Prosecution Insights
Last updated: April 19, 2026
Application No. 18/194,838

CONTROLLING ON-TIME OF PWM APPLIED TO POWER BLOCKS IN WELDING SYSTEM

Non-Final OA §102§103
Filed
Apr 03, 2023
Examiner
CLARK, RYAN C
Art Unit
3745
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
The ESAB Group, Inc.
OA Round
1 (Non-Final)
87%
Grant Probability
Favorable
1-2
OA Rounds
1y 12m
To Grant
96%
With Interview

Examiner Intelligence

Grants 87% — above average
87%
Career Allow Rate
231 granted / 265 resolved
+17.2% vs TC avg
Moderate +8% lift
Without
With
+8.5%
Interview Lift
resolved cases with interview
Fast prosecutor
1y 12m
Avg Prosecution
37 currently pending
Career history
302
Total Applications
across all art units

Statute-Specific Performance

§101
2.6%
-37.4% vs TC avg
§103
38.8%
-1.2% vs TC avg
§102
30.5%
-9.5% vs TC avg
§112
26.4%
-13.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 265 resolved cases

Office Action

§102 §103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Objections Claim 7 is objected to because of the following informalities: Line 2 recites, “adjusting include adjusting the on-time” should likely read, “adjusting includes adjusting the on-time”. Appropriate correction is required. Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claims 1-4, 6-14, and 16-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Forslund (US PGPUB 2018/0056427 A1). PNG media_image1.png 438 794 media_image1.png Greyscale Regarding claim 1, Forslund discloses a method of controlling (Fig. 3) pulse width modulation (PWM) (308) applied to at least one power inverter (“output inverter” [0029]) to generate a weld current ([0031], “output current or voltage values”) for cutting or welding (318), comprising: receiving current values indicative of the weld current during a cycle of the PWM (301 “actual U or I”); receiving a target current value (310, reference value, [0035]) indicative of a target current for the weld current ([0035]); during the cycle, turning ON a pulse to energize the at least one power inverter; and after turning ON the pulse, repeating multiple times during the cycle ([0028], “The control module 306 can generate control signals for adjusting operation of the PWM and synchronizer module 308. Specifically, the control module 306 can adjust operation of the PWM and synchronizer module 308 to control the output current or voltage of the welding system 300. In various embodiments, there may be a peak-current-control circuit positioned between the control module 306 and the PWM and synchronizer module 308 (not shown for simplicity in FIG. 3).”): determining whether to adjust an on-time of the pulse based on the current values and the target current value in order to drive the weld current toward the target current ([0028]); and adjusting the on-time responsive to determining ([0028], the control module adjusts the operation of the PWM to control the output current or voltage of the welding system). Regarding claim 2, Forslund discloses all of claim 1 as above, wherein: repeating the multiple times includes repeating the multiple time at a time interval that is less than a period of the cycle ([0028], implied with the use and control of PWM, claim 17). Regarding claim 3, Forslund discloses all of claim 1 as above, wherein: determining includes determining whether to increase or decrease the on-time; and adjusting includes: when it is determined to increase the on-time, increasing the on-time by not turning OFF the pulse ([0028], implied with the use and control of PWM, claim 10); and when it is determined to decrease the on-time, decreasing the on-time by turning OFF the pulse ([0028], implied with the use and control of PWM, claim 10). Regarding claim 4, Forslund discloses all of claim 1 as above, further comprising: for each successive cycles of the PWM, repeating (i) turning ON the pulse, and (ii) repeating the multiple times in order to drive the weld current to the target current (see the feedback loop 318 -> 312 -> 310 -> 306). Regarding claim 6, Forslund discloses all of claim 1 as above, wherein: turning ON the pulse includes turning ON the pulse at a start of the cycle (Fig. 2, Gate A / 202, Y-axis and T). Regarding claim 7, Forslund discloses all of claim 1 as above, wherein: adjusting include adjusting the on-time until adjusting the on-time includes turning OFF the pulse responsive to determining to decrease the on-time ([0028], implied with the use and control of PWM, claim 10). Regarding claim 8, Forslund discloses all of claim 1 as above, wherein determining includes: computing a set value (310) indicative of whether to increase or decrease the on-time based on the current values and the target current value ([0028], implied with the use and control of PWM, claim 10). Regarding claim 9, Forslund discloses all of claim 8 as above, wherein adjusting includes: when the representative signal does not exceed the set value, increasing the on-time by not turning OFF the pulse ([0028], implied with the use and control of PWM, claim 10); and when the representative signal exceeds the set value, decreasing the on-time by turning OFF the pulse ([0028, implied with the use and control of PWM, claim 10). Regarding claim 10, Forslund discloses all of claim 1 as above, wherein the at least one power inverter includes multiple power inverters (Fig. 3, demonstrated by two signals going to two half bridge output inverters [0029]) configured to generate multiple currents responsive to the PWM (Fig. 3), and the method further comprises: summing the multiple currents to produce the weld current (the Examiner notes that with the two half-gate inverters the power goes to the same load and therefore must be summed by Kirchhoff’s Current Law, “The algebraic sum of all currents entering and exiting a node must equal zero”); and providing the PWM to each of the multiple power inventers (Gate A, Gate B). Regarding 11, Forslund discloses an apparatus (Fig. 3) comprising: at least one power inverter (“output inverter” [0029]) of a welding system (Fig. 3, 318); and a controller (300) configured to perform controlling pulse width modulation (PWM) applied to the at least one power inverter to generate a weld current ([0031], “output current or voltage values”) for cutting or welding (318) by: receiving current values indicative of the weld current during a cycle of the PWM (301 “actual U or I”); receiving a target current value (310, reference value, [0035]) indicative of a target current for the weld current ([0035]); during the cycle, turning ON a pulse to energize the at least one power inverter; and after turning ON the pulse, repeating multiple times during the cycle ([0028], “The control module 306 can generate control signals for adjusting operation of the PWM and synchronizer module 308. Specifically, the control module 306 can adjust operation of the PWM and synchronizer module 308 to control the output current or voltage of the welding system 300. In various embodiments, there may be a peak-current-control circuit positioned between the control module 306 and the PWM and synchronizer module 308 (not shown for simplicity in FIG. 3).”): determining whether to adjust an on-time of the pulse based on the current values and the target current value in order to drive the weld current toward the target current ([0028]); and adjusting the on-time responsive to determining ([0028], the control module adjusts the operation of the PWM to control the output current or voltage of the welding system). Regarding claim 12, Forslund discloses all of claim 11 as above, wherein the controller is further configured to perform: repeating the multiple times includes repeating the multiple time at a time interval that is less than a period of the cycle ([0028], implied with the use and control of PWM, claim 19). Regarding claim 13, Forslund discloses all of claim 11 as above, wherein: the controller is configured to perform determining by determining wherein to increase or decrease the on-time; and the controller is configured to perform adjusting by: when it is determined to increase the on-time, increasing the on-time by not turning OFF the pulse ([0028], implied with the use and control of PWM, claim 10); and when it is determined to decrease the on-time, decreasing the on-time by turning OFF the pulse ([0028], implied with the use and control of PWM, claim 10). Regarding claim 14, Forslund discloses all of claim 11 as above, wherein the controller is further configured to perform: for each successive cycles of the PWM, repeating (i) turning ON the pulse, and (ii) repeating the multiple times in order to drive the weld current to the target current (see the feedback loop 318 -> 312 -> 310 -> 306). Regarding claim 16, Forslund discloses all of claim 11 as above, wherein: the controller is configured to perform turning ON the pulse includes turning ON the pulse at a start of the cycle (Fig. 2, Gate A / 202, Y-axis and T). Regarding claim 17, Forslund discloses all of claim 11 as above, wherein: the controller is configured to perform adjusting by adjusting the on-time until adjusting the on-time includes turning OFF the pulse responsive to determining to decrease the on-time ([0028], implied with the use and control of PWM, claim 10). Regarding claim 18, Forslund discloses all of claim 11 as above, wherein the controller is configured to perform determining by: computing a set value (310) indicative of whether to increase or decrease the on-time based on the current values and the target current value ([0028], implied with the use and control of PWM, claim 10); and comparing the set value to a representative signal indicative of the weld current (312), wherein the controller is configured to perform adjusting based on result of comparing (claim 10). Regarding claim 19, Forslund discloses all of claim 18 as above, wherein the controller is configured to perform adjusting by: when the representative signal does not exceed the set value, increasing the on-time by not turning OFF the pulse ([0028], implied with the use and control of PWM, claim 10); and when the representative signal exceeds the set value, decreasing the on-time by turning OFF the pulse ([0028, implied with the use and control of PWM, claim 10). Regarding claim 20, Forslund discloses all of claim 11 as above, wherein the at least one power inverter includes multiple power inverters (Fig. 3, demonstrated by two signals going to two half bridge output inverters [0029]) configured to generate multiple currents responsive to the PWM (Fig. 3), and the method further comprises: a summing to sum the multiple currents to produce the weld current (the Examiner notes that with the two half-gate inverters the power goes to the same load and therefore must be summed by Kirchhoff’s Current Law, “The algebraic sum of all currents entering and exiting a node must equal zero”); and the controller is configured to perform providing the PWM to each of the multiple power inventers (Gate A, Gate B). Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claims 5 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Forslund (US PGPUB 2018/0056427 A1) in view of Nelson (US PGPUB 2019/0372451 A1). Regarding claim 5, Forslund discloses all of claim 1 as above. However, Forslund does not disclose, “processing the target current value and the current values using a proportional-integral-derivative (PID) algorithm.” Nelson teaches in the field of control circuits of welding-type power supplies, a PID controller for controlling welding-type output power ([0055]). It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the method of Forslund to use a PID controller or PID circuit as taught by Nelson, as both references are in the same field of endeavor, and one of ordinary skill would appreciate that, “The command signal output by the first control circuit 400 to the PID circuit 302 may be representative of the desired welding-type output power, one or more desired characteristics of the output power, appropriate changes to the output power that would bring it into line with the desired output power, and/or appropriate changes to the first and/or second control signals that would produce the desired welding-type output power with any desired characteristics. [0055]” Regarding claim 15, Forslund discloses all of claim 11 as above. However, Forslund does not disclose, “the controller is configured to perform processing the target current value and the current values using a proportional-integral-derivative (PID) algorithm.” Nelson teaches in the field of control circuits of welding-type power supplies, a PID controller for controlling welding-type output power ([0055]). It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the apparatus of Forslund to use a PID controller or PID circuit as taught by Nelson, as both references are in the same field of endeavor, and one of ordinary skill would appreciate that, “The command signal output by the first control circuit 400 to the PID circuit 302 may be representative of the desired welding-type output power, one or more desired characteristics of the output power, appropriate changes to the output power that would bring it into line with the desired output power, and/or appropriate changes to the first and/or second control signals that would produce the desired welding-type output power with any desired characteristics. [0055]” Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. PNG media_image2.png 468 602 media_image2.png Greyscale US PGPUB 2019/0381597 A1 discloses a welding power supply. PNG media_image3.png 332 484 media_image3.png Greyscale US PGPUB 2014/0376268 A1 discloses a metal working power supply converter system and method with PWM controls. PNG media_image4.png 578 670 media_image4.png Greyscale US PGPUB 2021/0039186 A1 discloses a method and apparatus for providing welding type power using double forward converter, including PWM on two different inverters. PNG media_image5.png 391 514 media_image5.png Greyscale US PGPUB 2019/0190403 A1 discloses a system-connected inverter device and method for operating same. Any inquiry concerning this communication or earlier communications from the examiner should be directed to RYAN C CLARK whose telephone number is (571)272-2871. The examiner can normally be reached Monday - Thursday 0730-1730, Alternate Fridays 0730-1630. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Courtney D Heinle can be reached at (571)-270-3508. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /RYAN C CLARK/Examiner, Art Unit 3745
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Prosecution Timeline

Apr 03, 2023
Application Filed
Feb 06, 2026
Non-Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
87%
Grant Probability
96%
With Interview (+8.5%)
1y 12m
Median Time to Grant
Low
PTA Risk
Based on 265 resolved cases by this examiner. Grant probability derived from career allow rate.

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