CN216177746U - Multifunctional welding machine with single-phase multi-voltage liquid crystal display and single encoder for parameter adjustment - Google Patents
Multifunctional welding machine with single-phase multi-voltage liquid crystal display and single encoder for parameter adjustment Download PDFInfo
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Abstract
The utility model discloses a multifunctional welding machine for adjusting parameters of a single-phase multi-voltage liquid crystal display single encoder. The power supply is single-phase 110-120V and 220-240V. The welding machine has three welding methods of MIG/MAG gas shielded welding, manual electric arc welding and argon arc welding, and has no air-load low-voltage output function, and the liquid crystal display and operation control circuit and the main control circuit adopt microprocessor control technology, so that the circuit is simplified, and the reliability is improved. The welding gun can adopt a European interface gas shield welding gun or a wire drawing gun for welding. And the control panel is operated by touching keys, the welding parameter is selected by keys, and the single encoder is used for digital adjustment. During gas shield welding, the 2T/4T welding gun switch operation mode, the 'test wire feeding' and the 'test gas feeding' are selected. Manual welding also allows for adjustment of the thrust current. The circuit board is designed into five blocks, each circuit board is provided with a corresponding control circuit and a control function thereof, and various anti-interference protection measures and the like are provided.
Description
Technical Field
The utility model belongs to the technical field of inverter welding machines. The multifunctional welding machine adopts single-phase 110-120V and 220-240V power supplies and has three functions of MIG/MAG gas shielded welding, manual electric arc welding and argon arc welding, and the parameters of the single-phase multi-voltage liquid crystal display single encoder are adjusted.
Background
At present, the market competition of the small-sized inversion type MIG/MAG gas shielded welding machine products is very strong, the functions and the welding performance of the welding machine are reflected, and if the welding machine can adopt a plurality of welding methods; whether the welding effect is good or not is also reflected in whether a display and operation interface is advanced or not, whether the operation and the use are convenient for a user or not, and whether the welding device has a VRD (no-load low-voltage output) and parameter unified adjusting function or not; the reliability is high, and the like, which are greatly determined by the advancement and the advantages of the technology of the control circuit of the welding machine, the appearance and the internal structural design of the product.
In markets at home and abroad, the rated current of a small IGBT inverter MIG/MAG gas shielded welding machine is generally at the level of 140-200A (the load duration is 60-15%). Most of the welding machine products are 220V-240V single-phase power supplies, and cannot be used for other power supply voltages (such as 110V-120V and 220V-240V for general use) and welding functions (such as manual welding, argon arc welding, gas shielded welding and manual welding). Meanwhile, the display and operation control circuit and the internal control circuit also adopt analog control, do not adopt a microprocessor digital control technology, and do not use a liquid crystal screen for display. The circuit of full analog control, the integrated level is low, and for the welding machine of many welding methods, the circuit seems more complicated, has reduced the reliability of circuit work. In addition, the sizes of the circuit board and the welding machine are large, and raw materials are wasted; in addition, the electromagnetic compatibility of the welding machine has no effective technical measures and cannot pass the EMC electromagnetic compatibility certification. Therefore, such products are naturally weak in market competitiveness and have a limited range of applications.
Therefore, how to adopt the double-microprocessor controller and the circuit system thereof to develop the inverter welding machine with multi-input voltage, microprocessor control liquid crystal display and touch key operation, multiple functions and high technical content has certain technical difficulty, which is also a problem to be solved by the welding machine control technology of the utility model.
SUMMERY OF THE UTILITY MODEL
The utility model relates to a multifunctional welding machine for adjusting parameters of a single-phase multi-voltage liquid crystal display single encoder. The welding machine can be used under the input power supply voltage of single phase 110-120V or 220-240V and 50 or 60Hz, and has three welding methods of MIG/MAG gas shielded welding, manual electric arc welding and argon arc welding. In addition, under the three welding methods, the VRD function is realized when the welding machine is in no-load state.
A wire feed portion of a welder, comprising: a welding wire reel shaft, a wire feeding mechanism, an European style gas shielded welding torch interface and a wire feeding control circuit part on a main control circuit board. The wire feeding mechanism adopts a support frame of the wire feeding mechanism, a plastic base plate of the wire feeding mechanism, a fixed support I of the wire feeding mechanism and a fixed support II of the wire feeding mechanism to carry out insulation isolation and fixed installation with the vertical middle partition plate and the bottom plate. The wire feeding disc shaft is arranged on the internal vertical middle partition plate. The wire feeder is close to the front panel of the welding machine. The wire feeding mechanism is correspondingly connected with an interface of a welding gun of European gas shielded welding arranged on the front panel. And during gas shield welding, the gas shield welding gun is connected with the interface of the European gas shield welding gun in a matching way. The welding wire is mounted to the wire spool. The welding wire can be sent to the wire feeding mechanism after being installed and then is conveyed to the head of the welding gun connected with the welding wire through the welding gun interface of the European gas shielded welding. The welding wire can extend out of the contact tip of the gas shield welding gun through the wire feeding wheel and the pressing wheel of the wire feeding mechanism under the control of the circuit. During gas shielded welding, the wire feeding speed of the welding wire is controlled by the circuit board and the corresponding wire feeding speed parameter. The welding current can be changed by adjusting the wire feeding speed. And a protective gas interface on the welding gun interface of the European gas shield welding is connected to the electromagnetic gas valve through a gas pipe. The shielding gas is connected into a gas input port of the electromagnetic gas valve from the outside of the welding machine. After the gas cylinder is opened, the electromagnetic gas valve can be switched on and off under the control of the welding machine circuit through operation control, so that protective gas is connected into a welding gun and flows out of the head of the welding gun, and metal protection of a welding area is realized. During manual welding and argon arc welding, the wire feeding part is not controlled.
A housing portion of a welder. Comprises a handle, a shell, a door catch, a side cover plate, a bottom plate, a front plastic panel and a rear plastic panel.
The parts installed on the plastic panel behind the welding machine mainly include: the device comprises a power switch, an input voltage change-over switch, a power supply power line and a plug thereof, a wire fixing device of the power line, a rear panel cooling fan and a fixing bracket thereof, an air connector or an air inlet nozzle of protective air and an electromagnetic air valve part. The fixing bracket of the cooling fan can be fixed on the bottom plate of the machine shell through screws, and the cooling fan is fixed on the fixing bracket through screws. The power supply line and the plug thereof are connected to a power supply grid, and an input power conversion socket is used for conversion connection when necessary. The power switch controls the on or off of the power supply of the welding machine. The cooling fan performs forced air cooling on some parts inside the welding machine. The cooling fan is positioned at the rear part of the welding machine, and cold air is fed from an air inlet hole at the rear part of the rear panel of the welding machine case. Some heating devices or parts on the upper part of the internal circuit board, such as an IGBT (insulated gate bipolar transistor), a radiator, a fast recovery diode, a radiator and the like can be well cooled. According to different requirements of welding output current and load duration rate, a cooling fan can be arranged on an inverter main circuit and a power circuit board in the welding machine. The design of the air duct and the cooling mode is beneficial to ensuring the working reliability of the welding machine circuit, and is one of the important reasons for realizing larger current and high load duration rate of the welding machine.
The parts installed on the plastic panel in front of the welding machine mainly comprise: the welding gun comprises a fixing seat of an European welding gun interface, the European welding gun interface, a black negative polarity output quick connector seat assembly, a red positive polarity output quick connector seat assembly, a welding gun polarity conversion plug and a welding cable connected with the welding gun polarity conversion plug, a wire-drawing SPOOL welding gun connecting wire socket, a liquid crystal display and operation control panel, a front panel metal small plate and a protection box of a front control panel.
In the interior of the welding machine, except for parts installed on the front panel and the rear panel, the vertical middle partition plate is fixed on the bottom plate through screws; the EMI filtering plate can be selectively used according to a manufacturing welding machine and is arranged on the vertical middle partition plate through screws; the main control board is also arranged on the vertical middle partition board through screws; the main circuit plus power supply circuit board comprises a small control board arranged on the circuit board, the small control board is used as an assembly and is fixed on a bottom plate through a support piece and screws, one side of the component is arranged facing a vertical middle partition plate, a protective polyester film is fixed on the welding surface of the circuit board, and the protective polyester film is used for protecting the circuit board; the main circuit plus power supply circuit board is also provided with a fast recovery diode and an aluminum radiator thereof, an IGBT (insulated gate bipolar transistor) tube group and an aluminum radiator thereof, a circuit board cooling fan, an inverter main transformer, a large number of electronic components and parts.
In addition, in the aspect of internal structure design of the welding machine, the left mechanical part and the right circuit board part in the welding machine are separated through the vertical middle partition plate. The right control circuit part is surrounded by a shell composed of a vertical middle partition plate, a shell, a bottom plate, a rear panel and a front panel. The welding machine can play a role in isolating large-current strong electromagnetic interference, limiting electromagnetic radiation and improving the reliability of the welding machine.
The welding machine of the utility model has two groups of output quick connector seat assemblies which are respectively used for connecting a welding clamp cable and a workpiece clamp cable during manual electric arc welding. The polarity of the connection can be determined according to the type and requirements of the welding electrode. Red, representing a positive output; black, representing negative output; during argon arc welding, the argon arc welding gun is connected to the negative polarity output quick connector seat assembly, and the positive polarity output quick connector seat assembly is connected to the workpiece to be welded. The gas pipe of the welding gun is connected to a gas supply system through a gas pipe connected to the outside; and the welding gun is connected to the European welding gun interface component during gas shielded welding. Black output quick connector mount assemblies are commonly used to connect to a workholder weld cable in a manner known as a reverse or reverse polarity connection. The polarity conversion plug is respectively connected to the positive and negative polarity ends of the output of the welding machine, so that the polarity connection mode conversion of the welding output can be realized. Whether reverse or reverse polarity or positive polarity is used depends on the type of gas shielded welding wire and the requirements of the welding process.
For the Control Circuit board part, the Circuit board is designed into five pieces, namely an EMI input filter Circuit board (EMI), a Main Circuit and Power supply (Main Circuit + Power-PCB) Circuit board, a liquid crystal display and Operation Control Circuit board (Operation + Dispaly-PCB), a solenoid valve Control and current feedback signal amplification, conversion processing Control board or Small Control board (Small-PCB) (note: the Circuit board is arranged on the Main Circuit and the Power supply Circuit board), and a Main Control Circuit board (Main Control-PCB), wherein the EMI input filter Circuit board can be selected and matched according to the requirements of EMC electromagnetic compatibility test and authentication.
The input power supply is connected to the power input end of the welding machine, and the protective grounding of the power supply system is connected with a metal frame or a shell of the welding machine. The rear panel of the welding machine is provided with a power switch. For the welder with multiple input power supply voltages, a rear panel of the welder is also provided with a power supply voltage selection change-over switch, for example, the welder with 120V/220V power supply voltage is provided with a 120V/220V power supply voltage selection switch, and a user needs to correspondingly select the power supply voltage according to the type of the power supply input voltage; at the rear stage of a power switch of the welding machine, and at the same time, in the welding machine, near the power supply input, the manufacturing of the welding machine can be carried out by selectively matching an EMI input filter circuit board (EMI) according to the requirements of EMC electromagnetic compatibility test and certification; if not, the EMI circuit board is not installed; if not, the EMI filter circuit board is not installed; then, the Power supply is connected to the Main Circuit and the Power supply (Main Circuit + Power-PCB) Circuit board, the OUTPUT positive polarity OUTPUT (+), and the negative polarity OUTPUT (-) of the Circuit board are respectively connected to the terminals of the OUTPUT positive polarity and negative polarity quick connector components installed on the front panel of the welding machine, meanwhile, the welding current conducting terminal of the MIG/MAG gas shielded welding European connector component installed on the front panel of the welding machine is connected with the polarity conversion quick plug installed on the front panel of the welding machine through the welding cable inside the welding machine, and can be respectively connected with the sockets of the OUTPUT positive polarity and negative polarity quick connector components installed on the front panel through the polarity conversion quick plug, so as to realize the conversion purpose that the conducting nozzle of the MIG/MAG gas shielded welding gun can be connected with both the OUTPUT positive polarity and the OUTPUT negative polarity, and certainly, before welding, if the MIG/MAG gas shielded welding gun outputs positive polarity, the workpiece is connected with and outputs negative polarity; if the MIG/MAG gas shield welding gun outputs a negative polarity, then the workpiece is connected to output a positive polarity. Therefore, the use requirements of different welding wire polarity selections can be met. If the welding is argon arc welding (TIG) or manual welding (MMA), the polarity conversion quick plug is not connected with the output positive and negative polarity sockets outside the welding machine, but is connected with an argon arc welding (TIG) welding gun or a manual welding (MMA) electrode holder and a workpiece according to the connection mode requirements of the two welding methods. A cooling Fan Fan of a welding machine is characterized in that two socket interfaces, namely CN5 and CN15, are arranged on a Main Circuit and a Power supply (Main Circuit + Power-PCB) Circuit board and can be used for being connected with the cooling Fan Fan; the number configuration of the cooling fans Fan can be selected according to the rated current and the load duration requirement of the welding machine, for example, for a 200A machine type, in order to ensure that the welding machine has enough current and load duration, two cooling fans Fan are required to be configured, wherein one cooling Fan is installed on the rear panel of the welding machine, and the other cooling Fan is installed on a Main Circuit and Power supply (Main Circuit + Power-PCB) Circuit board; for the model 170A or 140A, only one cooling Fan can be configured and installed on the rear panel of the welding machine, and of course, if two cooling fans Fan are still selected, the actual load duration rate of the welding machine can reach a high value; the design of double cooling fans can be selected and matched, which is beneficial to flexible matching of performance parameters when the welding machine is manufactured; the CN4 socket of the Main Circuit and Power supply (Main Circuit + Power-PCB) Circuit board is connected with the CN1 socket of the electromagnetic valve control and current feedback signal amplification and conversion processing control board or Small control board (Small-PCB) through a plug and a connecting wire thereof, and the GAS socket of the latter is connected with the electromagnetic valve in the welding machine through the plug and the connecting wire thereof; small control boards (Small-PCB) are arranged on the main circuit and the power circuit board; CN1, CN3, CN6 and CN16 sockets of a Main Circuit and a Power supply (Main Circuit + Power-PCB) Circuit board are respectively connected with CN1, CN7, CN2 and CN9 sockets of a Main Control Circuit board (Main Control-PCB) through plugs and connecting wires thereof; a CN4 socket of a Main Control circuit board (Main Control-PCB) is connected with a CN1 socket of a liquid crystal display and Operation Control circuit board (Operation + Dispaly-PCB) through a plug and a connecting wire thereof; the MOTO socket of a Main Control circuit board (Main Control-PCB) is connected with a Control line of a Wire feeder motor (Wire feeder) through a plug and a connecting Wire thereof; a GUN Switch socket of a Main Control circuit board (Main Control-PCB) is connected with a welding GUN Switch Control line of a European type welding GUN interface on a front panel of the welding machine through a plug and a connecting line thereof; an OH socket of a Main Control circuit board (Main Control-PCB) is connected with a connecting wire of an overheating protection temperature controller WKQ through a plug and a connecting wire thereof, and the overheating protection temperature controller WKQ is installed by clinging to the surface of a radiator of the IGBT; if a user does not use the European interface to connect the welding gun but uses the SPOOL wiredrawing MIG/MAG gas shield welding gun to weld, the plug of the SPOOL wiredrawing welding gun can be connected with the socket of the wiredrawing welding gun arranged above and below the front panel of the welding machine; meanwhile, a user needs to switch the MIG/SPOOL welding gun on the vertical middle partition plate into a change-over switch, namely the switch is shifted to one side of the corresponding wire drawing gun; the MIG/SPOOL socket of a Main Control circuit board (Main Control-PCB) is connected with a MIG/SPOOL welding gun access transfer switch on a vertical middle partition plate of a welding machine through a plug and a connecting wire thereof; the MIG/SPOOL welding gun is connected to the switch, not only a switching control signal line for U2, but also a control line for switching the armature of the wire feeder, namely the latter can realize the switching of the armature connection modes of the wire feeders of two welding guns; if the European-style welding gun is used, the change-over switch is arranged on one side of the European-style welding gun and is simultaneously communicated with the armature control end of the wire feeder 10; if the wire drawing gun is used, the armature control wire can be communicated to the armature control wire of the wire drawing gun corresponding to the socket below the front panel of the welding machine; the Control lines of the wire-drawing MIG/MAG gas shielded welding gun socket on the front panel are respectively connected to the motor armature voltage output line on the Main Control board (Main Control-PCB) and two ends of the Control line of the welding gun switch, and the switch of the wire-drawing gun is adopted for welding Control operation during welding; the SPOOL wire drawing type welding gun is mainly used for welding thin welding wires and aluminum welding wires, and is not easy to generate abnormal welding problems such as wire blocking or unstable wire feeding. The 120V/240V socket of the Main Control circuit board (Main Control-PCB) is connected with the 110-through 120V and 220-through 240V power supply change-over switches on the rear panel of the welding machine through the plug and the connecting wire thereof, and correspondingly inputs the voltage grade signal to the Main Control board circuit through the change-over of the switches. The circuit boards and peripheral parts thereof are electrically connected. Can meet various control requirements and state indication of three welding methods of manual welding, argon arc welding and MIG/MAG gas shielded welding.
For the display and Operation control panel (Operation + Dispaly-PCB) part of the LCD screen, the control panel is provided with an LCD screen, a key welding method selection key, a welding gun switch Operation mode selection key, a wire detection or wire test feeding/gas detection or gas test feeding selection key, a parameter option selection key and a parameter regulator when seen from the outside of the welding machine; below this liquid crystal display, be provided with: 1) a welding method selection key of gas shield welding (MIG/MAG)/argon arc welding (TIG)/manual welding (MMA), wherein the welding method selection key of gas shield welding (MIG/MAG)/argon arc welding (TIG)/manual welding (MMA) is used for selecting corresponding three welding methods, and the selected state is indicated on the liquid crystal screen through corresponding welding method symbols (such as MIG, TIG and MMA); 2) a 2T/4T gas shield welding torch switch operation mode selection key, which is used for selecting the 2T or 4T operation mode of the gas shield welding torch switch and indicating the selected state on the liquid crystal screen through corresponding symbols (such as 2T and 4T); the 2T mode is that a welding gun switch is pressed down to start gas shielded welding, and the welding is stopped when the welding gun switch is released; the 4T mode is that a welding gun switch is pressed down, gas shielded welding is started, the welding gun switch is released, welding is continuously kept, the welding gun switch is pressed down again, welding is ready to be finished, and welding is stopped when the welding gun switch is released; 3) a 'wire detection' or 'wire test feeding'/'gas detection' or 'gas test feeding' selection key, when selecting operation, the selected state can be indicated on the liquid crystal screen through corresponding 'wire detection' or 'wire test feeding'/'gas detection' or 'gas test feeding' symbols; the wire detection or wire trial feeding function can be used for detecting whether the wire feeding is normal or not in gas shielded welding (MIG/MAG), and can also be used for realizing the slow or intermittent feeding of the welding wire under the action of a control circuit in the process of installing the welding wire in the MIG/MAG, so that the welding wire can be conveniently installed to extend out of the head of the welding gun; the function of gas detection or gas test can be used for detecting whether the gas supply is normal or not in the process of gas shield welding (MIG/MAG) and can also be used for matching with the flow regulation of a gas flowmeter.
On the right side of the liquid crystal display screen, are provided with: 1) a parameter option key; 2) a parameter adjusting encoder. In the case of the selection of the manual welding (MMA) method, the adjustable parameters are the welding current (in units of A) and the thrust current, while the other welding parameters (which are set in the control software and do not require the user to adjust themselves; in the case of the selection of the argon arc welding (TIG) method, the adjustable parameters are the welding current; in the case of the selection of the gas metal arc welding (MIG/MAG) method, the adjustable parameters are the welding voltage (in units of V), the welding current (in units of A) or the wire feed speed, the inductance.
The 'option parameter' key is used for selecting the corresponding adjustable welding parameters under each welding method; and the welding parameter adjusting knob is used for adjusting the welding parameters selected by the user under each welding method.
In the liquid crystal display, the indication of the warning symbol is used for indicating whether an overheating or overcurrent state occurs; for overheating protection, the temperature relay is installed close to the surface of the IGBT radiator, and when the temperature of the radiator of the internal IGBT is too high and exceeds the action temperature of the temperature relay, an overheating phenomenon can be indicated by lightening a warning symbol under the action of the control circuit; on the other hand, the welding machine can stop welding or output current, and under the condition that the welding machine does not output current, the temperature of the IGBT radiator which generates heat can be reduced by the action of the cooling fan. When the temperature is reduced to the recovery action temperature of the thermal protector, the thermal protector recovers, the welding machine overheating phenomenon is eliminated, and the warning symbol indicates to be extinguished. Meanwhile, the welding machine can be used for welding again. The design is convenient for the selection and use of the welder operator. For overcurrent protection, if the welder detects an overcurrent phenomenon in the working process, the indication can be carried out through a warning symbol, and meanwhile, the control circuit can also close the output of the welder. At this time, the user needs to reduce the current for use, and the power switch is closed again after the power supply is closed, so that the welding machine can be used again. If the warning indicates failure to extinguish, a fault is indicated in the control circuitry of the welder.
The welding machine of the utility model with different current grades and load duration requirements can form products with different output rated currents and load duration by adjusting a small number of specification parameters of parts on the circuit board, thereby serializing the products. For example, a low-current machine type can adopt a single cooling fan configuration, and if two fans are configured, the load duration rate can be greatly improved; changing the current grade and the size of a radiator of the IGBT device; changing the model and parameters of the fast recovery diode; the specifications, parameters and the like of the inverter main transformer and the output filter reactor are changed, and series products with different specifications are easily formed. These variations, of course, aim to match the production costs of the product with the specifications and performance specifications of the respective machine. In this way, each specification type of welder can achieve optimal cost control. This enhances the market competitiveness of the developed product.
The welding machine adopts the input EMI filter circuit, other anti-interference circuits and the structural layout design of the whole machine to ensure that the welding machine has better EMC electromagnetic compatibility; a liquid crystal display and touch key operation control circuit system controlled by a microprocessor is adopted; the single encoder is used for adjusting to realize the setting of welding parameters, unified adjustment, parameter display, selection of a welding method, selection of a welding gun switch operation mode and indication of various states; by adopting the switching power supply circuit, the control circuit of the welding machine still has stable working voltage power supply within a larger input voltage variation range, thereby not only improving the network voltage fluctuation resistance of the welding machine, but also reducing the weight and the cost of the welding machine; the voltage-multiplying conversion and control circuit controlled by the microprocessor is adopted to realize the conversion and control of the multiple input voltages of the welding machine and enhance the adaptability of the welding machine to the power supply network voltage of different countries and regions; the control method adopts microprocessor-controlled welding gun switching signal detection, MIG welding wire drawing gun detection, electromagnetic gas valve control, overheating protection signal detection, current and signal detection, wire feeding action and speed setting control, output setting, PWM signal turn-off and other controls, greatly simplifies the control circuit system of the welding machine, and improves the integration level and the working reliability of the circuit; the optical coupler, the linear optical coupler and the like are adopted to electrically isolate strong current and weak current, so that the working reliability of the control circuit is further guaranteed; the wire feeding speed is controlled by armature voltage negative feedback and current positive feedback or compensation, so that the stability of wire feeding and welding processes is guaranteed; the VRD control circuit is adopted, so that the welding machine has a VRD function under manual welding (MMA), namely argon arc welding (TIG) and MIG/MAG gas shielded welding, and the VRD function is also realized, and the use safety of the welding machine is further improved. Therefore, the technical performance and reliability of the product are improved by using a plurality of technical methods.
The circuit principle, the circuit board and the whole machine structure of the welding machine are designed with own unique features. The utility model is protected by the protection of the circuit and the structural design of the welding machine.
Drawings
FIG. 1 is a schematic structural view of an exemplary welder made using the present invention;
FIG. 2 is a schematic block circuit diagram of the welder of the present invention;
FIG. 3 is a schematic circuit diagram of the main circuit and power circuit board portions of the welder of the present invention;
FIG. 4 is a schematic circuit diagram of the input EMI filter circuit board portion of the welder of the present invention;
FIG. 5 is a schematic circuit diagram of the display and operation control panel portion of the LCD screen of the welder of the present invention;
FIG. 6 is a schematic circuit diagram of the small control board portion of the welder of the present invention;
FIG. 7 is a first schematic circuit diagram of the main control board portion of the welder of the present invention;
FIG. 8 is a second electrical schematic diagram of the main control board portion of the welder of the present invention.
Detailed Description
As shown in fig. 1. FIG. 1 is a schematic structural design diagram of a multifunctional welder for single-phase multi-voltage LCD single-encoder parameter adjustment made by the present invention. The welding machine includes:
1) a wire feeding portion comprising: the welding wire reel shaft 5, the wire feeding mechanism 10, the European style gas shielded welding torch interfaces 8 and 9 and the wire feeding control circuit part on the main control circuit board thereof are used in gas shielded welding. The wire feeding mechanism 10 adopts the support frame 11 of the wire feeding mechanism, the plastic backing plate 12 of the wire feeding mechanism, the fixed support I13 of the wire feeding mechanism and the fixed support II 14 of the wire feeding mechanism to carry out insulation isolation and fixed installation with the vertical middle partition 15 and the bottom plate 27. The wire feed reel shaft 5 is mounted on an internal vertical center partition 15. The wire feeder 10 is adjacent to the welder front panel 30. The wire feeder 10 is connected with the welding gun interface 9 of the European gas shielded welding installed on the front panel 30. During gas shield welding, a gas shield welding gun is connected with the European gas shield welding gun interface 9 in a matching way. (1 or 5Kg) welding wire is mounted on the wire drum shaft 5. After being installed, the welding wire can be sent to a wire feeding mechanism 10 and then is conveyed to the head of a welding gun connected with the welding wire through a welding gun interface 9 of European gas shielded welding. The wire can be extended from the contact tip of the gas shielded welding torch by the wire feeding wheel and the pinch wheel of the wire feeder 10 under the control of the circuit. During gas shielded welding, the wire feeding speed of the welding wire is controlled by the circuit board and the corresponding wire feeding speed parameter. The welding current can be changed by adjusting the wire feeding speed. The shielding gas port of the welding gun port 9 for European gas shielded welding is connected to the electromagnetic gas valve 20 through a gas pipe. Shielding gas is coupled from the exterior of the welder to the gas input port of the solenoid gas valve 20. After the gas cylinder is opened, the electromagnetic gas valve 20 can be switched on and off under the control of a welding machine circuit through operation control, so that protective gas is connected into a welding gun and flows out of the head of the welding gun, and metal protection of a welding area is realized. During manual welding and argon arc welding, the wire feeding part is not controlled.
2) A housing portion. Comprises a handle 2, a shell 2, a door catch 3, a side cover plate 4, a bottom plate 29, a front plastic panel 30 and a rear plastic panel 24.
3) The components mounted on the rear plastic panel 24 are: a power switch 22, an input voltage switch 21, a power supply power line and a plug 18 thereof, a pull-off 17 (also called a wire fixing device) of the power line, a rear panel cooling fan 26 and a fixing bracket 25 thereof, an air connector or an air inlet nozzle of protective air and an electromagnetic air valve 20. The cooling fan mounting bracket may be screwed to the bottom plate 29 of the housing and the cooling fan 26 may be screwed thereto. The power supply cord and its plug 18 are connected to the power grid and switched using an input power switching outlet as necessary. The power switch 20 controls the on or off of the welder's power supply. The cooling fan 26 performs forced air cooling of some parts inside the butt welder. The cooling fan 26 is located at the rear of the welder and the cold air is supplied from the air inlet at the rear of the rear panel of the welder chassis. Some heating devices or parts on the upper part of the internal circuit board, such as an IGBT (insulated gate bipolar transistor), a radiator, a fast recovery diode, a radiator and the like can be well cooled. According to different requirements of welding output current and load duration rate, a cooling fan can be arranged on an inverter main circuit and a power circuit board in the welding machine. The design of the air duct and the cooling mode is beneficial to ensuring the working reliability of the welding machine circuit, and is one of the important reasons for realizing larger current and high load duration rate of the welding machine.
4) The parts mounted on the front plastic panel 30 include: the welding gun comprises a fixed seat 8 of the European-style welding gun interface, the European-style welding gun interface 9, a black negative polarity output quick connector seat assembly 31, a red positive polarity output quick connector seat assembly 32, a welding gun polarity conversion plug and a welding cable 34 connected with the welding gun polarity conversion plug, a wire-drawing SPOOL welding gun connecting wire socket 33, a liquid crystal display and operation control panel 36, a front panel metal platelet 35 and a protection box 7 of a front control panel.
5) In the interior of the welding machine, except for parts installed on the front panel and the rear panel, the vertical middle partition plate 15 is fixed on the bottom plate 29 through screws; the EMI filtering plate can be selectively used according to a manufacturing welding machine and is arranged on the vertical middle partition plate 15 through screws; the main control board 16 is also mounted on the vertical middle partition board 15 through screws; the main circuit plus power supply circuit board 28 comprises a small control board arranged on the circuit board, the small control board is used as an assembly and is fixed on a bottom plate 29 through a support piece and screws, one side of the assembly is arranged facing the vertical middle partition plate 15, a protective polyester film 27 is fixed on the welding surface of the circuit board 28, and the protective polyester film 27 is used for protecting the circuit board; the main circuit + power circuit board 28 also has fast recovery diodes 37 and their aluminum heat sinks, IGBT tube banks 39 and 40 and their aluminum heat sinks, circuit board cooling fan 39, inverter main transformer, and a large number of electronic components and parts.
In addition, in terms of structural design, as shown in fig. 1, the left mechanical part of the interior of the welding machine is separated from the right circuit board part by a vertical middle partition plate. The right control circuit part is surrounded by a shell composed of a vertical middle partition plate, a shell, a bottom plate, a rear panel and a front panel. The welding machine can play a role in isolating large-current strong electromagnetic interference, limiting electromagnetic radiation and improving the reliability of the welding machine.
The welding machine of the utility model has two groups of output quick connector seat assemblies which are respectively used for connecting a welding clamp cable and a workpiece clamp cable during manual electric arc welding. The polarity of the connection can be determined according to the type and requirements of the welding electrode. Red, representing a positive output; black, representing negative output; during argon arc welding, the argon arc welding gun is connected to the negative polarity output quick connector seat assembly, and the positive polarity output quick connector seat assembly is connected to the workpiece to be welded. The gas pipe of the welding gun is connected to a gas supply system through a gas pipe connected to the outside; and the welding gun is connected to the European welding gun interface component during gas shielded welding. Black output quick connector mount assemblies are commonly used to connect to a workholder weld cable in a manner known as a reverse or reverse polarity connection. The polarity conversion plug is respectively connected to the positive and negative polarity ends of the output of the welding machine, so that the polarity connection mode conversion of the welding output can be realized. Whether reverse or reverse polarity or positive polarity is used depends on the type of gas shielded welding wire and the requirements of the welding process.
For the Circuit board part of the Control board, the Circuit board is designed into five Circuit boards, namely an EMI input filter Circuit board (EMI), a Main Circuit and Power supply (Main Circuit + Power-PCB) Circuit board, a display and Operation Control Circuit board (Operation + Dispaly-PCB), a solenoid valve Control and current feedback signal amplification, conversion processing Control board or Small Control board (Small-PCB) (note that the Small Control board (Small-PCB) is arranged on the Main Circuit and the Power supply Circuit board), and a Main Control Circuit board (Main Control-PCB), wherein the EMI input filter Circuit board (EMI) can be selected and matched according to the requirements of EMC electromagnetic compatibility test and authentication.
Referring to FIG. 2, the single-phase input power supply 110-120V or 220-240V of the welding machine is connected to the L, N terminal. The PE end is connected with the protective grounding of the power supply system, and meanwhile, the PE end is also connected with a metal rack or a shell of the welding machine; a power switch S1 is arranged on the rear panel of the welding machine; for the welder with multiple input power supply voltages, a rear panel of the welder is also provided with a power supply voltage selection change-over switch, for example, the welder with 120V/220V power supply voltage is provided with a 120V/220V power supply voltage selection switch, and a user needs to correspondingly select the power supply voltage according to the type of the power supply input voltage; at the rear stage of a power switch of the welding machine, and at the same time, in the welding machine close to the power supply input, a manufacturer of the welding machine can selectively match an EMI input filter circuit board (EMI) for installation according to the requirements of EMC electromagnetic compatibility test and certification; if not, the EMI filter circuit board is not installed; then, the Power supply is connected to the Main Circuit and the Power supply (Main Circuit + Power-PCB) Circuit board, the OUTPUT positive polarity OUTPUT (+), and the negative polarity OUTPUT (-) of the Circuit board are respectively connected to the terminals of the OUTPUT positive polarity and negative polarity quick connector components installed on the front panel of the welding machine, meanwhile, the welding current conducting terminal of the MIG/MAG gas shielded welding European connector component installed on the front panel of the welding machine is connected with the polarity conversion quick plug installed on the front panel of the welding machine through the welding cable inside the welding machine, and can be respectively connected with the sockets of the OUTPUT positive polarity and negative polarity quick connector components installed on the front panel through the polarity conversion quick plug, so as to realize the conversion purpose that the conducting nozzle of the MIG/MAG gas shielded welding gun can be connected with both the OUTPUT positive polarity and the OUTPUT negative polarity, and certainly, before welding, if the MIG/MAG gas shielded welding gun outputs positive polarity, the workpiece is connected with and outputs negative polarity; if the MIG/MAG gas shield welding gun outputs a negative polarity, then the workpiece is connected to output a positive polarity. Therefore, the use requirements of different welding wire polarity selections can be met. If the welding is argon arc welding (TIG) or manual welding (MMA), the polarity conversion quick plug is not connected with the output positive and negative polarity sockets outside the welding machine, but is connected with an argon arc welding (TIG) welding gun or a manual welding (MMA) electrode holder and a workpiece according to the connection mode requirements of the two welding methods. In the cooling Fan in fig. 2, two socket interfaces, CN5 and CN15, are disposed on the Circuit board of the Main Circuit and the Power supply (Main Circuit + Power-PCB), respectively, and can be used to connect the cooling Fan; the number of the cooling fans Fan can be selected according to the rated current of the welding machine, for example, for a 200A machine type, in order to ensure that the welding machine has a sufficient load duration rate, two cooling fans Fan are required to be arranged, wherein one cooling Fan is installed on the rear panel of the welding machine, and the other cooling Fan is installed on a Main Circuit and a Power supply (Main Circuit + Power-PCB) Circuit board; for the model 170A or 140A, only one cooling Fan can be configured and installed on the rear panel of the welding machine, and of course, if two cooling fans Fan are still selected, the actual load duration rate of the welding machine can reach a high value; the design of double cooling fans can be selected and matched, which is beneficial to flexible matching of performance parameters when the welding machine is manufactured; the CN4 socket of the Main Circuit and Power supply (Main Circuit + Power-PCB) Circuit board is connected with the CN1 socket of the electromagnetic valve control and current feedback signal amplification and conversion processing control board or Small control board (Small-PCB) through a plug and a connecting wire thereof, and the GAS socket of the latter is connected with the electromagnetic valve in the welding machine through the plug and the connecting wire thereof; small control boards (Small-PCB) are arranged on the main circuit and the power circuit board; CN1, CN3, CN6 and CN16 sockets of a Main Circuit and a Power supply (Main Circuit + Power-PCB) Circuit board are respectively connected with CN1, CN7, CN2 and CN9 sockets of a Main Control Circuit board (Main Control-PCB) through plugs and connecting wires thereof; the CN4 socket of the Main Control circuit board (Main Control-PCB) is connected with the CN1 socket of the display and Operation Control circuit board (Operation + Dispaly-PCB) through a plug and a connecting wire thereof; the MOTO socket of a Main Control circuit board (Main Control-PCB) is connected with a Control line of a Wire feeder motor (Wire feeder) through a plug and a connecting Wire thereof; a GUN Switch socket of a Main Control circuit board (Main Control-PCB) is connected with a welding GUN Switch Control line of a European type welding GUN interface on a front panel of the welding machine through a plug and a connecting line thereof; an OH socket of a Main Control circuit board (Main Control-PCB) is connected with a connecting wire of an overheating protection temperature controller WKQ through a plug and a connecting wire thereof, and the overheating protection temperature controller WKQ is installed by clinging to the surface of a radiator of the IGBT; if a user does not use the European interface to connect the welding gun but uses the SPOOL wiredrawing MIG/MAG gas shield welding gun to weld, the plug of the SPOOL wiredrawing welding gun can be connected with the socket of the wiredrawing welding gun arranged above and below the front panel of the welding machine; meanwhile, a user needs to switch the MIG/SPOOL welding gun on the vertical middle partition plate in the drawing 1 to be connected with the change-over switch, namely the switch is shifted to one side of the corresponding wire drawing gun; the MIG/SPOOL socket of a Main Control circuit board (Main Control-PCB) is connected with a MIG/SPOOL welding gun access transfer switch on a vertical middle partition board in a welding machine attached figure 1 through a plug and a connecting wire thereof; the switching-in of the MIG/SPOOL welding gun to the switch not only has a switching control signal line for U2 in fig. 7, but also has a control line for switching the armature of the wire feeder, namely the latter can realize the switching of the armature connection mode of the wire feeder of two welding guns; if the European style welding gun is used, the change-over switch is arranged on one side of the European style welding gun, and the change-over switch is simultaneously communicated with the armature control end of the wire feeder 10 in the figure 1; if the wire drawing gun is used, the armature control wire can be communicated to the armature control wire of the wire drawing gun corresponding to the socket below the front panel of the welding machine; the Control lines of the wire-drawing MIG/MAG gas shielded welding gun socket on the front panel are respectively connected to the motor armature voltage output line on the Main Control board (Main Control-PCB) and two ends of the Control line of the welding gun switch, and the switch of the wire-drawing gun is adopted for welding Control operation during welding; the SPOOL wire drawing type welding gun is mainly used for welding thin welding wires and aluminum welding wires, and is not easy to generate abnormal welding problems such as wire blocking or unstable wire feeding. The 120V/240V socket of the Main Control circuit board (Main Control-PCB) is connected with the 110-through 120V and 220-through 240V power supply change-over switches on the rear panel of the welding machine through the plug and the connecting wire thereof, and correspondingly inputs the voltage grade signal to the Main Control board circuit through the change-over of the switches.
Fig. 2 to 7 together form a complete control circuit schematic diagram of the welding machine. And connecting control lines and parts are additionally arranged between each control circuit board and external parts thereof and are connected together according to a circuit schematic diagram. Finally, under the action of the control circuit, various control requirements, operation and state display functions of manual electric arc welding (MMA), argon arc welding (TIG) and MIG/MAG gas shielded welding are respectively realized.
The working principle of the welding machine circuit of the utility model is briefly described as follows:
the circuit of the welding machine part shown in figure 3 comprises an inverter main circuit, a high-voltage side driving circuit of an IGBT (insulated gate bipolar transistor), and a switching power supply circuit, wherein the main circuit comprises an input EMI (electro-magnetic interference) filter circuit (note: if the EMI filter circuit board is used, the input EMI filter circuit is provided), an upper electricity buffer circuit, a voltage doubling conversion circuit and a control circuit thereof, a half-bridge inverter circuit, a direct current bus current detection and signal conversion processing circuit in a primary circuit of an inverter transformer, an output filter and overvoltage protection circuit, a VRD output control circuit, an absorption protection circuit of the IGBT, and an absorption protection circuit of a fast recovery diode.
1) The inverter main circuit is shown in fig. 1 and 3. The main inverter circuit of the welding machine mainly comprises a power switch S1, an input EMI filter circuit (note: if an EMI filter circuit board is used, the circuit is provided), an upper electricity buffer circuit, a rectifier B1, a voltage doubling control and conversion circuit, filter electrolytic capacitors C3-C6, converter capacitors C1-C9 and C2-C8, a filter capacitor C7, six IGBT tubes Q1, Q2, Q13 (as a group of switches) and Q3, Q4 and Q14 (as another group of switches), an inverter main transformer T1, a main transformer primary current detection mutual inductor HGQ, four double fast recovery diodes (such as SL60F30 and the like) D1-D3 and D5, shunts FLQ1 and FLQ2 for output current detection, an output filter and overvoltage protection circuit, a VRD output control circuit, an output voltage detection signal output plug CN16, an absorption protection circuit of the IGBT and an absorption protection circuit of the fast recovery diodes.
Referring to FIG. 3, a single-phase 110-120V or 220-240V input power voltage is connected to the power switch S1. The mains power is switched on by means of a power switch S1 on the rear panel of the welder.
2) Input EMI filter circuit, referring to fig. 3, ac power from the grid is first passed through an input EMI filter circuit (note: if an EMI filter Circuit board is used, the Circuit is present and functions accordingly), and then to the Main Circuit and Power supply (Main Circuit + Power-PCB) portion of the subsequent stage. The circuit has the main effects of reducing the interference of a power grid power supply to the inverter welding machine circuit, improving the working reliability of the welding machine, simultaneously reducing the interference of interference signals generated by the inverter circuit to the power grid, and playing a role in good EMC electromagnetic compatibility.
For the circuit of an EMI input filter circuit board (EMI), the circuit schematic diagram of the part is shown in FIG. 4, and the circuit consists of 1MT1, 1MT2 common mode inductor, 1R1 resistor and 1C 1-1C 5 capacitor; the 1C1 capacitor is connected in parallel at two ends of the input stage of the EMI filter, the rear stage of the EMI filter is connected with a 1MT1 common mode inductor, the rear stage of the 1MT1 common mode inductor is connected with a 1R1 resistor and a 1C2 capacitor in parallel, one end of the 1MT1 common mode inductor is connected with a 1C3 capacitor, the other end of the 1MT1 common mode inductor is connected with a 1C4 capacitor, and the other ends of the 1C3 capacitor and the 1C4 capacitor are connected with a protective grounding end of a PE end (welding machine frame); the rear stage of the 1MT1 common mode inductor is connected with a 1MT2 common mode inductor, and the rear stage of the 1MT2 common mode inductor is connected with a 1C5 capacitor in parallel; 1C1, 1MT1 and 1C2 form a first-stage double pi-shaped filter network, 1C2, 1MT2 and 1C5 form a second-stage double pi-shaped filter network, and the networks mainly suppress electromagnetic noise and clutter signals of an input power supply, prevent interference on a welding power supply control circuit and prevent interference of high-frequency clutter generated by the welding power supply on a power grid; 1C3 and 1C4 are safety capacitors; the arrangement of the input filter circuit is one of important preconditions for ensuring that the welding machine can pass EMC electromagnetic compatibility authentication, and is also one of important measures for resisting interference of a hardware circuit and improving the reliability of the welding machine. The circuit of the EMI input filter circuit board is connected with the rear stage of a power switch of the welding machine and is arranged in the welding machine close to the power supply input, and a manufacturer of the welding machine can select and match the EMI input filter circuit board for installation according to the requirements of EMC electromagnetic compatibility test and authentication; if not, the EMI filter circuit board is not installed.
3) Referring to fig. 3, the input ac power also passes through the power-on buffer circuit composed of the PTC1 thermistor and the contact terminal RLY1-1 of the relay RLY1, and then is rectified by the rectifier B1 to become pulsating dc power, and the electrolytic capacitors C3 to C6 are charged, and the voltage gradually rises and finally becomes more stable high-voltage dc power. For the power-on buffer circuit, the power-on buffer circuit consists of a contact RLY1-1 of a relay RLY1 and a PTC1 thermistor; the control circuit of the relay RLY1 is composed of a field effect transistor Q5(IRFZ24N), a diode D4, a voltage regulator tube Z1, resistors R10 and R11, an electrolytic capacitor C16 and a +24V power supply; the contact RLY1-1 of the RLY1 relay is connected with the PTC1 thermistor in parallel, and is connected between the power supply of the welding machine and the input end of the rectifier bridge B1 in series; the action time of the RLY1 relay lags behind the closing time of the power switch S1, namely the RLY1 relay is operated in a delayed mode. When the charging voltage of the electrolytic capacitors C3-C6 is stabilized, the RLY1 relay operates, the contact RLY1-1 closes the PTC1 thermistor, and when the welding machine works in a normal inversion mode, large current flows from RLY1-1 of the RLY1 relay. Such a circuit is called a power-on buffer circuit. The power switch S1 is mainly prevented from being burnt out due to the fact that no voltage exists between the electrolytic capacitors C3-C6 at the moment of switching on the power switch, which is equivalent to short circuit. The function of the power-on buffer circuit is to limit surge current by connecting a PTC1 thermistor in series at the moment of switching on. The resistance of the PTC1 thermistor increases as the temperature thereof increases. Therefore, the power-on buffer circuit can play a better protection role. The power-on buffer part circuit is realized by the following control mode: in FIG. 3, the +24V voltage is developed later than the time when the welder power switch S1 is closed. The voltage across capacitor C16 increases in steps after the +24V voltage is added. Because, R10 and C16 constitute an integrating circuit. When the voltage on the capacitor C16 rises to a certain value, the MOS transistor Q5 can be turned on. Thus, the RLY1 relay will act.
4) The utility model relates to a voltage-multiplying control and conversion circuit, in particular to an inverter welding machine with multiple input power supply voltages of 110-120V and 220-240V, the utility model also designs the voltage-multiplying control and conversion circuit, which is shown in figure 3 and consists of a relay RLY2 coil and a contact RLY2-1 thereof, and a PNP type triode Q11, an NPN type triode Q12, a diode D38, resistors R106-R110, a capacitor C68, a voltage-multiplying control signal BEIYA control end, +15V, +24V power supply; the Control end of the voltage doubling Control signal BEIYA is connected to the 8 pin of the CN1 plug, and is connected to the CN1 plug of the Main Control board (Main Control-PCB) through the plug and the Control line thereof, and actually is a Control signal of the U2(MC96F8316D) microprocessing Control circuit 03 controlled by the Main Control board (Main Control-PCB), as shown in fig. 7; the relay RLY2 is 40A/24V, D38 is connected in parallel at two ends of a coil of the relay RLY2, and the cathode of D38 is connected with + 24V; one end of a contact RLY2-1 is connected with an input end of an input power supply and rectifier bridge B1, the input end is not the input end of the upper electric buffer circuit connected with B1, and the other end of a relay contact RLY2-1 is connected with the middle connection point of electrolytic capacitors C3-C4 and resistors R120, C5-C6 which are connected in parallel in a filter circuit after rectification of B1 and a resistor R122; the rectifier bridge B1, electrolytic capacitors C3-C4 and C5-C6 which are connected in parallel at the output end of the B1, and the connection mode of a relay contact RLY2-1 with the electrolytic capacitors and the B1 jointly form a voltage-multiplying conversion circuit, and the control ends of other components, such as Q11, Q12, resistors R106-R110, a capacitor C68 and a voltage-multiplying control signal BEIYA, form a control circuit of the voltage-multiplying conversion circuit; for the multi-input power supply voltage, the voltage doubling conversion and the control circuit thereof work when low voltage is input, but do not work when high voltage is input; for example, when a 220-240V power supply supplies power, the voltage doubling control signal BEIYA cannot enable the Q12 triode to be conducted, the relay RLY2 cannot act, the contact RLY2-1 is not closed, at the moment, a B1 rectifier bridge and a filter circuit of the rear stages C3-C4 and C5-C6 do not have voltage doubling, the circuit is a full-wave rectifier circuit, and the rectified voltage is added to two ends of two groups of series capacitors of C3-C4 and C5-C6; the output voltage of the power supply is + VCC voltage, which is +310V when 220V power supply is input, and is higher when 230V or 240V power supply is input; when the 110V-120V power supply supplies power, if voltage doubling is not carried out, the obtained + VCC voltage is very low, which is very unfavorable for the inverter main circuit of the welding machine to output larger current and voltage, therefore, voltage doubling conversion is required; the welder of the utility model utilizes the U2(MC96F8316D) of the Main Control board (Main Control-PCB) to micro-process the output of the Control signal of the Control circuit 03 to obtain a voltage doubling Control signal BEIYA, the Q12 triode can be conducted through the voltage doubling Control signal BEIYA, the relay RLY2 acts, the contact RLY2-1 is closed, at this time, the B1 rectifier bridge and the circuit of the rear stage and the resistors R120 and R122, the electrolytic capacitors C3-C4 and C5-C6 are respectively charged for each half cycle of the alternating current input because the closed contact RLY2-1 is connected between the input end of the B1 and the middle connection points of the resistors R120 and R122, the electrolytic capacitors C3-C4 and the electrolytic capacitors C5-C6, the finally output voltage is the voltage of the two groups of electrolytic capacitors C3-C4 and C5-C6 which are connected in series, therefore, the VCC conversion function is output, when the voltage is still about 110V +310, the input level is still about 310, the welding machine can output larger welding current and voltage under low power supply voltage conveniently;
5) referring to fig. 3, the half-bridge inverter circuit is composed of commutation capacitors C1-C9 and C2-C8, a filter capacitor C7, six IGBT transistors Q1, Q2, Q13 (which are a set of switches), Q3, Q4 and Q14 (which are another set of switches), an inverter main transformer T1, a main primary current detection transformer HGQ, four double-fast recovery diodes (such as SL60F 30) D1-D3 and D5, shunts FLQ1 and FLQ2 for output current detection, and the like. The + VCC high voltage DC obtained after the input power is rectified by rectifier B1 and filtered by the electrolytic capacitor is supplied to the half-bridge inverter circuit on the one hand, and on the other hand, referring to fig. 3, the + VCC high voltage DC bus voltage (also the voltage at both ends DC +, DC-) is supplied to the switching power supply circuit (the lower left circuit part in fig. 3) through the connection line. The half-bridge inverter circuit mainly has the following functions: the high voltage direct current bus voltage is converted into medium frequency (dozens of KHz) alternating current. The inversion main transformer T1 realizes voltage reduction and conversion of large current output. Fast recovery diodes (such as SL60F 30) D1-D3 and D5 convert the medium frequency AC output by the inverter transformer into DC. The output current is detected by the current dividers FLQ1, FLQ2, the detection signal FL +, FL-is transmitted to the CN1 plug on the Small Control panel (Small-PCB) through the CN4 plug on the Main Circuit and the Power panel (Main Circuit + Power-PCB), and is converted into IFB or ADCI2 by the current signal amplifying and processing Circuit on the Small Control panel (Small-PCB), and finally, the relevant Control Circuit returned to the Main Control panel (Main Control-PCB) by the CN4 plug is used as a current negative feedback signal and a display signal to participate in the Control and display Control of the welding machine.
6) An absorption protection circuit of the IGBT, see fig. 3, in the half-bridge inverter circuit, C7 is a filter capacitor; the series-connected R1 and C6 are connected in parallel at D, S ends of Q1, Q2 and Q13 IGBT tubes to form a resistance-capacitance absorption circuit to protect the IGBT; similarly, the series connection of R4 and C11 is connected in parallel at D, S ends of Q3, Q4 and Q14 IGBT tubes, and a resistance-capacitance absorption circuit is also formed.
7) An output filtering and overvoltage protection circuit, as shown in fig. 3, is provided with an output filtering and anti-interference circuit consisting of a piezoresistor RV1, a capacitor CY1 and a capacitor CY2 in an output loop of the welding machine; RV1 is connected in parallel to two ends of positive polarity OUTPUT (+) and negative polarity OUTPUT (-) of OUTPUT of the welding machine for preventing overvoltage; one end of CY1 is connected to the positive OUTPUT (+) end of the OUTPUT, and the other end of CY1 is connected to the protective grounding ends of the rack and the power supply system; one end of CY2 is connected to the OUTPUT negative polarity OUTPUT (-) end, and the other end of CY2 is connected to the protective grounding ends of the rack and the power supply system; the capacitors CY1 and CY2 are used for preventing the high-frequency interference signals entering the output end from having adverse effects on the control circuit;
8) a VRD OUTPUT control circuit, see FIG. 3, in the OUTPUT loop of the welder, a VRD OUTPUT control circuit is arranged, the circuit consists of a +15V power supply, a D37 diode, R102 and R103 and a R5 resistor, the anode of D37 is connected with +15V, the cathode of D37 is connected with R102, the other end of R102 is connected with an OUTPUT positive polarity OUTPUT (+) terminal, R5 is connected in parallel with the two ends of the OUTPUT positive polarity OUTPUT (+) and negative polarity OUTPUT (-) of the welder, R103 is connected with an OUTPUT negative polarity OUTPUT (-) terminal, and the other end of R103 is grounded; when the power supply switch of the welder is closed, the +15V power supply can be generated by the switch power supply circuit, so that the two ends of R5, namely the two ends of the positive polarity OUTPUT (+) and the negative polarity OUTPUT (-) of the OUTPUT of the welder have the direct current no-load voltage of about 13V through the VRD OUTPUT control circuit, thereby realizing the no-load low-voltage OUTPUT of the welder. The utility model has VRD function under three different welding methods. Once the welder is switched into the welding arc load operating state for different welding methods, the OUTPUT voltage, current, across the positive polarity OUTPUT (+) and negative polarity OUTPUT (-) of the welder will depend on the OUTPUT current or voltage setting of the welder and the magnitude of the arc load.
In the OUTPUT loop of the welding machine, an OUTPUT voltage sampling part is also arranged, a pin 1 of CN16 is connected with a positive polarity OUTPUT (+) terminal of the welding machine, a pin 2 of CN16 is connected with a negative polarity OUTPUT (-) terminal of the welding machine, and voltage sampling signals are OUTPUT from two ends of a CN16 socket and are input to a CN9 socket of a Main Control board (Main Control-PCB) through a plug and a Control line thereof.
9) The absorption protection circuit of the fast recovery diode is shown in fig. 3 and comprises resistors R8 and R112 which are connected in parallel, resistors R16 and R111, and capacitors C10 and C17, wherein the resistor C10 is connected in series with the resistors R8 and R112 which are connected in parallel and then connected in parallel at two ends of the fast recovery diodes D1 and D2; similarly, the C17 is connected in series with the parallel resistors R16 and R111 and then connected in parallel to the two ends of the D3 and D5 fast recovery diodes. The resistor-capacitor series protection circuit is also an absorption circuit of the diode, and can prevent the diode from being damaged by peak overvoltage.
10) A switching power supply circuit (lower left circuit part in fig. 3), see fig. 3, supplied with + VCC high voltage DC bus voltage (also voltage across DC +, DC-) via a connection line; the switching power supply circuit consists of a T switching power supply transformer, an optocoupler U (EL817), a switching power supply control chip U (TOP 246), D and D diodes, D-D, D and D fast diodes, a programmable transistor Q (TL431), an integrated voltage stabilizer U (LM7815), U (LM7805), a filter inductor L, and resistors R, R-R, R104, R105, R123, capacitors CY, C and C around the T switching power supply transformer, the optocoupler U (EL817), the switching power supply control chip U (TOP 246), the D and D diodes, the programmable transistor Q (TL431), the integrated voltage stabilizer U (LM7805), the filter inductor L, and the resistors R, R-R, R105, R123, the capacitors CY, C and C; generating +5V, +15V, +24V2, -15V power supply voltage, and supplying the power supply voltage to other corresponding control circuits for live working; the T2 switch power supply transformer has 5 windings, N1-N5, N1 and N2 are high-voltage side windings, and N3-N5 are low-voltage side windings.
The switch power supply circuit is electrically isolated by a U10 optocoupler and a T2 switch power supply transformer and is divided into a high-voltage side circuit and a low-voltage side circuit:
A) in a high-voltage side circuit of the switching power supply, a pin 3 of N1 is connected with a pin 5 of U7 and an anode of D18, a cathode of D18 is connected with R30, the other ends of R30 are connected with R26 and C26, and the other ends of R26 and C26 are connected with a pin 1 of N1; pins 2, 3, 7 and 8 of U7 are grounded; the 1 pin of U7 is connected with R29 and R32 which are connected in series, and the other end of R32 is connected with the 1 pin of N1; the 1 pin of the CN2 socket is grounded, the 3 pin of the CN2 socket is connected with the anode of D11, the cathode of D11 is connected with the cathode of D10 and the 1 pin of N1, the anode of D10 is connected with the DC + end of + VCC voltage, the 1 pin of the cathode N1 of D10 and the CY3 capacitor; a C25 electrolytic capacitor and a C27 are also connected between the pin 1 of the N1 and the ground in parallel, and the negative electrode of the C25 is grounded; the other end of the capacitor CY3 is connected to the ground of the low-voltage side circuit of the switching power supply transformer T2; c43, R47 and C40 electrolytic capacitors which are connected in series are connected between the 4 pins of U7 and the ground in parallel, the negative electrode of C40 is grounded, meanwhile, the 4 pins of U7 are connected with the emitter of a U10 optical coupler middle output stage triode, the collector of the triode is connected with the cathodes of C33, C34 and D22, the other ends of C33 and C34 are grounded, the anode of D22 is connected with the 5 pin of N2, and the 4 pin of N2 is grounded;
B) for a low-voltage side circuit of the switching power supply, a pin 6 of N3 is connected with an anode of D19, a capacitor C31, a resistor R31, a C32 electrolytic capacitor and a CN3 socket are connected in parallel between a cathode of D19 and a pin 7 (GND2) of N3, an anode of C32 is connected with a cathode of D19, and the CN3, a plug thereof and a Control line are connected with the CN7 socket of a Main Control board (Main Control-PCB), so that a +15V1 power supply is obtained for the next step and is used as an operating voltage for supplying power to a wire feeding Control circuit, and the power supply is shown in figure 7. The middle connection point of N4 and N5 is grounded, the other end of N5 is connected with the anodes of R21, C18 and D14 and D16 which are connected in series, the other end of C18 is connected with the cathodes of D14 and D16, R39, R42, +24V, the other end of R39 is connected with R43, and a C21 capacitor and a C20 electrolytic capacitor are connected in parallel between the +24V power supply and the ground; the other end of the R42 is connected with the anode of a U10 light-emitting diode in the optical coupler, the cathode of the light-emitting diode is connected with the cathode of Q9 and a C39 capacitor, the other end of the C39 is connected with the other ends of R43, R52 and R39 and the reference pole of Q9, and the anode of Q9 and the other end of the R52 are grounded; the secondary output of the switching power supply is fed back to the primary side of the switching power supply through a circuit formed by a U10 optocoupler and peripheral elements thereof; a +24V2 power supply is obtained after the +24V passes through R25, a C33 capacitor and a C34 electrolytic filter capacitor are connected in parallel between the power supply and the ground, the power supply is used as an input power supply of U5(LM7815), a +15V power supply is obtained through the voltage stabilization of U5, and a C24 capacitor and a C23 electrolytic filter capacitor are connected in parallel between the +15V power supply and the ground; the 8 feet of N4 are connected with the anode of D36 and the cathode of D17, the cathode of D36 is connected with an inductor of L1, the other end of L1 is connected with capacitors of C69 and C66 which are connected in series, the other ends of R104 and C66 are grounded, the other end of R104 is an INAC signal end, and C67 and R105 are connected in parallel between the signal end and the ground; a C28 capacitor, a C29 electrolytic capacitor and an R28 are connected between the anode of the D17 and the ground in parallel, and a-15V power supply is obtained at the cathode end of the D17; a C14 capacitor and a C13 electrolytic filter capacitor are connected in parallel between the +24V2 power supply and the ground, and are used as an input power supply of U1(LM7805) to obtain a +5V power supply through the voltage stabilization of U1, and a C19 capacitor, an R123 resistor and a C15 electrolytic filter capacitor are connected in parallel between the +5V power supply and the ground; the-15V, +5V, INAC signal terminals are respectively connected to the 5, 4, 2 and 1 pins of a CN1 socket, and are connected to a CN1 socket of a Main Control board (Main Control-PCB) through a plug of CN1 and a connecting wire thereof, so as to supply power to the circuits of the Main Control board; the +24V, +15V, -15V are respectively connected to pins 10, 6, 5 of the CN4 socket, and are connected to the CN1 socket of a Small Control board (Small Control-PCB) through a plug of CN4 and a connecting wire thereof, so as to supply power to the electromagnetic air valve Control circuit and the output current detection, signal amplification and conversion processing circuit;
the function of the switching power supply control chip U7(TOP246GN) can be queried about relevant usage data or instructions, which are not repeated here. In addition, as can be seen from the circuit schematic diagram of the switching power supply part, the utility model does not adopt a general control transformer and a related voltage conversion circuit to generate the power supply voltages, and the circuit takes the high-voltage direct-current bus voltage + VCC from the main loop. The size, the size and the weight of the switch transformer are far smaller than those of a common control transformer, so that the cost of the welding machine is reduced, and the technical additional value of the welding machine is improved. Moreover, the switching power supply circuit can still have a stable working state and output voltage when the input power supply of 80-270V changes, so that the application range of the power grid voltage is wide, and the welding machine provided by the utility model is ensured to have stronger power grid voltage fluctuation resistance to a great extent.
11) A current detection transformer HGQ is arranged in a primary circuit of a T1 welding transformer in a half-bridge inversion Main circuit, a secondary output of the HGQ is connected with an input end of a bridge rectifier circuit consisting of diodes D20, D21, D24 and D25, an output end of the bridge rectifier circuit is connected with R35 and R36 in parallel between the ground ends and is also connected with R33, the other end of the R33 is an OC1-2 signal end, a filter capacitor C35 is connected between the ground ends and is connected with the signal end of OC1-2 in parallel between the ground ends, the signal end of the OC1-2 is a T1 primary or direct current bus current detection output signal of the inversion Main circuit, the current detection output signal is connected to a pin 7 of a CN1 socket, and is connected to a CN1 socket of a Main Control-PCB (Main Control-PCB) through a plug of CN1 and a connecting line thereof, and the T1 primary or direct current detection output signal is provided for a circuit of the Main Control board.
12) A driving Circuit of the IGBT, see fig. 3 and 7, the driving Circuit of the IGBT is composed of a T3 driving transformer, a U13 integrated PWM chip (SG3525A), a U14 and U15 driving chip (MSN4688), voltage regulators ZD 7-ZD 10, diodes D30-D31 and D34, transient suppression diodes TVS1, TVS2 and TVS5(SMBJ18CA), resistors R149-R158, resistors R60, R65, R72-R74, R78, R80, R84, R88, R89, R96, capacitors C82-C88 and capacitors C50, C55, +15V and +15V3 Power supplies, sockets CN2 (on Main Control board Main Control-PCB) and CN6 (on Main Circuit and Power supply board + Power-PCB); the CN2 on a socket Main Control board (Main Control-PCB) and the CN6 socket on a Main Circuit and a Power supply board (Main Circuit + Power-PCB) can be connected through a plug and a Control line thereof; the +15V power supply is subjected to voltage reduction by R149 to obtain a +15V3 power supply, and a C83 filter electrolytic capacitor and a C82 anti-jamming capacitor are connected between the +15V3 power supply and the ground in parallel; the drive circuit of the IGBT is divided into a high-voltage side drive circuit and a low-voltage side drive circuit:
A) the Main part of the low-side driving circuit is designed on a Main Control board (Main Control-PCB), see fig. 7. The low-voltage side driving circuit consists of a primary side of a T3 driving transformer, a U14 and U15 driving chip, voltage-stabilizing tubes ZD 7-ZD 10, diodes D30 and D32, resistors R149-R158, capacitors C82-C88 and a +15V power supply.
[ B) the Main part of the high-voltage side driving Circuit is designed on the Main Circuit and the Power board (Main Circuit + Power-PCB), see FIG. 3. The high-voltage side driving circuit is composed of a secondary side of a T3 driving transformer, diodes D31 and D34, transient suppression diodes TVS1, TVS2 and TVS5(SMBJ18CA), resistors R60, R65, R72-R74, R78, R80, R84, R88, R89 and R96, and capacitors C50 and C55.
In a half-bridge inverter main circuit, six IGBT tubes Q1, Q2, Q13, Q3, Q4 and Q14 are divided into two groups of electronic switches, so that two groups of IGBT driving circuits are needed, and the circuit forms of two driving parts are basically consistent; because the PWM signal output by the 11 pin and the 14 pin of the U13 chip has low driving power, the power needs to be amplified by a low-voltage side driving control circuit, the isolation transformer is driven to be isolated by the T3, and finally the on-off working state of two groups of IGBT tubes is controlled by a high-voltage side driving circuit.
In fig. 7, the output control signals of the pins 11 and 14 of the U13 chip are two sets of PWM square-wave pulse signals. The frequency of the square wave is fixed and is tens of KHz. It is determined by the resistance and capacitance parameters (e.g., R132 and C79) of the 6, 5 pin connections of the chip. The two groups of square-wave pulse signals have a fixed time difference in time, which is also known in the art as dead time. The method is one of important parameters for ensuring the alternative work of two groups of switches of the IGBT. This time is determined by the peripheral (e.g., R132 and C79) parameter settings of the U13 chip. How to determine, it can be understood by looking at the relevant use data or description of the U13 chip, and the description is not repeated here. Here, it should be noted that: the PWM signal output by the U13 chip is a signal for determining the output voltage and current of the main inverter circuit of the welding machine. Its pulse width depends on: 1) the manual welding (MMA) control state is determined by the welding current or thrust current given signal and the output current feedback signal. The object or target of control is the output current magnitude. During welding, in the circuit parts of U16B and U16D operational amplifiers (hereinafter referred to as operational amplifiers) in FIG. 8, the control circuit of the U13 part generates corresponding PWM pulse signals through current negative feedback PI (proportion + integration) control, so that two groups of IGBTs are in an alternate conduction state, and finally the inverter main circuit outputs current and voltage. When the operator sets the welding parameters and performs the weld, the control circuit senses the output current signal through shunts FLQ1 and FLQ2 in fig. 3 and obtains either the IFB or ADCI2 signal via signal processing and transformation circuitry. On one hand, the output current signal displayed by the welding machine is obtained, and the current digital display is realized under the action of the liquid crystal display and the operation control circuit. On the other hand, the detected current signal is subjected to analog-to-digital conversion and digital-to-analog conversion under the action of other control circuits (mainly a control circuit of a U2 microprocessor part and an output characteristic control circuit of a U13 part in fig. 7), and is used as a current negative feedback control signal to be compared with a given signal of a welding parameter (such as current or thrust current). The compared difference signals are subjected to PI (proportional plus integral) regulation control in U16B and U16D operational amplifier circuit parts in the graph 8, the output result controls the pulse width or duty ratio of a welding machine output PWM chip, the output current and voltage of the welding machine are determined, and the output current parameters are accurately controlled. And the output characteristic of the welding machine is the descending characteristic of the constant current band out-of-band dragging. Further, when the welding current given signal is unchanged, the current detected by the welding machine circuit increases, and after the given set value is reached, the difference value between the welding current given signal and the current negative feedback control signal decreases along with the increase of the current, and after the PI control, the pulse width or the duty ratio of the welding machine output PWM chip is reduced, and the output voltage of the welding machine is reduced. This process is called current cut-off negative feedback control. I.e. a feedback control which is active only when the current has reached the set value of the welding current potentiometer. Thereafter, as the current increases slightly, the voltage decreases much. When the voltage is reduced to be below 16V, the control circuit can increase the pulse width or the duty ratio of the output PWM chip of the welding machine along with the reduction of the voltage, so that the welding current is increased according to the set parameters of the thrust current, and finally the falling characteristic of constant current out-of-band dragging is formed. The current cutoff negative feedback set point is different when the welding current set signal changes, but the other control processes are similar. In this way, between the minimum and maximum potentiometer settings, numerous droop characteristics can be obtained. Such control is also a basic requirement for satisfying manual arc welding. 2) In the argon arc welding (TIG) control state, the control process is very similar to that of the manual welding. The output characteristic of the welding machine is the constant current descending characteristic only by not carrying out external dragging or thrust current stage control below 16V. 3) And when the gas shield welding control state is carried out, the welding voltage setting signal and the output voltage feedback signal are jointly determined. The object or target of control is the output voltage magnitude. In the U101A operational amplifier circuit part in FIG. 8, voltage negative feedback PI control is adopted. When the welding gun is switched on and off, a larger PWM pulse width signal is output to obtain no-load voltage. After loading, the control is different from that of manual welding. In gas shielded welding, the output characteristic of the welding machine is controlled to be flat rather than the falling characteristic of constant current band out dragging. The method is characterized in that: the load current changes greatly, and the output voltage changes little, and remains relatively stable. Only when the voltage given signal changes does the output voltage change significantly. The above control process is realized by a corresponding control circuit.
Referring to fig. 3 and fig. 7, as mentioned above, a current detection transformer HGQ is disposed in the primary loop of the T1 welding transformer in the half-bridge inverter Main circuit, the secondary output of the HGQ is connected to a bridge rectifier circuit composed of four diodes, the output end of the bridge rectifier circuit is connected to a circuit composed of a resistor and a capacitor, and an OC1-2 primary current detection signal is obtained, which is connected to a CN1 socket of a Main Control board (Main Control-PCB) through a plug and a connecting wire thereof, so as to provide a T1 primary or dc bus current detection output signal OC1-2 to the circuit of the Main Control board, mainly to monitor whether the inverter Main circuit has an overcurrent phenomenon;
an overcurrent protection control circuit and a control process thereof are shown in fig. 7, wherein an OC1-2 signal is connected to a cathode of a ZD6 voltage regulator tube in fig. 7 and an anode of a D29 diode, a cathode of the D29 is connected with R140, C56 and R170, the other ends of R140 and C56 are grounded, the other end of R170 is connected with a base of a rear-stage NPN type triode Q11, a collector of Q11 is connected with R146 and C75 in parallel to ground, a base of Q11 is connected with R145 to ground, Q11 and a peripheral resistor and a capacitor thereof form a switch circuit, an anode of D29 is opposite to a control end of the switch circuit, a collector of Q11 is connected to a pin 8 of a U13 PWM chip in fig. 7, and an emitter of Q11 is grounded; on the other hand, the anode of the voltage regulator tube ZD6 is connected with the control electrode of Q14(SCR thyristor), the cathode of Q14 is connected with the anode of D28, the cathode of D28 is grounded, R139 is connected between the control electrode and the cathode of Q14, the anode of Q14 is connected with the cathode of D23, R138, R125, C57, the other end of R138 is connected with +15V, C57 is connected in parallel with the two ends of R125, the other end of R125 is connected with the base of Q12, the emitter of Q12 is grounded, R124 is connected between the base of Q12 and the ground, the NPN type triode Q12 and its peripheral resistor and capacitor also form a switch circuit, the input end of R125 is opposite to the control end, the collector of Q12 is connected with R111, R110, the other end of R110 is connected with the base of Q11, and the other end of R111 is connected with + 15V; the circuit part formed by the U11A operational amplifier and the peripheral resistor is a voltage comparator, the power supply of U11A is +15V and ground, the non-inverting input end of U11A is connected with the anode of D23, C40, the 1 pin of an OH socket and R88, the other ends of the 2 pin of the socket and C40 are grounded, and the other end of R88 is connected with + 15V; the inverting input end of U11A is connected with R92 and R122, the other end of R92 is connected with +15V, the other end of R122 is grounded, the output end of U11A is connected with R123, R109 and C62, the other end of C62 is grounded, the other end of R109 is connected with IN4, and the sampling end is also a 15-pin signal sampling end of the U2 microprocessor; when the current detection output signal OC1-2 is not large and no overcurrent occurs, Q14 is not conducted, D23 is cut off, U11A outputs high level, at the moment, a 15-pin signal sampling end of an IN4 or U2 microprocessor is high level, an ALARM (ALARM) of a front panel of the welding machine can not be lightened through the output control of the U2 microprocessor, and the welding machine can output current or voltage; on the contrary, when the current detection output signal OC1-2 is too large, namely, when an overcurrent phenomenon occurs, the Q14 is switched on, the D23 is switched on, the Q12 is switched off, the Q11 triode is switched on, and the U13-8 end is pulled down to a low level, so that the U13 chip can close PWM signal output, and finally the welding machine stops outputting current; meanwhile, the U11A outputs low level, the 15-pin signal sampling end of the IN4 or U2 microprocessor is low level, and the ALARM (ALARM) of the front panel of the welding machine can be lightened through the output control of the U2 microprocessor to indicate overcurrent.
An overheat protection control circuit and a control process thereof are shown in fig. 7, in the overcurrent protection control circuit, an OH socket is connected with an overheat protection WKQ temperature controller, and WKQ is closely attached to the surface of an aluminum radiator of an IGBT; when WKQ is not operated and no overcurrent phenomenon occurs, Q14 is not conducted, D23 is cut off, Q12 is conducted, the base level of Q11 is pulled down through R110, Q11 is cut off, and U13-8 is at a higher level; meanwhile, the U11A outputs high level, the 15 pin signal sampling end of the IN4 or U2 microprocessor is high level, and the welding machine can output current or voltage through the output control of the U2 microprocessor and the U13; conversely, when WKQ is active, U11A outputs low level, the 15 pin signal sampling terminal of the IN4 or U2 microprocessor is low level, the 02 signal terminal is high level through the output control of the U2 microprocessor, the 02 signal terminal is connected to R96, the other end of R96 is connected to the base of NPN triode Q8, R114 and C64 are connected IN parallel between the base and ground, the base of Q8 is grounded, the collector of Q8 is connected to the U13-8 signal terminal, since 02 is high level, U13-8 is low level, the U13 chip can turn off PWM signal output, and finally the welder stops outputting current or voltage; meanwhile, because the U11A outputs low level and the 15 pin signal sampling end of the IN4 or U2 microprocessor is low level, the ALARM (ALARM) of the front panel of the welding machine can be lightened through the output control of the U2 microprocessor to indicate overheating. When the temperature is too high, the welding can not be carried out, the cooling fan of the welding machine can continue to work, WKQ can automatically recover after the cooling time, at the moment, the warning (ALARM) of the front panel of the welding machine can be extinguished, and the welding machine can carry out the welding operation again. The overheating protection control process of the welding machine is described above.
The circuit of the control board or the Small control board (Small-PCB) is processed by the control of the electromagnetic valve of the welding machine and the amplification and transformation of a current feedback signal, and is shown in figure 6; small control boards (Small-PCB) are arranged on the main circuit and the power circuit board; the control circuit of the board comprises an electromagnetic air valve control circuit and an amplifying and converting processing circuit for outputting current signals according to functions; the signal for controlling the action of the electromagnetic valve is connected to the GAS control signal end of the main control panel through the CN1 socket on the panel, and is connected with the electromagnetic air valve DCF in the welding machine through the GAS socket on the circuit board by using a plug and a connecting wire thereof; the current feedback signal amplifying and converting processing control Circuit part is characterized in that input signals FL and FL-are connected to corresponding sockets of an inverter Main Circuit and a switching Power supply (Main Circuit + Power-PCB) Circuit board through a CN1 socket on the board by using a plug and a connecting wire thereof, actually two ends of a shunt (FLQ 1 and FLQ2 connected in parallel) in an output Circuit of the welding machine are connected, and current sampling signals are processed by an operational amplifier Circuit and then are transmitted to a Circuit part of a Main control board through an IFB or ADCI2 signal end of a CN1 socket on the board.
On a Small control board (Small PCB), a part of the circuit is a control circuit of an electromagnetic air valve, which is shown in fig. 6 and consists of a PNP type triode Q1, an NPN type triode Q2, a diode D5, resistors R8-R10, a capacitor C6, a GAS plug, a +15V +24V power supply; referring to fig. 2, the DCF is connected to the GAS plug; a CN1 plug is connected with a CN4 plug on a Main Circuit and a Power panel (Main Circuit + Power-PCB), and Power supplies of +24V, +15V and ground are from the CN1 plug; the 1 pin of the GAS plug is connected with +24V, the 2 pin of the GAS plug is connected with the anode of D5 and the collector of a triode Q2, the emitter of Q2 is grounded, the cathode of D5 is connected with +24V, the base of Q2 is connected with R11 and the collector of a triode Q1, the other end of R11 is grounded, the emitter of Q1 is connected with R10, the other end of R10 is connected with +15V, the base of Q1 is connected with R9, the other end of R9 is connected with R8, C6 and a GAS control signal end, the other end of R8 is connected with +15V, and the other end of C6 is grounded; the GAS control signal end is connected to the CN1 plug; the GAS control signal terminal of the CN1 plug is a control signal for controlling the solenoid valve. When the control level of the GAS control signal end is high, the triode Q1 is conducted, so that the triode Q2 is conducted, and the electromagnetic air valve connected to the GAS plug port acts. Otherwise, the electromagnetic air valve is closed. This makes it possible to control the on/off of the shielding gas.
On a Small control board (Small PCB), a part of circuits are circuits for detecting and amplifying output current signals and circuits, see FIG. 6, and the circuits are composed of an operational amplifier U1A, diodes D1-D4, capacitors C1-C5, resistors R1-R7, variable resistors RP1 and RP2, +15V, -15V and a ground power supply; referring to fig. 2, the CN1 plug is connected to the CN4 plug on the Main Circuit and Power board (Main Circuit + Power-PCB); FL +, FL-signal ends, IFB signal ends, +15V, -15V and ground power supply are connected to a CN1 plug; the FL and FL signal ends are respectively connected to the high signal end and the low signal end of a current divider FL in the output loop of the welding machine, the two ends are connected with an R1 resistor in parallel, the FL end is also connected with C2 and R2, the other end of the C2 is grounded, the other end of the R2 is connected with the inverting input end of U1A, and two diodes D1 and D2 in opposite directions are connected between the inverting input end and the ground in parallel; the FL + end is also connected with C1 and R3, the other end of C1 is grounded, the other end of R3 is connected with the non-inverting input end of U1A and R4, two diodes D3 and D4 in opposite directions are connected between the non-inverting input end and the ground in parallel, and the other end of R4 is grounded; the power supply of U1A is +15V, -15V, they connect 8 feet, 5 feet of U1A respectively, connect C4, C3 decoupling capacitance between U1A's 8 feet, 5 feet to ground respectively; the inverting input end of U1A is connected with pins 3 of R5, C5, R7 and RP1, the other ends of R5 and C5 are connected with the output end of U1A, the end is also an IFB or ADCI2 signal end, and the signal can be transmitted to a Main Circuit and a Circuit part of a Power panel (Main Circuit + Power-PCB) through a CN1 plug; the output end of the U1A is also connected with R6, and the other end of R6 is connected with a pin 1 and a pin 2 of RP1, wherein the pin 2 is the middle sliding point of RP 1; the other end of R7 is connected with the middle sliding point of the 2 feet of RP2, the 1 foot of RP2 is connected with-15V, and the 3 foot of RP2 is connected with + 15V; the circuit of the U1A part can realize sampling and amplification processing of output current signals of the welding machine, and the obtained signals IFB or ADCI2 can be transmitted to a microprocessor for analog-to-digital conversion and finally participate in control processes such as output current negative feedback of the welding machine and the like; the RP1 and RP2 variable potentiometers are used to correct or eliminate differences in the display and actual output current data of the welder and to maintain consistency between the two.
For the part of a liquid crystal Display and Operation control panel (Operation + Display-PCB), the control panel is provided with a liquid crystal Display screen, a key welding method selection key, a welding gun switch Operation mode selection key, a wire detection or wire test feeding/gas detection or gas test feeding selection key, a parameter option selection key and a parameter regulator when seen from the outside of the welding machine; below this liquid crystal display, be provided with: 1) a welding method selection key of gas shield welding (MIG/MAG)/argon arc welding (TIG)/manual welding (MMA), wherein the welding method selection key of gas shield welding (MIG/MAG)/argon arc welding (TIG)/manual welding (MMA) is used for selecting corresponding three welding methods, and the selected state is indicated on the liquid crystal screen through corresponding welding method symbols (such as MIG, TIG and MMA); 2) a 2T/4T gas shield welding torch switch operation mode selection key, which is used for selecting the 2T or 4T operation mode of the gas shield welding torch switch and indicating the selected state on the liquid crystal screen through corresponding symbols (such as 2T and 4T); the 2T mode is that a welding gun switch is pressed down to start gas shielded welding, and the welding is stopped when the welding gun switch is released; the 4T mode is that a welding gun switch is pressed down, gas shielded welding is started, the welding gun switch is released, welding is continuously kept, the welding gun switch is pressed down again, welding is ready to be finished, and welding is stopped when the welding gun switch is released; 3) a selection button of 'wire detection' or 'wire test feeding'/'gas detection' or 'gas test feeding', when selecting operation, the selection button will pass through phase on the liquid crystal screenThe corresponding wire detection or test wire feeding (such as the upper and lower circles and the middle straight arrow)
Symbol)/"gas detection" or "gas test" symbol (e.g. a gas cylinder with three dashed short lines at its top
Symbol) indicates the selected state; the wire detection or wire trial feeding function can be used for detecting whether the wire feeding is normal or not in gas shielded welding (MIG/MAG), and can also be used for realizing the slow or intermittent feeding of the welding wire under the action of a control circuit in the process of installing the welding wire in the MIG/MAG, so that the welding wire can be conveniently installed to extend out of the head of the welding gun; the function of gas detection or gas test can be used for detecting whether the gas supply is normal or not in the process of gas shield welding (MIG/MAG) and can also be used for matching with the flow regulation of a gas flowmeter.
On the right side of the liquid crystal display screen, are provided with: 1) a parameter option key; 2) a parameter adjusting encoder. In the case of the manual welding (MMA) method chosen, the adjustable parameters are the welding current (in A), the thrust current (through the thrust current in the LCD panel)
The symbolic expression of (a) represents that the thrust current is selected), and other welding parameters (such as arc striking current) are set through the control software in a built-in mode without self adjustment of a user; in the case of a selected argon arc welding (TIG) method, the adjustable parameter is the welding current; in the case of the choice of the gas-shielded welding (MIG/MAG) method, the adjustable parameters are the welding voltage (in V), the welding current (in A) or the wire feed speed (by displaying "two circles above and below and a straight line in the middle" in a liquid crystal screen
The expression of symbol represents that the wire feeding speed and the inductance (displayed in a liquid crystal screen) are selected
"symbolized, meaning that the inductance parameter was selected).
The 'option parameter' key is used for selecting the corresponding adjustable welding parameters under each welding method; and the welding parameter adjusting knob is used for adjusting the welding parameters selected by the user under each welding method.
In the liquid crystal panel, a liquid crystal layer is formed,
the indication of the warning symbol is used to indicate whether an over-temperature or over-current condition has occurred; for overheating protection, the temperature relay is installed close to the surface of the IGBT radiator, and when the temperature of the radiator of the internal IGBT is too high and exceeds the action temperature of the temperature relay, an overheating phenomenon can be indicated by lightening a warning symbol under the action of the control circuit; on the other hand, the welding machine can stop welding or output current, and under the condition that the welding machine does not output current, the temperature of the IGBT radiator which generates heat can be reduced by the action of the cooling fan. When the temperature is reduced to the recovery action temperature of the thermal protector, the thermal protector recovers, the welding machine overheating phenomenon is eliminated, and the warning symbol indicates to be extinguished. Meanwhile, the welding machine can be used for welding again. The design is convenient for the selection and use of the welder operator. For overcurrent protection, if the welder detects an overcurrent phenomenon in the working process, the indication can be carried out through a warning symbol, and meanwhile, the control circuit can also close the output of the welder. At this time, the user needs to reduce the current for use, and the power switch is closed again after the power supply is closed, so that the welding machine can be used again. If the warning indicates failure to extinguish, a fault is indicated in the control circuitry of the welder.
The control circuit board is used for displaying and operating the liquid crystal display. This circuit portion is connected to the CN4 plug of the Main Control-PCB circuit portion of fig. 2 of the welder through the CN1 plug of fig. 5. As shown in fig. 5, the circuit on the lcd display and operation control circuit board mainly includes a U1 microprocessor (MC96F6432Q), a lcd YJ1, a "GAS detection" (CHECK GAS) and "wire detection" (CHECK WIRE) key K3, a MIG (GAS shield welding)/TIG (argon arc welding)/MMA (manual welding) three welding method selection key K1, a 2T/4T welding gun switch operation mode selection key K2, a parameter Options (Parameters Options) key K4, a parameter adjustment encoder BMQ, a control board connection interface CN1, a program writing interface J2, NPN type triodes Q1 to Q82 4, an inductance parameter adjustment control circuit (including JDQ 56 to JDQ3 relays and R16, R17 and R18 resistors), resistors R1 to R12, R12 to R12, capacitors C12 to C12, and capacitors E12 to 12; pin 39 of U1 is grounded; pin 38 of U1 is connected with + 5V; decoupling capacitors C1-C2 and filter electrolytic capacitors E1-E2 are connected between +5V and ground; +5V comes from the Main Control board (Main Control-PCB) part through CN1 interface; the J2 socket is a programming interface of the control program of the U1 microprocessor, the pin 4 of the J2 socket is connected with +5V, the pin 3 of the J2 socket is grounded, the pin 2 of the J2 socket is connected with the DSCL terminal of U1, and the pin 1 of the J2 socket is connected with the DSDA terminal of U1; the RXD0 terminal of U1 is connected with R21, the other end of R21 is connected with the RXD1 terminal and C5 of a CN1 socket, and the other end of C5 is grounded; the terminal TXD0 of the U1 is connected with the terminal R22, the other terminal of the terminal R22 is connected with the terminal TXD1 and the terminal C6 of the socket CN1, and the other terminal of the terminal C6 is grounded; by using a plug and a Control line thereof, the two terminals are in serial port communication with a U2 microprocessor (MC96F8316D) of a Main Control board (Main Control-PCB) part of the welding machine, so that data between a liquid crystal display and operation Control circuit and a Main Control circuit of the welding machine, such as welding parameters, actual no-load voltage, welding voltage and the like, can be exchanged in real time; the 42-pin KEY1 wiring end of U1 is connected with R23 and R24 which are connected in series between the ground, the middle connecting point of R23 and R24 is connected with 1 pin and 4 pins of a KEY K1, and 2 pins and 3 pins of K1 are connected with + 5V; the 35-pin KEY2 wiring end of U1 is connected with R25 and R26 which are connected in series between the ground, the middle connecting point of R25 and R26 is connected with 1 pin and 4 pins of a KEY K2, and 2 pins and 3 pins of K2 are connected with + 5V; the 34-pin KEY3 wiring end of U1 is connected with R27 and R28 which are connected in series between the ground, the middle connecting point of R27 and R28 is connected with 1 pin and 4 pins of a KEY K3, and 2 pins and 3 pins of K3 are connected with + 5V; the 31-pin KEY4 wiring end of U1 is connected with R29 and R30 which are connected in series between the end to the ground, the middle connecting point of R29 and R30 is connected with 1 pin and 4 pins of a KEY K4, and 2 pins and 3 pins of K4 are connected with + 5V; one large pin of R1 is connected with pin A2 of U1, the other end of R1 is connected with the bases of triodes of R2 and Q1, the emitter of Q1 is grounded, the collector of Q1 is connected with A1 and R3, the other end of R2 is grounded, and the other end of R3 is connected with + 5V; one large end of R4 is connected with a pin B2 of U1, the other end of R4 is connected with bases of triodes of R5 and Q2, an emitter of Q2 is grounded, a collector of Q2 is connected with B1 and R6, the other end of R5 is grounded, and the other end of R6 is connected with + 5V; one large end of R7 is connected with a pin C2 of U1, the other end of R7 is connected with bases of triodes of R8 and Q3, an emitter of Q3 is grounded, a collector of Q3 is connected with C1 and R9, the other end of R8 is grounded, and the other end of R9 is connected with + 5V; one large of R10 is connected with a 32-pin BGD2 of U1, the other end of R10 is connected with bases of triodes of R11 and Q4, an emitter of Q4 is grounded, a collector of Q4 is connected with R12, the other end of R11 is grounded, and the other end of R12 is connected with a 22-pin BGD1 of a YJ1 liquid crystal screen; the 1 pin of the digital encoder BMQ for parameter adjustment is connected with R33, R34 and a decoupling capacitor C7, the other end of R33 is connected with +5V, the other end of R34 is connected with a 4 pin PULSE of U1, and the other end of C7 is grounded; the 2 pin of the BMQ is grounded; the 3-pin of the BMQ is connected with R36, R35 and a decoupling capacitor C8, the other end of R36 is connected with +5V, the other end of R35 is connected with a 5-pin DIR of U1, and the other end of C8 is grounded; pins 1 and 3 of the BMQ are parameter signal output ends of the encoder; the 4 and 5 pins of the BMQ are KEY connection ends of the encoder, the 4 pin of the BMQ is connected with +5V, the 5 pin of the BMQ is connected with R31 and R32, the other end of R32 is grounded, the other end of R31 is connected with a 30-pin KEY5 of U1, and the KEY is used as a spare KEY for developing a new welding machine; one end of R16 is connected with an L1 end of CN1, No. 4 of a normally open contact of relay JDQ1, the other end of R1 is connected with No. 3 of the other end of the normally open contact of relay JDQ1, R1, No. 4 of the normally open contact of relay JDQ1, the other end of R1 is connected with an L1 end of CN1, that is, the contacts of JDQ1, JDQ1 are respectively connected in parallel with R1, and the operating states of different relays can make resistance values at two ends of L1 different, there can be 1-8 different combination forms, representing variation of 8 inductance parameters, one end of JDQ1, q1, one end of JDQ1, one end of a coil is connected with +5V, a coil B of JDQ1, and the other end of JDQ1 is connected with different control signals, and the control parameters are determined by different control parameters, and final control parameters are determined by different control signals; 6-9 pin COM 1-COM 4 ends of the U1 are respectively connected with 1-4 pin COM 1-COM 4 ends of the YJ1 liquid crystal screen; the SEG 6-SEG 21 ends of the 14-29 pins of the U1 are respectively connected with the SEG 6-SEG 21 ends of the 5-20 pins of the YJ1 liquid crystal screen; a 21 pin of the YJ1 liquid crystal screen is connected with +5V, a 22 pin BGD1 of the YJ1 liquid crystal screen is connected with R22 and controlled by a BGD2 control signal end of U1, when the BGD2 end of U1 outputs high level, a Q4 triode is conducted, BGD1 is grounded through R12, and the backlight source of the liquid crystal screen can be lightened;
the function of this part of circuit is: 1) the selection and control of three welding methods of MIG/MAG (gas shielded welding)/TIG (argon arc welding)/MMA (manual welding) are realized, and the switching and control of the three welding methods are realized by detecting the state of a key K1 through a U1 microprocessor control system. Every time the key K1 is pressed, a welding method is changed. When the key is operated for multiple times, different welding methods are changed sequentially and circularly; 2) and 2T/4T welding gun switch operation mode selection and control are realized. Under the condition of selecting MIG/MAG gas shielded welding, the U5 microprocessor control system realizes the function conversion of two (2T and 4T) welding gun switch operation modes by detecting the state of a key K2. The 2T or 4T torch switch mode of operation changes once per key press of K2. When the key is operated for multiple times, the key is changed in sequence and in a circulating way; 3) the selection and control of gas detection and silk detection are realized; 4) the selection and the regulation control of the corresponding welding parameters under each welding method are realized; 5) various states of the welding machine and given welding parameters (such as wire feeding speed of gas shielded welding or current, voltage and inductance; current for manual welding, thrust current; current for argon arc welding); the change of inductance parameters can affect the arc characteristics during gas shielded welding, thereby changing the welding process, stability, splash size, weld seam formation and the like; the welding voltage can be finely varied between + -5V of the standard value. Meanwhile, the welding voltage and the welding current or the wire feeding speed are set in an integrated adjusting mode, namely the wire feeding speed or the welding current is changed, and the corresponding welding voltage standard value can be changed accordingly. And the trimming welding voltage can play a role of increasing or decreasing on the basis of a standard value. The method is also beneficial for users to properly adjust the welding parameters according to the actual welding conditions; 6) the real-time welding parameters of current and voltage are displayed; serial port communication is carried out between a U1 and a U2 microprocessor (MC96F8316D) of a Main Control board (Main Control-PCB) part of the welding machine in the circuit, so that data between a liquid crystal display and operation Control circuit and a Main Control circuit of the welding machine can be exchanged in real time, and the data are used for Control such as display and the like, for example, whether overheating and overcurrent protection information occurs or not is detected by an actual no-load voltage, welding current and voltage detected by a U2 Control system; welding parameter given data are transmitted to a U2 microprocessor control system; 7) and overheat and overcurrent detection and display are realized. And according to the information obtained by the serial port communication, the overheating or overcurrent protection indication is realized. For example, the overheat protection control and indication, the temperature relay is tightly attached to the aluminum alloy radiator of the IGBT, and when the temperature relay acts, the phenomenon of overheat of the main power device is indicated. Meanwhile, a Control circuit of a Main Control board (Main Control-PCB) part can close the PWM output of the welding machine, stop the output current of the welding machine or the welding work and prevent the welding machine from being burnt out due to overheating. Under the effect of cooling blower, after the temperature of aluminum alloy radiator drops to a certain degree, the overheated phenomenon of welding machine inside is eliminated, and when the heat protector resumes, control circuit could continue to output PWM control signal. With the overheat indication removed. Thus realizing the overheating protection of the welding machine; otherwise, no exception occurs.
The main control circuit of the welding machine of the utility model has a circuit schematic diagram divided into two parts, namely a part shown in figure 7 and a part shown in figure 8; in fig. 7, the control circuit of this part mainly includes an overcurrent and overheat protection control circuit, a low-voltage side drive circuit of the IGBT, a PWM control circuit composed of a PWM chip and its peripheral devices, a voltage-doubling control circuit, an electromagnetic gas valve control circuit, a SPOOL wire drawing gun switching signal control circuit, an input voltage switching signal control circuit, a welding gun switching signal detection control circuit, a U2 microprocessor and its signal detection and processing control circuit, a wire feeding voltage and current feedback control circuit, a PWM wire feeding control circuit, and a wire feeding stopping brake or energy consumption braking control circuit; in fig. 8, the control circuit of this part mainly includes a signal sampling and processing control circuit of the output voltage of the welding machine, a current negative feedback and PI (proportion + integration) operation control circuit of manual welding and argon arc welding, a voltage negative feedback and PI (proportion + integration) operation control circuit of MIG/MAG gas shield welding, and an arc-receiving control circuit of MIG/MAG gas shield welding.
Regarding the composition of the overcurrent and overheat protection control circuit and the control process thereof, namely the circuit at the lower left corner of fig. 7 and the working principle thereof; a low-voltage side driving circuit of the IGBT, namely a circuit at the upper right corner part in the figure 7 and the working principle thereof; a voltage doubling control circuit, namely a circuit of a Q10 triode part on the left in FIG. 7; the electromagnetic valve control circuit, i.e. the circuit of the left Q9 triode portion in fig. 7, has already been described in the foregoing content, and will not be repeated here.
In this section of this specification, the composition and the operation principle of the other circuits are mainly described, and the specific description is as follows:
1) IN fig. 7, the control circuit of the SPOOL wire drawing gun switching signal mainly comprises signal detection ends of resistors R118 and R119, a capacitor C71 and an IN 2; the European/wire drawing type welding gun change-over switch (a serial number 6 IN figure 1) is connected to a vertical middle partition board IN the welding machine through a MIG/SPOOL plug, a pin 2 of the MIG/SPOOL plug is grounded, a pin 1 of the MIG/SPOOL plug is connected with C71, R118 and R119, the other end of the R118 is connected with +15V, the other end of the C71 is grounded, and the other end of the R119 or an IN2 signal detection end is connected with a pin 6 of a U2 microprocessing controller; the U2 microprocessor controller can know whether the user selects the European gas shield welding gun or the SPOOL wire drawing gas shield welding gun by detecting the high and low level states of the 6 pin or IN2 signal; when the European/wire drawing type welding gun change-over switch is switched, the wire drawing gun switching device is correspondingly communicated with a wire feeding motor of a welding machine or a wire drawing gun motor connecting wire of an MIG/SPOOL socket below a front panel through a connecting wire of the switch.
2) An input voltage conversion switch signal control circuit, IN fig. 7, the control circuit of this part mainly includes resistors R120 and R121, capacitors C72 and IN3 signal detection terminals; the 2 pin of the 120V/240V plug is grounded, the 1 pin of the plug is connected with C72, R120 and R121, the other end of the R120 is connected with +15V, the other end of the C72 is grounded, and the other end of the R121 or the IN3 signal detection end is connected with the 11 pin of the U2 micro-processor controller; the U2 microprocessor controller can know whether the user selects 110V-120V input power supply or 220V-240V input power supply by detecting the high and low level states of the 11 pin or IN3 signal; if the signal is the former, the U2 microprocessor can realize voltage-doubling conversion control through the output of the 03 signal; if the latter is the case, the output of the 03 signal does not operate the voltage doubling circuit, i.e., the voltage doubling conversion control is not performed.
3) In fig. 7, the control circuit of the welding gun switching signal detection control circuit mainly comprises resistors R1, R2, R107 and R108, diodes D1 and D2, capacitors C1-C3 and an optical coupler U1; GUN Switch is a welding GUN Switch connecting wire socket which can be connected to Switch control wires of European and SPOOL wire drawing welding GUNs through a plug and a control wire thereof; the 3 pins of the plug are grounded, the 1 pin of the plug is connected with the cathodes of C2, C3 and D2, the anode of D1, the cathodes of light emitting diodes in R2 and U1, the anodes of C2, C3 and D2 are grounded, the cathode of D1 and the other end of R2 are connected with the anodes of light emitting diodes in R1 and U1, and the other end of R1 is connected with a +15V1 power supply; the collector of an output triode IN U1 is connected with C1, R107 and R108, the emitter of the output triode IN U1 is grounded with the other end of C1, the other end of R107 is connected with +5V, and the other end of R108 is connected with a pin 14 of a U2 microprocessor or an IN1 control signal detection end; the U1 optical coupler is used as an electrically isolated optical coupler; if the pin 1 of the GUN Switch plug is grounded, namely the welding GUN Switch is closed, the light emitting diode IN the U1 emits light, the output stage triode is conducted, the U2 microprocessor can detect that the pin 14 or IN1 control signal is low level, and can know that the welding GUN Switch is closed, and then the U2 control system can send out a corresponding control instruction, for example, a 01 signal is output, so that the electromagnetic air valve works to carry out advanced air supply control; outputting a 02 signal, and not closing the PWM signal output of the U13 to enable the welding machine to have output voltage and current; outputting 04 signals, and not starting the arc-extinguishing control process below the graph 8; outputting a 05 signal to enable a Q7 triode at the lower part of the graph 8 to be conducted, enabling an RLY2 relay to act, disconnecting a two-stage PI control circuit used during manual arc welding and argon arc welding, and communicating the PI control circuit used during gas shielded welding to realize the output characteristic and welding control of the gas shielded welding; outputting 06 signals to carry out wire feeding control of gas shielded welding; on the contrary, if the welding gun switch is detected to be disconnected again, the control process is basically different, and processes such as 2T or 4T control difference, gas lag gas closing, arc closing control and dynamic braking processing of stopping feeding of welding wires exist. In addition, when the 'CHECK GAS' (CHECK GAS) and 'CHECK wire' (CHECK WIRE) keys K3 are used for selecting the 'CHECK GAS' (CHECK GAS) operation, the U2 control system can send out a corresponding 01 signal control command, and the electromagnetic air valve can work by combining the electromagnetic air valve control circuit of the small control panel part, so that the 'CHECK GAS' or air supply control is realized, and when the 'CHECK GAS' (CHECK GAS) operation is not selected, air supply is stopped; when the wire detection (CHECK WIRE) operation is selected, the U2 control system sends out a corresponding 06 signal control command, meanwhile, air supply and welding machine output control are not carried out, the wire feeding motor can work to realize wire detection or wire feeding control by combining the circuit working principle description of the wire feeding control part, and wire feeding is stopped when the wire detection (CHECK WIRE) operation is not selected.
4) A U2 microprocessor and its signal detection and processing control circuit, IN fig. 7, the control circuit of this part includes a U2 microprocessor, a programming interface circuit (see the connecting circuit part of CN12 interface IN fig. 7), an INAC signal (the explanation of this signal is see the switching power supply circuit and its operation principle IN fig. 3), an ADCI2 or IFB output current feedback signal (see the explanation about this signal IN the previous Small control board (Small-PCB) circuit part), an ADCV2 output voltage signal (see the explanation about CN9 interface, U3 operational amplifier circuit and U5 linear optical coupler conversion circuit and U101C and U101D operational principle IN fig. 8 later), and the sampling of IN1 to IN4 signals, and the output control of 01 to PPG 06 signals; the INAC signal is connected with R101 and R102, the other end of R101 is grounded, the other end of R102 is connected with pin 27 of U2, and the U2 microprocessor can sample the INAC signal and detect the working condition of the switching power supply; the ADCI2 or IFB output current feedback signal is connected with R113, R112 and C63, the other ends of R112 and C63 are grounded, the other end of R113 is connected with a pin 25 of U2, and the U2 microprocessor can sample the ADCI2 or IFB output current feedback signal for control of display and the like; the output voltage signal of ADCV2 is connected with R115, R114 and C64, the other ends of R114 and C64 are grounded, the other end of R115 is connected with pin 26 of U2, and the U2 microprocessor can sample the output voltage signal of ADCV2 for control of display and the like; of course, through the control line connection of the CN4 plug, the U2 microprocessor also performs a serial port communication part with the microprocessor of the liquid crystal display and operation control board, so as to realize data exchange between two microprocessor systems, such as data exchange of given signals of welding parameters such as current and voltage, and feedback signals; IN4 is an over-temperature and over-current detection signal, many of the other signals and their control actions described above, are described IN the preceding paragraphs and will not be repeated here. The following description will be made accordingly, even if it is not further described herein.
5) A PWM control circuit, as shown in fig. 7, the control circuit of this part mainly comprises a U13(SG3525) PWM chip, and its peripheral resistors (e.g., R132, R133, R147 to R149, and R168) and capacitors (e.g., C76 to C83) components; the inverter PWM pulse width modulation part outputs two groups of PWM pulse signals with certain dead time through pins 11 and 14 of the U13, and the on-off states of two groups of IGBT switching tubes in the inverter half-bridge main circuit are respectively controlled through a low-voltage side driving circuit and a high-voltage side driving circuit of the IGBT. The pulse width of the PWM signal is controlled by the U13-2, i.e., the 2 pin input signal of the U13 chip. The presence or absence of the PWM signal output is controlled by the input signal of the pin 8 of the U13-8, namely the U13 chip. More information about this part of the circuit has already been explained in the preceding text and will not be repeated here.
6) Wire feed voltage and current feedback control circuitry, fig. 7 and 8, the control circuitry of this portion, includes: a) the power supply circuit of the wire feeding motor mainly comprises diodes D7 and D9 in the figure 8, resistors R13 and R20, an electrolytic capacitor C15, a plug CN9 and MOTO; the plug CN9 is connected to the output end of the welding machine, the plug MOTO is connected to the two ends of the armature of the wire feeding motor of the welding machine, and the power supply of the motor is taken from the output voltage VCC1 of the welding machine according to the circuit of the part; d9 rectification, C15 filtering and D7 diode as freewheeling diode to eliminate the adverse effect of the back-emf of the wire-feeding motor on Q2; r13 current limiting and voltage dropping; b) the armature voltage negative feedback signal detection and processing circuit consists of resistors R36, R49, R50, R41, R42, R44, R50 and R52, capacitors C23, C26-C28 and an operational amplifier U4; the non-inverting input end of U4 is connected with R46, the end is connected with C28 and R52 in parallel between the ends of the two ends to the ground, R46 is connected with C27 and R49, the other end of R49 is connected with the positive polarity M + end of the motor, the other end of C27 is connected with R42 and R41, the other end of R42 is connected with the negative polarity M-end of the motor, the other end of R41 is connected with the inverting input end of U4, the end is connected with R36 and C23 in parallel between the output end of U4, the output end of U4 is connected with R44, the other end of R44 is connected with R50 and C26, the other end of C26 is connected with the ground, and the other end of R50 is connected with U8-1, namely pin 1 of U8(TL494) PWM chip; the signals at the two ends of M + and M-are the armature voltage of the wire feeding motor, therefore, the detection signal obtained by U8-1 is the voltage negative feedback control signal of the wire feeding motor; a wire feeding motor with the rated voltage of 24V is connected between M + and M-, and the wire feeding motor belongs to a component of the wire feeding mechanism in the figure 1; when output voltage exists between the M + terminal and the M-terminal, the wire feeding motor connected to the interface is operated, wire feeding control can be realized, otherwise, the wire feeding motor cannot rotate and cannot feed wires; c) when the motor works, current feedback signals of the motor are taken out by R29-R33 connected in series in an armature loop of the motor, detection signals are obtained through a connected R80 resistor and are connected to the input end of R83, and finally, a U8-16 pin is provided, and a C41 capacitor connected between a connecting point between R80 and R83 and the ground carries out signal filtering; when the motor works, if the wire feeding resistance is increased, the wire feeding speed is reduced, the current of the motor can be increased, and the wire feeding speed of the motor can be increased through current feedback, so that the effect of positive feedback or compensation control of armature current is achieved. The armature voltage negative feedback and the armature current positive feedback or compensation control are adopted, so that the method plays an important role in stably controlling the wire feeding speed during gas shielded welding of the welding machine, and the important premise of ensuring the stability of the welding process is provided.
7) A PWM wire feeding control circuit, in FIG. 7, the control circuit of this part mainly includes a U8(TL494) PWM chip, U7 and U9 optocouplers, NPN type triodes Q3 and Q4, a relay RLY1, diodes D11 and D20, 06 control signals, a variable resistor RP3, and a peripheral resistor and a peripheral capacitor; 06 signals come from a pin 19 of a U2 microprocessing controller, the pin is connected with R53, R53 is connected with the base of Q4, the emitter of Q4 is grounded, the collector of Q4 is connected with the anodes of R40, R47 and D18 and the cathode of a light-emitting diode in a U7 optical coupler, the cathode of D18 is connected with the anode of the light-emitting diode and R45, the other end of R45 is connected with +15V, the other end of R47 is connected with the base of Q3, the emitter of Q3 is grounded, the collector of Q3 is connected with one end of a coil of a relay RLY1, the other end of the coil is connected with R22, the other end of R22 is connected with +15V, and the two ends of the coil are connected with D11 in an anti-parallel mode; the D11 diode is used to eliminate the adverse effect of the back-emf of the relay coil on it; the middle point of a contact part of the relay RLY1 is connected with M-, the other point is connected with R16, the other end of R16 is connected with M +, R16 is a 22 ohm 5 watt resistor used for braking the motor, and the other point is connected with the 2 pin or D end of a field effect transistor Q2; an emitter of an output stage triode of the U7 optocoupler is grounded, a collector of the triode is connected with R54, C31 and U8-4 (DTC soft start control of U8), the other end of C31 is grounded, and C31 is a soft start control capacitor; the other end of the R54 is connected with an internal reference voltage end of U8-14 (Vref); the cathode of a light-emitting diode in the U9 optical coupler is grounded, the anode of the diode is connected with R62, the other end of R62 is connected with a PWM2 control signal end, and the control signal end is connected with a pin 21 of a U2 microprocessor and is also a given control signal of wire feeding speed; the collector of an output triode of the U9 optocoupler is connected with R59, and the other end of R59 is connected with an internal reference voltage end of U8-14 (Vref); an emitter of an output stage triode of the U9 optocoupler is connected with R66, R72 and R76, the other end of R76 is grounded, the other end of R72 is connected with a middle sliding point of a variable resistor RP3, the middle sliding point is connected with a pin 1 of RP3, a pin 3 of RP3 is connected with an anode of D20, and a cathode of D20 is grounded; the other end of R66 is connected with C37 and R64, the other end of C37 is grounded, the other end of R64 is connected with C33, C35 and U8-2, the other end of C35 is connected with U8-3, the other end of C33 is connected with R73, and the other end of R73 is connected with U8-3; since the pins 1, 2 and 3 of the U8 are the connecting terminals of the U8 internal operational amplifier, the pin 1 is the non-inverting input terminal IN +, the pin 2 is the inverting input terminal IN-, and the pin 3 is the output terminal FB of the operational amplifier, from the external connection, the serial connection of C33, R73 and C35 is parallel connected between the inverting input terminal and the output terminal of the internal operational amplifier, which is the feedback network of the operational amplifier, and the circuit of the part constitutes the PI (proportional plus integral) operation circuit for wire feeding control, and an input signal of the circuit is the input signal of R64, which is also the given signal for wire feeding speed control; the other input signal is the input signal from R50, namely the armature voltage negative feedback signal of the wire feeding motor, because the former given signal is connected with the inverting input end of the operational amplifier and the latter signal is connected with the non-inverting input end thereof, the control action of the two signals is opposite, and therefore, the armature voltage detection signal forms negative feedback control; IN addition, as mentioned above, the feedback signal of the armature current is connected with the U8-16 through a circuit, the feedback signal is the inverting input end of another operational amplifier IN the U8, the non-inverting input end of the operational amplifier is 15 pins IN +, the non-inverting input end of the operational amplifier is connected with the R81 and the R74, the other end of the R81 is grounded, and the other end of the R74 is connected with the U8-14(Vref) internal reference voltage end; the op-amp is output either U8-3 or FB, whereby it can be seen that the current feedback signal is similar in control polarity or action to the given signal input by R64, i.e. the current feedback constitutes a positive feedback or compensation control; RP3 is used to correct or fine-tune the wire feed speed; PWM control signals output by a pin 9 and a pin 10 of the U8 chip control a Q2 MOS tube after passing through a post-stage control circuit; the on-off time of the Q2 MOS tube is controlled, so that the rotating speed of the wire feeding motor is controlled; the width of the PWM control pulse is determined by a wire feeding speed set value, an armature voltage negative feedback signal and a current positive feedback or compensation control signal, for example, the pulse width can be changed by changing the wire feeding speed set value, and finally the wire feeding speed is changed, wherein the wire feeding speed set value represents the wire feeding speed or current control in gas shielded welding; the pins 9 and 10 of the U8 output PWM pulse width regulation control signals, and because the output power is not large, a circuit formed by an NPN type triode Q5, a PNP type triode Q6 and peripheral devices thereof is utilized for signal amplification, and then a field effect transistor Q2(IRF640S) is controlled, so that the size of the armature voltage of the wire feeder is controlled and regulated, the wire feeding speed regulation is realized, and the speed stabilization control is realized under the action of negative feedback and positive feedback; u8-9/10 is connected with bases of Q5 and Q6, R86, the other end of R86 and a collector of Q6 are grounded, an emitter of Q6 is connected with R82, the other end of R82 is connected with a control or grid G end of a Q2 field effect transistor, a ZD3 voltage regulator tube is connected between the end and an S end of Q2 in an anti-parallel mode, namely, a cathode of ZD3 is connected with the G end, the S end of Q2 is also connected with resistors connected in parallel with R80, R29-R33, the resistors in parallel are motor current feedback signal sampling resistors, and R80 inputs feedback signals to an input signal end of U8-16; the D end (Q2-2) of Q2 is connected with the No. 3 point of the contact of a relay RLY1, and the contact of the relay can be connected with the Q2-2 and the M-end when the relay is operated during wire feeding control; r23, C20 and C21 which are connected in series are also connected in parallel between ends D, S of the Q2; the emitter of the Q5 is connected with the R79, the other end of the R79 is also connected with the G end or the grid control end of the Q2, the collector of the Q5 is connected with a +15V1 power supply, and a C14 filter capacitor and a C36 filter capacitor are connected between the power supply and the ground in parallel; when the U8-9/10 end outputs PWM pulse width modulation signals, the Q2 can be in the on-off changing state, the armature voltage of the motor is different according to different PWM pulse widths, and therefore the rotating speed or the wire feeding speed of the motor is different. The wire feeding speed is adjusted and controlled; when a 06 signal end outputs a high level, Q4 is conducted, Q3 is cut off, a relay RLY1 does not act, contacts 1 and 3 of the relay RLY1 are in a normally closed state, a braking resistor R16 cannot be connected to a motor circuit, a light emitting diode in U7 emits light, a triode of an output stage of the light emitting diode is conducted, the level of a pin 4 (DTC end) of a U8 PWM chip is pulled down to a low level, and the ends U8-9/10 are started to output PWM pulse signals; the wire feed speed depends on the PWM2 wire feed speed setting, the armature voltage and the magnitude of the current feedback; on the contrary, when the 06 signal end outputs a low level, Q4 is cut off, Q3 is conducted, relay RLY1 is operated, contacts 1 and 2 of relay RLY1 are conducted, brake resistor R16 is connected to a motor circuit, a light emitting diode in U7 does not emit light, a triode of an output stage is cut off, the level of a 4 pin (DTC end) of a U8 PWM chip is a high level, a PWM pulse signal is output from a U8-9/10 end, and wire feeding is stopped.
8) In fig. 7, the control circuit of this part is the control circuit for controlling whether the braking resistor R16 is connected to the motor, and it has been described in the above description that when the signal end 06 outputs a low level, Q4 is turned off, Q3 is turned on, the relay RLY1 is operated, the contacts 1 and 2 of the relay RLY1 are connected, and the braking resistor R16(22 ohm 5 watt) is connected to the motor circuit, so that the energy of the wire feeding motor can be consumed quickly, the dynamic braking is performed, and the welding wire is prevented from possibly rushing out of the contact tip of the welding gun to enter the molten pool too long and the so-called wire sticking phenomenon occurs when the welding is stopped by the control of the welding gun switch. In addition, the arc striking control of the next gas shielded welding can be influenced by the fact that the welding wire extends out of the contact tube for too long.
Outputting the given signal and its associated circuitry. The different welding methods are different for outputting a given control signal. A) For MIG/MAG gas shielded welding, the main objective of control is the output external characteristic of the welder, i.e. the output voltage versus output current, i.e. the often flat characteristic output, given the control signals of this welding method: outputting a voltage given signal, outputting current or wire feeding speed, adjusting voltage given, and changing welding voltage; by adjusting the wire feeding speed, the welding current can be changed; the wire feed control circuitry has been described above with respect to how wire feed speed is affected by a given wire feed speed. And will not be described in detail herein. B) For MMA manual arc welding, the main objective of control is also the output external characteristic of the welder, i.e. the output voltage versus output current, but quite different from MIG/MAG gas shield welding, which is the often-said constant current out-of-band pull droop characteristic, given the control signals of this welding method: welding current setting signals and thrust current setting signals. The thrust current refers to the current output by the welding machine when the welding voltage is lower than 16V or the current of an external dragging part in an external characteristic curve, and is also the current increased relative to the external characteristic constant current section part when the welding voltage is low; the welding current given signal is adjusted, so that the welding current can be changed; the given signal of the thrust current is adjusted, so that the magnitude of the thrust current can be changed, the molten drop transition process, the arc striking and the welding performance of welding can be improved, and even the capital and other performance indexes of welding spatter can be changed; C) for TIG argon arc welding, the main target of control is also the output external characteristic of the welding machine, i.e. the relation between output voltage and output current, but is different from that of MMA manual welding, i.e. the constant current drop characteristic in general, and the given control signals of the welding method are as follows: the welding current gives a signal, and no thrust current is controlled; the welding current given signal is adjusted, so that the welding current can be changed; regarding the above-mentioned given signals, the microprocessor system of the liquid crystal display and operation control panel circuit part samples the related given signals, the related given signals are communicated through the serial port, the data are sent to the U2 microprocessor controller in fig. 7 and are output to the related control circuit part by the U2 microprocessor, for example, the PWM2 output by pin 21 of U2 in fig. 7 is the wire feeding speed given signal; the PPG signal output at 22 of U2 in fig. 7 is a welding parameter given signal, which is not synonymous for different welding methods, even if the same method, is different at different control stages. For example, for the MMA manual welding method, the PPG signal output by U2 when the welding voltage is above 16V is a given signal of the welding current, and the PPG signal output when the welding voltage is below 16V is a given signal of the thrust current; for TIG argon arc welding, a PPG signal output by U2 is a given signal of welding current; for MIG/MAG gas shielded welding, in the arc starting, welding and arc stopping control stages, the PPG signal output by the U2 is an output voltage given signal of the welding voltage corresponding to different stages, and meanwhile, the U2 can also output different wire feeding speed given PWM2 signals in cooperation with different stages.
The pin 2 of the coil of the RLY2 relay is connected with R89, the other end of R89 is connected with +15V, the other end of the coil is connected with the collector of an NPN type triode Q7, and a D21 diode is connected with the two ends of the coil of the RLY2 relay in an anti-parallel mode; the emitter of Q7 is grounded, the base of Q7 is connected with R94 and R91, the other end of R94 is grounded, and the other end of R91 is connected with the 05 control signal end of the U2 microprocessing controller in FIG. 7; 05, the control signal end is a selection control signal end of MIG/MAG gas shielded welding and MMA manual welding/TIG argon arc welding; when the 05 signal end is at a low level, MIG/MAG gas shielded welding is selected for a user; when the signal end 05 is at a high level, MMA manual welding or TIG argon arc welding is selected for a user; the control process of the RLY2 relay is as follows: when a user selects MIG/MAG gas shielded welding by operation, Q7 is cut off, the RLY2 relay does not act, 5 points and 6 points of the contact of the RLY2 relay are connected with 10 points of the contact, and a signal from R85 is an input signal of U16B; when the user selects MMA manual welding or TIG argon arc welding, Q7 is conducted, the RLY2 relay acts, 5 points and 6 points of the contact of the RLY2 relay are connected with 1 point of the contact, and a signal from RP4-1 is an input signal of U16B.
In fig. 7, the PPG signal is connected to R116, and then connected to the non-inverting input terminal of the U16A operational amplifier after passing through a pi-type filter circuit composed of a post-stage R117, C65, and C66; the working power supply of U16 is +15V, -15V; the circuit of the U16 part is a synchronous follower, and the output of the synchronous follower is connected with the non-inverting input end of the U102D; the circuit of the U102D part is a proportioner, and the feedback resistance is R95; the working power supply of the U102 operational amplifier is + 15V-15V; the output of U102D is connected with the non-inverting input ends of R19 and U102A, wherein the PPG signal is divided into two branches after being processed by the U16A synchronous follower and the U102D comparator, one branch is a rear-stage circuit of R19, and the signal is given corresponding to the output voltage of MIG/MAG gas shielded welding; one path is a circuit of the U102A part and corresponds to a welding parameter given signal of MMA manual welding or TIG argon arc welding.
For branch parts of MMA manual welding or TIG argon arc welding, in FIG. 8, a circuit of a U102A part is a proportioner, and a feedback resistor is R90; the output end of the U102A is connected with R87, and the other end of R87 is connected with pin 1 of a variable potentiometer RP 4; the middle sliding point 2 pin and the 3 pin of the RP4 are connected and are connected to the contact 1 point of the relay RLY 2; the variable potentiometer RP4 is also used to fine tune the signal magnitude; when the user selects MMA manual welding or TIG argon arc welding, as Q7 is conducted, the RLY2 relay acts, 5 and 6 points of the contact of the RLY2 relay are communicated with 1 point of the contact, therefore, the signal from RP4-1 is the input signal of U16B; the non-inverting input end of the U16B operational amplifier is grounded, and a feedback network is connected between the inverting input end and the output end of the U16B operational amplifier, wherein the network is in a structure that R159 and C92 are connected in parallel at the two ends; ZD11 stabilivolt is also connected in parallel between these two ends, and ZD11 anode is connected to its output; U16B and its network also constitute PI control circuit; the inverting input end of the U16B is connected with the contacts 5 and 6 of the relay RLY 2; the output end of the U16B is connected with the non-inverting input end of a synchronous follower composed of U16C, the output end signal of the synchronous follower is the input signal of the R160 resistor, the signal and the output current feedback signal of the welding machine from the R164 are subjected to control operation in the PI link composed of the U16D and the network thereof, and finally the signal size of the U13-2 is determined, so that the output current size of MMA manual welding or TIG argon arc welding is determined.
9) The current negative feedback of manual welding and argon arc welding and its PI (proportion + integral) operation control circuit, in figure 8, this part of control circuit, mainly include U103A operational amplifier; the power supply of U103 is + 15V-15V; the feedback signal of the output current of the welder, in fig. 8, is the IFB or ADCI2 current feedback signal, which comes from the Small control board (Small-PCB) of the welder, because the detection and conversion processing circuit of the current signal on this Small board has been already explained in the previous related parts, and will not be described again here; the working power supply of the U103 operational amplifier is + 15V-15V; the IFB or ADCI2 current feedback signal is connected to the non-inverting input end of the U013A operational amplifier through R3, the inverting input end of the U013A is connected with the output end, and the circuit is a synchronous follower circuit; the output end signal of U013A is the output current feedback signal of the welding machine, and is also the important signal participating in the current negative feedback and PI (proportion + integral) operation control during manual welding and argon arc welding; the circuit is connected with R61 and R164, R61 is an input resistor of U103B, the circuit is connected with the inverting input end of U103B, the other input resistor of U103B is R63, and the circuit is connected with the inverting input ends of R60, R71 and U102B operational amplifiers; r164 is an input resistor of the U16D operational amplifier and is connected with the inverting input end of the U16D, the other two input resistors of the U16D are R161 and R160, the other end of the R161 is connected with +15V, and the input of the R160 is the output of the synchronous follower U16C; the non-inverting input end of the U16D is connected with the ground through R162, and a network consisting of a resistor and a capacitor is also connected between the inverting input end of the U16D operational amplifier and the output end 14 pin of the U16D operational amplifier; the structure of the network is that C93 and R165 are connected in parallel, one end of the parallel device is connected with a pin 14 of an output end U16D, the other end of the parallel device is connected with R163, the other end of the R163 is connected with an inverting input end U16D, the feedback network of the operational amplifier is formed, and the operational amplifier circuit of the part is a PI (proportional plus integral) operation circuit; the 14 pin of the output end 14 of the U16D is connected with R166, the other end of the R166 is connected with R167 and R169, the other end of the R169 is grounded, the other end of the R167 is connected with U13-2, namely the 2 pin of the U13 PWM chip in FIG. 7, and the output signal end also controls the pulse width of the output PWM signal of U13; the change of the output control signal of R167 determines the pulse width of the PWM signal output by U13, and ultimately determines the output current or voltage of the welder.
For branch parts of MIG/MAG gas shielded welding, in FIG. 8, the rear end of R19 is connected with the inverting input end of U102C, the non-inverting input end of U102C is grounded, and R21 and C17 feedback networks are connected in parallel between the inverting input end of U102C and the output end of the U102C; the output signal of U102C is the input signal of R14, so the input signal of R19 is also controlled by the PPG signal, therefore, the magnitude of the PPG signal is changed, and the magnitude of the input signals of R19 and R14 are changed, and the output signal of U101A is changed because the given signal and the output voltage feedback signal from R15 are applied to the control element of U101A.
10) A signal sampling and processing control circuit of output voltage of the welding machine, in fig. 8, the control circuit of the part mainly comprises a CN9 socket, a U3 operational amplifier, a U5 linear optical coupler, and peripheral resistor and capacitor components thereof; CN9 is connected to two ends of OUTPUT of welder, CN9-1 is connected to OUTPUT (+) positive OUTPUT end of welder; the negative polarity output end of the capacitor is connected with CN9-2 and is grounded; CN9-1 is connected with R8; the other end of the R8 is connected with the R7, and the end is connected with the ground in parallel with R10 and C13; the other end of R7 is connected with the non-inverting input end of U3, the inverting input end of U3 is connected with the emitter or 4 pin of the triode in C11, R18 and U5, the other end of R18 is grounded, the other end of C11 is connected with the output end of U3, the output end is connected with R9, the other end of R9 is connected with the anode or 2 pin of the LED of U5, the 1 pin of U5 or the cathode of the LED is grounded, and the 3 pin of U5 or the collector of the internal triode is connected with + 15V; the power supply of U3 is +15V and ground; r8 and R10 form a voltage divider circuit, so that the voltage obtained by the later stage is reduced; the U5 plays a role of electrical isolation, prevents the interference of a high-voltage output loop on a low-voltage control circuit so as to ensure the reliability of the work of the circuit, and simultaneously, because of a linear optical coupler, the sampling and the transmission of a post-stage circuit on a welding machine output voltage signal can not be influenced; the collector or 6 pins of the output side triode of U5 are connected with +15V, and a C6 filter capacitor and a C7 filter capacitor are connected between the power supply and the ground in parallel; an emitter or a 5 pin of an output side triode of the U5 is connected with a pin 10 of a non-inverting input end of the C16, the R17 and the U101C operational amplifier, the other end of the C16 is grounded, the other end of the R17 is connected with a pin 3 of the variable potentiometer RP2, and a middle sliding point and a pin 1 of the RP2 are grounded; the RP2 is used for correcting and fine-tuning the output voltage feedback signal size of the welding machine; the pin 9 of the inverting input end of the U101C is connected with the pin 8 of the output end thereof, the output end is connected with the R12, the other end of the R12 is connected with the cathode of the ZD2 voltage regulator tube and the pin 12 of the non-inverting input end of the U101D operational amplifier; ZD2 anode ground, U101D inverting input 13 pin connected its output 14 pin, the output connected R15, R15 other end connected RP 13 pin, RP1 middle sliding point 2 pin and 1 pin connected, and also connected R14, U101A operational amplifier non-inverting input 3 pin; the working power supply of the U101 operational amplifier is +15V and-15V; from the connection relationship of the circuits, in the pin 3 of the non-inverting input terminal of the U101A operational amplifier, one input resistor is R14, and the other input resistor is RP1 variable resistor and R15; the signal connected to the input end of the R15 is an output voltage sampling signal from an output voltage sampling circuit and passing through a voltage division circuit and a U101C and U101D two-stage operational amplifier processing circuit; the signal inputted through the R14 resistor is the welding output voltage given signal in MIG/MAG gas shield welding.
11) In fig. 8, the control circuit of the MIG/MAG gas shield welding voltage negative feedback and its PI (proportional plus integral) operation mainly includes a circuit composed of a U101A operational amplifier and its peripheral components; two diodes D12 and D13 in opposite directions are connected in parallel between the non-inverting input end and the inverting input end of the U101A operational amplifier, and are amplitude limiting diodes; the non-inverting input end of the U101A operational amplifier is connected with an input resistor R14 and a branch thereof, an input resistor RP1 variable resistor, an R15 and a branch thereof; the inverting input end of the U101A is connected with the cathodes of the R39 and D15 diodes, and the anode of the D15 is connected with the pin 14 of the output end of the U103D operational amplifier; a network consisting of a resistor, a capacitor and a voltage regulator tube is connected between the inverting input end of the U101A operational amplifier and the output end pin 1; the structure of the network is that C24, R37 and ZD4 voltage-stabilizing tubes are connected in parallel, one end of the anode of ZD4 in the parallel device is connected with the pin 1 at the output end of U101A, the other end of the parallel device is connected with R38, and the other end of R38 is connected with the inverting input end of U101A operational amplifier; as described above, in the non-inverting input terminal 3 pin of the U101A operational amplifier, one input resistor is R14, and the other input resistor is RP1 variable resistor and R15; the signal connected to the input end of the R15 is an output voltage sampling signal from an output voltage sampling circuit and passing through a voltage division circuit and a U101C and U101D two-stage operational amplifier processing circuit; the signal inputted through the R14 resistor is the welding output voltage given signal in MIG/MAG gas shield welding. According to the connection relationship between the network and the U101A operational amplifier part, the control and operation circuit is a PI (proportion + integration) control operation circuit, and because an input signal at one end of the circuit is an output voltage feedback signal of a welding machine, the U101A control operation link is a PI operation control circuit of MIG/MAG gas shielded welding; the RP1 variable resistor is also used for correction or trimming of the voltage feedback parameter.
The output of U101A is connected with R24 and R28, the other end of R24 is connected with R26 and L1, the other end of R26 is connected with L2, the cathode of D14 diode, the emitter of output stage triode of U6 optical coupler, and the 5 pins of non-inverting input end of R55 and U101B operational amplifier; the other end of the R28 is connected with the anode of the D14 and the collector of an output triode of the U6 optocoupler; the connection between the terminals L1 and L2, described in the previous LCD and operator control panel circuits, is in a loop that changes the welding parameters of the welder's inductance, with the inductance parameters being different for different resistances relative to the connection between the terminals L1 and L2 of "one variable resistor"; the non-inverting input terminal of the U101B is connected in parallel with diodes C25, R48 and D16 between the non-inverting input terminal of the U101B and the ground, the cathode of the D16 is grounded, the 6 pin of the inverting input terminal of the U101B is connected with the 7 pin of the output terminal of the U101B, the part is a synchronous follower circuit, the 7 pin of the output terminal is connected with R60, the other end of the R60 is connected with the anodes of the diodes R63, R71 and D19, the inverting input terminals of the R69 and the U102B, the non-inverting input terminal of the U102B is grounded, and a network consisting of a resistor, a capacitor and a diode is also connected between the inverting input terminal of the U102B operational amplifier and the 7 pin of the output terminal of the U102; the structure of the network is C39 and R77 which are connected in parallel, one end of the parallel device is connected with the output end 1 pin of U102B, the other end of the parallel device is connected with R69, the other end of R69 is connected with the inverting input end of U102B operational amplifier, the cathode of a D19 diode is connected with the output end 1 pin of U102B, and the anode of the D19 diode is connected with the inverting input ends of R60, R71 and U102B operational amplifier; the pin 1 of the output end of the U102B is connected with R85, and the other end of R85 is connected with the contact 10 point of the RLY2 relay; the circuit formed by the U102B and the network thereof is still a PI control circuit; during MIG/MAG gas shielded welding, Q7 is cut off, the RLY2 relay does not act, the 5 and 6 points of the RLY2 relay contact are connected with the 10 points of the contact, and the signal from R85 is the input signal of U16B. This is different from the input signal of U16B when MMA manual welding or TIG argon arc welding. Certainly, during MIG/MAG gas shielded welding, the output current feedback signal of the welding machine is still input to the PI control operation link formed by the U16D through the R164, however, the current negative feedback at this time mainly limits the excessive current output by the gas shielded welding flat characteristic to burn out the device of the welding machine, and therefore, the effect of the current negative feedback under the gas shielded welding is to limit the output current.
12) In the arc-extinguishing control circuit for MIG/MAG gas shielded welding, in the control circuit shown in FIG. 8, the other end of R71 is connected with R70 and R75, the other end of R75 is grounded, the other end of R70 is connected with the collector of a U10 optical coupler output triode, and the emitter of the triode is connected with-15V; the cathode of a light-emitting diode in the U10 optical coupler is grounded, the anode of the diode is connected with R68, and the other end of R68 is connected with the 04 control signal end of the U2 microprocessing controller in the figure 7; the control end is a control signal end for arc-closing process or removing small balls at the end of the welding wire; when the 04 control signal end is at a high level, an output stage triode in the U10 is conducted, 15V is input to a rear stage circuit as a control signal circuit R70, and arc-closing process control is carried out; when the 04 control signal terminal is low, the output stage transistor in U10 is not conductive, 15V is not input to R70, and therefore, there is no arcing process control.
In FIG. 8, the input signal of R61 is the output current feedback signal of the welder; r is connected with the inverting input end of U103, R and C are connected between the inverting input end and the output end of the U103 in parallel, the output of the U103 is connected with R, the other end of R is connected with the inverting input ends of R and U103, the non-inverting input end of U103 is grounded, the other end of R is connected with +15V, a C capacitor is connected between the inverting input end of U103 and the output end of U103, the output end of U103 is connected with the anode of a D diode and the anode of a light emitting diode in a U optical coupler, the other end of the light emitting diode is grounded, the cathode of D is connected with R, the other end of R is connected with the inverting input end of U103, R and C, the other ends of R and R are grounded, the non-inverting input end of R is connected with R, the other end of R is grounded, the other end of R is connected with +15V, U103 is a voltage comparator, the output end of U103 is connected with D, and the cathode of D is connected with the inverting input end of U101; the collector of the triode in the U6 is connected with the anode of the D14, the R28, the cathode of the D14 is connected with the L2 end and the R55 and other devices, and the other end of the R28 is connected with the output end of the U101A; for this part of the circuit, the output of U103C, either +15V or-15V, depends primarily on whether there is welding current at the output of the welder; therefore, the circuit of the part judges whether the output current exists or not and carries out corresponding control process; when welding current is output, the output of the U103C is +15V, a triode in a U6 optocoupler is conducted, and a D14 diode is short-circuited; meanwhile, the output of the U103D is-15V, and the D15 diode is cut off; on the contrary, when no welding current is output, the output of the U103C is-15V, a triode in a U6 optocoupler is not conducted, and a D14 diode is connected into a loop of the R28; meanwhile, the output of the U103D is +15V, and the D15 diode is turned on; the control results are completely different for different states.
For the control of the 2T or 4T mode of operation of the gas shielded welding torch switch, the operation and the control process thereof will not be described in detail, and the following description will be made:
when a welding gun switch is switched on, on one hand, an electromagnetic gas valve is enabled to act to enable protective gas to be conveyed to a welding area at the end of the welding gun for protection, and on the other hand, square wave pulse PWM control signals output by 9 and 10 pins of a U8 chip are used for controlling a Q2 MOS tube under the action of a U8 chip (TL494) and a peripheral circuit thereof due to a wire feeding given signal. The on-off time of the Q2 MOS tube is controlled, so that the rotating speed of a wire feeding motor is controlled, and a welding wire is driven to feed. Thereafter, the arc is ignited and the welding process begins. In the welding process, the width of the PWM control pulse is mainly determined by a given wire feeding speed value, the pulse width can be changed by changing the given size of the wire feeding, and finally, the size of the wire feeding speed is changed, namely the size of the welding current is actually changed. When a welding gun switch is loosened, the contact of the relay RLY1 is connected with the resistor R16, so that the energy stored on the motor winding is quickly released through R16, and the energy consumption braking control is carried out on the wire feeding motor, so that the wire feeding motor is quickly stopped from rotating, and the wire feeding is stopped. Therefore, the welding wire does not extend out of the gas protection cover at the head of the welding gun too much, and the normal operation of welding is not influenced. Meanwhile, the electromagnetic gas valve is closed in a lagging mode, and the shielding gas achieves lagging gas closing control.
When the gas shielded welding and 4T welding gun operation modes are selected, when a welding gun switch is closed, on one hand, the electromagnetic gas valve is enabled to act, and protective gas is conveyed to a welding area for protection, and on the other hand, the on-off time of the Q2 MOS tube is controlled under the action of the U8 chip and the peripheral circuit thereof due to the fact that a wire feeding given signal exists, so that the rotating speed of a wire feeding motor is controlled, and a welding wire is driven to be fed. Thereafter, the arc is ignited and the welding process begins. When the welding gun switch is released, the U2 control system still enables the electromagnetic gas valve to keep acting, and protective gas is continuously supplied to the welding area. At the same time, there is still a wire feed given signal and the wire feed is maintained under its control. The welding process will still be performed. During the welding process, the wire feeding speed or the welding current can be changed by changing the given size of the wire feeding. When the welding gun switch is closed again, the gas and wire feeding and welding processes continue to be maintained. When the gun switch is released again, the U2 control system outputs a signal to stop feeding wire. Meanwhile, the energy consumption braking control is carried out on the welding wire motor. And the electromagnetic air valve is also closed in a lagging way, so that the lagging air closing control is realized. Eventually, the delivery of shielding gas is stopped. The welding process is ended.
In summary, the PWM signal output from U13 in fig. 7 is a signal for determining the magnitude of the output voltage and current of the inverter main circuit of the welding machine. Its pulse width depends on: 1) when manual welding is carried out, the set signals of welding current and thrust current and the feedback signal of output current are jointly determined. The object or target of control is the output current magnitude. When the device is in idle load, the VRD function is realized; once the arc is ignited, control of manual welding is entered. The PWM pulse signal generated by the control circuit makes two groups of IGBTs in the main inverter circuit in an alternate conduction state, and finally makes the main inverter circuit output current and voltage. When the operator adjusts the set current and performs welding, the control circuit senses an output current feedback signal through the shunt. After circuit processing, on one hand, welding parameter signals displayed by the welding machine can be obtained, parameter display is achieved, on the other hand, current feedback signals are compared with welding current given signals, compared difference signals are subjected to current PI (proportion + integration) negative feedback formed by a rear-stage operational amplifier, and output results U13-2 signals control pulse width or duty ratio output by a PWM chip U13, so that the sizes of output current and voltage of the welding machine are determined, and accurate control of output parameters is achieved. And the output characteristic of the welding machine is the descending characteristic of the constant current band out-of-band dragging. Further, when the welding current setting signal is unchanged, the difference between the welding current setting signal and the current negative feedback control signal is reduced along with the increase of the current after the detected current feedback signal is increased and the current setting value is reached, and the output voltage of the welding machine is reduced by controlling to reduce the output PWM pulse width or the duty ratio. This process is called current cut-off negative feedback control. I.e. a feedback control that is active only when the current reaches the set value of the welding current. Thereafter, as the current increases slightly, the voltage decreases much. When the voltage is reduced to be less than 16V, the control circuit can increase the pulse width or the duty ratio output by the PWM chip along with the reduction of the voltage, so that the welding current is increased according to the set parameters, namely, the control of the thrust current is carried out, and finally the falling characteristic of constant current out-of-band dragging is formed. The current cutoff negative feedback set point is different when the welding current set signal changes, but the other control processes are similar. In this way, between the minimum and maximum current settings, numerous droop characteristics can be obtained. Such control is also a basic requirement for satisfying manual arc welding. 2) The argon arc welding control process is basically similar to that of manual welding, only the control of a thrust current stage is not carried out, and the obtained external characteristic is a vertical descent characteristic; 3) and when the gas shielded welding is in a control state, the welding voltage given signal, the output voltage feedback signal and the current feedback signal are jointly determined. The object or target of control is the output voltage magnitude. When the device is unloaded, the VRD function is still available. After loading, the control is different from that of manual welding. In gas shielded welding, the output characteristic of the welding machine is controlled to be flat rather than the falling characteristic of constant current band out dragging. The method is characterized in that: the load current changes greatly, and the output voltage changes little, and remains relatively stable. Only when the voltage given signal changes does the output voltage change significantly. Current degeneration is to limit excessive current output. Gas shield welding, of course, is much more complex than manual welding, involving control of gas feed, wire feed speed, 2T and 4T modes of operation, and the like. Changing the given value of inductance (different resistances between L1 and L2) the rate of change of welder output current will change, which will change the characteristics of the welding arc. The above control process is realized by a corresponding control circuit.
The above is a brief description of the control process of each circuit board portion and three soldering methods of the present invention. The circuit principle is complicated. The above only gives an idea and result of the control. However, since the present invention has been given a detailed schematic of the circuit, it is fully readable by those with circuit reading capability (or knowledge of the circuit). As can be seen from the above description, the welder structure and control circuit designed by the present invention have its own unique features. The present patent application claims protection of the structure and circuitry of such a welder.
If the components on each circuit board of the welding machine are plug-in electronic components or parts, the circuit board processing is completed mainly by automatic and manual plug-in and automatic welding. And for a large number of surface mount electronic components on each circuit board, all automatic surface mount and welding modes are adopted to finish processing. Trying to think, if all components and parts are not in a surface mount type, the size of the circuit board is inevitably large, which increases the size and weight of the welding machine; if there are many control connection lines between the circuit boards, the manufacturing process is inevitably many and the manufacturing process is also complicated. The present invention takes the above mentioned influencing factors into full consideration. Through repeated design, the circuit board has small size, compact structure and few connection control lines, so the circuit board of the welding machine has few production and processing procedures, greatly simplified manufacturing process and more convenient production. The design and the processing technology can ensure that the production of the product has high production efficiency, and meanwhile, the error rate and the manufacturing cost are low, thereby being beneficial to improving the market competitiveness of the product.
The foregoing is a detailed description of the utility model in conjunction with specific welder structures and circuit boards and control functions and is not intended to limit the practice of the utility model to these descriptions. Numerous other deductions and alterations may be made by those skilled in the art without departing from the spirit of the utility model, which should be considered as falling within the scope of the utility model.
Claims (5)
1. The utility model provides a multi-functional welding machine of single-phase multi-voltage liquid crystal display single encoder accent parameter which characterized in that: the power supply of the welding machine is single-phase 110-120V or 220-240V, and the wire feeding part of the welding machine comprises a welding wire reel shaft, a wire feeding mechanism, an European gas shielded welding gun interface and a wire feeding control circuit part on a main control circuit board; the wire feeding mechanism adopts a support frame of the wire feeding mechanism, a plastic base plate of the wire feeding mechanism, a fixed support I of the wire feeding mechanism and a fixed support II of the wire feeding mechanism to be insulated, isolated and fixedly installed with the vertical middle partition plate and the bottom plate; the wire feeding disc shaft is arranged on the internal vertical middle partition plate; the wire feeding mechanism is close to the front panel of the welding machine and correspondingly connected with an European style gas shielded welding gun interface arranged on the front panel; when gas shield welding is carried out, the gas shield welding gun is matched and connected with the interface of the European gas shield welding gun; the welding wire is installed on the welding wire reel shaft, and the welding wire can be sent to the wire feeding mechanism after being installed and then is conveyed to the head of the welding gun connected with the welding wire through the European gas shielded welding gun interface; a protective gas interface on the welding gun interface of the European gas shield welding is connected to the electromagnetic gas valve through a gas pipe; protective gas is connected to a gas input port of the electromagnetic gas valve from the outside of the welding machine; the shell part of the welding machine comprises a handle, a shell, a door catch, a side cover plate, a bottom plate, a front plastic panel and a rear plastic panel; the parts installed on the plastic panel behind the welding machine mainly include a power switch, an input voltage change-over switch, a power supply line and a plug thereof, a fixed line of the power line, a cooling fan of the rear panel and a fixed bracket thereof, an air connector or an air inlet nozzle of protective air and an electromagnetic air valve part; the fixing bracket of the cooling fan can be fixed on the bottom plate of the shell through screws, and the cooling fan is fixed on the fixing bracket through screws; the parts installed on the plastic panel in front of the welding machine comprise a fixed seat of an European welding gun interface, the European welding gun interface, a black negative polarity output quick connector seat assembly, a red positive polarity output quick connector seat assembly, a welding gun polarity conversion plug and a welding cable connected with the welding gun polarity conversion plug, a wire-drawing SPOOL welding gun connecting wire socket, a liquid crystal display and operation control panel, a front panel metal platelet and a protection box of a front control panel; in the interior of the welding machine, except for parts installed on the front panel and the rear panel, the vertical middle partition plate is fixed on the bottom plate through screws; the EMI filtering plate is arranged on the vertical middle partition plate through screws; the main control board is also arranged on the vertical middle partition board through screws; the main circuit and the power supply circuit board comprise small control boards which are arranged on the circuit board and are fixed on the bottom board as an assembly through supporting pieces and screws, one side of each component is arranged towards the vertical middle partition board, a protective polyester film is fixed on the welding surface of the circuit board, and the protective polyester film is used for protecting the circuit board; the control circuit board part is designed into five blocks which are respectively an EMI input filter circuit board, a main circuit and a power circuit board, a liquid crystal display and operation control circuit board, an electromagnetic valve control and current feedback signal amplification, conversion processing control board or small control board and the main control circuit board, wherein the circuits of the main circuit and the power circuit board part comprise an inverter main circuit, a high-voltage side driving circuit of IGBT and a switch power circuit, and the main circuit comprises an input EMI filter circuit, an upper electricity buffer circuit, a voltage doubling conversion circuit and a control circuit thereof, a half-bridge inverter circuit, a direct current bus current detection and signal conversion processing circuit in a primary circuit of the inverter transformer, an output filter and overvoltage protection circuit, a VRD output control circuit, an absorption protection circuit of IGBT and an absorption protection circuit of a fast recovery diode; the circuit part of the small control panel comprises an electromagnetic air valve control circuit and an amplifying and converting processing circuit for outputting current signals; the main control circuit part comprises an overcurrent and overheat protection control circuit, a low-voltage side drive circuit of an IGBT, a PWM control circuit, a voltage doubling control circuit, an electromagnetic gas valve control circuit, a SPOOL wire drawing gun conversion signal control circuit, an input voltage conversion switch signal control circuit, a welding gun switching signal detection control circuit, a U2 microprocessor and a signal detection and processing control circuit thereof, a wire feeding voltage and current feedback control circuit, a PWM wire feeding control circuit and a wire feeding stopping brake or energy consumption brake control circuit; a signal sampling and processing control circuit of output voltage, a current negative feedback and PI operation control circuit of manual welding and argon arc welding, a voltage negative feedback and PI operation control circuit of gas shielded welding and an arc-withdrawing control circuit of gas shielded welding; the input power supply is connected to the power input end of the welding machine, and the protective grounding of the power supply system is connected with a metal frame or a shell of the welding machine; the back panel of the welding machine is provided with a power switch, and is also provided with a selective change-over switch of power supply voltage, the power supply is connected to the main circuit and the power circuit board at the back stage of the power switch and in the welding machine near the power supply input, the output positive polarity and the negative polarity of the circuit board are respectively and correspondingly connected to the wiring ends of the output positive polarity and negative polarity quick connector components arranged on the front panel of the welding machine, the welding current conducting wiring end of the gas shielded welding European connector component arranged on the front panel of the welding machine is connected with the polarity change quick plug arranged on the front panel of the welding machine through the welding cable in the welding machine, and the polarity change quick plug can be respectively connected with the socket of the output positive polarity and negative polarity quick connector components arranged on the front panel so as to realize that the conducting nozzle of the gas shielded welding gun can be connected with the output positive polarity, the purpose of outputting the conversion of the negative polarity can be connected, argon arc welding or manual welding is adopted, the polarity conversion quick plug is not connected with the output positive and negative polarity sockets outside the welding machine, and two socket interfaces, namely CN5 and CN15, are arranged on a main circuit and a power circuit board of the cooling fan of the welding machine and can be used for connecting the cooling fan; the CN4 socket of the main circuit and the power circuit board is connected with the CN1 socket of the electromagnetic valve control and current feedback signal amplification and conversion processing control panel or the small control panel through a plug and a connecting wire thereof, and the GAS socket of the latter is connected with the electromagnetic air valve in the welding machine through the plug and the connecting wire thereof; the small control board is arranged on the main circuit and the power circuit board; the CN1, CN3, CN6 and CN16 sockets of the main circuit and the power circuit board are respectively connected with the CN1, CN7, CN2 and CN9 sockets of the main control circuit board through plugs and connecting wires thereof; the CN4 socket of the main control circuit board is connected with the CN1 socket of the liquid crystal display and operation control circuit board through a plug and a connecting wire thereof; the MOTO socket of the main control circuit board is connected with a control line of the wire feeding motor through a plug and a connecting wire thereof; the GUN Switch socket of the main control circuit board is connected with a welding GUN Switch control line of an European type welding GUN interface on the front panel of the welding machine through a plug and a connecting line thereof; an OH socket of the main control circuit board is connected with a connecting wire of the overheating protection temperature controller WKQ through a plug and a connecting wire thereof, and the overheating protection temperature controller WKQ is installed in a manner of clinging to the surface of the radiator of the IGBT; welding by using an SPOOL wire-drawing gas shield welding gun, wherein a plug of the SPOOL wire-drawing welding gun is connected with a socket of the wire-drawing welding gun arranged above and below a front panel of the welding machine; switching by adopting an MIG/SPOOL welding gun access change-over switch on a vertical middle partition plate, wherein an MIG/SPOOL socket of a main control circuit board is connected with the MIG/SPOOL welding gun access change-over switch on the vertical middle partition plate of the welding machine through a plug and a connecting wire thereof; the MIG/SPOOL welding gun is connected to a change-over switch, a switching control signal line for the middle U2 and a control line for switching the armature of the wire feeder are provided, and when an European welding gun is used, the change-over switch is arranged on one side of the European welding gun and is simultaneously communicated with the armature control end of the wire feeder; when the wire drawing gun is used, the armature control wire can be communicated to the armature control wire of the wire drawing gun corresponding to the socket below the front panel of the welding machine; the control lines of the wire-drawing gas shielded welding gun socket on the front panel are respectively connected to the voltage output line of the motor armature on the main control panel and two ends of the welding gun switch control line, and the switch of the wire-drawing gun is adopted for welding control operation during welding; the 120V/240V socket of the main control circuit board is connected with the 110-through 120V and 220-through 240V power supply change-over switches on the rear panel of the welding machine through the plug and the connecting wire thereof, and correspondingly inputs the voltage grade signal to the main control circuit board circuit through the change-over of the switches; all circuit boards and peripheral parts thereof are electrically connected; for the part of the control panel for liquid crystal display and operation, a liquid crystal display screen is arranged on the control panel when the welding machine is seen from the outside, and below the liquid crystal display screen, the following parts are arranged: a gas shielded welding/argon arc welding/manual welding method selection key, wherein the gas shielded welding/argon arc welding/manual welding method selection key is used for selecting three corresponding welding methods, and the selected state is indicated on the liquid crystal screen through corresponding welding method symbols; a 2T/4T gas shield welding torch switch operation mode selection key, which is used for selecting the 2T or 4T operation mode of the gas shield welding torch switch and indicating the selected state on the liquid crystal screen through a corresponding symbol; a 'wire detection' or 'wire test feeding'/'gas detection' or 'gas test feeding' selection key, when selecting operation, the selected state can be indicated on the liquid crystal screen through corresponding wire detection, wire test feeding/gas detection or gas test feeding symbols; on the right side of the liquid crystal display screen, are provided with: a parameter option button for selecting corresponding adjustable welding parameters under each of the above welding methods; a parameter adjustment encoder for adjusting the welding parameters selected by the user for each of the welding methods described above.
2. The single phase multiple voltage liquid crystal display single encoder parameter setting multifunctional welder of claim 1, characterized by: the liquid crystal display and operation control circuit board part is connected with a CN4 plug of the welding machine main control board circuit part through a CN1 plug; the circuit of the part consists of a U1 microprocessor, a liquid crystal screen YJ1, a gas detection and wire detection key K3, a gas shielded welding/argon arc welding/manual welding three-welding-method selection key K1, a 2T/4T welding gun switch operation mode selection key K2, a parameter option key K4, a parameter adjusting encoder BMQ, a control panel connection interface CN1, a program programming interface J2, NPN type triodes Q1-Q4, an inductance parameter adjusting control circuit, resistors R1-R12, R21-R36, capacitors C1-C2, C5-C8 and electrolytic capacitors E1-E2; pin 39 of U1 is grounded; pin 38 of U1 is connected with + 5V; decoupling capacitors C1-C2 and filter electrolytic capacitors E1-E2 are connected between +5V and ground; +5V comes from the main control panel section through CN1 interface; the RXD0 terminal of U1 is connected with R21, the other end of R21 is connected with the RXD1 terminal and C5 of a CN1 socket, and the other end of C5 is grounded; the terminal TXD0 of the U1 is connected with the terminal R22, the other terminal of the terminal R22 is connected with the terminal TXD1 and the terminal C6 of the socket CN1, and the other terminal of the terminal C6 is grounded; by using the plug and the control line thereof, the two terminals are in serial port communication with the U2 microprocessor on the main control board part of the welding machine, so that the real-time exchange of data between the liquid crystal display and operation control circuit and the main control circuit of the welding machine can be realized; the 42-pin KEY1 wiring end of U1 is connected with R23 and R24 which are connected in series between the ground, the middle connecting point of R23 and R24 is connected with 1 pin and 4 pins of a KEY K1, and 2 pins and 3 pins of K1 are connected with + 5V; the 35-pin KEY2 wiring end of U1 is connected with R25 and R26 which are connected in series between the ground, the middle connecting point of R25 and R26 is connected with 1 pin and 4 pins of a KEY K2, and 2 pins and 3 pins of K2 are connected with + 5V; the 34-pin KEY3 wiring end of U1 is connected with R27 and R28 which are connected in series between the ground, the middle connecting point of R27 and R28 is connected with 1 pin and 4 pins of a KEY K3, and 2 pins and 3 pins of K3 are connected with + 5V; the 31-pin KEY4 wiring end of U1 is connected with R29 and R30 which are connected in series between the end to the ground, the middle connecting point of R29 and R30 is connected with 1 pin and 4 pins of a KEY K4, and 2 pins and 3 pins of K4 are connected with + 5V; one large pin of R1 is connected with pin A2 of U1, the other end of R1 is connected with the bases of triodes of R2 and Q1, the emitter of Q1 is grounded, the collector of Q1 is connected with A1 and R3, the other end of R2 is grounded, and the other end of R3 is connected with + 5V; one large end of R4 is connected with a pin B2 of U1, the other end of R4 is connected with bases of triodes of R5 and Q2, an emitter of Q2 is grounded, a collector of Q2 is connected with B1 and R6, the other end of R5 is grounded, and the other end of R6 is connected with + 5V; one large end of R7 is connected with a pin C2 of U1, the other end of R7 is connected with bases of triodes of R8 and Q3, an emitter of Q3 is grounded, a collector of Q3 is connected with C1 and R9, the other end of R8 is grounded, and the other end of R9 is connected with + 5V; one large of R10 is connected with a 32-pin BGD2 of U1, the other end of R10 is connected with bases of triodes of R11 and Q4, an emitter of Q4 is grounded, a collector of Q4 is connected with R12, the other end of R11 is grounded, and the other end of R12 is connected with a 22-pin BGD1 of a YJ1 liquid crystal screen; the 1 pin of the digital encoder BMQ for parameter adjustment is connected with R33, R34 and a decoupling capacitor C7, the other end of R33 is connected with +5V, the other end of R34 is connected with a 4 pin PULSE of U1, and the other end of C7 is grounded; the 2 pin of the BMQ is grounded; the 3-pin of the BMQ is connected with R36, R35 and a decoupling capacitor C8, the other end of R36 is connected with +5V, the other end of R35 is connected with a 5-pin DIR of U1, and the other end of C8 is grounded; pins 1 and 3 of the BMQ are parameter signal output ends of the encoder; the 4 and 5 feet of BMQ are KEY connection ends of encoder, the 4 feet of BMQ are connected with +5V, the 5 feet of BMQ are connected with R31 and R32, the other end of R32 is grounded, the other end of R31 is connected with 30 feet KEY5 of U1, one end of R16 is connected with L1 end of CN1 and number 4 of normally open contact of relay JDQ1, the other end of R16 is connected with number 3 and number R17 of normally open contact of relay JDQ1 and number 4 of normally open contact of relay JDQ2, the other end of R17 is connected with number 3 and number R18 of normally open contact of relay JDQ2 and number 4 of normally open contact of relay JDQ3, the other end of R17 is connected with end L2 of CN1, namely, the contacts of JDQ1, JDQ2 and JDQ3 are respectively connected with R3, R3 and R3 in parallel, the action states of different resistances of L3 and JDQ3 and the other ends of JDQ3 are respectively connected with control coil pack 72 and a control signal wire package 3, and A3 and a control switch 3 and a control coil 3, determining the action of the relay, and finally determining different inductance parameter values; 6-9 pin COM 1-COM 4 ends of the U1 are respectively connected with 1-4 pin COM 1-COM 4 ends of the YJ1 liquid crystal screen; the SEG 6-SEG 21 ends of the 14-29 pins of the U1 are respectively connected with the SEG 6-SEG 21 ends of the 5-20 pins of the YJ1 liquid crystal screen; the 21 pin of the YJ1 LCD screen is connected with +5V, the 22 pin BGD1 of the YJ1 LCD screen is connected with R22 and controlled by the BGD2 control signal end of U1, when the BGD2 end of U1 outputs high level, the triode of Q4 is conducted, the BGD1 is grounded through R12, and the backlight of the LCD screen can be lightened.
3. The single phase multiple voltage liquid crystal display single encoder parameter setting multifunctional welder of claim 1, characterized by: the signal sampling and processing control circuit part of the output voltage comprises a CN9 socket, a U3 operational amplifier, a U5 linear optical coupler, and peripheral resistor and capacitor components thereof; CN9 is connected to two ends of OUTPUT of welder, CN9-1 is connected to OUTPUT (+) positive OUTPUT end of welder; the negative polarity output end of the capacitor is connected with CN9-2 and is grounded; CN9-1 is connected with R8; the other end of the R8 is connected with the R7, and the end is connected with the ground in parallel with R10 and C13; the other end of R7 is connected with the non-inverting input end of U3, the inverting input end of U3 is connected with the emitter or 4 pin of the triode in C11, R18 and U5, the other end of R18 is grounded, the other end of C11 is connected with the output end of U3, the output end is connected with R9, the other end of R9 is connected with the anode or 2 pin of the LED of U5, the 1 pin of U5 or the cathode of the LED is grounded, and the 3 pin of U5 or the collector of the internal triode is connected with + 15V; the power supply of U3 is +15V and ground; r8 and R10 form a voltage divider circuit, so that the voltage obtained by the later stage is reduced; u5 is a linear optocoupler, the collector or 6 pins of a triode at the output side of U5 is connected with +15V, and a C6 filter capacitor and a C7 filter capacitor are connected between the power supply and the ground in parallel; an emitter or a 5 pin of an output side triode of the U5 is connected with a pin 10 of a non-inverting input end of the C16, the R17 and the U101C operational amplifier, the other end of the C16 is grounded, the other end of the R17 is connected with a pin 3 of the variable potentiometer RP2, and a middle sliding point and a pin 1 of the RP2 are grounded; the pin 9 of the inverting input end of the U101C is connected with the pin 8 of the output end thereof, the output end is connected with the R12, the other end of the R12 is connected with the cathode of the ZD2 voltage regulator tube and the pin 12 of the non-inverting input end of the U101D operational amplifier; ZD2 anode ground, U101D inverting input 13 pin connected its output 14 pin, the output connected R15, R15 other end connected RP 13 pin, RP1 middle sliding point 2 pin and 1 pin connected, and also connected R14, U101A operational amplifier non-inverting input 3 pin; the working power supply of the U101 operational amplifier is +15V and-15V; in a pin 3 of a non-inverting input end of the U101A operational amplifier, one input resistor is R14, and the other input resistor is an RP1 variable resistor and R15; the signal connected to the input end of the R15 is an output voltage sampling signal from an output voltage sampling circuit and passing through a voltage division circuit and a U101C and U101D two-stage operational amplifier processing circuit; the signal inputted through the R14 resistor is a welding output voltage setting signal at the time of gas shield welding.
4. The single phase multiple voltage liquid crystal display single encoder parameter setting multifunctional welder of claim 1, characterized by: the voltage negative feedback and PI operation control circuit part of gas shielded welding comprises a circuit consisting of a U101A operational amplifier and peripheral components thereof; two amplitude limiting diodes D12 and D13 in opposite directions are connected in parallel between the non-inverting input end and the inverting input end of the U101A operational amplifier, and the non-inverting input end of the U101A operational amplifier is connected with an input resistor R14 and a branch thereof, and an input resistor RP1 variable resistor, an input resistor R15 and a branch thereof; the inverting input end of the U101A is connected with the cathodes of the R39 and D15 diodes, and the anode of the D15 is connected with the pin 14 of the output end of the U103D operational amplifier; a network consisting of a resistor, a capacitor and a voltage regulator tube is connected between the inverting input end of the U101A operational amplifier and the output end pin 1; the structure of the network is that C24, R37 and ZD4 voltage-stabilizing tubes are connected in parallel, one end of the anode of ZD4 in the parallel device is connected with the pin 1 at the output end of U101A, the other end of the parallel device is connected with R38, and the other end of R38 is connected with the inverting input end of U101A operational amplifier; the network of the U101A operational amplifier part is a PI control operation circuit, and is also a PI operation control circuit of MIG/MAG gas shielded welding; in a pin 3 of a non-inverting input end of the U101A operational amplifier, one input resistor is R14, and the other input resistor is an RP1 variable resistor and R15; the signal connected to the input end of R15, the signal input through the R14 resistor is the welding output voltage given signal during gas shielded welding; the output of U101A is connected with R24 and R28, the other end of R24 is connected with R26 and L1, the other end of R26 is connected with L2, the cathode of D14 diode, the emitter of output stage triode of U6 optical coupler, and the 5 pins of non-inverting input end of R55 and U101B operational amplifier; the other end of the R28 is connected with the anode of the D14 and the collector of an output triode of the U6 optocoupler; the connection between the terminals L1 and L2 is in a loop for changing the welding parameters of the inductance of the welding machine, and a variable resistor is connected between the terminals L1 and L2; the non-inverting input terminal of the U101B is connected in parallel with diodes C25, R48 and D16 between the non-inverting input terminal of the U101B and the ground, the cathode of the D16 is grounded, the pin 6 of the inverting input terminal of the U101B is connected with the pin 7 of the output terminal of the U101B, the pin 7 of the output terminal is connected with R60, the other end of the R60 is connected with the anodes of the diodes R63, R71 and D19, the inverting input terminals of the diodes R69 and U102B, the non-inverting input terminal of the U102B is grounded, and a network consisting of a resistor, a capacitor and a diode is also connected between the inverting input terminal of the U102B operational amplifier and the pin 7 of the output terminal of the U102 operational amplifier; the structure of the network is C39 and R77 which are connected in parallel, one end of the parallel device is connected with the output end 1 pin of U102B, the other end of the parallel device is connected with R69, the other end of R69 is connected with the inverting input end of U102B operational amplifier, the cathode of a D19 diode is connected with the output end 1 pin of U102B, and the anode of the D19 diode is connected with the inverting input ends of R60, R71 and U102B operational amplifier; the pin 1 of the output end of the U102B is connected with R85, and the other end of R85 is connected with the contact 10 point of the RLY2 relay; the circuit formed by the U102B and the network thereof is a PI control circuit; during gas shielded welding, the 5 and 6 points of the RLY2 relay contact are connected with the 10 points of the contact, and the signal from the R85 is the input signal of U16B; during gas shielded welding, the output current feedback signal of the welding machine is still input to a PI control operation link formed by U16D through R164 to limit the output current of the welding machine.
5. The single phase multiple voltage liquid crystal display single encoder parameter setting multifunctional welder of claim 1, characterized by: the current negative feedback and PI operation control circuit part of the manual welding and argon arc welding comprises a U103A operational amplifier; the power supply of U103 is + 15V-15V; the feedback signal of the output current of the welding machine is an IFB or ADCI2 current feedback signal which comes from a small control board of the welding machine; the working power supply of the U103 operational amplifier is + 15V-15V; the IFB or ADCI2 current feedback signal is connected to the non-inverting input end of the U013A operational amplifier through R3, and the inverting input end of the U013A is connected with the output end; the output end signal of U013A is the output current feedback signal of the welder, and is also the signal participating in the current negative feedback and PI operation control; the circuit is connected with R61 and R164, R61 is an input resistor of U103B, the circuit is connected with the inverting input end of U103B, the other input resistor of U103B is R63, and the circuit is connected with the inverting input ends of R60, R71 and U102B operational amplifiers; r164 is an input resistor of the U16D operational amplifier and is connected with the inverting input end of the U16D, the other two input resistors of the U16D are R161 and R160, the other end of the R161 is connected with +15V, and the input of the R160 is the output of the synchronous follower U16C; the non-inverting input end of the U16D is connected with the ground through R162, and a network consisting of a resistor and a capacitor is also connected between the inverting input end of the U16D operational amplifier and the output end 14 pin of the U16D operational amplifier; the structure of the network is that C93 and R165 are connected in parallel, one end of the parallel device is connected with a pin 14 of an output end of U16D, the other end of the parallel device is connected with R163, the other end of the R163 is connected with an inverting input end of U16D, and the operational amplifier circuit of the part is a PI operation circuit; the pin 14 of the output end of the U16D is connected with R166, the other end of the R166 is connected with R167 and R169, the other end of the R169 is grounded, the other end of the R167 is connected with the pin 2 of the U13 PWM chip, and the output signal end also controls the pulse width of the output PWM signal of U13; the change in the output control signal of R167 determines the pulse width of the PWM signal output from U13.
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| CN115319226A (en) * | 2022-08-04 | 2022-11-11 | 吴忠市黄河电焊机有限公司 | Voltage stabilizing system and digital gas shielded welding machine with same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115319226A (en) * | 2022-08-04 | 2022-11-11 | 吴忠市黄河电焊机有限公司 | Voltage stabilizing system and digital gas shielded welding machine with same |
| CN115319226B (en) * | 2022-08-04 | 2024-04-05 | 吴忠市黄河电焊机有限公司 | Voltage stabilizing system and digital gas shielded welding machine with same |
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Assignee: Zhejiang Kende Cleaning Equipment Co.,Ltd. Assignor: ZHEJIANG KENDE MECHANICAL & ELECTRICAL Co.,Ltd. Contract record no.: X2024330000323 Denomination of utility model: Multi functional welding machine with single-phase multi voltage LCD display and single encoder parameter adjustment Granted publication date: 20220405 License type: Common License Record date: 20240801 |