29
Oct
By Tom Fisher
Further to our August 10 post, on October 21, 2009, ALJ Carl C. Charneski issued the public version of the Initial Determination (“ID”) (dated August 7, 2009) in Certain Variable Speed Wind Turbines and Components Thereof (Inv. No. 337-TA-641).

By way of background, the Complainant in this investigation is General Electric Co. (“GE”) and the Respondents are Mitsubishi Heavy Industries, Ltd. (“MHI”), Mitsubishi Heavy Industries America, Inc. (“MHIA”), and Mitsubishi Power System, Inc. (“MPSA”) (collectively, “Mitsubishi”).  On August 7, 2009, ALJ Charneski issued the ID in this investigation finding that a violation of Section 337 had occurred in the importation into the U.S., the sale for importation, and the sale within the U.S. after importation of certain variable speed wind turbines and components thereof.  According to the ID, ALJ Charneski held that Mitsubishi’s turbines infringe claim 121 of the asserted ‘039 patent, and claim 15 of the asserted ‘985 patent.  Additionally, while ALJ Charneski determined that Mitsubishi’s turbines infringe claims 5, 7, and 8 of the asserted ‘221 patent, he also determined that GE did not practice any claim of the asserted ‘221 patent, and therefore did not satisfy the domestic industry (technical prong) requirement for the ‘221 patent.

The three asserted patents involve wind turbines used to generate electricity.  GE accused two models of Mitsubishi MWT wind turbines of infringement.

The ‘039 Patent

The ‘039 patent relates generally to variable speed wind turbines, and more particularly to a power converter for converting wind energy into AC power and for controlling torque.  Only claim 121 of the ‘039 patent was asserted by GE.

Regarding claim construction, the meaning of four claim elements was disputed.  First, ALJ Charneski construed the term “induction generator” according to its plain meaning, which he interpreted to read on any multiphase induction generator and need not be limited to a squirrel cage induction generator, as Mitsubishi and the Commission Investigative Staff (“Staff”) argued, or either a squirrel cage or a doubly-fed induction generator (“DFIG”), as GE argued.  Second, ALJ Charneski construed the term “power converter” to mean a power converter that may be used in connection with the multiphase induction generator required in the preceding claim element.  Third, ALJ Charneski construed the term “inverter for supplying output electricity” to mean an inverter that (1) must supply output electricity, and (2) must have active switches, and not a line-side or grid-side inverter, as Mitsubishi argued.  Fourth, ALJ Charneski construed the term “inverter controller means” not as a means-plus-function claim, as Mitsubishi and the Staff argued, but rather as a piece of equipment that may be implemented in the form of a digital processor that is not restricted to the examples or algorithms contained in the preferred embodiment in the ‘039 specification, but that must control the active switches to supply electricity at a desired angle between voltage and current.

GE accused Mitsubishi’s MWT turbines of infringing claim 121 both literally and under the doctrine of equivalents.  The Staff agreed with Mitsubishi that the MWT turbines do not infringe claim 121 either literally of under the doctrine of equivalents.  ALJ Charneski found by a preponderance of the evidence that the MWT turbines practice each of the four disputed claim limitations literally, so he did not conduct an analysis under the doctrine of equivalents (but he opined that “based on the sparse analysis presented by GE on this issue, it is unclear whether infringement could be found under the doctrine of equivalents on a limitation-by-limitation basis.”).

ALJ Charneski further found by a preponderance of the evidence that GE satisfied both the economic and technical prongs of the domestic industry requirement with respect to the ‘039 patent, disagreeing with Mitsubishi and the Staff that the GE Turbine does not practice claim 121 literally.

Mitsubishi argued that the ‘039 patent was invalid on the grounds of lack of enablement, lack of adequate written description, and obviousness.  The Staff disagreed with Mitsubishi as to certain prior art raised in connection with alleged obviousness, and further argued that if claim 121 was construed to contain a means-plus-function element as the Staff contended, then the invalidity defenses need not be reached.  ALJ Charneski found that Mitsubishi did not establish any of its invalidity defenses by clear and convincing evidence.  Specifically, ALJ Charneski found that Mitsubishi’s lack of enablement argument rested on a faulty characterization of the testimony of GE’s expert, who did not, as Mitsubishi contended, testify that any novelty in claim 121 is found within the particular inverter control unit shown in Figure 13 of the ‘039 patent.  As to Mitsubishi’s written description argument, ALJ Charneski found that DFIGs and the use of inverters to control them were well known in the art, and thus the inventors were not required to discuss or illustrate a DFIG embodiment in order to inform a person of ordinary skill that the invention may be implemented with a DFIG.  With respect to obviousness, ALJ Charneski found that:  (1) the Arsudis dissertation does not teach a power factor control signal like that claimed in the ‘039 patent; (2) the cycloconverter taught by the Warneke article, unlike the power converter of claim 121, does not contain an inverter, nor does Warneke teach control to a desired angle between voltage and current or responsiveness to a power factor control signal as disclosed in the ‘039 patent; (3) the Mohan text discusses utility interfaces and electric locomotives in the context of a single-phase circuit rather than adapting its teachings to a multiphase induction generator, and discusses how to produce power only at a unity power factor instead of showing control to other desired angles between voltage and current, and does not disclose control in response to a power factor control signal as required by claim 121; and (4) the Ooi reference does not address considerations particular to wind turbines and how they connect to the grid, nor does it suggest the control of output electricity to a desired power factor angle in response to a power factor control signal as required by claim 121.

The ‘221 Patent

The ‘221 patent also relates to wind turbines.  Independent claim 5 and dependent claims 7 and 8 were asserted by GE.

Regarding claim construction, only the meaning of the “emergency unit” element of claim 5 was disputed, specifically the limitation that requires “releasing” the rotor current feed-in after the decoupling has taken place.  ALJ Charneski construed “emergency unit” to require releasing the rotor current feed-in as soon as the currents generated in the rotor windings by variation of the grid voltage amplitude triggering the decoupling are declined to a predetermined value.  Further, ALJ Charneski stated that the “predetermined value” is to be determined before operation of the emergency unit, and the value should be determined so as not to jeopardize the electrical components of the turbine.

GE accused Mitsubishi’s MWT turbines of infringing claims 5, 7, and 8 both literally and under the doctrine of equivalents.  The Staff agreed with Mitsubishi that the MWT turbines do not satisfy two limitations of independent claim 5, either literally of under the doctrine of equivalents:  (1) “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,” and (2) “releasing the rotor current feed-in after decoupling, when the currents generated in the rotor windings by variation of the grid voltage amplitude triggering the decoupling are declined to a predetermined value.”  ALJ Charneski found by a preponderance of the evidence that the MWT turbines meet all the limitations of claim 5, both literally and under the doctrine of equivalents.  ALJ Charneski also found that the MWT turbines infringed dependent claims 7 and 8.

Regarding domestic industry, ALJ Charneski found that GE did not satisfy the technical prong because the evidence failed to show that the GE Turbine practices the “release arrangement” limitation of claim 5, either literally or under the doctrine of equivalents.

With respect to validity, Mitsubishi argued that the asserted claims of the ‘221 patent were obvious in view of the prior art.  The Staff argued that Mitsubishi failed to show that the prior art discloses the “releasing arrangement” of claim 5, and failed to establish that the Kühn reference qualifies prior art.  ALJ Charneski found that:  (1) Kühn is not prior art to the ‘221 patent, in part because Mitsubishi failed to present a witness with personal knowledge of Kühn’s publication or presentation at a conference; (2) the JP-196 reference discloses a so-called chopper circuit, not a crowbar or other circuit suitable for use in the claimed invention of the ‘221 patent, and thus teaches away from the “releasing” limitation of claim 5; and (3) the Larsen reference likewise teaches away from claim 5 because it discloses a “series compensation device” that is not involved in power generation, but instead designed to inject voltage into a load during a grid voltage drop so that the voltage to the load stays steady, and the crowbar circuit of Larsen has nothing to do with rotor currents and is not designed to activate when the grid voltage drops.  Claims 7 and 8 were found not to be invalid for the same reasons as claim 5.

The ‘985 Patent

The ‘985 patent relates to wind turbine generators, particularly to dealing with low voltage events on the grid.  Only claim 15 of the ‘985 patent was asserted by GE.

Regarding claim construction, the meaning of two claim terms was disputed.  First, ALJ Charneski construed the term “uninterruptible power supply during a low voltage event” as not restricted to a power storage system, and requiring operation during a low voltage event, not for only a portion of the event.  Second, ALJ Charneski construed the term “shunt current from the inverter and generator rotor” as requiring the shunt circuit to be coupled with the input of the inverter and the convert controller, and that the current must be shunted from the inverter and generator rotor.

In its main brief, GE argued that Mitsubishi’s MWT turbines infringe claim 15 literally, and in its reply brief, it raised a doctrine of equivalents argument with respect to the “uninterruptible power supply” limitation.  Mitsubishi argued that its turbines do not have a circuit coupled to the input inverter to shunt current from the inverter and generator rotor.  The Staff argued that the original version of the MWT turbine infringed claim 15, but Mitsubishi’s later EPSS version of the MWT turbine did not.  ALJ Charneski found that both the original and EPSS versions practiced the “uninterruptible power supply limitation” literally, but that GE’s doctrine of equivalents argument was insufficiently supported.  ALJ Charneski further found that the MWT turbines practice the shunt limitation literally.

ALJ Charneski further found by a preponderance of the evidence that GE satisfied both the economic and technical prongs of the domestic industry requirement with respect to the ‘985 patent, disagreeing with Mitsubishi and the Staff that the GE Turbine does not practice claim 15.

Mitsubishi argued that claim 15 was invalid on the grounds of obviousness and failure to disclose best mode.  Mitsubishi also argued that the ‘985 patent was unenforceable due to inequitable conduct in failing to name an alleged inventor.  The Staff argued that claim 15 is not invalid, but is unenforceable.  Regarding obviousness, ALJ Charneski agreed with the Staff in finding that the Hofmann articles do not disclose a crowbar circuit responsive to a control signal from a CCU, a converter controller coupled to both the inverter and the circuit that shunts the current, or the required uninterruptible power supply.  Regarding best mode, ALJ Charneski agreed with the Staff and found that the specific circuit design disclosed in the ‘221 patent specification but not the ‘985 patent specification was not shown to be the best design for the invention in the ‘985 patent, specifically with respect to claim 15.  ALJ Charneski further found that Mitsubishi failed to establish by clear and convincing evidence that the ‘985 patent was unenforceable due to inequitable conduct.
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