Systems and methods to provide welding-type arc starting and stabilization with reduced open circuit voltage

Patent metadata

Field	Value
Publication number	US-11958141-B2
Application number	US-201916670993-A
Country	US
Kind code	B2
Filing date	Oct 31, 2019
Priority date	Oct 31, 2019
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

Systems and methods to provide welding-type arc starting and stabilization with reduced open circuit voltage are disclosed. An example welding-type power supply includes: power conversion circuitry configured to convert input power to welding-type power; and control circuitry configured to: control the power conversion circuitry to output a voltage pulse at a first voltage; determine whether the power conversion circuitry outputs current during the voltage pulse; in response to determining that there is less than a threshold output current during the voltage pulse, control the power conversion circuitry to turn off an output or output a second voltage that is less than the first voltage; and in response to determining that the power conversion circuitry outputs at least the threshold output current during the voltage pulse, control the power conversion circuitry to output the welding-type power.

First claim

What is claimed is:

1. A welding-type power supply, comprising:
power conversion circuitry configured to convert input power to welding-type power output; and
control circuitry configured to:
while a welding arc is not present, control the power conversion circuitry to output a voltage pulse at a first voltage;
while the welding arc is not present, determine whether the power conversion circuitry outputs an output current during the voltage pulse;
in response to the welding arc not being present and the output current being less than a threshold output current during the voltage pulse, control the power conversion circuitry to turn off the welding-type power output or output a second voltage that is less than the first voltage; and
in response to determining that the power conversion circuitry outputs at least the threshold output current during the voltage pulse, control the power conversion circuitry to begin outputting the welding-type power output.

2. The welding-type power supply as defined in claim 1 , wherein the control circuitry is configured to control the power conversion circuitry to repeat the voltage pulse at intervals until at least the threshold output current is detected during the voltage pulse.

3. The welding-type power supply as defined in claim 1 , wherein the control circuitry is configured to control the power conversion circuitry to output the welding-type power output in a hot-start phase having a current higher than a setpoint current.

4. The welding-type power supply as defined in claim 1 , wherein the control circuitry is configured to:
during output of the welding-type power output by the power conversion circuitry, monitor the output current; and
in response to determining that the output current is less than a threshold current for at least a threshold time duration, control the power conversion circuitry to decrease an output voltage and control the power conversion circuitry to output the voltage pulse at intervals.

5. The welding-type power supply as defined in claim 1 , further comprising a voltage sensor configured to measure an output voltage of the welding-type power output, wherein the control circuitry is configured to:
during output of the welding-type power output by the power conversion circuitry, monitor the output voltage; and
in response to determining that the output voltage is at least a threshold voltage for at least a threshold time duration, control the power conversion circuitry to decrease the output voltage and control the power conversion circuitry to output the voltage pulse at intervals.

6. The welding-type power supply as defined in claim 1 , wherein the voltage pulse is less than 50 microseconds in duration.

7. The welding-type power supply as defined in claim 6 , wherein the voltage pulse is less than 20 microseconds in duration.

8. The welding-type power supply as defined in claim 1 , wherein the second voltage is selected such that an average open circuit voltage is less than 12 volts.

9. The welding-type power supply as defined in claim 1 , wherein the control circuitry is configured to control the power conversion circuitry to output the second voltage to reduce an average open circuit voltage while arc welding is not occurring.

10. The welding-type power supply as defined in claim 1 , wherein the welding-type power output comprises the first voltage.

11. The welding-type power supply as defined in claim 1 , wherein the control circuitry is configured to:
during output of the welding-type power output by the power conversion circuitry, monitor the output current of the welding-type power output via a current sensor; and
in response to detecting that the output current is less than a threshold current, output a predetermined sequence of duty cycles to one or more switching elements of the power conversion circuitry to cause the power conversion circuitry to output voltage pulses to increase the output current during the voltage pulses.

12. The welding-type power supply as defined in claim 1 , wherein the power conversion circuitry comprises pulse circuitry and welding-type power circuitry, the control circuitry configured to:
control the pulse circuitry to output the voltage pulse at the first voltage and, in response to determining that there is no output current during the voltage pulse, control the power conversion circuitry to output the second voltage; and
control the welding-type power circuitry to output the welding-type power output in response to determining that the pulse circuitry outputs current during the voltage pulse.

13. The welding-type power supply as defined in claim 1 , further comprising a current sensor configured to measure the output current from the power conversion circuitry, the control circuitry configured to determine that there is less than the threshold output current based on a measured output current.

14. The welding-type power supply as defined in claim 1 , further comprising a voltage sensor configured to measure an output voltage from the power conversion circuitry, the control circuitry configured to determine that there is less than the threshold output current based on the measured output voltage.

Assignees

• Illinois Tool Works

Inventors

• Vogel Bernard J
• Madsen Michael D

Classifications

• B23K9/067 Primary

  Starting the arc · CPC title

• B23K9/0731

  Stabilising of the arc tension · CPC title

• B23K9/0732

  Stabilising of the arc current · CPC title

• B23K9/0734

  Stabilising of the arc power · CPC title

• B23K9/0735

  Stabilising of the arc length · CPC title