Pulse arc welding circuit and apparatus

Abstract

The application provides a pulse arc welding circuit and device, which comprises an arc module and a power supply module comprising a main power supply, an electronic switch and a control unit; wherein both ends of the main power supply are connected with the arc module, the control end of the electronic switch is connected with the control unit, and the input end and the output end of the electronic switch are both connected with the arc module; due to the parallel electronic switch bypass at the arc module, the control unit provides a control pulse to the electronic switch, so that the electronic switch shunts the current in the loop of the arc module, and then the electronic switch realizes the pulse modulation of the basic pulse provided by the main power supply, and obtains a high-frequency pulse; compared with the prior art, the application can output a high-frequency pulse, and improves the arc stability and the arc heat energy density.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pulsed arc welding, in particular to a pulsed arc welding circuit and device. BACKGROUND

[0002] At present, the pulsed arc welding method has become a common technical means for improving the arc welding process, whether in non-melting arc welding (TIG) or in the melting electrode arc welding (MIG / MAG), the pulse control will be involved. In the conventional pulse control method, the highest pulse frequency is below 200Hz, and the rising and falling speed of the pulse current is below 1000A / ms. Some basic researches on welding arc show that the current pulse above 10KHz can produce higher arc stability and arc heat energy density.

[0003] But in the existing welding power supply, it is still not possible to output the welding current pulse frequency above 10KHz from the inverter power supply itself, because at least 1M above the inverter frequency is needed, which is difficult to realize for the welding power supply such a high-power power supply at present. Moreover, even if the welding power supply itself can generate high-frequency pulse waveforms, it is also impossible to output to the welding arc. This is because the loop of the welding output cable usually has several tens to hundreds of microhenry parasitic inductance, and the pulse above 10KHz will be completely smoothed through several tens to hundreds of microhenry inductance. Because in fact, the output inductance of the 15-20KHz inverter welding machine is only 20-30 microhenry, and the pulsating direct current after secondary rectification becomes smooth direct current, therefore, how to make the welding power supply system output high-frequency pulse is a problem to be solved.

[0004] The above content is only used to assist in understanding the technical solutions of the present application, and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The main purpose of the present application is to provide a pulsed arc welding circuit and device, which aims to solve the technical problems of low pulse frequency of the welding power supply system in the prior art, resulting in poor arc stability and low arc heat energy density.

[0006] In order to achieve the above purpose, the present application provides a pulsed arc welding circuit, which comprises an arc module and a power supply module comprising a main power supply, an electronic switch and a control unit.

[0007] Wherein, the two ends of the main power supply are connected with the arc module, the control end of the electronic switch is connected with the control unit, and the input end and the output end of the electronic switch are connected with the arc module.

[0008] The control unit is used for providing control pulse for the electronic switch.

[0009] The electronic switch is configured to pulse-modulate a base pulse provided by the main power source according to the control pulse to obtain a high-frequency pulse;

[0010] The arc module is configured to perform welding according to the high-frequency pulse.

[0011] Optionally, the arc module comprises an isolation unit and a welding unit.

[0012] The isolation unit comprises a first diode.

[0013] The anode of the first diode is connected to the input end of the electronic switch, the cathode of the first diode is connected to the welding unit, and the welding unit is connected to the output end of the electronic switch.

[0014] Optionally, the welding unit comprises a welding gun and a workpiece.

[0015] The input end of the welding gun is connected to the cathode of the first diode, and one end of the workpiece is connected to the output end of the electronic switch.

[0016] Optionally, the power module further comprises an auxiliary power source and a second diode.

[0017] One end of the auxiliary power source is connected to the anode of the second diode, the cathode of the second diode is connected to the anode of the first diode, and the other end of the auxiliary power source is connected to the output end of the electronic switch.

[0018] Optionally, the first parasitic inductance is arranged in a cable connected between the second diode and the first diode, the second parasitic inductance is arranged in a cable connected between the main power source and the first diode, and the third parasitic inductance is arranged in a cable connected between the main power source and the workpiece.

[0019] Optionally, the cable connected between the electronic switch and the first diode is a coaxial cable, and the cable connected between the electronic switch and the workpiece is a coaxial cable.

[0020] Optionally, the cable connected between the electronic switch and the first diode is a twisted pair cable, and the cable connected between the electronic switch and the workpiece is a coaxial cable or a twisted pair cable.

[0021] Optionally, the control unit is further connected to the output end of the electronic switch.

[0022] In addition, in order to achieve the above-mentioned purpose, the application further provides a pulse arc welding device, which comprises the pulse arc welding circuit.

[0023] The present application provides a kind of pulse arc welding circuit, which includes: arc module and the power module comprising main power supply, electronic switch and control unit;Wherein, the two ends of the main power supply are connected with the arc module, the control end of the electronic switch is connected with the control unit, the input end and the output end of the electronic switch are connected with the arc module;The control unit is used to provide control pulse for the electronic switch;The electronic switch is used to pulse modulation according to the control pulse to the basic pulse provided by the main power supply, obtains high-frequency pulse;The arc module is used to carry out welding according to the high-frequency pulse.Due to the present application in parallel electronic switch bypass at arc module, control pulse is provided to electronic switch by control unit, to make electronic switch shunt the current of loop in arc module, and then electronic switch realizes pulse modulation to the basic pulse provided by main power supply, obtains high-frequency pulse, compared with existing, the present application can output high-frequency pulse, improves arc stability and arc heat energy density. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The circuit principle diagram of the first embodiment of the pulse arc welding circuit proposed for the embodiment of the present application;

[0025] Figure 2 The circuit principle diagram of the second embodiment of the pulse arc welding circuit proposed for the embodiment of the present application;

[0026] Figure 3 The high-frequency pulse waveform diagram with base value current of the present application;

[0027] Figure 4 The high-frequency pulse waveform diagram without base value current of the present application;

[0028] Figure 5 The basic pulse output waveform diagram of the main power supply of the present application;

[0029] Figure 6 The waveform diagram of the present application by Figure 5 The waveform diagram of high-frequency pulse amplitude modulation;

[0030] Figure 7 The waveform diagram of high-current pulse group and low-current direct current output controlled by the electronic switch of the present application;

[0031] Figure 8 The waveform diagram of the present application on the basis of base value current of auxiliary power supply intermittently superimposes high-frequency pulse group;

[0032] Figure 9 The waveform diagram of the present application on the output of main power supply is intermittently controlled by high-frequency pulse group.

[0033] Brief Description of Drawings

[0034] Reference Name Reference Name 1 Power module D1 First diode 2 Arc module D2 Second diode Vp Main power source T Welding torch Q Electronic switch W Workpiece Vk Control unit Vb Auxiliary power source

[0035] The objectives, features and advantages of the present application will be further illustrated in conjunction with the embodiments with reference to the drawings. DETAILED DESCRIPTION

[0036] It should be understood that the specific embodiments described herein are merely illustrative of the present application and do not limit the present application.

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of the present application.

[0038] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are merely used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0039] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features indicated or the number of the technical features indicated. Therefore, the adjustment with "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should still be considered that the combination of technical solutions does not exist, and is not within the scope of protection required by the present application.

[0040] Reference Figure 1 , Figure 1 The circuit principle diagram of the first embodiment of the pulse arc welding circuit proposed in the embodiments of the present application is shown in the figure.

[0041] As Figure 1 shown, the pulse arc welding circuit in the embodiments includes an arc module 2 and a power supply module 1 including a main power supply Vp, an electronic switch Q and a control unit Vk.

[0042] Wherein, both ends of the main power supply Vp are connected with the arc module 2, the control end of the electronic switch Q is connected with the control unit Vk, and the input end and the output end of the electronic switch Q are connected with the arc module 2.

[0043] It should be noted that the pulse arc welding circuit provided by the embodiment can be used in any scenario where high-frequency pulses are required to provide welding.

[0044] It can be understood that the control unit Vk is configured to provide a control pulse for the electronic switch Q, the electronic switch Q is configured to pulse-modulate a base pulse provided by the main power supply Vp according to the control pulse to obtain a high-frequency pulse, and the arc module 2 is configured to perform welding according to the high-frequency pulse.

[0045] It should be understood that the main power supply Vp described above can be a conventional welding power supply with a pulse function, which can output a base pulse, the arc module 2 described above can perform welding according to the base pulse, the electronic switch Q described above can be a high-power electronic switch Q with a switching speed of us level, and the control unit Vk described above can generate a control pulse according to specific requirements, and then control the electronic switch Q to switch at a certain frequency.

[0046] It should be further noted that when the main power supply Vp outputs the base pulse and the electronic switch Q is in an open circuit state, the main power supply Vp and the arc module 2 work in a conventional manner without high-frequency pulses.

[0047] In a specific implementation, when the main power supply Vp outputs the base pulse, the control unit Vk controls the electronic switch Q to be in a high-frequency switching state, the electronic switch Q modulates the base pulse to obtain a high-frequency pulse, the arc module 2 performs welding according to the high-frequency pulse, and the arc module 2 works in a high-frequency arc mode under the action of the electronic switch Q in the high-frequency state, the pulse frequency can reach more than 10 KHz, and the arc stability and arc heat density are improved.

[0048] Further, in order to reduce welding spatter and improve weld formation, a short-circuit transition process can be controlled by a rapid current change rate, but it is difficult to quickly reduce the welding current in the welding process, because even if the inverter primary completely closes the drive of the inverter bridge, the freewheeling effect of the internal inductance of the welding machine and the welding loop inductance will maintain the welding current to continue to flow for hundreds of microseconds, or even milliseconds. Therefore, in the embodiment, in order to achieve the above purpose, the control unit Vk is further connected to the output end of the electronic switch Q.

[0049] The arc module 2 comprises an isolation unit and a welding unit, the isolation unit comprises a first diode D1, wherein the anode of the first diode D1 is connected to the input end of the electronic switch Q (point A), the cathode of the first diode D1 is connected to the welding unit, and the welding unit is connected to the output end of the electronic switch Q. Figure 1

[0050] ​The welding unit comprises a welding torch T and a workpiece W, wherein an input end of the welding torch T is connected with a cathode of the first diode D1, and one end of the workpiece W is connected with an output end of the electronic switch Q. Figure 1 The middle B point.

[0051] It should be noted that the specific welding torch T and workpiece W are not limited in the embodiment, and the end of the welding torch T close to the workpiece W can generate an electric arc to weld the workpiece W.

[0052] It can be understood that the main power supply Vp is connected with the anode of the first diode D1 through the cables P11-P12, the main power supply Vp is connected with the workpiece W through the cables N11-N12, and the two ends of the electronic switch Q are connected with the arc module 2 through the cables K11-K12 and K21-K22 respectively.

[0053] In the specific implementation, when the electronic switch Q is turned on, the workpiece W and the welding torch T are in a short circuit state, and when the electronic switch Q is turned off, the main power supply Vp normally provides a welding current for the welding torch T. The rapid short circuit between the anode of the first diode D1 and the workpiece W is realized through the switching of the electronic switch Q, so that the current provided by the main power supply Vp for the welding torch T is rapidly reduced to zero, and then the short circuit transition process of the welding torch T is effectively controlled through the rapid current change rate, thereby reducing welding spatter and improving weld formation.

[0054] It should be emphasized that the parallel control mode of the electronic switch Q and the arc module 2 in the embodiment solves the technical difficulty that the loop current cannot be suddenly changed when there is inductance in the circuit. The current in the loop of the arc module 2 is shunted by the parallel electronic switch Q circuit, and does not cause the sudden change of the current in the loop of the main power supply Vp. Therefore, the rapid decrease of the current in the loop of the arc module 2 can be realized. When the electronic switch Q is turned off, the inductance energy storage effect of the main circuit can also promote the rapid increase of the current in the loop of the arc module 2, thereby realizing the high-frequency control effect on the welding arc current.

[0055] The arc module 2 in the embodiment works in a high-frequency arc mode under the action of the electronic switch Q in a high-frequency state. The pulse frequency can reach more than 10 KHz, which improves the arc stability and arc heat density. At the same time, the rapid short circuit between the anode of the first diode D1 and the workpiece W is realized through the switching of the electronic switch Q, so that the current provided by the main power supply Vp for the welding torch T is rapidly reduced to zero, and then the short circuit transition process of the welding torch T is effectively controlled through the rapid current change rate, thereby reducing welding spatter and improving weld formation.

[0056] Referring to Figure 2 , Figure 2 The circuit principle diagram of the second embodiment of the pulse arc welding circuit proposed in the embodiment of the application;

[0057] AsFigure 2 As shown, the power module 1 further comprises an auxiliary power supply Vb and a second diode D2;

[0058] One end of the auxiliary power supply Vb is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to the anode of the first diode D1, and the other end of the auxiliary power supply Vb is connected to the output of the electronic switch Q.

[0059] It should be noted that the above-mentioned auxiliary power supply Vb can be a conventional welding power supply with a smaller power. The above-mentioned auxiliary power supply Vb can be used to output a low current value. When the electronic switch Q shorts the welding torch T, due to the isolation effect of the first diode D1, the auxiliary power supply Vb still supplies power to the welding torch T at this time. The current at this time can be referred to as a base current. The smaller the base current, the higher the high-frequency component in the arc current, the stronger the compression effect of the high-frequency current, and the better the arc stability. Of course, the minimum value of the base current can be reduced to zero.

[0060] When the switching frequency of the electronic switch Q is higher than 10KHz, the arc can still burn stably even if the base current is zero. This is because the arc extinguishing time is extremely short. For 10KHz, the duty cycle is 50%, and the arc extinguishing time is only 50us. Within such a short time, due to the thermal inertia effect, the temperature between the welding electrode of the welding torch T and the workpiece W is still high, so that the welding electrode and the workpiece W maintain sufficient ionized atmosphere.

[0061] In a specific implementation, when the main power supply Vp outputs a welding current, the auxiliary power supply Vb outputs a low current value, and the electronic switch Q is in a high-frequency state, the welding arc system formed between the main power supply Vp and the welding torch T and the workpiece W works in a high-frequency arc mode with a base current under the action of the auxiliary power supply Vb and the electronic switch Q. The pulse frequency can be higher than 10KHz. At the same time, under the condition that the auxiliary power supply Vb is closed, the main power supply Vp and the electronic switch Q can also achieve the effect of rapidly reducing the welding current.

[0062] For the convenience of understanding, the following will be described with reference to the accompanying drawings. Figures 3 to 9 In the drawings, Figures 3 to 9 The horizontal axis in each of the drawings represents time, which is 1ms per grid, and the vertical axis represents amplitude, which is 100A per grid. Figure 3 Fig. 4 is a high-frequency pulse waveform diagram with a base current. At this time, the auxiliary power supply Vb outputs a base current, and a high-frequency pulse is superimposed on the base current. Figure 4 Fig. 5 is a high-frequency pulse waveform diagram without a base current. Figure 5 Fig. 6 is a basic pulse output waveform diagram of the main power supply Vp. The pulse frequency of the main power supply Vp can be several to several hundred hertz. Through the high-frequency switching effect of the electronic switch Q, more low-frequency pulse superimposed high-frequency pulse waveforms can be derived. Figure 6 Fig. 7 is a waveform diagram of the welding arc current.Figure 5 Waveform diagram of the amplitude modulation of the high frequency pulse, when the auxiliary power Vb is in the off state; Figure 7 Waveform diagram of the high current pulse group controlled by the electronic switch Q and the low current DC output, which is realized by the high frequency switching of the electronic switch Q working during the peak value of the main power Vp and being in the on state during the base value of the main power Vp; Figure 8 Waveform diagram of the high frequency pulse group intermittently superimposed on the base current of the auxiliary power Vb, the amplitude and width of the high frequency pulse group being controllable according to the main power Vp; Figure 9 Waveform diagram of the high frequency pulse group intermittently superimposed on the output of the main power Vp, the frequency and width of the high frequency pulse group being controllable according to the main power Vp, when the peak value and the base value of the pulse of the main power Vp are set to the same value, i.e. the numerical value of the peak value.

[0063] It is emphasized that the above combination only lists part of the waveform combination, and the present application includes the above combination, but is not limited to the above combination, and various methods of requiring rapid reduction control of the welding current also belong to the content of the present patent, for example, the control technology of requiring rapid reduction of the welding current in the short circuit transition, and the two ends of the cable K11-K12 can be used as the output of the high-precision arc voltage detection, the arc voltage signal detected by the two ends of the cable K11-K12 avoids the influence of the resistance and inductance on the welding cable, and a pure arc voltage signal can be obtained.

[0064] Further, in order to quickly re-ignite the arc, in the embodiment, the first parasitic inductance LP21P22 is arranged in the cable P21-P22 connected between the second diode D2 and the first diode D1, the second parasitic inductance LP11P12 is arranged in the cable P11-P12 connected between the main power Vp and the first diode D1, and the third parasitic inductance LN11N12 is arranged in the cable N11-N12 connected between the main power Vp and the workpiece W.

[0065] It should be noted that in the embodiment, the parasitic inductances are arranged in the above-mentioned cable P21-P22, cable P11-P12 and cable N11-N12 respectively, and as shown in the figure, Figure 2 as shown, the output inductance Lp0 exists in the main power Vp itself, the output inductance Lb0 exists in the auxiliary power Vb itself, and the cable K11-K12 and the cable K21-K22 connected between the two ends of the electronic switch Q and the arc module 2 are two special cables, the particularity of which is that the parasitic inductance is extremely small, which can be ignored compared with the parasitic inductances arranged in the above-mentioned cable P21-P22, cable P11-P12 and cable N11-N12.

[0066] It can be understood that the above-mentioned method for reducing parasitic inductance can be to use coaxial cables or twisted pairs, that is, the cable K11-K12 connected between the electronic switch Q and the first diode D1 is a coaxial cable, the cable K21-K22 connected between the electronic switch Q and the workpiece W is a coaxial cable, or the cable K11-K12 connected between the electronic switch Q and the first diode D1 is a twisted pair, the cable K21-K22 connected between the electronic switch Q and the workpiece W is a twisted pair, and currently other cables with low parasitic inductance can also be used, such as low-inductance coaxial cables, and the embodiment is not limited in this way.

[0067] In a specific implementation, since the second parasitic inductance LP11P12 and the third parasitic inductance LN11N12 in the output loop of the main power supply Vp and the output inductance Lp0 of the main power supply Vp itself exist, when the electronic switch Q is turned off, the energy storage effect of the inductance will generate a self-induced peak voltage higher than the no-load voltage of the main power supply Vp at both ends of the arc, which can help the arc to be quickly reignited.

[0068] In addition, to achieve the above-mentioned purpose, the embodiment of the present application also provides a pulse arc welding device, which is provided with the above-mentioned pulse arc welding circuit, and in the embodiment, the structure of the pulse arc welding circuit can refer to the above-mentioned embodiments, and details are not described herein.

[0069] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation obtained by using the content of the specification and the drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A pulsed arc welding circuit, characterized in that, The pulsed arc welding circuit includes: an arc module and a power module containing a main power supply, electronic switches and a control unit; Both ends of the main power supply are connected to the arc module, the control terminal of the electronic switch is connected to the control unit, and both the input and output terminals of the electronic switch are connected to the arc module. The control unit is used to provide control pulses to the electronic switch; The electronic switch is used to pulse modulate the basic pulse provided by the main power supply according to the control pulse to obtain a high-frequency pulse. The arc module is used to perform welding according to the high-frequency pulse; The arc module includes: an isolation unit and a welding unit; The isolation unit includes: a first diode; Wherein, the anode of the first diode is connected to the input terminal of the electronic switch, the cathode of the first diode is connected to the welding unit, and the welding unit is connected to the output terminal of the electronic switch; The welding unit includes: a welding torch and a workpiece; The input end of the welding torch is connected to the cathode of the first diode, and one end of the workpiece is connected to the output end of the electronic switch. The power module further includes: an auxiliary power supply and a second diode; Wherein, one end of the auxiliary power supply is connected to the anode of the second diode, the cathode of the second diode is connected to the anode of the first diode, and the other end of the auxiliary power supply is connected to the output terminal of the electronic switch; The cable connecting the second diode to the first diode contains a first parasitic inductance, the cable connecting the main power supply to the first diode contains a second parasitic inductance, and the cable connecting the main power supply to the workpiece contains a third parasitic inductance.

2. The pulsed arc welding circuit as described in claim 1, characterized in that, The cable used to connect the electronic switch and the first diode is a coaxial cable, and the cable used to connect the electronic switch and the workpiece is a coaxial cable.

3. The pulsed arc welding circuit as described in claim 1, characterized in that, The cable used to connect the electronic switch and the first diode is a twisted pair cable, and the cable used to connect the electronic switch and the workpiece is a coaxial cable or a twisted pair cable.

4. The pulsed arc welding circuit as described in claim 1, characterized in that, The control unit is also connected to the output terminal of the electronic switch.

5. A pulsed arc welding device, characterized in that, The pulsed arc welding equipment includes a pulsed arc welding circuit as described in any one of claims 1 to 4.

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