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 with respect to claim(s) 1-8 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
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, 5, 6 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Long et al. (US 20220127011 A1) in view of Knowles et al (US 20160359324 A1), further in view of Wegman et al (US 20100080030 A1).
Regarding claim 1, Long teaches an electrical propulsion system for an aircraft comprising a plurality of batteries and a plurality of electric propulsion systems [see (Abstract; Fig. 2; paras. 0004-0005) a plurality of batteries and a plurality of electric propulsion systems and a plurality of isolated power distribution circuits each coupling a battery of the plurality of batteries to two or more electric propulsion systems - Long teaches an electrically powered aircraft including multiple power sources and propulsion devices]; a plurality of branches [see (Fig. 2, items 205(1)-205(6); paras. 0031-0035) isolated power distribution circuits 205(1)-205(6) each coupling a battery to balanced propulsion systems - Long teaches a plurality of isolated power distribution circuits corresponding to the claimed branch structures]; each branch comprising at least one electrical power source [see (Fig. 2, items 220(1)-220(6); para. 0031) battery 220(1) coupled to primary power distribution circuit 205(1) through contactor 215(1); see also paras. 0033-0035) batteries supplying power through the isolated power distribution circuits - Long teaches the claimed electrical power source]; at least one electric propulsion device [see (Fig. 2, items 105(1)-105(12); paras. 0031-0035) propulsion systems powered through the isolated power distribution circuits - Long teaches the claimed electric propulsion device]; a branch bus, connected to each of the at least one electrical power sources and to each of the at least one propulsion devices of the branch [see (Fig. 2, items 205(1)-205(6); paras. 0031-0035) isolated power distribution circuits 205(1)-205(6) electrically coupling batteries 220(1)-220(6) to propulsion systems 105(1)-105(12) - under the broadest reasonable interpretation, the electrical power distribution paths forming isolated power distribution circuits 205 correspond to the claimed branch bus because they electrically connect the electrical power source and propulsion devices of the branch].
However, Long does not expressly teach a single central bus, connected to the respective branch bus of each branch of the plurality of branches through the DC/DC voltage converter of the branch, wherein each DC/DC voltage converter is configured to galvanically isolate the branch bus from the central bus.
In an analogous art, Knowles teaches an aircraft DC power distribution system including a plurality of dedicated DC buses 18 and a synchronization bus 20 [see (Fig. 1, items 18 and 20; para. 0014) each dedicated DC bus 18 is coupled to synchronization bus 20 through respective synchronization bus line switches 21]; Knowles further teaches that the synchronization bus 20 allows power sharing among selected dedicated DC buses while permitting isolation of other dedicated DC buses [see (Fig. 1, items 18, 20, and 21; paras. 0014-0015) dedicated buses selectively coupled to synchronization bus 20 to allow power sharing and bus isolation; see also paras. 0006-0007 describing a synchronization bus selectively coupleable to multiple dedicated DC buses]. Thus, Knowles teaches a common synchronization bus 20 that is selectively coupled to multiple dedicated DC buses 18 through respective switches 21, thereby providing a shared-bus architecture for power sharing and bus isolation.
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 isolated power distribution circuits of Long with the synchronization-bus architecture of Knowles so that the isolated power distribution circuits selectively share power through a common bus architecture. One of ordinary skill in the art would have been motivated to do so because Knowles teaches that coupling multiple buses through a synchronization bus enables power sharing and fault isolation in an aircraft electrical power system.
However, Long and Knowles do not expressly teach through the DC/DC voltage converter of the branch, wherein each DC/DC voltage converter is configured to galvanically isolate the branch bus from the central bus.
In an analogous art, Wiegman teaches a DC/DC converter providing bidirectional conversion between a first DC power signal on a first DC bus and a second DC power signal on a second DC bus [see (Abstract; para. 0022) DC/DC converter providing bidirectional conversion between a first DC bus and a second DC bus - Wiegman teaches a DC/DC voltage converter disposed between DC bus structures]; Wiegman further teaches an isolated DC/DC converter disposed between DC bus structures [see (Fig. 4, item 86; para. 0014) isolated DC/DC converter 86 located between DC filter 81 and multi-phase inverter 82, wherein DC-DC converter 86 has a high frequency transformer that provides the isolation for the system - Wiegman teaches galvanic isolation provided by a DC/DC converter] Wiegman additionally teaches DC/DC conversion between multiple DC buses in an aircraft electrical power architecture [see (Fig. 1, items 25, 35, and 50; paras. 0006 and 0022) DC/DC converter 50 interconnecting high-voltage DC bus 25 and low-voltage DC bus 35].
Therefore, it would have been further obvious for one of ordinary skill in the art before the effective filing date of the invention to incorporate the isolated DC/DC converter architecture of Wiegman into the combined system of Long and Knowles so that the shared-bus architecture may be implemented using isolated DC/DC conversion while maintaining electrical isolation between interconnected bus structures. One of ordinary skill in the art would have been motivated to do so because Wiegman teaches using isolated DC/DC converters between DC buses to provide controlled power transfer and electrical isolation.
Regarding claim 3, combination of Long, Knowles and Weigman teaches invention set forth above, Long further teaches wherein each of the propulsion devices is connected to the respective branch bus by a disconnection member adapted to passively disconnect the respective propulsion device from the branch bus in the event of overcurrent passing through the disconnection member [see (Fig. 2, item 245; para. 0006) the power distribution circuit further includes a plurality of fuses; see also (para. 0036) fuses can be used in place of contactors 215 or in addition to contactors - Long teaches a plurality of fuses within the power distribution architecture, wherein a fuse is a passive overcurrent-responsive disconnection member configured to isolate faulted circuitry upon occurrence of an overcurrent condition].
Regarding claim 5, combination of Long, Knowles and Weigman teaches invention set forth above, Long further teaches wherein each of the electrical power sources is connected to the respective branch bus by a source switching member of contactor type or of power semiconductor switch type [see (para. 0005) the power distribution circuit further includes a plurality of contactors, each contactor coupled between each respective battery and each respective isolated power distribution circuit; see also (Fig. 2, items 215(1)-215(12), 220(1)-220(12), and 205(1)-205(12); para. 0036) each power distribution circuit 205 is coupled to a respective battery 220 via a respective contactor 215(1)-215(12) - Long teaches a source switching member of contactor type disposed between each battery and the respective isolated power distribution circuit].
Regarding claim 6, combination of Long, Knowles and Weigman teaches invention set forth above, Long further teaches a control circuit configured to implement a fault management method in the event of a fault in the system [see (Fig. 2, item 255; para. 0037) control system 255 can be coupled to controllers 225, 235, contactors 215 and/or batteries 220 to control one or more functions of power distribution system 200; see also (paras. 0041-0042) battery-failure fault management in which control system 255 detects a battery failure, opens contactors 215(1) and 215(7), and increases power supplied by remaining batteries to maintain operation - Long teaches a control circuit configured to implement a fault management method in response to system faults].
Regarding claim 8, combination of Long, Knowles and Weigman teaches invention set forth above, Long further teaches an aircraft comprising the electrical propulsion system as recited in claim 1 [see (Abstract) A power distribution circuit for an electrically powered aircraft; see also (Figs. 1A-1B; para. 0025) electrically powered VTOL aircraft 100 with twelve tilting electronic propulsion systems 105(1)-105(12); see also (Fig. 2; para. 0030) aircraft 100 including power distribution system 200 comprising isolated power distribution circuits, batteries, and propulsion systems - Long teaches an aircraft incorporating the electrical propulsion system].
Allowable Subject Matter
Claims 2, 4 and 7 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.
Regarding claim 2, combination of Long, Knowles and Weigman teaches invention set forth above, combination fails to expressly disclose further comprising a backup electrical power source only connected to the central bus. The prior art of record teaches various power sources, electrical buses, and fault-tolerant aircraft power architectures; however, the prior art of record does not expressly teach or suggest a backup electrical power source having the specific claimed arrangement of being “only connected to the central bus.”
Hence claim 2 will be deemed allowable if written in independent form.
Regarding claim 4, combination of Long, Knowles and Weigman teaches invention set forth above, combination fails to expressly disclose wherein each of respective branch bus of the plurality of branches is connected to the central bus by:- a branch switching member of contactor type or of power semiconductor switch type, and- a diode having a passing direction oriented from the central bus toward the branch bus, the branch switching member and the diode being connected in series between the central bus and the branch bus, in parallel with the DC/DC voltage converter; Although the prior art of record teaches electrical buses, switching devices, and DC/DC converters, the prior art does not expressly teach or suggest the specific claimed circuit topology in which a branch switching member and a diode are connected in series between the central bus and branch bus and arranged in parallel with the DC/DC converter.
Hence claim 4 will be deemed allowable if written in independent form.
Regarding claim 7, combination of Long, Knowles and Weigman teaches invention set forth above, combination fails to expressly disclose comprising steps of: preventing propagation of the fault by means of galvanic isolation implemented by each of the DC/DC voltage converters, - locating the fault and, if necessary, isolating the source or the propulsion device, and where applicable, precharging then restarting the propulsion devices which have stopped; While the prior art of record teaches galvanic isolation, fault detection, and isolation of faulted portions of an aircraft electrical system, the prior art does not expressly teach or suggest the additional recovery operation of “precharging then restarting the propulsion devices which have stopped.
Hence claim 7 will be deemed allowable if written in independent form.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Aqeel H Bukhari whose telephone number is (571)272-4382. The examiner can normally be reached M-F (9am to 5pm).
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/AQEEL H BUKHARI/Examiner, Art Unit 2836
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