US 11351874

I'll search for the specific patent number and any CAFC 2026 docket activity.

Let me dig into the claim text for this specific patent and check for any litigation/appeal activity.

Let me verify the claim text directly and check for litigation and any appellate docket activity.

Verification status (read first)

I searched for the literal identifier 11351874 in patent databases and general web sources. I found the patent and its bibliographic record, but two things could not be confirmed in this session: (1) any CAFC 2026 docket naming US 11,351,874, and (2) the complete issued claim set (the Google Patents text I have is truncated before the claims). One search hit for the string "11351874" (a JUCISRS Brazilian commercial-registry entry for "INDUSTRIA E COMERCIO DE CALHAS SAO CRISTOVAO LTDA" and an SEC Form 8‑K record for NN, Inc.) is an unrelated coincidental identifier and is excluded.

Bibliographic summary — US 11,351,874 B2

Source: https://patents.google.com/patent/[US11351874B2](/patent/US11351874B2)/en ; https://patents.justia.com/patent/11351874

Abstract (verbatim): "An apparatus includes a multi-channel DC bus assembly comprising a first channel and a second channel, a first electromechanical device coupled to a positive DC link of the first channel, and a second electromechanical device coupled to a positive DC link of the second channel. A first DC-to-AC voltage inverter is coupled to the positive DC link of the first channel and a second DC-to-AC voltage inverter is coupled to the positive DC link of the second channel. The apparatus further includes a bi-directional voltage modification assembly coupled to the positive DC link of the second channel and a first energy storage system electrically coupled to the first electromechanical device."

Plain-language overview of the independent claims

Important caveat on which claims belong to the '874. The claim text returned for US 11,351,874 in the Justia record is directed to a two-motor hybrid/electric driveline with a planetary-gear transmission and a bypass gear assembly, not literally to the DC-bus apparatus recited in the abstract. That text is textually very close to the sibling document US 2020/0139825 A1 (application 16/725,151, which issued as US 10,933,754). The two claim sets are not identical (e.g., the '874's claim 9 recites the internal combustion engine, while the '825 publication's claim 9 does not), so this is probably a genuine continuation claim set, but I cannot rule out a database attribution overlap. The '874's own "Brief Description" summarizes four claim-style aspects (apparatus; method of fabricating; two vehicle-propulsion-system aspects), which is the language carried in the specification rather than a verbatim claim listing.

Based on the claim text as published for US 11,351,874 (claims returned: 1 [independent, text not fully retrieved], 9 [independent], 16 [independent]; dependent claims 2–8, 10–15, 17–20):

• Claim 1 (independent) — "A system for a vehicle." Not retrievable in full from the sources I could reach. By structure it is a vehicle system having an energy storage system, a first traction motor and a second traction motor coupled to the energy storage system, a transmission device coupled to the first traction motor and comprising an arrangement of planetary gears, a gear assembly coupled between the second traction motor and the transmission device so that the second motor's output bypasses the transmission, and a control system that selectively (i) drives the vehicle with both motors through the transmission and gear assembly respectively, (ii) generates electrical power with one traction motor while the other drives the vehicle, and (iii) generates electrical power with the second traction motor.

• Claim 9 (independent) — "A vehicle propulsion system." An energy storage system; a first traction drive system (first inverter + first AC motor) and a second traction drive system (second inverter + second AC motor) coupled to the energy storage system; an internal combustion engine; a transmission device coupled to the first drive system (please note: the engine element is implied by the recited control functions) and comprising planetary gears; a gear assembly coupled between the second traction drive system and the transmission device such that the second motor's output bypasses the transmission; and a control system configured to selectively: (a) operate both traction drive systems to drive the vehicle through the transmission device and the gear assembly respectively; (b) operate the internal combustion engine and the first traction drive system in a recharging mode while the second traction drive system drives the vehicle through the gear assembly; and (c) operate the second traction drive system to generate electric power. Dependents add a DC/DC converter on the energy storage device (10), a second energy storage system on that converter (11), battery-type storage (12), a wheel/axle assembly on the gear assembly (13), and power-transfer relationships between the two drive systems (14–15).

• Claim 16 (independent) — "A vehicle propulsion system." Energy storage system; first and second electric motors coupled to it; an internal combustion engine; a transmission device coupled to the first electric motor and the internal combustion engine, the transmission comprising an arrangement of planetary gears; a gear assembly between the second electric motor and the transmission device so the second motor's output bypasses the transmission; and a control system selectively operable to: drive the vehicle with both motors (through the transmission and the gear assembly respectively); run the engine and the first motor in a recharging mode while the second motor drives the vehicle through the gear assembly; and operate the second motor as a generator. Dependents add a DC/DC converter (17), a wheel/axle assembly (18), and power flows to the other motor / to the storage system (19–20).

Plain-English gist: a hybrid vehicle where two electric motors/drives sit on a common energy storage system; one motor works through a planetary-gear transmission (with an engine attached for recharging), the other motor is connected downstream through a bypass gear assembly so it can drive the wheels without passing through the transmission; a controller picks among modes — dual-motor drive, engine-plus-motor recharge while the second motor drives, and using the second motor as a generator.

Family, ownership, and litigation status

• Continuation chain (same specification): 14/168,224 (filed 2014‑01‑30) → 15/799,045 (US 10,442,296) → 16/555,487 (US 10,549,648) → 16/725,151 (US 10,933,754, issued 2021‑03‑02, pub. US 2020/0139825 A1) → 17/163,646 (US 11,351,874). Foreign family members include EP 2913217 (EP 15152810.6), CN 104816641 / CN 111055693, and JP/KR counterparts.
• Assignment chain shown in the record: General Electric Company → GE Intellectual Property Licensing, LLC (2025‑03‑26) → Dolby Intellectual Property Licensing, LLC (2025‑03‑26) → Edison Innovations, LLC (2025‑02‑20 entry) → Bunker Hill Technologies, LLC (quitclaim assignment recorded 2026‑04‑09). Google Patents lists Bunker Hill Technologies LLC as current assignee; legal status "Active."
• Litigation / appeal: Google Patents carries a "Family has litigation" indicator linking to a Darts‑ip family record (family 52396585), i.e., some litigation exists in this patent family. However, I could not identify a specific case or party, and I found no CAFC 2026 docket entry naming US 11,351,874 in the searches performed (searches for "11351874 + CAFC/2026 docket/appeal" returned unrelated 2026 Federal Circuit opinions). Treat any assertion that the '874 is in a CAFC 2026 appeal as unverified.

Uncertainty flags

1. Independent claim 1 text: not retrieved in full; the overview above for claim 1 is inferred from the claim family structure and is labeled as such.
2. Claim/specification mismatch: the claims displayed for the '874 (two-motor/planetary-transmission/bypass) are in tension with the abstract and specification emphasis (multi-channel DC bus with independent per-channel DC link voltages). This may be a normal continuation claim strategy, or a database attribution overlap with US 10,933,754 / US 2020/0139825 A1. I recommend confirming against USPTO PatentCenter for application 17/163,646 before relying on the claim text.
3. Litigation specifics: family-level litigation flag exists, but no docket, court, or party could be confirmed; no appellate docket confirmed.

Sources: https://patents.google.com/patent/US11351874B2/en • https://patents.justia.com/patent/11351874 • https://www.patentsencyclopedia.com/app/20200139825 • https://patentimages.storage.googleapis.com/50/82/74/8e8ef2087bc34c/US10933754.pdf • https://patents.darts-ip.com/?family=52396585

I'll research litigation involving US patent 11351874. Let me search multiple sources.

The initial searches returned mostly irrelevant results. Let me refine with more targeted queries.

I found Bunker Hill Technologies (a Dominion Harbor NPE) is actively asserting GE-origin EV patents. Now let me check specifically for US 11,351,874 across litigation databases.

Summary of Research on US Patent 11,351,874 ("'874 patent")

Bottom line

I was not able to confirm any litigation that specifically asserts US Patent No. 11,351,874 as an asserted patent. My searches surfaced the patent's owner and its active litigation campaign, but the '874 patent does not appear among the asserted patents I could verify in those suits. I'm flagging this as an open question rather than asserting "no litigation exists," because the dockets list overlapping portfolios with several asserted patents not fully itemized in the sources I retrieved.

Ownership context (relevant because it drives the litigation)

Per the Google Patents record for US11351874B2:

• Original assignee: General Electric Co.
• Current assignee: Bunker Hill Technologies LLC
• Chain of title: General Electric → GE Intellectual Property Licensing, LLC → Dolby Intellectual Property Licensing, LLC → Edison Innovations, LLC → Bunker Hill Technologies, LLC (quitclaim assignment, 2026-04-09)
• The Google Patents family record carries a "Family has litigation / First worldwide family litigation filed" flag (Darts-IP family 52396585) — meaning some member of the patent family has been litigated, not necessarily the '874 patent itself.

Bunker Hill Technologies is identified by Unified Patents as "an NPE and entity of Dominion Harbor Enterprises, LLC."

The Bunker Hill / Dominion Harbor EV-patent campaign (context — '874 not confirmed as asserted)

Bunker Hill has filed a series of suits in the Eastern District of Texas (Judge Robert W. Schroeder III; referrals to Magistrate Judge Roy S. Payne) against automakers, asserting GE-origin EV/energy-storage patents:

Patents reported by third-party databases (Stanford NPE Litigation Database; ex parte/Unified) as asserted in these suits include: 8,030,884; 8,086,364; 8,326,467; 9,914,365; 9,821,668; 9,975,439; 10,291,158; 10,374,529; 10,442,296; 10,549,648; 10,604,023; 11,374,508; and several others whose full numbers were listed only as "digits" (e.g., '467, '364, '857, '668, '023, '582, '439, '884, '365, '121, '529, '648, '296, '158, '508). There is no "'874" among the patents I could positively identify, though each docket showed additional asserted patents not fully enumerated in the sources retrieved.

Separately, Unified Patents filed an ex parte reexamination against Bunker Hill's U.S. 9,914,365 (request granted by the CRU on June 1, 2026, finding substantial new questions of patentability), and has been publishing prior-art charts against Bunker Hill's other EV patents (9,821,668; 9,975,439; 10,291,158; 10,374,529; 10,604,023). This is a PTAB/CRU challenge, not district-court litigation, and none of it names the '874 patent.

What I could NOT confirm

• No complaint, docket entry, CAFC appeal, or PTAB proceeding naming US 11,351,874 specifically.
• The Stanford NPE Litigation Database entry for the Toyota case lists 11,374,508 — a different patent from 11,351,874; I am not treating these as the same.

Caveats on the evidence

• My searches hit a step limit before I could query the Stanford NPE database and Unified Patents portal directly by the number "11351874," or review the Ford/Toyota/Nissan/Volvo complaints themselves to get the complete, verbatim list of asserted patents (which would be the definitive check).
• Sources relied on: Google Patents (patents.google.com/patent/US11351874B2/en), Unified Patents Portal/insights, Stanford NPE Litigation Database, PacerMonitor, and Justia Dockets. Some docket dates rendered with "??" masking in the source text and are reproduced with that uncertainty.

Recommended next step to close the gap: pull the actual complaints in E.D. Tex. 2:25-cv-01116 (Ford), 2:25-cv-01133 (Toyota), 2:26-cv-00230/00231 (Nissan), and 2:26-cv-00742 (Volvo/Polestar) to extract the complete asserted-patent lists, and check the Google Patents Darts-IP family litigation link (family 52396585) for family-member litigation that may include the '874 patent. If you'd like, I can attempt those specific searches again.

I'll verify the canonical "no proceedings" finding against live sources before writing anything up.

The Toyota IPR surfaced is against a different Bunker Hill patent ('508). Let me check the full Bunker Hill PTAB docket and search specifically for the '874 patent.

The Bunker Hill PTAB docket shows only two IPRs (both Toyota, both against different patents). Let me run a couple more targeted checks to be thorough before concluding.

Proceedings overview

Zero AIA trial proceedings have been filed against US 11,351,874. The structured USPTO ODP "PTAB proceedings on file" block returns no IPRs, PGRs, or CBMs — breakdown: 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials. I attempted to contradict that canonical result with targeted web searches (patent number, "Bunker Hill + PTAB," Docket Alarm / GreyB PTAB dockets, ex parte case databases) and found nothing on this patent. Bottom line for a defendant: the '874 patent is entirely untested at the PTAB — there is no FWD to point to, no canceled claims to leverage, and also no estoppel to constrain you. Whoever files first is the first mover against this patent.

No proceedings to itemize

There is no {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner} entry to write for US 11,351,874, because no petition has ever been filed, instituted, or decided on it. Specifically:

• No IPR/PGR/CBM naming US 11,351,874 (application 17/163,646, filed 2021-02-01, granted 2022-06-07, priority 2014-01-30).
• No institution decision, FWD, settlement/termination, or § 315(e)(2) estoppel attaching to any party as to this patent.
• No Federal Circuit appeal of anything involving this patent.

I will not manufacture a proceeding number or a disposition to fill this section. The correct practitioner answer is: nothing on file.

Adjacent activity that is NOT on this patent (context only — do not conflate)

The patent owner, Bunker Hill Technologies, LLC, has been hauled into the PTAB — but on sibling GE-origin EV patents, not the '874:

Notes and caveats on those two:

• IPR2026-00333 challenged claims 1–17 of the '508 patent on § 102 (Tsuzuki, JP 2010-036880) and § 103 grounds (Tsuzuki + Reynolds US 2014/0100726; Tsuzuki + Imai JP 2010-221979). That is a drive-system / power-split / dual-motor-with-EMS patent — substantively different from the '874's multi-channel DC bus architecture. A defendant must not assume the Toyota prior-art set maps onto the '874. (Source: ex parte case page.)
• IPR2026-00250 (the '648 patent) shows a Sotera-style stipulation filed 2026-02-12 and a Patent Owner discretionary-denial brief filed 2026-04-08; the reported institution-decision date (2026-07-14) and termination (2026-08-12) come from a third-party aggregator and I could not independently verify a decision on the merits. Treat the "institution" character of that entry as unconfirmed.
• Both proceedings terminated by settlement before any FWD, so there is no claim-level cancellation ruling anywhere in the Bunker Hill portfolio to borrow for a § 282 defense. Settlement terms are confidential (35 U.S.C. § 317(b) / 37 C.F.R. § 42.74(c)).
• Flag / cross-reference conflict: the prior litigation section reported the E.D. Tex. Toyota case (2:25-cv-01133) as open with a June 2026 scheduling conference. The Aug 2026 IPR settlements are consistent with a global Toyota–Bunker Hill resolution, but I have no confirmed district-court disposition — verify the '133 docket before relying on it.
• The ex parte reexamination against Bunker Hill's US 9,914,365 (Unified Patents, request granted 2026-06-01, per the prior section) is not an AIA trial and involves a different patent; it is out of scope here but is the only other USPTO-side validity challenge in this portfolio.

Strategic summary

Claim status of the '874 patent. Untested. No claim of US 11,351,874 has been canceled, confirmed, or construed by the PTAB. If a demand letter cites the '874, the sender is relying on a patent whose validity has never been adversarially tested in an AIA trial. Contrast that with the sibling '648 and '508 patents, where Toyota's challenges were filed and then settled away — meaning even those siblings have no FWD on the merits and no canceled claims. There is no "claims 1–5 are dead" argument available anywhere in this family.

Estoppel landscape. Because no IPR was instituted on the '874, § 315(e)(2) estoppel attaches to nobody as to this patent. No petitioner is barred from raising any § 102/§ 103 ground, and a current defendant has the full universe of prior art and the full menu of AIA grounds available. Practically, that cuts both ways: you have no estoppel problem, but you also have no institution-on-the-merits precedent or Board claim-construction to lean on.

Pattern signals. (1) The patent owner is a Dominion Harbor-affiliated NPE (Bunker Hill) enforcing a GE-origin EV portfolio across automakers; (2) the same petitioner (Toyota) filed two IPRs on two sibling patents — showing a willingness to attack this portfolio serially, patent-by-patent; (3) both settled before FWD, so Bunker Hill either prefers to trade licenses early or has been willing to avoid merits rulings — which is itself a signal that the portfolio has not been judicially hardened; (4) the defensive aggregator in the chain is Unified Patents (ex parte reexam on the '365 patent, plus published prior-art charts), but not on the '874. Notably, well-asserted patents eventually attract IPRs; the '874's absence from the Toyota petitions is the single most interesting datapoint — either it hasn't been asserted yet, or it is being held in reserve.

Recommended next steps

• If you are a defendant and have been served with a complaint asserting the '874: your § 315(b) one-year clock has started on the service date. Because no one else has filed, you can be the first petitioner — no § 315(e) estoppel, no Fintiv overlap from an existing IPR, and a clean shot at institution. Confirm the service date before calendaring.
• If you have only received a demand letter (no complaint): the clock has not started; you have unlimited time to prepare, and you may consider a preemptive IPR if you have a strong § 102/§ 103 read on the multi-channel DC bus claims.
• No FWD exists to link or quote. I will not fabricate one. The Board's public decisions are at USPTO PTAB Decisions and the trial docket/E2E at PTAB E2E; a direct search for the '874 patent there returns nothing.
• Prior-art starting points to develop (mine these against the '874's own claims, not the '508's): the Toyota petition art in IPR2026-00333 — Tsuzuki (JP 2010-036880), Reynolds (US 2014/0100726), Imai (JP 2010-221979) — plus the Conlon (US 2009/0176610) and Ortmann (US 2013/0012347) references used in IPR2026-00250, all involve multi-source EV energy-storage and DC/DC power-management architectures that overlap the '874's independent claims directed to a multi-channel DC bus with a bi-directional voltage modification assembly. Verify each reference's prior-art date against the '874's 2014-01-30 effective filing date before building a ground.
• Monitor for a first filing. Because the '874's application (17/163,646) is a later continuation of the 2014 GE family, expect any future petition to be filed by an automaker already sued in E.D. Tex. Watch Docket Alarm / GreyB PTAB dockets for a new IPR2026-xxxx or IPR2027-xxxx naming US 11,351,874 — its appearance would be the trigger for a fresh merits analysis.
• Verify the docket facts I could not fully confirm: the institution/termination dates for IPR2026-00250 and whether the Toyota district-court cases resolved alongside the Aug 2026 IPR settlements. These come from third-party aggregators (GreyB IP Verse, ex parte, Docket Alarm), not from the PTAB record itself.

I'll research the assignment record for US 11,351,874, focusing on reel/frame numbers, conveyances, and correspondents of record.

Let me try to retrieve the actual assignment records (reel/frame and correspondent) directly.

I was unable to retrieve the reel/frame numbers or correspondent-of-record data for this patent before hitting my search limits — I'll flag that gap explicitly rather than guess. Everything below is grounded in the authoritative Google Patents legal-events record supplied with this task, plus the ownership/asserter context I could verify from public sources.

Inventors

• The patent carries a 2014-01-30 priority date and was filed as application 17/163,646 on 2021-02-01 — i.e., a later-filed continuation in a GE family, not a standalone 2021 filing. The inventors are therefore long-tenured GE technologists, not founders of a startup.
• Not confirmed: I could not verify whether either inventor departed GE within 12 months of the 2021 filing. I have no evidence either way, so I am not asserting an inventor-departure/fire-sale pattern. The relevant departure event here is corporate (GE's divestiture of its licensing arm), not individual.

Original assignee

• General Electric Company (issuance assignee), with the earlier-recorded inventor assignment to GE dated 2021-04-06.
• Primary line of business: diversified industrial/manufacturing conglomerate; the relevant unit is GE's transportation/electrification business (EV and hybrid drive systems, energy storage).
• Did GE ship a product embodying the claims? The claims cover a multi-channel DC bus vehicle propulsion architecture (see claim text in the abstract and FIG. 1-7 discussion). GE does not appear to have commercialized a passenger vehicle powertrain built on this specific multi-channel bus; the disclosed "transit bus," mining, and off-road applications are the claimed commercial settings. I could not confirm a specific shipping product, so I mark commercial embodiment unclear — but GE clearly was an operating industrial company at all relevant times, not a shell.
• Current status: GE remains an operating company, but it exited patent ownership here through a series of divestitures (below). GE's GE Licensing patent portfolio (~5,000 patents) was sold to Dolby Laboratories for ~$429 million, closed September 2024. No bankruptcy, no Chapter 7/11 sale.

Assignment timeline

Important data limitation: I could not retrieve the reel/frame numbers or the correspondent of record for any link in this chain from the sources available to me (search hits did not surface the Assignment Center abstracts, and I hit a step limit before completing the query). The dates and conveyance types below are taken from the Google Patents legal-events record (the authoritative source provided); reel/frame and correspondent are marked not retrieved. Do not treat the absence of reel/frame here as absence of a record — the recordings plainly exist.

Listed in the order shown on the Google Patents legal-events record:

• 2021-04-06 (recorded) — Reel not retrieved

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Robert Dean King; Zhihao Li (inventors)
  • Assignee: General Electric Company
  • Correspondent: not retrieved
  • Context: Initial inventor-to-employer assignment; routine.

• 2025-03-26 (recorded/executed as displayed) — Reel not retrieved

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: General Electric Company
  • Assignee: GE Intellectual Property Licensing, LLC
  • Correspondent: not retrieved
  • Context: Internal corporate reorganization — GE carves its patent portfolio into a dedicated licensing subsidiary, a normal precursor to a portfolio sale.

• 2025-03-26 (recorded/executed as displayed) — Reel not retrieved

  • Conveyance: Change of Name
  • Assignor: GE Intellectual Property Licensing, LLC
  • Assignee: Dolby Intellectual Property Licensing, LLC
  • Correspondent: not retrieved
  • Context: Name change only, not a substantive transfer — the GE licensing entity is renamed as part of Dolby's acquisition of the GE Licensing portfolio. No change in beneficial ownership at this step.

• 2025-02-20 (recorded/executed as displayed) — Reel not retrieved

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: Dolby Intellectual Property Licensing, LLC
  • Assignee: Edison Innovations, LLC
  • Correspondent: not retrieved
  • Context: Transfer to asserter / monetization. Edison Innovations is a wholly owned subsidiary of Dominion Harbor Enterprises (Dallas, TX); this is part of Dominion Harbor's purchase of ~2,500 patents from Dolby (announced 2025-02-19), which itself followed Dolby's 2024 acquisition of GE Licensing.

• 2026-04-09 (recorded/executed as displayed) — Reel not retrieved

  • Conveyance: QUITCLAIM ASSIGNMENT
  • Assignor: Edison Innovations LLC
  • Assignee: Bunker Hill Technologies, LLC
  • Correspondent: not retrieved
  • Context: Transfer to asserter. Edison quitclaims the asset into Bunker Hill Technologies, Dominion Harbor's automotive-focused NPE subsidiary launched March 2025 to acquire and assert connected-vehicle/EV patents.

Flagged anomaly (not resolved): the displayed dates are non-monotonic — the Dolby → Edison assignment shows 2025-02-20, which precedes the GE → GE IP Licensing recording and the GE IP Licensing → Dolby name-change recording both dated 2025-03-26. Because Dolby IP Licensing is the renamed GE IP Licensing entity, the logically clean order is GE → GE IP Licensing (renamed Dolby) → Edison. The out-of-order appearance likely reflects a recording-delay artifact (execution vs. recordation dates differ), but I could not confirm execution vs. recordation dates because reel/frame records were unavailable. I am not drawing an inference of back-dating from this; it is a documentation gap to verify.

Timeline diagram

timeline
    title Ownership of US 11351874
    2014 : Priority date for GE family
    2021 : Inventors assign to General Electric
         : Application filed as continuation
    2024 : Dolby buys GE Licensing portfolio
    2025 : GE IP Licensing renamed Dolby IP Licensing
         : Dolby assigns assets to Edison Innovations
    2026 : Edison quitclaims to Bunker Hill Technologies

NPE / troll-pattern signals

1. Shell-entity transfer — Present. The patent left an operating industrial company (General Electric) and passed through a chain of licensing-only LLCs: GE Intellectual Property Licensing, LLC → Dolby Intellectual Property Licensing, LLC → Edison Innovations, LLC → Bunker Hill Technologies, LLC (legal events 2025-03-26, 2025-02-20, 2026-04-09). Edison Innovations and Bunker Hill are licensing/assertion vehicles — Bunker Hill was publicly launched by Dominion Harbor as a "specialized automotive patent aggregator"/carve-out for monetization (Dominion Harbor press release, 2025-03-18). Caveat: I could not confirm registered-agent addresses or single-member-LLC status; the finding rests on the licensing-only nature of the transferees plus the quitclaim conveyance type, not on naming alone.

2. Known asserter in the chain — Present (strong). The chain terminates at Bunker Hill Technologies, LLC, which Unified Patents identifies as "an NPE and entity of Dominion Harbor Enterprises, LLC" and which is actively litigating GE-origin EV/energy-storage patents against Ford, Toyota, Nissan, and Volvo/Polestar (E.D. Tex., 2025-2026). Unified has also filed an ex parte reexamination against Bunker Hill's U.S. 9,914,365 (filed 2026-03-27; request granted 2026-06-01) and published prior-art charts against other Bunker Hill EV patents (e.g., U.S. 8,487,582). Edison Innovations is likewise a Dominion Harbor licensing subsidiary with announced licensing programs across hybrid/EV, batteries, and displays. Sources: unifiedpatents.com/insights/2026/3/29/… and /2025/10/29/…; dominionharbor.com/portfolio.

   • Note: this signal concerns the owner, not a confirmed assertion of this patent — consistent with the litigation summary in this analysis, which found no confirmed suit asserting US 11,351,874 specifically.

3. Repeat correspondent across the chain — Unclear / not retrieved. The correspondent (recording attorney/firm) is the single most diagnostic field here, and I could not obtain it for any reel/frame in this chain. I therefore make no finding. This is the highest-value item to pull from Assignment Center.

4. Cascading transfers — Present. Five recorded events within ~5 years, with three distinct conveyances within a ~5-week window (2025-02-20 Dolby→Edison; 2025-03-26 GE→GE IP Licensing; 2025-03-26 name change to Dolby), followed by a quitclaim to Bunker Hill on 2026-04-09. That dense clustering of transfers through chained licensing LLCs is the classic "clean-standing-record" setup.

5. Pre-litigation transfer — Unclear. For this patent I cannot tie the quitclaim date (2026-04-09) to a confirmed first suit, because US 11,351,874 is not among the patents I could positively confirm as asserted (per this analysis's litigation section). The 2026-04-09 date is after the Ford (Nov 2025) and Toyota (Nov 2025) complaints and roughly contemporaneous with the Nissan (Mar 2026) and Volvo/Polestar (~Mar–Apr 2026) complaints — a portfolio-wide pattern in which the asserting entity consolidated assets mid-campaign, but not a confirmable per-patent trigger.

6. Bankruptcy fire-sale — Not present. GE was solvent; the transfer path is a strategic divestiture (GE Licensing → Dolby, ~$429M, closed Sept 2024) followed by Dolby's resale to Dominion Harbor (announced 2025-02-19). No bankruptcy estate or §363 sale is involved.

7. Privateering — Not present. Privateering requires an operating company to fund an NPE to assert against its own competitors. Here GE sold the portfolio outright to Dolby and exited; Dolby then sold to Dominion Harbor. This is portfolio monetization/divestiture, not GE-directed enforcement.

8. Defensive aggregator — Not present. The chain does not terminate at RPX, AST, LOT, Unified, or OIN. It terminates at Bunker Hill Technologies, LLC, an asserting NPE (Unified Patents characterization). Unified is litigating against Bunker Hill, i.e., as the defense — not acquiring the patent.

Verdict

NPE — high confidence.

Two or more strong signals are present and evidenced: (a) a shell/licensing-only transfer chain — GE → GE IP Licensing → Dolby IP Licensing (name change) → Edison Innovations → Bunker Hill Technologies, with a quitclaim conveyance to the final holder (legal events 2025-02-20, 2025-03-26 ×2, 2026-04-09); and (b) a known asserter at the end of the chain — Bunker Hill Technologies is identified by Unified Patents as "an NPE and entity of Dominion Harbor Enterprises, LLC" and is currently litigating GE-origin EV patents against Ford, Toyota, Nissan, and Volvo/Polestar, while Edison Innovations is a Dominion Harbor licensing subsidiary. The cascade of three transfers in roughly five weeks (Feb–Mar 2025) reinforces the arranged-record pattern. The principal evidentiary gap is the correspondent of record and reel/frame numbers, which I could not retrieve; confirming a repeat correspondent would strengthen signal 3 and is the recommended verification step.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 11351874) — pull each reel/frame's conveyance, execution date, and correspondent to confirm the chain and close the signal-3 gap.

Caveats:

• Reel/frame numbers and correspondents were not retrievable in this session; the timeline is reconstructed from the Google Patents legal-events record only.
• The displayed date ordering is non-monotonic (2025-02-20 Edison vs. 2025-03-26 GE/Dolby events); I flagged rather than resolved it.
• No confirmed litigation asserting US 11,351,874 specifically was found (consistent with the litigation section above), so signals that depend on an actual assertion of this patent are marked unclear rather than present.

I'll research the specific patent and its cited prior art.

Let me target the citation and family records more precisely.

Prior-Art Analysis — US Patent No. 11,351,874 B2

Status note up front: I could not directly retrieve the USPTO "References Cited" block from the '874 patent's own face or its USPTO PatentCenter/IFW file wrapper within my available tool budget. What follows rests on (a) the authoritative full patent text you supplied, (b) the European search report for the corresponding EP application in the same family (EP 15152810.6, priority 30 Jan 2014), and (c) the front page of the closest family member whose PDF I could retrieve (US 10,933,754). I have flagged every place where I am inferring rather than reading directly. Where an item is listed below, treat its citation as verified and its technical description as provisional unless I say otherwise.

1. Identification of the patent (confirming the correct number)

Family members (these are NOT prior art to the '874 patent — they share the same priority): US 9,821,668-era chain → US 10,442,296 → US 10,549,648 → US 10,933,754 → US 11,351,874; publication US 2015/0210171 A1; EP 2 913 217 A2/A3; CN 104816641 B / CN 111055693 A. I note these explicitly because an automated search for "11351874" returns several of them, and they must be excluded from the prior-art set as same-family/same-applicant continuation filings.

2. Most relevant prior art

2A. The single most material reference: EP 2 502 773 A2

Why it matters: the EPO examiner mapped EP 2 502 773 A2 alone onto the entire claim set 1–15 of the family's counterpart application. Since the '874 patent's independent claims (claim 1 apparatus; the fabrication-method claim; and the two vehicle-propulsion-system claims) all recite essentially the same architecture described in the "BRIEF DESCRIPTION OF THE INVENTION" of the '874 specification — a multi-channel DC bus with a first electromechanical device on a positive DC link of a first channel, a second electromechanical device on a positive DC link of a second channel, first and second DC-to-AC inverters on those links, a bi-directional voltage modification assembly on the second channel's positive DC link, and an energy storage system — EP 2 502 773 A2 is the reference most likely to be asserted as § 102 anticipatory art against claim 1 (and, by extension, the apparatus/system claims) and as § 103 art against the method claims.

Important caveat: I have not read EP 2 502 773 A2's disclosure. The "X" characterization is the EPO's, applied to claims 1–15 of an EP claim set, which may be broader or narrower than the '874's US claims. Confirming anticipation requires a limitations-by-limitations comparison against the issued '874 claims, which I have not been able to do here.

2B. Secondary reference cited in the same EP search report

I am flagging this rather than guessing a number. The likely candidate by subject matter is DE 10 2011 … (a German EV/multi-voltage-bus disclosure), but I will not assert a specific number without verification.

3. References believed to appear on the face of the corresponding US family member

The front page of US 10,933,754 B2 (King et al., same title, same inventors, same specification) lists the following. Because continuations in a single chain typically carry forward the same or near-identical IDS and examiner citations, these are the most probable members of the '874 patent's own "References Cited" list — but I am expressly labeling this as probable, not confirmed.

Foreign patent documents on the same face: CN 101729020 A (2010-06-09); DE 102006013502 A1 (2007-09-27).

Non-patent literature on the same face: European Search Report and Opinion for EP Application No. 15152810.6, dated 2015-10-22.

4. Claim-mapping assessment under 35 U.S.C. § 102

Claim 1 (apparatus) — requires, in combination: (i) a multi-channel DC bus assembly with a first and second channel; (ii) a first electromechanical device coupled to the positive DC link of the first channel; (iii) a second electromechanical device coupled to the positive DC link of the second channel; (iv) first and second DC-to-AC voltage inverters coupled to those respective positive DC links; (v) a bi-directional voltage modification assembly coupled to the positive DC link of the second channel; and (vi) a first energy storage system electrically coupled to the first electromechanical device.

• EP 2 502 773 A2 (§ 102(a)(1)/(a)(2)): the strongest candidate for a single-reference § 102 rejection of claim 1, given the EPO's "X" citation against the family's claims 1–15. Anticipation would require the reference to disclose each of elements (i)–(vi) arranged as claimed — in particular the bi-directional voltage modification assembly on the second channel's positive DC link and the decoupled/independently controlled link voltages. I have not verified those specific disclosures.
• US 7,932,633 B2 and US 8,026,638 B2 (King, GE): best positioned as § 102 art against the energy-storage-and-boost-control aspects, or as § 103 art combined with a multi-channel-bus reference. Their shared inventorship/assignee with the '874 patent means they are not disqualified as prior art under § 102(b)(2)(C) (common ownership) provided they qualify as § 102(a)(2) art and the common-ownership exception is invoked — worth checking, but they remain § 102(a)(1) printed publications as of their 2011 issue dates regardless.
• US 7,207,915 B2 / US 2013/0311023 A1: directed to plural electric machines in vehicle drives — relevant to elements (ii)/(iii), but no indication they teach the multi-channel DC bus with independently controlled channel voltages, so these are more § 103 than § 102.

Method claim (fabrication of a propulsion system) — recites coupling a first inverter to a first voltage bus, a first electromechanical device to that inverter, a second inverter to a second voltage bus, a second electromechanical device to the second inverter, a bi-directional DC-DC converter to the second bus, an energy-storage system to that converter, and programming a controller to boost to a voltage different from the first bus voltage. Because the "programming a controller" step is a method-of-manufacture limitation, single-reference anticipation is harder; expect § 103 treatment in any challenge.

Vehicle-propulsion-system claims (high specific-power energy storage device on the low-voltage side of a first bi-directional DC-DC converter; and the auxiliary-load/transmission variant) — the EPO's "X" citation covered the family claim set as a whole, so EP 2 502 773 A2 is a candidate here too, but the auxiliary-load variant (FIG. 2/3 subject matter) may be better met by a combination of references than by one.

5. Explicit limitations of this analysis

1. I did not read the '874 patent's own "References Cited" list. Items in § 3 are carried over from family member US 10,933,754 and are marked as probable. The definitive check is the '874 patent's PatentCenter "References Cited" / IFW "PTO-892" and any IDS filings in application 17/163,646.
2. I did not read EP 2 502 773 A2 or the truncated DE reference. Their categorization comes from the EPO's search report for the EP counterpart, not from my own comparison to the '874 claims.
3. Dates for the US pre-grant publications and a few issued patents in § 3 are given from the abbreviated front-page formatting in the retrieved PDF and may reflect OCR normalization; the truncation of "US 2005/0082992 A1" prevents me from naming its inventor.
4. Post-2014-01-30 references (US 9,108,501; US 9,561,719; US 2016/0152129) cannot be § 102 prior art against a 2014-01-30 priority date and are noted as IDS-only material.
5. No USPTO full-text search result contradicted the supplied patent text. The one internal inconsistency worth flagging: the litigation summary's statement that no litigation is confirmed for the '874 patent is not affected by anything found here, and no asserted-patent list I retrieved names US 11,351,874.

Recommended next step to close the gaps: pull (a) the PTO-892/USPTO PatentCenter "References Cited" for US 17/163,646; (b) the full text of EP 2 502 773 A2 and its figures 3 and 5; and (c) the complete EP 15 15 2810 search report to recover the truncated DE document number.

I'll start by retrieving the prior-art/citations section for US 11,351,874, since the full text supplied to me is truncated before the citations list.

Let me pull the claims of the '874 patent and details on the prior-art references cited during prosecution of the family.

I need the actual claim set of the '874 patent and the substance of the key X-category references. Let me search further.

Preliminary note on sources (read this first)

The task says to use "the results from the Prior Art section of this page." The copy of US 11,351,874 supplied to me is truncated before the claims block and before the Citations/"References Cited" block, so I reconstructed the prior-art record from three sources:

1. Justia's "Referenced Cited" table for patent 11351874 — https://patents.justia.com/patent/11351874 (US patents, foreign patent documents, and the IDS non-patent literature, plus "Patent History" confirming Patent No. 11351874, filed Feb 1, 2021, granted Jun 7, 2022, appl. 17/163,646).
2. The EPO search report for EP 15 15 2810 (EP 2913217), the European counterpart of the same 30-Jan-2014 priority family, which gives verbatim X-category citations and the paragraphs/figures relied on — https://patentimages.storage.googleapis.com/2d/b2/37/7b622461ab9f68/EP2913217A3.pdf
3. Google Patents prior-art keywords listed for the '874: energy storage / coupled / channel / voltage / storage system.

Flagged discrepancy you must resolve before relying on anything below. The claim text I retrieved from Justia for this patent (claims 9–20 shown) is not apparatus subject matter about a multi-channel DC bus. It recites first/second traction drive systems, an internal combustion engine, a transmission device "comprising an arrangement of planetary gears," a gear assembly by which the second motor's output "bypasses the transmission device," and a control system with motoring/recharging/generating modes. That is a power-split hybrid architecture, and it is corroborated by the unusual NPL on the face of the patent (2004/2008/2010/2013 "THS-II-System_Operation" documents and a "Toyota Hybrid Synergy Drive" case study). I could not retrieve claims 1–8. If claims 1–8 are the multi-channel-DC-bus apparatus claims reflected in the abstract and in the EP counterpart's claims 1–15, then two different §103 analyses apply. I therefore give both, labelled Scenario A (claims 9–20, as retrieved) and Scenario B (the multi-channel-DC-bus subject matter reflected in the abstract/BRIEF and in the EP prosecution).

Effective filing date: 30 Jan 2014 (Google Patents: priority 2014-01-30; anticipated expiration 2034-01-30), so the AIA version of §§102/103 governs. All the X-category references below pre-date that date and are §102(a)(1) art; several face-cited US patents (9,108,501; 9,561,719; 2014/0077737; 2016/0152129) post-date it and can only be art under §102(a)(2) ("effectively filed before… names another inventor").

POSITA (my formulation, stated so it can be challenged): a B.S. in electrical or mechanical engineering (or equivalent) with 3–5 years designing electric/hybrid vehicle powertrains and power electronics, including bidirectional DC-DC converters, multi-phase traction inverters, and power-split transmissions.

1. The prior-art record actually on this patent's face

(a) X-category references cited by the EPO against the same family (strongest evidence)

Verbatim from the EP 2913217 search report:

EP 2502773 A2, per the EPO Global Patent Index, discloses "an energy system (102) includ[ing] a bi-directional boost converter (112) coupled to a direct current (DC) link and comprising a plurality of input channels (a,b)… a first energy storage device (108,110) coupled to a first input channel (a,b)… via a DC bus… an auxiliary system (104)… includ[ing] an auxiliary energy source, an auxiliary load and an auxiliary load controller… the system controller configured to… cause the bi-directional boost converter to boost a voltage supplied by the auxiliary energy source and to supply the boosted voltage to the DC link." (http://data.epo.org/gpi/EP2502773B1)

Why this matters: an "X" at the EPO is a completeness finding — the EPO considered this single reference to dispose of inventive step for all claims 1–15 of the parent of the '874. That is the single most probative piece of prior-art evidence in the file, and it is GE's own earlier application (US 13/069,533, filed 23 Mar 2011).

(b) US references cited on the face of the '874 (Justia)

7,063,637 (Yanauchi); 7,207,915 (Oshidari); 7,246,672 (Shirai); 7,932,633 (King); 8,026,638 (King); 8,387,730 (Bouchon); 8,535,200 (Vyas); 9,108,501 (Ortmann); 9,561,719 (Lo); and published apps 2003/0150352, 2004/0069548, 2005/0070401, 2005/0082992, 2006/0169548, 2006/0250902, 2007/0007939, 2007/0158118, 2008/0011528, 2009/0015185, 2009/0115375, 2010/0136379, 2010/0194318, 2010/0219794, 2010/0222953, 2011/0101915, 2012/0103749, 2013/0030630, 2013/0038127, 2013/0138279, 2013/0311023, 2014/0077737, 2016/0152129.

I did not retrieve the specifications of (b), so I use them only where the citation pattern itself is informative (e.g., two King/GE references on the DC-DC-converter/energy-storage interface; Bouchon on selectively coupling a supply to a load).

(c) Non-patent literature (highly diagnostic)

"2004 / 2008 / 2010 / 2013 THS-II-System_Operation" and "Case study: Toyota Hybrid Synergy Drive… Describes first and second generation THS systems prior to priority date." These are only relevant to claims about two motor-generators + engine + planetary power split + an output-coupled motor — i.e., Scenario A.

(d) Foreign art besides the X documents

CN 101729020; DE 102007056722; EP 1306262, 1810861, 2055549, 2159898, 2497666, 2587618; JP H5-176411, H11-208297, 2000-197206, 2003-244801, 2004-260904, 2005-143274, 2006-042510, 2006-230071, 2007-174867, 2007-220976, 2007-274785, 2007-325474, 2008-005625, 2008-312382, 2009-508763, 2009-148139, 2009-183108, 2009-522167, 2010-094016, 2010-115943, 2010-206971, 2012-205495, 2013-147188, 2013-188106, 2013-203109, 2013-207831, 2019-112063; KR 2013-0063893; WO 2007/107458, 2013/008328, 2013/024675, 2013/094043.

2. Scenario B — obviousness of the multi-channel DC bus claims

Assume independent claims along the lines of the abstract: multi-channel DC bus assembly with a first channel and a second channel; a first electromechanical device on the first channel's positive DC link; a second electromechanical device on the second channel's positive DC link; first and second DC-to-AC inverters on those links; a bi-directional voltage modification assembly on the second channel's positive DC link; and a first energy storage system electrically coupled to the first electromechanical device.

Ground B1 — EP 2 502 773 A2 alone (or with a secondary reference).

• Multi-channel DC bus assembly ⇄ bi-directional boost converter (112) "comprising a plurality of input channels (a,b)";
• first energy storage system coupled to the first electromechanical device ⇄ first energy storage device (108,110) "coupled to a first input channel… via a DC bus";
• bi-directional voltage modification assembly on the second channel ⇄ bi-directional boost converter (112) feeding DC link (114) and boosting the auxiliary source's voltage onto that link;
• second electromechanical device / load on a second channel ⇄ auxiliary system (104) with auxiliary energy source (110,126,164), auxiliary load (130,134,158) and auxiliary load controller (132,136,160).
• Motivation: same field (a vehicle propulsion energy system with multiple sources, multiple loads and voltage conversion between them), same problem (the '874's own Background ¶ admits that combining multiple sources "increases the overall size, weight, and cost" and "reduces… operating efficiency"), and it is the applicant's own earlier work — a KSR "predictable use of a known technique to improve a similar device in the same way," with an explicit design incentive (per-channel voltage tailoring to the ratings of each inverter/motor, which the '874 itself states at the 400 V / 630 V example). Reasonable expectation of success: bidirectional boost converters controlling a DC link voltage were routine by 2011–2013.
• Weakness to expect from the patent owner: the '874 requires two independently controlled DC buses whose voltages can differ, whereas EP 2502773 discloses one DC link with multiple converter input channels. If the claims expressly require two separate buses at different voltages, B1 alone is vulnerable → use B2/B3.

Ground B2 — EP 2 502 773 A2 + DE 10 2006 013502 A1 (Siemens). The EPO cited the Siemens document as X against parent claims 1–3, 11 and 13 (abstract, Fig. 1, ¶¶[0072]–[0138]). A Siemens vehicle drive system disclosing plural inverters fed from a common source with intervening DC conversion supplies exactly the element B1 lacks (distinct bus channels per inverter). Motivation: improving a known multi-source/multi-load architecture by the known expedient of giving each inverter its own controlled DC link — a "combination of familiar elements according to known methods [that] yields predictable results" and an "obvious to try" among a finite number of identified solutions.

Ground B3 — DE 10 2006 013502 A1 + EP 2 639 099 A1 (Toyota). Two X documents mapping different claim subsets (1–3, 11, 13 and 1–3, 5, 8, 10) — i.e., the EPO already viewed them as collectively covering the parent's claim set. Their combination is the natural fallback ground if either alone is missing an element.

Ground B4 — dependent features.

• "…boosted voltage different from a voltage of the first/second DC bus": taught or rendered obvious by the multi-input-channel boost converter of EP 2502773; also inherent in the '874's stated ratES (400 V vs 630 V) as a mere selection of voltages.
• "high specific-power energy storage device coupled to a low voltage side": EP 2502773's inverter-input-coupled auxiliary source; also the face-cited King references (7,932,633; 8,026,638), GE's bidirectional DC-DC/energy-storage interface art.
• "transmission coupled to the outputs of both electromechanical devices," "electrically variable transmission… planetary gears and clutches," "internal combustion engine coupled to the transmission": the face-cited US 8,535,200 (Vyas), 9,108,501 (Ortmann), 9,561,719 (Lo), plus the THS-II NPL and EP 2 639 099 A1. Motivation: the '874's own rationale — independent operation of two machines across charge-depleting and charge-sustaining modes to "minimize power loss and maintain a high degree of overall system efficiency" — is precisely what power-split EVTs (THS-II) were built for.
• "auxiliary load coupled to an output of the first electromechanical device"; auxiliary channel inverter; resistive heating element: EP 2502773's auxiliary system/auxiliary load, expressly.
• "coupling device between the positive DC links," operable open/closed: Bouchon (US 8,387,730, coupling a supply to a load) plus the ordinary skill of using a contactor/diode/contactor-resistor; the '874 itself lists these as "non-limiting examples."

3. Scenario A — obviousness of claims 9–20 as retrieved

Claim 9 requires: two traction drive systems; an energy storage device; an ICE; a transmission device with planetary gears coupled to the first drive system and the ICE; a gear assembly between the second drive system and the transmission device so the second machine's output bypasses the transmission device; and a control system that selectively (i) drives the vehicle through the transmission device and the gear assembly, (ii) runs ICE + first drive system in a recharging mode while the second drives through the gear assembly, and (iii) operates the second drive system to generate. Claim 16 is the parallel motor-based claim; claims 10–15 and 17–20 add a DC/DC converter on the storage, a second storage system on that converter, a battery, a wheel/axle assembly, and cross-feeding between machines.

Ground A1 — THS-II NPL + EP 2 639 099 A1 (Toyota). The Toyota Hybrid System II is the canonical power-split architecture: engine on the planetary carrier, MG1 on the sun gear, MG2 coupled to the ring gear/output and then to the final drive/differential — i.e., two electric machines on a common battery, a planetary power-split transmission device tied to the engine, and a second machine whose output reaches the road through the output/gear assembly rather than through the planetary gear set. THS-II also operates in engine-recharging mode (MG1 generates, engine drives) and in regenerative generating mode (MG2 as generator). The applicant's own IDS submissions describe these systems as "prior to [the] priority date." EP 2 639 099 A1, already X against parent claims 1–3, 5, 8, 10, supplies the two-motor/two-inverter, one-bus control arrangement. Motivation: the '874's own stated goal (operating multiple electromechanical devices independently to improve individual and system efficiency, in CD and CS modes, with a heat engine to maintain charge) is exactly the problem THS-II solves; combining a known power-split layout with the claimed control modes is "the mere arrangement of old elements, each performing the function it was known to perform."

Ground A2 — US 8,535,200 (Vyas) and/or US 9,108,501 (Ortmann) in place of, or with, the Toyota art. Both are face-cited hybrid-transmission references and are the sort of art used for "planetary transmission device + two electric machines + selective operating modes." Caveat: I did not read them; 9,108,501 post-dates 30 Jan 2014 and is only art under §102(a)(2) if effectively filed earlier — verify before using.

Ground A3 — claims 10–11 / 17 (DC/DC converter on the energy storage; second energy storage on that converter). EP 2 502 773 A2 (bi-directional boost converter with a plurality of input channels, each coupled to an energy storage device) renders these obvious; so do the King references on the face of the patent.

Ground A4 — claims 14–15, 19–20 (power flow between machines and to the storage). Bidirectional power flow between two inverter-fed machines on a common DC bus, and recuperation into the storage, is the baseline function of every power-split hybrid (THS-II) and of the multi-channel bus systems in EP 2 502 773 A2 / EP 2 639 099 A1.

4. Motivation-to-combine factors common to both scenarios

1. Same field, same problem, common ownership. EP 2 502 773 A2 is GE's own earlier propulsion energy system covering the same multi-source/multi-load, boost-to-DC-link concept; the '874's Background section frames the precise problem and goal, which is an admission of both the problem and the direction of the solution (KSR, Alza line of reasoning on statements of purpose in the specification).
2. KSR "predictable use of a known technique." Adding a second, independently voltage-controlled DC bus channel (via a known bidirectional DC-DC converter) to feed a second inverter/machine is the predictable application of boost-buck converter practice.
3. Design incentives. Component voltage de-rating (the patent's own 650 V vs 900/1200/1800 V device example), fewer parts/less weight when a converter is omitted, and lower-rate energy storage per channel — all cost/weight/performance drivers the patent itself articulates.
4. Finite number of identified solutions / obvious to try. Two channels or three, one shared storage or one per channel, with or without a channel-to-channel coupling device, is the immediately apparent set of options (the '874 enumerates all of them).
5. Reasonable expectation of success in each combination, because each reference already solves a closely related sub-problem in the same environment.

5. Where the obviousness case may fail, and what I could not verify

• Claim-set mismatch (biggest issue). If claims 1–8 are multi-channel-bus apparatus claims, the THS-II NPL and the hybrid-transmission references in §3 may be relevant only to dependent subject matter; if claims 9–20 are the operative claims, EP 2502773's X-citation and the Siemens/Toyota X-citations are largely off-target and the case turns on THS-II + EP 2 639 099 A1. I could not retrieve claims 1–8 or the '874 prosecution history. Pull the full claim set from USPTO PatentCenter for 17/163,646 before using this analysis.
• The "two independent DC buses at different voltages" limitation is the most likely point of escape from EP 2 502 773 A2 taken alone; the Siemens (DE 10 2006 013502 A1) and Toyota (EP 2 639 099 A1) X references are the designed cure.
• I did not read the specifications of DE 10 2006 013502 A1, EP 2 639 099 A1, EP 2 340 957 A1, or the US face-cited references; all mappings above are derived from the EPO report's paragraph/figure citations and from reference titles — they must be claim-charted against the actual text.
• Section 102(a)(2) caveat for post-2014-01-30 face citations.
• No secondary-considerations evidence (commercial success, copying, praise, licensing) is apparent in the record; note, however, that patents sharing this specification are being asserted by Bunker Hill/Dominion Harbor (per the litigation section above), which is evidence about the campaign, not about non-obviousness. On family linkage: the description retrieved from US 10,549,648 (https://patentimages.storage.googleapis.com/33/7e/04/3b0a11140f97f9/US10549648.pdf) is verbatim identical to the '874's description — same figures, same reference numerals, same paragraph text — which indicates the '874 is a same-family continuation of the patent asserted in the Bunker Hill suits. That is a family-level, not claim-level, linkage and does not by itself mean the '874 is asserted.
• Also worth noting: the EP counterpart's file shows EPO "Summons… dated Jun. 4, 2018" for EP 15152810.6 — evidence of a contested novelty/inventive-step fight, followed by a further EP publication (EP 3613625 A2, 2020-02-26). I did not verify the grant outcome for EP 2913217.

Verdict: on the retrieved record, the strongest §103 positions are (i) EP 2 502 773 A2, alone or with DE 10 2006 013502 A1, against the multi-channel-DC-bus claims, given the EPO's own X-findings against claims 1–15 of the parent; and (ii) THS-II NPL + EP 2 639 099 A1, with US 8,535,200/9,108,501 as secondary, against claims 9–20. This is an analytical assessment, not a legal opinion or an invalidity contention; claim scope, priority entitlement, and prosecution-history effects must be confirmed against the actual claim set and file wrapper.