PTAB

IPR2026-00022

Generac Power Systems Inc v. J Carl Cooper

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petition

1. Case Identification

2. Patent Overview

  • Title: POWER SOURCE LOAD CONTROL
  • Brief Description: The ’857 patent discloses methods for controlling backup power sources by altering the AC power frequency in response to the electrical load. The system can determine remaining available power and, if an overload is imminent, alter its frequency to manage the load.

3. Grounds for Unpatentability

Ground 1: Obviousness over Lasseter and Lopes - Claims 1-6, 8, 13-15, 39-43, 61-62, and 65 are obvious over Lasseter in view of Lopes.

  • Prior Art Relied Upon: Lasseter (Application # 2006/0208574) and Lopes (J.A. Peças Lopes et al., Defining Control Strategies for MicroGrids Islanded Operation, IEEE TRANSACTIONS POWER SYSTEMS (May 2006)).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Lasseter teaches a distributed energy resource (DER) system with microsources that control their output frequency in response to load. Specifically, Lasseter’s controllers reduce operating frequency to increase power output up to a maximum rated power (Pmax) at a minimum frequency. Petitioner contended that exceeding Pmax constitutes an "overload" per the ’857 patent. While Lasseter teaches preemptively disconnecting loads, it does not detail a responsive strategy for when load exceeds generation capacity. Lopes addresses this gap by teaching a responsive, frequency-based load-shedding strategy for islanded microgrids, where under-frequency relays disconnect less important loads when a high imbalance between load and generation causes frequency deviations.
    • Motivation to Combine: A POSITA would combine Lopes with Lasseter to address the overload scenario that Lasseter identifies but does not fully solve. The primary motivations included: (1) implementing a well-known, responsive load-shedding technique to manage overload conditions instead of relying on inefficient excess generation capacity; (2) avoiding the drawbacks of Lasseter’s preemptive load disconnection, thereby allowing non-critical loads to remain powered during periods of low demand; and (3) ensuring critical loads receive power by shedding only non-essential loads when necessary.
    • Expectation of Success: Petitioner asserted a POSITA would have a reasonable expectation of success, as the combination integrates a known solution (Lopes’s load-shedding) into a system (Lasseter’s) to address a known problem (overload) in a predictable manner.

Ground 2: Obviousness over Lasseter, Lopes, and Miller - Claims 5-12 and 16 are obvious over the combination of Lasseter, Lopes, and Miller.

  • Prior Art Relied Upon: Lasseter (Application # 2006/0208574), Lopes (IEEE article), and Miller (Patent 7,274,975).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds on the Lasseter-Lopes combination by adding the teachings of Miller. Miller discloses an integrated control device that manages energy from various sources, including rechargeable batteries, for maximum efficiency. Its controller and optimization algorithm determine when to charge or discharge batteries based on factors like grid electricity price, availability of renewable sources, and battery charge levels. This addresses claim limitations related to rechargeable batteries and the control of their charging from various sources (e.g., grid, solar, internal combustion engine).
    • Motivation to Combine: While Lasseter-Lopes contemplates batteries, it lacks detailed teachings on managing their charging and discharging. A POSITA would incorporate Miller’s control device to add sophisticated, cost-effective, and efficient battery management to the Lasseter-Lopes system. This would enable the system to coordinate multiple power sources (grid, solar, etc.) to charge batteries when most efficient (e.g., low grid cost) and ensure the battery is available when needed.
    • Expectation of Success: Petitioner argued success would be expected because it involves applying Miller's well-known battery management techniques to the known microsource configuration of Lasseter-Lopes. This combination augments the base system's functionality without changing its fundamental operating principles.

Ground 3: Obviousness over Lasseter, Lopes, and Baldassarre - Claims 13, 44, and 63-64 are obvious over the combination of Lasseter, Lopes, and Baldassarre.

  • Prior Art Relied Upon: Lasseter (Application # 2006/0208574), Lopes (IEEE article), and Baldassarre (Application # 2010/0019574).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground adds Baldassarre to the Lasseter-Lopes combination to address claims requiring user-defined load priorities. Lopes teaches shedding "less important" loads based on frequency drops but does not disclose a user interface for defining or prioritizing these loads. Baldassarre discloses a processor-based control system with a user-interactive device that allows a user to program load priorities, as well as sequence load shedding and reconnection in real-time.
    • Motivation to Combine: A POSITA would be motivated to integrate Baldassarre's user interface and priority-based load management into the Lasseter-Lopes system to add user configurability. This provides a desirable improvement over fixed, inflexible frequency thresholds, allowing users to tailor the load-shedding response to their specific needs, thereby improving system usability, efficiency, and safety.
    • Expectation of Success: Petitioner asserted the combination would predictably yield a system with user-configurable, frequency-responsive load management. Integrating Baldassarre’s programmable interface with Lasseter-Lopes's control logic would involve routine design adaptation, as both systems utilize processor-based controls and relay switching.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 16 based on the combination of Lasseter, Lopes, Baldassarre, and Miller, arguing the motivations to combine are complementary and apply collectively.

4. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-16, 39-44, and 61-65 of the ’857 patent as unpatentable.