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 .
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) 1, 3, 4, 6, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Yoko et al. (2018/0361859), Matsui (2013/0257152), and Wang et al. (2015/0002121).
Regarding independent claim 1, Yoko teaches (Fig. 1) a DC power distribution system comprising:
an AC-DC converter (10) having a forward power flow function of converting AC power inputted from a power grid (60) to DC power and outputting the DC power to a DC grid (1);
a first sensor which detects generated power of a power generation device (21, 22) connected to the DC grid ([0041]; power generated increases based on bus voltage up to a limit);
a load DC-DC converter (42) which supplies power to a load (52) connected to the DC grid ([0022], [0023]); and
a second sensor which detects power supplied from the DC grid to the load DC-DC converter and the load ([0062]).
Yoko fails to explicitly teach the AC-DC converter being bidirectional and its two operation modes. Matsui teaches a similar DC power distribution system (Fig. 1) to that of Yoko. Matsui teaches an AC-DC converter (4) having forward power flow function (from 41 to 1) and a reverse power flow function of converting DC power from the DC grid (1) to AC power and outputting the AC power to the power grid (41) (Abstract; [0041]).
Matsui also teaches a switchover command generation circuitry (controller, [0006]) which generates a command for switching between two operation modes of the AC-DC converter, wherein
the two operation modes are an operation mode 1 in which the reverse power flow function of the AC-DC converter is enabled, and an operation mode 2 in which the reverse power flow function of the AC-DC converter is disabled (Matsui teaches the AC-DC converter 4 can operate in reverse power flow mode (using 42; mode 1) or disabling 42 (mode 2)),
in the operation mode 1, voltage of the DC grid (i.e. 360V-400V) is set to be higher than a value obtained by multiplying a voltage effective value of the AC power by a square root of 2 ([0049]), and
in a case where the generated power of the power generation device detected by the first sensor is smaller than the power supplied to the load DC-DC converter and the load, which is detected by the second sensor, the switchover command generation unit circuitry reduces the voltage of the DC grid and switches the operation mode of the AC-DC converter from the operation mode 1 to the operation mode 2 ([0050]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have Yoko’s AC-DC converter being bidirectional and controlling it in the way described in Matsui, to allow for Yoko’s DC power distribution system to be able to sell power back to the power company and reduce cost and not waste excess power that is generated by Yoko’s system.
Yoko also teaches a DC power supply DC-DC converter (32) which inputs/outputs charge/discharge power to/from a DC power supply (31) connected to the DC grid (1), wherein
when the operation mode of the AC-DC converter is the operation mode 2, the DC power supply DC-DC converter outputs the discharge power from the DC power supply to the DC grid ([0027] and end of [0041] of Yoko; both Yoko and Matsui teach the AC-DC converter being in mode 2 when power on the DC bus is low and power from the DC power supply needs to be discharged to the DC grid).
Yoko teaches a DC grid voltage command generation circuitry (13, 23, 33) which generates a DC grid voltage command which is voltage to be outputted to the DC grid by the AC-DC converter (based on monitored bus voltage; [0037], [0040]), wherein
the DC grid voltage command generation circuitry generates the DC grid voltage command that minimizes a sum of losses in power conversion in the AC-DC converter, the load DC-DC converter, and the DC power supply DC-DC converter ([0030]).
Yoko fails to explicitly teach minimizing losses by controlling the converters based on loss characteristics stored in storage circuitry. Wang teaches a similar power distribution system to reduce losses in power converters (Abstract) to that of Yoko. Wang also teaches a storage circuitry which stores loss characteristics in power conversion ([0012]) and generating voltage command values for converters that minimize a sum of power losses in power conversion on the basis of the loss characteristics stored in the storage circuitry ([0033]). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement Wang’s storage circuitry with loss characteristics into Yoko’s invention since Yoko was silent as to how their converters are controlled to minimize power losses, and Wang teaches a known example of how power losses are determined and controlled and minimized, and that is a main goal in Yoko’s invention.
Regarding claim 3, Yoko teaches a first threshold (i.e. 50%) for a remaining capacity of the DC power supply and a second threshold (i.e. 49.5%) smaller than the first threshold are set in advance, and
in a state in which the operation mode of the AC-DC converter is the operation mode 2, if the remaining capacity of the DC power supply is greater than the first threshold, the AC-DC converter is stopped ([0057]), and if the remaining capacity of the DC power supply is not greater than the second threshold, the AC-DC converter is started ([0058]; provide power to the DC grid from the AC grid).
Regarding claims 4 and 8, Yoko teaches the DC power supply DC-DC converter increases voltage (up to VC) to be outputted to the DC grid, as the remaining capacity of the DC power supply becomes smaller. (Fig. 3; [0069]; between t3 and t4, during discharging the remaining capacity of the DC power supply becomes smaller and the converter (32) outputs an increasing voltage/power, from P2 to P3 and the voltage increases to VC)
Regarding claim 6, Yoko teaches a storage circuitry which stores time-series predictive generated power of the power generation device and time-series predictive load power of the load ([0006]; operation mode determination information), wherein
in a time period in which the predictive generated power is smaller than the predictive load power, the switchover command generation circuitry reduces the voltage of the DC grid and switches the operation mode of the AC-DC converter from the operation mode 1 to the operation mode 2 (Yoko at [0065]-[0074] and Fig. 3 doesn’t teach reverse flow to AC grid; and Matsui teaches (at [0050]) when generated power is less than load demand, no power to AC grid aka mode 2).
Claim(s) 7 is rejected under 35 U.S.C. 103 as being unpatentable over Yoko et al. (2018/0361859), Knobloch (2023/0084081), and Wang et al. (2015/0002121).
Regarding independent claim 7, Yoko teaches (Fig. 1) a DC power distribution system comprising:
a converter (10) having a forward power flow function of converting power inputted from a power grid (60) to DC power and outputting the DC power to a DC grid (1);
a first sensor which detects generated power of a power generation device (21, 22) connected to the DC grid ([0041]; power generated increases based on bus voltage up to a limit);
a load DC-DC converter (42) which supplies power to a load (52) connected to the DC grid ([0022], [0023]); and
a second sensor which detects power supplied from the DC grid to the load DC-DC converter and the load ([0062]).
Yoko fails to explicitly teach the converter (10) being a bidirectional DC-DC converter, connected to a DC power grid and its two operation modes. Knobloch teaches a similar DC power distribution system (Fig. 1) to that of Yoko. Knobloch teaches a DC power grid (12a) and a bidirectional DC-DC converter (12b) having forward power flow function (from 12a to 10) and a reverse power flow function of converting DC power from the DC grid (10) to DC power and outputting the DC power to the power grid (12a) ([0079]).
Knobloch also teaches a switchover command generation circuitry (that operates the system) which generates a command for switching between two operation modes of the DC-DC converter, wherein
the two operation modes are an operation mode 1 in which the reverse power flow function of the DC-DC converter is enabled, and an operation mode 2 in which the reverse power flow function of the DC-DC converter is disabled (Knobloch teaches the DC-DC converter 12b can operate in reverse power flow mode (mode 1) or not (mode 2)),
in a case where the generated power of the power generation device (i.e. 17 or 18 of Knobloch) detected by the first sensor is smaller than the power supplied to the load DC-DC converter and the load (13 and/or 15), which is detected by the second sensor, the switchover command generation circuitry reduces the voltage of the DC grid and switches the operation mode of the DC-DC converter from the operation mode 1 to the operation mode 2 ([0087]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have Yoko’s converter (10) being a bidirectional DC-DC converter connected to a DC power grid (instead of an AC power grid) and controlling it in the way described in Knobloch, to allow for Yoko’s DC power distribution system to be able to sell power back to the power company and reduce cost and not waste excess power that is generated by Yoko’s system, and since Knobloch teaches the idea of these types of DC power distribution systems comprising either or both of an AC power grid or DC power grid being bidirectionally coupled to a DC grid.
Yoko teaches a DC grid voltage command generation circuitry (13, 23, 33) which generates a DC grid voltage command which is voltage to be outputted to the DC grid by the AC-DC converter (based on monitored bus voltage; [0037], [0040]), wherein
the DC grid voltage command generation circuitry generates the DC grid voltage command that minimizes a sum of losses in power conversion in the AC-DC converter, the load DC-DC converter, and the DC power supply DC-DC converter ([0030]).
Yoko fails to explicitly teach minimizing losses by controlling the converters based on loss characteristics stored in storage circuitry. Wang teaches a similar power distribution system to reduce losses in power converters (Abstract) to that of Yoko. Wang also teaches a storage circuitry which stores loss characteristics in power conversion ([0012]) and generating voltage command values for converters that minimize a sum of power losses in power conversion on the basis of the loss characteristics stored in the storage circuitry ([0033]). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement Wang’s storage circuitry with loss characteristics into Yoko’s invention since Yoko was silent as to how their converters are controlled to minimize power losses, and Wang teaches a known example of how power losses are determined and controlled and minimized, and that is a main goal in Yoko’s invention.
Response to Arguments
Applicant’s arguments, filed March 2, 2026, with respect to the rejection(s) of the claim(s) have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Wang et al. (2015/0002121).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DRU M PARRIES whose telephone number is (571)272-8542. The examiner can normally be reached on Monday -Thursday from 9:00am to 6:00pm. The examiner can also be reached on alternate Fridays.
If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Rexford Barnie, can be reached on 571-272-7492. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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DMP
4/21/2026
/DANIEL KESSIE/Primary Examiner, Art Unit 2836
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