The US Court of Appeals for the Federal Circuit yesterday ordered the International Trade Commission (ITC) to review again whether Mitsubishi violated GE’s ‘985 patent for low-voltage ride-through (LVRT) technology.
Previously, the ITC had ruled that GE did not use the ‘985 patent in the US and therefore the ITC could not penalise Mitsubishi for infringement.
The reversal of the ITC’s ‘domestic industry’ finding means that Mitsubishi could now, after another ITC review, be found to infringe the LVRT patent.
It was a partial victory for GE, the US’s largest turbine maker, which, in 2010, accused its smaller wind-industry rival Mitsubishi of infringing three GE’ patents by importing the Mitsubishi flagship 2.4MW turbine to the US.
The LVRT patent finding, however, is complicated. An ITC judge has found that California engineer Thomas Wilkins was an unnamed co-inventor of the widely-used ‘985 patent. Wilkins could thus license the technology and collect royalties, said the judge.
In addition, Wilkins has been sued by GE over the ‘985 patent. The US Patent Office is currently re-examining the patent.
LVRT, required by US regulators, allows turbines to ‘ride through’ sudden dips in grid voltage.
Also yesterday, the appeals court upheld the ITC’s decision that Mitsubishi’s 2.4MW turbine does not infringe GE’s’221 patent, also for a form of LVRT.