Plasma welding non-transferred arc power supply circuit

Abstract

The utility model relates to the technical field of welding, in particular to a plasma welding non-transferred arc power supply circuit. The system comprises a rectification unit D1, an inverter circuit V1, a first transformer T1, a control unit and a second transformer T2. The rectification unit D1 is a three-phase rectification unit D1 and is used for realizing rectification of a three-phase input power supply. The no-load voltage of the power supply circuit is greater than 80V, and the requirements that the constant current inflection point voltage is greater than 35V and the ripple coefficient is small when the load is 30A are met.

Description

Technical Field

[0001] The utility model relates to the technical field of welding, in particular to a plasma welding non-transferred arc power supply circuit. Background Art

[0002] In the welding field, when using a mixed ion gas of 5% H2 and 95% Ar, the ionization voltage of the mixed gas is higher than that of pure argon, requiring a no-load voltage of at least 80V at arc initiation. Therefore, the plasma welding non-transferred arc power supply must have a no-load voltage greater than 80V. Main arc initiation requires a large plasma gas flow rate to propel the non-transferred arc onto the base material. This increases the arc length, requiring the plasma welding non-transferred arc power supply to have a relatively high load voltage. The constant current knee voltage at a load of 30A must be greater than 35V, and the ripple factor must be low.

[0003] At present, most plasma welding non-transferred arc power supplies are powered by single-phase power supplies. The no-load voltage cannot reach above 80V, nor can it meet the requirements of a constant current inflection point voltage greater than 35V when the load is 30A and a small ripple coefficient. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a plasma welding non-transferred arc power supply circuit, the no-load voltage of the power supply circuit is greater than 80V, and the constant current inflection point voltage is greater than 35V when the load is 30A, and the ripple coefficient is small.

[0005] To solve the above problems, the following technical solutions are provided:

[0006] The utility model discloses a plasma welding non-transferred arc power supply circuit, comprising:

[0007] The rectifier unit D1 is used to connect to the input power supply and rectify the input power supply before outputting it;

[0008] The inverter circuit V1 is adapted to be connected to the rectifier unit D1 and is used to invert the rectified input power to form an alternating current of a required frequency;

[0009] A first transformer T1, the input end of the transformer is adaptively connected to the inverter circuit V1, and is used to convert the AC voltage into a required voltage; the output end of the transformer is adaptively connected to the positive port and the negative port of the plasma welding non-transferred arc;

[0010] A control unit is adapted to be connected to the inverter and is used to control the conduction or stop of the power tube in the inverter;

[0011] Its characteristic is that the rectifier unit D1 is a three-phase rectifier unit D1 so as to realize the rectification of the three-phase input power supply; the input ends of the U phase, V phase and W phase of the three-phase rectifier unit D1 are all provided with switches.

[0012] The control unit comprises a driving board and a main controller, the main controller is adaptively connected with the driving board, and is used for controlling the driving board to start or stop, and the driving board is adaptively connected with the inverter, and is used for controlling the inverter to turn on or stop the power tube.

[0013] The scheme further comprises a second transformer T2, which is adaptively connected with the input power supply, and is used for converting three-phase points of the input power supply into working power of the driving board and the main controller for use of the driving board and the main controller.

[0014] One end of a fuse F1 is connected with a U phase of the input power supply, and the other end of the fuse F1 is connected with a 380V input end of the second transformer T2; a V phase of the input power supply is connected with one end of a capacitor C2 and a 0V input end of the second transformer T2 respectively, one end of the capacitor C2 is connected with the other end of the capacitor C2, and the other end of the capacitor C2 is connected with the U phase of the input power supply; and a W phase of the input power supply is connected with one end of a capacitor C1, and the other end of the capacitor C1 is connected with one end of a capacitor C3 connected with the capacitor C2.

[0015] The positive output end of the rectifier unit D1 is connected with one end of a resistor R1 and one end of a capacitor C9 respectively, and the other end of the resistor R1 and the other end of the capacitor C9 are both connected with the negative output end of the rectifier unit D1.

[0016] The positive end of the non-transferred arc of the plasma welding is connected with a variable inductor H

[0017] The above scheme has the following advantages:

[0018] The rectifier unit D1 of the plasma welding non-transferred arc power supply circuit is a three-phase rectifier unit D1, so as to realize rectification of a three-phase input power supply, and the input ends of a U phase, a V phase and a W phase of the three-phase rectifier unit D1 are all provided with switches. The plasma welding non-transferred arc power supply circuit rectifies the three-phase input power supply, so that the no-load voltage of the power supply circuit is greater than 80V, and the constant current inflection point voltage when the load is 30A is greater than 35V. Meanwhile, the three-phase rectification can reduce the ripple coefficient, the influence of the power grid fluctuation is small, and thus the demand of small ripple coefficient is met. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a wiring schematic diagram of the plasma welding non-transferred arc power supply circuit of the utility model. DETAILED DESCRIPTION

[0020] The utility model will be further described in detail in combination with the drawings and embodiments.

[0021] As Figure 1As shown in the utility model, the non-transferred arc power supply circuit of the plasma welding includes: rectifier unit D1, inverter circuit V1, first transformer T1, control unit and second transformer T2. The rectifier unit D1 is a three-phase rectifier unit D1, which is used for realizing the rectification of a three-phase input power supply, and is connected with the input power supply to output after rectifying the input power supply. The input power supply is a three-phase rectifier unit D1, and the input ends of the U phase, V phase and W phase of the three-phase rectifier unit D1 are all provided with switches. The inverter circuit V1 is adaptively connected with the rectifier unit D1 to invert the rectified input power supply into alternating current with a required frequency. The input end of the first transformer T1 is adaptively connected with the inverter circuit V1, which is used for converting the alternating current voltage into a required voltage. The output end of the transformer is adaptively connected with the positive and negative ports of the non-transferred arc of the plasma welding, and the positive port of the non-transferred arc of the plasma welding is connected with a reactor H. The control unit is adaptively connected with the inverter to control the conduction or stop of the power tube in the inverter. The second transformer T2 is connected with the input power supply to adaptively convert the three-phase points of the input power supply into working power for the driving board and the main controller.

[0022] As shown in the utility model, Figure 1 In the embodiment, the control unit includes a driving board and a main controller, the main controller is adaptively connected with the driving board to control the start or stop of the driving board, and the driving board is adaptively connected with the inverter to control the conduction or stop of the power tube in the inverter.

[0023] As shown in the utility model, Figure 1 In the embodiment, the U phase of the input power supply is connected with one end of the fuse F1, the other end of the fuse F1 is connected with the 380V input end of the second transformer T2. The V phase of the input power supply is connected with one end of the capacitor C2 and the 0V input end of the second transformer T2 respectively, the other end of the capacitor C2 is connected with one end of the capacitor C2, and the other end of the capacitor C2 is connected with the U phase of the input power supply. The W phase of the input power supply is connected with one end of the capacitor C1, and the other end of the capacitor C1 is connected with one end of the capacitor C3 connected with the capacitor C2.

[0024] As shown in the utility model, Figure 1 In the embodiment, the positive output end of the rectifier unit D1 is connected with one end of the resistor R1 and one end of the capacitor C9 respectively, and the other end of the resistor R1 and the other end of the capacitor C9 are both connected with the negative output end of the rectifier unit D1.

[0025] The utility model discloses plasma welding non -transfer arc power supply circuit carries out rectification to three -phase input power supply, and three -phase rectification can reduce ripple coefficient, and the influence of receiving power grid fluctuation is little. Through the first transformer T1 setting no -load power 90V. The inflection point voltage of power output 30A constant current time is greater than 35V. Customize reactor, guarantee the balance between the current rise rate when arc drawing and the ripple coefficient when load 35V. Through the reactor guarantee the balance between the current rise rate when arc drawing and the ripple coefficient when load 35V.

Claims

1. A non-transferred arc power supply circuit for plasma welding, comprising: a rectifier unit D1 connected to an input power supply and outputting after rectifying the input power supply; an inverter circuit V1 connected to the rectifier unit D1 and used for inverting the rectified input power supply into alternating current of a required frequency; a first transformer T1, the input end of which is connected to the inverter circuit V1 and used for converting the alternating current voltage into a required voltage; the output end of the transformer being connected to a positive electrode port and a negative electrode port of the non-transferred arc power supply circuit for plasma welding; a control unit connected to the inverter and used for controlling the conduction or stop of power tubes in the inverter; characterized in that the rectifier unit D1 is a three-phase rectifier unit D1 so as to realize the rectification of a three-phase input power supply; the input end of each of the U phase, V phase and W phase of the three-phase rectifier unit D1 is provided with a switch.

2. The non-transferred arc power supply circuit for plasma welding of claim 1, wherein, the control unit comprises a drive board and a main controller, the main controller being connected to the drive board and used for controlling the start or stop of the drive board, and the drive board being connected to the inverter and used for controlling the conduction or stop of the power tubes in the inverter.

3. The non-transferred arc power supply circuit for plasma welding of claim 2, wherein, a second transformer T2 is further included and used for being connected to the input power supply and converting the three-phase point of the input power supply into working power for the drive board and the main controller.

4. The non-transferred arc power supply circuit for plasma welding of claim 3, wherein, one end of the U phase of the input power supply is connected to a fuse F1, the other end of the fuse F1 is connected to the 380V input end of the second transformer T2; the V phase of the input power supply is connected to one end of a capacitor C2 and the 0V input end of the second transformer T2 respectively, the other end of the capacitor C2 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the U phase of the input power supply; the W phase of the input power supply is connected to one end of a capacitor C1, and the other end of the capacitor C1 is connected to one end of a capacitor C2 connected to a capacitor C3.

5. The non-transferred arc power supply circuit for plasma welding of claim 1, wherein, the positive output end of the rectifier unit D1 is connected to one end of a resistor R1 and one end of a capacitor C9 respectively, and the other end of the resistor R1 and the other end of the capacitor C9 are both connected to the negative output end of the rectifier unit D1.

6. The non-transferred arc power supply circuit for plasma welding of claim 1, wherein, the positive electrode port of the non-transferred arc power supply circuit for plasma welding is connected to a varistor H.

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