Plasma cutting alternating current control maintenance circuit

Abstract

The utility model discloses a plasma cutting alternating current control maintenance circuit, which relates to the field of on-off control, and comprises a three-phase electric processing module, a voltage conversion boosting module, an alternating current control module, an alternating current control module, an alternating current control module and an alternating current control module, wherein the three-phase electric processing module is used for converting three-phase alternating current into direct current and outputting the direct current to the voltage conversion boosting module; the voltage conversion boosting module is used for converting direct current into alternating current, boosting the alternating current and outputting the alternating current to the rectification filtering output module and the on-off control module; the on-off control module is used for outputting the input alternating current to the arc striking output module after passing through the switch and the RC buffer circuit; compared with the prior art, the utility model has the beneficial effects that the work of the arc striking output module is limited by the on-off control module, the on-off control module outputs the input alternating current to the arc striking output module after passing through the switch and the RC buffer circuit, and the on-off of the plasma machine is controlled through the switch; and the RC buffer circuit absorbs transient high-voltage energy generated during disconnection, so that an arc discharge phenomenon is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to on-off control field, specifically a kind of plasma cutting AC control maintenance circuit. BACKGROUND

[0002] The direct current arc phenomenon that appears in the process of direct current on-off control of plasma machine is that arc is forced to be lengthened and cannot be stably maintained due to sudden interruption or fluctuation of current. The specific reason is that when cathode and anode contact, large current passes through the contact point to form arc, and ionized air generates high-temperature plasma. At this time, the arc is stretched to the outside of the nozzle under the action of the magnetic field, forming a stable plasma flow. When the direct current is suddenly interrupted, the arc energy cannot be continuously supplied, resulting in a sharp drop in the degree of plasma ionization, and the arc is "broken" or lengthened, forming an unstable arc breaking state. If the current is not restored in time, the arc may not be re-established.

[0003] If the direct current arc phenomenon occurs in the on-off control process of plasma machine, the high temperature (3000-7000 ℃) generated by direct current arc will directly ablate key components such as electrodes and nozzles, resulting in a significant reduction in the service life of the equipment (such as a possible 40% reduction in the service life of the anode). When the arc continues to burn, the high temperature may ignite the surrounding combustible materials (such as cable insulation or equipment shell), therefore, it is necessary to avoid the occurrence of direct current arc phenomenon in plasma machine as much as possible. SUMMARY

[0004] The utility model aims at providing a kind of plasma cutting AC control maintenance circuit to solve the problems raised in the above background.

[0005] To achieve the above purpose, the utility model provides the following technical scheme:

[0006] A kind of plasma cutting AC control maintenance circuit, comprising:

[0007] Three-phase electric processing module is used to convert three-phase alternating current into direct current, and output to voltage conversion boost module;

[0008] Voltage conversion boost module is used to convert direct current into alternating current, and output to rectification filter output module and on-off control module after boosting;

[0009] On-off control module is used to output to arc starting output module after input alternating current passes through switch and RC buffer circuit;

[0010] Rectification filter output module is used to output to arc starting output module after converting input alternating current into direct current;

[0011] Arc starting output module is used to generate arc after current input;

[0012] The output end of the three-phase electric processing module is connected with the input end of the voltage conversion and boosting module, the output end of the voltage conversion and boosting module is connected with the input end of the on-off control module and the input end of the rectification and filtering output module, the output end of the on-off control module is connected with the first input end of the arc striking output module, and the output end of the rectification and filtering output module is connected with the second input end of the arc striking output module.

[0013] As a further scheme of the utility model: the three-phase electric processing module includes circuit breaker QF1, common mode choke L, rectifier D1, resistance R1, capacitor C9, the input end of circuit breaker QF1 leads into fire line U, fire line V, fire line W, the output end of circuit breaker QF1 is connected with the input end of common mode choke L, the output end of common mode choke L is connected with the input end of rectifier D1, the output end of rectifier D1 is connected with one end of resistance R1, one end of capacitor C9 and the input end of voltage conversion and boosting module, and the output end of rectifier D1 is connected with the other end of resistance R1, the other end of capacitor C9 and the input end of voltage conversion and boosting module.

[0014] As a further scheme of the utility model: the voltage conversion and boosting module includes direct current to alternating current unit V1 and transformer W, the input end of direct current to alternating current unit V1 is connected with the output end of three-phase electric processing module, the output end of direct current to alternating current unit V1 is connected with the input end of transformer W, and the output end of transformer W is connected with the input end of on-off control module and the input end of rectification and filtering output module.

[0015] As a further scheme of the utility model: the on-off control module includes switch J3B, switch J4B, resistance R3, resistance R4, diode D7, diode D8, capacitor C12 and capacitor C13, one end of switch J3B is connected with one end of the output end of transformer W, one end of switch J4B is connected with the other end of the output end of transformer W, the other end of switch J3B is connected with the positive electrode of diode D7 and one end of resistance R3, the other end of resistance R3 is connected with one end of capacitor C12, the other end of capacitor C12 is connected with the negative electrode of diode D7, the first input end of arc striking output module, the negative electrode of diode D8 and one end of capacitor C13, the other end of capacitor C13 is connected with one end of resistance R4, and the other end of resistance R4 is connected with the positive electrode of diode D8 and the other end of switch J4B.

[0016] As a further scheme of the utility model: the rectification filter output module includes diode D2, diode D4, diode D5, diode D6, capacitor C11, resistance R2, the positive pole of diode D2 is connected with the negative pole of diode D5, the output end one end of transformer W, the positive pole of diode D4 is connected with the negative pole of diode D6, the output end other end of transformer W, the negative pole of diode D2 is connected with the negative pole of diode D4, one end of capacitor C11, the second input end of arc striking output module, the positive pole of diode D5 is connected with the positive pole of diode D6, one end of resistance R2, one end of inductance L5, the other end of resistance R2 is connected with the other end of capacitor C11, the other end of inductance L5 is connected with the second input end of arc striking output module.

[0017] Compared with the prior art, the utility model has the advantages that: the arc striking output module is limited by the on-off control module, the on-off control module outputs the input alternating current to the arc striking output module after the alternating current passes through the switch and RC buffer circuit, the switch controls the on-off of the plasma machine, and the RC buffer circuit absorbs the transient high voltage energy generated when the switch is turned off, so that the arc phenomenon is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a kind of circuit diagram of plasma cutting AC control maintenance circuit. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Apparently, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model.

[0020] Please refer to Figure 1 A kind of plasma cutting AC control maintenance circuit, comprising:

[0021] Three-phase electric processing module is used to convert three-phase alternating current into direct current, and output to voltage conversion boost module;

[0022] Voltage conversion boost module is used to convert direct current into alternating current, and output to rectification filter output module and on-off control module after boosting;

[0023] On-off control module is used to output input alternating current to arc striking output module after the alternating current passes through switch and RC buffer circuit;

[0024] Rectification filter output module is used to convert input alternating current into direct current and output to arc striking output module;

[0025] The arc striking output module is used for generating an arc after current input;

[0026] The output end of the three-phase electric processing module is connected with the input end of the voltage conversion and boosting module, the output end of the voltage conversion and boosting module is connected with the input end of the on-off control module and the input end of the rectification and filtering output module, the output end of the on-off control module is connected with the first input end of the arc striking output module, and the output end of the rectification and filtering output module is connected with the second input end of the arc striking output module.

[0027] In specific embodiments: the arc striking based on the working of the plasma machine is a common technology, so the related control feedback technology of the main control board is not introduced. Figure 1 In this embodiment: please refer to

[0028] In this embodiment: please refer to Figure 1 The three-phase electric processing module comprises a circuit breaker QF1, a common-mode choke L, a rectifier D1, a resistor R1 and a capacitor C9. The input end of the circuit breaker QF1 is connected with live wires U, V and W. The output end of the circuit breaker QF1 is connected with the input end of the common-mode choke L. The output end of the common-mode choke L is connected with the input end of the rectifier D1. The positive output end of the rectifier D1 is connected with one end of the resistor R1, one end of the capacitor C9 and the input end of the voltage conversion and boosting module. The negative output end of the rectifier D1 is connected with the other end of the resistor R1, the other end of the capacitor C9 and the input end of the voltage conversion and boosting module.

[0029] Three-phase alternating current is introduced through the live wires U, V and W, and is output to the rectifier D1 after passing through the circuit breaker QF1, and is converted into direct current. After being filtered by the resistor R1 and the capacitor C9, the direct current becomes stable.

[0030] In this embodiment: please refer to Figure 1 The voltage conversion and boosting module comprises a direct current to alternating current unit V1 and a transformer W. The input end of the direct current to alternating current unit V1 is connected with the output end of the three-phase electric processing module. The output end of the direct current to alternating current unit V1 is connected with the input end of the transformer W. The output end of the transformer W is connected with the input end of the on-off control module and the input end of the rectification and filtering output module.

[0031] Figure 1 The direct current to alternating current unit V1 can be regarded as being composed of four IGBT tubes. By controlling the on-off of the IGBT tubes, the input direct current is converted into alternating current, which is output to the transformer W. After being boosted by the transformer W, the alternating current is output to the on-off control module and the rectification and filtering output module.

[0032] In this embodiment: please refer to Figure 1The on-off control module includes switches J3B and J4B, resistors R3 and R4, diodes D7 and D8, and capacitors C12 and C13. One end of the switch J3B is connected to one end of the output end of the transformer W, one end of the switch J4B is connected to the other end of the output end of the transformer W, the other end of the switch J3B is connected to the positive electrode of the diode D7 and one end of the resistor R3, the other end of the resistor R3 is connected to one end of the capacitor C12, the other end of the capacitor C12 is connected to the negative electrode of the diode D7, the first input end of the arc striking output module, the negative electrode of the diode D8, and one end of the capacitor C13, the other end of the capacitor C13 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the positive electrode of the diode D8 and the other end of the switch J4B.

[0033] The resistor R3 and the capacitor C12 form an RC buffer circuit, and the resistor R4 and the capacitor C13 form an RC buffer circuit. The RC buffer circuit absorbs the transient high-voltage energy generated when the switches J3B and J4B are disconnected, thereby avoiding the occurrence of arc drawing. The diodes D7 and D8 in parallel with the buffer circuit are used to provide a fast discharge path. When the plasma machine is rapidly turned on and off, the charges stored in the capacitors C12 and C13 need to be discharged in time. The diodes D7 and D8 provide a low-impedance discharge path (through the forward conduction of the diodes) for the capacitors C12 and C13, thereby avoiding charge residue.

[0034] In the embodiment, please refer to Figure 1 The rectification and filtering output module includes diodes D2, D4, D5, and D6, a capacitor C11, and a resistor R2. The positive electrode of the diode D2 is connected to the negative electrode of the diode D5 and one end of the output end of the transformer W, the positive electrode of the diode D4 is connected to the negative electrode of the diode D6 and the other end of the output end of the transformer W, the negative electrode of the diode D2 is connected to the negative electrode of the diode D4, one end of the capacitor C11, and the second input end of the arc striking output module, the positive electrode of the diode D5 is connected to the positive electrode of the diode D6, one end of the resistor R2, and one end of the inductor L5, the other end of the resistor R2 is connected to the other end of the capacitor C11, and the other end of the inductor L5 is connected to the second input end of the arc striking output module.

[0035] The alternating current is converted into direct current by the diodes D2, D4, D5, and D6, and is filtered by the capacitor C11 and the resistor R2 to become stable direct current, which is output to the subsequent circuit.

[0036] The working principle of the utility model is: three-phase electric processing module is used for converting three-phase alternating current into direct current, and outputs to voltage conversion boost module; voltage conversion boost module is used for converting direct current into alternating current, and outputs to rectification filtering output module and on-off control module after boosting; on-off control module is used for outputting input alternating current to arc striking output module after switching and RC buffer circuit; rectification filtering output module is used for outputting input alternating current to arc striking output module after converting into direct current; arc striking output module is used for generating electric arc after current input.

[0037] It is apparent for those skilled in the art that the utility model is not limited to the details of the above-mentioned exemplary embodiments, and the utility model can be realized in other specific forms without departing from the spirit or essential characteristics of the utility model.

[0038] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the specification is described in this way only for clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A plasma cutting AC control and maintenance circuit, characterized in that, The plasma cutting AC control and maintenance circuit includes: The three-phase power processing module is used to convert three-phase AC power into DC power and output it to the voltage conversion and boost module; The voltage conversion and boost module is used to convert DC power into AC power, and after boosting, output it to the rectifier and filter output module and the on / off control module. The on / off control module is used to output the input AC power to the arc ignition output module after passing through a switch and an RC buffer circuit. The rectifier and filter output module is used to convert the input AC power into DC power and output it to the arc ignition output module. Arc ignition output module, used to generate an electric arc after current input; The output of the three-phase power processing module is connected to the input of the voltage conversion and boost module. The output of the voltage conversion and boost module is connected to the input of the on / off control module and the input of the rectifier and filter output module. The output of the on / off control module is connected to the first input of the arc ignition output module. The output of the rectifier and filter output module is connected to the second input of the arc ignition output module.

2. The plasma cutting AC control and maintenance circuit according to claim 1, characterized in that, The three-phase power processing module includes a circuit breaker QF1, a common-mode choke L, a rectifier D1, a resistor R1, and a capacitor C9. The input terminals of the circuit breaker QF1 are connected to live wires U, V, and W. The output terminal of the circuit breaker QF1 is connected to the input terminal of the common-mode choke L, which in turn is connected to the input terminal of the rectifier D1. The positive terminal of the rectifier D1's output terminal is connected to one end of the resistor R1, one end of the capacitor C9, and the input terminal of the voltage conversion and boost module. The negative terminal of the rectifier D1's output terminal is connected to the other end of the resistor R1, the other end of the capacitor C9, and the input terminal of the voltage conversion and boost module.

3. The plasma cutting AC control and maintenance circuit according to claim 1, characterized in that, The voltage conversion and boost module includes a DC-to-AC unit V1 and a transformer W. The input terminal of the DC-to-AC unit V1 is connected to the output terminal of the three-phase power processing module, and the output terminal of the DC-to-AC unit V1 is connected to the input terminal of the transformer W. The output terminal of the transformer W is connected to the input terminal of the on / off control module and the input terminal of the rectifier and filter output module.

4. The plasma cutting AC control and maintenance circuit according to claim 3, characterized in that, The on / off control module includes switch J3B, switch J4B, resistor R3, resistor R4, diode D7, diode D8, capacitor C12, and capacitor C13. One end of switch J3B is connected to one output terminal of transformer W, one end of switch J4B is connected to the other output terminal of transformer W, the other end of switch J3B is connected to the positive terminal of diode D7, one end of resistor R3, the other end of resistor R3 is connected to one end of capacitor C12, the other end of capacitor C12 is connected to the negative terminal of diode D7, the first input terminal of the arc ignition output module, the negative terminal of diode D8, one end of capacitor C13, the other end of capacitor C13 is connected to one end of resistor R4, the other end of resistor R4 is connected to the positive terminal of diode D8, and the other end of switch J4B.

5. The plasma cutting AC control and maintenance circuit according to claim 3, characterized in that, The rectifier and filter output module includes diodes D2, D4, D5, and D6, capacitor C11, and resistor R2. The anode of diode D2 is connected to the cathode of diode D5 and one end of the output terminal of transformer W. The anode of diode D4 is connected to the cathode of diode D6 and the other end of the output terminal of transformer W. The cathode of diode D2 is connected to the cathode of diode D4, one end of capacitor C11, and the second input terminal of the arc-starting output module. The anode of diode D5 is connected to the anode of diode D6, one end of resistor R2, and one end of inductor L5. The other end of resistor R2 is connected to the other end of capacitor C11, and the other end of inductor L5 is connected to the second input terminal of the arc-starting output module.

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