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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Specification
The disclosure is objected to because of the following informalities: Page 14, line 14, “MTMV-HVDC” should be “MVMT-HVDC”. Page 16, line 23, “supervisory droop control?” is unclear. Page 16, line 26, “coefficient?” is unclear.
Appropriate correction is required.
The lengthy 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.
Drawings
The drawings were received on June 17, 2025. These drawings are acceptable.
Claim Objections
Claims 5-9 and 21 are objected to because of the following informalities: Claim 9, line 1, “comprising” should be “further comprising”. Claim 6, line 1, “comprising” should be “further comprising”. Claim 7, lines 1-2, “method comprises” should be “method further comprises”. Claim 8, line 1, “comprising” should be “further comprising”. Claim 9, lines 1-2, “method comprises” should be “method further comprises”. Claim 21, line 2, “nodular” should be “modular”. Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 5 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 5 recites the limitation “which may be a Norton equivalent circuit or a
Thevenin equivalent circuit”. It is unclear if the equivalent circuit must be a Norton equivalent circuit or a Thevenin equivalent circuit. For examination purposes, it has been assumed that the equivalent circuit must be a Norton equivalent circuit or a Thevenin equivalent circuit.
Claim Rejections - 35 USC § 102
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 (i.e., changing from AIA to pre-AIA ) 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.
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.
Claim(s) 1, 7, 16-17, and 20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Beerten, Jef et al. “Modeling of Multi-Terminal VSC HVDC Systems With Distributed DC Voltage Control”, IEEE Transactions on Power Systems, Vol 29, No.1, January 2014, pp. 34-42 (Beerten).
As to claim 1, Beerten discloses a method for controlling a plurality of HVDC
converters within a multi-terminal HVDC system (see Abstract), the method comprising: controlling the outputs of the plurality of HVDC converters by providing each HVDC converter with a respective DC voltage reference (see page 36, left hand column, and the end of section A, “value of the converter voltage references before limiting” and Figure 7; U*c’ is the reference voltage of a converter already in the multi-terminal configuration); determining a respective feedback signal for each of the plurality of HVDC converters (I*cq) wherein the feedback signals comprise a modification to the DC voltage reference for the respective converter (the modification can be the increment of Ucd arriving to the adder, or the gain applied by the controller); wherein determining the respective feedback signals comprises analyzing terminal characteristics of each converter (see page 40, section A, first paragraph, lines 3-7, and second paragraph, lines 7-9) and determining an index indicative of a margin against loss of equilibrium (see page 38, left hand column, first paragraph, lines 11-24).
As to claim 7, Beerten discloses droop control (see page 38, right hand column, first paragraph, lines 1-9) and therefore the method of Beerten inherently comprises determining DC voltage droop characteristics for each HVDC converter, in order to use droop control.
As to claim 16, Beerten discloses a controller adapted or configured to perform the method of claim 1 (see Abstract, lines 4-6, cascaded DC voltage control).
As to claim 17, Beerten disclose a plurality of HVDC converters and a controller according to claim 16 (see Abstract, lines 4-6, cascaded DC voltage control at every converter).
As to claim 20, Beerten discloses the at least one HVDC converter comprising at least one voltage source converter (VSC) (see Abstract, lines 1-3).
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Beerten in view of Li, Yujun et al., “Stability Analysis of Droop-Based Converter Using SISO Method From DC Side Perturbation”, IEEE Transactions on Power Delivery, Vol. 36, No. 5, October 2021, pp. 3150-3161 (Li).
As to claim 21, Beerten discloses all of the claimed features, as set forth above,
except for the at least one HVDC converter comprising a modular multilevel converter. Li discloses an HVDC converter comprising a modular multilevel converter (see page 3153, left hand side, fourth paragraph, lines 1-4). It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have used at least one HVDC converter comprising a modular multilevel converter in the method of Beerten, in order to provide higher reliability and lower switching frequency and power losses.
Allowable Subject Matter
Claims 6 and 8-9 are objected to as being dependent upon a base claim that has been objected to, or because of informalities, but would be allowable if rewritten with the informalities corrected.
Claims 2-4, 6, 8-13, 15, and 18-19 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Claim 5 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action.
The following is a statement of reasons for the indication of allowable subject matter:
Claim 2 contains allowable subject matter because none of the prior art of record
discloses or suggests the index quantifying the interactions amongst voltage droops between the plurality of HVDC converters, in combination with the remaining claimed features.
Claim 3 contains allowable subject matter because none of the prior art of record discloses or suggests the index indicating a stability margin against DC power transfer, in combination with the remaining claimed features.
Claim 4 contains allowable subject matter because none of the prior art of record discloses or suggests the modification to the voltage reference is determined to optimize steady state operation of the multi-terminal HVDC system, in combination with the remaining claimed features.
Claim 5 contains allowable subject matter because none of the prior art of record discloses or suggests modelling the terminal characteristics of each HVDC converter as an equivalent circuit based on the effect that HVDC converter has in response to a modification of its voltage reference for a give operating state, wherein the equivalent circuit is a Norton equivalent circuit or a Thevenin equivalent circuit, in combination with the remaining claimed features.
Claim 6 contains allowable subject matter because none of the prior art of record discloses or suggests determining HVDC system characteristics by constructing a matrix of extended impedance of extended matrix of conductance for the system, in combination with the remaining claimed features.
Claim 8 contains allowable subject matter because none of the prior art of record discloses or suggests determining an initial value of equilibrium and normalizing the index against loss of equilibrium, in combination with the remaining claimed features.
Claims 9-10 contain allowable subject matter because none of the prior art of record discloses or suggests determining branch currents and nodal voltages within the system, in combination with the remaining claimed features.
Claim 11 contains allowable subject matter because none of the prior art of record discloses or suggests the multi-terminal HVDC system being a multi-vendor multi-terminal HVDC system, in combination with the remaining claimed features.
Claim 12 contains allowable subject matter because none of the prior art of record discloses or suggests the multi-terminal HVDC system is comprised in an HVDC transmission system, in combination with the remaining claimed features.
Claim 13 contains allowable subject matter because none of the prior art of record discloses or suggests the HVDC converters comprised in an interface or interfaces between one or more HVDC power lines and one or more AC generation systems and/or one or more AC grid networks, in combination with the remaining claimed features.
Claim 15 contains allowable subject matter because none of the prior art of record discloses or suggests determining the respective converter specific feedback signals comprises modelling terminal characteristics of each converter as an equivalent circuit based on or representing the response of that HVDC converter to a modification of its voltage reference for a given operating state, in combination with the remaining claimed features.
Claim 18 contains allowable subject matter because none of the prior art of record discloses or suggests at least one HVDC power line, at least one HVDC converter between the at least one HVDC power line and an offshore wind farm, and at least one HVDC converter between the at least one HVDC power line and an onshore AC grid, in combination with the remaining claimed features.
Claim 19 contains allowable subject matter because none of the prior art of record discloses or suggests the system is a multi-vendor multi-terminal HVDC system, in combination with the remaining claimed features.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HAL KAPLAN whose telephone number is (571)272-8587. The examiner can normally be reached 8:30AM-5:30PM.
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, Taelor Kim can be reached at 571-270-7166. 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.
/HAL KAPLAN/Primary Examiner, Art Unit 2836
