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 .
Drawings
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the rotational speed reference is set such that a stator current and/or a rotor current of the asynchronous generator system is maintained substantially constant upon change, decrease, of the utility grid voltage of claim 5 and the rotational speed reference is set such that a product of the utility grid voltage and the rotational speed reference is maintained substantially constant upon change, decrease, of the utility grid voltage of claim 6 must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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 2, 5-6, 8, 10, and 13 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.
Regarding claim 2: The last two lines recite “below a nominal grid voltage, below by between 0.1% and 10% of a nominal grid voltage.” First, this somewhat awkward English. Regardless, “a nominal grid voltage” is repeated twice. It is unclear if they are the same or different nominal grid voltages.
Regarding claim 5: The last two lines recite “…constant upon change, decrease, of the utility grid voltage.” This is unclear, or possibly a typographical error.
Regarding claim 6: The last two lines recite “…constant upon change, decrease, of the utility grid voltage.” This is unclear, or possibly a typographical error.
Regarding claim 8: The last two lines recite “a width between 1 min and 20 minutes, further between 3 min and 10 minutes.” It is unclear if “further between 3 min and 10 minutes” is required by the claim.
Regarding claim 10: Line 2 recites “a wind turbine”, this has already been introduced in claim 1. It is unclear if it is the same or different wind turbine.
Regarding claim 13: Line 2 recites “a wind turbine” and “a utility grid”, line 4 recites “a rotational speed reference”, and line 5 recites “a utility grid voltage”. All these limitations have been introduced in claim 1. It is unclear if they are the same or different limitations.
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.
Claims 1-6, 9-10, and 13-14 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Letas (US 2019/0214927).
Regarding claim 1: Letas discloses a method of controlling an asynchronous generator system (Fig. 1, paragraph 0039) of a wind turbine (Fig. 1), connected to a utility grid (8), the method comprising:
setting a rotational speed reference (n, Fig. 3) of the asynchronous generator system in dependence of a utility grid voltage (U_rotor of Fig. 3 is implicitly correlated to the grid voltage since the rotor voltage is provided to the grid, regardless, claim 1 of Letas states that the rotation rate parameter is associated with the grid parameters, and claim 3 states that a grid parameter is grid voltage).
Regarding claim 2: Letas discloses the method performed in an undervoltage situation, where the utility grid voltage decreases below or is below a nominal grid voltage (as Fig. 3 shows the left side of the Voltage decreasing to 0, which implies it will fall below a nominal grid voltage), below by between 0.1 % and 10% of a nominal grid voltage (as the slope goes all the way to 0, it will inherently go through this range).
Regarding claim 3: Letas discloses wherein setting the rotational speed reference (n) comprises:
increasing the rotational speed reference (n), if the utility grid voltage decreases, by at least a threshold over at least a minimum time interval (Fig. 3 shows the rotational speed reference increasing from n = 500-900, while the grid voltage decreases).
Regarding claim 4: Letas discloses wherein the rotational speed reference (n) is set in dependence of a ratio between the nominal grid voltage and the utility grid voltage (as Fig. 3 depicts the voltage from a max to 0, which inherently includes a ratio between a nominal grid voltage and the utility grid voltage).
Regarding claim 5: Letas discloses wherein the rotational speed reference is set such that a stator current and/or a rotor current of the asynchronous generator system is maintained substantially constant upon change, decrease, of the utility grid voltage (paragraph 0066: the frequency or speed is set so the stator and rotor current remains constant during grid transients).
Regarding claim 6: Letas discloses wherein the rotational speed reference is set such that a product of the utility grid voltage and the rotational speed reference is maintained substantially constant upon change, decrease, of the utility grid voltage (in other words the rotation speed is proportional to the grid voltage decrease, this is inherent because the output voltage must match the grid voltage).
Regarding claim 9: Letas discloses:
controlling the generator system according to the rotational speed reference (paragraph 0002).
Regarding claim 10: Letas discloses wherein the asynchronous generator system (Fig. 1) is driven by a rotor (2) of a wind turbine at which plural rotor blades (unlabeled, but clear in Fig. 1) are mounted, the wind turbine comprising a blade pitch adjustment system (paragraph 0050) for adapting at least one blade pitch angle, wherein controlling the generator according to the rotational speed reference comprises:
determining, based on the rotational speed reference (n), a blade pitch adjustment system reference , comprising at least one of:
blade pitch angle reference (such as the “nominal speed” or the “maximum speed”, paragraph 0050); and/or
a mechanical power reference; and/or
a mechanical torque reference (such as the torque reaching its highest value, paragraph 0050);
supplying the blade pitch adjustment system reference to the blade pitch adjustment system (inherent as the control is carried out).
Regarding claim 13: Letas discloses a controller (inherent) for controlling an asynchronous generator system (1), in particular of a wind turbine (Fig. 1), connected to a utility grid (8), the controller being configured:
to set a rotational speed reference (n) of the asynchronous generator system in dependence of a utility grid voltage (U_rotor of Fig. 3 is implicitly correlated to the grid voltage since the rotor voltage is provided to the grid, regardless, claim 1 of Letas states that the rotation rate parameter is associated with the grid parameters, and claim 3 states that a grid parameter is grid voltage), the controller being configured to control or carry out a method according to claim 1.
Regarding claim 14: Letas discloses the wind turbine (Fig. 1), comprising:
an asynchronous generator system (1, paragraph 0002); and
a controller according to claim 13 (see rejection of claim 13, above).
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 7 is rejected under 35 U.S.C. 103 as being unpatentable over Letas, in view of Brombach et al. (“Brombach”; US 2021/0265841).
Regarding claim 7: Letas discloses the method further comprising:
measuring the utility grid voltage, but does not explicitly disclose measuring the utility grid voltage at a point of common coupling to which plural wind turbines are connected or directly at the generator terminals.
However, Brombach discloses measuring the utility grid voltage (paragraph 0115, there is a controller present at the PCC) at a point of common coupling (‘PCC’, 118, Fig. 2) to which plural wind turbines are connected or directly at the generator terminals (100).
Therefore, it would have been obvious for one of ordinary skill in the art, before the effective filing date of the invention to modify the generator system of Letas to include the plural turbines and PCC of Brombach in order to provide additional power.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Letas and Brombach, as applied to claim 7 above, further in view of Dong et al. (“Dong”; US 2023/0031139).
Regarding claim 8: Letas discloses the generator system, but does not explicitly disclose the method further comprising at least one of:
low pass filtering the measured grid voltage;
averaging the measured grid voltage over a moving time window, the time window having a width of between 1 min and 20 minutes, further between 3 min and 10 minutes.
However, Dong discloses the method further comprising at least one of:
low pass filtering the measured grid voltage (paragraph 0010);
averaging the measured grid voltage over a moving time window (also paragraph 0010), the time window having a width of between 1 min and 20 minutes, further between 3 min and 10 minutes.
Therefore, it would have been obvious for one of ordinary skill in the art, before the effective filing date of the invention to modify the generator system of Letas to low pass filter the grid voltage, as disclosed by Dong, in order to make the control more robust.
Claims 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Letas, in view of Mikhail et al. (“Mikhail”; US 6,137,187).
Regarding claim 11: Letas discloses the asynchronous generator system (Fig. 1) comprising:
an asynchronous generator (1) having multiple phase stator windings (within 7) and having multiple phase rotor windings (within 3);
a converter (4) connected to the rotor windings and configured to convert a variable frequency rotor power stream to fixed frequency rotor power stream at converter output terminals connected to the utility grid (this is the purpose of a converter);
the stator windings being connected to the utility grid (8),
Letas does not explicitly disclose wherein controlling the generator according to the rotational speed reference comprises: determining, based on the rotational speed reference, a converter reference, comprising at least one of: a converter power reference; a converter torque reference. supplying the converter reference to the converter.
However, Mikhail discloses wherein controlling the generator according to the rotational speed reference comprises:
determining, based on the rotational speed reference (column 12, line 10, the controller maintains the speed), a converter reference, comprising at least one of:
a converter power reference;
a converter torque reference (column 12, lines 29-38: during gusts, based on the generator speed, the converter maintains the correct output to the grid).
supplying the converter reference to the converter (inherent).
Therefore, it would have been obvious for one of ordinary skill in the art, before the effective filing date of the invention to modify the generator system of Letas to include the converter control of Mikhail in order to ensure the output voltage matches the grid voltage.
Regarding claim 12: Letas discloses wherein the asynchronous generator comprises at least one of:
a doubly fed induction generator (paragraph 0002).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEAN GUGGER whose telephone number is (571)272-5343. The examiner can normally be reached M-Th 9:00am - 5:00pm EST.
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/SEAN GUGGER/ Primary Examiner, Art Unit 2834
