Insulated gate bipolar transistor (IGBT) driving circuit for welding wire induction heating power supply

Abstract

The utility model relates to an IGBT (Insulated Gate Bipolar Translator) driving circuit for a welding wire induction heating power supply, which comprises a main driving circuit for realizing optocoupler isolation input, level conversion, driving voltage opening and closing and driving voltage driving output; the first driving voltage control circuit is used for realizing driving voltage control; the second driving voltage control circuit is matched with the first driving voltage control circuit and is used for realizing accurate control and stable output of the driving voltage; and the feedback circuit is matched with the main driving circuit, the first driving voltage control circuit and the second driving voltage control circuit and is used for realizing second-order overcurrent protection. The utility model has the advantages that the adopted isolation optocoupler U1 has large driving current and strong driving capability. Therefore, the driving circuit can stably output driving signals, the IGBT module is effectively driven, it is ensured that the welding wire induction heating power supply can reliably operate under the conditions of high frequency and high power, and the overall performance and stability of equipment are improved.

Description

Technical Field

[0001] This utility model relates to an IGBT drive circuit for a welding wire induction heating power supply, belonging to the field of electromagnetic induction heating power supply. Background Technology

[0002] In actual operation, induction heating power supplies for welding wire typically face high-frequency, high-power operating conditions and require continuous operation for extended periods (24 hours x 7 days), placing extremely high demands on the reliability of the power supply. In induction heating power supplies for welding wire, the drive circuit is the core component for stable operation; its performance and stability directly affect the reliability and safety of the entire power system.

[0003] However, existing drive circuits are mainly designed for general applications, typically suitable for high-power, low-frequency or low-power, high-frequency scenarios, making it difficult to meet the stable operation requirements of welding wire induction heating power supplies under high-frequency, high-power conditions. Furthermore, most existing drive circuits employ a sealed structure, which, while improving circuit protection to some extent, also limits their heat dissipation capacity and adaptability.

[0004] Currently, the drive circuits of induction heating power supplies for welding wire have several problems. First, the applicable frequency band of existing drive circuits does not match the actual needs of induction heating power supplies for welding wire, resulting in the inability to effectively guarantee the performance and stability of the drive circuits during high-frequency operation. Second, because the drive circuit generates a large amount of heat when operating under high-frequency and high-power conditions, the heat dissipation capacity of existing circuits is insufficient, usually requiring external fans for cooling. This not only increases the complexity and cost of the equipment but may also lead to overheating and damage to circuit components due to poor heat dissipation. In addition, existing drive circuits are prone to failure during long-term operation and cannot properly protect the IGBT module. Once damaged, repair is difficult, further affecting the reliability and stability of the equipment.

[0005] In summary, existing drive circuits for induction heating power supplies for welding wire have significant shortcomings in terms of applicable frequency band, heat dissipation capacity, stability, and maintainability, making it difficult to meet the high reliability requirements of drive circuits for high-frequency, high-power, and long-term continuous operation of induction heating power supplies for welding wire. Therefore, developing an IGBT drive circuit with high reliability, high stability, good heat dissipation performance, and maintainability suitable for induction heating power supplies for welding wire has significant practical implications and broad application prospects. Utility Model Content

[0006] To overcome the shortcomings of existing technologies, this utility model provides an IGBT drive circuit for induction heating power supplies for welding wires. The technical solution of this utility model is as follows:

[0007] An IGBT drive circuit for a welding wire induction heating power supply includes:

[0008] The main drive circuit is used to realize optocoupler isolated input, level conversion, drive voltage on and off, and drive voltage drive output;

[0009] The first drive voltage control circuit is used to implement drive voltage control;

[0010] The second drive voltage control circuit works in conjunction with the first drive voltage control circuit to achieve precise control and stable output of the drive voltage.

[0011] The feedback circuit, in conjunction with the main drive circuit, the first drive voltage control circuit, and the second drive voltage control circuit, is used to implement second-order overcurrent protection.

[0012] The main drive circuit includes an isolation optocoupler U1, resistors R1, R2, R3, R4, R5, and R6, a switching diode D1, a capacitor C1, resistors R8, R9, R10, and R11, and transistors Q1, Q2, Q3, Q4, Q5, and Q6. The positive terminal of the PWM signal input is connected to one end of resistor R1, and the other end of resistor R1 is connected to pin 2 of the isolation optocoupler U1. The negative terminal of the PWM signal input is connected to pin 3 of the isolation optocoupler U1. Pin 5 of the isolation optocoupler U1 is grounded. Pin 6 of the isolation optocoupler U1 is connected to one end of resistors R2, R3, R4, and R5, as well as the cathode of switching diode D1, one end of capacitor C1, and one end of resistor R7. Pin 7 of the isolation optocoupler U1 is connected to BACK1, and pin 8 of the isolation optocoupler U1 is connected to a 5.1V voltage. R5 is connected in parallel, with its other end connected to a 24V power supply. The anode of the switching diode D1 is connected to one end of resistor R6, and the other end of resistor R6 is connected to the control voltage V3. The capacitor C1 and resistor R7 are connected in parallel, with their other ends connected to the base of transistor Q1. The emitter of transistor Q1, the collector of transistor Q2, and the collector of transistor Q6 are all grounded. The emitter of transistor Q2, the emitter of transistor Q3, the base of transistor Q6, and the base of transistor Q5 are all grounded. Connected to NET0, the emitter of transistor Q5 and the collector of transistor Q6 are connected to the OUT-G terminal. The collector of transistor Q1, the base of transistor Q2, and the base of transistor Q3 are connected to one end of resistors R8, R9, R10, and R11. Resistors R8, R9, R10, and R11 are connected in parallel, and the other end is connected to the control voltage V1. The collectors of transistor Q3 and Q5 are connected to a 24V voltage.

[0013] The first driving voltage control circuit includes a capacitor C5, a resistor R19, and a transistor Q7. One end of the capacitor C5, one end of the resistor R19, and the base of the transistor Q7 are connected to V3. The other end of the capacitor C5 is connected to the emitter of the transistor Q7 to a 5.1V voltage. The collector of the transistor Q7 is connected to one end of a resistor R20. The other end of the resistor R20 is connected to one end of a resistor R21 and the base of the transistor Q8. The other end of the resistor R19, the other end of the resistor R21, and the emitter of the transistor Q8 are connected to a 24V voltage. The collector of the transistor Q8 is connected to one end of a resistor R22. The other end of the resistor R22 is connected to V1.

[0014] The second driving voltage control circuit includes a resistor R23, a transistor Q9, a resistor R24, a resistor R26, a capacitor C7, and a transistor Q10. One end of the resistor R23 is connected to the collector of the transistor Q9, and the other end of the resistor R23 is grounded. The emitter of the transistor Q9, one end of the resistor R24, one end of the resistor R26, one end of the capacitor C7, and the collector of the transistor Q10 are connected to a 24V voltage. The base of the transistor Q9 is connected to the other end of the resistor R24, one end of the resistor R25, and one end of the capacitor C6. The resistor R25 and C6 are connected in parallel, and their other end is connected to the cathode of the Zener diode ZD2. The anode of the Zener diode ZD2 is connected to the other end of the capacitor C7, the emitter of Q10, and the anode of the diode D6. The base of the transistor Q10 is connected to the cathode of the diode D6, the other end of the resistor R26, and the anode of the fast recovery diode D7. The cathode of the fast recovery diode D7 is connected to the OUT_C1 terminal.

[0015] The feedback circuit includes capacitor C2, capacitor R16, resistors R12 and R13, and fast recovery diode D3. One end of capacitor C2 is connected to one end of resistors R16, R12, and R13, as well as the anode of fast recovery diode D3. The other end of capacitor C2 is connected to the other end of resistor R16, one end of capacitor C3, one end of resistor R17 and R18, the emitter of transistor Q4, and one end of capacitor C4. The cathodes of fast recovery diodes D3 and D4, and the anode of fast recovery diode D5 are connected to the OUT_C1 terminal. The cathode of capacitor C5 is connected to the OUT_C ​​terminal; the other end of capacitor C3 is connected to the anode of fast recovery diode D4, one end of resistor R14, the other end of resistor R17, one end of resistor R15, and the cathode of Zener diode ZD1. The other ends of resistor R14, R15, R13, and R12 are connected to the cathode of diode D2, and the anode of diode D2 is connected to NET0; the anode of Zener diode ZD1 is connected to the other end of resistor R18 and the base of transistor Q4, and the collector of transistor Q4 is connected to the other end of capacitor C4 and then to NET3.

[0016] The advantages of this utility model are:

[0017] 1. The isolated optocoupler U1 used has a large drive current and strong drive capability. This enables the drive circuit to stably output drive signals, effectively drive the IGBT module, ensure reliable operation of the welding wire induction heating power supply under high frequency and high power conditions, and improve the overall performance and stability of the equipment.

[0018] 2. Low power consumption design: The drive circuit has low power consumption, with a maximum power consumption of only 2W per channel. This low power consumption design not only helps reduce the overall energy consumption of the welding wire induction heating power supply and improve energy utilization efficiency, but also reduces the heat generated by the circuit, lowers the heat dissipation pressure, and is conducive to improving the stability and reliability of the circuit, thus extending the service life of the equipment.

[0019] 3. Comprehensive protection functions

[0020] First-order and second-order protection circuit lead-out points: When an abnormal current occurs in the circuit, the protection mechanism can be triggered in time to effectively protect the IGBT module from overcurrent damage and improve the safety of the circuit.

[0021] Interlock function: Pin 7 of U1 can be connected to the output of the protection circuit. In the event of an abnormality, the isolation optocoupler U1 can be directly shut down, realizing the interlock function. This design allows the drive signal to be quickly cut off in the event of a fault, preventing the fault from escalating further, ensuring the safe operation of the equipment, and improving the reliability and stability of the equipment.

[0022] 4. Modular Design: The drive circuit can be made into a modular design, making it easy to use. Modular design simplifies and speeds up circuit installation, maintenance, and replacement, reducing equipment maintenance costs and downtime, and improving equipment availability and reliability. Simultaneously, modular design facilitates circuit upgrades and expansion, better adapting to the needs of different users.

[0023] 5. Low-cost advantage: Fewer components are used, and all are general-purpose components, resulting in lower costs. Using general-purpose components not only reduces the manufacturing cost of the circuit but also makes its procurement and maintenance more convenient. The use of general-purpose components also improves the circuit's compatibility and replaceability, further reducing the equipment's operating costs and enhancing its cost-effectiveness.

[0024] 6. Strong versatility and wide adaptability bandwidth: The circuit boasts strong versatility and a wide adaptability bandwidth, making it particularly suitable for induction heating power supplies for welding wire with frequencies ranging from 10kHz to 50kHz. This wide bandwidth design allows the circuit to meet the requirements of different operating frequencies, exhibiting excellent versatility and applicability. It can adapt to the operating conditions of various induction heating power supplies for welding wire, providing users with more flexible and reliable options. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the main drive circuit of this utility model.

[0026] Figure 2 This is a schematic diagram of the first driving voltage control circuit of this utility model.

[0027] Figure 3 This is a schematic diagram of the second driving voltage control circuit of this utility model.

[0028] Figure 4 This is a schematic diagram of the feedback circuit of this utility model. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result of the description. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solution of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0030] See Figure 1 middle Figure 4 This utility model relates to an IGBT drive circuit for an induction heating power supply for welding wire, comprising:

[0031] The main drive circuit is used to realize optocoupler isolated input, level conversion, drive voltage on and off, and drive voltage drive output;

[0032] The first drive voltage control circuit is used to implement drive voltage control;

[0033] The second drive voltage control circuit works in conjunction with the first drive voltage control circuit to achieve precise control and stable output of the drive voltage.

[0034] The feedback circuit, in conjunction with the main drive circuit, the first drive voltage control circuit, and the second drive voltage control circuit, is used to implement second-order overcurrent protection.

[0035] The main drive circuit includes an isolation optocoupler U1, resistors R1, R2, R3, R4, R5, and R6, a switching diode D1, a capacitor C1, resistors R8, R9, R10, and R11, and transistors Q1, Q2, Q3, Q4, Q5, and Q6. The positive terminal of the PWM signal input is connected to one end of resistor R1, and the other end of resistor R1 is connected to pin 2 of the isolation optocoupler U1. The negative terminal of the PWM signal input is connected to pin 3 of the isolation optocoupler U1. Pin 5 of the isolation optocoupler U1 is grounded. Pin 6 of the isolation optocoupler U1 is connected to one end of resistors R2, R3, R4, and R5, as well as the cathode of switching diode D1, one end of capacitor C1, and one end of resistor R7. Pin 7 of the isolation optocoupler U1 is connected to BACK1, and pin 8 of the isolation optocoupler U1 is connected to a 5.1V voltage. The other end of resistor R5 is connected to a 24V power supply. The anode of switching diode D1 is connected to one end of resistor R6, and the other end of resistor R6 is connected to the control voltage V3. Capacitor C1 and resistor R7 are connected in parallel, and their other ends are both connected to the base of transistor Q1. The emitter of transistor Q1, the collector of transistor Q2, and the collector of transistor Q6 are all grounded. The emitter of transistor Q2, the emitter of transistor Q3, the base of transistor Q6, and the base of transistor Q5 are connected... The emitter of transistor Q5 and the collector of transistor Q6 are connected to OUT-G. The collector of transistor Q1, the base of transistor Q2, and the base of transistor Q3 are connected to one end of resistors R8, R9, R10, and R11. Resistors R8, R9, R10, and R11 are connected in parallel, and their other ends are connected to the control voltage V1. The collectors of transistor Q3 and Q5 are connected to a 24V voltage.

[0036] Based on the configuration of this main drive circuit, the following advantages are achieved:

[0037] I. Achieving Optically Isolated Input

[0038] Enhanced safety: Optical isolation of the input signal is achieved through the isolation optocoupler U1, which can effectively isolate the circuits at the input and output ends, avoid interference and damage to the control circuit by high voltage or strong current, and improve the safety and reliability of the circuit.

[0039] Enhanced anti-interference capability: Optical isolation can effectively suppress common-mode interference and electromagnetic interference, ensure stable transmission of PWM signals, enhance the circuit's anti-interference capability in complex electromagnetic environments, and ensure the stable operation of the welding wire induction heating power supply.

[0040] II. Implementing Level Conversion

[0041] Adapting to different signal levels: The main drive circuit, through the configuration of components such as resistors R1, R2, R3, R4, and R5, can realize the conversion of different signal levels, converting the input PWM signal into a level signal suitable for driving the IGBT module, ensuring the normal operation of the IGBT module under different working conditions.

[0042] Improved signal compatibility: The level conversion function enables the main drive circuit to be compatible with control signals of different level standards, enhancing the circuit's versatility and applicability, and facilitating connection and integration with various control systems.

[0043] III. Implementing the opening and closing of the driving voltage

[0044] Precise control of drive voltage: Through the coordinated operation of components such as transistors Q1, Q2, Q3, Q4, Q5 and Q6, the main drive circuit can precisely control the opening and closing of the drive voltage, ensuring that the IGBT module can be turned on or off in time when needed, thus improving the control accuracy and response speed of the welding wire induction heating power supply.

[0045] Improve energy efficiency: Precise drive voltage control can avoid unnecessary energy waste, improve energy efficiency, reduce equipment operating costs, and also help reduce equipment heat generation, thereby improving equipment stability and reliability.

[0046] IV. Achieving Drive Voltage Drive Output

[0047] Providing a stable drive signal: The main drive circuit, through the configuration of components such as resistors R6, R7, R8, R9, R10, and R11, can provide a stable and reliable drive signal output, ensuring the stable drive of the IGBT module under various working conditions and improving the overall performance and stability of the welding wire induction heating power supply.

[0048] Enhanced driving capability: The circuit design employs multiple transistors for signal amplification and driving, enhancing the driving capability of the drive circuit. This enables it to meet the driving requirements of high-power IGBT modules and ensures the normal operation of the welding wire induction heating power supply under high-power conditions.

[0049] V. Reasonable circuit structure

[0050] Compact component layout: The components in the main drive circuit are compactly arranged and have clear connections, which reduces the parasitic inductance and capacitance of the circuit, reduces signal transmission delay and loss, and improves the response speed and stability of the circuit.

[0051] Excellent heat dissipation performance: The circuit design fully considers heat dissipation issues. Through reasonable component layout and heat dissipation measures, the temperature of the circuit can be effectively reduced, the reliability and lifespan of the circuit can be improved, and the stability and safety of the welding wire induction heating power supply during long-term operation can be ensured.

[0052] The first driving voltage control circuit includes a capacitor C5, a resistor R19, and a transistor Q7. One end of the capacitor C5, one end of the resistor R19, and the base of the transistor Q7 are connected to V3. The other end of the capacitor C5 is connected to the emitter of the transistor Q7 to a 5.1V voltage. The collector of the transistor Q7 is connected to one end of a resistor R20. The other end of the resistor R20 is connected to one end of a resistor R21 and the base of the transistor Q8. The other end of the resistor R19, the other end of the resistor R21, and the emitter of the transistor Q8 are connected to a 24V voltage. The collector of the transistor Q8 is connected to one end of a resistor R22. The other end of the resistor R22 is connected to V1.

[0053] Based on the configuration of this first driving voltage control circuit, the following advantages are achieved:

[0054] I. Precise drive voltage control

[0055] Stable voltage output: The configuration of capacitor C5 and resistor R19 enables precise control and adjustment of the drive voltage, ensuring a stable and reliable output drive voltage. This provides a stable drive signal for the IGBT module and helps improve the control accuracy and stability of the welding wire induction heating power supply.

[0056] Fast response speed: The use of transistors Q7 and Q8 enables the circuit to respond quickly to changes in the input signal and adjust the output of the drive voltage in a timely manner to meet the requirements of the welding wire induction heating power supply under high-frequency operating conditions and ensure the efficient operation of the equipment.

[0057] II. Effective Voltage Distribution and Current Limiting

[0058] Reasonable voltage distribution: The configuration of resistors R20 and R21 enables reasonable distribution of the driving voltage, ensuring that each part of the circuit receives the appropriate voltage, avoiding damage to components caused by excessively high or low voltage, and improving the reliability and stability of the circuit.

[0059] Current limiting protection function: Resistors R19 and R21 not only participate in voltage distribution, but also have a current limiting function. They can limit the current in the circuit and prevent excessive current from damaging components such as transistors Q7 and Q8, thus playing a certain protective role and extending the service life of the circuit.

[0060] III. Good circuit compatibility

[0061] Adaptable to different voltage standards: This circuit design can adapt to different voltage standards. By adjusting the parameters of the resistor and capacitor, it can meet the driving voltage requirements of different welding wire induction heating power supplies. It has good versatility and compatibility, making it convenient to use in different devices.

[0062] Working in conjunction with other circuit modules: The first drive voltage control circuit works in conjunction with the main drive circuit and other circuit modules to achieve stable operation of the entire welding wire induction heating power supply system. The signal transmission between modules is stable, the collaborative work effect is good, and the overall performance of the equipment is improved.

[0063] IV. Lower power consumption

[0064] High-efficiency energy conversion: The reasonable selection and configuration of components in the circuit can achieve high-efficiency energy conversion, reduce energy loss during transmission and conversion, reduce the power consumption of the entire welding wire induction heating power supply, improve energy utilization efficiency, and meet the requirements of energy conservation and environmental protection.

[0065] Reduced heat generation: Lower power consumption means less heat generated by the circuit, which helps to reduce the temperature of the circuit, reduce heat dissipation pressure, improve the stability and reliability of the circuit, and extend the service life of the device.

[0066] The second driving voltage control circuit includes a resistor R23, a transistor Q9, a resistor R24, a resistor R26, a capacitor C7, and a transistor Q10. One end of the resistor R23 is connected to the collector of the transistor Q9, and the other end of the resistor R23 is grounded. The emitter of the transistor Q9, one end of the resistor R24, one end of the resistor R26, one end of the capacitor C7, and the collector of the transistor Q10 are connected to a 24V voltage. The base of the transistor Q9 is connected to the other end of the resistor R24, one end of the resistor R25, and one end of the capacitor C6. The resistor R25 and C6 are connected in parallel, and their other end is connected to the cathode of the Zener diode ZD2. The anode of the Zener diode ZD2 is connected to the other end of the capacitor C7, the emitter of Q10, and the anode of the diode D6. The base of the transistor Q10 is connected to the cathode of the diode D6, the other end of the resistor R26, and the anode of the fast recovery diode D7. The cathode of the fast recovery diode D7 is connected to the OUT_C1 terminal.

[0067] The advantages of this second drive voltage control circuit are as follows:

[0068] I. Precise drive voltage control and stable output

[0069] Stable voltage output: The configuration of resistors R23, R24, R26 and capacitor C7 enables precise control and regulation of the drive voltage, ensuring a stable and reliable output drive voltage. This provides a stable drive signal for the IGBT module, helping to improve the control accuracy and stability of the welding wire induction heating power supply and ensuring reliable operation of the equipment under various working conditions.

[0070] Fast response speed: The use of transistors Q9 and Q10 enables the circuit to respond quickly to changes in the input signal and adjust the output drive voltage in a timely manner. This is crucial for the stable operation of the welding wire induction heating power supply under high-frequency working conditions, ensuring efficient operation of the equipment and meeting the requirements of high-frequency, high-power operation.

[0071] II. Effective voltage distribution and current limiting protection

[0072] Proper voltage distribution: The configuration of resistors R24 and R26 enables a reasonable distribution of the driving voltage, ensuring that each part of the circuit receives the appropriate voltage. This avoids damage to components caused by excessively high or low voltage, improves the reliability and stability of the circuit, and extends the service life of the components.

[0073] Current limiting protection: Resistors R23 and R24 not only participate in voltage distribution but also limit current, preventing excessive current from damaging components such as transistors Q9 and Q10. This provides a certain level of protection, improves circuit stability and reliability, and reduces equipment maintenance costs and downtime.

[0074] III. Enhanced circuit protection functions

[0075] Zener diode protection: The use of Zener diode ZD2 provides voltage regulation protection for the circuit. When the voltage in the circuit exceeds the Zener diode's regulation value, the Zener diode will conduct, clamping the excessive voltage to a safe range, thereby protecting other components in the circuit from overvoltage damage and improving the circuit's reliability and stability.

[0076] Diode protection: The configuration of diode D6 and fast recovery diode D7 prevents reverse current in the circuit from damaging components. When the current direction in the circuit changes, the diode quickly turns on or off, ensuring that the current can only flow in one direction, thereby protecting transistor Q10 and other components and improving the stability and reliability of the circuit.

[0077] IV. Good circuit compatibility and versatility

[0078] Adaptable to different voltage standards: This circuit design is adaptable to different voltage standards. By adjusting the parameters of the resistors and capacitors, the driving voltage requirements of different welding wire induction heating power supplies can be met. This gives the circuit good versatility and compatibility, making it convenient to use in different devices and meeting the needs of different users.

[0079] Working in conjunction with other circuit modules: The second drive voltage control circuit, in cooperation with the main drive circuit, the first drive voltage control circuit, and other circuit modules, enables the stable operation of the entire welding wire induction heating power supply system. Stable signal transmission between modules and good collaborative performance improve the overall performance and reliability of the equipment, ensuring its efficient operation.

[0080] The feedback circuit includes capacitor C2, capacitor R16, resistors R12 and R13, and fast recovery diode D3. One end of capacitor C2 is connected to one end of resistors R16, R12, and R13, as well as the anode of fast recovery diode D3. The other end of capacitor C2 is connected to the other end of resistor R16, one end of capacitor C3, one end of resistor R17 and R18, the emitter of transistor Q4, and one end of capacitor C4. The cathodes of fast recovery diodes D3 and D4, and the anode of fast recovery diode D5 are connected to the OUT_C1 terminal. The cathode of capacitor C5 is connected to the OUT_C ​​terminal; the other end of capacitor C3 is connected to the anode of fast recovery diode D4, one end of resistor R14, the other end of resistor R17, one end of resistor R15, and the cathode of Zener diode ZD1. The other ends of resistor R14, R15, R13, and R12 are connected to the cathode of diode D2, and the anode of diode D2 is connected to NET0; the anode of Zener diode ZD1 is connected to the other end of resistor R18 and the base of transistor Q4, and the collector of transistor Q4 is connected to the other end of capacitor C4 and then to NET3.

[0081] The advantages of this feedback circuit are as follows:

[0082] I. Implement second-order overcurrent protection function

[0083] Timely monitoring and feedback: The feedback circuit, through the configuration of components such as capacitor C2, resistors R16, R12, R13, and fast recovery diode D3, can monitor the current signal in the circuit in real time. When an overcurrent condition is detected, it can quickly feed the signal back to the main drive circuit and the drive voltage control circuit, ensuring the safe operation of the IGBT module, effectively avoiding equipment damage caused by overcurrent, and improving the reliability and stability of the equipment.

[0084] Multi-level protection mechanism: This feedback circuit is designed with second-order overcurrent protection. Through the cooperation of multiple fast recovery diodes (D3, D4, D5) and resistors and capacitors, it realizes multi-level processing and protection of overcurrent signals. This multi-level protection mechanism can more accurately judge the overcurrent situation and take protective measures in a timely manner, improving the sensitivity and reliability of protection and providing more comprehensive safety assurance for the equipment.

[0085] II. Enhancing the stability and reliability of the circuit

[0086] Stable signal transmission: The use of capacitors C2 and C3 filters and stabilizes the feedback signal, reducing interference and noise during signal transmission and ensuring the accuracy and stability of the feedback signal. This helps improve the stability and reliability of the entire welding wire induction heating power supply system, avoiding misoperation or equipment failure caused by unstable signals.

[0087] The coordinated operation of protection components: The various components in the feedback circuit (such as fast recovery diodes, Zener diodes, transistors, etc.) work together to form a complete protection network. When an abnormality occurs in the circuit, these components can respond quickly, cooperate with each other, and promptly cut off the drive signal or adjust the drive voltage to protect the IGBT module and other critical components, extending the service life of the equipment.

[0088] III. Improve the response speed of the circuit

[0089] Fast Overcurrent Protection Response: The use of fast recovery diodes D3, D4, and D5 enables the feedback circuit to respond quickly to overcurrent signals. These diodes have fast switching speeds and low forward voltage drops, allowing them to transmit overcurrent signals to the protection circuit in a short time, triggering the protection mechanism and effectively preventing equipment damage caused by overcurrent, thus improving equipment safety and reliability. Timely Signal Feedback: The feedback circuit, through the configuration of components such as resistors R16, R12, and R13, can quickly feed back overcurrent signals to the main drive circuit and drive voltage control circuit. This timely signal feedback mechanism allows the circuit to quickly adjust the drive signal or cut off the power supply, ensuring safe operation of the equipment under abnormal conditions and improving the equipment's response speed and stability. IV. Good Circuit Compatibility and Versatility

[0090] Adaptable to various circuit systems: This feedback circuit is rationally designed and can adapt to different circuit systems and equipment. By adjusting the parameters of the resistor and capacitor, the feedback signal requirements of different welding wire induction heating power supplies can be met, demonstrating good versatility and compatibility. This allows the feedback circuit to be used in a variety of devices, providing flexible choices for different users.

[0091] Working in conjunction with other circuit modules: The feedback circuit, main drive circuit, first drive voltage control circuit, second drive voltage control circuit, and other circuit modules work together to ensure the stable operation of the entire welding wire induction heating power supply system. Stable signal transmission between modules and good collaborative performance improve the overall performance and reliability of the equipment, ensuring its efficient operation.

[0092] The working principle of this utility model is as follows:

[0093] The main drive circuit is the core of the entire IGBT drive circuit, responsible for implementing optocoupler-isolated input, level conversion, turning the drive voltage on and off, and driving the output voltage. The specific working process is as follows:

[0094] Optocoupler-isolated input: The positive terminal of the PWM signal input is connected to pin 2 of the optocoupler U1 via resistor R1, the negative terminal of the PWM signal input is connected to pin 3 of the optocoupler U1, and pin 5 is grounded. In this way, optocoupler U1 achieves optical isolation of the input signal, improving circuit safety and anti-interference capabilities.

[0095] Level Shifting: Pin 6 of the isolation optocoupler U1 is connected to one end of resistors R2, R3, R4, and R5, as well as the cathode of switching diode D1, capacitor C1, and one end of resistor R7. Resistors R2, R3, R4, and R5 are connected in parallel, with the other end connected to a 24V power supply. Capacitor C1 and resistor R7 are connected in parallel, with the other end connected to the base of transistor Q1. This configuration of components achieves level shifting, converting the input PWM signal into a level signal suitable for driving the IGBT module.

[0096] Driving voltage on / off: Transistors Q1, Q2, Q3, Q4, Q5, and Q6 work together to control the on / off state of the driving voltage. When the PWM signal is high, optocoupler U1 is turned on, current flows to the base of transistor Q1, Q1 conducts, and this controls the states of transistors Q2, Q3, etc., ultimately achieving the output of the driving voltage. When the PWM signal is low, optocoupler U1 is turned off, no current flows to the base of transistor Q1, Q1 is turned off, and the driving voltage is turned off.

[0097] Drive voltage output: The collector of transistor Q1, the base of Q2, and the base of Q3 are connected to one end of resistors R8, R9, R10, and R11. The other end of resistors R8, R9, R10, and R11, connected in parallel, is connected to the control voltage V1. The collectors of transistors Q3 and Q5 are connected to a 24V voltage. This configuration of components ensures a stable output drive voltage, providing a reliable drive signal for the IGBT module.

[0098] The first drive voltage control circuit is mainly used to control the drive voltage, ensuring a stable and accurate output. The specific working process is as follows:

[0099] Voltage control: One end of capacitor C5, one end of resistor R19, and the base of transistor Q7 are connected to V3, and the other end of capacitor C5 and the emitter of transistor Q7 are connected to 5.1V. In this way, the drive voltage is initially controlled and regulated through the configuration of capacitor C5 and resistor R19.

[0100] Signal amplification: The collector of transistor Q7 is connected to one end of resistor R20, and the other end of resistor R20 is connected to one end of resistor R21 and the base of transistor Q8. The other ends of resistors R19 and R21, as well as the collector of transistor Q8, are connected to a 24V voltage. Through the amplification effect of transistors Q7 and Q8, the control capability of the drive voltage is further enhanced, ensuring a stable output of the drive voltage.

[0101] Output adjustment: The collector of transistor Q8 is connected to one end of resistor R22, and the other end of resistor R22 is connected to V1. The configuration of resistor R22 further adjusts the drive voltage to ensure that the output drive voltage meets the requirements of the IGBT module.

[0102] The second drive voltage control circuit works in conjunction with the first drive voltage control circuit to achieve precise control and stable output of the drive voltage. The specific working process is as follows:

[0103] Voltage distribution: One end of resistor R23 is connected to the collector of transistor Q9, and the other end of resistor R23 is grounded. The emitter of transistor Q9, one end of resistor R24, one end of resistor R26, one end of capacitor C7, and the collector of transistor Q10 are connected to a 24V voltage. This component configuration achieves a reasonable distribution of the drive voltage, ensuring that each part of the circuit receives the appropriate voltage.

[0104] Signal amplification and protection: The base of transistor Q9 is connected to the other end of resistor R24, one end of resistor R25, and one end of capacitor C6. Resistor R25 and C6 are connected in parallel, and their other end is connected to the cathode of Zener diode ZD2. The anode of Zener diode ZD2 is connected to the other end of capacitor C7, the emitter of Q10, and the anode of diode D6. Through the amplification effect of transistors Q9 and Q10, and the protection effect of Zener diode ZD2, precise control and stable output of the drive voltage are achieved, while overvoltage protection is also provided.

[0105] Output regulation: The base of transistor Q10 is connected to the cathode of diode D6, the other end of resistor R26, and the anode of fast recovery diode D7. The cathode of fast recovery diode D7 is connected to the OUT_C1 terminal. This configuration of components further regulates and protects the drive voltage, ensuring a stable and reliable output drive voltage.

[0106] The feedback circuit, in conjunction with the main drive circuit, the first drive voltage control circuit, and the second drive voltage control circuit, is used to implement second-order overcurrent protection. The specific operation is as follows: Overcurrent monitoring: One end of capacitor C2 is connected to one end of resistor R16, one end of resistor R12, one end of resistor R13, and the anode of fast recovery diode D3. The other end of capacitor C2 is connected to the other end of resistor R16, one end of capacitor C3, one end of resistor R17, one end of resistor R18, the emitter of transistor Q4, and one end of capacitor C4. Through this component configuration, the current signal in the circuit is monitored in real time. When an overcurrent condition is detected, the signal is quickly fed back to the main drive circuit and the drive voltage control circuit.

[0107] Overcurrent protection: The cathodes of fast recovery diodes D3 and D4, and the anode of fast recovery diode D5 are connected to the OUT_C1 terminal, while the cathode of fast recovery diode D5 is connected to the OUT_C ​​terminal. When an overcurrent signal is detected, the fast recovery diodes quickly conduct, transmitting the overcurrent signal to the protection circuit, triggering the protection mechanism, and promptly cutting off the drive signal or adjusting the drive voltage to protect the IGBT module and other critical components.

[0108] Signal processing: The other end of capacitor C3 is connected to the anode of fast recovery diode D4, one end of resistor R14, the other end of resistor R17, one end of resistor R15, and the cathode of Zener diode ZD1. The other ends of resistors R14, R15, R13, and R12 are connected to the cathode of diode D2, and the anode of diode D2 is connected to NET0. Through this configuration of components, the feedback signal is filtered and processed to ensure signal accuracy and stability, improving the sensitivity and reliability of the protection.

[0109] Protection and control: The anode of Zener diode ZD1 is connected to the other end of resistor R18 and the base of transistor Q4. The collector of transistor Q4 is connected to the other end of capacitor C4 and then to NET3. When an overcurrent signal is detected, transistor Q4 conducts, further controlling the operation of the protection circuit to ensure the safe operation of the equipment.

[0110] Through the coordinated operation of the above components, the IGBT drive circuit of this invention can achieve stable driving and effective protection of the welding wire induction heating power supply, ensuring reliable operation of the equipment under high frequency and high power conditions.

[0111] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An IGBT drive circuit for an induction heating power supply for welding wire, characterized in that, include: The main drive circuit is used to realize optocoupler isolated input, level conversion, drive voltage on and off, and drive voltage drive output; The first drive voltage control circuit is used to implement drive voltage control; The second drive voltage control circuit works in conjunction with the first drive voltage control circuit to achieve precise control and stable output of the drive voltage. The feedback circuit, in conjunction with the main drive circuit, the first drive voltage control circuit, and the second drive voltage control circuit, is used to implement second-order overcurrent protection.

2. The IGBT drive circuit for induction heating power supply of welding wire according to claim 1, characterized in that, The main drive circuit includes an isolation optocoupler U1, resistors R1, R2, R3, R4, R5, and R6, a switching diode D1, a capacitor C1, resistors R8, R9, R10, and R11, and transistors Q1, Q2, Q3, Q4, Q5, and Q6. The positive terminal of the PWM signal input is connected to one end of resistor R1, and the other end of resistor R1 is connected to pin 2 of the isolation optocoupler U1. The negative terminal of the PWM signal input is connected to pin 3 of the isolation optocoupler U1. Pin 5 of the isolation optocoupler U1 is grounded. Pin 6 of the isolation optocoupler U1 is connected to one end of resistors R2, R3, R4, and R5, as well as the cathode of switching diode D1, one end of capacitor C1, and one end of resistor R7. Pin 7 of the isolation optocoupler U1 is connected to BACK1, and pin 8 of the isolation optocoupler U1 is connected to a 5.1V voltage. The other end of resistor R5 is connected to a 24V power supply. The anode of switching diode D1 is connected to one end of resistor R6, and the other end of resistor R6 is connected to the control voltage V3. Capacitor C1 and resistor R7 are connected in parallel, and their other ends are both connected to the base of transistor Q1. The emitter of transistor Q1, the collector of transistor Q2, and the collector of transistor Q6 are all grounded. The emitter of transistor Q2, the emitter of transistor Q3, the base of transistor Q6, and the base of transistor Q5 are connected... The emitter of transistor Q5 and the collector of transistor Q6 are connected to OUT-G. The collector of transistor Q1, the base of transistor Q2, and the base of transistor Q3 are connected to one end of resistors R8, R9, R10, and R11. Resistors R8, R9, R10, and R11 are connected in parallel, and their other ends are connected to the control voltage V1. The collectors of transistor Q3 and Q5 are connected to a 24V voltage.

3. The IGBT drive circuit for induction heating power supply of welding wire according to claim 1, characterized in that, The first driving voltage control circuit includes a capacitor C5, a resistor R19, and a transistor Q7. One end of the capacitor C5, one end of the resistor R19, and the base of the transistor Q7 are connected to V3. The other end of the capacitor C5 is connected to the emitter of the transistor Q7 to a 5.1V voltage. The collector of the transistor Q7 is connected to one end of a resistor R20. The other end of the resistor R20 is connected to one end of a resistor R21 and the base of the transistor Q8. The other end of the resistor R19, the other end of the resistor R21, and the emitter of the transistor Q8 are connected to a 24V voltage. The collector of the transistor Q8 is connected to one end of a resistor R22. The other end of the resistor R22 is connected to V1.

4. The IGBT drive circuit for induction heating power supply of welding wire according to claim 3, characterized in that, The second driving voltage control circuit includes a resistor R23, a transistor Q9, a resistor R24, a resistor R26, a capacitor C7, and a transistor Q10. One end of the resistor R23 is connected to the collector of the transistor Q9, and the other end of the resistor R23 is grounded. The emitter of the transistor Q9, one end of the resistor R24, one end of the resistor R26, one end of the capacitor C7, and the collector of the transistor Q10 are connected to a 24V voltage. The base of the transistor Q9 is connected to the other end of the resistor R24, one end of the resistor R25, and one end of the capacitor C6. The resistor R25 and C6 are connected in parallel, and their other end is connected to the cathode of the Zener diode ZD2. The anode of the Zener diode ZD2 is connected to the other end of the capacitor C7, the emitter of Q10, and the anode of the diode D6. The base of the transistor Q10 is connected to the cathode of the diode D6, the other end of the resistor R26, and the anode of the fast recovery diode D7. The cathode of the fast recovery diode D7 is connected to the OUT_C1 terminal.

5. The IGBT drive circuit for induction heating power supply of welding wire according to claim 4, characterized in that, The feedback circuit includes capacitor C2, capacitor R16, resistors R12 and R13, and fast recovery diode D3. One end of capacitor C2 is connected to one end of resistors R16, R12, and R13, as well as the anode of fast recovery diode D3. The other end of capacitor C2 is connected to the other end of resistor R16, one end of capacitor C3, one end of resistor R17 and R18, the emitter of transistor Q4, and one end of capacitor C4. The cathodes of fast recovery diodes D3 and D4 are connected to... The anode of the fast recovery diode D5 is connected to the OUT_C1 terminal; the cathode of the fast recovery diode D5 is connected to the OUT_C ​​terminal; the other end of the capacitor C3 is connected to the anode of the fast recovery diode D4, one end of resistor R14, the other end of resistor R17, one end of resistor R15, and the cathode of the Zener diode ZD1; the other ends of resistor R14, R15, R13, and R12 are connected to the cathode of diode D2, and the anode of diode D2 is connected to NET0; The anode of the Zener diode ZD1 is connected to the other end of the resistor R18 and the base of the transistor Q4. The collector of the transistor Q4 is connected to the other end of the capacitor C4 and then connected to NET3.

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