Gas saving type gas shielded welding control circuit

Abstract

A gas saving type gas shielded welding control circuit comprises a rectification power supply circuit, the rectification power supply circuit outputs direct current to a full-bridge frequency conversion circuit, a main controller drives the full-bridge frequency conversion circuit through a frequency conversion control module, the full-bridge frequency conversion circuit outputs frequency conversion alternating current to an alternating current output circuit, and the alternating current output circuit outputs alternating current. The alternating current output circuit is further connected with an alternating counting control circuit, the output end of the alternating counting control circuit is connected with a gas circuit control valve, and the gas circuit control valve is arranged on a gas supply pipeline of a welding machine protection gas gun. The device has the beneficial effects that the supply amount of protective gas can be reasonably controlled according to actual working conditions by combining the frequency control technology of the welding machine and carrying out low-cost transformation, and excessive gas waste is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of gas shielded welding, in particular to a gas-saving type gas shielded welding control circuit. Background Art

[0002] Arc welding using gas as a protective medium. It includes tungsten inert gas welding (TIG) and metal arc welding (GMAW). In the aircraft manufacturing industry, tungsten inert gas welding was first introduced to meet the needs of welding aluminum alloys, magnesium alloys, stainless steel, etc. Later, in order to overcome the shortcomings of tungsten inert gas welding, such as difficulty in welding thick weldments and low welding productivity, in the late 1940s, after a certain understanding of the form of droplet transition, metal arc welding entered the practical stage. Carbon dioxide gas shielded welding technology overcomes the disadvantage of high cost of inert gas shielded welding, so that gas shielded welding has been promoted and applied in the welding of ordinary steels such as carbon steel and low alloy steel. Later, many gas shielded welding methods such as oxidizing mixed gas shielded welding, flux-cored wire gas shielded welding, pulsed argon arc welding, gas-electric vertical welding, etc. appeared. Gas shielded welding has been promoted and applied in many industrial sectors such as aviation, aerospace, machinery manufacturing, shipbuilding, and vehicle manufacturing due to its high efficiency and energy saving. With the improvement of the automation level of welding equipment, the use of new arc welding power sources, and the promotion and application of electronic technology and intelligent control technology, the welding quality, welding productivity and stability of gas shielded welding will be significantly improved, and mixed gas shielded welding will achieve greater development.

[0003] When using pulse power, such as welding with a low-frequency pulse current of 0.5-5Hz, the heat input of the weld can be reduced, which is convenient for controlling the cooling crystallization of the weld and the depth of penetration. It is suitable for welding thin-walled components, suspended full-position welding, and base welding of thick-walled structures. If a 20kHz high-frequency pulse current is used, the arc can be straightened and stabilized, the weld metal grains can be refined, and the welding speed can be increased.

[0004] However, the prior art still has the following disadvantages: in the whole process of gas welding, the shielding gas is supplied in excess of demand, and the supply of the shielding gas is not reasonably controlled according to the actual working conditions, resulting in serious waste. Summary of the invention

[0005] The purpose of the present invention is to provide a gas-saving gas shielded welding control circuit, which can reasonably control the supply of shielding gas according to actual working conditions and avoid excessive gas waste.

[0006] The air-saving gas shielded welding control circuit includes a rectifier power supply circuit, which outputs direct current to a full-bridge frequency conversion circuit. A main controller drives the full-bridge frequency conversion circuit via a frequency conversion control module. The full-bridge frequency conversion circuit outputs frequency-converted alternating current to an alternating current output circuit. The alternating current output circuit outputs alternating current. The key point is that the alternating current output circuit is also connected to an alternating counting control circuit. The output end of the alternating counting control circuit is connected to a gas circuit control valve. The gas circuit control valve is arranged on the gas supply pipeline of the welding machine shielding gas gun.

[0007] When welding with a low-frequency pulse current of 0.5 to 5 Hz, the welding power is often proportional to the frequency, and the gas demand is also proportional. Therefore, a circuit is built to control the gas supply using the frequency to match the gas welding power, saving gas and reducing costs.

[0008] The alternating counting control circuit includes an induction coil Ls, which senses the AC output circuit and outputs an induction pulse to the alternating comparison circuit. The alternating comparison circuit extracts effective induction pulses to the counter U2. After the counter U2 counts the induction pulses, it issues a control instruction to the gas path control valve.

[0009] The induction coil Ls is physically isolated from the power supply circuit. At the same time, the effective induction pulse number is obtained and handed over to the counter U2 for statistics. After the counter U2 accumulates the statistical number, the pulse number of the control instruction is proportionally reduced to meet the effective working frequency requirements of the gas circuit control valve.

[0010] The full-bridge frequency conversion circuit is a full-bridge circuit composed of four switch tubes, and the gates of the four switch tubes are respectively connected to the four control terminal groups of the frequency conversion control module;

[0011] The two AC output terminals of the full-bridge frequency conversion circuit are connected to the AC output circuit to output a pulse current of 0.5-5 Hz.

[0012] With the help of the welding machine's own AC-DC-AC frequency conversion control technology, the pulse frequency is controllable from the root, thus meeting the needs of low-cost transformation.

[0013] The AC output circuit includes a transformer TR1, both ends of the AC input winding of the transformer TR1 are connected to the full-bridge frequency conversion circuit, the induction coil Ls is arranged next to an output end of the AC output winding of the transformer TR1, a resistor R1 is connected in series between the two ends of the induction coil Ls, one end of the induction coil Ls is grounded, the other end of the induction coil Ls is connected in series with a diode D2 and a current-limiting resistor R2 in sequence, and then connected to the positive input end of the optocoupler U1, the negative input end of the optocoupler U1 is grounded, the negative output end of the optocoupler U1 is grounded, the positive output end is connected in series with a resistor R3 and then connected to a high level, and the positive output end is connected in series with a resistor R4 to the input end of the counter U2.

[0014] The output end of the counter U2 is connected to the base of the transistor Q5, the emitter of the transistor Q5 is grounded, the collector is connected in series with the winding of the relay J, and then in series with the resistor R5 to connect to the positive power supply, and the normally open switch of the relay J is connected in series in the power supply circuit of the gas path control valve.

[0015] The isolation of optocoupler U1 and the composite drive of transistor Q5 and relay J further ensure the safe use of the circuit.

[0016] The first output terminal of the AC output winding of the transformer TR1 is connected to the anode of the diode D8a, and the second output terminal of the AC output winding of the transformer TR1 is connected to the anode of the diode D8b. The cathodes of the diodes D8a and D8b are connected in parallel and connected to the front end of the inductor L1. The rear end of the inductor L1 is the positive power supply of the load, and the positive power supply of the load is connected to the positive power supply terminal of the wire feeder and the welding gun.

[0017] On the AC output winding of the transformer TR1, a load negative power supply is provided in the middle between the first output terminal and the second output terminal, and the load negative power supply is connected to the negative power supply terminals of the wire feeder and the welding gun.

[0018] The load positive power supply is connected to the positive end of the electrolytic capacitor C8, and the negative end of the electrolytic capacitor C8 is grounded;

[0019] The load negative power supply is connected to the negative end of the electrolytic capacitor C9, and the positive end of the electrolytic capacitor C9 is grounded.

[0020] The induction coil Ls is installed near the front end of the inductor L1.

[0021] The anode of the diode D8a is connected to the resistor R8 in series, and then connected to the positive end of the electrolytic capacitor C5, and the negative end of the electrolytic capacitor C5 is connected to the cathode of the diode D8a;

[0022] The anode of the diode D8b is connected in series with a resistor R9 and then connected to the positive end of the electrolytic capacitor C6, and the negative end of the electrolytic capacitor C6 is connected to the cathode of the diode D8b.

[0023] The induction coil Ls is arranged between the resistor R8 and the electrolytic capacitor C5;

[0024] Alternatively, the induction coil Ls is arranged between the resistor R9 and the electrolytic capacitor C6.

[0025] Beneficial effect: A gas-saving gas shielded welding control circuit is provided. Combined with the welder's own frequency control technology, low-cost modification can be carried out to reasonably control the supply of shielding gas according to actual working conditions and avoid excessive gas waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the principle diagram of the welding machine frequency conversion drive;

[0027] Figure 2 It is an alternating counting control circuit;

[0028] Figure 3 It is the control principle diagram of the gas circuit control valve. DETAILED DESCRIPTION

[0029] The specific implementation manner and working principle of the present invention are further described in detail below with reference to the accompanying drawings.

[0030] Embodiment 1, as Figure 1 As shown, a gas-saving gas shielded welding control circuit, a rectifier power supply circuit, the rectifier power supply circuit outputs direct current to the full-bridge frequency conversion circuit, the main controller drives the full-bridge frequency conversion circuit through the frequency conversion control module, the full-bridge frequency conversion circuit outputs variable-frequency alternating current to the AC output circuit, and the AC output circuit outputs alternating current. It is characterized in that the AC output circuit is also connected to an alternating counting control circuit, and the output end of the alternating counting control circuit is connected to a gas circuit control valve 1, and the gas circuit control valve 1 is arranged on the gas supply pipeline of the welding machine shielding gas gun.

[0031] like Figure 2 As shown, the alternating counting control circuit includes an induction coil Ls, which senses the AC output circuit and outputs an induction pulse to the alternating comparison circuit. The alternating comparison circuit extracts the effective induction pulse to the counter U2. After the counter U2 counts the induction pulses, it issues a control instruction to the gas circuit control valve 1.

[0032] like Figure 1 As shown, the full-bridge frequency conversion circuit is a full-bridge circuit composed of four switch tubes, and the gates of the four switch tubes are respectively connected to the four-way control terminal group of the frequency conversion control module;

[0033] The two AC output terminals of the full-bridge frequency conversion circuit are connected to the AC output circuit to output a pulse current of 0.5-5 Hz.

[0034] The AC output circuit includes a transformer TR1, both ends of the AC input winding of the transformer TR1 are connected to the full-bridge frequency conversion circuit, the induction coil Ls is arranged next to an output end of the AC output winding of the transformer TR1, a resistor R1 is connected in series between the two ends of the induction coil Ls, one end of the induction coil Ls is grounded, the other end of the induction coil Ls is connected in series with a diode D2 and a current-limiting resistor R2 in sequence, and then connected to the positive input end of the optocoupler U1, the negative input end of the optocoupler U1 is grounded, the negative output end of the optocoupler U1 is grounded, the positive output end is connected in series with a resistor R3 and then connected to a high level, and the positive output end is connected in series with a resistor R4 to the input end of the counter U2.

[0035] like Figure 2 , 3As shown, the output end of the counter U2 is connected to the base of the transistor Q5, the emitter of the transistor Q5 is grounded, the collector is connected in series with the winding of the relay J, and then in series with the resistor R5 to connect to the positive power supply, and the normally open switch of the relay J is connected in series in the power supply circuit of the gas path control valve 1.

[0036] The first output terminal of the AC output winding of the transformer TR1 is connected to the anode of the diode D8a, and the second output terminal of the AC output winding of the transformer TR1 is connected to the anode of the diode D8b. The cathodes of the diodes D8a and D8b are connected in parallel and connected to the front end of the inductor L1. The rear end of the inductor L1 is the positive power supply of the load, and the positive power supply of the load is connected to the positive power supply terminal of the wire feeder and the welding gun.

[0037] On the AC output winding of the transformer TR1, a load negative power supply is provided in the middle between the first output terminal and the second output terminal, and the load negative power supply is connected to the negative power supply terminals of the wire feeder and the welding gun.

[0038] The load positive power supply is connected to the positive end of the electrolytic capacitor C8, and the negative end of the electrolytic capacitor C8 is grounded;

[0039] The load negative power supply is connected to the negative end of the electrolytic capacitor C9, and the positive end of the electrolytic capacitor C9 is grounded.

[0040] The induction coil Ls is installed near the front end of the inductor L1.

[0041] The anode of the diode D8a is connected to the resistor R8 in series, and then connected to the positive end of the electrolytic capacitor C5, and the negative end of the electrolytic capacitor C5 is connected to the cathode of the diode D8a;

[0042] The anode of the diode D8b is connected in series with a resistor R9 and then connected to the positive end of the electrolytic capacitor C6, and the negative end of the electrolytic capacitor C6 is connected to the cathode of the diode D8b.

[0043] The structures of embodiments 2 and 3 are consistent with those of embodiment 1, except that the installation positions of the induction coil Ls are different:

[0044] In the embodiment 2, the induction coil Ls is arranged between the resistor R8 and the electrolytic capacitor C5;

[0045] In the third embodiment, the induction coil Ls is arranged between the resistor R9 and the electrolytic capacitor C6.

Claims

1. A gas-saving gas shielded welding control circuit, comprising a rectifier power supply circuit, the rectifier power supply circuit outputs direct current to a full-bridge frequency conversion circuit, a main controller drives the full-bridge frequency conversion circuit via a frequency conversion control module, the full-bridge frequency conversion circuit outputs variable frequency alternating current to an alternating current output circuit, and the alternating current output circuit outputs alternating current, characterized in that: The AC output circuit is also connected to an alternating counting control circuit, the output end of which is connected to an air circuit control valve (1), which is arranged on the air supply pipeline of the welding machine shielding air gun; The alternating counting control circuit comprises an induction coil Ls, which senses the AC output circuit and outputs an induction pulse to the alternating comparison circuit. The alternating comparison circuit extracts effective induction pulses and sends them to the counter U2. After the counter U2 counts the induction pulses, it issues a control instruction to the gas path control valve (1); The full-bridge frequency conversion circuit is a full-bridge circuit composed of four switch tubes, and the gates of the four switch tubes are respectively connected to the four control terminal groups of the frequency conversion control module; The two AC output terminals of the full-bridge frequency conversion circuit are connected to the AC output circuit to output a pulse current of 0.5-5 Hz.

2. The gas-saving gas shielded welding control circuit according to claim 1 is characterized in that: The AC output circuit includes a transformer TR1, both ends of the AC input winding of the transformer TR1 are connected to the full-bridge frequency conversion circuit, the induction coil L is arranged next to an output end of the AC output winding of the transformer TR1, a resistor R1 is connected in series between both ends of the induction coil Ls, one end of the induction coil Ls is grounded, the other end of the induction coil Ls is connected in series with a diode D2 and a current-limiting resistor R2 in sequence, and then connected to the positive input end of the optocoupler U1, the negative input end of the optocoupler U1 is grounded, the negative output end of the optocoupler U1 is grounded, the positive output end is connected in series with a resistor R3 and then connected to a high level, and the positive output end is connected in series with a resistor R4 to the input end of the counter U2.

3. The gas-saving gas shielded welding control circuit according to claim 2 is characterized in that: The output end of the counter U2 is connected to the base of the transistor Q5, the emitter of the transistor Q5 is grounded, the collector is connected in series with the winding of the relay J, and then in series with the resistor R5 to connect to the positive power supply, and the normally open switch of the relay J is connected in series in the power supply circuit of the gas path control valve (1).

4. The gas-saving gas shielded welding control circuit according to claim 2, characterized in that: The first output terminal of the AC output winding of the transformer TR1 is connected to the anode of the diode D8a, and the second output terminal of the AC output winding of the transformer TR1 is connected to the anode of the diode D8b. The cathodes of the diodes D8a and D8b are connected in parallel and connected to the front end of the inductor L1. The rear end of the inductor L1 is the positive power supply of the load, and the positive power supply of the load is connected to the positive power supply terminal of the wire feeder and the welding gun. On the AC output winding of the transformer TR1, a load negative power supply is provided in the middle between the first output terminal and the second output terminal, and the load negative power supply is connected to the negative power supply terminals of the wire feeder and the welding gun.

5. The air-saving gas shielded welding control circuit according to claim 4 is characterized in that: The load positive power supply is connected to the positive end of the electrolytic capacitor C8, and the negative end of the electrolytic capacitor C8 is grounded; The load negative power supply is connected to the negative end of the electrolytic capacitor C9, and the positive end of the electrolytic capacitor C9 is grounded.

6. The gas-saving gas shielded welding control circuit according to claim 4, characterized in that: The induction coil Ls is installed near the front end of the inductor L1.

7. The air-saving gas shielded welding control circuit according to claim 4, characterized in that: The anode of the diode D8a is connected to the resistor R8 in series, and then connected to the positive end of the electrolytic capacitor C5, and the negative end of the electrolytic capacitor C5 is connected to the cathode of the diode D8a; The anode of the diode D8b is connected in series with a resistor R9 and then connected to the positive end of the electrolytic capacitor C6, and the negative end of the electrolytic capacitor C6 is connected to the cathode of the diode D8b.

8. The gas-saving gas shielded welding control circuit according to claim 7, characterized in that: The induction coil Ls is arranged between the resistor R8 and the electrolytic capacitor C5; Alternatively, the induction coil Ls is arranged between the resistor R9 and the electrolytic capacitor C6.

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