Federal Circuit Remands Issues Decided By Initial Determination But Not Substantively Reviewed By The ITC

Last Month at the Federal Circuit - March 2012

Judges: Rader, Newman (author), Linn

[Appealed from ITC]

In General Electric Co. v. International Trade Commission, No. 10-1223 (Fed. Cir. Feb. 29, 2012), the Federal Circuit affirmed-in-part, vacated-in-part, reversed-in-part, and remanded the ITC's findings in a Section 337 investigation concerning wind turbines imported by Mitsubishi Heavy Industries, Ltd. and Mitsubishi Power Systems Americas, Inc. (collectively "Mitsubishi"). Mitsubishi's turbines were investigated in view of three wind turbine patents owned by General Electric Company ("GE").

It was undisputed during the ITC investigation that both Mitsubishi and GE sell variable speed wind turbines in the United States. Moreover, the turbines of each party employ "doubly-fed" induction generators, meaning that they utilize two electromagnetic fields to generate electricity for transmission over the power grid. While the doubly-fed design is generally more efficient at harvesting power than singly-fed generators, a downside occurs when the grid experiences irregularities, such as lightning strikes, downed lines, and short circuits. During those periods, large voltage differences between the stator coils and grid coils generate high current levels that can damage the converters used for feeding the rotor current. To address this problem, the Mitsubishi and GE turbines employ circuitry that decouples the rotor windings from the circuit during periods of elevated current. Then, to resume operation, the turbines trigger recoupling of the rotor windings. Mitsubishi's turbines recouple after a preset period of time, while GE's turbines recouple once the current levels decline to an acceptable level. In addition, GE's turbines employ a shunt circuit within the rotor inverter that responds to signals during a low-voltage event to enable the turbine to maintain steady voltage.

The ALJ found that all three of GE's patents, U.S. Patent Nos. 7,321,221 ("the '221 patent"), 6,921,985 ("the '985 patent"), and 5,083,039 ("the '039 patent"), were valid and infringed. The ALJ also found that GE had established a domestic industry with respect to the '985 and '039 patents, but not the '221 patent. The ALJ issued an initial determination finding a Section 337 violation. The ITC reviewed the ALJ's initial determination and reversed the ALJ's ruling. The ITC concluded that the '221 and '039 patents were not infringed, the '039 patent is not invalid by reason...