DETAILED ACTION
This Office action is in response to the preliminary amendment filed on 24 April 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 .
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.
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
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.
Claims 11 and 14 are 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 11 recites that “the first filtering function and the second filtering function are realized by a filtering unit from a list comprising ...”. The term “comprising” is interpreted as open-ended and does not exclude additional, unrecited elements—see MPEP 2111.03. Thus the scope of claim 11 is indefinite because the list of filtering units from which the filtering functions may be selected can include any number of additional options beyond those actually recited in the claim. It is suggested that Applicant change “comprising” to “consisting of”, or otherwise amending the claim to have a definite scope.
For purpose of examination, the filtering functions in claim 11 are interpreted as being limited to the options recited in the list.
Claim 14 sets forth that “a central control unit of the device [of claim 13] is configured to perform steps of claim 13 for feeding the electric power”. However, it is not clear which steps are to be performed by the central control unit. For instance, claim 13 recites a step of “feed[ing] in the electric power based on the frequency-dependent set-point power portion”; it is not clear whether the central control unit of claim 14 is being required to perform just this step, or if it is to perform some larger group of steps from claim 13.
For purposes of examination, the central control unit of claim 14 is being interpreted as performing all of the steps of claim 13.
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.
Claim(s) 1-4, 11 and 13-14 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Howard et al. (US 2020/03820291; hereinafter “Howard”).
In re claims 1 and 13, Howard discloses a device and method for feeding electric power into an electrical supply grid having a mains voltage with a mains frequency via an infeed unit (method as performed by device of Figs. 2-5), comprising:
detecting the mains frequency ([0010]);
forwarding the mains frequency as a frequency measurement signal (id. and see Fig. 5: Normalized Grid Frequency signal),
filtering the frequency measurement signal into a frequency filter signal using a filtering device with low-pass behaviour ([0010] and Fig. 5: first and second filters 416, 418; see also end of [0056]),
determining a frequency-dependent set-point power portion based on the frequency filter signal (see [0036], [0047], [0058]: controller 202 determines control set-points based on grid conditions determined based on filtered frequencies), and
feeding in the electric power based on the frequency-dependent set-point power portion ([0047]), wherein
to filter the frequency measurement signal using the filtering device with low-pass behaviour, at least one first filtering function and one second filtering function with low-pass behaviour with a first low-pass time constant or a second low-pass time constant are used (Fig. 5 and [0056]: low-pass filters 416 and 418), and
the first filtering function and the second filtering function are entirely or partially interchangeable using at least one of a first weighting factor or a second weighting factor ([0057], [0058]: since the controller can determine different grid conditions based on outputs of either filter 416, 418, the outputs are considered to be interchangeable; the weighting factors are considered to be either 1 (for the filter being used to detect a given condition) or 0 (for the filter not being used to detect the given condition)).
In re claim 2, Howard discloses wherein the first filtering function and the second filtering function operate in parallel to one another ([0056] and Fig. 5: 416, 418),
the first filtering function and the second filtering function are weighted with the first weighting factor or second weighting factor ([0056]-[0058]: the weighting factors are considered to be either 1 (for the filter being used to detect a given condition) or 0 (for the filter not being used to detect the given condition)), and
the first filtering function and the second filtering function are interchangeable by changing at least one of the first weighting factor or the second weighting factor (id.: for instance, the high-bandwidth filter 416 is given weight factor of 1 and low-bandwidth filter 418 is given weight factor of 0 when detecting an HVRT or weak grid condition, and vice-versa when detecting islanded grid condition).
In re claim 3, Howard discloses wherein the first filtering function and second filtering function filter the frequency measurement signal into a first partial filter signal or a second partial filter signal ([0056] and Fig. 5: outputs of 416, 418),
the first partial filter signal and the second partial filter signal, weighted with the first weighting factor or the second weighting factor, are added up to form at least part of the frequency filter signal ([0057], [0058]: the signals are weighted either 1 or 0 depending on grid condition being detected as explained above), and
the first weighting factor and the second weighting factor are changeable (as explained above with respect to claim 2).
In re claim 4, Howard discloses wherein the first weighting factor and the second weighting factor are only changed such that a sum of the first weighting factor and the second weighting factor remains constant ([0057]-[0058]: since the filter functions are weighted either 1 or 0 depending on grid condition being detected as explained above, the sum is always constant at 1).
In re claim 11, Howard discloses wherein the first filtering function and the second filtering function are realized by [...] a filter with a behaviour similar to the PT1 element or the PT2 element (the filters 416/418 are considered to be at least similar to the PT1 or PT2 elements as described in Applicant’s specification because of their low-pass behavior: see [0056]).
In re claim 14, Howard discloses a central control unit of the device (Figs. 2, 5) configured to perform steps of claim 13 for feeding the electric power (as explained above with respects to claims 1 and 13).
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.
Claim(s) 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Howard.
In re claim 5, Howard discloses wherein the second low-pass time constant is chosen depending on a system natural frequency of the electrical supply grid that is coupled with the infeed unit ([0057]: “For example, in an embodiment, the filtering assembly 402 may distinguish HVRT events and/or a weak grid condition (where no significant frequency deviations from nominal are expected) by using the high-bandwidth 416”; thus the low-pass time constant for filter 416 is tuned based on the natural frequency (i.e., 50 or 60 Hz) of the grid).
Howard does not disclose that the second low-pass time constant is larger than a reciprocal of the system natural frequency. However, since the grid conditions that are desired to be detected (HVRT and weak grid) by the low-pass filter 416 are expected to occur without significant deviation from the natural grid frequency, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have tuned the filter’s low-pass time constant appropriately, resulting in the time constant being larger than a reciprocal of the system natural frequency, in order to accurately detect the HVRT and/or weak grid conditions as desired.
Allowable Subject Matter
Claims 6-10, 12 and 15 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.
The following is a statement of reasons for the indication of allowable subject matter:
With respect to claim 6, the closest prior art in Howard discloses the invention according to claim 1 as explained above, but does not further disclose wherein the first low-pass time constants and second low-pass time constant are changeable for adapting to a system change and/or a changed system requirement, subject to the first low-pass time constant remaining smaller than the second low-pass time constants. That is, Howard discloses neither the time constants themselves being changeable, nor that such would be subject to the first time constant remaining smaller than the second.
Furthermore, the additional prior art on record does not suggest an obvious modification to the device or method of Howard that would have resulted in the claimed solution.
With respect to claim 7, the closest prior art in Howard discloses the invention according to claim 1 as explained above, but does not further disclose that, in stable operation, when no grid fault has been identified or, following a grid fault, a stable state has been reached, the first weighting factor is chosen to be greater than the second weighting factor, with the first weighting factor being set at 1 and the second weighting factor being set at 0, in fault-case operation following an identification of the grid fault, the first weighting factor is reduced and the second weighting factor is increased, such that the first weighting factor is reduced to a value in a range from 5% to 20% and the second weighting factor is increased to a value in a range from 80% to 95%, and following the fault-case operation, after a safety period has elapsed or after a stability criterion has been fulfilled, a return to the stable operation is carried out in that the first weighting factor is increased to 1, and the second weighting factor is reduced to 0.
Furthermore, the additional prior art on record does not suggest an obvious modification to the device or method of Howard that would have resulted in the claimed solution.
Claim 8 depends from claim 7 and would be allowable for the same reasons.
With respect to claim 9, the closest prior art in Howard discloses the invention according to claim 1 as explained above, and further discloses wherein the infeed unit is designed as a wind farm having a plurality of wind power installations, and the filtering of the frequency measurement signal via the filtering device and the determination of the frequency-dependent set-point power portion are implemented in a central farm control unit (see Fig. 4A and [0004]). However, Howard does not disclose a set-point power value that is to be fed in is transferred to the wind power installations depending on the frequency-dependent set-point power portion, and the set-point power value is formed as a sum of the frequency-dependent set-point power portion and a set-point fundamental power value.
Furthermore, the additional prior art on record does not suggest an obvious modification to the device or method of Howard that would have resulted in the claimed solution.
Claim 10 depends from claim 9 and would be allowable for the same reasons.
With respect to claim 12, the closest prior art in Howard discloses the invention according to claim 1 as explained above, and further discloses a wind farm with a farm control unit having a farm power controller and with a plurality of wind power installations is used for feeding in the electric power (see Fig. 4A and [0004]). However, Howard does not disclose a cascade controller with three control loops, having an inner control loop, in which each of the wind power installations is configured to adjust an output power to an installation set-point power specified by the farm power controller, a middle control loop, in which the farm power controller is configured to (i) determine the installation power as control variable depending on a comparison between a farm set-point power value and a farm actual power value and (ii) transfer the installation power to the wind power installations as installation set-point power, and an outer control loop, in which, depending on the mains frequency, the set-point power portion and the farm set-point power value is determined as control variable and transferred to the farm power controller, wherein the filtering device with low-pass behaviour for filtering the frequency measurement signal is part of the outer control loop, the second low-pass time constant, if greater than the first low-pass time constant, is chosen such that the outer control loop has a slower time response than at lest one of the middle control loop or the inner control loop if the second weighting factor is chosen to be 1 or is at least dominant compared to the first weighting factor with a value in a range of 80% to 95%, the first low-pass time constant is chosen such that the outer control loop has no slower time response than one or more of the middle control loop and the inner control loop if the first weighting factor is chosen to be 1, or is at least dominant compared to the second weighting factor with a value in the range from 80% to 95%, and the outer control loop, if the first filtering function and the second filtering function were to be bridged, has no slower time response than the one or more of the middle control loop and the inner control loop.
Furthermore, the additional prior art on record does not suggest an obvious modification to the device or method of Howard that would have resulted in the claimed solution.
Claim 15 recites substantially similar limitations as claim 12, but as part of the device invention rather than the method. As such, claim 15 would be allowable for substantially the same reasons as explained above.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
US 2012/0104756 discloses a METHOD FOR OPERATING A WIND TURBINE and is the US equivalent of AU 2010227613, cited by Applicant in an IDS.
US 2020/0119560 discloses a METHOD FOR SUPPLYING ELECTRIC POWER INTO AN ELECTRIC SUPPLY NETWORK BY MEANS OF A CONVERTER-CONTROLLED SUPPLY DEVICE and is the US equivalent of CA 3065883, cited by Applicant in an IDS.
US 2021/0285420 discloses a METHOD FOR CONTROLLING A WIND FARM and is the US equivalent of DE 102018116444, cited by Applicant in an IDS.
US 2022/0049679 discloses OSCILLATION DAMPING IN WIND POWER INSTALLATIONS and is the US equivalent of EP 3954896, cited by Applicant in an IDS.
US 2022/0352723 discloses a METHOD FOR FEEDING ELECTRICAL POWER INTO AN ELECTRICAL SUPPLY GRID and is the US equivalent of EP 4084261, cited by Applicant in an IDS.
US 2025/0233537 discloses a METHOD FOR CONTROLLING THE OPERATION OF A WIND TURBINE AND WIND TURBINE and is the US equivalent of EP 4261409, cited by Applicant in an IDS.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to FRED E FINCH III whose telephone number is (571)270-7883. The examiner can normally be reached Monday-Friday, 8:00 AM - 4:30 PM ET.
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/FRED E FINCH III/Primary Examiner, Art Unit 2838
1 Cited by Applicant in the 23 December 2024 Information Disclosure Statement.
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