Vestas-American Wind Technology, Inc. v. General Electric Co.

1. Case Identification

• Patent #: 6,921,985
• Filed: May 4, 2018
• Petitioner(s): VESTAS-AMERICAN WIND TECHNOLOGY, INC. and VESTAS WIND SYSTEMS A/S
• Patent Owner(s): GENERAL ELECTRIC CO.
• Challenged Claims: 1, 3, 6-8, 12, 14, 29-30, 32-45, and 64

2. Patent Overview

• Title: Wind Turbine Generator with Low Voltage Ride-Through Capability
• Brief Description: The ’985 patent relates to wind turbines with "low voltage ride-through" (LVRT) capability. The invention describes a system that allows a wind turbine to remain connected to an electric grid during a grid fault (a low voltage event) by using an uninterruptible power supply (UPS) to power critical components, such as the blade pitch control system.

3. Grounds for Unpatentability

Ground 1: Obviousness over Cousineau and EON - Claims 1, 3, 6-8, 12, 14, 29-30, 32-45, and 64 are obvious over Cousineau in view of EON.

• Prior Art Relied Upon: Cousineau (Patent 6,265,785) and EON (E.ON Netz GmbH, "Supplemental Network Connection Rules for Wind Energy Systems," Dec. 1, 2001).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Cousineau disclosed all key elements of the challenged claims, including a wind turbine with a blade pitch control system and a turbine controller powered by a secondary, non-volatile power source (like a battery or capacitor) to provide overspeed protection during a power outage. Independent claim 1 recites a wind turbine with a generator, a blade pitch control system, a turbine controller, a first power source for normal operation, and a UPS to provide power during a low voltage event where the generator remains connected to the grid. Petitioner asserted Cousineau taught these elements to prevent damage from mechanical braking, which inherently provided the capability to ride through a fault.
  • Motivation to Combine: Petitioner asserted that the EON grid code, which was published before the ’985 patent's filing, provided the explicit motivation for a person of ordinary skill in the art (POSA) to adapt Cousineau's system for LVRT. EON required wind turbines to remain connected to the grid during severe voltage drops (down to 15% of nominal voltage) for up to 3 seconds. A POSA, faced with the EON requirements, would have been motivated to use Cousineau's UPS-backed pitch control system not just to avoid halting the turbine, but to actively manage rotor speed and remain operational to comply with the grid code.
  • Expectation of Success: Petitioner contended that a POSA would have a high expectation of success because Cousineau already taught the necessary components (UPS-backed pitch control) and the problem to be solved (managing the turbine during a power loss). Applying this known solution to meet the specific voltage and time parameters of the EON grid code was presented as a predictable design choice.

Ground 2: Obviousness over Enercon, EON, and Rosch - Claims 1, 3, 6-8, 12, 14, 29-30, 32-45, and 64 are obvious over Enercon in view of EON and Rosch.

• Prior Art Relied Upon: Enercon (European Commission, Project Report: "WEGA II Large wind turbine scientific evaluation project," 2000), EON (as in Ground 1), and Rosch (PC Magazine, May 27, 1986).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Enercon described the E-66 wind turbine, which used a battery-backed, active pitch control system. However, in response to a grid failure, Enercon's system was configured to disconnect from the grid and bring the rotor to a complete standstill ("feathered" position). Rosch was cited as general prior art teaching the widespread use and purpose of a UPS to power critical computer components during power failures, establishing it as a well-known solution.
  • Motivation to Combine: The primary motivation was again the EON grid code. A POSA seeking to make the Enercon turbine compliant with EON's LVRT requirements would be motivated to modify its behavior. Instead of using the existing battery system to shut down, a POSA would modify the control logic to use that same battery power to continue operating the pitch control system, manage rotor speed, and ride through the low-voltage event without disconnecting. Rosch reinforced the obviousness of using a UPS for any critical control system, making the modification a simple application of a known technique to a known problem.
  • Expectation of Success: Petitioner asserted a high expectation of success because Enercon already provided the necessary hardware (a battery-backed pitch control system). The only required change was to the control software to implement a ride-through strategy instead of a shutdown strategy, a modification well within the skill of a POSA, especially when guided by the explicit requirements of the EON grid code.

4. Key Claim Construction Positions

• Petitioner argued that several claim terms should be construed as means-plus-function limitations under pre-AIA §112(6), as they failed to recite sufficient structure. This was central to their argument, as it allowed mapping the prior art's function without needing identical structure. Key terms included:
  • "means for providing power to wind turbine components using a generator": Petitioner argued the corresponding structure is electrical wiring, optionally with transformers.
  • "means for detecting a low voltage event": Petitioner asserted the structure is a turbine controller using one or more system sensors.
  • "means for providing power from an uninterruptible power supply": Petitioner identified the structure as electrical wiring.
• "turbine controller": Petitioner proposed this term should be construed broadly to include one or more circuits or microprocessors that control any of the turbine's electromechanical systems, not necessarily a single, integrated unit.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 3, 6-8, 12, 14, 29-30, 32-45, and 64 of Patent 6,921,985 as unpatentable under 35 U.S.C. §103.