Intelligent high-frequency arc striking circuit

Abstract

The application discloses a kind of intelligent high-frequency arc starting circuit, include: MCU, charging control circuit, discharge control circuit and high-frequency inductor;MCU is used to send charging control signal and discharge control signal;Charging control circuit is connected with MCU, for receiving and processing charging control signal;Discharge control circuit is connected with MCU, for receiving and processing discharge control signal;High-frequency inductor terminal 1 is connected with charging control circuit, high-frequency inductor terminal 2 is connected with discharge control circuit, high-frequency inductor terminal 3,4 is connected with the output main circuit of external electric welding machine.This application can adjust the frequency and voltage control of high-frequency high-voltage arc starting circuit, for different use, select different working frequency and working voltage, can effectively reduce high-frequency interference, reduce the radiation damage to the person.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of arc starting circuit of argon arc welding machine, and particularly relates to an intelligent high-frequency arc starting circuit. BACKGROUND

[0002] In the argon arc welding machine, in order to improve the work efficiency, the most common arc starting mode is high-frequency high-voltage arc starting. The high-frequency high-voltage arc starting is efficient, but it will introduce strong electromagnetic interference, which will disturb the surrounding electrical products and cause strong interference to the argon arc welding machine itself. SUMMARY

[0003] According to the application, an intelligent high-frequency arc starting circuit is provided, which comprises an MCU, a charging control circuit, a discharging control circuit and a high-frequency inductor.

[0004] The MCU is used to send charging control signals and discharging control signals.

[0005] The charging control circuit is connected with the MCU and is used to receive and process the charging control signals.

[0006] The discharging control circuit is connected with the MCU and is used to receive and process the discharging control signals.

[0007] The terminal 1 of the high-frequency inductor is connected with the charging control circuit, the terminal 2 of the high-frequency inductor is connected with the discharging control circuit, and the terminals 3 and 4 of the high-frequency inductor are connected with the output main circuit of the external electric welding machine.

[0008] Further, the charging control circuit comprises a boost control chip, a first resistor, a first MOS tube, a second resistor, a third resistor, a first capacitor, a boost transformer, a first diode and a second capacitor.

[0009] The pin 1 of the boost control chip is connected with the MCU, the pin 6 of the boost control chip is connected with one end of the first resistor, and the pin 3 of the boost control chip is connected with one end of the second resistor.

[0010] The other end of the first resistor is connected with the gate of the first MOS tube.

[0011] The other end of the second resistor is connected with the source of the first MOS tube and one end of the third resistor.

[0012] The other end of the third resistor is grounded.

[0013] The drain of the first MOS tube is connected with the terminal 1 of the boost transformer.

[0014] The terminal 2 of the boost transformer is connected with the VCC port and grounded through the first capacitor, and the terminal HV of the boost transformer is connected with the anode of the first diode.

[0015] The negative electrode of the first diode is connected with the terminal 1 of the high-frequency inductor and one end of the second capacitor.

[0016] The other end of the second capacitor is connected with the terminal 3 of the step-up transformer and then grounded.

[0017] Further, the charging control circuit further comprises a third capacitor, one end of the third capacitor is connected between the pin 3 of the step-up control chip and one end of the second resistor, and the other end of the third capacitor is grounded.

[0018] Further, the charging control circuit further comprises a fourth resistor and a fourth capacitor.

[0019] One end of the fourth resistor is connected with the pin 8 of the step-up control chip.

[0020] One end of the fourth capacitor is connected with the pin 4 of the step-up control chip and the other end of the fourth resistor, and the other end of the fourth capacitor is grounded.

[0021] Further, the discharging control circuit comprises a fifth resistor, a second MOS tube, a bidirectional breakdown diode, an isolation driving transformer, a sixth resistor, a second diode, a thyristor and a hardware protection circuit.

[0022] One end of the fifth resistor is connected with the MCU.

[0023] The gate of the second MOS tube is connected with the other end of the fifth resistor, the source of the second MOS tube is grounded, the drain of the second MOS tube is connected with one end of the bidirectional breakdown diode and the terminal 2 of the isolation driving transformer.

[0024] The terminal 1 of the isolation driving transformer is connected with one end of the bidirectional breakdown diode and then connected with the VCC port, the terminal 3 of the isolation driving transformer is connected with one end of the sixth resistor, and the terminal 4 of the isolation driving transformer is grounded.

[0025] The other end of the sixth resistor is connected with the positive electrode of the second diode.

[0026] The negative electrode of the second diode is connected with the gate of the thyristor.

[0027] The cathode of the thyristor is grounded, and the anode of the thyristor is connected with the terminal 2 of the high-frequency inductor.

[0028] The hardware protection circuit is connected with the gate and the anode of the thyristor.

[0029] Further, the hardware protection circuit comprises a voltage stabilizing tube and a seventh resistor.

[0030] One end of the voltage stabilizing tube is connected with the anode of the thyristor.

[0031] One end of the seventh resistor is connected with one end of the voltage stabilizing tube, and the other end of the seventh resistor is connected between the gate of the thyristor and the negative electrode of the second diode.

[0032] Further, the discharge control circuit further comprises a third diode, a negative electrode of the third diode being connected between the sixth resistor and the second diode, and the other end of the third diode being grounded.

[0033] Further, the discharge control circuit further comprises an eighth resistor and a fifth capacitor.

[0034] One end of the eighth resistor is connected between the gate of the thyristor and the negative electrode of the second diode, and the other end of the eighth resistor is grounded.

[0035] One end of the fifth capacitor is connected between the one end of the eighth resistor and the gate of the thyristor, and the other end of the fifth capacitor is grounded.

[0036] Further, the discharge control circuit further comprises a ninth resistor, one end of the ninth resistor being connected between the other end of the fifth resistor and the gate of the second MOS tube, and the other end of the ninth resistor being connected to the source of the second MOS tube and then grounded.

[0037] According to the intelligent high-frequency arc striking circuit, the frequency and voltage of the high-frequency high-voltage arc striking circuit can be controlled, different working frequencies and working voltages can be selected according to different use cases, and high-frequency interference can be effectively reduced, and radiation damage to the human body can be reduced.

[0038] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the subject technology claimed. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The circuit diagram of the intelligent high-frequency arc striking circuit according to the embodiment of the present application. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, and the present application will be further described.

[0041] Firstly, the intelligent high-frequency arc striking circuit according to the embodiment of the present application will be described. Figure 1 The intelligent high-frequency arc striking circuit according to the embodiment of the present application is used for arc striking of argon arc welding, and has a wide range of application scenarios.

[0042] As shown in Figure 1 , the intelligent high-frequency arc striking circuit according to the embodiment of the present application comprises an MCU, a charging control circuit, a discharge control circuit and a high-frequency inductor TR2.

[0043] Specifically, as shown in Figure 1 , the MCU is used to send a charging control signal and a discharge control signal.

[0044] Specifically, as shown in Figure 1 , the charging control circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a first MOS tube M1 and a second MOS tube M2.As shown, the charging control circuit is connected with the MCU for receiving and processing the charging control signal. The charging control circuit comprises: a boost control chip U1, a first resistor R1, a first MOS tube T1, a second resistor R2, a third resistor R3, a first capacitor C3, a boost transformer TR1, a first diode D1 and a second capacitor C4. The pin 1 of the boost control chip U1 is connected with the MCU, the pin 6 of the boost control chip U1 is connected with one end of the first resistor R1, and the pin 3 of the boost control chip U1 is connected with one end of the second resistor R2. The other end of the first resistor R1 is connected with the gate of the first MOS tube T1, the first resistor R1 is used for limiting the current flowing from the output pin of the boost control chip U1 to the first MOS tube T1, and also plays a certain impedance matching role, so that the output pin of the boost control chip U1 and the input stage (gate) of the first MOS tube T1 can work better together, ensuring effective transmission of signals and reducing adverse effects such as signal reflection. The other end of the second resistor R2 is connected with the source of the first MOS tube T1 and one end of the third resistor R3. The other end of the third resistor R3 is grounded. The drain of the first MOS tube T1 is connected with the terminal 1 of the boost transformer TR1. The first MOS tube T1 serves as a switching element. When the OUT pin of the boost control chip U1 outputs a high-level signal, the gate-source voltage of the first MOS tube T1 is greater than its opening threshold voltage through the first resistor R1, and the first MOS tube T1 is turned on. At this time, the power supply supplies power to the primary winding of the boost transformer TR1 through the first MOS tube T1. When the OUT pin of the boost control chip U1 outputs a low-level signal, the gate-source voltage of the first MOS tube T1 is lower than the opening threshold voltage, the first MOS tube T1 is cut off, and the power supply to the boost transformer TR1 is stopped. The first MOS tube T1 can also control a larger current to pass through the boost transformer TR1, realize conversion of electric energy, convert the input DC electric energy into high-frequency pulse electric energy, provide an input signal for the subsequent boost transformer TR1, and is one of the key elements for realizing the boost function. The terminal 2 of the boost transformer TR1 is connected with the VCC port, and then grounded through the first capacitor C3. The terminal HV of the boost transformer TR1 is connected with the anode of the first diode D1. The cathode of the first diode D1 is connected with the terminal 1 of the high-frequency inductor TR2 and one end of the second capacitor C4. The other end of the second capacitor C4 is connected with the terminal 3 of the boost transformer TR1 and then grounded.

[0045] Further, as shown in FIG. 2, the charging control circuit further comprises: a third capacitor C2, one end of the third capacitor C2 being connected between the pin 3 of the boost control chip U1 and one end of the second resistor R2, and the other end of the third capacitor C2 being grounded. The third capacitor C2 is used for filtering. Figure 1

[0046] Further, as shown in FIG. 2, the charging control circuit further comprises: a third capacitor C2, one end of the third capacitor C2 being connected between the pin 3 of the boost control chip U1 and one end of the second resistor R2, and the other end of the third capacitor C2 being grounded. The third capacitor C2 is used for filtering. Figure 1 ​As shown, the charging control circuit further includes: a fourth resistor R4 and a fourth capacitor C1; one end of the fourth resistor R4 is connected to pin 8 of the boost control chip U1; one end of the fourth capacitor C1 is connected to pin 4 of the boost control chip U1 and the other end of the fourth resistor R4, and the other end of the fourth capacitor C1 is grounded.

[0047] Specifically, if Figure 1 As shown, the discharge control circuit is connected to the MCU and is used to receive and process the discharge control signal. The discharge control circuit includes: a fifth resistor R5, a second MOS transistor Q1, a bidirectional breakdown diode Z2, an isolation drive transformer TR3, a sixth resistor R7, a second diode D3, a thyristor T2, and a hardware protection circuit. One end of the fifth resistor R5 is connected to the MCU and is primarily used to limit the discharge signal current, preventing excessive current from directly impacting the gate of the second MOS transistor Q1 and damaging it. At the same time, it effectively transmits the discharge signal to the gate of the second MOS transistor Q1 to control the on and off states of the second MOS transistor Q1; the gate of the second MOS transistor Q1 is connected to the other end of the fifth resistor R5, the source of the second MOS transistor Q1 is grounded, the drain of the second MOS transistor Q1 is connected to one end of the bidirectional breakdown diode Z2, and the terminal 2 of the isolation drive transformer TR3, and the on and off of the circuit are controlled according to the discharge control signal. When the discharge control signal turns on the second MOS transistor Q1, it allows current to flow from the drain to the source, thereby realizing the conduction of the energy transmission path; the terminal 1 of the isolation drive transformer TR3 is connected to one end of the bidirectional breakdown diode Z2 and then to the VCC port, the terminal 3 of the isolation drive transformer TR3 is connected to one end of the sixth resistor R7, and the isolation drive transformer Terminal 4 of TR3 is grounded; the other end of the sixth resistor R7 is connected to the anode of the second diode D3, limiting the current of the signal output from the isolation drive transformer TR3 to prevent excessive current from damaging the second diode D3 and subsequent components. At the same time, it effectively transmits the signal transformed by the isolation drive transformer TR3 to the second diode D3, ensuring smooth signal transmission within the circuit; the cathode of the second diode D3 is connected to the gate of the thyristor T2; the cathode of the thyristor T2 is grounded, and the anode of the thyristor T2 is connected to terminal 2 of the high-frequency inductor TR2. When the discharge current in the primary of the high-frequency inductor TR2 falls below a threshold, the thyristor T2 automatically turns off to ensure only one discharge within a cycle, awaiting the arrival of the next charging cycle; a hardware protection circuit is connected to the gate and anode of the thyristor T2.

[0048] Further, specifically, Figure 1As shown, the hardware protection circuit comprises: a Zener Z1 and a seventh resistor R8; one end of the Zener Z1 is connected to the anode of the thyristor T2; one end of the seventh resistor R8 is connected to one end of the Zener Z1, and the other end of the seventh resistor R8 is connected between the gate of the thyristor T2 and the negative electrode of the second diode D3. The hardware protection circuit is used to forcibly open T2 when the voltage on the capacitor exceeds the value of the Zener Z1, preventing the voltage from accumulating too high when the MCU control is wrong, and damaging the components.

[0049] Further, as shown in the figure, Figure 1 the discharge control circuit further comprises: a third diode D2, the negative electrode of the third diode D2 is connected between the sixth resistor R7 and the second diode D3, and the other end of the third diode D2 is grounded. The third diode D2 plays a clamping role, and when there is a too high positive voltage spike in the circuit, for example, a transient voltage generated during switching, the third diode D2 clamps the voltage at a lower level, protecting the second diode D3 and other subsequent components from damage from excessive voltage.

[0050] Further, as shown in the figure, Figure 1 the discharge control circuit further comprises: an eighth resistor R9 and a fifth capacitor C5; one end of the eighth resistor R9 is connected between the gate of the thyristor T2 and the negative electrode of the second diode D3, and the other end of the eighth resistor R9 is grounded; one end of the fifth capacitor C5 is connected between one end of the eighth resistor R9 and the gate of the thyristor T2, and the other end of the fifth capacitor C5 is grounded. The eighth resistor R9 and the fifth capacitor C5 are used for anti-interference and filtering.

[0051] Further, as shown in the figure, Figure 1 the discharge control circuit further comprises: a ninth resistor R6, one end of the ninth resistor R6 is connected between the other end of the fifth resistor R5 and the gate of the second MOS Q1, and the other end of the ninth resistor R6 is connected to the source of the second MOS Q1 and then grounded. The ninth resistor R6 provides a discharge path between the gate and the source of the second MOS Q1, which can quickly discharge the charge on the gate when the gate signal disappears, so that the second MOS Q1 can be reliably turned off. In addition, it can also form a voltage dividing circuit with the fifth resistor R5 to adjust the voltage at the gate of the second MOS Q1 to a certain extent, ensuring that the second MOS Q1 can be turned on and off according to the expected voltage threshold.

[0052] Specifically, as shown in the figure, Figure 1 terminal 1 of the high-frequency inductor TR2 is connected to the charging control circuit, terminal 2 of the high-frequency inductor TR2 is connected to the discharge control circuit, and terminals 3 and 4 of the high-frequency inductor TR2 are connected to the external electric welding machine output main circuit.

[0053] The charging control signal is a group of pulse signals, which is sent by the single-chip microcomputer, and the period (or frequency) of the charging is the frequency of the high frequency;

[0054] The discharging control signal is sent after the charging control signal, and the fixed time is determined by the desired strength of the high frequency.

[0055] For example:

[0056] When we first use the argon arc welding machine, the tungsten needle is cold at this time, and a higher success rate of arc striking is required at this time, and the high frequency performance is strong;

[0057] At this time, the charging control signal frequency can be set to 100Hz, that is, a period of 10ms, and after a period of charging, the voltage on the second capacitor C4 continuously rises, and at this time, the discharging control signal is sent, for example, after 25us of charging;

[0058] Immediately start discharging, at this time the voltage on the second capacitor C4 is about 1200V, after the high frequency inductor TR2, and after the voltage is boosted again, it is provided to the output main circuit of the electric welding machine.

[0059] After the machine is used for a short time, the tungsten needle is already relatively high in heat, and at this time, a stable arc striking voltage is not required, and at this time, the discharging can be started after 15us of charging, and at this time, the voltage on the second capacitor C4 is about 750V.

[0060] In this way, we can achieve different discharging voltages through time control.

[0061] When different arc striking frequencies are required, the charging control signal frequency can be changed.

[0062] The above, with reference to Figure 1 The intelligent high-frequency arc striking circuit according to the embodiment of the present application is described, the frequency and voltage control of the high-frequency high-voltage arc striking circuit can be adjusted, different working frequencies and working voltages are selected according to different use cases, and the high-frequency interference can be effectively reduced, and the radiation damage to the human body can be reduced.

[0063] It should be noted that in the present specification, the terms “include”, “contain” or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the elements defined by the statement “contain” do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0064] While the application has been described in detail by reference to preferred embodiments thereof, it should be recognized that the description set forth herein is by way of example and that modifications of the procedures described can be employed without departing from the scope of the application. Accordingly, the scope of the application should be determined by the appended claims and equivalents thereof.

Claims

1. An intelligent high-frequency arc ignition circuit, characterized in that: Includes: MCU, charging control circuit, discharge control circuit and high-frequency inductor; The MCU is used to send charging control signals and discharging control signals; The charging control circuit is connected to the MCU and is used to receive and process the charging control signal; The discharge control circuit is connected to the MCU and is used to receive and process the discharge control signal; Terminal 1 of the high-frequency inductor is connected to the charging control circuit, terminal 2 of the high-frequency inductor is connected to the discharging control circuit, and terminals 3 and 4 of the high-frequency inductor are connected to the external welding machine output main circuit; The charging control circuit includes: a boost control chip, a first resistor, a first MOS tube, a second resistor, a third resistor, a first capacitor, a boost transformer, a first diode and a second capacitor; Pin 1 of the boost control chip is connected to the MCU, pin 6 of the boost control chip is connected to one end of the first resistor, and pin 3 of the boost control chip is connected to one end of the second resistor; The other end of the first resistor is connected to the gate of the first MOS transistor; The other end of the second resistor is connected to the source of the first MOS transistor and one end of the third resistor; The other end of the third resistor is grounded; The drain of the first MOS transistor is connected to the terminal 1 of the boost transformer; After the terminal 2 of the step-up transformer is connected to the VCC port and grounded through the first capacitor, the terminal HV of the step-up transformer is connected to the positive electrode of the first diode; The cathode of the first diode is connected to terminal 1 of the high-frequency inductor and one end of the second capacitor; The other end of the second capacitor is connected to the terminal 3 of the step-up transformer and then grounded; The discharge control circuit includes: a fifth resistor, a second MOS tube, a bidirectional breakdown diode, an isolation drive transformer, a sixth resistor, a second diode, a thyristor and a hardware protection circuit; One end of the fifth resistor is connected to the MCU; The gate of the second MOS transistor is connected to the other end of the fifth resistor, the source of the second MOS transistor is grounded, and the drain of the second MOS transistor is connected to one end of the bidirectional breakdown diode and the terminal 2 of the isolation drive transformer; The terminal 1 of the isolation drive transformer is connected to one end of the bidirectional breakdown diode and then to the VCC port, the terminal 3 of the isolation drive transformer is connected to one end of the sixth resistor, and the terminal 4 of the isolation drive transformer is grounded; The other end of the sixth resistor is connected to the anode of the second diode; The cathode of the second diode is connected to the gate of the thyristor; The cathode of the thyristor is grounded, and the anode of the thyristor is connected to the terminal 2 of the high-frequency inductor; The hardware protection circuit is connected to the gate and anode of the thyristor.

2. The intelligent high-frequency arc ignition circuit according to claim 1, characterized in that: The charging control circuit further includes: a third capacitor, one end of the third capacitor is connected between pin 3 of the boost control chip and one end of the second resistor, and the other end of the third capacitor is grounded.

3. The intelligent high-frequency arc ignition circuit according to claim 1, characterized in that: The charging control circuit further comprises: a fourth resistor and a fourth capacitor; One end of the fourth resistor is connected to pin 8 of the boost control chip; One end of the fourth capacitor is connected to the pin 4 of the boost control chip and the other end of the fourth resistor, and the other end of the fourth capacitor is grounded.

4. The intelligent high-frequency arc ignition circuit according to claim 1, characterized in that: The hardware protection circuit includes: a voltage regulator tube and a seventh resistor; One end of the voltage regulator tube is connected to the anode of the thyristor; One end of the seventh resistor is connected to one end of the voltage regulator tube, and the other end of the seventh resistor is connected between the gate of the thyristor and the cathode of the second diode.

5. The intelligent high-frequency arc ignition circuit according to claim 1, characterized in that: The discharge control circuit further includes: a third diode, wherein a cathode of the third diode is connected between the sixth resistor and the second diode, and the other end of the third diode is grounded.

6. The intelligent high-frequency arc ignition circuit according to claim 1, characterized in that: The discharge control circuit further comprises: an eighth resistor and a fifth capacitor; One end of the eighth resistor is connected between the gate of the thyristor and the cathode of the second diode, and the other end of the eighth resistor is grounded; One end of the fifth capacitor is connected between one end of the eighth resistor and the gate of the thyristor, and the other end of the fifth capacitor is grounded.

7. The intelligent high-frequency arc ignition circuit according to claim 1, characterized in that: The discharge control circuit further includes: a ninth resistor, one end of the ninth resistor is connected between the other end of the fifth resistor and the gate of the second MOS transistor, and the other end of the ninth resistor is connected to the source of the second MOS transistor and then grounded.

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