Cutting machine output control circuit and cutting machine

Abstract

The present invention proposes a cutting machine output control circuit and a cutting machine, wherein a pulse signal is converted into a pulse width signal through a pulse width circuit and outputted to a main control circuit, and when the pulse width signal is greater than or equal to a preset voltage, the main control circuit outputs an arc pilot signal so that the arc pilot circuit outputs a constant current as the arc pilot current, thereby realizing identification that the main circuit is about to break the arc before the main circuit breaks the arc, thereby switching the constant current output by the output circuit from the main circuit to the arc pilot circuit before the main circuit breaks the arc, thereby avoiding the need to reopen the high-frequency circuit to start the arc again to establish the arc pilot current after the main circuit breaks the arc.

Description

Technical Field

[0001] The present application belongs to the field of plasma cutting technology, and in particular relates to a cutting control circuit and a cutting machine. Background Art

[0002] At present, traditional plasma cutting machines mainly establish pilot arcs after detecting the extinction of the main arc during grid cutting. There is a stage in which the arc disappears, and the entire current output is not a continuous process. It is difficult to cut metal with fine grid holes, and the establishment of the pilot arc requires high-frequency arc ignition. Frequent high-frequency arc ignition will cause damage to the equipment and harm to the human body.

[0003] Therefore, in the traditional technical solution, there is a problem of arc breaking during the process of switching from the main arc to the pilot arc. Summary of the invention

[0004] The purpose of the present application is to provide a cutting machine output control circuit, aiming to solve the problem of arc breaking in the process of switching from the main arc to the pilot arc in traditional cutting machines.

[0005] A first aspect of an embodiment of the present application provides a cutting machine output control circuit, comprising:

[0006] A pulse width circuit is configured to output a pulse signal according to the input first current analog quantity and the primary side detection current analog quantity, and convert the pulse signal into a pulse width signal;

[0007] an output circuit, connected to the pulse width circuit, configured to invert and output a first alternating current according to the pulse signal, convert the first alternating current into a second alternating current, and rectify the second alternating current to generate a constant current and output it to a main circuit or an arc-maintaining circuit;

[0008] an arc pilot circuit connected to the positive electrode of the output circuit and configured to output the constant current as an arc pilot current based on the arc pilot signal;

[0009] an AC current feedback circuit, connected to the output circuit and the pulse width circuit respectively, and configured to detect the current of the first AC power to generate the primary side detection current analog value; and

[0010] A main control circuit, connected to the pulse width circuit and the arc pilot circuit respectively, configured to output the arc pilot signal when the pulse width signal is greater than or equal to a preset voltage and output the first current analog value according to a first current setting value;

[0011] Wherein, the main circuit includes the output circuit, a gun head and a grounding clamp, the gun head is connected to the negative pole of the output circuit, the grounding clamp is connected to the positive pole of the output circuit, and the grounding clamp is configured to output the constant current as the main arc current; the arc pilot circuit includes the output circuit, the arc pilot circuit and the gun head, the gun head is respectively connected to the negative pole of the output circuit and the arc pilot circuit, and the positive pole of the output circuit is connected to the arc pilot circuit.

[0012] In one embodiment, the pulse width circuit includes:

[0013] a pulse width modulation circuit, connected to the main control circuit and the output circuit respectively, and configured to output the pulse signal according to the first current analog quantity and the primary side detection current analog quantity; and

[0014] The pulse width detection circuit is connected to the pulse width modulation circuit and the main control circuit, and is configured to convert the pulse signal into the pulse width signal.

[0015] In one embodiment, the output circuit includes:

[0016] an inverter component, connected to the pulse width circuit and configured to output a first alternating current according to the pulse signal;

[0017] a transformer component connected to the inverter component and configured to convert the first alternating current into the second alternating current; and

[0018] A rectifier component is connected to the transformer component and is configured to rectify the second AC voltage to generate the constant current.

[0019] In one embodiment, the cutting machine output control circuit further includes:

[0020] an output current feedback circuit, coupled to the main loop and connected to the main control circuit, configured to detect the constant current of the main loop when the main loop is turned on to generate a current sampling signal;

[0021] The main control circuit is further configured to stop outputting the arc pilot signal and output the first current analog value according to a second current setting value when the current sampling signal is greater than or equal to a first preset current.

[0022] In one embodiment, the arc pilot circuit comprises:

[0023] an arc pilot control circuit connected to the main control circuit and configured to output an arc pilot control signal according to the arc pilot signal;

[0024] A switch component; connected to the arc pilot control circuit and the output circuit, configured to output the constant current as the arc pilot current based on the arc pilot control signal.

[0025] In one embodiment, the arc pilot control circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a second capacitor, a third capacitor, a grounding capacitor, an optocoupler, a first diode, a second diode, a third diode, a light emitting diode, a first field effect transistor, a second field effect transistor, a third field effect transistor and a fourth field effect transistor;

[0026] The positive electrode of the optocoupler is connected to the first end of the second resistor, the negative electrode of the optocoupler is connected to the power ground, the emitter of the optocoupler, the first end of the seventh resistor, the first end of the eighth resistor and the first end of the fourth resistor are connected in common, the second end of the fourth resistor, the base of the first field effect transistor and the base of the second field effect transistor are connected in common, the second end of the eighth resistor is connected to the positive electrode of the light emitting diode, the emitter of the first field effect transistor, the emitter of the second field effect transistor, the positive electrode of the second diode, the negative electrode of the third diode, the first end of the ninth resistor, the first end of the fifth resistor and the first end of the first resistor are connected in common, the second end of the fifth resistor is connected to the gate of the third field effect transistor, the first end of the first resistor is connected to the gate of the fourth field effect transistor, the negative electrode of the first diode, the first end of the second capacitor, the first end of the third capacitor, the first end of the third resistor and the first end of the sixth resistor are connected in common, the collector of the optocoupler, the collector of the first field effect transistor and the collector of the first field effect transistor are connected in common. The cathode of the light-emitting diode and the cathode of the second diode are all connected to the internal power supply, the cathode of the light-emitting diode, the collector of the second field effect tube, the anode of the third diode, the second end of the ninth resistor, the source of the third field effect tube, the source of the fourth field effect tube, the first end of the first capacitor, the second end of the second capacitor, the second end of the third capacitor, the second end of the sixth resistor and the first end of the grounding capacitor are all connected to the power ground and are commonly connected to form the first output end of the arc pilot control signal of the arc pilot control circuit, the drain of the third field effect tube, the drain of the fourth field effect tube, the second end of the first capacitor, the anode of the first diode and the second end of the third resistor are commonly connected to form the second output end of the arc pilot control signal of the arc pilot control circuit, the first output end of the arc pilot control signal and the second output end of the arc pilot control signal constitute the output end of the arc pilot control signal of the arc pilot control circuit, the first end of the second resistor is the arc pilot signal input end of the arc pilot control circuit, and the second end of the grounding capacitor is connected to the protective ground wire.

[0027] In one embodiment, the pulse width detection circuit includes a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a first operational amplifier, a fourth capacitor, a fifth capacitor, a fourth diode and a fifth diode;

[0028] The first end of the tenth resistor, the first end of the eleventh resistor, the first end of the fifth capacitor and the non-inverting input end of the first operational amplifier are connected together, the inverting input end of the first operational amplifier, the output end of the first operational amplifier and the first end of the twelfth resistor are connected together, the second end of the twelfth resistor, the first end of the thirteenth resistor, the first end of the fourth capacitor, the cathode of the fourth diode and the anode of the fifth diode are connected together to form a pulse width signal output end of the pulse width detection circuit, the anode of the fourth diode, the thirteenth resistor, the second end of the fourth capacitor and the second end of the fifth capacitor are all connected to the power supply ground, the cathode of the fifth diode is connected to the first clamping voltage power supply, and the second end of the tenth resistor and the second end of the eleventh resistor form a pulse signal input end of the pulse width detection circuit.

[0029] In one embodiment, the pulse width modulation circuit includes a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a twenty-eighth resistor, a twenty-ninth resistor, a thirtieth resistor, a thirty-first resistor, a thirty-second resistor, a thirty-third resistor, a thirty-fourth resistor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a fourth operational amplifier, a fifth operational amplifier, a sixth operational amplifier, a seventh operational amplifier, a tenth diode, an eleventh diode, a twelfth diode, a thirteenth diode, a fourteenth diode, a fifteenth diode and a PWM modulation chip;

[0030] The first end of the twenty-first resistor, the first end of the twelfth capacitor and the first end of the twenty-second resistor are connected in common, the second end of the twenty-second resistor, the first end of the thirteenth capacitor and the non-inverting input end of the fourth operational amplifier are connected in common, the inverting input end of the fourth operational amplifier, the output end of the fourth operational amplifier and the first end of the twenty-third resistor are connected in common, the second end of the twenty-third resistor, the first end of the twenty-fourth resistor and the inverting input end of the fifth operational amplifier are connected in common, the non-inverting input end of the fifth operational amplifier is connected to the first end of the thirty-second resistor, the output end of the fifth operational amplifier, the second end of the twenty-fourth resistor and the first end of the twenty-fifth resistor are connected in common, The second end of the twenty-fifth resistor, the first end of the twenty-sixth resistor, the cathode of the tenth diode, the anode of the eleventh diode, the anode of the twelfth diode, the inverting input terminal of the sixth operational amplifier and the first end of the thirtieth resistor are connected in common, the second end of the twenty-sixth resistor is connected to the first end of the fourteenth capacitor, the cathode of the fifteenth diode, the second end of the fourteenth capacitor, the output terminal of the sixth operational amplifier and the first end of the twenty-seventh resistor are connected in common, the second end of the twenty-seventh resistor, the first end of the twenty-eighth resistor and the error amplifier in-phase input terminal of the PWM modulation chip are connected in common, the non-inverting input terminal of the sixth operational amplifier is connected to the first end of the twenty-ninth resistor The second end of the 30th resistor, the first end of the 31st resistor and the first end of the 15th capacitor are commonly connected, the second end of the 31st resistor is connected to the cathode of the 12th diode, the output end of the seventh operational amplifier, the inverting input end of the seventh operational amplifier and the anode of the 12th diode are commonly connected, the non-inverting input end of the seventh operational amplifier, the first end of the 33rd resistor and the first end of the 34th resistor are commonly connected, the second end of the 12th capacitor, the second end of the 13th capacitor, the second end of the 32nd resistor, the anode of the 10th diode, the cathode of the 11th diode, the second end of the 28th resistor, the second end of the 29th resistor, the first end of the 15th The second end of the capacitor, the second end of the thirty-third resistor, the first end of the sixteenth capacitor, the positive electrode of the thirteenth diode and the negative electrode of the fourteenth diode are all connected to the power ground, the negative electrode of the thirteenth diode is connected to the internal power supply, the second end of the twenty-first resistor is the first current analog input terminal of the pulse width modulation circuit, the positive electrode of the thirteenth diode, the negative electrode of the fourteenth diode, the second end of the sixteenth capacitor and the second end of the thirty-fourth resistor are connected together to form the primary detection current analog input terminal of the pulse width modulation circuit, and the first pulse output terminal of the PWM modulation chip and the second pulse output terminal of the PWM modulation chip constitute the pulse signal output terminal of the pulse width modulation circuit.

[0031] In one embodiment, the output current feedback circuit includes a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a sixth diode, a seventh diode, an eighth diode, a ninth diode, a second operational amplifier, a third operational amplifier and a current sensor;

[0032] The signal end of the current sensor, the anode of the sixth diode, the cathode of the seventh diode, the first end of the fourteenth resistor, the first end of the eighth capacitor and the non-inverting input end of the second operational amplifier are connected in common, the positive power supply end of the current sensor is connected in common with the first end of the sixth capacitor and is connected to the internal power supply, the negative power supply end of the current sensor is connected in common with the first end of the seventh capacitor and is connected to the internal negative power supply, the inverting input end of the second operational amplifier, the output end of the second operational amplifier, the first end of the fifteenth resistor are connected in common, the second end of the fifteenth resistor, the first end of the sixteenth resistor and the first end of the tenth capacitor are connected in common, the second end of the sixteenth resistor, the first end of the ninth capacitor and the non-inverting input end of the third operational amplifier are connected in common, the inverting input end of the third operational amplifier, the first end of the seventeenth resistor and the first end of the eighteenth resistor are connected in common, the second end of the eighteenth resistor, the The output end of the third operational amplifier, the first end of the nineteenth resistor and the second end of the tenth capacitor are connected in common, the second end of the nineteenth resistor, the anode of the eighth diode, the cathode of the ninth diode, the first end of the twentieth resistor and the first end of the eleventh capacitor are connected in common to form the current sampling signal output end of the output current feedback circuit, the ground end of the current sensor, the second end of the sixth capacitor, the second end of the seventh capacitor, the anode of the seventh diode, the second end of the eighth capacitor, the second end of the ninth capacitor, the second end of the seventeenth resistor, the anode of the ninth diode, the second end of the twentieth resistor and the second end of the eleventh capacitor are all grounded, the cathode of the sixth diode and the second end of the fourteenth resistor are both connected to the internal power supply, the cathode of the eighth diode is connected to the second clamping voltage power supply, and the coupling end of the current sensor is the constant current collection end of the output current feedback circuit.

[0033] A second aspect of the embodiments of the present application provides a cutting machine, comprising the gun head, the ground wire clamp for clamping the workpiece, and the cutting machine output control circuit as described in any of the above embodiments.

[0034] The beneficial effect of the embodiments of the present invention compared with the prior art is that the above-mentioned cutting machine output control circuit detects the pulse width signal of the pulse width circuit and identifies that the main circuit is about to break the arc before the main circuit breaks the arc, thereby switching the constant current output by the output circuit from the main circuit to the arc maintenance circuit before the main circuit breaks the arc, thereby avoiding the need to reopen the high-frequency circuit to start the arc again after the main circuit breaks the arc in order to establish the arc maintenance current. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a first exemplary structure of a cutting machine output control circuit provided in an embodiment of the present application;

[0036] Figure 2 A second exemplary structural diagram of a cutting machine output control circuit provided in an embodiment of the present application;

[0037] Figure 3 A third exemplary structural diagram of a cutting machine output control circuit provided in an embodiment of the present application;

[0038] Figure 4 An exemplary circuit schematic diagram of an arc pilot control circuit provided in an embodiment of the present application;

[0039] Figure 5 An exemplary circuit schematic diagram of a pulse width detection circuit provided in an embodiment of the present application;

[0040] Figure 6 An exemplary circuit schematic diagram of a pulse width modulation circuit provided in an embodiment of the present application;

[0041] Figure 7 An exemplary circuit schematic diagram of an output current feedback circuit provided in an embodiment of the present application;

[0042] Figure 8 An example circuit schematic diagram of a main control circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] Figure 1 The schematic diagram of the structure of the output control circuit of the cutting machine provided by the preferred embodiment of the present application is shown. For the convenience of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0045] A cutting machine output control circuit includes a pulse width circuit 110 , an output circuit 120 , an arc pilot circuit 130 , an AC current feedback circuit 140 and a main control circuit 150 .

[0046] The pulse width circuit 110 is configured to output a pulse signal according to the input first current analog quantity and the primary side detection current analog quantity, and to convert the pulse signal into a pulse width signal.

[0047] The output circuit 120 is connected to the pulse width circuit 110, and is configured to invert and output the first alternating current according to the pulse signal, convert the first alternating current into the second alternating current, and rectify the second alternating current to generate a constant current and output it to the main circuit or the arc-maintaining circuit.

[0048] The pilot circuit 130 is connected to the positive electrode of the output circuit 120 and is configured to output a constant current as a pilot current based on the pilot signal.

[0049] an AC current feedback circuit 140 , connected to the output circuit 120 and the pulse width circuit 110 , respectively, and configured to detect the current of the first AC power to generate a primary side detection current analog value; and

[0050] The main control circuit 150 is connected to the pulse width circuit 110 and the arc pilot circuit 130 respectively, and is configured to output an arc pilot signal when the pulse width signal is greater than or equal to a preset voltage and output a first current analog value according to a first current setting value.

[0051] Among them, the main circuit includes an output circuit 120, a gun head 200 and a grounding clamp 300, the positive pole of the output circuit 120 is connected to the grounding clamp 300, the negative pole of the output circuit 120 is connected to the gun head 200, and the grounding clamp 300 is configured to output a constant current as the main arc current; the arc pilot circuit includes an output circuit 120, an arc pilot circuit 130 and a gun head 200, the positive pole of the output circuit 120 is connected to the arc pilot circuit 130, the arc pilot circuit 130 is connected to the gun head 200, and the gun head 200 is also connected to the negative pole of the output circuit 120.

[0052] In this embodiment, when the cutting machine is about to cut to the blank space, the distance between the gun head 200 and the grounding clamp 300 (or the workpiece connected to the grounding clamp 300, for the convenience of description, the two will be collectively referred to as the grounding clamp 300 below) gradually increases, and the resistance value between the gun head 200 and the grounding clamp 300 gradually increases, so that the voltage value of the first alternating current output by the output circuit 120 gradually increases, and then the primary detection current analog value of the first alternating current gradually increases, and then the pulse width signal of the pulse signal output by the pulse width circuit 110 gradually increases. When the pulse width signal is greater than or equal to the preset voltage, the main control circuit 150 outputs an arc pilot signal to the arc pilot circuit 130 to And according to the preset first current setting value (arc-maintaining current setting value), the first current analog quantity is outputted, and the output circuit 120 outputs a corresponding pulse signal according to the first current analog quantity and the primary side detection current analog quantity to control the output circuit 120 to output a constant current for arc maintenance. The arc maintenance circuit 130 is turned on when the arc maintenance signal is input and outputs the constant current as the arc maintenance current to the arc maintenance circuit, so that the output of the constant current is switched from the main circuit to the arc maintenance circuit. After the arc maintenance circuit is turned on, there will be a period of time when the main circuit is in a conducting state without arc breaking. At this time, there is a small part of the constant current in the main circuit. As the distance between the gun head 200 and the grounding clamp 300 increases, the main circuit will break the arc. Among them, when the cutting machine output control circuit of this embodiment cuts a grid-shaped workpiece, it can transfer the constant current from the main circuit to the arc pilot circuit before the main circuit is disconnected, thereby avoiding the interruption of the constant current. Therefore, when cutting a workpiece with a smaller grid, the cutting can be continued, and when the arc pilot circuit is turned on, the output arc pilot current is controlled by a preset arc pilot current setting value, which can reduce the consumption of wearing parts. In addition, the cutting machine output control circuit of this embodiment can identify that the main circuit is about to be disconnected before the main circuit is disconnected by detecting the pulse width signal of the pulse width circuit 110, so that Before the main circuit breaks the arc, the constant current output by the output circuit 120 is switched from the main circuit to the arc pilot circuit, thereby avoiding the need to re-strike the arc pilot circuit with high frequency after the main circuit breaks the arc. In addition, because the constant current of the main circuit is generated by pulse signal modulation, the trend of the constant current of the main circuit to change can be captured by detecting the pulse width signal before the constant current of the main circuit actually changes. Therefore, it will be faster to judge the timeliness of the main circuit being disconnected, thereby better avoiding the arc breaking in the main circuit before the arc pilot circuit is turned on, and the constant current can be accurately switched to the arc pilot circuit before the main circuit is disconnected.

[0053] The gun head 200 includes an electrode and a nozzle, the nozzle is connected to the negative electrode of the output circuit 120, and the electrode is connected to the positive electrode of the output circuit 120. The main circuit includes the output circuit 120, the nozzle and the ground clamp 300, and the arc pilot circuit includes the output circuit 120, the arc pilot circuit 130, the electrode and the nozzle. The nozzle and the electrode can be directly connected, or the nozzle and the electrode can be connected when the arc pilot current breaks through the medium. Figure 2 In one embodiment, the pulse width circuit 110 includes a pulse width modulation circuit 111 and a pulse width detection circuit 112 .

[0054] The pulse width modulation circuit 111 is connected to the main control circuit 150 and the output circuit 120 respectively, and is configured to output a pulse signal according to the first current analog quantity and the primary side detection current analog quantity.

[0055] The pulse width detection circuit 112 is connected to the pulse width modulation circuit 111 and the main control circuit 150 , and is configured to convert the pulse signal into a pulse width signal.

[0056] In this embodiment, the pulse width modulation circuit 111 outputs a pulse signal to control the output circuit 120 based on the first current analog quantity output from the main control circuit 150 and the primary side detection current analog quantity output from the output circuit 120, forming a negative feedback regulation, which can make the constant current output by the output circuit 120 equal to a preset value. The pulse width detection circuit 112 converts the pulse signal output by the pulse width modulation circuit 111 into a pulse width signal for monitoring the constant current output by the output circuit 120.

[0057] See also Figure 2 In one embodiment, the output circuit 120 includes an inverter component 121 , a transformer component 122 and a rectifier component 123 .

[0058] The inverter component 121 is connected to the pulse width circuit 110 and is configured to output a first alternating current according to the pulse signal.

[0059] The transformer component 122 is connected to the inverter component 121 and is configured to transform the first alternating current into the second alternating current.

[0060] The rectifying component 123 is connected to the transformer component 122 and is configured to rectify the second AC voltage to generate a constant current.

[0061] In this embodiment, the inverter component 121 inverts the DC power supply into a first alternating current according to a pulse signal, and then boosts the first alternating current into a second alternating current through the transformer component 122. The rectifier component 123 rectifies the second alternating current to generate a constant current output to the main circuit or the arc-maintaining circuit, which can improve the stability of the output constant current. The AC current feedback circuit 140 is coupled to the primary coil of the transformer component 122. Therefore, the AC current feedback circuit 140 can use a current transformer to collect the current of the first alternating current to generate a primary detection current analog quantity, which can reduce the device cost compared to using a current sensor.

[0062] Among them, the inverter component 121 can be an IGBT (Insulated Gate Bipolar Transistor) inverter component 121, the transformer component 122 can be a transformer, and the rectifier component 123 can be a half-wave rectifier, a full-wave rectifier, a full-bridge rectifier, etc. The specific structures of the inverter component 121, the transformer component 122 and the rectifier component 123 are not limited here.

[0063] See also Figure 3 In one embodiment, the cutting machine output control circuit further includes:

[0064] The output current feedback circuit 160 is coupled to the main circuit and connected to the main control circuit 150, and is configured to detect the constant current of the main circuit when the main circuit is turned on to generate a current sampling signal;

[0065] The main control circuit 150 is further configured to stop outputting the arc pilot signal and output the first current analog value according to the second current setting value when the current sampling signal is greater than or equal to the first preset current.

[0066] In this embodiment, the output current feedback circuit 160 is coupled to the main circuit, and when the main circuit is turned on, the current sampling signal of the constant current circuit flowing through the main circuit is output to the main control circuit 150. When the current sampling signal is greater than or equal to the first preset current, the main control circuit 150 outputs the first current analog quantity to control the pulse width circuit 110 according to the second current preset value (main arc current setting value). When the arc pilot circuit is turned on, when the distance between the gun head 200 and the ground wire clamp 300 is less than a certain value (the value depends on the voltage difference and resistance between the gun head 200 and the ground wire clamp 300), the gun head 200 and the ground wire clamp 300 are turned on, so that the constant current of the main circuit increases. When the output current feedback circuit 160 collects that the current sampling signal of the main circuit is greater than or equal to the first preset current, the main control circuit 150 stops outputting the arc pilot signal and outputs the first current analog quantity to control the output circuit 120 according to the second current setting value, so that the constant current is converted from being output to the arc pilot circuit to being output to the main circuit, thereby ensuring that the main circuit can be supplied with constant current in time when cutting the workpiece.

[0067] See also Figure 2 In one embodiment, the arc pilot circuit 130 includes:

[0068] The arc pilot control circuit 131 is connected to the main control circuit 150 and is configured to output an arc pilot control signal according to the arc pilot signal.

[0069] The switch component 132 is connected to the arc pilot control circuit 131 and the output circuit 120, and is configured to output a constant current as an arc pilot current based on the arc pilot control signal.

[0070] In this embodiment, the arc pilot control circuit 131 converts the arc pilot signal input from the main control circuit 150 into an arc pilot control signal to control the switch component 132 to turn on, so that the output circuit 120 outputs the constant current as the arc pilot current through the switch component 132.

[0071] See also Figure 4 In one embodiment, the arc pilot control circuit 131 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a first capacitor C1, a second capacitor C2, a third capacitor C3, a grounding capacitor CC, an optocoupler OU1, a first diode D1, a second diode D2, a third diode D3, a light emitting diode LED1, a first field effect transistor Q1, a second field effect transistor Q2, a third field effect transistor Q3 and a fourth field effect transistor Q4;

[0072] The positive electrode of the optocoupler OU1 is connected to the first end of the second resistor R2, the negative electrode of the optocoupler OU1 is connected to the power ground, the emitter of the optocoupler OU1, the first end of the seventh resistor R7, the first end of the eighth resistor R8 and the first end of the fourth resistor R4 are connected together, the second end of the fourth resistor R4, the base of the first field effect transistor Q1 and the base of the second field effect transistor Q2 are connected together, the second end of the eighth resistor R8 is connected to the positive electrode of the light emitting diode LED1, the emitter of the first field effect transistor Q1, the emitter of the second field effect transistor Q2, the second diode D The positive electrode of the first diode D1, the first end of the second capacitor C2, the first end of the third capacitor C3, the first end of the third resistor R3 and the first end of the sixth resistor R6 are connected together, the collector of the optical coupler OU1, the collector of the first field effect transistor Q1 and the collector of the optical coupler OU2 are connected together, and the positive electrode of the first diode D2, the negative electrode of the third diode D3, the first end of the ninth resistor R9, the first end of the fifth resistor R5 and the first end of the first resistor R1 are connected together, the second end of the fifth resistor R5 is connected to the gate of the third field effect transistor Q3, the first end of the first resistor R1 is connected to the gate of the fourth field effect transistor Q4, the negative electrode of the first diode D1, the first end of the second capacitor C2, the first end of the third capacitor C3, the first end of the third resistor R3 and the first end of the sixth resistor R6 are connected together, the collector of the optical coupler OU1, the collector of the first field effect transistor Q1 and the collector of the optical coupler OU2 are connected together, and the collector of the optical coupler OU2 is connected to the collector of the first field effect transistor Q1. The cathode of the light emitting diode LED1, the collector of the second field effect transistor Q2, the anode of the third diode D3, the second end of the ninth resistor R9, the source of the third field effect transistor Q3, the source of the fourth field effect transistor Q4, the first end of the first capacitor C1, the second end of the second capacitor C2, the second end of the third capacitor C3, the second end of the sixth resistor R6 and the first end of the grounding capacitor CC are all connected to the power ground and are connected together to form the arc pilot control signal of the arc pilot control circuit 131. An output end, the drain of the third field effect transistor Q3, the drain of the fourth field effect transistor Q4, the second end of the first capacitor C1, the anode of the first diode D1 and the second end of the third resistor R3 are connected together to form the second output end of the arc pilot control signal of the arc pilot control circuit 131. The first output end of the arc pilot control signal and the second output end of the arc pilot control signal form the output end of the arc pilot control signal of the arc pilot control circuit 131. The first end of the second resistor R2 is the input end of the arc pilot signal of the arc pilot control circuit 131. The second end of the grounding capacitor CC is connected to the protective ground wire.

[0073] See also Figure 5 , the pulse width detection circuit 112 includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a first operational amplifier U1A, a fourth capacitor C4, a fifth capacitor C5, a fourth diode D4 and a fifth diode D5;

[0074] The first end of the tenth resistor R10, the first end of the eleventh resistor R11, the first end of the fifth capacitor C5 and the non-inverting input end of the first operational amplifier U1A are connected together, the inverting input end of the first operational amplifier U1A, the output end of the first operational amplifier U1A and the first end of the twelfth resistor R12 are connected together, the second end of the twelfth resistor R12, the first end of the thirteenth resistor R13, the first end of the fourth capacitor C4, the cathode of the fourth diode D4 and the anode of the fifth diode D5 are connected together to form a pulse width signal output end of the pulse width detection circuit 112, the anode of the fourth diode D4, the thirteenth resistor R13, the second end of the fourth capacitor C4 and the second end of the fifth capacitor C5 are all connected to the power supply ground, the cathode of the fifth diode D5 is connected to the first clamping voltage power supply, and the second end of the tenth resistor R10 and the second end of the eleventh resistor R11 form a pulse signal input end of the pulse width detection circuit 112.

[0075] See also Figure 6 In one embodiment, the pulse width modulation circuit 111 includes a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a twenty-eighth resistor R28, a twenty-ninth resistor R29, a thirtieth resistor R30, a thirty-first resistor R31, a thirty-second resistor R32, a thirty-third resistor R33, a thirty-fourth resistor R34, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, a fifteenth capacitor C15, a sixteenth capacitor C16, a fourth operational amplifier U1D, a fifth operational amplifier U1E, a sixth operational amplifier U1F, a seventh operational amplifier U1G, a tenth diode D10, an eleventh diode D11, a twelfth diode D12, a thirteenth diode D13, a fourteenth diode D14, a fifteenth diode D15 and a PWM modulation chip U2;

[0076] The first end of the twenty-first resistor R21, the first end of the twelfth capacitor C12 and the first end of the twenty-second resistor R22 are connected in common, the second end of the twenty-second resistor R22, the first end of the thirteenth capacitor C13 and the non-inverting input terminal of the fourth operational amplifier U1D are connected in common, the inverting input terminal of the fourth operational amplifier U1D, the output terminal of the fourth operational amplifier U1D and the first end of the twenty-third resistor R23 are connected in common, the second end of the twenty-third resistor R23, the first end of the twenty-fourth resistor R24 ​​and the inverting input terminal of the fifth operational amplifier U1E are connected in common, the non-inverting input terminal of the fifth operational amplifier U1E is connected to the first end of the thirty-second resistor R32, and the output terminal of the fifth operational amplifier U1E is connected in common. The output end, the second end of the twenty-fourth resistor R24 ​​and the first end of the twenty-fifth resistor R25 are connected in common, the second end of the twenty-fifth resistor R25, the first end of the twenty-sixth resistor R26, the cathode of the tenth diode D10, the anode of the eleventh diode D11, the anode of the twelfth diode D12, the inverting input end of the sixth operational amplifier U1F and the first end of the thirtieth resistor R30 are connected in common, the second end of the twenty-sixth resistor R26 is connected to the first end of the fourteenth capacitor C14, the cathode of the fifteenth diode D15, the second end of the fourteenth capacitor C14, the output end of the sixth operational amplifier U1F and the first end of the twenty-seventh resistor R27 are connected in common, and the twenty-seventh resistor R27 The second end of the twenty-eighth resistor R28, the first end of the twenty-eighth resistor R28 and the error amplifier in-phase input terminal EA of the PWM modulation chip U2 are connected together, the non-inverting input terminal of the sixth operational amplifier is connected to the first end of the twenty-ninth resistor R29, the second end of the thirtieth resistor R30, the first end of the thirty-first resistor R31 and the first end of the fifteenth capacitor C15 are connected together, the second end of the thirty-first resistor R31 is connected to the cathode of the twelfth diode D12, the output end of the seventh operational amplifier U1G, the inverting input end of the seventh operational amplifier U1G and the anode of the twelfth diode D12 are connected together, the non-inverting input end of the seventh operational amplifier U1G, the first end of the thirty-third resistor R33 and the first end of the thirty-fourth resistor R The first end of the twelfth capacitor C12, the second end of the thirteenth capacitor C13, the second end of the thirty-second resistor R32, the anode of the tenth diode D10, the cathode of the eleventh diode D11, the second end of the twenty-eighth resistor R28, the second end of the twenty-ninth resistor R29, the second end of the fifteenth capacitor C15, the second end of the thirty-third resistor R33, the first end of the sixteenth capacitor C16, the anode of the thirteenth diode D13 and the cathode of the fourteenth diode D14 are all connected to the power ground, the cathode of the thirteenth diode D13 is connected to the internal power supply, the second end of the twenty-first resistor R21 is the first current analog input terminal of the pulse width modulation circuit 111,The anode of the thirteenth diode D13, the cathode of the fourteenth diode D14, the second end of the sixteenth capacitor C16 and the second end of the thirty-fourth resistor R34 are connected together to form the primary detection current analog input end of the pulse width modulation circuit 111, and the first pulse output end OUT1 of the PWM modulation chip U2 and the second pulse output end OUT2 of the PWM modulation chip U2 form the pulse signal output end of the pulse width modulation circuit 111.

[0077] See also Figure 7 In one embodiment, the output current feedback circuit 160 includes a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a sixth diode D6, a seventh diode D7, an eighth diode D8, a ninth diode D9, a second operational amplifier U1B, a third operational amplifier U1C and a current sensor XH1;

[0078] The signal end of the current sensor XH1, the anode of the sixth diode D6, the cathode of the seventh diode D7, the first end of the fourteenth resistor R14, the first end of the eighth capacitor C8 and the non-inverting input end of the second operational amplifier U1B are connected together, the positive power supply end of the current sensor XH1 is connected together with the first end of the sixth capacitor C6 and is connected to the internal power supply, the negative power supply end of the current sensor XH1 is connected together with the first end of the seventh capacitor C7 and is connected to the internal negative power supply, the inverting input end of the second operational amplifier U1B, the output end of the second operational amplifier U1B, the first end of the fifteenth resistor R15 are connected together, the second end of the fifteenth resistor R15, the first end of the sixteenth resistor R16 and the first end of the tenth capacitor C10 are connected together, the second end of the sixteenth resistor R16, the first end of the ninth capacitor C9 and the non-inverting input end of the third operational amplifier U1C are connected together, the inverting input end of the third operational amplifier U1C, the first end of the seventeenth resistor R17 and the first end of the eighteenth resistor R18 are connected together, and the second end of the eighteenth resistor R18 , the output end of the third operational amplifier U1C, the first end of the nineteenth resistor R19 and the second end of the tenth capacitor C10 are connected together, the second end of the nineteenth resistor R19, the anode of the eighth diode D8, the cathode of the ninth diode D9, the first end of the twentieth resistor R20 and the first end of the eleventh capacitor C11 are connected together to form the current sampling signal output end of the output current feedback circuit 160, the ground end of the current sensor XH1, the second end of the sixth capacitor C6, the second end of the seventh capacitor C7, the anode of the seventh diode D7, the second end of the eighth capacitor C8, the second end of the ninth capacitor C9, the second end of the seventeenth resistor R17, the anode of the ninth diode D9, the second end of the twentieth resistor R20 and the second end of the eleventh capacitor C11 are all grounded, the cathode of the sixth diode D6 and the second end of the fourteenth resistor R14 are both connected to the internal power supply, the cathode of the eighth diode D8 is connected to the second clamping voltage power supply, and the coupling end of the current sensor XH1 is the constant current collection end of the output current feedback circuit 160.

[0079] See also Figure 8 The main control circuit 150 includes a current control chip U3, a first analog-to-digital conversion input terminal PA1 of the current control chip U3 is a pulse width signal input terminal of the main control circuit 150, a second analog-to-digital conversion input terminal PA2 of the current control chip U3 is a current sampling signal input terminal of the main control circuit 150, a universal input and output terminal I / O of the current control chip U3 is an arc maintenance signal output terminal of the main control circuit 150, and an analog output terminal OUT of the current control chip U3 is a first current analog output terminal of the main control circuit 150.

[0080] The following is combined with the working principle Figures 4 to 8The exemplary circuit schematic diagram shown is used for explanation. The analog output terminal OUT of the current control chip U3 outputs the first current analog quantity according to the second current preset value. The first current analog quantity is sequentially input to the reverse input terminal of the sixth operational amplifier U1F through the twenty-first resistor R21, the twenty-second resistor R22, the fourth operational amplifier U1D, the twenty-third resistor R23, the fifth operational amplifier U1E and the twenty-fifth resistor R25. The primary side detection current analog quantity is sequentially input to the reverse input terminal of the sixth operational amplifier U1F through the thirty-fourth resistor R34, the seventh operational amplifier U1G, the twelfth diode D12, the thirty-first resistor R31 and the thirtieth resistor R30. The sixth operational amplifier U1F converts the first current analog quantity and the primary side detection current analog quantity into a reverse input terminal. The error of the current analog quantity is amplified and then input to the error amplification same-direction input terminal EA of the PWM modulation chip U2 through the twenty-seventh resistor R27, and then the first pulse output terminal OUT1 of the PWM modulation chip U2 and the second pulse output terminal OUT2 of the PWM modulation chip U2 both output pulse signals, and the pulse signal output by the first pulse output terminal OUT1 is input to the positive phase input terminal of the first operational amplifier U1A through the tenth resistor R10, and the pulse signal output by the second pulse output terminal OUT2 is input to the positive phase input terminal of the first operational amplifier U1A through the eleventh resistor R11, and the first operational amplifier U1A amplifies the pulse signal, and then at the twelfth resistor R12 and the thirteenth resistor R1 3 and the fourth capacitor C4 are filtered to form a pulse width signal, the pulse width signal is input to the current control chip U3 through the first analog-to-digital conversion input terminal PA1 of the current control chip U3, the current control chip U3 compares the pulse width signal with the preset voltage, when the pulse width signal is greater than or equal to the preset voltage, the universal input and output terminal I / O of the current control chip U3 outputs an arc-maintaining signal and the analog output terminal OUT outputs a first current analog quantity according to the first current setting value, the arc-maintaining signal is input to the positive electrode of the optical coupler OU1 through the second resistor R2, the optical coupler OU1 is turned on, and the emitter of the optical coupler OU1 outputs a high level, the high level turns on the first field effect transistor Q1 and the second field effect transistor Q2, thereby turning on the third field effect transistor Q3 and the fourth field effect transistor Q4. The field effect transistor Q4 is turned on, so that the arc pilot control circuit 131 outputs a high level control switch component 132 to turn on so that the arc pilot loop is turned on. Then, the constant current of the main loop collected by the current sensor XH1 is output through the signal end of the current sensor XH1. The constant current is converted into a current sampling signal through the second operational amplifier U1B, the fifteenth resistor R15, the sixteenth resistor R16, the third operational amplifier U1C and the nineteenth resistor R19 in sequence and output to the second analog-to-digital conversion input terminal PA2 of the current control chip U3. When the current sampling signal is greater than or equal to the first preset current, the current control chip U3 stops outputting the arc pilot signal and outputs the first current analog value according to the second current setting value.

[0081] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A cutting machine output control circuit, characterized in that: include: A pulse width circuit is configured to output a pulse signal according to the input first current analog quantity and the primary side detection current analog quantity, and convert the pulse signal into a pulse width signal; an output circuit, connected to the pulse width circuit, configured to invert and output a first alternating current according to the pulse signal, convert the first alternating current into a second alternating current, and rectify the second alternating current to generate a constant current and output it to a main circuit or an arc-maintaining circuit; an arc pilot circuit connected to the output circuit and configured to output the constant current as an arc pilot current based on an arc pilot signal; an AC current feedback circuit, connected to the output circuit and the pulse width circuit respectively, and configured to detect the current of the first AC power to generate the primary side detection current analog value; as well as A main control circuit, connected to the pulse width circuit and the arc pilot circuit respectively, configured to output the arc pilot signal when the pulse width signal is greater than or equal to a preset voltage and output the first current analog value according to a first current setting value; Wherein, the main circuit includes the output circuit, a gun head and a grounding clamp, the gun head is connected to the negative pole of the output circuit, the grounding clamp is connected to the positive pole of the output circuit, and the grounding clamp is configured to output the constant current as the main arc current; the arc pilot circuit includes the output circuit, the arc pilot circuit and the gun head, the gun head is respectively connected to the negative pole of the output circuit and the arc pilot circuit, and the positive pole of the output circuit is connected to the arc pilot circuit; The pulse width circuit comprises: a pulse width modulation circuit, connected to the main control circuit and the output circuit respectively, and configured to output the pulse signal according to the first current analog quantity and the primary side detection current analog quantity; and a pulse width detection circuit, connected to the pulse width modulation circuit and the main control circuit, and configured to convert the pulse signal into the pulse width signal; The pulse width modulation circuit includes a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a twenty-eighth resistor, a twenty-ninth resistor, a thirtieth resistor, a thirty-first resistor, a thirty-second resistor, a thirty-third resistor, a thirty-fourth resistor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a fourth operational amplifier, a fifth operational amplifier, a sixth operational amplifier, a seventh operational amplifier, a tenth diode, an eleventh diode, a twelfth diode, a thirteenth diode, a fourteenth diode, a fifteenth diode and a PWM modulation chip; The first end of the twenty-first resistor, the first end of the twelfth capacitor and the first end of the twenty-second resistor are connected in common, the second end of the twenty-second resistor, the first end of the thirteenth capacitor and the non-inverting input end of the fourth operational amplifier are connected in common, the inverting input end of the fourth operational amplifier, the output end of the fourth operational amplifier and the first end of the twenty-third resistor are connected in common, the second end of the twenty-third resistor, the first end of the twenty-fourth resistor and the inverting input end of the fifth operational amplifier are connected in common, the non-inverting input end of the fifth operational amplifier is connected to the first end of the thirty-second resistor, the output end of the fifth operational amplifier, the second end of the twenty-fourth resistor and the first end of the twenty-fifth resistor are connected in common, The second end of the twenty-fifth resistor, the first end of the twenty-sixth resistor, the cathode of the tenth diode, the anode of the eleventh diode, the anode of the twelfth diode, the inverting input terminal of the sixth operational amplifier and the first end of the thirtieth resistor are connected in common, the second end of the twenty-sixth resistor is connected to the first end of the fourteenth capacitor, the cathode of the fifteenth diode, the second end of the fourteenth capacitor, the output terminal of the sixth operational amplifier and the first end of the twenty-seventh resistor are connected in common, the second end of the twenty-seventh resistor, the first end of the twenty-eighth resistor and the error amplifier in-phase input terminal of the PWM modulation chip are connected in common, the non-inverting input terminal of the sixth operational amplifier is connected to the first end of the twenty-ninth resistor The second end of the 30th resistor, the first end of the 31st resistor and the first end of the 15th capacitor are commonly connected, the second end of the 31st resistor is connected to the cathode of the 12th diode, the output end of the seventh operational amplifier, the inverting input end of the seventh operational amplifier and the anode of the 12th diode are commonly connected, the non-inverting input end of the seventh operational amplifier, the first end of the 33rd resistor and the first end of the 34th resistor are commonly connected, the second end of the 12th capacitor, the second end of the 13th capacitor, the second end of the 32nd resistor, the anode of the 10th diode, the cathode of the 11th diode, the second end of the 28th resistor, the second end of the 29th resistor, the first end of the 15th The second end of the capacitor, the second end of the thirty-third resistor, the first end of the sixteenth capacitor, the positive electrode of the thirteenth diode and the negative electrode of the fourteenth diode are all connected to the power ground, the negative electrode of the thirteenth diode is connected to the internal power supply, the second end of the twenty-first resistor is the first current analog input terminal of the pulse width modulation circuit, the positive electrode of the thirteenth diode, the negative electrode of the fourteenth diode, the second end of the sixteenth capacitor and the second end of the thirty-fourth resistor are connected together to form the primary detection current analog input terminal of the pulse width modulation circuit, and the first pulse output terminal of the PWM modulation chip and the second pulse output terminal of the PWM modulation chip constitute the pulse signal output terminal of the pulse width modulation circuit.

2. The cutting machine output control circuit according to claim 1, characterized in that: The output circuit comprises: an inverter component, connected to the pulse width circuit and configured to output a first alternating current according to the pulse signal; a transformer component, connected to the inverter component, and configured to convert the first alternating current into the second alternating current; and A rectifier component is connected to the transformer component and is configured to rectify the second AC voltage to generate the constant current.

3. The cutting machine output control circuit according to claim 1, characterized in that: The cutting machine output control circuit also includes: an output current feedback circuit, coupled to the main loop and connected to the main control circuit, configured to detect the constant current of the main loop when the main loop is turned on to generate a current sampling signal; The main control circuit is further configured to stop outputting the arc pilot signal and output the first current analog value according to a second current setting value when the current sampling signal is greater than or equal to a first preset current.

4. The cutting machine output control circuit according to claim 1, characterized in that: The arc pilot circuit comprises: an arc pilot control circuit connected to the main control circuit and configured to output an arc pilot control signal according to the arc pilot signal; A switch component; connected to the arc pilot control circuit and the output circuit, configured to output the constant current as the arc pilot current based on the arc pilot control signal.

5. The cutting machine output control circuit according to claim 4, characterized in that: The arc pilot control circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a second capacitor, a third capacitor, a grounding capacitor, an optocoupler, a first diode, a second diode, a third diode, a light emitting diode, a first field effect transistor, a second field effect transistor, a third field effect transistor and a fourth field effect transistor; The positive electrode of the optocoupler is connected to the first end of the second resistor, the negative electrode of the optocoupler is connected to the power ground, the emitter of the optocoupler, the first end of the seventh resistor, the first end of the eighth resistor and the first end of the fourth resistor are connected in common, the second end of the fourth resistor, the base of the first field effect transistor and the base of the second field effect transistor are connected in common, the second end of the eighth resistor is connected to the positive electrode of the light emitting diode, the emitter of the first field effect transistor, the emitter of the second field effect transistor, the positive electrode of the second diode, the negative electrode of the third diode, the first end of the ninth resistor, the first end of the fifth resistor and the first end of the first resistor are connected in common, the second end of the fifth resistor is connected to the gate of the third field effect transistor, the first end of the first resistor is connected to the gate of the fourth field effect transistor, the negative electrode of the first diode, the first end of the second capacitor, the first end of the third capacitor, the first end of the third resistor and the first end of the sixth resistor are connected in common, the collector of the optocoupler, the collector of the first field effect transistor and the collector of the first field effect transistor are connected in common. The cathode of the light-emitting diode and the cathode of the second diode are all connected to the internal power supply, the cathode of the light-emitting diode, the collector of the second field effect tube, the anode of the third diode, the second end of the ninth resistor, the source of the third field effect tube, the source of the fourth field effect tube, the first end of the first capacitor, the second end of the second capacitor, the second end of the third capacitor, the second end of the sixth resistor and the first end of the grounding capacitor are all connected to the power ground and are commonly connected to form the first output end of the arc pilot control signal of the arc pilot control circuit, the drain of the third field effect tube, the drain of the fourth field effect tube, the second end of the first capacitor, the anode of the first diode and the second end of the third resistor are commonly connected to form the second output end of the arc pilot control signal of the arc pilot control circuit, the first output end of the arc pilot control signal and the second output end of the arc pilot control signal constitute the output end of the arc pilot control signal of the arc pilot control circuit, the first end of the second resistor is the arc pilot signal input end of the arc pilot control circuit, and the second end of the grounding capacitor is connected to the protective ground wire.

6. The cutting machine output control circuit according to claim 1, characterized in that: The pulse width detection circuit includes a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a first operational amplifier, a fourth capacitor, a fifth capacitor, a fourth diode and a fifth diode; The first end of the tenth resistor, the first end of the eleventh resistor, the first end of the fifth capacitor and the non-inverting input end of the first operational amplifier are connected together, the inverting input end of the first operational amplifier, the output end of the first operational amplifier and the first end of the twelfth resistor are connected together, the second end of the twelfth resistor, the first end of the thirteenth resistor, the first end of the fourth capacitor, the cathode of the fourth diode and the anode of the fifth diode are connected together to form a pulse width signal output end of the pulse width detection circuit, the anode of the fourth diode, the thirteenth resistor, the second end of the fourth capacitor and the second end of the fifth capacitor are all connected to the power supply ground, the cathode of the fifth diode is connected to the first clamping voltage power supply, and the second end of the tenth resistor and the second end of the eleventh resistor form a pulse signal input end of the pulse width detection circuit.

7. The cutting machine output control circuit according to claim 3, characterized in that: The output current feedback circuit includes a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a sixth diode, a seventh diode, an eighth diode, a ninth diode, a second operational amplifier, a third operational amplifier and a current sensor; The signal end of the current sensor, the anode of the sixth diode, the cathode of the seventh diode, the first end of the fourteenth resistor, the first end of the eighth capacitor and the non-inverting input end of the second operational amplifier are connected in common, the positive power supply end of the current sensor is connected in common with the first end of the sixth capacitor and is connected to the internal power supply, the negative power supply end of the current sensor is connected in common with the first end of the seventh capacitor and is connected to the internal negative power supply, the inverting input end of the second operational amplifier, the output end of the second operational amplifier, the first end of the fifteenth resistor are connected in common, the second end of the fifteenth resistor, the first end of the sixteenth resistor and the first end of the tenth capacitor are connected in common, the second end of the sixteenth resistor, the first end of the ninth capacitor and the non-inverting input end of the third operational amplifier are connected in common, the inverting input end of the third operational amplifier, the first end of the seventeenth resistor and the first end of the eighteenth resistor are connected in common, the second end of the eighteenth resistor, the The output end of the third operational amplifier, the first end of the nineteenth resistor and the second end of the tenth capacitor are connected in common, the second end of the nineteenth resistor, the anode of the eighth diode, the cathode of the ninth diode, the first end of the twentieth resistor and the first end of the eleventh capacitor are connected in common to form the current sampling signal output end of the output current feedback circuit, the ground end of the current sensor, the second end of the sixth capacitor, the second end of the seventh capacitor, the anode of the seventh diode, the second end of the eighth capacitor, the second end of the ninth capacitor, the second end of the seventeenth resistor, the anode of the ninth diode, the second end of the twentieth resistor and the second end of the eleventh capacitor are all grounded, the cathode of the sixth diode and the second end of the fourteenth resistor are both connected to the internal power supply, the cathode of the eighth diode is connected to the second clamping voltage power supply, and the coupling end of the current sensor is the constant current collection end of the output current feedback circuit.

8. A cutting machine, characterized in that: It comprises the gun head, the grounding clamp for clamping the workpiece and the cutting machine output control circuit as described in any one of claims 1 to 7.

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