Prosecution Insights
Last updated: April 19, 2026
Application No. 18/688,973

VOLTAGE SOURCE MULTI-LEVEL CONVERTER TOPOLOGY AND CONTROL METHOD THEREOF

Final Rejection §103
Filed
Mar 04, 2024
Examiner
ORTIZ, ELIM
Art Unit
2836
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Shandong University
OA Round
2 (Final)
79%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
99%
With Interview

Examiner Intelligence

Grants 79% — above average
79%
Career Allow Rate
449 granted / 567 resolved
+11.2% vs TC avg
Strong +23% interview lift
Without
With
+22.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
26 currently pending
Career history
593
Total Applications
across all art units

Statute-Specific Performance

§101
1.1%
-38.9% vs TC avg
§103
58.0%
+18.0% vs TC avg
§102
19.2%
-20.8% vs TC avg
§112
14.6%
-25.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 567 resolved cases

Office Action

§103
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 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 1-4 and 7-10 are rejected under 35 U.S.C. 103 as being unpatentable over Ma (CN 110829872A) in view of Lu (US 2019/0238062). Regarding claim 1, The combination teaches a voltage source multi-level converter topology (see Fig. 1 and 2), wherein the voltage source multi-level converter topology comprises two groups of half-bridge circuits (see T1 T ’1 and T 2 T ’2 ), two groups of flying capacitors (see Cf1 and Cf2) and a plurality of switches (see T11, T’11 T12 and T’12), wherein each group of half-bridge circuits comprise two direct-current connection ends, and outputs of the two groups of half-bridge circuits are both connected (see Figs 1 and 2), through a switch (see T 3 and T’3 ) to the two groups of flying capacitors that are in series (see Cf1 and Cf2); and a neutral point (see O1) of a connection between the two groups of flying capacitors is connected to an alternating-current end (see Fig. 1 and Fig. 2) through two switches that are in reverse series (see T12 and T’11), and an overall positive electrode and an overall negative electrode of the two groups of flying capacitors that are in series are respectively connected to the alternating-current end through switches (see Fig. 1 and Fig. 2). However, Ma does not disclose wherein, all the switches are insulate-gate bipolar transistors (IGBTs). Yet, Lu in the field of three-level Neutral Point Clamped (NPC) inverters/rectifiers, for power applications, such as electric vehicle traction inverters teaches all the switches are insulate-gate bipolar transistors (IGBTs) (see para 0005, Fig. 2) Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Ma with the teachings of Lu by having wherein, all the switches are insulate-gate bipolar transistors (IGBTs) in order to provide superior balance of high power handling, efficiency in high-voltage applications, and simplified drive circuitry while offering robustness and thermal performance. Regarding claim 2, The combination teaches the voltage source multi-level converter topology according to claim 1. Yet does not disclose wherein the alternating-current end does not cascade a full-bridge inversion unit. However, implementing a does not cascade a full-bridge inversion unit, would have been obvious because a particular known technique was recognized as part of the ordinary capabilities of one skilled in the art. Further the claim would have been obvious because “a person of ordinary skill has good reason to pursue the known options within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense.” Selecting an a known inverter topology would not include an inventive step nor novelty. Regarding claim 3. The combination teaches wherein the alternating-current end cascades one or more full-bridge inversion units (see 211 and 212, Fig. 1; Ma). Regarding claim 4. The combination teaches the voltage source multi-level converter topology according to claim 3. However, does not disclose wherein when the alternating-current end cascades n full-bridge inversion units, 6*2n+1 levels are generated. Yet, the claim would have been obvious because a person of ordinary skill in the art would have been motivated to combine the prior art to achieve the claimed invention and that there would have been a reasonable expectation of success. Further the formula is known for a 6-level output cascade inverter. Regarding claim 7, The combination teaches wherein the direct-current connection end is connected to a plurality of direct-current power supplies (see connection to k; Ma). Regarding claim 8, The combination teaches a voltage source multi-level converter, wherein the voltage source multi-level converter topology according to claim 1 is used as a phase bridge arm (see Fig. 2; Ma). Regarding claim 9, The combination teaches wherein different bridge arms share a direct-current side (see Vdc, Fig. 2; Ma). Regarding claim 10, The combination teaches a control method of the voltage source multi-level converter topology according to claim 1, wherein the method comprises the following steps: driving each switch to execute a respective switching state, and generating different current paths from a direct-current end to the alternating-current end, to enable a voltage at the alternating-current end to present different levels (please see the rejection set forth in claim 1; Ma). Claims 5 and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Ma in view of Liu (CN 113726206) Regarding claim 5, The combination teaches the voltage source multi-level converter topology according to claim 1. However, The combination does not disclose wherein the direct-current connection end is connected to a single direct-current power supply and three split direct-current capacitors. Yet, Liu in the same filed teaches the direct-current connection end is connected to a single direct-current power supply and three split direct-current capacitors (see Cd1, Cd2 and Cd3, Fig. 2). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Ma and Lu with the teachings of Liu by having the direct-current connection end is connected to a single direct-current power supply and three split direct-current capacitors in order to increased voltage handling, better filtering of high-frequency noise, and improved energy storage capacity. Regarding claim 6, the combination teaches, wherein four direct-current connection ends are connected to three direct-current link capacitors, and the capacitors are connected in series and then connected to the direct-current power supply capacitors (see Cd1, Cd2 and Cd3, Fig. 2; Liu). Response to Arguments Applicant's arguments filed 10/31/2025 have been fully considered but they are not persuasive. Regarding applicants argument that the combination does not disclose “each group of half-bridge circuits comprise two direct-current connection ends;" and "all the switches are insulate-gate bipolar transistors (IGBTs)." (Page 4) The examiner respectfully disagrees with applicant. During patent examination The Examiner is required to interpret the claim language under the Broadest Reasonable Interpretation (BRI). Under BRI, a claim term is given its broadest reasonable meaning as it would be understood by someone with ordinary skill in the art at the time of the invention, consistent with the term's ordinary meaning and its use in the patent's specification. Therefore as can be seen below Ma in fact teaches each group of half-bridge circuits comprise two direct-current connection ends; from positive to neutral (+ to O) and from negative to neutral (- to O). Hence each group of half-bridge circuits comprise two direct-current connection ends. PNG media_image1.png 860 973 media_image1.png Greyscale Further, regarding applicant all the switches are insulate-gate bipolar transistors (IGBTs), the prior art Lu expresses that it is known to have a T-Type multi-level topology using only IGBT switches. Further it has been recognized that the substitution of one known element for another that would have yielded predictable results to one of ordinary skill in the art at the time of the invention is considered obvious and not inventive nor novel. In conclusion the combination of the prior art teaches all of the limitations as currently drafted claims. Further any minor differences between the combination of the prior art and the current claims would flow naturally to one of ordinary skill in the art without any novelty nor an inventive step. In order to expedite the prosecution of this application The Examiner suggest that applicant amend the claims by including structural components that are different from the prior art applied in order to distinguish the claim invention from the prior art of record. Conclusion THIS ACTION IS MADE FINAL. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ELIM ORTIZ whose telephone number is (571)270-7114. The examiner can normally be reached 9:30am-6:30pm. 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, Rexford Barnie can be reached at (571) 272-7492. 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. /ELIM ORTIZ/Primary Examiner, Art Unit 2836
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Prosecution Timeline

Mar 04, 2024
Application Filed
Jun 28, 2025
Non-Final Rejection — §103
Oct 31, 2025
Response Filed
Nov 15, 2025
Final Rejection — §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

3-4
Expected OA Rounds
79%
Grant Probability
99%
With Interview (+22.9%)
2y 11m
Median Time to Grant
Moderate
PTA Risk
Based on 567 resolved cases by this examiner. Grant probability derived from career allow rate.

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