DETAILED ACTION
This Office action is in response to the application filed on 14 January 2025.
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.
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 1,2,8,10 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Buchmann Beat et. al (WO2019096417A1; hereafter “Beat”) in view of Ramin Razani et. al (IEEE Journal of Emerging and Selected Topics in Power Electronics, Volume: 9, Issue: 5, October 2021; hereafter “Ramin”).
-Regarding claim 1:
Beat discloses:
PNG
media_image1.png
644
986
media_image1.png
Greyscale
A direct multi-to-single-phase (description; “Figure 1 shows a converter arrangement 1 comprising an MMC 10 and a converter controller 16, as well as a first (here three-phase) transformer 14a and a second (here single-phase) transformer 14b.”), modular multi-level converter (Fig. 1; 10), comprising: a first alternating current interface for connecting the MMC to a multi-phase (Fig. 1; 14a), first power grid with a first given voltage, in particular a three-phase power grid (Fig. 1; distribution grid A,B, C); a second AC interface for connecting the MMC to a single-phase (Fig. 1; 14b), second power grid with a second given voltage (Fig. 1; red arrow); a first group of P phase-legs (Fig. 1; 12a), wherein each phase-leg of the first group comprises N switching cells (Fig. 1; 13) connected in series between a respective one of P phases (Li1, L2, L3) of the first AC interface (Fig. 1; blue arrow) and a single phase of the second AC interface (Fig. 1; red circle), wherein P>2 and N>3 (Fig. 1); a second group of P phase-legs (Fig. 1; 12b), wherein each phase-leg of the second group comprises N switching cells (Fig. 1; 13) connected in series between a respective one of the P phases (Li, L2, L3) of the first AC interface (Fig. 1; blue arrow) and a neutral potential (Fig. 1; blue circle) of the second AC interface;
However, Beat does not disclose the operation of a controller in a multi to single phase MMC power converter.
Ramin, in the same field of endeavor, discloses:
Ramin discloses:
and at least one controller (Fig. 1; 16), configured to control (paragraph III-C;” each phase leg has its own controller equipped with the proposed fault-tolerant approach. Each phase-leg controller operates almost independently of the other phase-leg controllers. Therefore, the proposed fault-tolerant approach can be implemented in the dc/dc MMC with any number of phase legs by simply adding the fault-tolerant algorithm to the phase-leg controller.”) the first group of P phase-legs (Fig. 1; 12a) and the second group of P phase-legs (Fig. 1; 12b) to selectively provide a maximum apparent power at the first AC interface and at the second AC interface (paragraph III-A; “basic idea is to find the gap between the maximum arm peak voltage generated by the controller and the maximum voltage”), and, in response to the detection of at least one failed switching cell (abstract; “modular multilevel converter (MMC) in the case of submodules (SMs) faults.” , and Fig. 2) of a first phase-leg, to switch the MMC into a limited output mode of operation (abstract; “degraded performance or reduced power transmission.”), wherein the MMC provides a reduced maximum apparent power at the first AC interface and/or at the second AC interface by controlling at least the first phase-leg, based on a tuning factor kJpa, to output a reduced phase-leg voltage UmaxphLeg,pk , thereby reducing a reactive power at the first AC interface and at the second AC interface (abstract;” This feature allows the converter to reduce the number of SMs needed in each arm at the cost of degraded performance or reduced power transmission.”, and the tuning factor is related with the number of SM.).
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 described in Beat such that a commonly used control method according to a number of failed switching cells described in Ramin is applied to the multi to single phase MMC power converter. Doing so allows for improving the control of the multi to single phase MMC power converter with the failed switching cells.
-Regarding claim 2:
Ramin discloses:
The MMC according to claim 1, wherein the MMC is configured to, in a normal mode of operation with no failed switching cell, selectively provide the maximum apparent power at the first AC interface and at the second AC interface using all of the 2NP switching cells (paragraph III-A;” If SM fault occurs in this arm, the existing redundant SMs empower the faulty arm to generate the same arm voltage as in the prefault condition. Therefore, the converter can continue its operation with maximum arm ac voltage despite SM failure.”); and in the limited output mode of operation with at least one failed switching cell, in particular a N-1 mode of operation with one failed switching cell, selectively provide the reduced maximum apparent power at the first AC interface and at the second AC interface using a subset of the switching cells (abstract; “This feature allows the converter to reduce the number of SMs needed in each arm at the cost of degraded performance or reduced power transmission.”) excluding the at least one failed switching cell.
-Regarding claim 8:
Ramin discloses:
The MMC according to claim 1, comprising: a converter-level control unit, configured to determine a number cells in operation (Fig. 7, and paragraph III-E;” The first action to take after the fault detection is to remove the faulty SM from the sorting algorithm.”) and to determine, based on the number cells in operation, a maximum phase-leg voltage each phase-leg of the first and second groups (paragraph III-B; ” When n f SMs fail in the lower arm, the maximum voltage that can be generated reduces to VDC2 − n f · VCN.”); and at least one phase-leg-level control unit, configured to modulate the maximum voltage and select at least a subset of the cells in operation (abstract; ” This feature allows the converter to reduce the number of SMs needed in each arm at the cost of degraded performance or reduced power transmission.”).
-Regarding claim 14:
Ramin discloses:
The method of claim 1, wherein the remaining switching cells of the plurality of phase-legs are controlled to limit their capacitive reactive power in response to detecting that at least one switching cell of a first phase-leg has failed (table 1, and paragraph II-B; “As shown in Fig. 2, an open-circuit fault can occur in either of S1 and S2 switches; and based on the arm current direction and SM status, it can change the behavior of the faulty SM. To investigate this, Table I is provided where the SM capacitor voltage vc and the SM output voltage vSM are analyzed in various conditions.”).
For method claims 10, 13, 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 is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device “1 inherently performs the claimed process. In re King, 801 F.2d 1324, 231 UPSQ 136 (Fed Cir. 1986). Therefore, the previous rejections based on the apparatus will not be repeated.
Allowable Subject Matter
Claims 3-7, 9,11,12,15,16 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.
The following is a statement of reasons for the indication of allowable subject matter:
-with respect to claim 3:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about a specific equation for a maximum peak output voltage.
-with respect to claim 5:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about a specific range of tuning factor.
-with respect to claim 6:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about a specific equation of a virtual DC-link reference voltage.
-with respect to claim 7:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about 1/3-phase converter voltages based on normal and reduced voltages.
-with respect to claim 9:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about a three to single phase, AC/AC railway intertie.
-with respect to claim 11:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose that the tuning factor kph is predetermined before a failure of the at least one switching cell is detected.
-with respect to claim 12:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about the method to obtain the maximum apparent power of the MMC and to operate the MMC in the limited output mode. power of the MMC.
-with respect to claim 15:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about the injection of an inductive reactive power in response to detecting the at least one failed switching cell.
-with respect to claim 16:
the prior arts in Beat, and Ramin disclose the claimed invention in basic claims but do not further disclose about a specific range of tuning factor.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEUNG HO CHOI whose telephone number is (571)272-8188. The examiner can normally be reached Monday-Thursday, 7:30 AM - 5:30 PM ET.
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 at 571-270-1682. 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.
/SEUNG HO CHOI/Examiner, Art Unit 2838
/CRYSTAL L HAMMOND/Supervisory Primary Examiner, Art Unit 2838
Prosecution Insights