Automatic polarity-changing five-in-one welding machine

Abstract

The invention relates to the technical field of welding machines, in particular to an automatic variable polarity five-in-one welding machine, a bridge rectifier unit is used for converting alternating current into direct current, and a PFC power factor correction unit is used for providing a stable direct current power supply with a high power factor for a subsequent circuit. The full-bridge inversion unit is used for converting the direct current output by the PFC power factor correction unit into square wave alternating current; after a panel selection signal is processed by the single chip microcomputer, an AC / DC control signal is output, the AC / DC control signal controls a relay J1A to act through a triode T50, and the machine can achieve three welding modes of DC-MMA, DC-TIG and MIG through panel selection. When alternating current is output, the two welding modes of AC-MMA and AC-TIG are achieved through panel selection, so that the defect of a single welding mode of a previous welding machine is overcome, and the requirements of various occasions are met.

Description

Technical Field

[0001] The invention relates to the technical field of welding machines, in particular to an automatic polarity-changing five-in-one welding machine. Background Art

[0002] Welding machines and cutting machines are indispensable tools in industrial manufacturing. Currently, there are mainly the following types of welding machines on the market: (1) Based on the output type, they can be divided into DC welding machines and AC welding machines; (2) Based on the use of welding machines, they can be divided into manual welding, argon arc welding, and gas shielded welding. Currently, most of the welding machines in circulation are DC welding machines (most of which use one welding method, and a few use a combination of two or three) or AC argon arc welding machines.

[0003] With the development of industry, users are more demanding that a machine can realize multiple welding functions while also having cutting functions. Traditional welding machines cannot meet this requirement and can no longer meet market demand. Summary of the invention

[0004] The main purpose of the present invention is to provide an automatic polarity-changing five-in-one welding machine to solve the problem proposed in the related art that one machine can realize multiple welding functions while also having a cutting function.

[0005] In order to achieve the above object, according to one aspect of the present invention, there is provided an automatic polarity-changing five-in-one welding machine, comprising: a bridge rectifier unit, the bridge rectifier unit being used to convert alternating current into direct current; A PFC power factor correction unit, wherein the PFC power factor correction unit is used to provide a stable, high-power-factor DC power supply for subsequent circuits; An output rectifier unit, the output rectifier unit includes an output rectifier unit A and an output rectifier unit B. The output rectifier unit A and the output rectifier unit B have the same structure and are both used to perform full-wave rectification on the alternating current to convert it into direct current. The output rectifier unit A is the rectifier part of the cutting machine and provides direct current for the cutting machine. The output rectifier unit B is the rectifier part of the welding machine and provides direct current for the welding machine. A full-bridge inverter unit, which is used to convert the direct current output by the PFC power factor correction unit into square wave alternating current; A switching circuit for a cutting machine and a welding machine, the switching circuit for the cutting machine and the welding machine comprises a power relay A1A, a secondary coil dedicated to the welding machine and a secondary coil dedicated to the cutting machine, the secondary coil dedicated to the welding machine is located in an output rectifier unit B, and the secondary coil dedicated to the cutting machine is located in an output rectifier unit A. When the power relay A1A connects the main circuit to the secondary coil dedicated to the welding machine, the current path is: flowing from the secondary coil of the transformer welding machine to the output rectifier unit B, and then flowing to the welding gun interface through the output waveform switching unit, and the welding machine starts to work; when the power relay A1A switches the main circuit to the secondary coil dedicated to the cutting machine, the current path is: flowing from the secondary coil of the transformer cutting machine to the rectifier unit A, and then flowing to the cutting gun interface through the boost circuit, and the cutting machine starts to work; An output waveform switching unit, wherein the output waveform switching unit is used to realize the switching of output AC / DC.

[0006] Further, the bridge rectifier unit includes a port P1, a diode D1, a diode D2, a diode D3 and a diode D4, the anode of the diode D1 and the cathode of the diode D2 are connected to the positive pole DC+ of the DC output, the cathode of the diode D3 and the anode of the diode D4 are connected to the negative pole DC- of the DC output, the cathode of the diode D1 and the anode of the diode D3 are connected to pin 1 of the AC input port P1, and the anode of the diode D2 and the cathode of the diode D4 are connected to pin 2 of the AC input port P1.

[0007] Further, the PFC power factor correction unit includes a PFC control circuit, an inductor LT, a field effect transistor group, a diode group, a resistor group and a capacitor group, the field effect transistor group includes a field effect transistor V8 and a field effect transistor V8-1, the diode group includes a diode D5 and a diode D6, the resistor group includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a resistor R6, and the capacitor group includes a capacitor C1, a capacitor C2 and a capacitor C5.

[0008] Furthermore, one end of the inductor LT is connected to DC+, and the other end is connected to the drain of the field effect transistor V8-1 for energy storage and filtering, the source of the field effect transistor V8-1 is connected to DC-, the drain of the field effect transistor V8 is connected between the source of the field effect transistor V8-1 and DC-, the source is grounded, and the gate is connected to the PFC control circuit through the resistor R3, the anode of the diode D5 is connected between the drain of the field effect transistor V8-1 and the inductor LT, and the cathode is connected to DC1+ for rectification, the anode of the diode D6 is connected between the drain of the field effect transistor V8 and the ground, and the cathode is connected to the line between the source of the field effect transistor V8-1 and the ground.

[0009] Further, the resistor R1 is connected between the PFC control circuit and the gate of the field effect transistor V8-1, and plays a role of voltage division and current limiting. The resistor R2 is connected between the gate of the field effect transistor V8-1 and the ground, and is used to stabilize the gate voltage. The resistor R3 is connected between the PFC control circuit and the gate of the field effect transistor V8, and plays a role of voltage division and current limiting. The resistor R4 is connected between the gate of the field effect transistor V8 and the ground, and is used to stabilize the gate voltage. The resistor R5 is connected between the cathode of the diode D6 and the ground, and plays a role of voltage division. One end of the resistor R6 is connected between the cathode of the diode D5 and DC1+, and the other end is connected to the capacitor C2, and forms an absorption circuit with the capacitor C2. The capacitor C1 is connected between the drain of the field effect transistor V8-1 and the ground, and is used for filtering. One end of the capacitor C2 is connected to the resistor R6, and the other end is connected to DC1+, and forms an absorption circuit of the diode D5 with the resistor R6. The capacitor C5 is connected between DC1+ and DC1- It plays the role of smoothing the output voltage.

[0010] Furthermore, the output rectifier unit A includes a diode D7, a diode D8, a diode D9 and a diode D10, the anode of the diode D7 is connected to the cathode of the diode D8, and the connection point is the positive electrode OUT+ of the DC output, the cathode of the diode D9 is connected to the anode of the diode D10, and the connection point is the negative electrode OUT- of the DC output, the AC input terminal ACOUT1 is connected to the cathode of the diode D7 and the anode of the diode D9, the AC input terminal ACOUT2 is connected to the anode of the diode D8 and the cathode of the diode D10, and two grounds GND are respectively connected to the line between the AC input terminal ACOUT1 and the AC input terminal ACOUT2, which act as a reference potential.

[0011] Furthermore, the full-bridge inverter unit includes a bridge structure, a transformer ZBYQ, a display panel, and an inverter. The bridge structure includes transistors Q1, Q2, Q3, and Q4. The collector of the transistor Q1 is connected to DC1+, and the emitter is connected to the collector of the transistor Q3. The collector of the transistor Q2 is connected to DC1+, and the emitter is connected to the collector of the transistor Q4. The emitter of the transistor Q3 is connected to DC1-, and the emitter of the transistor Q4 is connected to DC1-. One end of the primary winding of the transformer ZBYQ is connected to the connection point between the emitter of the transistor Q2 and the collector of the transistor Q4, and the other end is connected to the connection point between the emitter of the transistor Q1 and the collector of the transistor Q3. The secondary winding has three pins, namely ACOUT1, GND, and ACOUT2. ACOUT1 and ACOUT2 are used to output AC signals, and GND is grounded.

[0012] Furthermore, the switching circuit of the cutting machine and the welding machine also includes a first diode group and a second diode group, the first diode group includes a diode d1, a diode d2, a diode d3 and a diode d4, the second diode group includes a diode d5, a diode d6, a diode d7 and a diode d8, the diode d1 and the diode d3 are connected in series, the diode d2 and the diode d4 are connected in series, the diode d5 and the diode d7 are connected in series, and the diode d6 and the diode d8 are connected in series.

[0013] Further, the output waveform switching unit includes a transistor T50, a relay J1A, an insulated gate bipolar transistor group, a port group, a resistor component, a capacitor component, a display panel and an inverter, the insulated gate bipolar transistor group includes an insulated gate bipolar transistor IGBT1, an insulated gate bipolar transistor IGBT2, an insulated gate bipolar transistor IGBT3 and an insulated gate bipolar transistor IGBT4, the port group includes a port P2 and a port P3, the resistor component includes a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R14, a resistor R15, a resistor R16 and a resistor R129, and the capacitor component includes a capacitor C3, a capacitor C5 and a capacitor C79.

[0014] Further, the display panel is connected to the inverter through a line for inputting a selection signal, and the inverter receives the signal of the display panel. The base of the transistor T50 is connected to the resistor R129, the emitter is grounded GND, the collector is connected to the cathode of the diode D11 and one end of the capacitor C79, and the other end of the capacitor C79 is grounded. Pin 4 of the relay J1A is connected to OUT+, and pin 5 is connected to DC+. The emitter of the insulated gate bipolar transistor IGBT1 is grounded, the collector is connected to OUT+, and the base is connected to the control line through the resistor R7. The emitter of the insulated gate bipolar transistor IGBT2 is grounded, the collector is connected to DC+, and the base is connected to the control line through the resistor R8. The emitter of the insulated gate bipolar transistor IGBT3 is grounded, the collector is connected to OUT-, and the base is connected to the control line through the resistor R12. The emitter of the insulated gate bipolar transistor IGBT4 is grounded, the collector is connected to DC-, and the base is connected to the control line through the resistor R13 connected to the control line, the resistors R9, R10 and R11 are connected in parallel, the resistors R14, R15 and R16 are connected in parallel, the capacitor C3 is connected between DC + and ground, the capacitor C4 is connected between DC - and ground, all of which are used for filtering, and the port P2 and port P3 each have two pins, which are respectively connected to the circuit for external connection and signal output.

[0015] Compared with the prior art, the present invention has the following beneficial effects: the machine adopts dual voltage, the input AC voltage is rectified by the bridge rectifier unit, and then corrected by the PFC power factor, the pulsating DC voltage after rectification is converted into a relatively smooth DC, and the output is converted into a square wave through the full-bridge inverter unit output, and a low-voltage AC is output through the transformer to the secondary side, and then output after the secondary full-bridge rectification, and the output here can switch the output state through the panel selection. The output mode of the machine is selected through the panel, and the panel selection signal is processed by the single-chip microcomputer to output an AC / DC control signal, and the AC / DC control signal controls the relay J1A to act through the transistor T50 to control the connection state of the output DC bus, thereby realizing the switching of AC and DC. When the output is DC, the machine can realize three welding modes of DC-MMA, DC-TIG and MIG through the panel selection; when the output is AC, the two welding modes of AC-MMA and AC-TIG are realized through the panel selection, thereby making up for the deficiency of the single welding mode of the previous welding machine and meeting the needs of various occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural block diagram of the present invention.

[0017] Figure 2 This is a circuit diagram of the bridge rectifier unit of the present invention.

[0018] Figure 3 This is a circuit diagram of a PFC power factor correction unit of the present invention.

[0019] Figure 4 This is a circuit diagram of the full-bridge inverter unit of the present invention.

[0020] Figure 5 It is the switching circuit diagram of the cutting machine and the welding machine of the present invention.

[0021] Figure 6 This is the circuit diagram of the output rectifier unit of the present invention.

[0022] Figure 7 This is a circuit diagram of the output waveform switching unit of the present invention. DETAILED DESCRIPTION

[0023] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0024] See also Figures 1 to 7 , This embodiment provides an automatic polarity-changing five-in-one welding machine, comprising: a bridge rectifier unit, the bridge rectifier unit is used to convert alternating current into direct current; PFC power factor correction unit, the PFC power factor correction unit is used to provide a stable, high power factor DC power supply for subsequent circuits; Output rectifier unit, the output rectifier unit includes an output rectifier unit A and an output rectifier unit B. The output rectifier unit A and the output rectifier unit B have the same structure and are both used to perform full-wave rectification on the alternating current and convert it into direct current. The output rectifier unit A is the rectifier part of the cutting machine and provides direct current for the cutting machine. The output rectifier unit B is the rectifier part of the welding machine and provides direct current for the welding machine. Full-bridge inverter unit, the full-bridge inverter unit is used to convert the direct current output by the PFC power factor correction unit into square wave alternating current; The switching circuit of the cutting machine and the welding machine includes a power relay A1A, a secondary coil dedicated to the welding machine and a secondary coil dedicated to the cutting machine. The secondary coil dedicated to the welding machine is located in the output rectifier unit B, and the secondary coil dedicated to the cutting machine is located in the output rectifier unit A. When the power relay A1A connects the main circuit to the secondary coil dedicated to the welding machine, the current path is: from the secondary coil of the transformer welding machine to the output rectifier unit B, and then to the welding gun interface through the output waveform switching unit, and the welding machine starts to work; when the power relay A1A switches the main circuit to the secondary coil dedicated to the cutting machine, the current path is: from the secondary coil of the transformer cutting machine to the rectifier unit A, and then to the cutting gun interface through the boost circuit, and the cutting machine starts to work; Output waveform switching unit, the output waveform switching unit is used to realize the switching of output AC / DC.

[0025] The bridge rectifier unit includes a port P1, a diode D1, a diode D2, a diode D3 and a diode D4, an anode of the diode D1 and a cathode of the diode D2 are connected to a positive pole DC+ of a DC output, a cathode of the diode D3 and an anode of the diode D4 are connected to a negative pole DC- of a DC output, a cathode of the diode D1 and an anode of the diode D3 are connected to pin 1 of an AC input port P1, and an anode of the diode D2 and a cathode of the diode D4 are connected to pin 2 of the AC input port P1.

[0026] The main function of the bridge rectifier unit is to rectify the input 1~110V / 220V and output a pulsating DC power. In the positive half cycle of the AC, diodes D1 and D4 are turned on, and in the negative half cycle, diodes D2 and D3 are turned on, converting the input AC power into DC power with unchanged direction, thereby realizing the rectification function.

[0027] The PFC power factor correction unit includes a PFC control circuit, an inductor LT, a field effect transistor group, a diode group, a resistor group and a capacitor group. The field effect transistor group includes a field effect transistor V8 and a field effect transistor V8-1. The diode group includes a diode D5 and a diode D6. The resistor group includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a resistor R6. The capacitor group includes a capacitor C1, a capacitor C2 and a capacitor C5.

[0028] One end of the inductor LT is connected to DC+, and the other end is connected to the drain of the field effect transistor V8-1 for energy storage and filtering. The source of the field effect transistor V8-1 is connected to DC-, the drain of the field effect transistor V8 is connected between the source of the field effect transistor V8-1 and DC-, the source is grounded, and the gate is connected to the PFC control circuit through the resistor R3. The anode of the diode D5 is connected between the drain of the field effect transistor V8-1 and the inductor LT, and the cathode is connected to DC1+ for rectification. The anode of the diode D6 is connected between the drain of the field effect transistor V8 and the ground, and the cathode is connected to the line between the source of the field effect transistor V8-1 and the ground.

[0029] Resistor R1 connects the PFC control circuit and the gate of the field effect transistor V8-1, and plays the role of voltage division and current limiting. Resistor R2 is connected between the gate of the field effect transistor V8-1 and the ground, and is used to stabilize the gate voltage. Resistor R3 connects the PFC control circuit and the gate of the field effect transistor V8, and plays the role of voltage division and current limiting. Resistor R4 is connected between the gate of the field effect transistor V8 and the ground, and is used to stabilize the gate voltage. Resistor R5 is connected between the cathode of the diode D6 and the ground, and plays the role of voltage division. One end of resistor R6 is connected between the cathode of the diode D5 and DC1+, and the other end is connected to capacitor C2, and forms an absorption circuit with capacitor C2. Capacitor C1 is connected between the drain of the field effect transistor V8-1 and the ground, and is used for filtering. One end of capacitor C2 is connected to resistor R6, and the other end is connected to DC1+, and forms an absorption circuit of diode D5 with resistor R6. Capacitor C5 is connected between DC1+ and DC1-, and plays the role of smoothing the output voltage.

[0030] The main function of the PFC power factor correction unit is to achieve power factor correction. By sampling the rectified voltage, the voltage across the capacitor C5, and the current flowing through the loop, PWM modulation is achieved through the PFC control circuit, thereby driving the IGBT (V8, V8-1) to achieve power factor correction. When the IGBT is turned on, the rectified voltage is stored in the inductor LT. When the IGBT is turned off, the rectified voltage and the inductor LT energy storage inductor discharge through the diode D5 (anti-reverse diode) to charge the capacitor C5, so that the output voltage DC1 is higher than DC, achieving the effect of boosting. In the figure, capacitor C1, diode D6, and resistor R5 are the IGBT absorption circuit, resistor R1 and resistor R3 are driving resistors, and resistor R6 and capacitor C2 are the absorption circuit of diode D5.

[0031] The output rectifier unit A includes a diode D7, a diode D8, a diode D9 and a diode D10. The anode of the diode D7 is connected to the cathode of the diode D8, and the connection point is the positive electrode OUT+ of the DC output. The cathode of the diode D9 is connected to the anode of the diode D10, and the connection point is the negative electrode OUT- of the DC output. The AC input terminal ACOUT1 is connected to the cathode of the diode D7 and the anode of the diode D9. The AC input terminal ACOUT2 is connected to the anode of the diode D8 and the cathode of the diode D10. Two grounds GND are respectively connected to the line between the AC input terminal ACOUT1 and the AC input terminal ACOUT2, and play the role of reference potential.

[0032] Because the no-load voltages of the cutting machine and the welding machine are different, two sets of coils are used on the secondary side of the transformer, one set is the secondary coil of the cutting machine, and the other set is the secondary coil of the welding machine.

[0033] Rectification unit A is the rectifier part of the cutting machine. This unit converts the AC input signal into a DC signal with unchanged direction by stepping up the voltage through a transformer and performing full-wave rectification on the AC. When it is a positive square wave, D7 and D10 are turned on, and when it is a negative square wave, D8 and D9 are turned on.

[0034] The full-bridge inverter unit includes a bridge structure, a transformer ZBYQ, a display panel, and an inverter. The bridge structure includes transistors Q1, Q2, Q3, and Q4. The collector of transistor Q1 is connected to DC1+, and the emitter is connected to the collector of transistor Q3. The collector of transistor Q2 is connected to DC1+, and the emitter is connected to the collector of transistor Q4. The emitter of transistor Q3 is connected to DC1-, and the emitter of transistor Q4 is connected to DC1-. One end of the primary winding of the transformer ZBYQ is connected to the connection point between the emitter of transistor Q2 and the collector of transistor Q4, and the other end is connected to the connection point between the emitter of transistor Q1 and the collector of transistor Q3. The secondary winding has three pins, namely ACOUT1, GND, and ACOUT2. ACOUT1 and ACOUT2 are used to output AC signals, and GND is grounded.

[0035] The full-bridge inverter unit converts the voltage after PFC power factor correction into square wave AC through a full-bridge inverter; when the inverter in the control loop drives the transistor Q1 and the transistor Q4 to turn on the signal, the output is a positive square wave, and when the inverter in the control loop drives the transistor Q2 and the transistor Q3 to turn on the signal, the output is a negative square wave, and then the square wave voltage is stepped down by the transformer and output to the secondary side.

[0036] The switching circuit of the cutting machine and the welding machine also includes a first diode group and a second diode group. The first diode group includes a diode D1, a diode D2, a diode D3 and a diode D4. The second diode group includes a diode D5, a diode D6, a diode D7 and a diode D8. The diode D1 is connected in series with the diode D3, the diode D2 is connected in series with the diode D4, the diode D5 is connected in series with the diode D7, and the diode D6 is connected in series with the diode D8.

[0037] The physical path switching is achieved by controlling the on-off state of the contacts of power relay A1A. When the welding mode is selected, power relay A1A connects the main circuit to the secondary coil dedicated to the welding machine (rectifier unit B), and the output voltage is the low-voltage DC required by the welding machine (about 20-40V). When the cutting mode is selected, power relay A1A switches the main circuit to the secondary coil dedicated to the cutting machine (rectifier unit A), and the output voltage is increased to the high voltage required for plasma cutting (about 100-200V). The two sets of independent secondary coils correspond to the voltage requirements of welding and cutting respectively. Rectifier unit A (cutting) and rectifier unit B (welding) are designed with different parameters. The corresponding IGBT drive parameters and PWM control strategies are automatically matched during switching. Mode interlock protection is achieved through relay A2A to prevent misoperation.

[0038] The output waveform switching unit includes transistor T50, relay J1A, insulated gate bipolar transistor group, port group, resistor component, capacitor component, display panel and inverter, the insulated gate bipolar transistor group includes insulated gate bipolar transistor IGBT1, insulated gate bipolar transistor IGBT2, insulated gate bipolar transistor IGBT3 and insulated gate bipolar transistor IGBT4, the port group includes port P2 and port P3, the resistor component includes resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, resistor R14, resistor R15, resistor R16 and resistor R129, and the capacitor component includes capacitor C3, capacitor C5 and capacitor C79.

[0039] The display panel is connected to the inverter through a line for inputting a selection signal. The inverter receives the signal from the display panel. The base of transistor T50 is connected to resistor R129, the emitter is grounded GND, the collector is connected to the cathode of diode D11 and one end of capacitor C79, and the other end of capacitor C79 is grounded. Pin 4 of relay J1A is connected to OUT+, and pin 5 is connected to DC+. The emitter of insulated gate bipolar transistor IGBT1 is grounded, the collector is connected to OUT+, and the base is connected to the control line through resistor R7. The emitter of insulated gate bipolar transistor IGBT2 is grounded, the collector is connected to DC+, and the base is connected to the control line through resistor R8. The emitter of insulated gate bipolar transistor IGBT3 is grounded, the collector is connected to OUT-, and the base is connected to the control line through resistor R12. The emitter of insulated gate bipolar transistor IGBT4 is grounded, the collector is connected to DC-, and the base is connected to the control line through resistor R13 Connected to the control line, resistors R9, R10 and R11 are connected in parallel, resistors R14, R15 and R16 are connected in parallel, capacitor C3 is connected between DC + and ground, capacitor C4 is connected between DC - and ground, all are used for filtering, port P2 and port P3 each have two pins, which are connected to the circuit respectively for external connection and signal output.

[0040] The function of the output waveform switching unit is to realize the switching of output AC / DC. When the AC / DC selection of the panel is determined, the signal is processed by the control board and an AC / DC control signal is output. When DC is selected, the transistor T50 shown in the figure is turned on and the relay J1A is energized, so that the output is DC. When AC is selected, the transistor T50 is not turned on and the relay J1A does not operate. At this time, the AC drive output control pulse of the control circuit drives the insulated gate bipolar transistor IGBT1, the insulated gate bipolar transistor IGBT2, the insulated gate bipolar transistor IGBT3, and the insulated gate bipolar transistor IGBT4 in the figure through the driving resistor R7, the resistor R8, the resistor R12, and the resistor R13. When the insulated gate bipolar transistor IGBT1 and the insulated gate bipolar transistor IGBT2 are turned on, the output is positive. When the insulated gate bipolar transistor IGBT3 and the insulated gate bipolar transistor IGBT4 are turned on, the output is negative, so that the output is AC. As shown in the figure, resistors R9 and R14 are voltage-equalizing resistors, capacitor C3, resistor R10 and resistor R11 are absorption circuits of insulated gate bipolar transistors IGBT1 and IGBT2, and capacitor C4, resistor R15 and resistor R16 are absorption circuits of insulated gate bipolar transistors IGBT3 and IGBT4.

[0041] This machine adopts dual voltage. After the input AC voltage is rectified by the bridge rectifier unit, and then corrected by the PFC power factor, the pulsating DC voltage after rectification is converted into a relatively smooth DC. After the full-bridge inverter unit output is converted into a square wave, a low-voltage AC is output through the transformer to the secondary side, and then output after the secondary full-bridge rectification. The output here can be switched through the panel selection. The output mode of this machine is selected through the panel. The panel selection signal is processed by the single-chip microcomputer to output an AC / DC control signal. The AC / DC control signal controls the relay J1A to act through the transistor T50 to control the connection state of the output DC bus, thereby realizing the switching of AC and DC. When the output is DC, this machine can realize three welding modes of DC-MMA, DC-TIG, and MIG through the panel selection; when the output is AC, the panel selection realizes two welding modes of AC-MMA and AC-TIG, thereby making up for the shortcomings of the previous single welding mode of the welding machine and meeting the needs of various occasions.

[0042] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An automatic polarity-changing five-in-one welding machine, characterized in that: include: A bridge rectifier unit, the bridge rectifier unit is used to convert alternating current into direct current; A PFC power factor correction unit, wherein the PFC power factor correction unit is used to provide a stable, high-power-factor DC power supply for subsequent circuits; An output rectifier unit, the output rectifier unit includes an output rectifier unit A and an output rectifier unit B. The output rectifier unit A and the output rectifier unit B have the same structure and are both used to perform full-wave rectification on the alternating current to convert it into direct current. The output rectifier unit A is the rectifier part of the cutting machine and provides direct current for the cutting machine. The output rectifier unit B is the rectifier part of the welding machine and provides direct current for the welding machine. A full-bridge inverter unit, which is used to convert the direct current output by the PFC power factor correction unit into square wave alternating current; A switching circuit for a cutting machine and a welding machine, the switching circuit for the cutting machine and the welding machine comprises a power relay A1A, a secondary coil dedicated to the welding machine and a secondary coil dedicated to the cutting machine, the secondary coil dedicated to the welding machine is located in an output rectifier unit B, and the secondary coil dedicated to the cutting machine is located in an output rectifier unit A. When the power relay A1A connects the main circuit to the secondary coil dedicated to the welding machine, the current path is: from the secondary coil of the transformer welding machine to the output rectifier unit B, and then to the welding gun interface through the output waveform switching unit, and the welding machine starts to work; when the power relay A1A switches the main circuit to the secondary coil dedicated to the cutting machine, the current path is: from the secondary coil of the transformer cutting machine to the rectifier unit A, and then to the cutting gun interface through the boost circuit, and the cutting machine starts to work; An output waveform switching unit, wherein the output waveform switching unit is used to realize the switching of output AC / DC.

2. The automatic polarity changing five-in-one welding machine according to claim 1, characterized in that: The bridge rectifier unit includes a port P1, a diode D1, a diode D2, a diode D3 and a diode D4, an anode of the diode D1 and a cathode of the diode D2 are connected to a positive pole DC+ of a DC output, a cathode of the diode D3 and an anode of the diode D4 are connected to a negative pole DC- of a DC output, a cathode of the diode D1 and an anode of the diode D3 are connected to a pin 1 of an AC input port P1, and an anode of the diode D2 and a cathode of the diode D4 are connected to a pin 2 of the AC input port P1.

3. The automatic polarity changing five-in-one welding machine according to claim 1, characterized in that: The PFC power factor correction unit includes a PFC control circuit, an inductor LT, a field effect transistor group, a diode group, a resistor group and a capacitor group. The field effect transistor group includes a field effect transistor V8 and a field effect transistor V8-1. The diode group includes a diode D5 and a diode D6. The resistor group includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a resistor R6. The capacitor group includes a capacitor C1, a capacitor C2 and a capacitor C5.

4. The automatic polarity changing five-in-one welding machine according to claim 3, characterized in that: One end of the inductor LT is connected to DC+, and the other end is connected to the drain of the field effect transistor V8-1 for energy storage and filtering. The source of the field effect transistor V8-1 is connected to DC-, the drain of the field effect transistor V8 is connected between the source of the field effect transistor V8-1 and DC-, the source is grounded, and the gate is connected to the PFC control circuit through the resistor R3. The anode of the diode D5 is connected between the drain of the field effect transistor V8-1 and the inductor LT, and the cathode is connected to DC1+ for rectification. The anode of the diode D6 is connected between the drain of the field effect transistor V8 and the ground, and the cathode is connected to the line between the source of the field effect transistor V8-1 and the ground.

5. The automatic polarity changing five-in-one welding machine according to claim 3, characterized in that: The resistor R1 is connected between the PFC control circuit and the gate of the field effect transistor V8-1, and plays a role of voltage division and current limiting. The resistor R2 is connected between the gate of the field effect transistor V8-1 and the ground, and is used to stabilize the gate voltage. The resistor R3 is connected between the PFC control circuit and the gate of the field effect transistor V8, and plays a role of voltage division and current limiting. The resistor R4 is connected between the gate of the field effect transistor V8 and the ground, and is used to stabilize the gate voltage. The resistor R5 is connected between the cathode of the diode D6 and the ground, and plays a role of voltage division. One end of the resistor R6 is connected between the cathode of the diode D5 and DC1+, and the other end is connected to the capacitor C2, and forms an absorption circuit with the capacitor C2. The capacitor C1 is connected between the drain of the field effect transistor V8-1 and the ground, and is used for filtering. One end of the capacitor C2 is connected to the resistor R6, and the other end is connected to DC1+, and forms an absorption circuit of the diode D5 with the resistor R6. The capacitor C5 is connected between DC1+ and DC1- It plays the role of smoothing the output voltage.

6. The automatic polarity changing five-in-one welding machine according to claim 1, characterized in that: The output rectifier unit A includes a diode D7, a diode D8, a diode D9 and a diode D10. The anode of the diode D7 is connected to the cathode of the diode D8, and the connection point is the positive electrode OUT+ of the DC output. The cathode of the diode D9 is connected to the anode of the diode D10, and the connection point is the negative electrode OUT- of the DC output. The AC input terminal ACOUT1 is connected to the cathode of the diode D7 and the anode of the diode D9. The AC input terminal ACOUT2 is connected to the anode of the diode D8 and the cathode of the diode D10. Two grounds GND are respectively connected to the line between the AC input terminal ACOUT1 and the AC input terminal ACOUT2, and play the role of reference potential.

7. The automatic polarity changing five-in-one welding machine according to claim 1, characterized in that: The full-bridge inverter unit includes a bridge structure, a transformer ZBYQ, a display panel, and an inverter. The bridge structure includes transistors Q1, Q2, Q3, and Q4. The collector of the transistor Q1 is connected to DC1+, and the emitter is connected to the collector of the transistor Q3. The collector of the transistor Q2 is connected to DC1+, and the emitter is connected to the collector of the transistor Q4. The emitter of the transistor Q3 is connected to DC1-, and the emitter of the transistor Q4 is connected to DC1-. One end of the primary winding of the transformer ZBYQ is connected to the connection point between the emitter of the transistor Q2 and the collector of the transistor Q4, and the other end is connected to the connection point between the emitter of the transistor Q1 and the collector of the transistor Q3. The secondary winding has three pins, namely ACOUT1, GND, and ACOUT2. ACOUT1 and ACOUT2 are used to output AC signals, and GND is grounded.

8. The automatic polarity changing five-in-one welding machine according to claim 1, characterized in that: The switching circuit of the cutting machine and the welding machine also includes a first diode group and a second diode group, the first diode group includes a diode d1, a diode d2, a diode d3 and a diode d4, the second diode group includes a diode d5, a diode d6, a diode d7 and a diode d8, the diode d1 and the diode d3 are connected in series, the diode d2 and the diode d4 are connected in series, the diode d5 and the diode d7 are connected in series, and the diode d6 and the diode d8 are connected in series.

9. The automatic polarity changing five-in-one welding machine according to claim 1, characterized in that: The output waveform switching unit includes a transistor T50, a relay J1A, an insulated gate bipolar transistor group, a port group, a resistor component, a capacitor component, a display panel and an inverter. The insulated gate bipolar transistor group includes an insulated gate bipolar transistor IGBT1, an insulated gate bipolar transistor IGBT2, an insulated gate bipolar transistor IGBT3 and an insulated gate bipolar transistor IGBT4. The port group includes a port P2 and a port P3. The resistor component includes a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R14, a resistor R15, a resistor R16 and a resistor R129. The capacitor component includes a capacitor C3, a capacitor C5 and a capacitor C79.

10. The automatic polarity changing five-in-one welding machine according to claim 9, characterized in that: The display panel is connected to the inverter through a line for inputting a selection signal. The inverter receives the signal of the display panel. The base of the transistor T50 is connected to the resistor R129, the emitter is grounded GND, the collector is connected to the cathode of the diode D11 and one end of the capacitor C79, and the other end of the capacitor C79 is grounded. Pin 4 of the relay J1A is connected to OUT+, and pin 5 is connected to DC+. The emitter of the insulated gate bipolar transistor IGBT1 is grounded, the collector is connected to OUT+, and the base is connected to the control line through the resistor R7. The emitter of the insulated gate bipolar transistor IGBT2 is grounded, the collector is connected to DC+, and the base is connected to the control line through the resistor R8. The emitter of the insulated gate bipolar transistor IGBT3 is grounded, the collector is connected to OUT-, and the base is connected to the control line through the resistor R12. The emitter of the insulated gate bipolar transistor IGBT4 is grounded, the collector is connected to DC-, and the base is connected to the control line through the resistor R13 connected to the control line, the resistors R9, R10 and R11 are connected in parallel, the resistors R14, R15 and R16 are connected in parallel, the capacitor C3 is connected between DC + and ground, the capacitor C4 is connected between DC - and ground, all of which are used for filtering, and the port P2 and port P3 each have two pins, which are respectively connected to the circuit for external connection and signal output.

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