Control circuit, control device and electric welding machine

Abstract

The utility model discloses a control circuit, a control device and an electric welding machine, and relates to the technical field of electric welding machine control. The control circuit is applied to the electric welding machine, the electric welding machine comprises a power input end and a power output end, and the control circuit comprises a main control circuit; the driving circuit is used for converting the control signal output by the main control circuit into a driving signal and outputting the driving signal; the voltage conversion circuit is used for converting a first voltage input by the power supply input end into a second voltage and outputting the second voltage; the switching circuit is used for connecting or disconnecting a path between the power supply input end and the power supply output end according to the driving signal; the sampling circuit is used for collecting a first signal and outputting the first signal to the main control circuit; wherein the main control circuit is used for outputting a control signal to the driving circuit according to the first signal. The utility model aims to solve the problems of welding rod adhesion and device damage during welding of the electric welding machine.

Description

Technical Field

[0001] The utility model relates to the technical field of electric welding machine control, in particular to a control circuit, a control device and an electric welding machine. Background Art

[0002] In the field of electric welding machines, manual arc welding requires welding rods for welding. When starting an arc, a large output current is usually required to ignite the welding rod, thereby entering a normal welding state. When the arc is not started successfully, if a large current continues to be output, the welding rod is easy to stick to the workpiece, resulting in the inability to perform welding operations again. The arc starting anti-sticking function is to actively reduce the output current when it is detected that the welding rod is in contact with the workpiece (the output voltage is usually less than 10V) for a period of time to prevent the welding rod from sticking to the workpiece. In the prior art, it is usually necessary to collect the output voltage of the welding machine through the output voltage detection circuit. When the output voltage is continuously lower than a certain voltage value, the PWM pulse width is adjusted through the PWM control circuit to actively reduce the output current of the welding machine from the short-circuit current to the small current output to prevent the welding rod from sticking to the workpiece. However, this method will bring two problems: the output current of the welding machine is actively reduced from the short-circuit current to the small current output. With a small current, the thin welding rod will still have sticking strips; when the output rectifier device is short-circuited, the PWM controls the narrow pulse width output, and the switching device is at risk of damage. Utility Model Content

[0003] The main purpose of the utility model is to provide a control circuit, aiming to solve the problem of welding rod adhesion and device damage during welding with an electric welder.

[0004] To achieve the above object, the control circuit proposed in the utility model, the electric welding machine includes a power input end and a power output end, and the control circuit includes:

[0005] Main control circuit;

[0006] A drive circuit, wherein an input end of the drive circuit is electrically connected to the main control circuit, and the drive circuit is used to convert a control signal output by the main control circuit into a drive signal and output the drive signal;

[0007] A voltage conversion circuit, wherein the input terminals of the voltage conversion circuit are electrically connected to the power input terminals respectively, and the voltage conversion circuit is used to convert a first voltage input from the power input terminal into a second voltage and output the second voltage;

[0008] a switch circuit, wherein an input end of the switch circuit is electrically connected to the voltage conversion circuit, a controlled end of the switch circuit is electrically connected to the drive circuit, an output end of the switch circuit is electrically connected to the output end, and the switch circuit is used to open or close a path between the power input end and the power output end according to the drive signal;

[0009] A sampling circuit, wherein an output end of the sampling circuit is electrically connected to the main control circuit, and the sampling circuit is used to collect a first signal and output the first signal to the main control circuit;

[0010] Wherein, the main control circuit is used to output a control signal to the driving circuit according to the first signal.

[0011] In one embodiment, the driving circuit includes a driving transformer, a first resistor, and a first capacitor; and the driving transformer includes a primary coil, a first secondary coil, and a second secondary coil;

[0012] Among them, the first end of the first resistor is electrically connected to the first end of the first capacitor and the main control circuit, the second end of the first resistor is electrically connected to the second end of the first capacitor and the second end of the primary coil; the first end of the primary coil is electrically connected to the main control circuit; the first secondary coil and the second secondary coil are electrically connected to the switching circuit respectively.

[0013] In one embodiment, the voltage conversion circuit includes:

[0014] An input rectifier circuit, wherein an input terminal of the input rectifier circuit is electrically connected to the power input terminal, and the input rectifier circuit is used to rectify an input first voltage into a DC voltage and output the DC voltage;

[0015] A filter circuit, the filter circuit is electrically connected to the output end of the input rectifier circuit, the filter circuit is electrically connected to the input end of the switch circuit, and the filter circuit is used for output filtering of the input rectifier circuit;

[0016] A transformer, wherein the primary coil of the transformer is electrically connected to the output end of the switch circuit, and the transformer is used to output the voltage output by the switch circuit after voltage conversion;

[0017] An output rectifier circuit, wherein the input end of the output rectifier circuit is electrically connected to the secondary coil of the transformer, the output end of the output rectifier circuit is electrically connected to the output end of the power supply, and the output rectifier circuit rectifies the input AC voltage into a second voltage and outputs it.

[0018] In one embodiment, the voltage conversion circuit further includes a first diode, a second diode, a third diode, a fourth diode, a second capacitor, a third capacitor, and a fourth capacitor;

[0019] Among them, the anode of the first diode is electrically connected to the first end of the power input terminal, and the cathode is electrically connected to the first end of the second capacitor, the first end of the third capacitor, and the cathode of the second diode; the anode of the second diode is electrically connected to the second end of the power input terminal and the cathode of the third diode; the anode of the third diode is electrically connected to the second end of the second capacitor, the second end of the fourth capacitor, and the anode of the fourth diode; the cathode of the fourth diode is electrically connected to the anode of the first diode; the second end of the third capacitor is electrically connected to the first end of the fourth capacitor.

[0020] In one embodiment, the switch circuit includes a second resistor, a third resistor, a first switch tube, and a second switch tube;

[0021] Among them, the first end of the second resistor is electrically connected to the second end of the first secondary coil, and the second end is electrically connected to the controlled end of the first switch tube; the first end of the third resistor is electrically connected to the second end of the second secondary coil, and the second end is electrically connected to the controlled end of the second switch tube; the first end of the first switch tube is electrically connected to the first end of the first secondary coil and the second end of the fourth capacitor, and the second end is electrically connected to the first end of the second secondary coil and the second end of the primary coil of the transformer; the first end of the second switch tube is electrically connected to the second end of the first switch tube, and the second end is electrically connected to the first end of the third capacitor.

[0022] In one embodiment, the sampling circuit includes a current sampling circuit and a voltage sampling circuit;

[0023] Wherein, the input end of the current sampling circuit is electrically connected to the voltage conversion circuit, the output end of the current sampling circuit is electrically connected to the main control circuit, and the current sampling circuit is used to obtain and output a current sampling signal;

[0024] The input end of the current sampling circuit is electrically connected to the output end of the power supply, the output end of the current sampling circuit is electrically connected to the main control circuit, and the current sampling circuit is used to obtain and output a current sampling signal.

[0025] In one embodiment, the current sampling circuit includes a current transformer, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a TVS tube, and a fourth resistor;

[0026] Among them, the first end of the primary coil of the current transformer is electrically connected to the second end of the second capacitor, and the second end is electrically connected to the transformer; the first end of the secondary coil of the current transformer is electrically connected to the anode of the fifth diode and the cathode of the sixth diode; the second end of the secondary coil of the current transformer is electrically connected to the anode of the seventh diode and the cathode of the eighth diode; the cathode of the fifth diode, the cathode of the seventh diode, the first end of the fourth resistor, and the cathode of the TVS tube are electrically connected to the input end of the main control circuit; the anode of the sixth diode, the anode of the eighth diode, the second end of the fourth resistor, and the anode of the TVS tube are electrically connected to the ground terminal.

[0027] In one embodiment, the voltage sampling circuit includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a voltage stabilizing diode, a ninth diode, a fifth capacitor, and an optical coupler;

[0028] Among them, the anode of the voltage-stabilizing diode is electrically connected to the negative electrode of the power output end, and the cathode is electrically connected to the second end of the sixth resistor; the first end of the sixth resistor is electrically connected to the second end of the primary side of the optocoupler; the second end of the eighth resistor is electrically connected to the positive electrode of the power output end, and the second end is electrically connected to the cathode of the ninth diode; the anode of the ninth diode is electrically connected to the second end of the seventh resistor and the first end of the primary side of the optocoupler; the first end of the seventh resistor is electrically connected to the power supply end; the first end of the secondary side of the optocoupler is electrically connected to the main control circuit and the power supply end of the main control circuit; the second end of the secondary side of the optocoupler is electrically connected to the first end of the fifth capacitor, the first end of the fifth resistor, and the main control circuit; the second end of the fifth capacitor and the second end of the fifth resistor are electrically connected to the ground end.

[0029] The utility model also provides a control device, which includes a control circuit as described in any one of the above items.

[0030] The utility model also provides an electric welding machine, which comprises the control circuit as described in any one of the above or the control device as described in the above.

[0031] The technical solution of the utility model effectively solves the problem of welding rod adhesion and device damage during welding by an electric welder by adopting a control circuit. Among them, the control circuit monitors the output current of the electric welder through a sampling circuit, and feeds back to the main control circuit, so that the main control circuit controls the drive circuit to output a drive signal to the switch circuit, so that the switch circuit increases the output current to a specific short-circuit current. At this time, the sampling circuit will also monitor the output voltage of the electric welder in real time, and output a voltage acquisition signal to the main control circuit, so that the main control circuit determines whether the current state is a normal working state. When the voltage acquisition signal output by the sampling circuit is judged to be a low voltage, the main control circuit controls the switch circuit to disconnect the path between the power input terminal and the power output terminal, thereby achieving the technical effect of preventing welding rods from sticking under no current. When the output rectifier device is short-circuited, the output voltage is collected, and the PWM output is stopped when the output rectifier device is short-circuited, effectively preventing the switch device from being damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 It is a module schematic diagram of the control circuit of the utility model;

[0034] Figure 2 This is a module schematic diagram of an embodiment of the control circuit of the utility model;

[0035] Figure 3 It is a structural schematic diagram of the control circuit of the utility model.

[0036] Description of Figure Numbers:

[0037] 10. Main control circuit; 20. Driving circuit; 30. Voltage conversion circuit; 40. Switching circuit; 50. Sampling circuit; 51. Voltage sampling circuit; 52. Current sampling circuit; R1-R8, first resistor-eighth resistor; C1-C4, first capacitor-fourth capacitor; D1-D8, first diode-eighth diode.

[0038] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0040] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0041] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0042] In the field of electric welding machines, manual arc welding requires welding rods for welding. When starting an arc, a large output current is usually required to ignite the welding rod, thereby entering a normal welding state. When the arc is not started successfully, if a large current continues to be output, the welding rod is easy to stick to the workpiece, resulting in the inability to perform welding operations again. The arc starting anti-sticking function is to actively reduce the output current when it detects that the welding rod is in contact with the workpiece (the output voltage is usually less than 10V) for a period of time to prevent the welding rod from sticking to the workpiece. In the prior art, it is usually necessary to collect the output voltage of the welding machine through the output voltage detection circuit. When the output voltage is continuously lower than a certain voltage value, the PWM control circuit is used to adjust the PWM pulse width so that the output current of the welding machine is actively reduced from the short-circuit current to the small current output to prevent the welding rod from sticking to the workpiece. However, this method will bring two problems: the output current of the welding machine is actively reduced from the short-circuit current to the small current output. With a small current, the thin welding rod will still stick; when the output rectifier device is short-circuited, the PWM controls the narrow pulse width output, and the switching device is at risk of damage.

[0043] Therefore, reference Figures 1 to 3 The utility model provides a control circuit, which is applied to an electric welding machine. The electric welding machine includes a power input terminal and a power output terminal. The control circuit includes:

[0044] Main control circuit 10;

[0045] A drive circuit 20, wherein an input end of the drive circuit 20 is electrically connected to the main control circuit 10, and the drive circuit 20 is used to convert a control signal output by the main control circuit 10 into a drive signal and output the drive signal;

[0046] A voltage conversion circuit 30, wherein the input terminals of the voltage conversion circuit 30 are electrically connected to the power input terminals respectively, and the voltage conversion circuit 30 is used to convert a first voltage input from the power input terminal into a second voltage and output the second voltage;

[0047] a switch circuit 40, wherein the input end of the switch circuit 40 is electrically connected to the voltage conversion circuit 30, the controlled end of the switch circuit 40 is electrically connected to the drive circuit 20, the output end of the switch circuit 40 is electrically connected to the output end, and the switch circuit 40 is used to open or close the path between the power input end and the power output end according to the drive signal;

[0048] A sampling circuit 50, wherein an output end of the sampling circuit 50 is electrically connected to the main control circuit 10, and the sampling circuit 50 is used to collect a first signal and output the first signal to the main control circuit 10;

[0049] The main control circuit 10 is used for outputting a control signal to the driving circuit 20 according to the first signal.

[0050] In this embodiment, the main control circuit 10 can be implemented by a main controller, for example, a PLC (Programmable Logic Controller), an MCU (Microcontroller Unit), a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), a SOC (System On Chip), etc. The main control circuit 10 outputs a corresponding control signal to the drive circuit 20 by acquiring the first signal output by the sampling circuit 50, so that the drive circuit 20 outputs a drive signal to the switch circuit 40, thereby causing the switch circuit 40 to perform a corresponding action. Specifically, the main control circuit 10 determines the state of the current circuit by acquiring the first signal output by the sampling circuit 50, and outputs a corresponding PWM control signal to the drive circuit 20, which is then output to the switch circuit 40 via the drive circuit 20, thereby controlling the switch circuit 40 to turn off. The main control circuit 10 controls the output voltage by controlling the turn-off frequency of the switch circuit 40.

[0051] In this embodiment, the driving circuit 20 includes a driving transformer, a first resistor R1, and a first capacitor C1; and the driving transformer includes a primary coil, a first secondary coil, and a second secondary coil; wherein the first end of the first resistor R1 is electrically connected to the first end of the first capacitor C1 and the main control circuit 10, and the second end of the first resistor R1 is electrically connected to the second end of the first capacitor C1 and the second end of the primary coil; the first end of the primary coil is electrically connected to the main control circuit 10; the first secondary coil and the second secondary coil are electrically connected to the switch circuit 40, respectively. Specifically, the main control circuit 10 outputs a PWM control signal that is filtered by the first resistor R1 and the first capacitor C1, and the driving transformer converts the PWM control signal into two sets of driving signals, which are respectively output to the switch circuit 40 by the first secondary coil and the second secondary coil, so that the switch device in the switch circuit 40 performs a corresponding action when receiving the driving signal.

[0052] In this embodiment, the voltage conversion circuit 30 includes:

[0053] An input rectifier circuit, wherein an input terminal of the input rectifier circuit is electrically connected to the power input terminal, and the input rectifier circuit is used to rectify an input first voltage into a DC voltage and output the DC voltage;

[0054] A filter circuit, the filter circuit is electrically connected to the output end of the input rectifier circuit, the filter circuit is electrically connected to the input end of the switch circuit 40, and the filter circuit is used for output filtering of the input rectifier circuit;

[0055] A transformer, wherein the primary coil of the transformer is electrically connected to the output end of the switch circuit 40, and the transformer is used to output the voltage output by the switch circuit 40 after voltage conversion;

[0056] An output rectifier circuit, wherein the input end of the output rectifier circuit is electrically connected to the secondary coil of the transformer, the output end of the output rectifier circuit is electrically connected to the output end of the power supply, and the output rectifier circuit rectifies the input AC voltage into a second voltage and outputs it.

[0057] Furthermore, the voltage conversion circuit 30 also includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4; wherein, the anode of the first diode D1 is electrically connected to the first end of the power input end, and the cathode is electrically connected to the first end of the second capacitor C2, the first end of the third capacitor C3, and the cathode of the second diode D2; the anode of the second diode D2 is electrically connected to the second end of the power input end and the cathode of the third diode D3; the anode of the third diode D3 is electrically connected to the second end of the second capacitor C2, the second end of the fourth capacitor C4, and the anode of the fourth diode D4; the cathode of the fourth diode D4 is electrically connected to the anode of the first diode D1; the second end of the third capacitor C3 is electrically connected to the first end of the fourth capacitor C4.

[0058] It can be understood that in this embodiment, the input rectifier circuit is a bridge rectifier circuit. In addition, the input rectifier circuit can also be implemented by a full-wave rectifier circuit, a half-wave rectifier circuit, etc. Among them, the power input terminal is connected to the mains 220V AC voltage (i.e., the first voltage), which is then rectified by the bridge rectifier circuit and output to the filter circuit, and filtered by the filter circuit to output a DC voltage of about 310V to the switch circuit 40. Among them, the switch circuit 40 turns on or off the path between the power input terminal and the power output terminal according to the drive signal output by the drive circuit 20, so that the DC voltage output by the filter circuit is inverted into an AC square wave voltage of about 155V. It should be understood that the sampling circuit 50 here includes a current sampling circuit 52 using a current transformer. Among them, the AC voltage inverted and output by the switch circuit 40 is then output by the transformer as an AC square wave voltage of about 60V. The electric welding method used in this embodiment is DC electric welding, so it is necessary to rectify and output the AC square wave voltage of about 60V to facilitate the welding work. Specifically, the output rectification circuit can be implemented by a bridge rectification circuit, a full-wave rectification circuit, a half-wave rectification circuit, etc. In this embodiment, two groups of parallel-connected diodes are used as the output rectification circuit, thereby implementing half-wave rectification.

[0059] In this embodiment, the switch circuit 40 includes a second resistor R2, a third resistor R3, a first switch tube, and a second switch tube; wherein the first end of the second resistor R2 is electrically connected to the second end of the first secondary coil, and the second end is electrically connected to the controlled end of the first switch tube; the first end of the third resistor R3 is electrically connected to the second end of the second secondary coil, and the second end is electrically connected to the controlled end of the second switch tube; the first end of the first switch tube is electrically connected to the first end of the first secondary coil and the second end of the fourth capacitor C4, and the second end is electrically connected to the first end of the second secondary coil and the second end of the primary coil of the transformer; the first end of the second switch tube is electrically connected to the second end of the first switch tube, and the second end is electrically connected to the first end of the third capacitor C3. Further, the first switch tube and the second switch tube can be implemented by, for example, MOS tube, IGBT tube, thyristor, triode, power tube, etc. The controlled end of the first switch tube and the controlled end of the second switch tube are respectively connected to the first secondary coil and the second secondary coil of the driving transformer, so as to obtain the driving signal, and the switching frequency of the first switch tube and the second switch tube is controlled by the PWM signal output by the main control circuit 10, and the switching state of the first switch tube and the second switch tube is controlled by the first secondary coil and the second secondary coil. Thus, the technical effect of the inversion of the switch circuit 40 and the technical effect of the shutdown circuit are achieved.

[0060] In this embodiment, the sampling circuit 50 includes a current sampling circuit 52 and a voltage sampling circuit 51;

[0061] The input end of the current sampling circuit 52 is electrically connected to the voltage conversion circuit 30, the output end of the current sampling circuit 52 is electrically connected to the main control circuit 10, and the current sampling circuit 52 is used to obtain and output a current sampling signal;

[0062] The input end of the current sampling circuit 52 is electrically connected to the output end of the power supply, and the output end of the current sampling circuit 52 is electrically connected to the main control circuit 10. The current sampling circuit 52 is used to obtain and output a current sampling signal.

[0063] Furthermore, the current sampling circuit 52 includes a current transformer, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, a TVS tube, and a fourth resistor R4;

[0064] Among them, the first end of the primary coil of the current transformer is electrically connected to the second end of the second capacitor C2, and the second end is electrically connected to the transformer; the first end of the secondary coil of the current transformer is electrically connected to the anode of the fifth diode D5 and the cathode of the sixth diode D6; the second end of the secondary coil of the current transformer is electrically connected to the anode of the seventh diode D7 and the cathode of the eighth diode D8; the cathode of the fifth diode D5, the cathode of the seventh diode D7, the first end of the fourth resistor R4, and the cathode of the TVS tube are electrically connected to the input end of the main control circuit 10; the anode of the sixth diode D6, the anode of the eighth diode D8, the second end of the fourth resistor R4, and the anode of the TVS tube are electrically connected to the ground terminal.

[0065] The voltage sampling circuit 51 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a voltage stabilizing diode, a ninth diode, a fifth capacitor, and an optical coupler;

[0066] Among them, the anode of the voltage-stabilizing diode is electrically connected to the negative electrode of the power output end, and the cathode is electrically connected to the second end of the sixth resistor R6; the first end of the sixth resistor R6 is electrically connected to the second end of the primary side of the optocoupler; the second end of the eighth resistor R8 is electrically connected to the positive electrode of the power output end, and the second end is electrically connected to the cathode of the ninth diode; the anode of the ninth diode is electrically connected to the second end of the seventh resistor R7 and the first end of the primary side of the optocoupler; the first end of the seventh resistor R7 is electrically connected to the power supply end; the first end of the secondary side of the optocoupler is electrically connected to the main control circuit 10 and the power supply end of the main control circuit 10; the second end of the secondary side of the optocoupler is electrically connected to the first end of the fifth capacitor, the first end of the fifth resistor R5, and the main control circuit 10; the second end of the fifth capacitor and the second end of the fifth resistor R5 are electrically connected to the ground end.

[0067] In this embodiment, the current sampling circuit 52 obtains the current through a 200:1 current transformer to sample the current, and rectifies the current through multiple diodes and outputs it to the main control circuit 10. In addition, the current sampling circuit 52 can also be implemented by using sensors such as a resistor shunt, a Hall current sensor, a Rogowski coil current sensor, a fluxgate current sensor, and an optical fiber current sensor. Among them, the current sampling circuit also clamps the voltage through a voltage regulator diode to ensure that the voltage in the current sampling circuit 52 does not exceed its safe working range.

[0068] In this embodiment, the voltage sampling circuit 51 can be implemented by a resistor voltage-dividing sampling circuit, a linear operational amplifier voltage sampling circuit, a voltage sampling transformer, etc. Specifically, when the power output terminal is short-circuited, the potential of the first terminal of the optical coupler will be pulled down by the ninth diode, so that the voltage-stabilizing diode cannot be broken down, and thus no current flows through the primary side of the optical coupler. At this time, the secondary coil of the optical coupler is in a high-resistance state, and the voltage acquisition signal received by the main control circuit 10 is a low-level signal, thereby stopping the output of the PWM signal, so that the switch circuit 40 disconnects the path between the power input terminal and the power output terminal.

[0069] The control circuit monitors the output current of the electric welding machine through the sampling circuit 50, and feeds back to the main control circuit 10, so that the main control circuit 10 controls the drive circuit 20 to output a drive signal to the switch circuit 40, so that the switch circuit 40 increases the output current to a specific short-circuit current. At this time, the sampling circuit 50 will also monitor the output voltage of the electric welding machine in real time, and output a voltage acquisition signal to the main control circuit 10, so that the main control circuit 10 determines whether the current state is a normal working state. When the voltage acquisition signal output by the sampling circuit 50 is judged to be a low voltage, the main control circuit 10 controls the switch circuit 40 to disconnect the path between the power input terminal and the power output terminal, thereby achieving the technical effect of preventing the welding rod from sticking under no current. When the output rectifier device is short-circuited, the output voltage is collected, and the PWM output is stopped when the output rectifier device is short-circuited, effectively preventing the switch device from being damaged.

[0070] The utility model also proposes a control device, the control device comprising any one of the control circuits described above. It is worth noting that since the control device of the utility model is based on the control circuit described above, the embodiments of the control device of the utility model include all technical solutions of all embodiments of the control circuit described above, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0071] The utility model also proposes an electric welding machine, the electric welding machine comprising any one of the control circuits or the control devices as described above. It is worth noting that since the electric welding machine of the utility model is based on the control circuit or the control device as described above, the embodiments of the electric welding machine of the utility model include all technical solutions of all embodiments of the control circuit or the control device as described above, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0072] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A control circuit, applied to an electric welding machine, characterized in that: The electric welder comprises a power input terminal and a power output terminal, and the control circuit comprises: Main control circuit; A drive circuit, wherein an input end of the drive circuit is electrically connected to the main control circuit, and the drive circuit is used to convert a control signal output by the main control circuit into a drive signal and output the drive signal; A voltage conversion circuit, wherein the input terminals of the voltage conversion circuit are electrically connected to the power input terminals respectively, and the voltage conversion circuit is used to convert a first voltage input from the power input terminal into a second voltage and output the second voltage; a switch circuit, wherein an input end of the switch circuit is electrically connected to the voltage conversion circuit, a controlled end of the switch circuit is electrically connected to the drive circuit, an output end of the switch circuit is electrically connected to the output end, and the switch circuit is used to open or close a path between the power input end and the power output end according to the drive signal; A sampling circuit, wherein an output end of the sampling circuit is electrically connected to the main control circuit, and the sampling circuit is used to collect a first signal and output the first signal to the main control circuit; Wherein, the main control circuit is used to output a control signal to the driving circuit according to the first signal.

2. The control circuit according to claim 1, characterized in that: The driving circuit includes a driving transformer, a first resistor, and a first capacitor; and the driving transformer includes a primary coil, a first secondary coil, and a second secondary coil; Among them, the first end of the first resistor is electrically connected to the first end of the first capacitor and the main control circuit, the second end of the first resistor is electrically connected to the second end of the first capacitor and the second end of the primary coil; the first end of the primary coil is electrically connected to the main control circuit; the first secondary coil and the second secondary coil are electrically connected to the switching circuit respectively.

3. The control circuit according to claim 2, characterized in that: The voltage conversion circuit comprises: An input rectifier circuit, wherein an input terminal of the input rectifier circuit is electrically connected to the power input terminal, and the input rectifier circuit is used to rectify an input first voltage into a DC voltage and output the DC voltage; A filter circuit, the filter circuit is electrically connected to the output end of the input rectifier circuit, the filter circuit is electrically connected to the input end of the switch circuit, and the filter circuit is used for output filtering of the input rectifier circuit; A transformer, wherein the primary coil of the transformer is electrically connected to the output end of the switch circuit, and the transformer is used to output the voltage output by the switch circuit after voltage conversion; An output rectifier circuit, wherein the input end of the output rectifier circuit is electrically connected to the secondary coil of the transformer, the output end of the output rectifier circuit is electrically connected to the output end of the power supply, and the output rectifier circuit rectifies the input AC voltage into a second voltage and outputs it.

4. The control circuit according to claim 3, characterized in that: The voltage conversion circuit also includes a first diode, a second diode, a third diode, a fourth diode, a second capacitor, a third capacitor, and a fourth capacitor; Among them, the anode of the first diode is electrically connected to the first end of the power input terminal, and the cathode is electrically connected to the first end of the second capacitor, the first end of the third capacitor, and the cathode of the second diode; the anode of the second diode is electrically connected to the second end of the power input terminal and the cathode of the third diode; the anode of the third diode is electrically connected to the second end of the second capacitor, the second end of the fourth capacitor, and the anode of the fourth diode; the cathode of the fourth diode is electrically connected to the anode of the first diode; the second end of the third capacitor is electrically connected to the first end of the fourth capacitor.

5. The control circuit according to claim 4, characterized in that: The switch circuit includes a second resistor, a third resistor, a first switch tube, and a second switch tube; Among them, the first end of the second resistor is electrically connected to the second end of the first secondary coil, and the second end is electrically connected to the controlled end of the first switch tube; the first end of the third resistor is electrically connected to the second end of the second secondary coil, and the second end is electrically connected to the controlled end of the second switch tube; the first end of the first switch tube is electrically connected to the first end of the first secondary coil and the second end of the fourth capacitor, and the second end is electrically connected to the first end of the second secondary coil and the second end of the primary coil of the transformer; the first end of the second switch tube is electrically connected to the second end of the first switch tube, and the second end is electrically connected to the first end of the third capacitor.

6. The control circuit according to claim 5, characterized in that: The sampling circuit includes a current sampling circuit and a voltage sampling circuit; Wherein, the input end of the current sampling circuit is electrically connected to the voltage conversion circuit, the output end of the current sampling circuit is electrically connected to the main control circuit, and the current sampling circuit is used to obtain and output a current sampling signal; The input end of the current sampling circuit is electrically connected to the output end of the power supply, the output end of the current sampling circuit is electrically connected to the main control circuit, and the current sampling circuit is used to obtain and output a current sampling signal.

7. The control circuit according to claim 6, characterized in that: The current sampling circuit includes a current transformer, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a TVS tube, and a fourth resistor; Among them, the first end of the primary coil of the current transformer is electrically connected to the second end of the second capacitor, and the second end is electrically connected to the transformer; the first end of the secondary coil of the current transformer is electrically connected to the anode of the fifth diode and the cathode of the sixth diode; the second end of the secondary coil of the current transformer is electrically connected to the anode of the seventh diode and the cathode of the eighth diode; the cathode of the fifth diode, the cathode of the seventh diode, the first end of the fourth resistor, and the cathode of the TVS tube are electrically connected to the input end of the main control circuit; the anode of the sixth diode, the anode of the eighth diode, the second end of the fourth resistor, and the anode of the TVS tube are electrically connected to the ground terminal.

8. The control circuit according to claim 7, characterized in that: The voltage sampling circuit includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a voltage stabilizing diode, a ninth diode, a fifth capacitor, and an optical coupler; Among them, the anode of the voltage-stabilizing diode is electrically connected to the negative electrode of the power output end, and the cathode is electrically connected to the second end of the sixth resistor; the first end of the sixth resistor is electrically connected to the second end of the primary side of the optocoupler; the second end of the eighth resistor is electrically connected to the positive electrode of the power output end, and the second end is electrically connected to the cathode of the ninth diode; the anode of the ninth diode is electrically connected to the second end of the seventh resistor and the first end of the primary side of the optocoupler; the first end of the seventh resistor is electrically connected to the power supply end; the first end of the secondary side of the optocoupler is electrically connected to the main control circuit and the power supply end of the main control circuit; the second end of the secondary side of the optocoupler is electrically connected to the first end of the fifth capacitor, the first end of the fifth resistor, and the main control circuit; the second end of the fifth capacitor and the second end of the fifth resistor are electrically connected to the ground end.

9. A control device, characterized in that: The control device comprises a control circuit as described in any one of claims 1-8.

10. An electric welding machine, characterized in that: The electric welding machine comprises the control circuit as described in any one of claims 1 to 8 or the control device as described in claim 9.

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