art is used to implement arc starting. Figure 12 The welding machine in Figure 4 uses the arc-starting control method in Figure 11 and Figure 12 for arc starting. It can be seen from the comparison between

[0091] that the arc-starting method in the background art makes the changes in the welding voltage U and output current I of the welding machine slow, and the arc-starting time is relatively long. However, the arc-starting method in the present application makes the changes in the welding voltage U and output current I of the welding machine faster, the set peak value of the current is high, and the arc-starting speed is increased on the basis of a relatively high arc-starting success rate.

[0092] The above products can execute the methods provided in any embodiment of the present invention, and have the corresponding functional modules and beneficial effects for executing the methods.

[0093] Note that the above is only a preferred embodiment of the present invention and the applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here, and various obvious changes, re-adjustments, combinations, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An arc starting control method for a MIG welder, characterized in that, The MIG welder includes a welding torch, a drive circuit, and a power supply circuit that is connected to the welding torch and the drive circuit and outputs an adjustable drive current. Among them, the drive circuit of the MIG welder includes a current detection circuit, a voltage PI regulation circuit, an arc characteristic control circuit, a current PI regulation circuit, and a PWM regulation circuit. The voltage PI regulation circuit is connected to the current detection circuit. The arc characteristic control circuit is respectively connected to the voltage PI regulation circuit and the current detection circuit. The current PI regulation circuit is respectively connected to the arc characteristic control circuit and the current detection circuit. The PWM regulation circuit is connected to the current PI regulation circuit. The arc starting control method of the MIG welder includes: In response to the arc starting signal, connect an arc starting set voltage to the drive circuit. Detect the output current of the power supply circuit. When initially detecting the output current of the power supply circuit, increase the response frequency of the drive circuit from a first response frequency to a second response frequency, so that the growth rate of the output current of the power supply circuit increases from a first rate to a second rate. Increase the current set peak value from a first preset value to a second preset value. Judge whether the output current reaches the current set peak value. If the output current reaches the current set peak value, remove the arc starting set voltage connected to the drive circuit, restore the current set peak value from the second preset value to the first preset value, and restore the response frequency of the drive circuit.

2. The arc starting control method of the MIG welder according to claim 1, characterized in that, The drive circuit includes a voltage PI regulation module and a current characteristic control module. Increasing the response frequency of the drive circuit from a first response frequency to a second response frequency includes: Increasing the response frequencies of the voltage PI regulation module and the current characteristic control module from a third response frequency to a fourth response frequency, where the third response frequency is less than the fourth response frequency.

3. An arc starting control device for a MIG welder, characterized in that, Includes: A voltage introduction module for connecting an arc starting set voltage to the drive circuit in response to the arc starting signal. A current detection module for detecting the output current of the power supply circuit. A rate regulation module for increasing the response frequency of the drive circuit from a first response frequency to a second response frequency when initially detecting the output current of the power supply circuit, so that the growth rate of the output current of the power supply circuit increases from a first rate to a second rate. A peak regulation module for increasing the value of the current set peak from a first preset value to a second preset value. A judgment module for judging whether the output current reaches the current set peak value. A restoration module for removing the arc starting set voltage of the drive circuit, restoring the value of the current set peak from the second preset value to the first preset value, and restoring the response frequency of the drive circuit if the output current reaches the current set peak value.

4. The arc starting control device according to claim 3, characterized in that, The rate regulation module includes: A response frequency regulation unit for increasing the response frequencies of the voltage PI regulation module and the current characteristic control module from a third response frequency to a fourth response frequency, where the third response frequency is less than the fourth response frequency.

5. A drive circuit of a MIG welder, characterized in that, Includes: A current detection circuit, a voltage PI regulation circuit, an arc characteristic control circuit, a current PI regulation circuit, and a PWM regulation circuit; The current detection circuit is used to detect the output current and generate a signal indicating the presence or absence of the output current and a current feedback signal; The voltage PI regulation circuit is connected to the current detection circuit and is used to determine a first voltage error signal according to the arc-starting set voltage and the real-time welding feedback voltage during the arc-starting process, and determine a second voltage error signal according to the welding set voltage and the welding feedback voltage during the welding process; wherein, during the arc-starting process, when there is output current, the response frequency of the voltage PI regulation circuit is the fourth response frequency, and when there is no output current, the response frequency of the voltage PI regulation circuit is the third response frequency, and the third response frequency is lower than the fourth response frequency; The arc characteristic control circuit is respectively connected to the voltage PI regulation circuit and the current detection circuit and is used to generate a first arc characteristic signal according to the first voltage error signal, or generate a second arc characteristic signal according to the second voltage error signal; wherein, during the arc-starting process, when there is output current, the response frequency of the arc characteristic control circuit is the fourth response frequency, and when there is no output current, the response frequency of the arc characteristic control circuit is the third response frequency; The current PI regulation circuit is respectively connected to the arc characteristic control circuit and the current detection circuit and is used to determine a current error signal according to the arc characteristic signal and the current feedback signal, wherein the arc characteristic signal includes the first arc characteristic signal or the second arc characteristic signal; The PWM regulation circuit is connected to the current PI regulation circuit and is used to output a PWM regulation signal to the power supply circuit according to the current error signal to regulate the output current and the welding voltage.

6. The drive circuit of the MIG welder according to claim 5, characterized in that, The first arc characteristic signal includes a set peak current; The arc characteristic control circuit is further used to set the set peak current to a first preset value if there is no output current during the arc-starting process, and set the set peak current to a second preset value if there is output current, wherein the first preset value is less than the second preset value.

7. A MIG welder, characterized in that, Comprising: A welding torch, the drive circuit according to any one of claims 5-6, a power supply circuit, and the arc-starting control device according to any one of claims 3-4.

8. The MIG welder according to claim 7, wherein, The arc-starting control device is integrated in a processor.

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