High-efficiency energy-saving TIG welding power supply system for field operation

Abstract

The application provides a high-efficiency energy-saving TIG welding power supply system for field operation, and belongs to the technical field of welding. The system comprises a PFC+DC / DC circuit, a super capacitor, a full-bridge inverter circuit, a current detection circuit, a voltage detection circuit and an interactive interface. The system adopts a high-density super capacitor group energy storage module to provide energy for GTAW, and realizes GTAW welding in a field environment without electricity or a small space with difficult power supply. The system adopts a SiC mosfet full-bridge topology to regulate current, and a PFC power factor correction circuit to suppress current pulse amplitude. The system realizes energy saving in the switching process through a new SiC mosfet and a SiC power diode, and reduces energy loss in the switching process of the switching tube.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, specifically relating to a high-efficiency and energy-saving TIG welding power supply system for field operations. Background Technology

[0002] Power supply for high-power welding equipment during field operations poses a challenge, making the development of new energy-efficient welding power supplies suitable for such operations a new technological bottleneck. Furthermore, welding inside the nuclear island, where space is limited, still presents power supply issues. This patent proposes a TIG power supply with supercapacitor energy storage to address these challenges in providing welding power. Summary of the Invention

[0003] Purpose of the invention: To address the aforementioned existing technologies, a high-efficiency and energy-saving TIG welding power supply system for field operations is proposed.

[0004] Technical solution:

[0005] A high-efficiency, energy-saving TIG welding power supply system for field operations, including a PFC+DC / DC circuit, a supercapacitor, a full-bridge inverter circuit, a current detection circuit, a voltage detection circuit, and an interactive interface.

[0006] The PFC+DC / DC circuit includes SiC MOSFETs Q1-Q6, a primary-side full-bridge circuit Q7-Q10, resonant inductors L3-L6, resonant capacitors C2 and C3, and a secondary-side rectifier circuit Q11-Q14. The input terminal of SiC MOSFET Q1 is the three-phase power filtered by L1-L2, the input terminal of SiC MOSFET Q7 is the VDC with power factor corrected by the PFC circuit, the input terminal of resonant inductor L3 is the VDC output from the primary-side full-bridge circuit, and the input terminal of SiC MOSFET Q11 is the VDC resonated by L3-L6.

[0007] The full-bridge inverter circuit includes SiC MOSFETs Q15-Q18; the input terminal of SiC MOSFET Q15 is the VDC output from supercapacitors C5-Cn+1.

[0008] The current detection circuit includes a first MCU controller, a Hall effect sensor, and a first OPA320 operational amplifier; the input terminal of the first MCU controller is the amplified signal output by the first OPA320 operational amplifier, and the input terminal of the Hall effect sensor is I... inv The input terminal of the first OPA320 operational amplifier is the current signal detected by the Hall effect sensor;

[0009] The voltage detection circuit includes a second MCU controller, an AMC1301 isolation amplifier, and a second OPA320 operational amplifier; the input terminal of the second MCU controller is a voltage sensor, the input terminal of the AMC1301 isolation amplifier is the bus voltage, and the input terminal of the second OPA320 operational amplifier is the anti-electromagnetic interference voltage output by the isolation amplifier.

[0010] The interactive interface includes an initial parameter setting interface, a welding power supply energy storage interface, and a welding power supply welding interface; the initial parameter setting interface is used to set initial parameters, the welding power supply energy storage interface is used to manage and monitor the welding power supply energy storage process, and the welding power supply welding interface is used to set welding parameters, set communication parameters, and manage the welding process.

[0011] The interactive interface is communicatively connected to the first MCU controller and the second MCU controller, and the first MCU controller and the second MCU controller are connected to the PFC+DC / DC circuit, the current detection circuit and the voltage detection circuit;

[0012] The output terminal of the PFC+DC / DC converter is a supercapacitor, and the output terminal of the full-bridge inverter circuit is connected to the welding workpiece and the tungsten electrode.

[0013] Preferably, the welding power supply system further includes a power transistor drive circuit, which includes an NSI6602B-DSWR driver board and a SiC MOSFET power transistor. The INA and INV pins of the NSI6602B-DSWR driver board are connected to PWM signals Vg1 and Vg2, respectively. The ADDI, GNDI, and VDDI pins of the NSI6602B-DSWR driver board are connected to 5Vp, PGND, and 5Vp, respectively. The VDDA, OUTA, and GNDA pins of the NSI6602B-DSWR driver board are connected to +15Va, G1, and -4Va, respectively.

[0014] The VDDB, OUTB, and GNDB pins of the NSI6602B-DSWR driver board are connected to +15Vb, G2, and -4Vb, respectively.

[0015] Preferably, the power supply system further includes a driver chip, a voltage regulator capacitor S_C9-11, and a filter capacitor S_C1-4. The +V0, 0V, and -V0 pins of the driver chip are connected to +15Va, Conna, and -4Va, respectively, and the GND and VIN pins of the driver chip are connected to PGND and 15Vp, respectively.

[0016] Beneficial effects:

[0017] 1. High-density supercapacitor energy storage modules are used to provide energy for TIG welding, enabling TIG welding in outdoor environments without electricity or in confined spaces where power supply is difficult.

[0018] 2. The front end adopts a PFC power factor correction circuit, which improves the power factor of the charging circuit through active power correction. The PFC is connected to the power grid to perform AC / DC power conversion, reduce harmonic current, and obtain the open-circuit voltage required by the supercapacitor energy storage module through a DC-DC converter.

[0019] 3. The direct current generated by solar photovoltaic power can be connected to a power source to power the batteries and provide energy for welding. The direct current generated by photovoltaic power does not need to be connected to the grid and directly powers the equipment.

[0020] 4. High-density supercapacitors are used for continuous power supply to provide energy for welding full-bridge inverters; energy saving is achieved in the power supply process by controlling the energy output rate. The MCU controller collects the voltage and current values ​​of the supercapacitors and sends and receives commands through CAN communication to realize energy output control.

[0021] 5. The current is regulated by using a SiC MOSFET full-bridge topology, and the current pulse amplitude is suppressed by a PFC power factor correction circuit; energy saving in the switching process is achieved by using a new type of SiC MOSFET and SiC power diode, reducing energy loss during the switching process of the switching transistor. Attached Figure Description

[0022] Figure 1 This is a structural diagram of a high-efficiency and energy-saving TIG welding power supply system for field operations;

[0023] Figure 2 This is a power supply topology diagram;

[0024] Figure 3 It is a power transistor drive circuit;

[0025] Figure 4 It is the power supply for the driver chip;

[0026] Figure 5 This is the software workflow for TIG welding power sources in field operations;

[0027] Figure 6 It is the energy storage interface for welding power supplies;

[0028] Figure 7 It is the welding interface of the welding power source;

[0029] Figure 8 This is a table showing how battery voltage changes over time. Detailed Implementation

[0030] The invention will now be further explained with reference to the accompanying drawings.

[0031] 1. System Structure

[0032] The structure of a high-efficiency, energy-saving TIG welding power supply system for field operations, such as... Figure 1 As shown, the system consists of a PFC+DC / DC converter, a supercapacitor, a full-bridge inverter circuit, a current detection circuit, a voltage detection circuit, and an interactive interface. The interactive interface is used to monitor three-phase voltage and current in real time, display the system's operating status, and set parameters such as output voltage and current. The controller is connected to the interactive interface using an MCU controller USB cable. The MCU controller's isolated CAN port receives the voltage and current parameters set in the interactive interface and operates according to the program settings. The MCU controller controls the PFC and DC-DC inverter to obtain the voltage values ​​required for the supercapacitor and welding, or directly connects the DC / DC module to power the supercapacitor and welding via solar photovoltaic power generation. Simultaneously, the MCU collects the supercapacitor's voltage and current values ​​and sends and receives commands via CAN communication to achieve digital power control, meeting the needs of TIG welding in the field. The power supply is a 380V AC input at industrial frequency. The PFC+DC / DC converter connects to the power grid and the high-density supercapacitor. The PFC connects to the power grid for AC / DC power conversion, reducing harmonic currents, and obtains the open-circuit voltage required for the supercapacitor and welding through the DC-DC converter. The supercapacitor stores electrical energy, providing power for the welding full-bridge inverter. Energy saving is achieved by reducing energy loss during the inverter process using SiC MOSFETs.

[0033] 2. Hardware Circuit

[0034] Power supply topology, such as Figure 2As shown. It consists of a power factor correction circuit (Q1-Q6), a CLLC inverter circuit (Q7-Q14), a welding current inverter circuit (Q15-Q18), resonant inductors (L1,L2), resonant inductors (L3,L6), a voltage regulator capacitor (C1), a resonant capacitor (C2,C3), a high-density supercapacitor bank (C4-Cn+1), and a welding workpiece. (1) The three-phase power is filtered by L1-L2 and input to the PFC circuit composed of SiC MOSFET diodes Q1-Q6. It enters the CLLC voltage regulation module through capacitor C1. The primary side full bridge (Q7-Q10) passes through the resonant inductors (L3,L6), the resonant capacitors (C2,C3), and the secondary side rectifier circuit (Q11-Q14) to obtain the voltage and current values ​​required to charge the supercapacitor. In the energy storage mode, it charges the supercapacitor (C5-Cn+1). (2) DC power supply (solar photovoltaic DC) is connected to both ends of capacitor C1. This topology can be input, and the supercapacitor is charged and welded by the CLLC inverter circuit (Q7-Q14); (3) Welding mode: The supercapacitor (C5-Cn+1) serves as the welding energy source. When welding begins, the current flows through the full-bridge circuit (Q15-Q18) to power the workpiece and electrodes, completing the welding. Q15-Q18 obtains the pulse welding current required for welding by adjusting the PWM duty cycle.

[0035] To reduce energy loss in the rectification and inversion process of the power circuit, SiC MOSFETs are used as power transistors, and their drive circuits, such as... Figure 3 As shown, a high-reliability dual-channel isolated gate driver U1 is used. PWM signals Vg1 and Vg2 are input through INA and INV, and output to OUTA and OUTB. Each output can generate a 4A peak current and sink a 6A peak current, outputting two sets of pulses G1 and G2 to the gate of the SiC MOSFET. Because the SiC MOSFET requires a negative voltage to ensure stable turn-off, GNDA and GNDB are connected to -4V respectively. At the same time, DIS is connected to GND to enable U1. The dead time of the INA and INV signals is adjusted through S_R2 and S_C5 to avoid simultaneous turn-on of the upper and lower transistors of the same bridge arm during the upper and lower bridge driving process, thus preventing damage to the switching transistors.

[0036] The power supply circuit for the driver chip, such as Figure 4 As shown, this circuit provides +15V and -4V voltages to the SiC MOSFET. The input voltage regulator consists of capacitors S_C9, S_C10, and S_C11, powered by 15VDC. After filtering, the +15V and -4V voltages are obtained at the output. The +15V filter capacitors consist of capacitors S_C1-S_C4, and the -4V filter capacitors consist of capacitors S_C5-S_C8. This provides a stable drive pulse for driving the SiC MOSFET.

[0037] 3. Control software

[0038] GTAW power supply software workflow for field operations, such as Figure 5 As shown. The software consists of an initialization homepage interface, a menu interface, an energy storage interface, and a welding interface. The system starts running, enters the initialization interface, sets the parameter functions, selects the energy storage mode or the welding mode, and enters the charging state in the energy storage mode, which is divided into AC power supply and DC power supply. (1) The AC power supply obtains stable DC power through PFC+CLLC to charge the supercapacitor module; (2) The DC power supply, such as the DC source of photovoltaic power generation, can be directly connected to the CLLC terminal to modulate the voltage and provide energy for battery charging and welding; (3) In the welding mode, enter the welding interface, set the welding voltage, welding current and switching frequency and start welding. The welding parameters are monitored through CAN communication and the welding ends after the welding is completed.

[0039] Figure 1 This is a structural diagram of a high-efficiency, energy-saving GTAW power supply system for field operations; it includes an interactive interface, an MCU controller, a PFC+DC / DC converter, a supercapacitor, and a full-bridge inverter. The interactive interface is connected to the MCU for communication, the MCU controller is connected to the PFC circuit and the current and voltage detection circuit, the output terminal of the PFC+DC / DC converter is the supercapacitor, the input terminal of the supercapacitor is the PFC+DC / DC converter, and the output terminal of the full-bridge inverter is connected to the welding workpiece and the tungsten electrode.

[0040] Figure 2 This is a power supply topology diagram; it includes a PFC + DC / DC circuit, a supercapacitor, and a full-bridge inverter circuit. The input of the PFC is the three-phase power filtered by L1-L2; the input of the DC / DC circuit is VDC with power factor corrected by the PFC circuit; the input of the supercapacitor is VDC resonant through L3-L6; and the input of the full-bridge inverter circuit is the VDC output from supercapacitors C5-Cn+1.

[0041] Figure 3 This is a power transistor driver circuit, including an NSI6602B-DSWR driver board and a SiC MOSFET power transistor. The INA and INV pins of the NSI6602B-DSWR driver board are connected to PWM signals Vg1 and Vg2, respectively. The ADDI, GNDI, and VDDI pins of the NSI6602B-DSWR driver board are connected to 5Vp, PGND, and 5Vp, respectively. The VDDA, OUTA, and GNDA pins of the NSI6602B-DSWR driver board are connected to +15Va, G1, and -4Va, respectively. The VDDB, OUTB, and GNDB pins of the NSI6602B-DSWR driver board are connected to +15Vb, G2, and -4Vb, respectively.

[0042] Figure 4This is the power supply for the driver chip; it includes the driver chip, voltage regulator capacitors (S_C9-11), and filter capacitors (S_C1-4). The +V0, 0V, and -V0 pins of the driver chip are connected to +15Va, Conna, and -4Va, respectively, and the GND and VIN pins of the driver chip are connected to PGND and 15Vp, respectively.

[0043] Welding power supply energy storage interface, such as Figure 6 As shown. The system consists of a mode switching button, an AC power section on the left, a DC power section on the right, an indicator light at the top right, and a button at the bottom right. The mode switching button comprises menu, energy storage mode, welding mode, and FRA mode. Clicking "Menu" enters the power-on initialization menu interface; clicking "Energy Storage Mode" enters the energy storage interface; clicking "Welding Mode" enters the welding interface; and clicking "FRA Settings" enters the FRA settings interface.

[0044] (1) In the AC power supply section, the upper box displays the input L-NAC voltage value, current value, active power, apparent power, and active energy, while the lower box displays the output voltage value, current value, active power, apparent power, and power factor. Clicking the "Constant Voltage Mode" button will cause the DC power supply to operate in constant voltage mode, and clicking the "Constant Current Mode" button will cause the DC power supply to operate in constant current mode.

[0045] (2) In the DC power supply section, the input and output voltage and current are displayed. Clicking the "Constant Voltage Mode" button will cause the DC power supply to operate in constant voltage mode. Clicking the "Constant Current Mode" button will cause the DC power supply to operate in constant current mode. Clicking the "Start Charging" button will turn on the "Charging" indicator light. Clicking the "Stop Charging" button will turn off the "Charging" indicator light. The power indicator light will show the real-time power level during the charging process. When charging is complete, the "Fully Charged" indicator light will turn on. When a circuit malfunctions and cannot charge normally, the "Fault" indicator light will turn on.

[0046] Welding power source welding interface, such as Figure 7As shown, it consists of a closed-loop real-time parameter display box, a communication setting box, a parameter setting box, indicator lights, and buttons. The power indicator light shows the remaining power during the welding process; when the system is running, the running indicator light illuminates; if a system malfunction occurs, the fault indicator light illuminates; during welding, the welding indicator light illuminates. The closed-loop real-time parameters display the input and output voltage and current values, output apparent power, output active power, output active energy, and power factor. The communication connection box displays the communication connection status between this user software and the MCU control circuit. When communication is successful, the "Connection Successful" checkbox is checked. The software defaults to checking "Save Last Options" to save the welding parameters used in the last use. The parameter setting box is used to set the welding parameters. Based on the thickness of the workpiece, select the welding current, peak current, welding speed, and wire feed speed. After setting the argon flow rate, pulse width, and pulse frequency, welding can begin. Click the "Start Welding" button to start welding, and click the "Stop Welding" button to stop welding.

[0047] The test results of the supercapacitor operating efficiency are shown in Table 1. With an input bus voltage of 349 VAV, a PFC output of 700 VDC is obtained, which is then stepped down by a DC / DC converter to obtain the output voltage. The open-circuit voltage is 91.31 V, the system power is 10.1 kW, and the efficiency is 99.6%. With an open-circuit voltage of 90.95 V, the system power is 18.8 kW, and the efficiency is 99.3%.

[0048] Table 1. Results of Operational Efficiency Test

[0049]

[0050] The voltage of the supercapacitor gradually decreases with welding time, such as... Figure 8 As shown. Welding current of 50A for 8 hours, the power supply voltage drops from 100V to 75V; welding current of 100A for 8 hours, the power supply voltage drops from 100V to 70V; welding current of 200A for 8 hours, the power supply voltage drops from 100V to 65V; welding current of 300A for 8 hours, the power supply voltage drops from 100V to 60V; welding current of 600A for 8 hours, the power supply voltage drops from 100V to 50V.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-efficiency energy-saving TIG welding power supply system for field operation, characterized in that, Includes PFC+DC / DC circuit, supercapacitor, full-bridge inverter circuit, current detection circuit, voltage detection circuit, and user interface: The PFC+DC / DC circuit includes SiC MOSFETs Q1-Q6, a primary-side full-bridge circuit composed of SiC MOSFETs Q7-Q10, resonant inductors L3-L6, resonant capacitors C2 and C3, and a secondary-side rectifier circuit composed of SiC MOSFETs Q11-Q14. The input terminal of SiC MOSFET Q1 is the three-phase power filtered by L1 and L2, the input terminal of SiC MOSFET Q7 is the VDC with power factor corrected by the PFC circuit, the input terminal of the resonant inductor L3 is the VDC output by the primary-side full-bridge circuit, and the input terminal of SiC MOSFET Q11 is the VDC resonated by L3-L6. The full-bridge inverter circuit includes SiC MOSFETs Q15-Q18; the input terminal of SiC MOSFET Q15 is the VDC output from supercapacitors C5-Cn+1. The current detection circuit comprises a first MCU controller, a Hall effect sensor and a first OPA320 operational amplifier; an input end of the Hall effect sensor is used for collecting the inverter current I inv , an input end of the first OPA320 operational amplifier is used for detecting a current signal of the Hall effect sensor, and an input end of the first MCU controller is used for outputting an amplified signal of the first OPA320 operational amplifier; The voltage detection circuit includes a second MCU controller, an AMC1301 isolation amplifier, and a second OPA320 operational amplifier. The input terminal of the AMC1301 isolation amplifier is used to acquire the bus voltage, and its output terminal is connected to the input terminal of the second OPA320 operational amplifier. The output terminal of the second OPA320 operational amplifier is connected to the input terminal of the second MCU controller. The interactive interface includes an initial parameter setting interface, a welding power supply energy storage interface, and a welding power supply welding interface; the initial parameter setting interface is used to set initial parameters, the welding power supply energy storage interface is used to manage and monitor the welding power supply energy storage process, and the welding power supply welding interface is used to set welding parameters, set communication parameters, and manage the welding process. The interactive interface is communicatively connected to the first MCU controller and the second MCU controller. The first MCU controller is connected to the PFC+DC / DC circuit and the current detection circuit, and the second MCU controller is connected to the voltage detection circuit. The output terminal of the PFC+DC / DC circuit is a supercapacitor, and the output terminal of the full-bridge inverter circuit is connected to the welding workpiece and the tungsten electrode.

2. The high-efficiency and energy-saving TIG welding power supply system for field operations as described in claim 1, characterized in that, The welding power supply system also includes a power transistor drive circuit, which includes an NSI660 2B-DSWR driver board and a SiC MOSFET power transistor. The INA and INV pins of the NSI660 2B-DSWR driver board are connected to PWM signals Vg1 and Vg2, respectively. The ADDI, GNDI, and VDDI pins of the NSI660 2B-DSWR driver board are connected to 5Vp, PGND, and 5Vp, respectively. The VDDA, OUTA, and GNDA pins of the NSI660 2B-DSWR driver board are connected to +15Va, G1, and -4Va, respectively. The VDDB, OUTB, and GNDB pins of the NSI660 2B-DSWR driver board are connected to +15Vb, G2, and -4Vb, respectively.

3. The high-efficiency and energy-saving TIG welding power supply system for field operations as described in claim 1, characterized in that, The welding power supply system also includes a driver chip, a voltage regulator capacitor S_C9-11, and a filter capacitor S_C1-4. The +V0, 0V, and -V0 pins of the driver chip are connected to +15Va, Conna, and -4Va, respectively, and the GND and VIN pins of the driver chip are connected to PGND and 15Vp, respectively.

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