Enercon GmbH v. International Trade Com'n

• Decision Date: 12 August 1998
• Docket Number: No. 97-1554,97-1554
• Citation: 151 F.3d 1376,47 USPQ2d 1725
• Parties: ENERCON GmbH and The New World Power Corporation, Appellants, v. INTERNATIONAL TRADE COMMISSION, Appellee, and Zond Energy Systems, Incorporated, Intervenor. Federal Circuit
• Court: U.S. Court of Appeals — Federal Circuit

Page 1376

151 F.3d 1376

47 U.S.P.Q.2d 1725

ENERCON GmbH and The New World Power Corporation, Appellants, v. INTERNATIONAL TRADE COMMISSION, Appellee and Zond Energy Systems, Incorporated, Intervenor.

No. 97-1554.

United States Court of Appeals,Federal Circuit.

Aug. 12, 1998.

Mary Helen Sears, The M.H. Sears Law Firm Chartered, Washington, DC, argued, for appellants. With her on the brief was Thomas S. Hahn. Of counsel was Howard E. Susman, Hillyer & Irwin, San Diego, CA.

Andrea C. Casson, Attorney-Advisor, Office of the General Counsel, U.S. International Trade Commission, Washington, DC, argued, for appellee. With her on the brief were Lyn M. Schlitt, General Counsel, James A. Toupin, Deputy General Counsel, and John A. Wasleff, Attorney.

Joel M. Freed, Howrey & Simon, Washington, DC, argued, for intervenor. With him on the brief were Therese K. Francese and Cecil E. Key, Jr. Also on the brief was William J. Griffin, Nixon & Vanderhye P.C., Arlington, VA.

Before NEWMAN, Circuit Judge, SMITH, Senior Circuit Judge, and GAJARSA, Circuit Judge.

GAJARSA, Circuit Judge.

This appeal relates to an investigation initiated by the United States International Trade Commission (ITC) under section 337 of the Tariff Act of 1930 as amended, 19 U.S.C. § 1337 (1994), based on a complaint filed by Kenetech Windpower, Inc. (Kenetech). Kenetech's complaint before the ITC alleged that Enercon GmbH (Enercon) and New World Power Corp. (NWP) planned to import into the United States certain variable wind turbines that infringed Kenetech's U.S. Patent No. 5,083,039 (the '039 patent). On August 30, 1996, the administrative law judge made an initial determination that Enercon had violated section 337 by selling for importation variable wind turbines that infringed claim 131 of the '039 patent and issued an order excluding Enercon's variable wind turbines from entry into the United States until the expiration of the '039 patent. The initial determination and exclusion order became final on October 28, 1996. Enercon appeals from the final exclusion order, Inv. No. 337-TA-376, entitled Certain Variable Speed Wind Turbines and Components Thereof, ¹ challenging the ITC's determination that it had jurisdiction in this case. Enercon also appeals certain aspects of the ITC's construction of claim 131 of the '039 patent. Because the ITC did not err in its determination that it had jurisdiction under section 337 and that Enercon's wind turbines infringed the '039 patent, we affirm the determination of the ITC.

BACKGROUND

A. The Technology

The '039 patent concerns a method of converting wind power into electrical power usable by an electric utility company. A wind turbine converts wind energy to electrical energy by using a wind-driven turbine in combination with an alternating current (AC) induction generator. As the wind turns the blades of the turbine, the rotor of the AC induction generator is activated, thereby generating electricity. In a variable speed wind turbine, the frequency of the generated power waveform depends upon the wind speed. The stronger the wind, the faster the turbine blades turn, and the greater the frequency of the generated power waveform. In North America, electrical utilities must deliver power to their customers at a standard constant frequency of 60 Hz. Therefore, the frequency of the power generated by the variable speed wind turbine must be continually adjusted to match this standard in order for the turbine to be able to contribute electrical power to the utility power grid. In addition, the converter must also closely match the "phase" of the utility power. The "phase" of a waveform refers to the points in time at which the sinusoidal wave reaches its positive and negative peaks. Even if the frequencies of the generated power and the utility power are equal, maximum power will not be delivered to the utility grid unless the phases also match. Essentially, the peaks and valleys must be matched so that the generated power constructively adds to the utility power at all times.

If the waveforms for both the voltage and current are in phase with one another, all of the power delivered by the generator is composed of "real" or usable power. If the voltage and current waveforms are out of phase with one another, a portion of the overall power consists of "reactive" power depending upon the degree to which the waveforms are out of phase. The degree to which the waveforms are out of phase is referred to as the "power factor angle" and is commonly denoted by the Greek letter phi ( ).

Utility companies generally attempt to deliver power that is completely in phase in order to maximize the real power available to their customers. However, inductive loads on a utility power grid can sometimes pull the current waveform out of phase with the voltage waveform. It is therefore desirable to "pre-correct" this distortion by providing a waveform that either leads or lags the waveform on the utility grid in order to counteract this effect. By changing the power factor angle phi, it is possible to both match the phase of the utility grid and to also adjust the amount of real and reactive power in the system to counteract the effect of inductive loads.

The '039 patent was issued on February 1, 1991. Claim 131 of the '039 patent, the only claim at issue in this appeal, is directed to a method for controlling the AC power output from a wind turbine to achieve a preselected power factor angle that is compatible with that of an electric utility grid. Claim 131 reads as follows:

A method for converting electricity generated by a variable speed wind turbine into fixed frequency output electricity, wherein the wind turbine includes a generator and means for supplying generated electricity to [a] power converter that includes a switched inverter supplying the output electricity, the method comprising the steps of:

forming a reference waveform;

rotating the reference waveform by a selected power factor angle to yield a template waveform;

using the template waveform to define desired output currents; and

controlling the switched inverter to produce output currents corresponding to the desired output currents.

According to the written description of the '039 patent, the variable frequency AC produced by the generator is converted to fixed frequency AC by using a power converter that includes active rectifiers for first converting the variable frequency AC to DC. The power converter also includes a switched inverter for converting DC back to AC. An inverter control unit further controls the switched inverter to supply power to the utility power grid with an adjustable phase. The power factor angle is adjusted so that the current supplied by the generator system is in phase with the voltage on the utility lines. Alternatively, the phase of the current supplied by the generator may be adjusted to lead the voltage in the utility lines in order to compensate for inductive loads at other points in the utility grid.

Claim 131 primarily concerns the manipulation of the current and voltage waveforms output from the power converter. The written description explains that the invention first forms a reference waveform by sampling the waveform on the grid. The claimed invention then rotates this waveform by a preselected power factor angle to generate a "template" or "model" waveform. The claimed invention then uses the switched inverter to control the output waveform from the power converter to match the template waveform as closely as possible.

B. The ITC's Jurisdiction Under Section 337

Section 337 lists the requirements for the ITC's jurisdiction. In particular, section 337 requires an "importation" or a "sale for importation" before the ITC may exercise jurisdiction over any accused goods. The ITC found a long and well established course of conduct between Enercon and NWP that demonstrated that there had been a contract for sale of Enercon's model E-40 variable wind turbines to NWP for importation into the United States, thereby bringing the turbines within its jurisdiction under section 337.

In 1993, NWP wrote to Enercon to request a price quote for a specific number of model E-40 variable wind turbines in connection with a project planned in the state of Washington. Enercon responded on August 18, 1993 with a written offer to sell NWP the E-40 wind turbines at a specific price per turbine, to be delivered on the west coast of the United States. The offer stated that it would remain open until March 31, 1994 and was signed by several of Enercon's officers. The ITC found that while this particular offer was not accepted, it did establish a set price per turbine when sold in the stated quantity. Following several meetings between Enercon and NWP, Enercon sent NWP a letter on February 15, 1994 stating that "[w]e once again would like to point out that we will be prepared to fulfill your requirements starting in 1995...."

On February 28, 1994, NWP submitted a bid on a project for Texas Utilities (TU) in Big Spring, Texas. In the bid, NWP stated an intention to use Enercon's E-40 variable wind turbines. In the ensuing months there were several meetings between NWP and Enercon, ostensibly to discuss the E-40 turbines and their use in the Big Spring project. On June 1, 1994, Enercon's U.S. affiliate reported in a faxed memorandum that the entire Big Spring project would likely be awarded to NWP and that Enercon needed to deliver the turbines. On June 3, 1994, an internal Enercon memorandum reported that the Big Spring project was indeed awarded to NWP and that Enercon was listed as providing the turbines for the project.

In September, 1994, NWP signed an energy purchase agreement with TU, the sponsor of the Big Springs project. The agreement specified that all wind turbines would be Enercon's model E-40 turbines. Near the end of 1994, Enercon investigated the cost involved in shipping the E-40 turbines from Germany to Big...