Welding wire feeder bus control system and method

Patent metadata

Field	Value
Publication number	US-10384289-B2
Application number	US-201314102209-A
Country	US
Kind code	B2
Filing date	Dec 10, 2013
Priority date	Jun 8, 2012
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

A welding wire feeder includes a wire feed drive and wire feed control circuitry coupled to the wire feed drive to control the drive of welding wire towards the welding application. The welding wire feeder includes power conversion circuitry configured to receive input power and to convert the input power to welding output suitable for a welding application, output voltage sensors configured to measure output voltage, output current sensors configured to measure output current, and control circuitry coupled to the power conversion circuitry and to the output voltage and current sensors. The power conversion circuitry includes power storage circuitry configured to store energy and to discharge at least a portion of the stored energy during an overdraw event. The control circuitry is configured to control the output current during the overdraw event to maintain a stored energy value of the power storage circuitry greater than a desired minimum energy value.

First claim

The invention claimed is:

1. A welding wire feeder comprising:
a welding wire feed drive configured to drive welding wire towards a welding application;
wire feed control circuitry coupled to the welding wire feed drive and configured to control the drive of welding wire towards the welding application;
power conversion circuitry configured to receive input power and to convert the input power to welding output suitable for the welding application, wherein the power conversion circuitry comprises:
an internal bus arranged between a boost converter and a buck converter;
at least one bus capacitor arranged on the internal bus and configured to store energy and to discharge at least a portion of the stored energy during an overdraw event; and
one or more bus sensors to sense a bus current through the at least one bus capacitor or a bus voltage at the internal bus across the at least one bus capacitor; and
direct current (DC) switched-mode converter circuitry having at least one switch, wherein the DC switched-mode converter circuitry is electrically coupled between the at least one bus capacitor and input circuitry that receives the input power;

an output voltage sensor configured to measure output voltage of the welding;
an output current sensor configured to measure output current of the welding output; and
control circuitry coupled to the power conversion circuitry, to the output voltage sensor, and to the output current sensor, wherein the control circuitry is configured to control an input current command of the at least one switch of the DC switched-mode converter circuitry based at least in part on the one or more bus sensors, the output voltage, the output current, or both, to control an input current to the power conversion circuitry during the overdraw event to maintain a stored energy value of the at least one bus capacitor greater than a desired minimum energy value of the at least one bus capacitor, wherein the desired minimum energy value is greater than zero.

2. The welding wire feeder of claim 1 , wherein
the DC switched-mode converter circuitry includes the boost converter coupled to the internal bus and is configured to convert input power into bus power of the internal bus.

3. The welding wire feeder of claim 1 , wherein the overdraw event comprises a short circuit clearing event.

4. The welding wire feeder of claim 1 , wherein a duration of the overdraw event is less than approximately 0.3 seconds.

5. The welding wire feeder of claim 1 , wherein the control circuitry is configured to compare a net flow of energy relative to the at least one bus capacitor to one or more thresholds, wherein the one or more thresholds comprises a threshold based at least in part on design limits of the power conversion circuitry.

6. The welding wire feeder of claim 1 , wherein the control circuitry is configured to compare a net flow of energy relative to the at least one bus capacitor to one or more thresholds, wherein the one or more thresholds comprises a threshold based at least in part on the energy stored on the at least one bus capacitor, a value of the output current, a current ramp rate, a voltage ramp rate, or any combination thereof.

7. The welding wire feeder of claim 1 , wherein the overdraw event comprises a period of time when power of the welding output is greater than power received by the at least one bus capacitor.

8. The welding wire feeder of claim 1 , wherein the control circuitry is configured to determine a net flow of energy based on welding output over a sample interval.

9. The welding wire feeder of claim 1 , wherein the control circuitry is configured to reduce the welding output current to maintain both the arc and the bus capacitor above the desired minimum energy value during the overdraw event.

10. The welding wire feeder of claim 1 , wherein the control circuitry is configured to initiate a signal to the welding power source to increase the input current based upon a comparison between the input power voltage and the voltage across the internal bus.

11. A method of operating a welding wire feeder, comprising:
receiving an input power signal from a power source;
converting the input power signal to a bus power signal on an internal bus via direct current (DC) switched-mode converter circuitry having at least one switch, wherein the internal bus comprises at least one bus capacitor;
storing energy with the at least one bus capacitor with at least a portion of the bus power signal;
detecting at least one of a stored energy value of the at least one bus capacitor or a bus voltage of the at least one bus capacitor via one or more bus sensors located at an internal bus arranged between a boost converter and a buck converter;
converting the bus power signal to a welding output signal, wherein the welding output signal is suitable for a controlled waveform welding process;
detecting an output energy flow of the welding output signal;
converting at least a portion of the stored energy of the at least one bus capacitor to contribute to the welding output signal during an overdraw event, wherein the welding output signal during the overdraw event is greater than the input power signal during the overdraw event; and
controlling an input current command of the at least one switch of the DC switched-mode converter circuitry based at least in part on the stored energy value of the at least one bus capacitor or the bus voltage of the at least one bus capacitor, an output voltage, an output current, or both, to control input current to control the conversion of the stored energy of the at least one bus capacitor to maintain the stored energy value greater than a desired minimum energy value of the at least one bus capacitor, wherein the desired minimum energy value is greater than zero.

12. The method of claim 11 , wherein the overdraw event comprises a short circuit clearing event, and a duration of the short circuit clearing event is less than 0.3 seconds.

13. The method of claim 11 , wherein controlling the conversion of the stored energy of the at least one bus capacitor comprises:
determining a sustainability current value based at least in part on the stored energy value of the at least one bus capacitor, the output energy flow, and a predicted duration of the overdraw event; and
reducing a current component of the welding output signal to the sustainability current value.

14. The method of claim 13 , wherein the predicted duration of the overdraw event is based at least in part on a pulse waveform of the controlled waveform welding process, a usage pattern, historical data, or any combination thereof.

15. The method of claim 11 , comprising:
comparing a net flow of energy to one or more thresholds, wherein the one or more thresholds is based at least in part on the stored energy value of the at least one bus capacitor, a current component of the welding output signal, a current ramp rate of the current component of the welding output signal, a voltage ramp rate of the welding output signal, or any combination thereof; and
controlling the current component of the welding output signal based at least in part on the comparison of the net flow of energy to the one or more thresholds.

16. The method of claim 11 , wherein controlling the conversion of the stored energy of the at least one bus capacitor comprises reducing a current component of the welding output signal to a predefined current value.

17. A system comprising:
power conversion circuitry configured to receive input power and to convert the input power to an output power waveform

Assignees

• Illinois Tool Works

Inventors

• Beistle Edward G

Classifications

• B23K9/125

  Feeding of electrodes (for stabilising arc B23K9/073) · CPC title

• B23K9/124

  Circuits or methods for feeding welding wire · CPC title

• B23K9/1043 Primary

  characterised by the electric circuit (B23K9/1012 takes precedence) · CPC title

• B23K9/1012 Primary

  characterised by parts of the process · CPC title