DETAILED ACTION
Status of Claims
Claims 1 – 7 are pending.
Claim 1 is independent.
This office action is Non-Final.
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 .
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.
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.
Claims 1 – 3 are rejected under 35 U.S.C. 103 as being unpatentable over Fujii et al. (US Patent Application Publication No. 2024/0275165, hereinafter “Fujii”) in view of Suzuki et al. (US Patent Application Publication No. 2022/0399801 A1, hereinafter “Suzuki”).
As per claim 1, Fujii teaches a power converter [power converter 110, fig.1, 0002 – 0003, 0018, 0039] that is interconnected with a power system to operate as a virtual synchronous generator [virtual synchronous machine, 0002, 0018: The power converter with virtual synchronous machine control (hereinafter also referred to as “virtual synchronous machine) is controlled so as to simulate the behavior of a synchronous generator to be simulated being connected to a power grid… Power converter 110 is a power converter connected to power storage element 130 to perform power conversion between power storage element 130 and power grid 2. …. Power converter 110 thus charges and discharge power of power storage element 130.], the power converter comprising:
a power conversion circuit [power converter 110, fig.1 , 0017 - 0018];
… a control device configured to control an output voltage outputted from the power conversion circuit to the power system [controller 8], the control device including:
a voltage amplitude command calculation unit [voltage regulating unit 17, fig. 3, 0056 – 0060] configured to calculate an amplitude command value for the output voltage [induction voltage generation unit 10];
a frequency command calculation unit configured to calculate a first frequency command value, based on a rated frequency of the power system, and to set the first frequency command value as a frequency command value for the output voltage [generator stimulating unit 153; integrator 21 outputs angular frequency deviation from swing equation; adder outputs the frequency command];
a current command calculation unit configured to calculate a first current command value, based on the amplitude command value for the output voltage, the frequency command value for the output voltage, the output voltage, and an output current that is outputted to the power system, and to set the first current command value as a current command value for the output current [coordinate transformation units 13/14 compute Id, Iq, and Icnd, Icnq from measurements 0056]; and
a voltage command calculation unit configured to generate a command value for the output voltage, based on the current command value for the output current, a filter current having flowed in the filter, and the output voltage, wherein the current command calculation unit is configured to, responsive to a magnitude of the first current command value exceeding an upper limit value, calculate a second current command value by restricting the magnitude of the first current command value to the upper limit value [clamping current magnitude to an upper limit 0067 - 0069], and to set the second current command value as the current command value for the output current [adders 44/45 generate final voltage command values Vdref/Vqref by adding the unsuppressed voltage command 0067-0069, 0070-0073, fig. 3 -4].
However, Fujii does not explicitly teach the filter. Suzuki is cited to teach suppressing an overcurrent using, in part, at LC filter. Both Fujii and Suzuki are directed toward overcurrent protection.
As per claim 1, Suzuki teaches a filter provided between the power system and the power conversion circuit [an LC filter, 0050, 0052, fig. 1, fig. 2].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine Fujii and Suzuki, as Suzuki added more protection from overcurrent using a filter.
As per claim 2, Fujii teaches the power converter according to claim 1, wherein the current command calculation unit is configured to, responsive to the magnitude of the first current command value exceeding the upper limit value, decrease the upper limit value according to a time period having elapsed since the magnitude of the first current command value exceeds the upper limit value [0064 – 0066, 0076, 0081 – 0090, fig. 5, and 6].
As per claim 3, Fujii teaches the power converter according to claim 2, wherein the current command calculation unit decreases the upper limit value in a stepwise manner [0076 – 0080, 0091 – 0096: the overcurrent level is inherently discrete/stepwise(level 1a, 1b, 2, 3,…N and each level maps to a discrete limit value in fig.5].
Allowable Subject Matter
Claims 4 – 7 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.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Engelhardt; Stephan et al. (US Patent Application Publication No. 2009/0267572 A1) “Current Limitation For A Double-Fed Asynchronous Machine” is cited to teach a method and an apparatus for controlling the output or drawn active and reactive power of a double-fed asynchronous machine (5), the maintenance of a maximum permissible current (16) of the machine--without the use of a subordinate current controller--is ensured by virtue of the fact that, during the operation of the double-fed asynchronous machine, a maximum permissible desired value for the active power (10a) to be output or to be drawn and a maximum permissible desired value for the reactive power (10b) to be output or to be drawn are calculated with the aid of a model of the asynchronous machine from the maximum permissible current (16), preferably corrected at least using the actual value of the current to be limited of the machine, in such a way that the maximum permissible current (16) is not exceeded; The predetermined active and reactive power desired values are then limited to the calculated maximum permissible values.
Choi; Seung-Cheol et al. (US Patent No. 10,141,881) “Apparatus For Controlling Inverter” is cited to teach an apparatus for controlling the inverter contained in an inverter system configured to drive a motor determines a slip frequency to be used for compensation of a frequency of a first reference voltage, not only using a first reference voltage (including an amplitude and frequency) of the first reference voltage applied to the inverter, but also using an output current of the motor or a rotor speed of the motor. The apparatus determines not only a frequency of a second reference voltage obtained by compensation of the slip frequency, but also an amplitude of the second reference voltage corresponding to the frequency of the second reference voltage.
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/TERRELL S JOHNSON/Primary Examiner, Art Unit 2176
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