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 .
Response to Arguments
Applicant's arguments filed 24 February 2026 have been fully considered but were not persuasive.
Applicant argues that El Moursi modified by Andresen does not explicitly disclose “controlling the converter based on a set point value representative of a voltage level of the DC voltage intermediate circuit”, as now required by independent claims 1, 13, and 14. Applicant states that the instant invention actively controls based on the setpoint value. First, it is pointed out that “active” control is not in the claims, nor does it appear in the specification. Second, it appears that Andresen carries out a similar “active” control, especially when coupled with paragraph 0106, as stated below. Applicant argues that Andresen teaches a passive control because it operates the grid side converter as a mere rectifier during times when the DC chopper is needed. However, this is all that the control of Andresen is needed to do at this point of the control, the converter is actively controlled to become and to cease being a rectifier. If there is an overvoltage, the control will dissipate the power, and when that dissipation is done, Andresen switches operation, this is an active change. If Applicant believes the converter of the instant invention is operating differently, the claims should be further amended.
Regardless, as now reflected in the rejection below, Andresen teaches controlling the DC-link voltage to a setpoint, this explicitly teaches the new amendment to claim 1. Lastly, as this is all part of the overvoltage protection of Andresen, that is not explicitly disclosed in El Moursi, the skilled artisan would look to Andresen in an effort to protect the system of El Moursi from possible damage in overvoltage situations.
Claim Rejections - 35 USC § 103
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 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, 11, and 14-15 are rejected under 35 U.S.C. 103 as being unpatentable over El Moursi et al. (“El Moursi”; US 2014/0138949), in view of Andresen et al. (“Andresen”; US 2013/0193933).
Regarding claim 1: El Moursi discloses a method for controlling a converter (318, 320, 322; Fig. 3), wherein the converter is configured to be connected to a rotor of a doubly-fed induction generator (304) for feeding electrical power into an electrical grid (Fig. 4), the converter including a machine-side inverter (318, Fig. 3), a grid-side inverter (324), and a DC voltage intermediate circuit (322) having a protection element (320) for dissipating power from the DC voltage intermediate circuit, the method comprising:
obtaining information representative of the electrical power supplied by the generator to the electrical grid exceeding a target power value beyond a predetermined threshold (Fig. 6, steps 604-606).
El Moursi does not explicitly disclose controlling the converter based on a set point value representative of a voltage level of the DC voltage intermediate circuit in response to obtaining said information, such that the grid-side inverter draws power from a grid-side AC bus and supplies said power from the grid-side AC bus to the protection element so as to dissipate power from the DC voltage intermediate circuit and so increase power dissipation for the doubly-fed induction generator.
However, Andresen discloses controlling the converter based on a set point value representative of a voltage level of the DC voltage intermediate circuit (paragraph 0106) in response to obtaining said information, such that the grid-side inverter (141) draws power from a grid-side AC bus (156) and supplies said power from the grid-side AC bus to the protection element (127,129) so as to dissipate power from the DC voltage intermediate circuit (115) and so increase power dissipation for the doubly-fed induction generator (paragraph 0088: during a grid overvoltage, the choppers 127,129, dissipate energy from the utility grid).
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 system of El Moursi to dissipate power from the grid side of the DC link, as disclosed by Andresen, in order to overcome a transient overvoltage of grid (paragraph 0088).
Regarding claim 2: El Moursi discloses said information represents a grid fault (paragraph 0026).
Regarding claim 3: El Moursi discloses said information represents a grid connection interruption (paragraph 0026).
Regarding claim 4: El Moursi discloses said information further indicates a weak grid connection point (paragraph 0026).
Regarding claim 11: El Moursi discloses said adapting at least one of the set point value and the threshold value such that the set point value is above the threshold value includes:
obtaining a second parameter representative of at least one of a voltage level at the grid connection point and the electrical power supplied by the generator to the grid (paragraph 0048 the GSC Controller takes in the grid voltage); and,
determining, based on the second parameter, the set point value such that the grid-side inverter supplies a predetermined amount of power to the protection element (as the PWM controller controls the output of the GSC, which is inherently provided to the protection element as the protection element is connected to the DC link).
Regarding claim 14: El Moursi discloses an apparatus for controlling a converter wherein the converter is configured to be connected to a rotor of a doubly-fed induction generator (304) for feeding electrical power into an electrical grid (Fig. 4), the converter including a machine-side inverter (318, Fig. 3), a grid-side inverter (324), and a DC voltage intermediate circuit (322) having a protection element (320) for dissipating power from the DC voltage intermediate circuit, the apparatus being configured to:
obtain information representative of the electrical power supplied by the generator to the electrical grid exceeding a target power value beyond a predetermined threshold (Fig. 6, steps 604-606).
El Moursi does not explicitly disclose controlling the converter based on a set point value representative of a voltage level of the DC voltage intermediate circuit in response to obtaining said information, such that the grid-side inverter draws power from a grid-side AC bus and supplies said power from the grid-side AC bus to the protection element so as to dissipate power from the DC voltage intermediate circuit and so increase power dissipation for the doubly-fed induction generator.
However, Andresen discloses controlling the converter based on a set point value representative of a voltage level of the DC voltage intermediate circuit (paragraph 0106) in response to obtaining said information, such that the grid-side inverter (141) draws power from a grid-side AC bus (156) and supplies said power from the grid-side AC bus to the protection element (127,129) so as to dissipate power from the DC voltage intermediate circuit (115) and so increase power dissipation for the doubly-fed induction generator (paragraph 0088: during a grid overvoltage, the choppers 127,129, dissipate energy from the utility grid).
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 system of El Moursi to dissipate power from the grid side of the DC link, as disclosed by Andresen, in order to overcome a transient overvoltage of grid (paragraph 0088).
Regarding claim 15: El Moursi discloses a system comprising a wind turbine, the doubly-fed induction generator, the converter and the apparatus for controlling the converter of claim 14, the generator including the rotor and a stator, the converter including the machine-side inverter connected to the rotor, the grid-side inverter, and the DC voltage intermediate circuit including a protection element for dissipating power from the DC voltage intermediate circuit, wherein the stator and the grid-side inverter are configured to be connected to an electrical grid for feeding electrical power into the electrical grid (see rejection of claims 1 and 14, above).
Claims 5-10 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over El Moursi and Andresen as applied to claim 1 above, and further in view of Gupta et al. (“Gupta”; US 2011/0163546).
Regarding claim 5: El Moursi modified by Andresen discloses the grid-side inverter is configured to be controlled based on the set point value representative of the voltage level of the DC voltage intermediate circuit (Andresen, paragraph 0106), but does not explicitly disclose the protection element is configured to be controlled based on a threshold value representative of a maximum voltage level of the DC voltage intermediate circuit; and, said controlling the converter in response to obtaining said information includes adapting at least one of the set point value and the threshold value such that the set point value is above the threshold value.
However, Gupta discloses the protection element is configured to be controlled based on a threshold value representative of a maximum voltage level of the DC voltage intermediate circuit (510, Fig. 7); and,
said controlling the converter in response to obtaining said information includes adapting at least one of the set point value and the threshold value such that the set point value is above the threshold value (520, Fig. 7, as the duty cycle being set to 1 is activating the DC voltage intermediate circuit, also paragraph 0029).
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 protection element control of El Moursi to have the steps of Gupta in order to better protect the system.
Regarding claim 6: El Moursi modified by Gupto discloses said adapting at least one of the set point value and the threshold value, but do not explicitly disclose the set point value is above the threshold value includes increasing the set point value.
However, it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art, In re Antonie, 195 USPQ 6 (C.C.P.A. 1977).
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 threshold value to increase in order to design an optimal system.
Regarding claim 7: El Moursi modified by Gupto discloses said adapting at least one of the set point value and the threshold value, but do not explicitly disclose the set point value is above the threshold value includes decreasing the set point value.
However, it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art, In re Antonie, 195 USPQ 6 (C.C.P.A. 1977).
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 threshold value to decrease in order to design an optimal system.
Regarding claim 8: El Moursi modified by Gupta disclose controlling the protection element, Gupta further discloses the protection element is configured to be activated and deactivated based on a duty cycle value (520, Fig .7); and,
said controlling the converter in response to obtaining said information includes: obtaining a first parameter representative of a voltage level of the DC voltage intermediate circuit (500); and,
determining, based on the first parameter, the duty cycle value such that the protection element dissipates a predetermined amount of power from the DC voltage intermediate circuit (510).
Regarding claim 9: El Moursi modified by Gupta disclose controlling the protection element based on a duty cycle, Gupta further discloses the duty cycle value is determined based on a voltage level difference between the first parameter and the set point value by applying a characteristic (paragraphs 0079-0080).
Regarding claim 10: El Moursi modified by Gupta disclose controlling the protection element based on a duty cycle and applying a characteristic, Gupta further discloses the characteristic is predetermined based on a short circuit ratio, value at the grid connection point of the generator, a characteristic value of the protection element, and a rated voltage level of the DC voltage intermediate circuit (in this case, the characteristic of the protection element – paragraph 0080: the power difference threshold).
Regarding claim 12: El Moursi discloses a target power value, but does not explicitly disclose the target power value encompasses a target power output for drive train oscillation damping; and said determining the set point value such that the grid-side inverter supplies a predetermined amount of power to the protection element includes: determining the set point value based on the target power value.
However, Gupta discloses the target power value encompasses a target power output for drive train oscillation damping (last sentence paragraph 0064, the object of the control of the chopper circuit is to mitigate drive train oscillations); and said determining the set point value such that the grid-side inverter supplies a predetermined amount of power to the protection element includes:
determining the set point value based on the target power value (paragraph 0063-0064, the chopper, or protection element, is only activated based on power imbalance, from oscillations).
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 system of El Moursi to mitigate drive train oscillations, as disclosed by Gupta, in order to reduce drive train damage (paragraph 0006).
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over El Moursi, in view of Andresen and Gupta.
Regarding claim 13: El Moursi discloses a method for controlling a converter (318, 320, 322; Fig. 3), wherein the converter is configured to be connected to a rotor of a doubly-fed induction generator (304) for feeding electrical power into an electrical grid (Fig. 4), the converter including a machine-side inverter (318, Fig. 3), a grid-side inverter (324), and a DC voltage intermediate circuit (322) having a protection element (320) for dissipating power from the DC voltage intermediate circuit.
El Moursi does not explicitly disclose obtaining information representative of a target power output for drive train oscillation damping; and, controlling the converter based on a set point value representative of a voltage level of the DC voltage intermediate circuit based on the obtained information, such that the grid-side inverter draws power from a grid-side AC bus and supplies said power from the grid-side AC bus to the protection element so as to dissipate power from the DC voltage intermediate circuit.
However, Gupta discloses obtaining information representative of a target power output for drive train oscillation damping (last sentence paragraph 0064, the object of the control of the chopper circuit is to mitigate drive train oscillations).
And, Andresen discloses controlling the converter based on a set point value representative of a voltage level of the DC voltage intermediate circuit (paragraph 0106) in response to obtaining said information, such that the grid-side inverter (141) draws power from a grid-side AC bus (156) and supplies said power from the grid-side AC bus to the protection element (127,129) so as to dissipate power from the DC voltage intermediate circuit (115) and so increase power dissipation for the doubly-fed induction generator (paragraph 0088: during a grid overvoltage, the choppers 127,129, dissipate energy from the utility grid).
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 system of El Moursi to mitigate drive train oscillations, as disclosed by Gupta, in order to reduce drive train damage (paragraph 0006) and to modify the system of El Moursi to dissipate power from the grid side of the DC link, as disclosed by Andresen, in order to overcome a transient overvoltage of grid (paragraph 0088).
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 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