A power supply, a welding system and a control method thereof

Abstract

The application provides a power supply, a welding system and a control method thereof. The method comprises: controlling a power conversion circuit to output welding power in a plurality of pulse cycles by using a control circuit; controlling the power conversion circuit in a constant current control mode in a slow rise stage of the pulse cycle, switching the constant current control mode to a constant voltage control mode when an output current reaches a slow rise target current; controlling the power conversion circuit in the constant voltage control mode in a peak value stage of the pulse cycle, and switching the constant voltage control mode to the constant current control mode after a first preset time; and controlling the power conversion circuit in the constant current control mode in a slow drop base value stage of the pulse cycle, maintaining output when the output current reaches a slow drop target current, and switching the constant current control mode to the constant voltage control mode after a second preset time. The application can control the timing of droplet transfer during pulse welding, prevent droplet splashing and ensure arc axiality.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a power supply, a welding system, and a control method thereof. Background Technology

[0002] Existing welding systems such as Figure 1 The diagram shows a MIG welding system 10, including a power supply 12 and a wire feeder 14. The wire feeder 14 delivers power to the welding torch to perform welding operations. The power supply 12 mainly includes an output module 8 and a control circuit 22. The control circuit 22 is coupled to the output module 8 and controls the operation of the power conversion circuit during selected processes. The control circuit 22 has a user interface 10 through which these processes and corresponding welding parameters can be selected. The power supply 12 may also include a memory 11, which can be used to store processes, process parameters, system updates, and any suitable data. The wire feeder 14 may be separate from and / or integrated within the power supply 12 (e.g., contained within the housing of the power supply 12). The wire feeder 14 includes a wire feed control circuit 6, which adjusts the operation of the drive assembly 3. The wire feed control circuit 6, together with the control circuit 22, serves as the control circuit of the system 10. The control circuit may also include other control modules. The drive assembly 3 contacts the welding wire electrode 13 and feeds the welding wire electrode 13 to the welding operation. The welding wire electrode 13 is typically stored on a spool 1 within a wire feeder. The wire feeder 14 may also include one or more gas valves for providing shielding gas for the welding operation. The power supply 12 and the wire feeder 14 can operate in conjunction, thereby supplying welding wire and gas resources to the welding operation when power for welding is provided spontaneously by the welding operator (e.g., via control on the welding torch). The working cable 7 is typically clamped or coupled to the workpiece 5 in some manner to complete the circuit. During the welding operation, the entire circuit is completed by the electric arc 4.

[0003] Combination Figure 2 The diagram illustrates the pulse cycle of a prior art MIG welding system. The pulse cycle includes a gradual rise phase t1, a peak phase t2, a gradual fall phase t3, and a base phase t4. In the prior art, the control circuit 22 of the MIG welding system is specifically configured to control the output module 8 in the following manner: during the gradual rise phase t1, the output module 8 is controlled in constant current mode, and when the output voltage reaches the peak voltage, it switches to constant voltage mode; during the gradual fall phase t3, the output module 8 is controlled in constant current mode, and when the output voltage reaches the base voltage, it switches to constant voltage mode.

[0004] With the existing configuration, the MIG welding system has a large output current during the peak phase t2, during which droplet formation is completed. Afterward, the output current gradually decreases to a low level t4, during which the welding wire melts almost completely or only slightly. After t4, the system enters a gradual increase phase t1, where the output current gradually rises until the peak phase t2. Because the control circuit 22 uses a constant voltage control mode to control the output module 8 during the peak phase t2, the energy in the peak phase t2 varies with the arc length voltage, resulting in significant randomness in the droplet size and detachment timing. Therefore, droplet transition can occur at any stage of the peak phase t2, the gradual decrease phase t3, or the low level phase t4.

[0005] If droplet detachment occurs during the peak phase t2 and the first half of the descending phase t3, droplet splashing is likely to occur; if droplet detachment occurs during the second half of the descending phase t3 and the base phase, the axiality of the arc is defective. Summary of the Invention

[0006] The technical problem solved by the present invention is how to control the timing of droplet transition during pulse welding in order to prevent droplet splashing and ensure arc axiality.

[0007] To address the aforementioned technical problems, the present invention provides a method for controlling pulse welding, applicable to welding systems, wherein the welding system includes: a power supply; the power supply includes: a power conversion circuit and a control circuit; the method for controlling pulse welding includes:

[0008] The control circuit is used to control the power conversion circuit to output welding power in multiple pulse cycles, each pulse cycle including: a gradual rise phase, a peak phase, and a gradual fall base phase;

[0009] During the gradual rise phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode. When the output current reaches the target current for gradual rise, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit.

[0010] During the peak phase of the pulse cycle, the control circuit is used to control the power conversion circuit in a constant voltage control mode, and after a first preset time, the constant voltage control mode is switched to a constant current control mode to control the power conversion circuit.

[0011] During the slow-fall base value phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode. When the output current reaches the slow-fall target current, the output is maintained, and after a second preset time, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit.

[0012] Optionally, controlling the power conversion circuit in a constant current control mode using the control circuit includes: controlling the power conversion circuit based on a comparison between the output current and the target current; controlling the power conversion circuit based on the comparison between the output current and the target current includes: during the gradual rise phase, causing the target current to slope upwards to reach a peak current, and during the gradual fall phase, causing the target current to slope downwards to reach a median current.

[0013] Optionally, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on a comparison between the output voltage and the target voltage; controlling the power conversion circuit based on a comparison between the output voltage and the target voltage includes: setting the target voltage to a peak voltage during the gradual rise phase when the output current reaches the target current and during the peak phase, and scaling the target voltage downwards to reach the base voltage during the gradual fall phase.

[0014] Optionally, during the gradual rise phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes:

[0015] The output current is diverted upward from the base current to control the power conversion circuit in the constant current control mode.

[0016] Increase the output current and monitor the output voltage when the output current reaches the gradually increasing target current;

[0017] The power conversion circuit is controlled to output the output current based on a comparison between the output voltage and the peak voltage.

[0018] Optionally, during the peak phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on the peak voltage.

[0019] Optionally, the gradual reduction base value stage includes: a first gradual reduction stage, a median stage, a second gradual reduction stage, and a base value stage;

[0020] During the first descent phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode, and the output is maintained when the output current reaches the descent target current.

[0021] During the midpoint phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode, and after the second preset time, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit.

[0022] During the second descent phase of the pulse cycle, the control circuit is used to control the power conversion circuit in a constant voltage control mode.

[0023] During the base value phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant voltage control mode, and after a third preset time, the constant voltage control mode is switched to constant current control mode to control the power conversion circuit.

[0024] Optionally, in the first descent phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes:

[0025] The output current is sloping downward from the peak current to control the power conversion circuit in the constant current control mode;

[0026] Reduce the output current and monitor the output current when the output current reaches the target current for gradual reduction;

[0027] The power conversion circuit is controlled to output the output current based on a comparison between the output current and the median current.

[0028] Optionally, during the median phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes: controlling the power conversion circuit based on the median current.

[0029] Optionally, in the second descent phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes:

[0030] The output voltage is down-sloped from the median voltage to control the power conversion circuit in a constant voltage control mode.

[0031] Reduce the output voltage and monitor the output voltage when it reaches the target voltage for gradual reduction;

[0032] The power conversion circuit is controlled to output the output voltage based on the comparison between the output voltage and the base voltage.

[0033] Optionally, in the second descent phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes:

[0034] The output voltage is down-sloped from the median voltage to control the power conversion circuit in a constant voltage control mode.

[0035] Reduce the output voltage to reduce the output current, and monitor the output voltage when the output current reaches the target current for gradual reduction;

[0036] The power conversion circuit is controlled to output the output voltage based on the comparison between the output voltage and the base voltage.

[0037] Optionally, during the base phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on the base voltage.

[0038] To solve the above-mentioned technical problems, the present invention also provides a power supply, including: a power conversion circuit and a control circuit, wherein the control circuit is coupled to the power conversion circuit;

[0039] The power conversion circuit is adapted to convert the input power into welding power.

[0040] The control circuit is adapted to control the power conversion circuit to output welding power within multiple pulse cycles;

[0041] Each pulse cycle includes: a rise phase, a peak phase, and a fall-to-base phase;

[0042] During the gradual rise phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant current control mode, and when the output current reaches the gradual rise target current, the constant current control mode is switched to a constant voltage control mode to control the power conversion circuit.

[0043] During the peak phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant voltage control mode, and after a first preset time, switch the constant voltage control mode to a constant current control mode to control the power conversion circuit.

[0044] During the slow-fall base phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant current control mode. After the output current reaches the slow-fall target current, the output is maintained, and after a second preset time, the constant current control mode is switched to a constant voltage control mode to control the power conversion circuit.

[0045] To address the aforementioned technical problems, the present invention also provides a welding system, comprising: a power supply and a wire feeder as described above; the power supply is further adapted to output welding power to the wire feeder, and the wire feeder is adapted to transmit power to a welding torch to perform welding operations.

[0046] The beneficial effects of the technical solution of the present invention include at least the following:

[0047] This invention enables pulse welding of carbon steel and stainless steel welding wires, achieving droplet transfer and ensuring arc stability. By optimizing the pulse cycle of existing technologies and controlling the output current during the gradual base value stage, this invention compensates for the droplet energy in the constant voltage mode during the base value stage, making droplet transfer easier and preventing droplet spatter.

[0048] This invention improves upon existing MIG welding systems' constant voltage control throughout the base phase, overcoming the difficulty in controlling arc and droplet transfer energy. By controlling the system's output current target value and employing a more precise method to monitor the end conditions of the pulse cycle's gradual rise phase, this invention avoids errors in the peak output voltage and improves the accuracy of pulse welding control.

[0049] The technical solution of this invention further optimizes the pulse model of the slow-fall base value stage, which further includes: a first slow-fall stage, a median stage, a second slow-fall stage, and a base value stage. By adding a median stage, the system obtains an output current slightly larger than that in the base value stage (this output current is much smaller than that in the peak stage), which can appropriately compensate for the droplet energy and promote droplet detachment. By controlling the timing of droplet detachment in the median stage, droplet splashing can be reduced, the direction of droplet movement can be guaranteed, and the arc axiality can be improved.

[0050] The technical solution of this invention extends the time of the base value stage. Due to the addition of the median stage and the second descent stage, it can compensate for the change in output current when the welding extension changes. In particular, when the current decreases as the extension side length decreases, it increases the melting energy of the droplet and further enables the droplet to transition smoothly. Attached Figure Description

[0051] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0052] Figure 1 This is a schematic diagram of a conventional MIG welding system.

[0053] Figure 2 This is a schematic diagram of the pulse cycle of an existing MIG welding system.

[0054] Figure 3 A schematic diagram of the structure of a P-MIG welding system provided for the technical solution of this invention;

[0055] Figure 4 A schematic diagram of the pulse cycle of the P-MIG welding system provided for the technical solution of this invention;

[0056] Figure 5 A schematic diagram of a method for controlling pulse welding provided by the present invention;

[0057] Figure 6 This is a schematic diagram illustrating an application example of the pulse welding control method provided by the technical solution of this invention. Detailed Implementation

[0058] Compared to the present invention Figure 1 and Figure 2 The control method of the welding system shown improves the duration and output current of the pulse cycle base phase, and further triggers the pulse cycle to gradually rise to the peak phase based on the target current of the gradual rise and fall phases, then gradually falls to the median phase, and continues to gradually fall to the base phase. This invention can compensate for the droplet energy in the constant voltage control mode during pulse welding, control the timing of droplet detachment, reduce droplet spatter, and improve arc axiality.

[0059] The pulsed welding based on this invention involves welding using output power that varies substantially in pulses at a controllable frequency between a large peak value and a small base value, and the pulsed welding is performed in an arc state. The welding cycle (or pulse cycle) based on this invention includes: at least one upward transition, at least one peak value, followed by a first downward transition and at least one median value, followed by a continued downward transition and at least one base value. The welding cycle is typically on the order of milliseconds or tens of milliseconds. The welding cycle may also include other stages, and the control circuit may use a control mechanism based on the above welding cycle states, wherein in some cases, the order of the above welding cycle, such as upward transition, peak value, downward transition, median value, and base value, can be adjusted according to control requirements.

[0060] To better illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0061] Unlike existing MIG (short-circuit transfer) welding systems, the welding system of this invention is a P-MIG (droplet transfer) welding system. The P-MIG welding system can apply a large current for a short time to achieve droplet transfer and complete the peak stage of the welding cycle.

[0062] As an embodiment of the technical solution of the present invention, Figure 3 This illustrates a method that can be used in P-MIG welding system 10', different from Figure 1 The power supply 12' of the P-MIG welding system 10 shown includes an output module 8 and a control circuit 9'. The control circuit 9' is coupled to the output module 8 and controls the operation of the output module 8 during a selected process.

[0063] Specifically:

[0064] The power supply 12' can be designed to perform a variety of different welding processes. Control circuitry 9' is coupled to output module 8 and controls its operation during selected processes. For example, control circuitry 9' can provide a control signal that adjusts the conductivity of a solid-state switch in output module 8 to generate the desired power.

[0065] The power supply unit 12' may contain relevant memory (such as...) Figure 3 The memory 11' shown is used to store one or more processors to store and execute various execution processes of the power supply 12', including: constant voltage control mode, constant current control mode, pulse generation mode, cutting mode, etc.

[0066] The control circuit 9' can be connected to or has a user interface 10 to select the process and corresponding welding parameters for these modes.

[0067] In the technical solution of the present invention, the control circuit 9' can be configured to control the operation of the control output module 8 in the following manner: the control circuit 9' is adapted to control the output module 8 to output welding type power in multiple pulse cycles.

[0068] Figure 4 This diagram illustrates the waveforms of the output voltage and current of the output module 8 as it outputs welding power over time within multiple pulse cycles. Each pulse cycle includes, for example,... Figure 4 The diagram shows the gradual rise phase T1, the peak phase T2, and the gradual fall phase T3.

[0069] During the gradual rise phase T1 of the pulse cycle, the control circuit 9' is adapted to control the output module 8 in constant current control mode, and when the output current reaches a certain level... Figure 4 When the target current Ih is gradually increased as shown, the constant current control mode is switched to the constant voltage control mode to control the output module 8.

[0070] During the peak phase T2 of the pulse cycle, the control circuit 9' is adapted to control the output module 8 in constant voltage control mode, and after a first preset time, switches the constant voltage control mode to constant current control mode to control the output module 8.

[0071] During the peak phase T2 of the pulse cycle, the constant voltage control mode is switched to constant current control mode after a first preset time. Specifically, this first preset time can be set based on monitoring whether the output current reaches the peak phase current (i.e., the peak current If). After the output current reaches the peak current, the system can be configured to time and monitor whether the peak phase T2 has ended. If the peak phase T2 has ended, the description of the first preset time being satisfied is considered to be met. In this embodiment, the first preset time is in principle greater than or equal to the peak phase T2, and the gradually increasing target current Ih is less than or equal to the peak current If. The first preset time can be the time when the target voltage is set to the peak voltage, or the time when the output current reaches the peak current If (or the time when the output voltage reaches the peak voltage).

[0072] During the slow-fall base value stage T3 of the pulse cycle, the control circuit 9' is adapted to control the output module 8 in constant current control mode. When the output current reaches the slow-fall target current IL, the output is maintained, and after a second preset time, the constant current control mode is switched to constant voltage control mode to control the output module 8.

[0073] In the slow-fall base phase T3 of the pulse cycle, such as Figure 4 As shown, during the control process of the control circuit 9', the output current of the output module 8 first reaches the median current Iz through the first gradual decrease, and after the second preset time, the constant current control mode is switched to the constant voltage control mode, and then continues to reach the base current Io through the second gradual decrease, and continues to control the output module 8 in the constant voltage control mode.

[0074] In constant current control mode, during the gradual base value reduction phase T3, the output current is first reduced by lowering the target current. After the output current reaches the gradual reduction target current IL, the target current is set to the median current Iz, and the output current is maintained. The phrase "after the second preset time" refers to the period during which the target current is set to the median current Iz and the current output is maintained. In principle, the gradual reduction target current IL is greater than or equal to the median current Iz, and the second preset time is either the period during which the output current is maintained at the median current Iz or the period during which the target current is set to the median current Iz.

[0075] In constant voltage control mode, the gradual reduction base value stage T3 first reduces the voltage output by tilting the target voltage downward. When the output voltage reaches the gradual reduction target voltage UL, the target voltage is set as the base value voltage Uo. At the same time, the output current is monitored to keep the output current at the base value current Io. The entire gradual reduction base value stage T3 ends after the third preset time.

[0076] After the gradual descent base value phase T3 ends, the control circuit 9' can recalculate the parameters of the gradual rise phase T1, peak phase T2, and gradual descent base value phase T3 for the next pulse cycle under external input or internal control, and switch the control mode of the control circuit 9' to constant current control mode. The aforementioned third preset time is, in principle, the period during which the base value current Io is maintained or the target voltage is maintained at the base value voltage Uo.

[0077] More specifically, in this embodiment:

[0078] When the control circuit 9' controls the output module 8 in constant current control mode, the control circuit 9' is also adapted to: control the power conversion circuit based on the comparison between the output current of the output module 8 and the target current. For example: during the gradual rise phase T1, by causing the target current to slope upward and reach the peak current If, the output current value reaches the gradual rise target current Ih for switching control modes, and after switching to constant voltage control mode, the output current value continues to reach the peak current If; during the gradual fall phase T3, the target current is caused to slope downward and reach the median current Iz, the output current value reaches the gradual fall target current IL for maintaining the output, and the output current value is maintained at the median current Iz.

[0079] When the control circuit 9' controls the output module 8 in constant voltage control mode, the control circuit 9' is also adapted to: control the power conversion circuit based on the comparison between the output voltage of the output module 8 and the target voltage. For example: during the gradual rise phase T1 when the output current reaches the target current Ih and during the peak phase T2, the target voltage is set to the peak voltage Uf. After the period of maintaining the output current at the median current Iz at the end of the gradual fall base phase T3, the target voltage is gradually shifted downward in constant voltage control mode to reach the base voltage Uo. After the output voltage value first reaches the gradually fall target voltage UL, the target voltage is set to the base voltage Uo, and the output voltage value continues to reach the base voltage Uo.

[0080] For more specific details, please refer to [link / reference]. Figure 4 During the gradual rise phase T1 of the pulse cycle, when the control circuit 9' controls the output module 8 in constant current control mode, the control circuit 9' is also suitable for controlling the output module 8 in the following manner:

[0081] First, the output current of the power conversion circuit is gradually increased from the base current Io' of the previous pulse cycle to a constant current control mode. This constant current control mode allows the target current to be gradually increased upwards, thus achieving an upward shift of the output current from the base current Io' at the end of the previous pulse cycle.

[0082] Second, increase the output current of the power conversion circuit and monitor its output voltage when the output current reaches the gradually increasing target current Ih. Increase the output current of the power conversion circuit by gradually increasing the target current or by making the target current greater than the output current. Since the control circuit needs to switch the power conversion circuit's control mode to constant voltage control mode when the output current reaches the gradually increasing target current Ih, it is necessary to monitor its output voltage.

[0083] Third, the power conversion circuit is controlled to output the output current based on a comparison between the output voltage and the peak voltage Uf. In this process, the constant voltage control mode is switched based on the comparison between the output voltage and the peak voltage Uf, so that the output voltage reaches the target peak voltage Uf during the peak phase T2.

[0084] Therefore, when the pulse cycle enters the peak stage T2, the control circuit 9' controls the output module 8 in constant voltage control mode, and the control circuit 9' controls the power conversion circuit based on the peak voltage Uf. Specifically, it monitors the output voltage of the output module 8, sets the target voltage to the peak voltage Uf, and maintains the voltage output when the output voltage reaches the peak voltage Uf, thus completing the peak stage T2.

[0085] In this embodiment, reference continues to be made to Figure 4 The gradual decrease base value stage T3 can be further divided into: the first gradual decrease stage T30, the median stage T31, the second gradual decrease stage T32, and the base value stage T33.

[0086] More specifically, in this embodiment, further:

[0087] In the first slow-descent phase T30 of the pulse cycle, the control circuit 9' is adapted to control the output module 8 in constant current control mode, and maintains the output when the output current of the output module 8 reaches the slow-descent target current IL. The system monitors the output current of the output module 8. In the first slow-descent phase T30, the output current continues to decrease, the target current slopes downward, and when the output current reaches the slow-descent target current IL, the target current is set to the median current Iz, and the output is maintained.

[0088] Therefore, in the first descent phase T30 of the pulse cycle, the control circuit 9' can control the output module 8 in constant current control mode in the following manner:

[0089] First, the output current of output module 8 is controlled in a constant current control mode by gradually decreasing the peak current If. After the peak phase T2 ends, the control circuit 9' sets the target current to slope downwards through constant current control mode, causing the output current to gradually decrease from the peak current If, i.e., continuously reducing the output current, in order to control output module 8.

[0090] Second, the output current of output module 8 is reduced, and the output current is monitored when it reaches the target current IL. Based on the constant current control mode, the control circuit 9' sets the target current to a downward slope, causing the output current of output module 8 to continuously decrease until the output current reaches the target current IL.

[0091] Third, the output module 8 is controlled to output its output current based on a comparison between the output current of the output module 8 and the median current Iz. Based on the constant current control mode, after the output current reaches the target current IL, the control circuit 9' sets the target current of the constant current control mode to the median current Iz, and maintains the output of the median current Iz after the output current of the output module 8 reaches the median current Iz, so as to enter the median stage T31.

[0092] During the median phase T31 of the pulse cycle, the control circuit 9' is adapted to control the output module 8 in constant current control mode, and after the aforementioned second preset time, switches the constant current control mode to constant voltage control mode to control the output module 8. During the median phase T31, the system monitors the output current. When the output current reaches the median current Iz, the median phase T31 can be terminated by timing. The system presets the duration of the second preset time, starting the timing after the output current reaches the median current Iz, and after the second preset time ends, switches the constant current control mode to constant voltage control mode to control the output module 8.

[0093] Therefore, during the median phase T31 of the pulse cycle, the control circuit 9' is adapted to control the output module 8 in a constant current control mode as follows: controlling the power conversion circuit based on the median current Iz. When the output current of the output module 8 reaches the median current Iz, the system times and maintains the target current of the output module 8 at the median current Iz, and after a second preset time, the median phase T31 ends, the constant current control mode is switched to the constant voltage control mode, and the system enters the second slow-descent phase T32 of the pulse cycle.

[0094] In the second descent phase T32 of the pulse cycle, the control circuit 9' is adapted to control the power conversion circuit in a constant voltage control mode. When the median phase T31 ends, the control circuit 9' switches from a constant current control mode to a constant voltage control mode, entering the second descent phase T32. The control circuit 9' sets the target voltage in the constant voltage control mode downwards, causing the output voltage of the output module 8 to gradually decrease from the median voltage Uz. The system monitors the output voltage in the second descent phase T31. When the output voltage reaches the descent target voltage UL, the system sets the target voltage as the base voltage Uo, and maintains the output base voltage Uo while the output voltage is at the base voltage Uo, entering the base phase T33.

[0095] Therefore, in the second descent phase T32 of the pulse cycle, the control circuit 9' controls the output module 8 in a constant voltage control mode in the following manner:

[0096] First, the output voltage of output module 8 is controlled in a constant voltage control mode by gradually decreasing the voltage from the median voltage Uz downwards. The control circuit 9' sets the target voltage to a downward slope, causing the output voltage of output module 8 to gradually decrease.

[0097] Second, the output voltage is reduced and monitored when it reaches the target voltage UL. When the output voltage of output module 8 gradually decreases to the target voltage UL, control circuit 9' sets the target voltage as the base voltage Uo.

[0098] Third, the output module 8 is controlled to output its output voltage based on the comparison between the output voltage and the base voltage Uo. The control circuit 9' continuously monitors the output voltage of the output module 8. When the output voltage of the output module 8 reaches the base voltage Uo, the second descent stage T32 ends and the base stage T33 begins.

[0099] Of course, in other embodiments, the control circuit 9' can also use the following monitoring method to set the constant voltage control mode during the second descent stage T32:

[0100] When the median phase T31 ends, the control circuit 9' will set the target voltage in the constant voltage control mode to tilt downwards, causing the output voltage of the output module 8 to gradually decrease. The system will monitor the output voltage and output current in the second gradual decrease phase T31. When the output current reaches the gradual decrease target current IL2, the system will set the target voltage as the base voltage Uo, and when the output voltage is detected to be the base voltage Uo, it will maintain the output base voltage Uo and enter the base phase T33.

[0101] Therefore, in the second descent phase T32 of the pulse cycle, the control circuit 9' can also control the output module 8 in constant voltage control mode in the following manner:

[0102] First, the output voltage of output module 8 is controlled in a constant voltage control mode by gradually decreasing the voltage from the median voltage Uz downwards. The control circuit 9' sets the target voltage to a downward slope, causing the output voltage of output module 8 to gradually decrease.

[0103] Second, the output voltage is reduced to reduce the output current, and the output voltage is monitored when the output current reaches the target current IL2. As the output voltage of the output module 8 gradually decreases, the output current also gradually decreases. The output current of the output module 8 is monitored, and when the output current decreases to the target voltage UL, the control circuit 9' sets the target voltage as the base voltage Uo.

[0104] Third, the output module 8 is controlled to output its output voltage based on the comparison between the output voltage and the base voltage Uo. The control circuit 9' continuously monitors the output voltage of the output module 8. When the output voltage of the output module 8 reaches the base voltage Uo, the second descent stage T32 ends and the base stage T33 begins.

[0105] Continue to refer to Figure 4In the base value phase T33 of the pulse cycle, the control circuit 9' will continue to control the power conversion circuit in constant voltage control mode, maintaining the target voltage at the base value voltage Uo. After a third preset time, the base value phase T33 ends, and the constant voltage control mode is switched to constant current control mode to enter the gradual rise phase T1 of the next pulse cycle. In the base value phase T33 of the pulse cycle, the control circuit 9' maintains the target voltage at the base value voltage Uo, keeping the output voltage of the power conversion circuit at the base value voltage Uo and the output current at the base value current Io. Therefore, in the base value phase T33 of the pulse cycle, the control circuit 9' will control the output module 8 in constant voltage control mode based on the base value voltage Uo and the base value current Io.

[0106] Continue to refer to, for example Figure 3 The P-MIG welding system 10' shown is based on the power supply 12' provided in this embodiment. The P-MIG welding system 12' transmits the power output from the power supply 12' to the welding torch via the wire feeder 14 to perform the welding operation.

[0107] In this embodiment, the control circuit 9' may also include a user interface 10, and the power supply 12' may also include a memory 11', which can be used to store processes, process parameters, system updates, and any suitable data.

[0108] The wire feeder 14 can be separate from and / or integrated within the power supply 12'. The wire feeder 14 may include a wire feed control circuit 6, which adjusts the operation of the drive assembly 3. The wire feed control circuit 6 may be combined with the control circuit 9' as the control circuit of the output module 8.

[0109] The control circuit of this embodiment may also include other control modules. The drive assembly 3 contacts the welding wire electrode 13 and feeds the welding wire electrode 13 to the welding operation. The welding wire electrode 13 is typically stored on a reel 1 within the wire feeder. The wire feeder 14 may also include one or more gas valves for providing shielding gas for the welding operation. The power supply 12 and the wire feeder 14 can operate in coordination, thereby supplying welding wire and gas resources to the welding operation when welding power is provided spontaneously by the welding operator. The working cable 7 is typically clamped or coupled to the workpiece 5 in some manner to supplement the circuit. During the welding operation, the entire circuit is supplemented by the electric arc 4.

[0110] In the technical solution of this invention, due to Figure 4The peak phase T2 of the welding pulse, as shown, employs a constant voltage control mode. This causes the peak energy to vary with the arc length voltage, resulting in significant randomness in droplet size and detachment timing. By first reducing the current through a constant current control mode in the gradual base value phase T3 to stabilize the arc length voltage and gradually decrease the droplet energy, and then further reducing it to the base value voltage through constant voltage control mode, the welding energy is reduced, thus completing the pulse welding. This invention allows for better control of droplet transition in the welding pulse system, making the timing of droplet transition controllable.

[0111] Based on the aforementioned P-MIG welding system 10' and power supply 12', the present invention also provides a method for controlling pulse welding, applicable to pulse welding systems. A pulse welding system typically includes a power supply; the power supply typically includes a power conversion circuit and a control circuit. For example... Figure 5 As shown, the method for controlling pulse welding includes:

[0112] Step S100: The control circuit is used to control the power conversion circuit to output welding power in multiple pulse cycles. Each pulse cycle includes: a gradual rise phase, a peak phase, and a gradual fall base phase.

[0113] Step S101: During the gradual rise phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode. When the output current reaches the target current for gradual rise, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit.

[0114] Step S102: During the peak phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant voltage control mode, and after a first preset time, the constant voltage control mode is switched to constant current control mode to control the power conversion circuit.

[0115] Step S103: During the slow-fall base value stage of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode. When the output current reaches the slow-fall target current, the output is maintained, and after a second preset time, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit.

[0116] In steps S101 to S103 above, controlling the power conversion circuit in constant current control mode using the control circuit includes: controlling the power conversion circuit based on a comparison between the output current and the target current. Further, controlling the power conversion circuit based on the comparison between the output current and the target current includes: during the gradual increase phase, causing the target current to slope upwards to reach a peak current, and during the gradual decrease base phase, causing the target current to slope downwards to reach a median current.

[0117] In steps S101 to S103 above, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on a comparison between the output voltage and the target voltage. Further, controlling the power conversion circuit based on the comparison between the output voltage and the target voltage includes: setting the target voltage to a peak voltage during the gradual increase phase when the output current reaches the target current and during the peak phase; and during the gradual decrease phase, downsloping the target voltage to reach the base voltage.

[0118] During the gradual rise phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes: scaling the output current upward from the base current to control the power conversion circuit in the constant current control mode; increasing the output current and monitoring the output voltage when the output current reaches the gradually rising target current; and controlling the power conversion circuit to output the output current based on a comparison between the output voltage and the peak voltage.

[0119] During the peak phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on the peak voltage.

[0120] In step S103, the gradual descent base value stage includes: a first gradual descent stage, a median stage, a second gradual descent stage, and a base value stage. Wherein:

[0121] During the first descent phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode, and the output is maintained when the output current reaches the descent target current.

[0122] During the midpoint phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode, and after the second preset time, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit.

[0123] During the second descent phase of the pulse cycle, the control circuit is used to control the power conversion circuit in a constant voltage control mode.

[0124] During the base value phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant voltage control mode, and after a third preset time, the constant voltage control mode is switched to constant current control mode to control the power conversion circuit.

[0125] More specifically:

[0126] In the first descent phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes:

[0127] The output current is sloping downward from the peak current to control the power conversion circuit in the constant current control mode;

[0128] Reduce the output current and monitor the output current when the output current reaches the target current for gradual reduction;

[0129] The power conversion circuit is controlled to output the output current based on a comparison between the output current and the median current.

[0130] During the median phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes: controlling the power conversion circuit based on the median current.

[0131] In the second descent phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes:

[0132] The output voltage is down-sloped from the median voltage to control the power conversion circuit in a constant voltage control mode.

[0133] Reduce the output voltage and monitor the output voltage when it reaches the target voltage for gradual reduction;

[0134] The power conversion circuit is controlled to output the output voltage based on the comparison between the output voltage and the base voltage.

[0135] In other embodiments, during the second descent phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit may also include:

[0136] The output voltage is down-sloped from the median voltage to control the power conversion circuit in a constant voltage control mode.

[0137] Reduce the output voltage to reduce the output current, and monitor the output voltage when the output current reaches the target current for gradual reduction.

[0138] The power conversion circuit is controlled to output the output voltage based on the comparison between the output voltage and the base voltage.

[0139] During the base value phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on the base value voltage.

[0140] Based on this embodiment Figure 5 The method of controlling pulse welding shown is as follows: Figure 6 The illustration shows an application example of a method for controlling pulse welding, including:

[0141] Initialization phase T0: Start configuration and determine system parameters such as peak and base voltages.

[0142] Gradual increase phase T1: Constant current control mode is adopted to increase the output current. When the output current is greater than or equal to the gradual increase target current, the target voltage is set to the peak voltage, and the system control mode is switched to constant voltage control mode.

[0143] Peak phase T2: Using constant voltage control mode, calculate the output current during the peak phase, time and monitor whether the peak phase has ended; after the peak phase ends, calculate the parameters of the descent phase T3, and switch the system control mode to constant current control mode.

[0144] Gradual reduction phase T3: The constant current control mode is adopted to reduce the output current. When the output current is less than or equal to the descent target current, the output is maintained and the intermediate value phase T4 is entered.

[0145] Median stage T4: The constant current control mode is adopted to time and monitor whether the median stage has ended; when the median stage ends, the target voltage is set to the base voltage and the system control mode is switched to constant voltage control mode.

[0146] T5, the slow descent stage, adopts a constant pressure control mode. This slow descent stage T5 can compensate for the droplet energy in the constant pressure mode, compensate for current changes, ensure arc stability, make the droplet transfer easier, and result in good weld formation.

[0147] Base value stage T6: The constant voltage control mode is adopted to calculate the base value stage current; the timing and monitoring of whether the base value stage has ended are performed. After the base value stage ends, the system can automatically calculate the rise stage parameters of the next welding pulse and switch the system control mode to constant current mode.

[0148] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for controlling pulse welding, applicable to a welding system, said welding system comprising: Power supply; The power supply includes: a power conversion circuit and a control circuit; characterized in that it includes: The control circuit is used to control the power conversion circuit to output welding power in multiple pulse cycles, each pulse cycle including: a gradual rise phase, a peak phase, and a gradual fall base phase; During the gradual rise phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode. When the output current reaches the target current for gradual rise, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit. During the peak phase of the pulse cycle, the control circuit is used to control the power conversion circuit in a constant voltage control mode, and after a first preset time, the constant voltage control mode is switched to a constant current control mode to control the power conversion circuit. During the slow-fall base value phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode. When the output current reaches the slow-fall target current, the output is maintained, and after a second preset time, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit. The slow-fall base value phase includes: a first slow-fall phase, a median phase, a second slow-fall phase, and a base value phase. During the first descent phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode, and the output is maintained when the output current reaches the descent target current. During the midpoint phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant current control mode, and after the second preset time, the constant current control mode is switched to constant voltage control mode to control the power conversion circuit. During the second descent phase of the pulse cycle, the control circuit is used to control the power conversion circuit in a constant voltage control mode. During the base value phase of the pulse cycle, the control circuit is used to control the power conversion circuit in constant voltage control mode, and after a third preset time, the constant voltage control mode is switched to constant current control mode to control the power conversion circuit. In the first descent phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes: The output current is sloping downward from the peak current to control the power conversion circuit in the constant current control mode; Reduce the output current and monitor the output current when the output current reaches the target current for gradual reduction; The power conversion circuit is controlled to output the output current based on a comparison between the output current and the median current. During the median phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes: controlling the power conversion circuit based on the median current; In the second descent phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: The output voltage is down-sloped from the median voltage to control the power conversion circuit in a constant voltage control mode. Reduce the output voltage to reduce the output current, and monitor the output voltage when the output current reaches the target current for gradual reduction; The power conversion circuit is controlled to output the output voltage based on the comparison between the output voltage and the base voltage. During the base value phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on the base value voltage.

2. The method for controlling pulse welding as described in claim 1, characterized in that, The method of controlling the power conversion circuit in constant current control mode using the control circuit includes: controlling the power conversion circuit based on a comparison between the output current and the target current; during the gradual increase phase, causing the target current to slope upwards to reach the peak current; during the gradual decrease phase, causing the target current to slope downwards to reach the median current; the gradually increasing target current is less than or equal to the peak current; and the gradually decreasing target current is greater than or equal to the median current.

3. The method for controlling pulse welding as described in claim 1, characterized in that, The method of using the control circuit to control the power conversion circuit in a constant voltage control mode includes: controlling the power conversion circuit based on a comparison between the output voltage and the target voltage; the method of controlling the power conversion circuit based on a comparison between the output voltage and the target voltage includes: setting the target voltage to a peak voltage during the gradual rise phase when the output current reaches the target current and during the peak phase, and scaling the target voltage downwards to reach the base voltage during the gradual fall phase.

4. The method for controlling pulse welding as described in any one of claims 1 to 3, characterized in that, During the gradual rise phase of the pulse cycle, controlling the power conversion circuit in a constant current control mode using the control circuit includes: The output current is diverted upward from the base current to control the power conversion circuit in the constant current control mode. Increase the output current and monitor the output voltage when the output current reaches the gradually increasing target current; The power conversion circuit is controlled to output the output current based on a comparison between the output voltage and the peak voltage.

5. The method for controlling pulse welding as described in any one of claims 1 to 3, characterized in that, During the peak phase of the pulse cycle, controlling the power conversion circuit in a constant voltage control mode using the control circuit includes: controlling the power conversion circuit based on the peak voltage.

6. A power supply device, characterized in that, include: A power conversion circuit and a control circuit, wherein the control circuit is coupled to the power conversion circuit; The power conversion circuit is adapted to convert the input power into welding power. The control circuit is adapted to control the power conversion circuit to output welding power within multiple pulse cycles; Each pulse cycle includes: a rise phase, a peak phase, and a fall-to-base phase; During the gradual rise phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant current control mode, and when the output current reaches the gradual rise target current, the constant current control mode is switched to a constant voltage control mode to control the power conversion circuit. During the peak phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant voltage control mode, and after a first preset time, switch the constant voltage control mode to a constant current control mode to control the power conversion circuit. During the slow-fall base value phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant current control mode. When the output current reaches the slow-fall target current, the output is maintained, and after a second preset time, the constant current control mode is switched to a constant voltage control mode to control the power conversion circuit. The slow-fall base value phase includes: a first slow-fall phase, a median phase, a second slow-fall phase, and a base value phase. During the first descent phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant current control mode and maintain the output when the output current reaches the descent target current. During the midpoint phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant current control mode, and after the second preset time, switch the constant current control mode to a constant voltage control mode to control the power conversion circuit. During the second descent phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant voltage control mode. During the base phase of the pulse cycle, the control circuit is adapted to control the power conversion circuit in a constant voltage control mode, and after a third preset time, switch the constant voltage control mode to a constant current control mode to control the power conversion circuit. During the first descent phase of the pulse cycle, when the control circuit controls the power conversion circuit in a constant current control mode, the control circuit is further adapted to: The output current is sloping downward from the peak current to control the power conversion circuit in the constant current control mode; Reduce the output current and monitor the output current when the output current reaches the target current for gradual reduction; The power conversion circuit is controlled to output the output current based on a comparison between the output current and the median current. During the median phase of the pulse cycle, when the control circuit controls the power conversion circuit in a constant current control mode, the control circuit is also adapted to: control the power conversion circuit based on the median current; In the second descent phase of the pulse cycle, when the control circuit controls the power conversion circuit in a constant voltage control mode, the control circuit is further adapted to: The output voltage is down-sloped from the median voltage to control the power conversion circuit in a constant voltage control mode. Reduce the output voltage to reduce the output current, and monitor the output voltage when the output current reaches the target current for gradual reduction; The power conversion circuit is controlled to output the output voltage based on the comparison between the output voltage and the base voltage. During the base value phase of the pulse cycle, when the control circuit controls the power conversion circuit in a constant voltage control mode, the control circuit is also adapted to control the power conversion circuit based on the base value voltage.

7. The power supply as claimed in claim 6, characterized in that, During the gradual rise phase of the pulse cycle, when the control circuit controls the power conversion circuit in a constant current control mode, the control circuit is further adapted to: The output current is diverted upward from the base current to control the power conversion circuit in the constant current control mode. Increase the output current and monitor the output voltage when the output current reaches the gradually increasing target current; The power conversion circuit is controlled to output the output current based on a comparison between the output voltage and the peak voltage.

8. The power supply as described in claim 6, characterized in that, During the peak phase of the pulse cycle, when the control circuit controls the power conversion circuit in a constant voltage control mode, the control circuit is also adapted to control the power conversion circuit based on the peak voltage.

9. A welding system, characterized in that, include: The power supply and wire feeder as described in any one of claims 6 to 8; the power supply is further adapted to output the welding power to the wire feeder, the wire feeder being adapted to transmit power to the welding torch to perform welding operations.

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