Prosecution Insights
Last updated: April 19, 2026
Application No. 18/556,242

METHOD OF CONTROLLING A POWER CONVERTER, CONVERTER ARRANGEMENT AND COMPUTER PROGRAM PRODUCT

Final Rejection §103
Filed
Oct 19, 2023
Examiner
NOVAK, PETER MICHAEL
Art Unit
2838
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Hitachi Energy Ltd.
OA Round
2 (Final)
88%
Grant Probability
Favorable
3-4
OA Rounds
2y 3m
To Grant
97%
With Interview

Examiner Intelligence

Grants 88% — above average
88%
Career Allow Rate
592 granted / 672 resolved
+20.1% vs TC avg
Moderate +9% lift
Without
With
+8.6%
Interview Lift
resolved cases with interview
Typical timeline
2y 3m
Avg Prosecution
37 currently pending
Career history
709
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
51.7%
+11.7% vs TC avg
§102
20.7%
-19.3% vs TC avg
§112
20.2%
-19.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 672 resolved cases

Office Action

§103
DETAILED ACTION The instant action is in response to application 19 October 2023. 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 . Specification The specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant's cooperation is requested in correcting any errors of which applicant may become aware in the specification. Priority Acknowledgment is made of applicant's claim for priority based on a WIPO application filed in Italy on 20 April 2021. Response to Arguments The specification objections have been withdrawn. The drawing objection has been withdrawn. Applicant’s responses to the merirts have been considered but are moot for not considering the present references. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. For method claims, note that under MPEP 2112.02, the principles of inherency, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device will inherently perform the claimed process. In re King, 801 F.2d 1324, 231 USPQ 136 (Fed. Cir. 1986). Therefore the previous rejections based on the apparatus will not be repeated. (The claims have been condensed.) 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. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. 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 of this title, 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 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over Shuai et als “Transient Angle Stability of Virtual Synchronous Generators Using Lyapunov’s Direct Method” (IEEE NPL) in view of Taul’s et als “Current Limiting Control With Enhanced Dynamics of Grid-Forming Converters During Fault Conditions” (IEEE NPL) and Garcia (US 20150137520). As to claim 1, Shuai discloses a method of controlling a power converter (Fig. 1/2), wherein the method comprises:]determining a frequency control error (input kp) in dependence on at least a setpoint frequency (w0) and an actual frequency (w), determining an active power target (P*), determining a phase angle target (theta (output 1/s)),determining a voltage control error (input Dq) in dependence on at least a setpoint voltage (E0) and an actual voltage (E), determining a reactive power target (Q*), [[- ]]determining an output voltage target (Vd*), and controlling the power converter based on the output voltage target (Fig. 1, has phase and PWM inputs) and the phase angle target, wherein the method comprises at least one of Shuai does not disclose freezing the active power target (PSet) to remain constant in case a fault signal (SF) indicating a fault is detected, freezing the phase angle target (Ф) to remain constant in case a fault signal (SF) indicating a fault is detected, freezing the reactive power target (Exc) to remain constant in case a fault signal (SF) indicating a fault is detected, or freezing the output voltage target (Vd*) to remain constant in case a fault signal (SF). Garcia teaches freezing the active power target (PSet) to remain constant in case a fault signal (SF) indicating a fault is detected, freezing the phase angle target (Ф) to remain constant in case a fault signal (SF) indicating a fault is detected, freezing the reactive power target (Exc) to remain constant in case a fault signal (SF) indicating a fault is detected are frozen to the saved/pre-fault values, the WTGs are working in their local LVRT mode during the FREEZE-Q CTRL state.”), or freezing the output voltage target (Vd*) to remain constant in case a fault signal (SF) (See Fig. 5, specifying a freeze control state, and ¶8 “and at least that part of the central plant controller which provides control of electric production in the nominal-operation mode is frozen and a pre-fault-operation value of at least one control variable is stored.” describing how at least one individual control value shown in Fig. 4 corresponding to Pref (power), PFref (phase angle), Qref (reactive power), and Vref (votlage)). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device above to use the fault control of Garcia in the system above to provide low voltage ride through. As to claim 2, Shuai in view of Garcia teaches wherein the method comprises determining [[a]]an initialization value of at least one of an actual active power (Pact) and an actual reactive power (Qact) of the power converter when the fault signal (SF) indicating a fault is detected (The value is frozen, so it must be stored from prefault data). As to claim 3, Shuai in view of Garcia teaches wherein the method comprises continuously storing data in a memory in predetermined periods, wherein the data include at least one of the actual active power and the actual reactive power, and wherein determining the initialization value includes selecting the initialization value out of the data stored in the memory (The value is frozen, so it must be stored from prefault data).. As to claim 4, Shuai in view of Garcia teaches wherein the method comprises determining that the fault is no longer detected, and determining the active power target using the initialization value of the actual active power (Shuai, Fig. 2a) and/or determining the reactive power target using the initialization value of the actual reactive power (Shuai, Fig. 2b). As to claim 5, Shuai in view of Garcai teaches wherein the method comprises waiting for a predetermined time after detecting that the fault is no longer (Garcia, Fig. 5) detected before determining the active power target (PSet) using the initialization value of the actual active power (Shuai, Fig. 2) and/or determining the reactive power target using the initialization value of the actual reactive power (Shuai, Fig. 2). As to claim 6, Shuai in view of Garcia teaches wherein the method is configured to mimic a synchronous generator (title Shuai). As to claim 7, Shuai in view of Garcia teaches wherein, in case no fault signal indicating a fault is detected, determining the phase angle target in dependence on at least the active power target includes: determining an active power error in dependence on at least the active power target and an actual active power, and determining the phase angle target in dependence on at least the active power error (Shuai, Fig. 2). As to claim 9, wherein, Shuai in view of Garcia teaches in case no fault signal (SF) indicating a fault is detected, determining the output voltage target in dependence on at least the reactive power target (Exc) includes: determining a reactive power error in dependence on at least the reactive power target and an actual reactive power and determining the output voltage target in dependence on at least the reactive power error (Shuai, Fig. 2). As to claim 11, Shuai in view of Garcia teaches a control arrangement and -a power converter (Virtual synchronous generator) that is realized as a voltage-controlled voltage source converter, wherein the control arrangement (item generating gate signals) is configured to execute the method of controlling the power converter of claim 1. As to claim 12, Shuai in view of Garcia teaches a non-transitory computer-readable medium having a computer program comprising instructions stored thereon, wherein the instructions, when executed by a processor, cause the processor to perform the method of controlling the power converter of claim 1 (Garcia, ¶109). As to claims 13-20, these are similar to claims already rejected above and are obvious for similar reasons. Conclusion Examiner has cited particular column, paragraph, and line numbers in the references applied to the claims above for the convenience of the applicant. Although the specified citations are representative of the teachings of the art and are applied to specific limitations within the individual claim, other passages and figures may apply as well. It is respectfully requested from the applicant in preparing responses, to fully consider the references in their entirety as potentially teaching all or part of the claimed invention, as well as the context of the passage as taught by the prior art or disclosed by the Examiner. In the case of amending the claimed invention, Applicant is respectfully requested to indicate the portion(s) of the specification which dictate(s) the structure relied on for proper interpretation and also to verify and ascertain the metes and bounds of the claimed invention. Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER M NOVAK whose telephone number is (571)270-1375. The examiner can normally be reached on 9AM-5PM,Monday through Thursday, EST. 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, Crystal Hammond can be reached on 571-270-1682. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see https://ppair-my.uspto.gov/pair/PrivatePair. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /PETER M NOVAK/ Primary Examiner, Art Unit 2839
Read full office action

Prosecution Timeline

Oct 19, 2023
Application Filed
Oct 19, 2025
Non-Final Rejection — §103
Feb 13, 2026
Response Filed
Mar 08, 2026
Final Rejection — §103 (current)

Precedent Cases

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

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Prosecution Projections

3-4
Expected OA Rounds
88%
Grant Probability
97%
With Interview (+8.6%)
2y 3m
Median Time to Grant
Moderate
PTA Risk
Based on 672 resolved cases by this examiner. Grant probability derived from career allow rate.

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