Method and apparatus for characterizing a welding output circuit path

• US 7,683,290 B2
• Filed: 12/05/2006
• Issued: 03/23/2010
• Est. Priority Date: 05/12/2006
• Status: Active Grant

• Current Assignee: Lincoln Global Incorporated (Lincoln Electric Holdings Incorporated)
• Original Assignee: Lincoln Global Incorporated (Lincoln Electric Holdings Incorporated)
• Inventors: Daniel, Joe, Matthews, Tom
• Primary Examiner(s): Ralis; Stephen J
• Application Number:
  US11/566,719
• Publication Number:
  US 20070262064A1
• Time in Patent Office: 1,204 Days
• Field of Search: 219/130.01, 219/130.21, 219/130.33, 219/130.51
• US Class Current: 219/130.01
• CPC Class Codes: B23K 9/0953 using computing means
• CPC Class Codes: B23K 9/0956 using sensing means, e.g. optical
• CPC Class Codes: B23K 9/1043 characterised by the electric circuit B23K9/1012 takes precedence
• CPC Class Codes: B23K 9/1056 by using digital means B23K9/1068 takes precedence

Abstract

Methods and apparatus to characterize a welding output circuit path. A welding output circuit path is characterized in real time with respect to a true energy and/or true power input to the welding output circuit path. A welding output circuit path is also characterized with respect to an inductance of the welding output circuit path. A welding output circuit path is further characterized with respect to a welding output waveform.

Claims

1. An apparatus to characterize a welding output circuit path with respect to an inductance of said welding output circuit path, said apparatus comprising a welding power source capable of:

(a) regulating a welding output current applied to a welding output circuit path to a regulated output current value, or regulating a welding output voltage applied to said welding output circuit path to a regulated output voltage value;

(b) measuring a value of a resultant welding output voltage at said regulated output current value, or measuring a value of a resultant welding output current at said regulated output voltage value;

(c) calculating a resistance value of said welding output circuit path in response to said regulated output current value and said measured output voltage value, or in response to said regulated output voltage value and said measured output current value;

(d) initiating a decaying of said welding output current from said regulated output current value or from said measured output current value;

(e) sampling said decaying welding output current at a plurality of times from an initial current I_o sampled at an initial time T_o, to a final current I_f sampled at a final time T_f as said welding output current decays, forming a plurality of sample intervals;

(f) calculating a dissipated energy within said welding output circuit path in response to each said sample interval of the welding output current between said initial current I_o and said final current I_f and in response to said resistance value;

(g) calculating a total dissipated energy for said welding output circuit path in response to said calculated dissipated energies for each said sample of welding output current between said initial current I_o and said final current I_f; and

(h) calculating an inductance value of said welding output circuit path in response to said total dissipated energy, said initial current I_o, and said final current I_f.

2. The apparatus of claim 1 wherein said welding output circuit path runs from said welding power source through a welding cable to a welding tool, through a workpiece and/or to a workpiece connector, and back through said welding cable to said welding power source.

3. The apparatus of claim 1 wherein said welding power source is further capable of analyzing at least one of said estimated inductance value and said calculated resistance value with respect to desired output parameters stored within said welding power source and displaying an indication of acceptability of said welding output circuit path.

4. The apparatus of claim 3 wherein said desired output parameters include at least one of a desired output current set point, a desired rate of change of an output current level, and an amount of voltage available from a welding power source.

5. A method to characterize a welding output circuit path with respect to an inductance of said welding output circuit path, said method comprising:

regulating a welding output current applied to a welding output circuit path to a regulated current value, or regulating a welding output voltage applied to said welding output circuit path to a regulated voltage value;

measuring a value of a resultant welding output voltage at said regulated output current value, or measuring a value of a resultant welding output current at said regulated output voltage value;

calculating a resistance value of said welding output circuit path in response to said regulated output current value and said measured output voltage value, or in response to said regulated output voltage value and said measured output current value;

initiating a decaying of said welding output current from said regulated output current value or from said measured output current value;

sampling said decaying welding output current at a plurality of times from an initial current I_o sampled at an initial time T_o, to a final current I_f sampled at a final time T_f as said welding output current decays, forming a plurality of sample intervals;

calculating a dissipated energy within said welding output circuit path in response to each said sample interval of the welding output current between said initial current I_o and said final current I_f and in response to said resistance value;

calculating a total dissipated energy for said welding output circuit path in response to said calculated dissipated energies for each said sample of welding output current between said initial current I_o and said final current I_f; and

calculating an inductance value of said welding output circuit path in response to said total dissipated energy, said initial current I_o, and said final current I_f.

6. The method of claim 5 wherein said welding output circuit path runs from a welding power source through a welding cable to a welding tool, through a workpiece and/or to a workpiece connector, and back through said welding cable to said welding power source.

7. The method of claim 5 further comprising analyzing at least one of said calculated inductance value and said calculated resistance value with respect to predefined and stored output parameters, and displaying an indication of acceptability of welding output circuit path.

8. The method of claim 7 wherein said stored output parameters include at least one of a desired output current set point, a desired rate of change of an output current level, and an amount of voltage available from a welding power source.

9. An apparatus to characterize a welding output circuit path with respect to a welding output waveform, said apparatus comprising:

(a) means for selecting a welding output waveform to be generated, wherein said welding output waveform comprises a welding out parameter component which is a function of at least one of a welding output current component and a welding output voltage component;

(b) means for establishing a welding output circuit path;

(c) means for commanding at least one predefined welding output parameter set point and at least one corresponding predefined welding output parameter ramp rate to said at least one set point, wherein said set point and said ramp rate characterize at least one portion of said selected welding output waveform;

(d) means for attempting to generate said at least one portion of said welding output waveform and applying said at least one portion of said welding output waveform to said welding output circuit path;

(e) means for monitoring said welding output parameter component of said at least one portion of said generated welding output waveform; and

(f) means for determining, in response to said monitoring, whether or not said generated welding output waveform is in a saturated condition.

10. The apparatus of claim 9 further comprising means for calculating a percentage of time that said saturated condition occurs.

11. The apparatus of claim 9 further comprising means for calculating a frequency of occurrence of said saturated condition.

12. The apparatus of claim 10 further comprising means for displaying an indication that said welding output circuit path is:

acceptable with respect to said welding output waveform if said calculated percentage of time is within a predefined range of acceptability; and

unacceptable with respect to said welding output waveform if said calculated percentage of time is outside of said predefined range of acceptability.

13. The apparatus of claim 11 further comprising means for displaying an indication that said welding output circuit path is:

acceptable with respect to said welding output waveform if said calculated frequency of occurrence is within a predefined range of acceptability; and

unacceptable with respect to said welding output waveform if said calculated frequency of occurrence is outside of said predefined range of acceptability.

14. The apparatus of claim 9 further comprising means for generating statistical data characterizing any said saturated condition over at least a period of said welding output waveform.

15. A method to characterize, in real time, a welding output circuit path with respect to at least one of a true energy and a true power input to said welding output circuit path, a method comprising:

establishing a welding output circuit path running from a welding power source through a welding cable to a welding tool, through at least one of a workpiece and to a workpiece connector, and back through said welding cable to said welding power source;

generating a welding output waveform, within said welding power source, which is transmitted through said welding output circuit path, and wherein said welding output waveform comprises a welding output current component and a welding output voltage component;

continuously sampling instantaneous output current levels and instantaneous output voltage levels of said welding output waveform within said welding power source at a predefined sample rate;

continuously generating, within said welding power source, a product of each of said sampled output current levels and said corresponding sampled output voltage levels as part of determining at least one of a true energy output level and a true power output level from said welding power source into said welding output circuit path in real time; and

dividing at least one of said true energy output level and said true power output level over a predefined time interval by a deposited amount of wire during said predefined time interval to calculate at least one of a true energy per unit amount of deposited wire and a true power per unit amount of deposited wire.

16. The method of claim 15 further comprising displaying at least one of said true energy per unit amount deposited wire and said true power per unit amount of deposited wire on a display along with an indication of acceptability of at least one of said true energy per unit amount of deposited wire and said true power per unit amount of deposited wire.