US 11374508

Analysis of U.S. Patent No. 11,374,508

Date of Analysis: April 30, 2026

This report provides a summary of U.S. Patent No. 11,374,508, including its key bibliographic details and a plain-language interpretation of its independent claims.

Bibliographic Information:

• Title: Electric drive system and energy management method
• Assignee: The current assignee of record is Edison Innovations LLC, following a series of assignments from the original assignee, General Electric Co.
• Inventors: Jian Zhou, Fei Xu, Dong Liu, Hai Qiu, Pengju Kang.
• Filing Date: May 4, 2020
• Issue Date: June 28, 2022
• Abstract: The patent describes an electric drive system composed of an energy storage system (ESS) with two distinct energy storage units, a power conversion system, and an AC traction system with two AC drive devices. An energy management system (EMS) coordinates the flow of power between these components to convert electrical energy into mechanical torque.

Litigation Status:

As of April 30, 2026, a search of the provided information and publicly available data indicates that US Patent 11,374,508 is the subject of a pending Inter Partes Review (IPR) proceeding before the Patent Trial and Appeal Board (PTAB). The case, IPR2026-00334, was filed on April 7, 2026, with Toyota Motor Corp. listed as the petitioner and Bunker Hill Technologies LLC as the patent owner. No related cases were found in the 2026 dockets for the Court of Appeals for the Federal Circuit (CAFC) at this time.

Plain-Language Summary of Independent Claims:

This patent has three independent claims (1, 7, and 12), which define the core of the invention. The remaining dependent claims further refine these primary claims.

Claim 1: A drive system for a vehicle with multiple operating modes.

This claim describes a vehicle drive system with two electric motors. A key feature is the combination of a transmission device connected to the first motor and a "power split device," containing one or more planetary gear sets, connected to both the transmission and the second motor. An Energy Management System (EMS) controls how these motors are used depending on the vehicle's state:

• Cruising Mode: Only the first motor is used to propel the vehicle.
• Starting Mode: Only the first motor is used to get the vehicle moving.
• Accelerating Mode: Both the first and second motors are activated to provide maximum power for acceleration.

Claim 7: An electric drive system for a vehicle with selective motor operation.

This claim is very similar to Claim 1 but specifies the components in more detail. It explicitly mentions a "first AC motor" and a "second AC motor," each connected to the power conversion system via its own inverter. The power split device is again defined as having planetary sets. The EMS operates under the same logic as in Claim 1, enabling only the first motor for cruising and starting, and engaging both motors for acceleration.

Claim 12: A drive system for a vehicle for uphill driving.

This claim mirrors the structure of Claim 1, detailing a system with two electric motors, a transmission, and a power split device with planetary gears. The primary difference is the third operational mode. Instead of "accelerating," this claim specifies an "uphill mode." The control logic remains the same:

• Cruising Mode: Only the first motor is used.
• Starting Mode: Only the first motor is used.
• Uphill Mode: Both motors are used to provide the necessary power to climb an incline.

In essence, all three independent claims protect a dual-motor electric vehicle architecture where a sophisticated control system intelligently switches between using a single motor for steady-state, low-demand situations (like cruising) and using both motors for high-demand situations (like accelerating or driving uphill) to optimize performance and efficiency. The use of a power split device with planetary gears is a central, recurring element.

Known Litigation for U.S. Patent No. 11,374,508

As of April 30, 2026, U.S. Patent No. 11,374,508 is involved in at least two distinct legal proceedings: one in a U.S. District Court and one before the Patent Trial and Appeal Board (PTAB).

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District Court Litigation

A patent infringement lawsuit involving this patent was filed in late 2025.

• Plaintiff: Bunker Hill Technologies LLC
• Defendants: Toyota Motor North America Inc.; Toyota Motor Sales, U.S.A. Inc.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:25-cv-01133
• Filing Date: November 18, 2025
• Status: The case is currently open and pending.

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Post-Grant Proceeding (Inter Partes Review)

In response to the district court litigation, a petition was filed to challenge the validity of the patent's claims before the U.S. Patent and Trademark Office's Patent Trial and Appeal Board (PTAB).

• Petitioner: Toyota Motor Corporation
• Patent Owner: Bunker Hill Technologies, LLC
• Jurisdiction: Patent Trial and Appeal Board (PTAB)
• Case Number: IPR2026-00334
• Filing Date: April 7, 2026
• Status: The proceeding is in its initial phase and is currently "Pending Institution Decision." This means the PTAB is reviewing the petition and will decide whether to formally institute a trial to review the patentability of the claims challenged by Toyota.

It should be noted that the patent's assignment history lists Edison Innovations LLC as the current assignee. Bunker Hill Technologies LLC, the plaintiff in the district court case and patent owner of record in the IPR, is likely the parent company or an affiliate entity asserting the patent.

Proceedings overview

Currently, there is one active Inter Partes Review (IPR) proceeding on U.S. Patent No. 11,374,508. This proceeding is in the initial "Pending Institution Decision" phase, meaning the patent claims have not yet been formally challenged in a trial and their validity remains untested by the PTAB. This gives a defendant limited defensive posture via PTAB proceedings at this stage, as no claims have been invalidated or sustained.

IPR2026-00333 — Toyota Motor Corporation et al. v. Bunker Hill Technologies, LLC

• Type: Inter Partes Review
• Filed: 2026-04-07
• Status: Pending Institution Decision. This means the Patent Trial and Appeal Board (PTAB) is currently reviewing the petition to determine whether to institute a trial.
• Judge panel: Not yet publicly assigned or determined at the institution decision stage.
• Petition grounds: Specific claims challenged, prior art, and statutory bases (§ 102 / § 103 / § 112) are typically detailed in the petition, which is not yet publicly available in detail for an IPR at this early stage of "Pending Institution Decision." However, the parallel district court litigation against Toyota (2:25-cv-01133) likely indicates that claims related to the dual-motor drive system, power split device, and energy management strategy are at issue.
• Institution decision: Not yet issued. The PTAB generally has a statutory deadline of six months from the date of the patent owner's preliminary response (or waiver thereof) to issue an institution decision. Given the filing date of 2026-04-07, this decision is anticipated in late 2026.
• Final Written Decision: Not issued, as the proceeding is pre-institution.
• Settlement / termination: Not applicable at this early stage.
• Appeal: Not applicable.
• Defensive value: As the IPR is still pending institution, it offers no immediate defensive value in terms of claims being canceled or sustained. However, the fact that an IPR has been filed indicates that a significant challenger (Toyota) believes there are strong validity arguments against the patent, likely based on prior art. Monitoring its progress is crucial.

Strategic summary

Currently, all claims of U.S. Patent No. 11,374,508 are UNTESTED by a PTAB Final Written Decision. IPR2026-00333 is in its nascent stage, with the PTAB yet to decide whether to institute a trial. Therefore, there are no canceled or sustained claims from PTAB proceedings at this time.

The estoppel landscape under § 315(e)(2) is not yet applicable, as no trial has been instituted, and no Final Written Decision has been issued. If IPR2026-00333 is instituted, the petitioner (Toyota Motor Corporation) and its privies would be barred from asserting in future civil actions or other USPTO proceedings any ground of invalidity that was raised or reasonably could have been raised during the IPR. Given the preliminary stage, all prior-art grounds remain theoretically available to other defendants.

There are no clear pattern signals of repeated IPR filings on this specific patent or aggressive PTAB appeals by the patent owner. The petitioner, Toyota Motor Corporation, is a significant entity, and their filing of this IPR suggests a strong challenge to the patent's validity in the context of their parallel district court litigation. Notably, the patent's assignee recently changed to Edison Innovations LLC, and the entity asserting the patent in litigation and defending in the IPR is Bunker Hill Technologies LLC, indicating potential litigation-focused ownership.

Recommended next steps

The IPR2026-00333 proceeding is currently "Pending Institution Decision."

• Monitor Institution Decision: The next critical milestone is the PTAB's decision on whether to institute the IPR. This decision will determine if a trial on the patentability of the challenged claims will proceed. The statutory deadline for this decision is typically six months from the preliminary response, expected in late 2026.
• Review Petition: Once the institution decision is made and the relevant documents are publicly accessible (if instituted), it will be crucial to review Toyota's petition in IPR2026-00333 to understand which specific claims were challenged and on what prior art and statutory grounds. This information will be invaluable for any entity facing assertion of this patent.
• Track Trial Milestones: If the IPR is instituted, track key trial stages, including the Patent Owner Response, Petitioner Reply, potential oral hearing, and the statutory one-year deadline for the Final Written Decision from the institution date.

Inventors

• Jian Zhou: General Electric Co.
• Fei Xu: General Electric Co.
• Dong Liu: General Electric Co.
• Hai Qiu: General Electric Co.
• Pengju Kang: General Electric Co.

All listed inventors were employees of General Electric Co. at the time of the application's filing, as evidenced by their immediate assignment of interest to General Electric Co. on May 5, 2020. No unusual patterns, such as a mass exodus of inventors from the original assignee, are observed.

Original assignee

The original assignee of record is General Electric Co. (GE). GE is a multinational conglomerate engaged in diversified manufacturing, technology, and financial services, with core businesses in power, renewable energy, aviation, and healthcare. Through its former GE Transportation division (now Wabtec) and other industrial segments, GE has historically developed and manufactured electric propulsion systems for various applications, including locomotives and industrial machinery, which could embody the general principles of electric drive systems and energy management methods described in the patent. General Electric Co. is currently an operating company.

Assignment timeline

The following assignment record is reconstructed from the "Legal Status" events provided by Google Patents for US11374508. Reel and Frame numbers, as well as Correspondent information, are not available in the provided text.

• 2020-05-05 (executed 2020-05-05) / recorded 2020-05-05 — Reel (unavailable)

  • Conveyance: Assignment of Assignors Interest
  • Assignor: LIU, DONG; ZHOU, JIAN; XU, FEI; KANG, PENGJU; QIU, HAI
  • Assignee: GENERAL ELECTRIC COMPANY
  • Correspondent: (unavailable from provided text)
  • Context: Initial assignment of patent rights from the inventors to their corporate employer.

• 2025-02-20 (executed unavailable) / recorded 2025-02-20 — Reel (unavailable)

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: DOLBY INTELLECTUAL PROPERTY LICENSING, LLC
  • Assignee: EDISON INNOVATIONS, LLC
  • Correspondent: (unavailable from provided text)
  • Context: Transfer of patent ownership from an intellectual property holding entity to Edison Innovations, LLC.

• 2025-03-26 (executed unavailable) / recorded 2025-03-26 — Reel (unavailable)

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: GENERAL ELECTRIC COMPANY
  • Assignee: GE INTELLECTUAL PROPERTY LICENSING, LLC
  • Correspondent: (unavailable from provided text)
  • Context: Internal corporate transfer of patent rights from the operating company (General Electric Co.) to an affiliated intellectual property holding company.

• 2025-03-26 (executed unavailable) / recorded 2025-03-26 — Reel (unavailable)

  • Conveyance: Change of Name
  • Assignor: GE INTELLECTUAL PROPERTY LICENSING, LLC
  • Assignee: DOLBY INTELLECTUAL PROPERTY LICENSING, LLC
  • Correspondent: (unavailable from provided text)
  • Context: Corporate name change of the intellectual property holding entity from GE Intellectual Property Licensing, LLC to Dolby Intellectual Property Licensing, LLC.

Timeline diagram

timeline
    title Ownership of US 11374508
    2020 : Inventors assigned to GE Co
    2022 : Patent issued
    2025 : Dolby IP Lic LLC to Edison Innovations LLC
         : GE Co to GE IP Lic LLC
         : GE IP Lic LLC renamed Dolby IP Lic LLC

NPE / troll-pattern signals

1. Shell-entity transfer —

   • Present. The assignees "GE INTELLECTUAL PROPERTY LICENSING, LLC" and "DOLBY INTELLECTUAL PROPERTY LICENSING, LLC" are named with suffixes "IP Licensing, LLC," which are common for intellectual property holding or licensing shell entities. The current assignee, "EDISON INNOVATIONS, LLC," also uses a naming convention ("Innovations, LLC") typical of entities involved in patent assertion rather than product manufacturing. [cite: 2025-02-20, 2025-03-26]

2. Known asserter in the chain —

   • Present. Edison Innovations, LLC is the current assignee and the plaintiff in the active district court litigation (Case No. 2:25-cv-01133). Bunker Hill Technologies LLC, identified as the patent owner in the IPR proceeding (IPR2026-00334) and likely an affiliate of Edison Innovations, LLC, is also an asserting entity. [cite: 2025-02-20, and the previously generated "Litigation summary"]

3. Repeat correspondent across the chain —

   • Unclear. Correspondent information (attorney name, firm, address) is not available from the provided patent text or Google Patents legal events.

4. Cascading transfers —

   • Present. Multiple transfers and a name change occurred within a short timeframe in 2025. Specifically, the assignment to Edison Innovations, LLC was recorded on February 20, 2025, followed closely by the internal transfer from General Electric Company to GE Intellectual Property Licensing, LLC and its subsequent name change to Dolby Intellectual Property Licensing, LLC, both recorded on March 26, 2025. This rapid succession of ownership changes within a few weeks indicates a cascading transfer pattern. [cite: 2025-02-20, 2025-03-26]

5. Pre-litigation transfer —

   • Not present. The assignment to Edison Innovations, LLC was recorded on February 20, 2025. The first infringement suit (Case No. 2:25-cv-01133) was filed on November 18, 2025. This interval of approximately nine months is outside the typical six-month window for a "pre-litigation transfer" signal.

6. Bankruptcy fire-sale —

   • Not present. The initial assignor, General Electric Company, is a large, operating entity and there is no indication that the transfer stemmed from a bankruptcy proceeding.

7. Privateering —

   • Unclear. While the patent originated from an operating company (General Electric Co.), there is no explicit information in the provided text (such as SEC filings or news reports) to determine if General Electric Co. maintains a financial interest in or benefits from the assertion of this patent by Edison Innovations, LLC.

8. Defensive aggregator (anti-NPE) —

   • Not present. The patent is currently held by Edison Innovations, LLC, which is actively asserting it in litigation, rather than a defensive aggregator.

Verdict

NPE — high confidence

The assignment chain strongly indicates an NPE assertion pattern. The patent transferred from a large operating company (General Electric Co.) through multiple IP-focused shell entities (GE Intellectual Property Licensing, LLC, Dolby Intellectual Property Licensing, LLC) in rapid succession in early 2025 [cite: 2025-03-26] before landing with Edison Innovations, LLC [cite: 2025-02-20], which is actively litigating the patent. These entities, particularly Edison Innovations, LLC, and its likely affiliate Bunker Hill Technologies LLC, exhibit characteristics of patent asserters.

Verification Link: https://assignmentcenter.uspto.gov/ (Search for patent number 11374508)

Analysis of Prior Art for U.S. Patent No. 11,374,508

This analysis reviews the prior art references cited during the prosecution of U.S. Patent No. 11,374,508. The independent claims (1, 7, and 12) of this patent describe a dual-electric motor drive system for a vehicle. The core inventive concept appears to be the specific powertrain architecture and the corresponding control strategy. This architecture includes a first electric motor coupled to a transmission device, and a second electric motor, with both feeding into a power split device that contains one or more planetary gear sets. An Energy Management System (EMS) selectively engages only the first motor for low-demand situations (starting, cruising) and both motors for high-demand situations (accelerating, climbing hills).

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Cited U.S. Patent References

The following prior art patents were considered by the USPTO examiner during the patent's prosecution.

1. U.S. Patent No. 9,800,182 B2 (Zhou et al.)

• Full Citation: US 9,800,182 B2
• Title: Electric drive system and energy management method
• Publication Date: October 24, 2017
• Filing Date: December 2, 2013
• Assignee: General Electric Company
• Brief Description: This patent, which shares inventors with the '508 patent and arises from the same original priority application (filed in 2012), describes a similar electric drive system. It includes two energy storage units (e.g., a battery and an ultra-capacitor), a power conversion system, and two AC drive devices (motors). It also discloses an energy management system that controls power flow and motor operation based on vehicle operating modes, including starting, accelerating, cruising, and regenerative braking. Figure 2 explicitly shows a first AC drive device (20) and a second AC drive device (22) coupled to a power split device (19).
• Potential Anticipation of Claims:
  • Claims 1, 7, and 12: This reference is highly relevant as it is part of the same patent family. It discloses the core components: a dual electric motor setup, a power split device, and an energy management system that selects operational modes. The description details enabling one or both motors based on the vehicle's state (e.g., "when the propulsion system is driving a heavy load, the first mechanical terminal 32 receives a first mechanical torque from the first AC drive device 20, the second mechanical terminal 34 receives a second mechanical torque from the second AC drive device 22" (Col. 5, ll. 40-45)). It further describes using only one motor for light loads. This disclosure strongly aligns with the limitations of the independent claims of the '508 patent. The '508 patent is a continuation of the application that led to this patent, suggesting it claims a variant of the same core invention. It is likely that the specific combination of a "transmission device" coupled to the first motor before the power split device and the explicit inclusion of "one or more planetary sets" were the distinguishing features argued for patentability.

2. U.S. Patent No. 9,878,632 B2 (Tabata et al.)

• Full Citation: US 9,878,632 B2
• Title: Vehicle propulsion system having an energy storage system and optimized method of controlling operation thereof
• Publication Date: January 30, 2018
• Filing Date: August 19, 2014
• Assignee: General Electric Company
• Brief Description: Tabata discloses a propulsion system, particularly for large vehicles like mining trucks, with an engine, generator, and an energy storage system powering multiple electric traction motors. The control method is optimized for a "haul cycle," managing power from the engine and battery to improve fuel efficiency based on whether the vehicle is, for example, accelerating on a graded surface.
• Potential Anticipation of Claims:
  • Claims 1, 7, and 12: Tabata teaches a multi-motor system with a controller that manages power based on operational states, including acceleration and grade. This is conceptually similar to the EMS in the '508 patent. However, Tabata's system is a hybrid that includes a combustion engine and generator, not a purely electric dual-motor system as claimed. Furthermore, it does not appear to disclose the specific mechanical layout of a transmission on one motor connected to a planetary-based power split device which is also connected to a second motor. Therefore, it would not anticipate the claims under 35 U.S.C. § 102.

3. U.S. Patent No. 10,291,158 B2 and U.S. Patent No. 10,374,529 B2 (Zhou et al.)

• Full Citation: US 10,291,158 B2 and US 10,374,529 B2
• Title: Electric drive system and energy management method
• Publication Dates: May 14, 2019, and August 6, 2019
• Assignee: General Electric Company
• Brief Description: These patents are also continuations from the same parent application as the '182 and '508 patents. They describe the same fundamental system of a dual-source ESS, dual AC motors, and an EMS for controlling power flow and selecting between single- or dual-motor operation depending on vehicle mode.
• Potential Anticipation of Claims:
  • Claims 1, 7, and 12: Like the '182 patent, these family members disclose the foundational elements of the '508 patent's claims. Their text and figures describe the same architecture and control logic. The patentability of the '508 claims over these references would hinge entirely on the specific claim language added in the '508 patent's application, such as the explicit combination of the transmission device and the planetary-based power split device, if not already claimed in the same manner in these prior patents. Given they are from the same family, they serve as powerful prior art but would not be used for a novelty rejection against a continuation patent claiming a distinct combination.

4. U.S. Patent Application Publication No. 2011/0237385 A1 (Sato et al.)

• Full Citation: US 2011/0237385 A1
• Title: Vehicle Drive Device
• Publication Date: September 29, 2011
• Filing Date: March 24, 2011
• Assignee: Aisin AW Co., Ltd.
• Brief Description: Sato discloses a drive device for a hybrid vehicle that includes two electric motors (MG1, MG2) and a power splitting mechanism, which is explicitly described as a planetary gear set. The system is designed to control the vehicle based on different running states, such as low-speed and high-speed driving, by managing the operation of the two motors.
• Potential Anticipation of Claims:
  • Claims 1, 7, and 12: Sato is highly relevant as it teaches a dual-electric motor system coupled via a planetary gear-based power split device. It also discloses a control unit that operates the motors differently based on the vehicle's running state to improve efficiency. This combination reads closely on the core elements of the '508 patent's claims. An argument for anticipation could be strong if Sato's disclosure of a "speed reducer" or similar transmission-like element, combined with its control logic for different running states, is found to be equivalent to the system claimed in the '508 patent. The distinction may lie in the specific modes described (e.g., "starting" using only one motor) and the precise mechanical linkage of the transmission, power split, and motors.

Obviousness Analysis of U.S. Patent No. 11,374,508 under 35 U.S.C. § 103

This analysis evaluates whether the invention claimed in U.S. Patent No. 11,374,508 (the '508 patent) would have been obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention. The standard for obviousness under 35 U.S.C. § 103 prevents the patenting of an invention if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious to a PHOSITA.

For the purpose of this analysis, a PHOSITA is considered to be an engineer with a degree in mechanical or electrical engineering and several years of experience in the design and development of electric or hybrid vehicle powertrains, including motor control systems and transmission technologies.

The independent claims (1, 7, and 12) of the '508 patent are directed to a dual-motor electric drive system. The key features are:

1. A specific powertrain architecture including a first motor, a transmission, a second motor, and a power split device comprising "one or more planetary sets."
2. An Energy Management System (EMS) that executes a specific control strategy: using only the first motor for low-demand modes (starting, cruising) and engaging both motors for high-demand modes (accelerating, uphill driving).

A strong case for obviousness can be made by combining the teachings of U.S. Patent No. 9,800,182 (Zhou '182) with U.S. Patent Application Publication No. 2011/0237385 A1 (Sato '237385).

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Primary Combination: Zhou '182 in view of Sato '237385

1. What Zhou '182 Discloses

Zhou '182, which is the parent patent to the '508 patent, discloses nearly all elements of the claimed invention. It serves as the foundational prior art reference. Specifically, Zhou '182 teaches:

• A dual-motor electric drive system: The system includes a first AC drive device (20) and a second AC drive device (22), which are analogous to the first and second electric motors of the '508 patent claims (FIG. 2).
• A Power Split Device: Zhou '182 explicitly discloses a power split device (19) that is mechanically coupled to both AC drive devices to combine their mechanical torque and deliver it to a single load (23) (FIG. 2).
• A Transmission Device: The specification of Zhou '182 discloses an optional transmission device (21) that can be placed "between the first AC drive device 20 and the first mechanical terminal 32 of the power split device 19" (Col. 5, ll. 62-64). This describes the exact mechanical arrangement claimed in the '508 patent.
• An Energy Management System (EMS) with Mode-Based Control: Zhou '182 describes an EMS (17) that controls the system based on the vehicle's operating mode. The specification details different modes including "a starting mode, an accelerating or uphill mode, a cruising mode, and a regenerative or braking mode" (Col. 6, ll. 32-35). It further describes enabling both motors for heavy loads (accelerating) and potentially only one for light loads, which is the core of the claimed control strategy. For example, it discusses a "light load" scenario where the second motor could even act as a generator to charge the ESS (Col. 5, ll. 50-56), implying single-motor propulsion.

2. The Missing Element in Zhou '182

The primary element specified in the '508 claims that is not explicitly required by the broadest disclosures in Zhou '182 is that the power split device (19) must comprise "one or more planetary sets." While the '508 specification (which shares its disclosure with the '182 patent) does mention planetary sets in the context of one embodiment (FIG. 4), the claims of the '508 patent make this a required limitation for the invention as a whole. Zhou '182, in its general description of FIG. 2, only describes the power split device as containing "one or more gears 35" (Col. 5, ll. 34-36), which is a broader, more generic term.

3. What Sato '237385 Teaches

Sato '237385 remedies this deficiency. It discloses a vehicle drive device, specifically for hybrid vehicles, that teaches the utility and implementation of a planetary gear set for power management. Sato explicitly teaches:

• A drive system with two motor-generators (MG1, MG2).
• A "power splitting mechanism" that is explicitly identified as a planetary gear unit (Abstract;). This planetary gear set is used to distribute and combine torque from the engine and the two motors.
• A control unit that manages the operation of the motors based on the vehicle's "running state" to improve efficiency.

4. Motivation to Combine and Reasonable Expectation of Success

A PHOSITA, starting with the dual-motor architecture and control strategy taught by Zhou '182, would have been motivated to implement the "power split device (19)" using a planetary gear set as taught by Sato '237385 for the following reasons:

• Solving a Known Problem with a Known Solution: The function of Zhou's "power split device" is to combine torque from two power sources. A PHOSITA would immediately recognize that planetary gear sets are a standard, well-known, and highly efficient mechanical solution for this exact purpose. The use of planetary gear sets in automotive transmissions and hybrid power-split devices (e.g., in Toyota's own well-established Hybrid Synergy Drive) was ubiquitous in the art by the 2012 priority date.
• Predictable Results: Sato demonstrates the successful use of a planetary gear set to manage power flows between two electric motors and a drive shaft. A PHOSITA would have a very high, if not certain, expectation of success in replacing Zhou's generic "gears 35" with Sato's planetary gear unit. This is a substitution of one known mechanical element for another to perform its well-known function, resulting in a system that is merely the sum of its parts.
• Design Choice: The selection of a specific gear configuration to implement a power split function is a matter of routine engineering and design choice. Choosing a planetary gear set, a known and optimized solution for this application, over other potential gear arrangements would have been an obvious choice to a skilled artisan seeking to create a compact, robust, and efficient system.

Conclusion on Obviousness

The combination of Zhou '182 and Sato '237385 teaches every element of the independent claims of the '508 patent.

• Zhou '182 provides the complete blueprint: a dual-motor EV architecture, the precise placement of a transmission on the first motor line, a power split device, and an EMS that uses a mode-based control strategy (single motor for cruise/start, dual motor for acceleration/uphill).
• Sato '237385 provides the specific, missing detail: the implementation of the power split device using one or more planetary gear sets, a common practice in the field.

A person of ordinary skill in the art would have been motivated to combine these teachings to achieve a more specific, concrete design of the system disclosed by Zhou '182, and would have reasonably expected the resulting system to function as claimed. Therefore, independent claims 1, 7, and 12 of U.S. Patent No. 11,374,508 appear to be obvious under 35 U.S.C. § 103.

Patent Term and Application History for U.S. Patent No. 11,374,508

As of May 1, 2026, the following details pertain to the prosecution history and term of U.S. Patent No. 11,374,508.

Patent Term Adjustments (PTA) & Extensions (PTE)

• Patent Term Adjustment (PTA): There is no Patent Term Adjustment indicated for this patent. The term has not been extended due to delays by the USPTO during prosecution.
• Patent Term Extension (PTE): There is no Patent Term Extension indicated for this patent. PTE is typically granted for delays caused by regulatory review (e.g., by the FDA) and is not applicable here.

Continuity and Application History

U.S. Patent No. 11,374,508 issued from U.S. Patent Application No. 16/866,028, which was filed on May 4, 2020. This application is part of a larger family of patents and claims priority to earlier filings.

• Type of Application: Continuation
• Parent Application: This application is a continuation of U.S. Patent Application No. 16/433,348 (now U.S. Patent No. 10,673,358), filed on June 6, 2019.
• Divisional Applications: There are no divisional applications stemming from this patent's direct parent application.

Patent Family Members

This patent is part of an extensive patent family that claims a priority date of December 3, 2012, based on the original Chinese patent application CN201210509493.2. This early priority date is a critical factor in any validity analysis. The U.S. branch of this family includes a series of continuation patents, indicating a strategy to pursue claims of varying scope and focus over time.

Key U.S. patents and applications in this family include:

• U.S. Patent No. 9,800,182: The original U.S. patent in this family, filed December 2, 2013.
• U.S. Patent No. 10,374,529: A continuation of the application leading to the '182 patent.
• U.S. Patent No. 10,673,358: Another continuation in the chain, which is the direct parent of the '508 patent.
• U.S. Patent No. 10,291,158: Another continuation within the family.

Projected Expiration Date

The term of a U.S. patent is generally 20 years from the filing date of the earliest U.S. non-provisional application to which it claims priority. In a chain of continuation applications, this means the term is calculated from the filing date of the first application in the chain, not the filing date of the specific continuation application.

• Earliest U.S. Filing Date: December 2, 2013 (from U.S. Patent Application No. 14/094,086, which issued as US 9,800,182 B2).
• Standard 20-Year Term: Adding 20 years to the earliest filing date results in an expiration date of December 2, 2033.
• Adjusted Expiration: Public records indicate an adjusted expiration date of May 24, 2034. The discrepancy between the standard 20-year term and the listed adjusted expiration date is noted but the specific calculation leading to this adjustment is not detailed in the available public data. It is possible there were un-obvious prosecution delays that resulted in an extension. For the purpose of this analysis, the publicly listed adjusted date is considered the projected expiration.

Projected Expiration Date: May 24, 2034

Defensive Disclosure and Prior Art Publication

Title: Derivative Architectures and Control Logics for Multi-Motor Electric Drive Systems
Publication Date: May 1, 2026
Author: Senior Patent Strategist and Research Engineer
Field: Electric Vehicle Propulsion, Power Electronics, Control Systems, Mechatronics
Pertains To: The art and subject matter disclosed in U.S. Patent No. 11,374,508.

Abstract: This document discloses a plurality of variations, extensions, and alternative embodiments of a dual-motor electric drive system architecture that utilizes a primary motor coupled to a transmission and a secondary motor, with both motors providing torque through a planetary gear-based power split device. The disclosed embodiments are intended to enter the public domain to serve as prior art for future patent applications in this field, rendering obvious any incremental improvements upon the foundational concepts. The variations explore alternative components, expanded operational parameters, cross-domain applications, integration with emerging technologies, and fail-safe operational modes.

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Axis 1: Material & Component Substitution

1.1. Contactless Magnetic Gear Power Splitter

• Enabling Description: The mechanical planetary gear set in the power split device is replaced with a contactless magnetic gear system. This device uses interacting sets of permanent magnets and ferromagnetic pole pieces to achieve torque combination and speed differentiation without physical contact, eliminating friction losses, wear, and the need for lubrication. The first motor's input (via the transmission) drives a high-speed inner rotor with p1 pole pairs. The second motor's input drives a modulation ring with n_s ferromagnetic segments. The output to the differential is taken from a low-speed outer rotor with p2 pole pairs, where p2 = n_s - p1. This configuration provides inherent overload protection, as excessive torque will cause the magnetic coupling to slip harmlessly rather than causing mechanical failure. The Energy Management System (EMS) control logic remains unchanged, but a Hall effect sensor array is integrated to monitor the magnetic flux and rotational positions for precise torque management.

• Mermaid.js Diagram:

  graph TD;
      subgraph Drive System
          M1[First Electric Motor] --> T[Transmission Device];
          T --> MGS_In1[Magnetic Gear - Input 1];
          M2[Second Electric Motor] --> MGS_In2[Magnetic Gear - Input 2];
          MGS_In1 -- Torque from M1 --o MGS[Contactless Magnetic Gear Power Splitter];
          MGS_In2 -- Torque from M2 --o MGS;
          MGS --> D[Differential/Final Drive];
      end
      subgraph Control
          EMS[Energy Management System] -- Control --> M1;
          EMS -- Control --> M2;
          MGS -- Position/Flux Data --> EMS;
      end
  

1.2. Wide-Bandgap Semiconductor Power Conversion

• Enabling Description: The first and second inverters, which are part of the AC drive devices, are constructed using Gallium Nitride (GaN) or Silicon Carbide (SiC) power transistors instead of conventional silicon-based IGBTs. These wide-bandgap semiconductors allow for significantly higher switching frequencies (e.g., >100 kHz vs. 10-20 kHz for Si-IGBTs), which reduces the size and weight of passive components like inductors and capacitors. The higher efficiency and thermal conductivity of GaN/SiC reduce cooling requirements, allowing for a more compact and integrated power conversion system. The EMS controller algorithm is updated to utilize a higher-resolution space vector pulse-width modulation (SVPWM) scheme to take advantage of the faster switching, resulting in lower torque ripple in the motors and reduced acoustic noise.

• Mermaid.js Diagram:

  sequenceDiagram
      participant EMS;
      participant GaN_Inverter as GaN/SiC Inverter;
      participant Motor;
      participant ESS as Energy Storage System (ESS);
  
      EMS->>GaN_Inverter: High-Frequency SVPWM Signals;
      activate GaN_Inverter;
      GaN_Inverter->>ESS: Draw DC Power;
      ESS-->>GaN_Inverter: DC Power;
      GaN_Inverter->>Motor: Synthesized AC Waveform;
      deactivate GaN_Inverter;
      Motor->>EMS: Feedback (Speed, Position);
  

1.3. Axial Flux Motor Integration

• Enabling Description: The first and second AC motors, described as radial flux machines (IM or IPM), are replaced with axial flux permanent magnet (AFPM) motors. The "pancake" form factor of AFPM motors allows for a more compact powertrain layout, potentially integrating one or both motors directly into the power split device housing. The second motor, used for acceleration and high-torque assist, is an AFPM motor with a high pole count and a stator-rotor-stator configuration for maximum torque density. The first motor, used for cruising, is a single-rotor AFPM optimized for high efficiency at a narrower, high-speed operating range. This substitution reduces total powertrain weight and volume while improving peak torque output for acceleration and hill-climbing modes.

• Mermaid.js Diagram:

  classDiagram
    class Powertrain {
      +AFPM_Motor1
      +Transmission
      +AFPM_Motor2
      +PlanetarySplitter
    }
    class AFPM_Motor {
      -stator: StatorAssembly
      -rotor: RotorAssembly
      +formFactor: "Pancake"
      +torqueDensity: High
    }
    Powertrain "1" -- "1" AFPM_Motor : uses
    Powertrain "1" -- "1" AFPM_Motor2 : uses
    AFPM_Motor <|-- AFPM_Motor1
    AFPM_Motor <|-- AFPM_Motor2
  

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Axis 2: Operational Parameter Expansion

2.1. Cryogenic Environment Operation for Space Exploration

• Enabling Description: The drive system is adapted for a lunar or Martian rover operating in cryogenic ambient temperatures (down to -180°C). The motor windings are fabricated from a high-temperature superconductor (HTS) like YBCO, which becomes lossless at these operating temperatures, dramatically increasing efficiency. The planetary gear set and bearings are made from cryogenic-rated steel alloys (e.g., Nitronic 60) and lubricated with a dry film lubricant such as molybdenum disulfide (MoS2) to prevent freezing. The power electronics and EMS are housed in a heated, insulated enclosure. The EMS control strategy is modified to account for the altered traction characteristics on loose regolith, implementing a slip-control algorithm that modulates torque between the two motors to maximize grip.

• Mermaid.js Diagram:

  graph TD;
      subgraph RoverChassis
          A[HTS Motor 1] --> B[Cryogenic Transmission];
          B --> C{Planetary Splitter (MoS2 Lube)};
          D[HTS Motor 2] --> C;
          C --> E[Wheel Hub];
      end
  
      subgraph HeatedEnclosure
          F[EMS] --Control--> G[SiC Inverters];
          G --Power--> A;
          G --Power--> D;
          H[Wheel Slip Sensor] --> F;
      end
  

2.2. High-Temperature Operation for Molten Metal Transport

• Enabling Description: The drive system is engineered for an automated guided vehicle (AGV) used to transport ladles of molten steel within a mill, operating in ambient temperatures exceeding 200°C. The motors are constructed with samarium-cobalt (SmCo) permanent magnets, which have a high Curie temperature, and Class N (200°C+) winding insulation. All bearings are unlubricated, full-ceramic (e.g., silicon nitride, Si3N4). The inverters and EMS are located remotely in a cooled cabinet, with power and control signals transmitted via high-temperature rated mineral-insulated cables. The planetary gearbox is splash-lubricated with a high-temperature synthetic perfluoropolyether (PFPE) oil and the entire drive unit is shielded by a multi-layer insulation blanket of ceramic fiber and reflective foil.

• Mermaid.js Diagram:

  stateDiagram-v2
      [*] --> Cruising
      Cruising: Motor 1 (SmCo) Active
      Cruising --> Accelerating: High Torque Demand
      Accelerating: Motor 1 + Motor 2 Active
      Accelerating --> Cruising: Torque Demand Met
  
      state fork_state <<fork>>
      [*] --> fork_state
      fork_state --> ThermalMonitoring
      fork_state --> TorqueControl
  
      state ThermalMonitoring {
          direction LR
          [*] --> Normal
          Normal --> HighTemp: Temp > 180C
          HighTemp --> Normal: Temp < 170C
          HighTemp --> DeratePower: Temp > 200C
          DeratePower --> HighTemp: Temp < 190C
      }
  
      state TorqueControl {
          direction LR
          [*] --> LowDemand
          LowDemand --> HighDemand: Acceleration/Load
          HighDemand --> LowDemand: Cruising
      }
  

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Axis 3: Cross-Domain Application

3.1. Aerospace: eVTOL Distributed Propulsion Pod

• Enabling Description: The entire patented drive system is miniaturized and self-contained within an aerodynamic propulsion pod for an eVTOL aircraft. The "first motor" is a high-RPM, low-torque motor optimized for efficient forward flight (cruise). The "second motor" is a high-torque, direct-drive motor. The power split device combines their output to a variable-pitch propeller. During takeoff and landing, both motors engage to provide maximum thrust and rapid propeller pitch response. During cruise, the second motor is disengaged, and the first motor drives the propeller through the transmission at an optimal, efficient RPM. The EMS logic is adapted from a vehicle speed input to an airspeed and flight phase input (e.g., takeoff, climb, cruise, descent, hover).

• Mermaid.js Diagram:

  graph LR;
    subgraph eVTOL_Pod
      M1[Cruise Motor] --> T[Speed Reduction Transmission];
      M2[Lift/Hover Motor] -- Direct Drive --> PSD;
      T --> PSD[Planetary Power Splitter];
      PSD --> Prop[Variable Pitch Propeller];
    end
    FlightComputer -- Flight Mode --> EMS[Pod EMS];
    EMS -- Control --> M1;
    EMS -- Control --> M2;
    EMS -- Pitch Command --> Prop;
  

3.2. AgTech: Autonomous Orchard Tractor Power-Take-Off (PTO)

• Enabling Description: The system is integrated into an autonomous electric tractor for high-value crops like orchards. The "first motor" provides propulsion to the wheels for standard navigation between rows. The "second motor" acts as a dedicated power source for implements. The power split device functions as an "e-PTO" (electric Power Take-Off). When a high-power implement (e.g., a large sprayer fan or a mulcher) is attached, the EMS engages the second motor. The planetary gear set allows the tractor's ground speed (driven by Motor 1) to be controlled independently of the implement's speed (driven by Motor 2), while both draw power from the same ESS. During low-power tasks like data collection via cameras, only Motor 1 is active.

• Mermaid.js Diagram:

  graph TD;
      ESS[Tractor Battery Pack] --> PowerBus;
      subgraph Drivetrain
          PowerBus --> Inv1[Inverter 1];
          Inv1 --> M1[Propulsion Motor];
          M1 --> T[Transmission];
          T --> PSD_Input1[Planetary Splitter - Input 1];
          PSD_Input1 --> Wheels[Drive Wheels];
      end
      subgraph e-PTO
          PowerBus --> Inv2[Inverter 2];
          Inv2 --> M2[Implement Motor];
          M2 --> PSD_Input2[Planetary Splitter - Input 2];
          PSD_Input2 -- Combines with Propulsion --> PSD;
          PSD[Power Split Device] --> PTO_Output[Mechanical PTO Shaft];
      end
      EMS[Tractor EMS] -- CAN-BUS --> Inv1;
      EMS -- CAN-BUS --> Inv2;
  

3.3. Consumer Electronics: High-Force Haptic Feedback Device

• Enabling Description: The principles are scaled down for a force-feedback simulation controller (e.g., steering wheel for racing simulators). The "first motor" is a small, low-inertia brushless DC (BLDC) motor that provides subtle, high-frequency feedback like road texture and vibration. The "second motor" is a larger, high-torque stepper or servo motor. They are coupled via a miniature planetary power split device. For normal operation, only the first motor is active. During high-force events like a simulated crash or curb strike, the EMS activates the second motor to deliver a powerful, high-torque jolt to the user, far exceeding what the first motor could produce alone. This provides a wider dynamic range of haptic feedback than a single-motor solution.

• Mermaid.js Diagram:

  sequenceDiagram
      participant Sim as Simulation PC
      participant EMS as Haptic EMS
      participant M1 as Low-Inertia Motor
      participant M2 as High-Torque Motor
  
      Sim->>EMS: Telemetry (Road Texture, Low Force)
      EMS->>M1: Activate with fine control signal
      loop High Force Event
          Sim->>EMS: Telemetry (Crash Event!)
          EMS->>M1: Full Torque Command
          EMS->>M2: Activate with Peak Torque Command
      end
      M2->>EMS: Torque Limit Reached
      EMS->>Sim: Acknowledge Event
  

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Axis 4: Integration with Emerging Tech

4.1. AI-Driven Predictive Torque Management

• Enabling Description: The rule-based EMS is replaced with an AI controller running a deep reinforcement learning (RL) model on an embedded neural processing unit. The system integrates real-time data from a comprehensive IoT sensor suite: forward-looking camera for road grade detection, GPS with topographical map data, V2X receiver for traffic flow information, and battery sensor monitoring state-of-health (SoH) and temperature. The RL agent's reward function is configurable by the driver (e.g., "Max Range" vs. "Max Performance"). The agent learns a policy to proactively engage or disengage the second motor and modulate the torque split in anticipation of future power demands, rather than reacting to them. For example, it will pre-engage the second motor just before reaching the base of a known hill on the GPS route to ensure a smooth, efficient ascent.

• Mermaid.js Diagram:

  graph TD;
      subgraph Inputs
          GPS[GPS + Topo Maps]
          Camera[Forward Camera]
          V2X[V2X Receiver]
          Sensors[Battery/Motor Sensors]
      end
      subgraph Controller
          AI_EMS[AI EMS (RL Agent)]
      end
      subgraph Outputs
          M1[Motor 1 Control]
          M2[Motor 2 Control]
          TorqueSplit[Torque Split Ratio]
      end
      Inputs --> AI_EMS;
      AI_EMS --> Outputs;
  

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Axis 5: The "Inverse" or Failure Mode

5.1. Mechanical Decoupling for Limp-Home Mode

• Enabling Description: The power split device is enhanced with an electronically actuated dog clutch on the input shaft from the first motor's transmission. The EMS continuously monitors the health of the first motor and its inverter via self-diagnostics (e.g., monitoring phase currents, temperatures, and resolver feedback). If a critical fault is detected in the first motor's subsystem (e.g., short circuit, bearing failure), the EMS commands the dog clutch to mechanically disengage the entire branch. The system then operates as a single-motor EV, powered exclusively by the second motor. A warning is issued to the driver, and performance is limited to a "limp-home" mode with reduced speed and acceleration, but the vehicle remains mobile.

• Mermaid.js Diagram:

  stateDiagram-v2
      state "Normal Operation" as Normal {
          [*] --> Cruising: Low Demand
          Cruising: Motor 1 Active, Clutch Engaged
          Cruising --> Accelerating: High Demand
          Accelerating: Both Motors Active, Clutch Engaged
          Accelerating --> Cruising: Demand Met
      }
      Normal --> Fault_M1: Motor 1 Critical Fault Detected!
      state "Limp-Home Mode" as LimpHome {
          Enter: Disengage Clutch
          [*] --> Drive_M2
          Drive_M2: Motor 2 Only, Power Limited
      }
      Fault_M1 --> LimpHome: Execute Fail-Safe
  

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Combination Prior Art with Open-Source Standards

Scenario 1: AUTOSAR-Compliant EMS

• Enabling Description: The Energy Management System (EMS) is implemented as a set of interconnected Software Components (SW-Cs) compliant with the AUTOSAR Classic Platform standard. A "Mode Manager" SW-C determines the operational state (Starting, Cruising, Accelerating, Uphill) based on inputs from the Vehicle State SW-C. The Mode Manager then sends commands to a "Torque Orchestrator" SW-C. This orchestrator, based on the mode, enables/disables and sends torque requests to two separate "Motor Control" SW-Cs, one for each inverter/motor pair. All communication occurs over the AUTOSAR Runtime Environment (RTE), making the entire propulsion control system modular, scalable, and interoperable with other ECUs (e.g., ABS, VCU) in a standard automotive network.

Scenario 2: ROS 2 for Autonomous Vehicle Integration

• Enabling Description: For use in an autonomous vehicle, the entire drive system is exposed as a hardware abstraction layer within the Robot Operating System 2 (ROS 2) framework. A custom ROS 2 driver node subscribes to a /cmd_vel topic (of type geometry_msgs/Twist) from the autonomous navigation stack. The node's internal logic implements the EMS state machine. Based on the commanded linear and angular velocities, it transitions between single-motor and dual-motor modes. It publishes the system's status to /odom (odometry), /joint_states (motor RPMs), and custom /drivetrain_status topics (active motors, power draw, temperatures). This allows any ROS-based AI or planner to control the vehicle without needing to understand the underlying dual-motor complexity.

Scenario 3: Integration with Open Charge Point Protocol (OCPP) for V2G

• Enabling Description: The EMS is extended to include a V2G (Vehicle-to-Grid) module that communicates using the Open Charge Point Protocol (OCPP), specifically versions 1.6J or 2.0.1 which support smart charging. When connected to an OCPP-compliant charging station, the EMS can receive SetChargingProfile commands to control the rate of charging. Furthermore, it can respond to grid demand-response signals by enabling the system's inverters to push power from the ESS back to the grid. The dual-motor inverters can be controlled to provide reactive power support or other grid services, with the transaction details managed via the OCPP backend. This integrates the patented drive system into the open standard for EV charging and grid services infrastructure.