Court Opinion

ID: 803756
Source: CourtListenerOpinion
Date Created: 2012-07-06 15:09:43+00
Date Added: 2024-06-11T18:00:09.614393
License: Public Domain

United States Court of Appeals
      for the Federal Circuit
              __________________________

         GENERAL ELECTRIC COMPANY,
                  Appellant,

                           v.
     INTERNATIONAL TRADE COMMISSION,
                 Appellee,

                          AND

    MITSUBISHI HEAVY INDUSTRIES, LTD.,
 AND MITSUBISHI POWER SYSTEMS AMERICAS,
                    INC.,
                 Intervenors.
              __________________________

                      2010-1223
              __________________________

   Appeal from the United States International Trade
Commission in Investigation No. 337-TA-641.
             ___________________________

                 Decided: July 6, 2012
              ___________________________

    WILLIAM F. LEE, Wilmer Cutler Pickering Hale and Dorr
LLP, of Boston, Massachusetts, for appellant. With him on
the brief were RICHARD W. O’NEILL, LOUIS W. TOMPROS, and
SARAH B. PETTY.
GENERAL ELECTRIC   v. ITC                                  2

    JAMES A. WORTH, Attorney, Office of General Counsel,
United States International Trade Commission, of Washing-
ton, DC, for appellee. With him on the brief were JAMES M.
LYONS, General Counsel, and WAYNE W. HERRINGTON,
Assistant General Counsel.

   DONALD R. DUNNER, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, of Washington, DC, for intervenors.
With him on the brief were THOMAS H. JENKINS, THOMAS W.
WINLAND, JEFFREY C. TOTTEN and TYLER M. AKAGI; and
ROGER D. TAYLOR, of Atlanta, Georgia.
              __________________________

 Before RADER, Chief Judge, NEWMAN, AND LINN, Circuit
                       Judges.
NEWMAN, Circuit Judge.

    The General Electric Company appeals the decision of
the United States International Trade Commission, holding
that certain variable speed wind turbines imported by
Mitsubishi Heavy Industries, Ltd. and Mitsubishi Power
Systems Americas, Inc. (together “Mitsubishi”) do not
violate section 337 of the Tariff Act, 19 U.S.C. §1337. 1 The
patents at issue were General Electric’s United States
Patents No. 7,321,221 (the ’221 patent), No. 5,083,039 (the
’039 patent), and No. 6,921,985 (the ’985 patent).

    1    In the Matter of Certain Variable Speed Wind Tur-
bines and Components Thereof, Inv. No. 337-TA-641, USITC
Pub. 4202 (Jan. 2010), 2010 WL 5176683, (Final Determina-
tion); In the Matter of Certain Variable Speed Wind Tur-
bines and Components Thereof, Inv. No. 337-TA-641, USITC
Pub. 4202 (Aug. 2009), 2010 WL 5176683, (Initial Determi-
nation).
3                                    GENERAL ELECTRIC   v. ITC

              THE COMMISSION PROCEEDINGS

    On General Electric’s complaint, the Commission con-
ducted an investigation and the Administrative Law Judge
held an evidentiary hearing on all of the issues raised by
General Electric as complainant, by Mitsubishi as respon-
dent, and by the Commission’s investigators. By Final
Initial Determination, including 126 pages of findings of fact
and conclusions of law, the ALJ held that section 337 is
violated by the imported Mitsubishi turbines. The ALJ
determined that the ’221 patent is not invalid by reason of
obviousness; that the ’039 patent is not invalid by reason of
obviousness, written description, or enablement; and that
the ’985 patent is not invalid by reason of obviousness or
best mode. The ALJ also determined that the three patents
are infringed by the imported Mitsubishi wind turbines, and
that the intent element of inequitable conduct as to the ’985
patent was not established. The ALJ also determined that
the domestic industry requirement is not met as to the ’221
patent, but is met as to the ’039 and ’985 patents.

    Each participant requested review by the full Commis-
sion of the ALJ’s adverse rulings. The Commission “no-
ticed” review of the Final Initial Determination except for
(1) the issue of importation and (2) the intent finding of
inequitable conduct. 2 The Commission received briefing
and argument on all of the other issues, and held by Final
Determination that the ’039 patent is not invalid by reason
of obviousness or written description, that the ’039 and ’221
patents are not infringed by the Mitsubishi turbines, and
that the domestic industry requirement is not met as to any

    2  In the Matter of Certain Variable Speed Wind Tur-
bines and Components Thereof; Notice of Commission De-
termination to Review a Final Initial Determination of the
Administrative Law Judge, 74 Fed. Reg. 52,975 (Oct. 15,
2009).
GENERAL ELECTRIC   v. ITC                                     4

of the patents. The Commission took no position on any
other issue in the Final Initial Determination, and held that
section 337 is not violated by the Mitsubishi imported
turbines. This appeal followed.

     The ’039 patent expired on February 1, 2011, and this
court dismissed that portion of the appeal as moot, vacating
the Commission’s rulings as to the ’039 patent. 3 We now
affirm the Commission’s ruling that the ’221 patent is not
infringed. We reverse the Commission’s determination of no
domestic industry as to the ’985 patent, and remand for
further proceedings with respect to the ’985 patent.

              VARIABLE SPEED WIND TURBINES

    Electric power is generated from energy sources such as
coal, natural gas, nuclear fission, flowing water, and wind,
whereby the energy causes the rotation of magnets or elec-
tromagnets in association with coils of wire, producing an
electric current. See the parties’ joint tutorial of the tech-
nology presented to the ALJ, Hr’g Tr. Apr. 29, 2009.

    The electric current generated by wind turbines is usu-
ally fed to a centralized power grid, where electricity from
various facilities is combined, stored, and distributed.
Although wind is an advantageous source of energy, wind
activity tends to be extremely irregular, whereas uniform
electric current of fixed frequency is required to be fed to the
power grid. This led to the development of variable speed
wind turbines, which convert the irregular product of wind
energy into the fixed-frequency alternating current (AC)
required by the power grid. The General Electric ’221 and
’985 patents are directed to structure and circuitry that
protect the turbine components from the effects of irregu-
    3  General Elec. Co. v. Int’l Trade Comm’n, No. 2010-
1223 (Fed. Cir. Jan. 19, 2011) (unpublished order).
5                                   GENERAL ELECTRIC   v. ITC

larities caused by emergency events such as lightning
strikes, downed power lines, short circuits, and the like.

     The products whose importation is charged with viola-
tion of section 337 are variable speed wind turbines desig-
nated as Mitsubishi models MWT 92 and MWT 95. As
products of the domestic industry, General Electric desig-
nated its models SLE, XLE, and SE. The Mitsubishi and
General Electric turbines have the structure and circuit
configuration called a “doubly-fed induction generator,”
illustrated as follows:

Gen. Elec. Br. 17 (from J.A. 2222). In operation, the wind
turns the blades and causes the shaft to rotate, thereby
spinning the rotor and producing a magnetic field in the
winding coils, generating electric current. To produce AC
electricity of uniform and fixed frequency, in doubly-fed
induction generators a second magnetic field is imposed by
current drawn from the grid and, by operations not here at
issue, the system produces electricity of the desired uniform
frequency. Testimony of Dr. Collins, Hr’g Tr. 46-48 (Apr. 29,
2009), J.A. 2746-48.
GENERAL ELECTRIC   v. ITC                                     6

                               I

                      THE ’221 PATENT

    The ’221 patent relates to protective circuitry for varia-
tions in grid supply voltage in doubly fed induction genera-
tor wind turbines. The patent explains that

    the problem arises that large voltage differences be-
    tween grid and stator coils occur on variations of the
    supply voltage amplitudes caused in the grid by,
    e.g., short circuits. These differences cause, in turn,
    a strong current rise in the stator coils directly cou-
    pled to the grid. These strong current rises in the
    stator coils are caused because the induction gen-
    erator is usually fully excited at the variation of the
    grid frequency amplitude and mechanical energy is
    permanently supplied by the rotor. The strong cur-
    rent rise occurring in the stator coils on variations
    of the supply voltage leads to high induction volt-
    ages in the rotor windings, which can, in turn, cause
    damages on the converters used for feeding the ro-
    tor current.

’221 patent, col.1 ll.45-57. The ’221 patent employs a protec-
tive circuit called a “crowbar circuit,” which decouples the
current feed-in unit from the rotor windings when large
current variations occur, thereby protecting the circuitry.
Both the imported Mitsubishi and the domestic General
Electric wind turbines employ a system of protective de-
coupling of the rotor windings from the feed-in converter,
but the turbines differ in the method by which operation is
restored. In the General Electric turbines recoupling of the
circuitry occurs when the emergency-induced elevation in
current has declined to a predetermined value as measured
7                                     GENERAL ELECTRIC   v. ITC

in the turbine, and in the Mitsubishi turbines recoupling
occurs after a pre-set period of time.

                  A. Claim Construction

    The issue of infringement of the ’221 patent was deter-
mined based on the Commission’s construction of the ’221
claims with respect to the method of restoring operation
after an emergency-induced decoupling. The claim con-
struction question is the meaning of the term “predeter-
mined value” in the ’221 patent claim 5 (emphases added):

    5. A wind turbine, comprising:
         a rotor with at least one rotor blade, the rotor
    being rotatably arranged with regard to a substan-
    tially horizontal rotor axis;
         an induction generator whose rotor windings
    are coupled to the rotor and whose stator coils can
    be coupled to a voltage grid;
         a feed-in unit for feeding currents into the rotor
    windings;
         a control unit for controlling the frequency of
    the fed-in currents depending on the rotor rotation
    frequency, and
         an emergency unit which can be operated to
    electrically decouple the feed-in unit from the rotor
    windings in case of variations of the grid voltage
    amplitude, wherein the emergency unit comprises a
    release arrangement for releasing the rotor current
    feed-in after decoupling, when the currents gener-
    ated in the rotor windings by variation of the grid
    voltage amplitude triggering the decoupling are de-
    clined to a predetermined value.

The Commission held that the claim’s release arrangement
“requires the wind turbine to measure current or an ade-
GENERAL ELECTRIC   v. ITC                                   8

quate proxy for current to determine whether the current
has declined to a level previously decided upon.” Final
Determination, at 26. The Commission held that a pre-set
period of time is not such a proxy for current.

    General Electric argues that the term “predetermined
value,” construed in light of the specification, includes not
only a value of current, but also a predetermined period of
time, for the ’221 patent states that turbine operation can be
resumed “under consideration of a predetermined time
constant.” ’221 patent, col.3 ll.5-6. General Electric points
out that the ’221 patent recognizes and recites time periods
for externally-caused fluctuations in current, and argues
that the Commission incorrectly construed the claims as
excluding a predetermined time constant from “predeter-
mined value.” General Electric cites several supporting
statements in the ’221 specification:

        Basically, resuming the feeding of rotor current
    can be accomplished under consideration of a prede-
    termined time constant. In view of an increase in
    plant safety, it has been shown particularly expedi-
    ent that when the rotor current is sensed as a two
    or three-phase signal or the rectified current is
    sensed as a single-phase signal and the current that
    was sensed drops to a pre-determined value, the
    feeding of the rotor current is resumed. Current
    transformers (e.g. current-compensated transform-
    ers) can be used for sensing the currents.
        . . . When the amplitude of the rotor current
    has dropped sufficiently after 100 to 200 msec [mil-
    liseconds], the feeding of the rotor current can be
    resumed on recurrence of the supply voltage within
    the framework of the method according to the in-
    vention.
9                                     GENERAL ELECTRIC    v. ITC

       . . . As is explained above, in this case the rotor
    and the starter current diminish within 50 to 150
    msec depending on the resistance.

Id. at col.3 ll.4-13, col.3 ll.37-40, col.3 ll.54-56. General
Electric, citing Honeywell International, Inc. v. ITT Indus-
tries, Inc., 452 F.3d 1312, 1318 (Fed. Cir. 2006), argues that
because the specification refers to a predetermined time
constant “within the framework of the method according to
the invention,” the passage of a fixed period of time is in-
cluded in the scope of the claims. The ALJ agreed with
General Electric’s position, and held that “[a] time constant,
in the form of a specific time range, may be considered when
determining that predetermined value.” Initial Determina-
tion, at 70.

    The full Commission did not agree with the ALJ. The
Commission found that the portion of the specification that
mentions a “predetermined time constant” is in the context
of an “increase in plant safety,” col.3 l.6, and that the speci-
fication teaches that measurement of current, not time,
increases safety. The Commission found that the specifica-
tion “presents the latter current-drop mode as an improve-
ment on the former amount-of-time mode.”                  Final
Determination, at 27. The ’221 specification’s only descrip-
tion of the operation of the invention shows recoupling upon
measurement of a predetermined value of current, not upon
passage of a pre-set period of time.

    We share the Commission’s view that the patentee de-
scribes the invention as the resumption of current feed after
the current is restored to the predetermined value, not after
a fixed period of time. The specification describes and
enables the deactivation of the crowbar circuit “[w]hen the
current drops afterwards to a predetermined value” of
current; there is no description or exemplification of re-
GENERAL ELECTRIC   v. ITC                                    10

sumption of operation by recoupling the rotor currents after
a pre-set period of time. The specification states:

        As is shown in FIG. 3, short-circuit element 60
   (‘crow bar’) can be realized as a B6 bridge. In this
   case, the dying out of the rectified rotor currents can
   be accomplished via a current transformer resistor
   62 in the B6 bridge. When the intermediate circuit
   voltage in converter 50 exceeds a predetermined
   value due to exceedingly high rotor currents, the
   crow bar formed as a B6 bridge is fired. Then, the
   same procedure as in the case of a short-circuit of
   the grid is executed. Should an exceedingly high
   current appear in the rotor due to a short-term un-
   dervoltage of the grid, the turbine really acts like in
   the case of a short-circuit of the grid. When the cur-
   rent drops afterwards to a predetermined value, the
   thyristors of the B6 bridge become blocked and the
   short-circuiting of the rotor windings 34 is ended.
   The feed-in of rotor currents is then resumed. Con-
   sequently, the thyristors form the release arrange-
   ment of the embodiment of the present invention.

’221 patent, col.5 ll.8-24 (emphases added). Figure 3, to
which this passage refers, shows the crowbar circuit 60
formed as a bridge that short-circuits and thereby decouples
the rotor windings 34 upon the occurrence of exceedingly
high rotor current. Figure 3, a detailed view of the circuit
diagram in patent Figure 1, shows the transformer resistor
62, the rotor-sided rotor converter 54, and stator coils 32:
11                                  GENERAL ELECTRIC   v. ITC

The specification explains that the crowbar circuit 60 is
deactivated, the bridge is blocked, and the rotor windings
are recoupled, when the current drops to the predetermined
value.

     No embodiment in the patent, no drawing, no circuitry,
shows recoupling solely after a predetermined period of
time. Although the specification shows that General Elec-
tric knew that various electrical disturbances for which this
protective circuitry is intended occur within a known dura-
tion, the ’221 invention as claimed is explicitly limited to
recoupling when the actual end of the specific disturbance
has been determined by measurement of when the current
has declined to a predetermined value. Although General
Electric recognized and described the usual duration of such
electrical disturbances, a possibly broader disclosure accom-
panied by an explicit narrow claim shows the inventor’s
selection of the narrow claim scope. See 35 U.S.C. §112 ¶2
(“The specification shall conclude with one or more claims
particularly pointing out and distinctly claiming the subject
matter which the applicant regards as his invention.”).
GENERAL ELECTRIC   v. ITC                                  12

     The Commission held that the ’221 claims are directed
to a predetermined value of current or a proxy for current.
The inclusion of a proxy for current comports with Linear
Technology Corp. v. International Trade Commission, 566
F.3d 1049, 1060 (Fed. Cir. 2009), which held that “monitor-
ing the current to the load” could be indirectly measured by
voltage, for “once voltage is known, one skilled in the art
would recognize that Ohm’s Law4 easily allows current to be
calculated, therefore monitoring current indirectly by moni-
toring voltage.” The Commission’s construction of “prede-
termined value” as a value of current or a proxy for current
“stays true to the claim language and most naturally aligns
with the patent’s description of the invention.” Phillips v.
AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc)
(quoting Renishaw PLC v. Marposs Societá per Azioni, 158
F.3d 1243, 1250 (Fed. Cir. 1998)). This claim construction is
affirmed.

                      B. Infringement

     For infringement, every element and limitation of a
claim of the patent must be found in the accused device,
literally or in accordance with the doctrine of equivalents.
It is not disputed that the Mitsubishi turbines do not meas-
ure current or voltage in determining when to resume the
feed-in connection after decoupling has occurred. The
record contains expert testimony on the question of whether
a pre-set time period in the Mitsubishi turbines is an ade-
quate proxy for current. The experts for both sides agreed

    4   Ohm’s Law is a principle of electrical circuits and is
represented by the equation I (current) = V (voltage) / R
(resistance). Thus, it states that the current through a
conductor between two points is directly proportional to the
voltage across the two points, and inversely proportional to
the resistance between them.” Linear Tech., 566 F.3d at
1059 n.4.
13                                   GENERAL ELECTRIC   v. ITC

that there is no predictable relationship between the dura-
tion of low-voltage events and the restoration of safe current
levels, because of the variety of factors that can affect such
events and their duration. Testimony of Dr. Toliyat, Hr’g
Tr. 1453:10-19 (May 15, 2009), J.A. 4168; Testimony of Dr.
Collins, Hr’g Tr. 978:12-22 (May 13, 2009), J.A. 3645. The
experts’ testimony supports the Commission’s finding that a
predetermined value of time “cannot serve as an adequate
proxy for current because the relationship between the two
cannot be guaranteed.” Final Determination, at 27. We
affirm the Commission’s finding that the Mitsubishi tur-
bine, whereby recoupling occurs after a pre-set period of
time, does not literally infringe the ’221 claims.

    General Electric argued that even if there is not literal
infringement, the doctrine of equivalents applies because
the system in the ’221 patent and the Mitsubishi system
perform substantially the same function in substantially the
same way to achieve the same result, whether recoupling is
measured by current drop or by the passage of time. See
Voda v. Cordis Corp., 536 F.3d 1311, 1326 (Fed. Cir. 2008)
(summarizing the criteria of infringement based on equiva-
lency). The Commission found that a system that measures
when the specific emergency event has actually ended is not
substantially the same as a system that applies the same
time period to all emergency events. This finding was
supported by substantial evidence in the form of the experts’
testimony with respect to the technological facts. The
Commission’s determination that the Mitsubishi turbines do
not infringe the ’221 patent under the doctrine of equiva-
lents is affirmed.

                   C. Domestic Industry

    In view of our affirmance of noninfringement of the ’221
patent, we affirm that section 337 is not violated based on
GENERAL ELECTRIC   v. ITC                                    14

the ’221 patent. Although the Commission also ruled that
General Electric’s turbines do not now practice the ’221
invention and therefore do not meet the domestic industry
requirement as to this patent, we do not reach that aspect,
and vacate the Commission’s ruling thereon.

                              II

                      THE ’985 PATENT

    The ’985 patent is directed to wind turbine circuitry that
provides a stable output of electricity to the grid during low
voltage events. The Commission construed the ’985 patent
claim 15, the only claim at issue, in a manner that excluded
the General Electric turbines from the scope of the claim,
and on this claim construction the Commission held that
there is no domestic industry as to the ’985 patent. The
domestic industry requirement of the Tariff Act is set forth
in 19 U.S.C. §1337(a), subsections (2) and (3):

    §1337(a)(2) Subparagraphs (B), (C), (D), and (E) of
    paragraph (1) [concerning violations of section 337]
    apply only if an industry in the United States, relat-
    ing to the articles protected by the patent, copy-
    right, trademark, mask work, or design concerned,
    exists or is in the process of being established.

    (a)(3) For purposes of paragraph (2), an industry in
    the United States shall be considered to exist if
    there is in the United States, with respect to the ar-
    ticles protected by the patent, copyright, trademark,
    mask work or design concerned—

           (A) significant investment in plant and
           equipment;
15                                     GENERAL ELECTRIC   v. ITC

            (B) significant employment of labor or
            capital; or

            (C) substantial investment in its exploi-
            tation, including engineering, research
            and development, or licensing.

    The ’985 patent, entitled “Low Voltage Ride Through for
Wind Turbine Generators,” is directed to wind turbine
structure and circuitry that provide “ride through” stabiliza-
tion in periods of voltage fluctuation. The ’985 specification
describes low voltage ride through as providing one or more
of the following responses to voltage fluctuation:

     1) to remain synchronized to the power grid during
     severe voltage fluctuations, 2) to maintain function-
     ing of the blade pitch system in spite of lack of volt-
     age at the generator terminals, 3) to protect the
     power converter and generator from high voltages
     and currents during the voltage fluctuation, and 4)
     to temporarily shut down non-vital sub-systems
     that could be damaged by exposure to low voltages
     or could be tripped by either circuit breaker action
     or fuse operation.

’985 patent, col.2 ll.26-34. Ride through in the ’985 patent is
achieved by circuitry that monitors voltage and provides
supplemental power from an uninterruptible power supply
when the system signals the need for ride through, and
thereby protects the power converter and generator during
voltage fluctuations while preserving the turbine’s connec-
tion with the power grid.

    The Commission construed the ’985 patent claim 15
with attention to the aspect that is disputed in application
GENERAL ELECTRIC   v. ITC                                  16

to the General Electric turbines (emphasis added to the
aspect of concern):

    15. A wind turbine generator comprising:
        a generator;
        a power converter coupled with the generator,
    the power converter having an inverter coupled to
    receive power from the generator, a converter con-
    troller coupled with the inverter to monitor a cur-
    rent flow in the inverter wherein the converter
    controller is coupled to receive power from an unin-
    terruptible power supply during a low voltage event,
    and a circuit coupled with the input of the inverter
    and with the converter controller to shunt current
    from the inverter and generator rotor in response to
    a control signal from the converter controller.

Patent Figure 4 is “a block diagram of one embodiment of a
power converter having functionality to respond to a low
voltage event.” Id. at col.4 ll.44-46: 5

    5   This drawing as shown in the briefs is from the pat-
ent application, for it was agreed that Figure 4 as printed in
the ’985 patent inadvertently omitted the line connecting
Crowbar Circuit 440 to the Rotor Side of the Inverters.
17                                   GENERAL ELECTRIC   v. ITC

Figure 4 shows back-to-back inverters as part of the power
converter; the inverters receive power as needed during a
low voltage event “to keep the wind turbine generator
connected to and synchronized with the power grid.” ’985
patent, col.6 ll.27-29. The specification describes the con-
nections and functions of the components, including the
following:

          Inverter 410 is coupled with the generator (not
     illustrated in FIG. 4) and to inverter 420 which is
     coupled with the power grid. Crowbar circuit 440 is
     coupled with the output of the generator rotor.
     Converter controller 430 is coupled to receive data
GENERAL ELECTRIC     v. ITC                                 18

    indicating the current flowing in inverter 410 and to
    control crowbar circuit 440. In one embodiment,
    converter controller 430 selectively activates and
    deactivates crowbar circuit 440 to maintain the cur-
    rent in inverter 410 within an acceptable range.
        Crowbar circuits are known in the art and any
    appropriate (e.g., a circuit having sufficient power
    ratings) crowbar circuit can be used. In general,
    crowbar circuit 440 operates to shunt current from
    the generator rotor and inverter 410 and maintain
    inverter currents within safe levels. Thus, during
    normal operation crowbar circuit 440 is inactive.
    During a low voltage event converter controller 430
    selectively activates crowbar circuit 440 to maintain
    current levels in a safe range. Thus, crowbar circuit
    440 and converter controller 430 are part of a sys-
    tem that allows a wind turbine generator to ride
    through low voltage events and remain synchro-
    nized to the power grid.

Id. at col.4 l.50 to col.5 l.3.

    The issue of claim construction was whether claim 15
requires that the circuit that shunts current on signal from
the converter controller is located entirely outside of the
inverter. The Commission held that the shunt circuit must
be separate from the inverter, for otherwise the circuit could
not shunt current from the inverter, as claim 15 states. On
this construction, the Commission ruled that “[General
Electric’s] shunt circuit does not shunt current from the
inverter because it is within the inverter.” Final Determina-
tion, at 41-42. The ALJ had reached a different conclusion,
holding that “whether a particular shunting circuit located
within the inverter (as opposed to outside it) meets the
claim limitation will depend upon whether it is found to be
‘coupled with the input of the inverter and the converter
19                                    GENERAL ELECTRIC   v. ITC

controller,’ as required by the claim.” Initial Determination,
at 98. The ALJ held that the claim does not contain the
additional requirement that the shunt circuit is located
entirely outside of the inverter.

    The specification, in describing how the circuit shunts
current from the generator rotor and the inverter, and
describing the connections of the components, does not
require that the components are entirely separate. Provid-
ing “a protective circuit that maintains currents within an
allowable range,” col.4 ll.35-36, does not require that the
inverter and shunt circuits are entirely separate. Nor do
the words of claim 15 “coupled with the input of the inverter
and with the converter controller,” connote physical separa-
tion of the shunt circuit from the inverter.

     The Commission apparently viewed the claim clause
“shunt current from the inverter and generator rotor” in
isolation from its context as “a circuit coupled with the input
of the inverter and with the converter controller.” However,
the function of the shunt circuit does not depend on whether
the shunt circuit is entirely outside of the inverter, and the
’985 specification does not require separation of the inverter
and the shunt circuit in order for that circuit to be coupled
with the input of the inverter and with the converter con-
troller; rather, the term “coupled with” indicates a connec-
tion. See Johnson Worldwide Assocs., Inc. v. Zebco Corp.,
175 F.3d 985, 992 (Fed. Cir. 1999) (“‘[C]oupled’ generically
describes a connection, and does not require a mechanical or
physical coupling.”).

    A similar argument was rejected in NTP, Inc. v. Re-
search in Motion, Ltd., 418 F.3d 1282 (Fed. Cir. 2005),
where some of the claims recited a receiver “connected to” or
“coupled to” a processor or that the receiver “transfers”
information to the processor. The accused infringer in NTP
GENERAL ELECTRIC   v. ITC                                 20

had argued that “connected to,” “coupled to,” and “transfer
from” each requires the receiver and the processor to be
separate, but the court concluded that “the two components
could be connected, joined, or linked together by wires or
other electrical conductors and still be located in the same
housing or even on the same circuit board.” 418 F.3d at
1310-11. The court also held that the function that informa-
tion is transferred between two entities does not require
physical separation of the entities. Id. at 1310. NTP does
not support the Commission’s ruling that the word “from”
requires physical separation of the shunt circuit and the
inverter.

    We conclude that claim 15 requires that the circuit is
coupled with the input of the inverter and the converter
controller, whereby the current is shunted from the inverter
and the rotor; this requirement does not limit the placement
of the shunting circuitry to a location entirely external to
the inverter. As in Linear Technology, “there is nothing in
the claim language or specification that supports narrowly
construing the terms to require a specific structural re-
quirement or entirely distinct [circuits]. Rather, the [cir-
cuits] must only perform their stated functions.” 566 F.3d
at 1055. 6

    Mitsubishi also argues that the General Electric tur-
bines embody a modification of the circuitry system in the
’985 patent, and that this modification is separately pat-

    6   Mitsubishi submitted a letter in accordance with
Fed. R. App. P. 28(j), arguing that General Electric stated a
position before the PTO during the ongoing reexamination
of the ’985 patent that contradicts its arguments here.
General Electric responds that its argument distinguishing
a certain reference does not conflict with its position here.
On the information before us, the reexamination arguments
do not affect our conclusion.
21                                   GENERAL ELECTRIC   v. ITC

ented in General Electric’s U.S. Patent No. 7,239,036.
Mitsubishi states that if General Electric’s turbines practice
the subject matter claimed in a separate patent, they cannot
practice the invention of the ’985 patent. That is not cor-
rect, for a separately patented invention may indeed be
within the scope of the claims of a dominating patent. See
Hoechst Celanese Corp. v. BP Chems. Ltd., 78 F.3d 1575,
1582 (Fed. Cir. 1996) (“The fact of separate patentability
presents no legal or evidentiary presumption of nonin-
fringement . . . .”); Atlas Powder Co. v. E.I. du Pont De
Nemours & Co., 750 F.2d 1569, 1580 (Fed. Cir. 1984) (an
improvement in a step of a patented method, even if sepa-
rately patentable, may not avoid infringement). The scope
of the ’985 patent is determined on its own terms, independ-
ent of whether other aspects or modifications of the technol-
ogy are separately patented. The domestic industry
requirement is not negated if the technology as employed in
the domestic industry has been modified from its form when
the patent was obtained.

     We conclude that claim 15, correctly construed, covers
the domestic industry turbines. The Commission erred in
determining that General Electric does not meet the domes-
tic industry requirement with respect to the ’985 patent.
That ruling is reversed. See Osram GmbH v. Int’l Trade
Comm’n, 505 F.3d 1351, 1359 (Fed. Cir. 2007) (reversing
finding of no domestic industry, on corrected claim construc-
tion).

                         SUMMARY

     The ruling that Mitsubishi’s turbines do not violate sec-
tion 337 because they do not infringe the ’221 patent is
affirmed. The ruling that the domestic industry require-
ment is not met as to the ’221 patent is vacated as moot.
The ruling that there is no domestic industry corresponding
GENERAL ELECTRIC   v. ITC                                22

to the ’985 patent is reversed, and the case is remanded for
further proceedings with respect to the ’985 patent.

     AFFIRMED IN PART, VACATED IN PART,
      REVERSED IN PART, and REMANDED