CN111958094A

CN111958094A - Cutting machine output control circuit and cutting machine

Info

Publication number: CN111958094A
Application number: CN202010824261.0A
Authority: CN
Inventors: 肖文成; 陆代亮
Original assignee: Shenzhen Jasic Technology Co ltd
Current assignee: Shenzhen Jasic Technology Co ltd
Priority date: 2020-08-17
Filing date: 2020-08-17
Publication date: 2020-11-20

Abstract

The invention provides 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 is output to a main control circuit, the main control circuit outputs a pilot arc signal when the pulse width signal is larger than or equal to a preset voltage, so that a pilot arc circuit outputs a constant current as a pilot arc current, and the purpose that the main circuit is about to break an arc is realized before the main circuit breaks the arc is realized, so that the constant current output by an output circuit is switched from the main circuit to the pilot arc circuit before the main circuit breaks the arc, and the problem that the high-frequency circuit needs to be opened again for arc striking again for establishing the pilot arc current after the main circuit breaks the arc is avoided.

Description

Cutting machine output control circuit and cutting machine

Technical Field

The application belongs to the technical field of plasma cutting, especially relates to a cutting control circuit and cutting machine.

Background

At present, when the traditional plasma cutting machine carries out latticed cutting, a pilot arc is established mainly by detecting that a main arc is extinguished, a stage that the electric arc disappears exists in the middle, the whole current output is not a continuous process, the metal with small grid holes is difficult to cut, high-frequency arc striking is needed for establishing the pilot arc, and the frequent high-frequency arc striking can cause damage to equipment and harm to human bodies.

Therefore, the problem of arc breakage exists in the process of switching the main arc into the maintenance arc in the traditional technical scheme.

Disclosure of Invention

The application aims to provide a cutting machine output control circuit, and aims to solve the problem that arc breakage exists in the process that a main arc is switched into a pilot arc in a traditional cutting machine.

A first aspect of an embodiment of the present application provides a cutting machine output control circuit, including:

the 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;

the output circuit is connected with the pulse width circuit and is configured to invert the pulse signal into first alternating current, convert the first alternating current into second alternating current and rectify the second alternating current to generate constant current and output the constant current to a main loop or a pilot arc loop;

the pilot arc circuit is connected with the anode of the output circuit and is configured to output the constant current as pilot arc current based on a pilot arc signal;

the alternating current feedback circuit is respectively connected with the output circuit and the pulse width circuit and is configured to detect the current of the first alternating current to generate the primary side detection current analog quantity; and

the main control circuit is respectively connected with the pulse width circuit and the pilot arc circuit and is configured to output the pilot arc signal when the pulse width signal is greater than or equal to a preset voltage and output the first current analog quantity according to a first current set value;

the main loop comprises the output circuit, a gun head and a ground clamp, the gun head is connected with the negative electrode of the output circuit, the ground clamp is connected with the positive electrode of the output circuit, and the ground clamp is configured to output the constant current as a main arc current; the pilot arc loop comprises the output circuit, the pilot arc circuit and the gun head, the gun head is respectively connected with the negative electrode of the output circuit and the pilot arc circuit, and the positive electrode of the output circuit is connected with the pilot arc circuit.

In one embodiment, the pulse width circuit comprises:

the pulse width modulation circuit is respectively connected with the main control circuit and the output circuit and is configured to output the pulse signal according to the first current analog quantity and the primary side detection current analog quantity; and

and the pulse width detection circuit is connected with the pulse width modulation circuit and the main control circuit and is configured to convert the pulse signal into the pulse width signal.

In one embodiment, the output circuit includes:

the inversion component is connected with the pulse width circuit and is configured to output a first alternating current according to the pulse signal;

the voltage transformation component is connected with the inversion component and is configured to convert the first alternating current into the second alternating current; and

and the rectifying component is connected with the voltage transformation component and is configured to rectify the second alternating voltage to generate the constant current.

In one embodiment, the cutter output control circuit further includes:

the output current feedback circuit is coupled with the main loop and connected with the main control circuit and is configured to detect the constant current of the main loop to generate a current sampling signal when the main loop is conducted;

the main control circuit is further configured to stop outputting the pilot arc signal and output the first current analog quantity according to a second current set value when the current sampling signal is larger than or equal to a first preset current.

In one embodiment, the pilot arc circuit comprises:

the pilot arc control circuit is connected with the main control circuit and is configured to output pilot arc control signals according to the pilot arc signals;

a switch assembly; and the constant current circuit is connected with the pilot arc control circuit and the output circuit and is configured to output the constant current as pilot arc current based on the pilot arc control signal.

In one embodiment, the pilot arc control circuit comprises 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 grounded capacitor, an optical coupler, 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 pole of the optical coupler is connected with the first end of the second resistor, the negative pole of the optical coupler is connected with a power supply ground, the first end of the resistor, the first end of the eighth resistor and the first end of the fourth resistor are connected together, 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 together, the second end of the eighth resistor is connected with the positive pole of the light emitting diode, the emitting electrode of the first field effect transistor, the emitting electrode of the second field effect transistor, the positive pole of the second diode, the negative pole 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 together, the second end of the fifth resistor is connected with the grid electrode of the third field effect transistor, the first end of the first resistor is connected with the grid electrode 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 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 negative electrode of the second diode are all connected with an internal power supply, the negative electrode of the light emitting diode, the collector of the second field effect transistor, the positive electrode of the third diode, the second end of the ninth resistor, the source of the third field effect transistor, the source of the fourth field effect transistor, 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 capacitor and the first end of the grounding capacitor are all connected with a power ground and are connected in common to form a first output end of a pilot arc control signal of the pilot arc control circuit, the drain electrode of the third field effect transistor, the drain electrode of the fourth field effect transistor, the second end of the first capacitor, the anode of the first diode and the second end of the third resistor are connected together to form a pilot arc control signal second output end of the pilot arc control circuit, the pilot arc control signal first output end and the pilot arc control signal second output end form a pilot arc control signal output end of the pilot arc control circuit, the first end of the second resistor is a pilot arc signal input end of the pilot arc control circuit, and the second end of the grounding capacitor is connected with a protective ground wire.

In one embodiment, the pulse width detection circuit comprises 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;

a first end of the tenth resistor, a first end of the eleventh resistor, a first end of the fifth capacitor, and a positive-phase input end of the first operational amplifier are commonly connected, an inverting input end of the first operational amplifier, an output end of the first operational amplifier, and a first end of the twelfth resistor are commonly connected, a second end of the twelfth resistor, a first end of the thirteenth resistor, a first end of the fourth capacitor, a negative electrode of the fourth diode, and a positive electrode of the fifth diode are commonly connected to form a pulse width signal output end of the pulse width detection circuit, a positive electrode of the fourth diode, a thirteenth resistor, a second end of the fourth capacitor, and a second end of the fifth capacitor are all connected to a power ground, a negative electrode of the fifth diode is connected to a first clamping voltage power supply, and a second end of the tenth resistor and a second end of the eleventh resistor form a pulse signal output end of the pulse width detection circuit And (4) entering the terminal.

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 thirty-third resistor, a thirty-eleventh 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 twelfth diode, an eleventh diode, a twelfth diode, a thirteenth diode, a fourteenth 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 positive phase 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 positive phase input end of the fifth operational amplifier is connected with 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, and the second end of the twenty-fifth resistor, A first end of the twenty-sixth resistor, a cathode of the twelfth diode, an anode of the eleventh diode, an anode of the twelfth diode, an inverting input of the sixth operational amplifier, and a first end of the thirty-first resistor are all connected, a second end of the twenty-sixth resistor is connected to the first end of the fourteenth capacitor, a cathode of the fifteenth diode, a second end of the fourteenth capacitor, an output of the sixth operational amplifier, and a first end of the twenty-seventh resistor are all connected, a second end of the twenty-seventh resistor, a first end of the twenty-eighth resistor, and an error amplification non-inverting input of the PWM modulation chip are all connected, a non-inverting input of the sixth operational amplifier is connected to the first end of the twenty-ninth resistor, a second end of the thirty-first resistor, and a first end of the fifteenth capacitor are all connected, a second end of the thirty-first resistor is connected to a cathode of the twelfth diode, an output end of the seventh operational amplifier, an inverting input end of the seventh operational amplifier and a cathode of the twelfth diode are connected in common, a non-inverting input end of the seventh operational amplifier, a first end of the thirty-third resistor and a first end of the thirty-fourth resistor are connected in common, a second end of the twelfth capacitor, a second end of the thirteenth capacitor, a second end of the thirty-second resistor, an anode of the twelfth diode, a cathode of the eleventh diode, a second end of the twenty-eighth resistor, a second end of the twenty-ninth resistor, a second end of the fifteenth capacitor, a second end of the thirty-third resistor, a first end of the sixteenth capacitor, an anode of the thirteenth diode and a cathode of the fourteenth diode are all connected to a power ground, the negative electrode of the thirteenth diode is connected with an internal power supply, the second end of the twenty-first resistor is a first current analog quantity input end 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 in common to form a primary side detection current analog quantity input end of the pulse width modulation circuit, and the first pulse output end of the PWM chip and the second pulse output end of the PWM chip form a pulse signal output end of the pulse width modulation circuit.

In one embodiment, the output current feedback circuit comprises 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;

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

A second aspect of the embodiments of the present application provides a cutting machine, which includes the gun head, the ground wire clamp for clamping a workpiece, and the cutting machine output control circuit according to any one of the above embodiments.

Compared with the prior art, the embodiment of the invention has the following beneficial effects: the cutting machine output control circuit identifies that the main circuit is about to break the arc before the main circuit breaks the arc by detecting the pulse width signal of the pulse width circuit, so that the constant current output by the output circuit is switched from the main circuit to the pilot arc circuit before the main circuit breaks the arc, and the condition that the high-frequency circuit needs to be opened again to start the arc again for establishing the pilot arc current after the main circuit breaks the arc is avoided.

Drawings

Fig. 1 is a schematic structural diagram of a first example of a cutter output control circuit provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a second example of a cutter output control circuit provided in an embodiment of the present application;

fig. 3 is a schematic structural diagram of a third example of a cutter output control circuit provided in an embodiment of the present application;

FIG. 4 is an exemplary circuit schematic diagram of a pilot arc control circuit provided by an embodiment of the present application;

FIG. 5 is an exemplary circuit schematic diagram of a pulse width detection circuit provided by an embodiment of the present application;

FIG. 6 is an exemplary circuit schematic diagram of a pulse width modulation circuit provided by an embodiment of the present application;

FIG. 7 is an exemplary circuit schematic of an output current feedback circuit provided by an embodiment of the present application;

fig. 8 is an exemplary circuit schematic diagram of a main control circuit provided in an embodiment of the present application.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

Fig. 1 shows a schematic structural diagram of a cutting machine output control circuit provided in a preferred embodiment of the present application, and for convenience of description, only the relevant parts of the present embodiment are shown, which are detailed as follows:

a chopper output control circuit includes a pulse width circuit 110, an output circuit 120, a pilot circuit 130, an alternating current feedback circuit 140, and a main control circuit 150.

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 convert the pulse signal into a pulse width signal.

And an output circuit 120 connected to the pulse width circuit 110 and configured to invert the pulse signal into a first alternating current, convert the first alternating current into a second alternating current, and rectify the second alternating current to generate a constant current and output the constant current to the main circuit or the pilot circuit.

And a pilot circuit 130 connected to the positive electrode of the output circuit 120 and configured to output the constant current as a pilot current based on the pilot signal.

An ac current feedback circuit 140 connected to the output circuit 120 and the pulse width circuit 110, respectively, and configured to detect a current of the first ac current to generate a primary side detection current analog; and

and the main control circuit 150 is respectively connected with the pulse width circuit 110 and the pilot arc circuit 130, and is configured to output a pilot arc signal when the pulse width signal is greater than or equal to a preset voltage and output a first current analog quantity according to a first current set value.

The main loop comprises an output circuit 120, a gun head 200 and a ground clamp 300, wherein the anode of the output circuit 120 is connected with the ground clamp 300, the cathode of the output circuit 120 is connected with the gun head 200, and the ground clamp 300 is configured to output a constant current as a main arc current; the pilot arc loop comprises an output circuit 120, a pilot arc circuit 130 and a gun head 200, wherein the positive pole of the output circuit 120 is connected with the pilot arc circuit 130, the pilot arc circuit 130 is connected with the gun head 200, and the gun head 200 is also connected with the negative pole of the output circuit 120.

In this embodiment, when the cutting machine is about to cut a blank space, the distance between the gun head 200 and the ground clamp 300 (or a workpiece connected to the ground clamp 300, hereinafter, for convenience of description, both are collectively referred to as the ground clamp 300) is gradually increased, the resistance value between the gun head 200 and the ground clamp 300 is gradually increased, so that the voltage value of the first alternating current output by the output circuit 120 is gradually increased, further the primary side detection current analog quantity of the first alternating current is gradually increased, further the pulse width signal of the pulse signal output by the pulse width circuit 110 is gradually increased, when the pulse width signal is greater than or equal to the preset voltage, the main control circuit 150 outputs the pilot signal to the pilot circuit 130 and outputs the first current analog quantity according to the preset first current setting value (pilot current setting value), 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 pilot arc, the pilot arc circuit 130 is conducted when a pilot arc signal is input and outputs a constant current to the pilot arc circuit as a pilot arc current, so that the output of the constant current is switched from the main circuit to the pilot arc circuit, after the pilot arc circuit is conducted, the main circuit is in a conducting state that the arc is not broken, and at the moment, a small part of the constant current exists in the main circuit, and the main circuit is broken along with the increase of the distance between the gun head 200 and the ground wire pliers 300. When the cutting machine output control circuit cuts a latticed workpiece, the constant current can be transferred from the main loop to the pilot arc loop before the main loop is disconnected, so that the constant current is prevented from being cut off, the workpiece with a small grid can be continuously cut all the time, and the pilot arc current output is controlled by the preset pilot arc current set value when the pilot arc loop is conducted, so that the consumption of a vulnerable part can be reduced; in addition, the cutter output control circuit of the present embodiment can recognize that the main circuit is about to be opened before the main circuit is opened by detecting the pulse width signal of the pulse width circuit 110, therefore, the constant current output by the output circuit 120 can be switched from the main circuit to the pilot arc circuit before the main circuit is broken, the high frequency is required to start the pilot arc circuit again after the main circuit is broken, in addition, because the constant current of the main loop is generated by pulse signal modulation, the trend of the change of the constant current of the main loop can be captured before the constant current actually changes by detecting the pulse width signal, so that the time for judging the main loop to be disconnected is quicker, therefore, arc breakage of the main circuit before the pilot arc circuit is not conducted can be better avoided, and the constant current can be accurately switched to the pilot arc circuit before the main circuit is disconnected.

The torch head 200 comprises an electrode and a nozzle, the nozzle is connected with the negative electrode of the output circuit 120, the electrode is connected with the positive electrode of the output circuit 120, the main circuit comprises the output circuit 120, the nozzle and the ground clamp 300, and the pilot circuit comprises the output circuit 120, the pilot circuit 130, the electrode and the nozzle. The nozzle and the electrode can be conducted in direct contact, and can also be conducted under the condition of pilot arc current breakdown medium. Referring to fig. 2, in one embodiment, the pulse width circuit 110 includes a pulse width modulation circuit 111 and a pulse width detection circuit 112.

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

And a pulse width detection circuit 112 connected to the pulse width modulation circuit 111 and the main control circuit 150 and configured to convert the pulse signal into a pulse width signal.

In this embodiment, the pulse width modulation circuit 111 outputs a pulse signal to control the output circuit 120 according to the first current analog quantity to be output from the main control circuit 150 and the primary side detection current analog quantity to be output from the output circuit 120, negative feedback regulation is formed to enable the constant current output from the output circuit 120 to be equal to a preset value, and the pulse width detection circuit 112 converts the pulse signal output from the pulse width modulation circuit 111 into a pulse width signal for monitoring the constant current output from the output circuit 120.

Referring to fig. 2, in one embodiment, the output circuit 120 includes an inverter 121, a transformer 122 and a rectifier 123.

And the inverter component 121 is connected with the pulse width circuit 110 and configured to output the first alternating current according to the pulse signal.

And the voltage transformation component 122 is connected with the inverter component 121 and configured to convert the first alternating current into a second alternating current.

And the rectifying component 123 is connected to the transforming component 122 and configured to rectify the second ac voltage to generate a constant current.

In this embodiment, the inverter module 121 inverts the dc power supply into a first ac power according to the pulse signal, then boosts the first ac power into a second ac power through the transformer module 122, and then the rectifier module 123 rectifies the second ac power to generate a constant current and outputs the constant current to the main circuit or the pilot arc circuit, which can improve the stability of the output constant current, and the ac current feedback circuit 140 is coupled to the primary coil of the transformer module 122, so that the ac current feedback circuit 140 can use a current transformer to collect the current of the first ac power to generate a primary detection current analog, and compared with using a current sensor, the device cost can be reduced.

The inverter module 121 may be an IGBT (Insulated Gate Bipolar Transistor) inverter module 121, the transformer module 122 may be a transformer, and the rectifier module 123 may be half-wave rectification, full-bridge rectification, and the like, where specific structures of the inverter module 121, the transformer module 122, and the rectifier module 123 are not limited herein.

Referring to fig. 3, in one embodiment, the output control circuit of the cutting machine further includes:

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

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

In this embodiment, the output current feedback circuit 160 is coupled to the main circuit, and outputs the collected current sampling signal of the constant current circuit flowing through the main circuit to the main control circuit 150 when the main circuit is turned on, the main control circuit 150 outputs a first current analog quantity according to a second current preset value (a main arc current set value) to control the pulse width circuit 110 when the current sampling signal is greater than or equal to a first preset current, when the pilot circuit is turned on, the gun head 200 is turned on with the ground clamp 300 when the distance between the gun head 200 and the ground clamp 300 is smaller than a certain value (the value depends on the voltage difference and the resistance between the gun head 200 and the ground clamp 300), so that the constant current of the main circuit rises, when the output current feedback circuit 160 collects the current sampling signal of the main circuit and is greater than or equal to the first preset current, the main control circuit 150 stops outputting the pilot signal and outputs the first current analog quantity according to a second current set value to control the output circuit 120, constant current is converted from output to a pilot arc loop to output to a main loop, so that the main loop can be supplied with the constant current in time when a workpiece is cut.

Referring to fig. 2, in one embodiment, the pilot circuit 130 includes:

and the pilot arc control circuit 131 is connected with the main control circuit 150 and is configured to output pilot arc control signals according to the pilot arc signals.

A switch assembly 132; and is connected to the pilot arc control circuit 131 and the output circuit 120, and is configured to output the constant current as a pilot arc current based on the pilot arc control signal.

In the present embodiment, the pilot control circuit 131 converts the pilot signal input from the main control circuit 150 into the pilot control signal for controlling the switching element 132 to be turned on, so that the output circuit 120 outputs the constant current as the pilot current through the switching element 132.

Referring to fig. 4, in an embodiment, the pilot arc 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 ground capacitor CC, an optical coupler 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;

the positive electrode of the optocoupler OU1 is connected with the first end of the second resistor R2, the negative electrode of the optocoupler OU1 is connected with the power ground, the first end of the resistor, the first end of the eighth resistor R8 and the first end of the fourth resistor R4 are connected in common, the second end of the fourth resistor R4, the base of the first field-effect tube Q1 and the base of the second field-effect tube Q2 are connected in common, the second end of the eighth resistor R8 is connected with the positive electrode of the light-emitting diode LED1, the emitter of the first field-effect tube Q1, the emitter of the second field-effect tube Q2, the positive electrode of the second 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 in common, the second end of the fifth resistor R5 is connected with the gate of the third field-effect tube Q3, the first end of the first resistor R1 is connected with the negative electrode of the fourth resistor Q4, the first end of the first resistor R5928 and the first end of the, A first end of a third capacitor C3, a first end of a third resistor R3 and a first end of a sixth resistor R6 are connected in common, a collector of the optocoupler OU1, a collector of the first field-effect transistor Q1 and a cathode of the second diode D2 are connected with an internal power supply, a cathode of the light-emitting diode LED1, a collector of the second field-effect transistor Q2, an anode of the third diode D3, a second end of the ninth resistor R9, a source of the third field-effect transistor Q3, a source of the fourth field-effect transistor Q4, a first end of the first capacitor C1, a second end of the second capacitor C2, a second end of the third capacitor C3, a second end of the sixth capacitor C6 and a first end of the grounding capacitor CC are connected with a power ground and connected in common to form a first output end of a pilot signal of the pilot arc control circuit 131, a drain of the third field-effect transistor Q3, a drain of the fourth field-effect transistor Q4, a first end of the first capacitor C3642, a first end of the first diode C1 and a first end of the pilot arc control signal control circuit 131 are connected in common to the first diode R3 The first output end of the pilot arc control signal and the second output end of the pilot arc control signal form a pilot arc control signal output end of the pilot arc control circuit 131, the first end of the second resistor R2 is a pilot arc signal input end of the pilot arc control circuit 131, and the second end of the grounding capacitor CC is connected with a protective ground wire.

Referring to fig. 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;

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

Referring to fig. 6, in an 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 thirty-third resistor R30, a thirty-eleventh resistor R31, a thirty-second resistor R32, a thirty-third resistor R33, a thirty-fourth resistor R33, a twelfth capacitor C33, a thirteenth capacitor C33, a fourteenth capacitor C33, a fifteenth capacitor C33, a sixteenth capacitor C33, a fourth operational amplifier U1 33, a fifth operational amplifier U1 33, a sixth operational amplifier U1 33, a seventh operational amplifier U1 33, a twelfth diode D33, an eleventh diode D33, a twelfth diode D33, a fourteenth diode U1D 33, a fourteenth diode U72, a fourteenth diode U33, a fourteenth diode 33, a PWM chip 33, and a PWM chip 33;

a first end of a twenty-first resistor R21, a first end of a twelfth capacitor C12 and a first end of a twenty-second resistor R22 are commonly connected, a second end of the twenty-second resistor R22, a first end of a thirteenth capacitor C13 and a non-inverting input terminal of a fourth operational amplifier U1D are commonly connected, an inverting input terminal of the fourth operational amplifier U1D, an output terminal of the fourth operational amplifier U1D and a first end of a twenty-third resistor R23 are commonly connected, a second end of a twenty-third resistor R23, a first end of a twenty-fourth resistor R24 and an inverting input terminal of a fifth operational amplifier U1E are commonly connected, a non-inverting input terminal of the fifth operational amplifier U1E is connected with a first end of a thirty-second resistor R32, an output terminal of the fifth operational amplifier U1E, a second end of the twenty-fourth resistor R24 and a first end of a twenty-fifth resistor R25 are commonly connected, a second end of the twenty-fifth resistor R25 and a second end of the sixth resistor R26 are commonly connected, A cathode of the twelfth diode D10, an anode of the eleventh diode D11, an anode of the twelfth diode D12, an inverting input terminal of the sixth operational amplifier U1F, and a first terminal of the thirty-first resistor R30 are commonly connected, a second terminal of the twenty-sixth resistor R26 is connected to a first terminal of the fourteenth capacitor C14, a cathode of the fifteenth diode, a second terminal of the fourteenth capacitor C14, an output terminal of the sixth operational amplifier U1F, and a first terminal of the twenty-seventh resistor R27 are commonly connected, a second terminal of the twenty-seventh resistor R27, a first terminal of the twenty-eighth resistor R28, and an error amplifying non-inverting input EA of the PWM modulating chip U2 are commonly connected, a non-inverting input terminal of the sixth operational amplifier is connected to a first terminal of the twenty-ninth resistor R29, a second terminal of the thirty resistor R30, a first terminal of the thirty-first resistor R31, and a first terminal of the fifteenth capacitor C15 are commonly connected, a cathode of the eleventh resistor R31 is connected to a cathode of the twelfth diode D12, an output end of a seventh operational amplifier U1G, an inverting input end of a seventh operational amplifier U1G and an anode of a twelfth diode D12 are commonly connected, a non-inverting input end of the seventh operational amplifier U1G, a first end of a thirty-third resistor R33 and a first end of a thirty-fourth resistor R34 are commonly connected, a second end of a twelfth capacitor C12, a second end of a thirteenth capacitor C13, a second end of a thirty-second resistor R32, an anode of a twelfth diode D10, a cathode of an eleventh diode D11, a second end of a twenty-eighth resistor R28, a second end of a twenty-ninth resistor R29, a second end of a fifteenth capacitor C15, a second end of a thirty-third resistor R33, a first end of a sixteenth capacitor C16, an anode of a thirteenth diode D13 and a cathode of a fourteenth diode D14 are all connected to a power supply ground, a cathode of the thirteenth diode D13 is connected to an internal power supply, a pulse current width modulation circuit 21 at a second end of a first resistor R21 is an analog current width input end of a first pulse current modulation circuit, the anode of the thirteenth diode D13, the cathode of the fourteenth diode D14, the second terminal of the sixteenth capacitor C16, and the second terminal of the thirty-fourth resistor R34 are commonly connected to form a primary side detection current analog input terminal of the pulse width modulation circuit 111, and 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 form a pulse signal output terminal of the pulse width modulation circuit 111.

Referring to fig. 7, in an 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 XH 1;

a signal terminal of the current sensor XH1, a positive terminal of the sixth diode D6, a negative terminal of the seventh diode D7, a first terminal of the fourteenth resistor R14, a first terminal of the eighth capacitor C8, and a positive-phase input terminal of the second operational amplifier U1B are commonly connected, a positive power terminal of the current sensor XH1 is commonly connected to the first terminal of the sixth capacitor C6 and the internal power supply, a negative power terminal of the current sensor XH1 is commonly connected to the first terminal of the seventh capacitor C7 and the internal negative power supply, an inverting input terminal of the second operational amplifier U1B, an output terminal of the second operational amplifier U1B, and a first terminal of the fifteenth resistor R15, a second terminal of the fifteenth resistor R15, a first terminal of the sixteenth resistor R16, and a first terminal of the tenth capacitor C10 are commonly connected, a second terminal of the sixteenth resistor R16, a first terminal of the ninth capacitor C9, and a positive-phase input terminal of the third operational amplifier U1C are commonly connected, and a positive-phase input terminal of the third operational amplifier U1C is commonly connected to the inverting, A first end of a seventeenth resistor R17 and a first end of an eighteenth resistor R18 are commonly connected, a second end of the eighteenth resistor R18, an output end of a third operational amplifier U1C, a first end of a nineteenth resistor R19 and a second end of a tenth capacitor C10 are commonly connected, a second end of a nineteenth resistor R19, an anode of an eighth diode D8, a cathode of a ninth diode D9, a first end of a twentieth resistor R20 and a first end of an eleventh capacitor C11 are commonly connected to form a current sampling signal output end of the output current feedback circuit 160, a ground end of a current sensor XH1, a second end of a sixth capacitor C6, a second end of a seventh capacitor C7, an anode of a seventh diode D7, a second end of an eighth capacitor C8, a second end of a ninth capacitor C9, a second end of a seventeenth resistor R17, an anode of a ninth diode D9, a second end of a twentieth resistor R20 and a second end of an 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 an 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 collecting end of the output current feedback circuit 160.

Referring to fig. 8, the main control circuit 150 includes a current control chip U3, a first analog-to-digital conversion input PA1 of the current control chip U3 is a pulse width signal input of the main control circuit 150, a second analog-to-digital conversion input PA2 of the current control chip U3 is a current sampling signal input of the main control circuit 150, a universal input/output I/O of the current control chip U3 is a pilot arc signal output of the main control circuit 150, and an analog output OUT of the current control chip U3 is a first current analog output of the main control circuit 150.

The exemplary circuit schematics shown in fig. 4 to 8 are explained below in connection with the working principle. An analog quantity output end OUT of the current control chip U3 outputs a first current analog quantity according to a second current preset value, the first current analog quantity sequentially passes through a twenty-first resistor R21, a twenty-second resistor R22, a fourth operational amplifier U1D, a twenty-third resistor R23, a fifth operational amplifier U1E and a twenty-fifth resistor R25 and is input to an inverted input end of a sixth operational amplifier U1F, a primary side detection current analog quantity sequentially passes through a thirty-fourth resistor R34, a seventh operational amplifier U1G, a twelfth diode D12, a thirty-first resistor R31 and a thirty-third resistor R30 and is input to an inverted input end of the sixth operational amplifier U1F, the sixth operational amplifier U1F amplifies errors of the first current analog quantity and the primary side detection current analog quantity and then inputs the errors to an error amplification equidirectional input end of a PWM modulation chip U2 through a twenty-seventh resistor R27 and outputs pulse signals of a PWM output end OUT2 of a first pulse modulation chip U2 and a PWM chip 2, a pulse signal output by a first pulse output end OUT1 is input to a non-inverting input end of a first operational amplifier U1A through a tenth resistor R10, a pulse signal output by a second pulse output end OUT2 is input to a non-inverting input end of the first operational amplifier U1A through an eleventh resistor R11, the first operational amplifier U1A amplifies the pulse signal, then the pulse signal is filtered by a twelfth resistor R12, a thirteenth resistor R13 and a fourth capacitor C4 to form a pulse width signal, the pulse width signal is input to a current control chip U3 through a first analog-to-digital conversion input end PA1 of a current control chip U3, the current control chip U3 compares the pulse width signal with a preset voltage, when the pulse width signal is greater than or equal to the preset voltage, a universal input/O output end I/O of the current control chip U3 outputs a pilot arc signal and an analog quantity output end OUT outputs a first current analog quantity according to a first current set value, the pilot arc signal is input to an optical coupler OU1 through a second resistor R2, the optical coupler OU1 is conducted, an emitter of the optical coupler OU1 outputs high level, the high level enables the first field effect tube Q1 and the second field effect tube Q2 to be conducted, and therefore the third field effect tube Q3 and the fourth field effect tube Q4 are conducted, thereby making the pilot arc control circuit 131 output high level to control the switch component 132 to conduct so as to make the pilot arc loop conduct, then, a constant current of the main loop collected by the current sensor XH1 is output through a signal end of the current sensor XH1, the constant current is converted into a current sampling signal under the action of a second operational amplifier U1B, a fifteenth resistor R15, a sixteenth resistor R16, a third operational amplifier U1C and a nineteenth resistor R19 in sequence and is output to a second analog-to-digital conversion input end PA2 of the current control chip U3, and when the current sampling signal is greater than or equal to a first preset current, the current control chip U3 stops outputting the pilot arc signal and outputs the first current analog quantity according to a second current set value.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims

1. A cutter output control circuit, comprising:

the pilot arc circuit is connected with the output circuit and is configured to output the constant current as pilot arc current based on a pilot arc signal;

2. The cutter output control circuit according to claim 1, wherein the pulse width circuit comprises:

3. The cutter output control circuit according to claim 1, wherein the output circuit comprises:

4. The cutter output control circuit according to claim 1, characterized by further comprising:

5. The cutter output control circuit according to claim 1, wherein the pilot circuit comprises:

6. The cutting machine output control circuit according to claim 5, wherein the pilot arc control circuit comprises 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 grounded capacitor, an optical coupler, 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;

7. The cutter output control circuit according to claim 2, wherein 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;

8. The cutting machine output control circuit according to claim 2, wherein the pulse width modulation circuit comprises 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 thirty-third resistor, a thirty-eleventh 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 twelfth diode, an eleventh diode, a twelfth diode, a thirteenth diode, a fourteenth diode, and a PWM modulation chip;

9. The cutter output control circuit according to claim 4, wherein the output current feedback circuit comprises 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;

10. A cutting machine comprising the torch head, the ground wire clamp for clamping a workpiece, and the output control circuit of the cutting machine according to any one of claims 1 to 9.