Arc welding with synchronized high frequency assist arc initiation

Patent metadata

Field	Value
Publication number	US-10376980-B2
Application number	US-201313789788-A
Country	US
Kind code	B2
Filing date	Mar 8, 2013
Priority date	Mar 8, 2013
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A method of and system for controlling high frequency arc initiation in a power supply is provided. The power supply includes an output circuit that outputs at least one of a voltage waveform and a current waveform. High frequency, high voltage pulses are induced across a gap between an electrode and a workpiece to create an arc. The method and system further include monitoring at least one of a voltage reading and a current reading across the gap to determine a condition of the arc and controlling the high frequency, high voltage pulses based on the condition of the arc and the type of process, which can be, e.g., SMAW, GTAW, GMAW, FCAW, etc.

First claim

I claim:

1. A power supply with synchronized high frequency arc assist, said power supply comprising:
an output circuit that is configured to output at least one of a voltage waveform and a current waveform to a torch;
an ignition circuit that is connected to the torch between the output circuit and the torch and that is configured to initiate high frequency, high voltage pulses across a gap, wherein said high frequency, high voltage pulses are superimposed on said at least one of a voltage waveform and a current waveform;
a monitoring circuit that is configured to monitor at least one of a voltage across said gap and a current passing through said gap; and
a controller operatively connected to said output circuit to regulate said at least one of a voltage waveform and a current waveform based on a desired process,
wherein said controller is configured to select an ignition operation for said high frequency, high voltage pulses based on said desired process,
wherein said controller is operatively connected to said monitoring circuit and is configured to determine a condition of an arc across said gap based on said at least one of said voltage across said gap and said current passing through said gap,
wherein said controller is configured to control said ignition circuit based on said selected ignition operation and said arc condition,
wherein the output circuit includes both a center-tapped output choke and a superposition circuit for re-igniting the arc, and the ignition circuit is connected between a center tap of the output choke and the torch,
wherein said controller is configured to activate said high frequency, high voltage pulses after determining that said condition of said arc is off based on said at least one of said voltage across said gap and said current passing through said gap being at a respective predetermined value for a predetermined period of time, and
wherein said predetermined period of time is in a range of 0.1 ms to 0.5 ms.

2. The power supply of claim 1 , wherein said ignition operation is selected from igniter modes of operation for said high frequency, high voltage pulses which comprise,
said pulses are not needed,
said pulses are needed only for an initial ignition of said arc,
said pulses are needed only for a re-ignition of said arc, and
said pulses are needed for both said initial ignition and said re-ignition of said arc,
wherein said controller is configured to select any of said igniter modes of operation.

3. The power supply of claim 1 , wherein said controller is configured to determine that said condition of said arc is off based on said current passing through said gap, and
wherein said predetermined value is less than 3 amps.

4. The power supply of claim 1 , wherein said controller is configured to determine that said condition of said arc is off based on said voltage across said gap, and
wherein said predetermined value is in a range of 40% to 100% of an open circuit voltage of said power supply.

5. A power supply with synchronized high frequency arc assist, said power supply comprising:
an output circuit that is configured to output at least one of a voltage waveform and a current waveform to a torch;
an ignition circuit that is connected to the torch between the output circuit and the torch and that is configured to initiate high frequency, high voltage pulses across a gap, wherein said high frequency, high voltage pulses are superimposed on said at least one of a voltage waveform and a current waveform;
a monitoring circuit that is configured to monitor at least one of a voltage across said gap and a current passing through said gap;
a control unit comprising a state based programmable controller, said state based controller comprising at least one state based program defining a welding operation based on at least one of a welding waveform type, an arc starting method, a diameter of a consumable, and weld material type;
wherein a desired program is selected from said at least one state based program and said control unit is operatively connected to said output circuit to regulate said at least one of a voltage waveform and a current waveform based on said desired program,
wherein said control unit is configured to select an ignition operation for said high frequency, high voltage pulses based on said desired program,
wherein said control unit is operatively connected to said monitoring circuit and is configured to determine a condition of an arc across said gap based on said at least one of said voltage across said gap and said current passing through said gap,
wherein said control unit is configured to control said ignition circuit based on said selected ignition operation and said arc condition,
wherein the output circuit includes both a center-tapped output choke and a superposition circuit for re-igniting the arc, and the ignition circuit is connected between a center tap of the output choke and the torch,
wherein said control unit is configured to activate said high frequency, high voltage pulses after determining that said condition of said arc is off based on said at least one of said voltage across said gap and said current passing through said gap being at a respective predetermined value for a predetermined period of time, and
wherein said predetermined period of time is in a range of 0.1 ms to 0.5 ms.

6. The power supply of claim 5 , wherein said control unit further comprises a programmable state based schedule for each of at least one state based program, each said programmable state based schedule comprising information on when said arc should be on and when said arc should be off, and information on when said high frequency, high voltage pulses are needed.

7. The power supply of claim 5 , wherein said ignition operation is selected from igniter modes of operation for said high frequency, high voltage pulses which comprise,
said pulses are not needed,
said pulses are needed only for an initial ignition of said arc,
said pulses are needed only for a re-ignition of said arc, and
said pulses are needed for both said initial ignition and said re-ignition of said arc,
wherein said control unit is configured to select any of said igniter modes of operation.

8. The power supply of claim 5 , wherein said control unit is configured to determine that said condition of said arc is off based on said current passing through said gap, and
wherein said predetermined value is less than 3 amps.

9. The power supply of claim 5 , wherein said control unit is configured to determine that said condition of said arc is off based on said voltage across said gap, and
wherein said predetermined value is in a range of 40% to 100% of an open circuit voltage of said power supply.

10. A system for providing high frequency arc assist, said system comprising:
an electrode;
a workpiece; and
a power supply, said power supply comprising,
an output circuit that is configured to output at least one of a voltage waveform and a current waveform to at least one of said electrode and said workpiece;
an ignition circuit that is connected to the electrode through an ignition transformer between the output circuit and the electrode, and that is configured to initiate high frequency, high voltage pulses across a gap between said electrode and said workpiece to create an arc, wherein said high frequency, high voltage pulses are superimposed on said at least one of a voltage waveform and a current waveform;
a monitoring circuit that is configured to monitor at least one of a voltage reading and a current reading across said gap; and
a controller operatively connected to said output circuit to regulate said at least one of said voltage waveform and said

Assignees

• Lincoln Global Inc

Inventors

• Peters Steven R

Classifications

• B23K9/0673 Primary

  Ionisation of the arc gap by means of pulsed or high-frequency voltages · CPC title

• B23K9/0738

  Stabilising of the arc by automatic re-ignition means · CPC title