Green Patent Blog®

In previous posts here and here, I discussed the General Electric Company’s (GE) two wind turbine patent actions against Mitsubishi, one in the U.S. International Trade Commission (ITC) and the other in federal court in the Southern District of Texas. 

Last month GE added a third case to the mix when it sued Mitsubishi for infringement of two patents relating to a wind turbine base frame and zero voltage ride through (ZVRT) technology. 

Filed in the Northern District of Texas in Dallas, the complaint (gecomplaint.pdf) identifies Mitsubishi’s 2.4 megawatt wind turbine as the allegedly infringing product.

The patents-in-suit are U.S. Patent Nos. 6,879,055 (’055 Patent) and 7,629,705 (’705 Patent).  The ‘055 Patent is directed to a two-part base frame for arranging a drive train on the tower of a wind turbine.

The upper part (6) of the base frame carries the drive train, and the lower part (16) of the base frame has an azimuthal drive device (23), which rotates azimuthally to adjust the rotor axis as a function of wind direction. 

The connection point (15) that joins the upper and lower parts of the base frame extends along a horizontal cross-section having a larger dimension in the direction of the rotor axis than in the perpendicular direction. 

According to the ‘055 Patent, this construction of the connection point (15) is favorable for absorption of stress from the rotor.  The two-part design also makes transport and assembly of the base frame easier.

The ‘705 Patent, which issued in December 2009, relates to methods of facilitating zero voltage ride through so the turbine can remain online during voltage dips down to zero volts. 

As the ‘705 Patent explains, some gearless direct drive wind turbine generators include power converters, and both the generators and the converters are susceptible to grid voltage fluctuations. 

The patented methods mitigate wind turbine generator trips during events in which voltage amplitude decreases to zero volts, as opposed to known low voltage ride through methods that can handle less extreme voltage drops.

The patented systems and methods include a phase-locked loop (PLL) regulator to receive voltage measurement signals from a plurality of voltage transducers.  The PLL regulator includes a PLL that receives the sinusoidal voltage measurement signals.

If a voltage amplitude is outside a pre-determined range, an algorithm within the PLL generates a control signal and the PLL regulator changes to a different mode or state of operation.  A plurality of states of operation are possible, with varying parameters such as gain constants.

According to the ‘705 Patent:

the plurality of states of operation facilitate zero voltage ride through (ZVRT) as well as other grid faults while also facilitating normal operation   

This lawsuit comes shortly after the ITC terminated GE’s complaint against Mitsubishi.  GE’s infringement suit in the Southern District of Texas has been stayed pending a final determination of the ITC case.

Mitsubishi has pulled off a come-from-behind victory in a wind turbine patent case against General Electric (GE) in the U.S. International Trade Commission (ITC). 

In a Notice issued on January 8th, the ITC terminated its investigation of GE’s complaint and found Mitsubishi did not violate any claims of the three patents asserted by GE.

GE filed the complaint in March of 2008, accusing Mitsubishi of infringing certain claims of U.S. Patent Nos. 5,083,039 (’039 Patent) and 6,921,985 (’985 Patent).  GE later amended the complaint to include U.S. Patent No. 7,321,221 (’221 Patent). 

The ‘039 Patent is entitled “Variable speed wind turbine” and is directed to a variable speed turbine that provides responsive control of generator torque. 

The ‘985 Patent is entitled “Low voltage ride through for wind turbine generators” and is directed to a wind turbine that includes a blade pitch control system and a turbine controller coupled with the blade pitch control system. 

The ‘221 Patent is entitled “Method for operating a wind power plant and method for operating it” and is directed to improved methods for stabilizing the supply voltage to a wind turbine after voltage drops without jeopardizing the electrical components of the turbine.  

A more detailed discussion of the asserted patents can be found in my previous post on the federal court case between GE and Mitsubishi here.

The ITC decision to let Mitsubishi off the hook reversed an administrative law judge’s (ALJ) ruling in August of last year that Mitsubishi had violated the ‘039 and ‘985 Patents. 

Shortly after the ALJ decision, an ITC investigative attorney filed a petition with the ITC commissioners questioning certain infringement findings and raising concerns about whether GE met the domestic industry requirement of Section 337.

The Notice of Termination clears the way for Mitsubishi to assemble its imported turbine components and build a $100 million wind power plant in Forth Smith, Arkansas.

The General Electric Company (GE) is the U.S. leader in installed wind capacity, and patent enforcement plays a part in that success.  Earlier this month GE sued Mitsubishi in the Southern District of Texas, alleging that its Japanese competitor’s 2.4MW turbine models infringe U.S. Patent Nos. 5,083,039 (’039 Patent), 6,921,985 (’985 Patent) and 7,321,221 (’221 Patent).

The complaint (ge_complaint.pdf) cites the sale and installation of Mitsubishi’s turbines at the Penascal and Gulf Wind wind farms in Kenedy County, Texas as infringing activities.

The asserted patents relate to energy conversion and control technology for wind turbines.  The ‘039 Patent, which issued back in 1992, is directed to a variable speed wind turbine that provides responsive control of generator torque.  The patented turbine controls the torque reacted by the generators (16, 18) by controlling the stator currents or voltages and basing commands on turbine performance parameters.

Shaft speed sensors (42, 44) monitor the rotor speed of the generators and supply rotor speed information to the generator controllers (38, 40) and to a torque command device (46).  Specifically, the torque command device (46) monitors wind turbine performance parameters and sends torque control signals to the generator cotrollers (38, 40) and pitch angle control signals to a pitch control unit (48). 

The ‘985 Patent is directed to a wind turbine that includes a blade pitch control system and a turbine controller coupled with the blade pitch control system.  To increase the reliability of the turbine’s power supply, the turbine controller causes the blade pitch control system to vary pitch in response to transitions between different power sources.

The ‘221 Patent is directed to improved methods for stabilizing the supply voltage to a wind turbine after voltage drops without jeopardizing the electrical components of the turbine.  According to the ‘221 Patent, a key step in the patented method is to resume feeding of the rotor current after variations in voltage amplitude cause decoupling of the feed-in unit.

This lawsuit appears to be the second part of a two-pronged strategy to enforce these patents against Mitsubishi.  As mentioned in the complaint, GE obtained an initial favorable decision from the U.S. International Trade Commission (ITC) that Mitsubishi had not successfully challenged the validity and enforceability of these patents and that the accused wind turbines infringe the patents (ge_itc_initial_determination.pdf) (see the CleanIP blog post here).

The ITC action and this new federal court case squeeze Mitsubishi both with respect to importation of its turbines at the U.S. border and as to domestically produced equipment.

In a previous post, I wrote about Nordic Windpower’s (Nordic) patent pending flexible “teeter hub” technology for its two-bladed wind turbines. 

Nordic also has begun to enforce its increasingly valuable trademark, reflecting a recent uptick in litigation involving eco-marks (trademarks that communicate environmentally friendly products or services).

Nordic owns U.S. Trademark Registration No. 3,536,392 for the NORDIC WINDPOWER mark for “wind turbines; wind-powered electricity generators” in Class 7 (’392 Registration) (392_reg.pdf). 

Last month Nordic sued Nordic Turbines, Inc. (NTI), a wind turbine manufacturing venture, alleging that NTI’s use of the term “Nordic” to market and sell wind turbines and raise investment capital for the manufacture of wind turbines infringes the ‘392 Registration.

According to the complaint (nordic_complaint.pdf), filed in federal court in San Francisco, NTI changed its name in June 2009 from Vista Dorada Corp. to Nordic Turbines to benefit from Nordic’s goodwill and market presence.

In addition to trademark infringement, the complaint alleges that NTI misappropriated text and images from a Nordic confidential management presentation that includes details about Nordic’s patent pending technology.

Nordic also asserts trade dress protection for a blue and orange color scheme the company uses in its advertisements and promotional material (trade dress refers to the visual look and feel of a product or its packaging).  The complaint alleges that NTI is using an identical blue and orange color scheme.

Nordic has requested a preliminary and permanent injunction with respect to the alleged trademark and trade dress infringement and requests that the court make NTI do corrective advertising to dispel any consumer confusion.

In another wind energy eco-mark suit, Jacobs Wind Electric Co. (Jacobs), a Minneapolis-based consumer wind system designer, recently moved for partial summary judgment of trademark cancellation and fraud claims brought by Minnesota wind system maker Wind Turbine Industries Corp. (WTIC) in a dispute over rights to certain JACOBS trademarks.

Jacobs owns U.S. Trademark Registration 1,532,714 for the mark JACOBS WIND ENERGY SYSTEMS & Design (shown above) for wind energy conversion apparatus in Class 7 (’714 Registration) (714_reg.pdf).  Jacobs also owns U.S. Trademark Application No. 76/677,473 for the JACOBS mark for the same goods (’473 Application) (473_app.pdf).

In January, WTIC sued Jacobs in U.S. District Court in Minnesota, requesting cancellation of the ‘714 Registration and the ‘473 Application on the basis that Jacobs fraudulently obtained the ‘714 Registration for the design mark and is fraudulently seeking registration of the JACOBS mark. 

WTIC asserts that the JACOBS mark was owned by an earlier Jacobs corporate entity, which subsequently changed its name to Earth Energy Systems, Inc. (EESI).   

According to the complaint (wind_turbine_industries_complaint.pdf), EESI assigned to the current Jacobs only limited use of the mark, and Jacobs agreed not to use the JACOBS mark in connection with the manufacture or sale of wind energy equipment.  The complaint further alleges that EESI assigned the the JACOBS mark in its entirety to WTIC.

WTIC accused Jacobs of fraud in prosecuting the application that matured into the ‘714 Registration and the ‘473 Application by swearing to the U.S. Patent and Trademark Office (PTO) that it exclusively owned the mark.

Jacobs’ summary judgment motion (jacobs_wind_motion.pdf) disputes WTIC’s ownership story.  According to the motion papers, Jacobs was granted a perpetual license to use the JACOBS mark by EESI, and WTIC was subsequently granted a limited license to the mark subject to pre-existing licenses.

Jacobs also contends that the fraud claim should be dismissed as to the ‘714 Registration due to laches because WTIC’s delay in bringing the claim was unreasonable (the ‘714 Registration issued in 1989) and, with respect to the ‘473 Application, that the court lacks the statutory authority to cancel a pending trademark application.

Nordic Windpower (Nordic) is a Berkeley, California company that designs, manufactures and sells utility-scale wind turbines. 

Earlier this month Nordic announced that it had received a $16 million loan guarantee offer from the U.S. Department of Energy.  Nordic said it will use the government funds to expand its Idaho assembly plant.

Nordic’s turbines have a two-blade design rather than the more traditional three-blade rotor common in utility-scale wind.

A two-blade design reduces the cost associated with providing blades and simplifies assembly but also requires a different hub design because a two-blade turbine is less balanced and more prone to fatigue from that unbalance than the conventional three-blade turbine.

Teeter hubs, which are hinged to the turbine shaft, were developed for two-blade turbines, but they don’t hold up well in extreme wind conditions.

Nordic has developed flexible teeter hub technology so the rotor blades can flex at the hub to dissipate high winds before they can reach or damage the turbine drive train.  International Pub. No. WO 02/079647 (’647 Application) describes and claims Nordic’s flexible teeter hub assembly. 

The ‘647 Application is directed to a teeter hub (2) that allows some flexing while also better absorbing extreme torque.  Blades (1) are connected to the hub (2), and the hub is connected to the turbine shaft (3). 

The reaction arm (15) extends all they way through the hub (2) from the periphery adjacent the turbine shaft (3) to the opposite side of the hub.  The length of the reaction arm (15) allows the hub assembly to better absorb extreme torque caused by high winds.

The bearing (12), the reaction arm (15) and the spring elements (13) together form a hinge assembly.  When high winds blow, the hinge assembly allows the hub (2) to pivot slightly while the springs (13) counteract the teeter movement. 

The torque is absorbed with an even distribution on the bearing (12) and the springs (13) thus minimizing damage to the turbine.