Ex Parte 7,321,221 et al

Patent Trial and Appeal Board

Mar 31, 2014

95001272 (P.T.A.B. Mar. 31, 2014)

UNITED STATES PATENT AND TRADEMARKOFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
95/001,272 12/01/2009 7,321,221 1299600.00187US1 6771
23483 7590 04/01/2014
WILMERHALE/BOSTON
60 STATE STREET
BOSTON, MA 02109
EXAMINER
DEB, ANJAN K
ART UNIT PAPER NUMBER
3992
MAIL DATE DELIVERY MODE
04/01/2014 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
________________

MITSUBISHI HEAVY INDUSTRIES, LTD.
Requester and Respondent

v.

GENERAL ELECTRIC COMPANY
Patent Owner and Appellant

________________

Appeal 2014-000556
Reexamination Control 95/001,272
Patent 7,321,221 B2
Technology Center 3900
________________

Before JEFFREY B. ROBERTSON, DENISE M. POTHIER, and
JEREMY J. CURCURI, Administrative Patent Judges.

CURCURI, Administrative Patent Judge.

DECISION ON APPEAL
Patent Owner/General Electric Company appeals the Examiner’s
decision to reject claims 1-19, 21, 27-29, and 36-39. PO App. Br. 1. We
have jurisdiction under 35 U.S.C. §§ 134 and 315.
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Claims 21 and 37 are rejected under 35 U.S.C. § 112, ¶4, for not
further limiting the claims from which they depend. RAN1 37; Ans. 2.
Claims 21, 28, and 37-39 are rejected under 35 U.S.C. § 112, ¶2, for
indefiniteness. RAN 38-39; Ans. 2.
Claims 21 and 37-39 are rejected under 35 U.S.C. § 112, ¶1, for
lacking written description support or lacking an enabling disclosure. RAN
39-40; Ans. 2.
Claims 1-19, 21, 27-29, and 36-39 are rejected under 35 U.S.C. §
103(a) as obvious over Sakamoto (US 6,285,533 B1; issued Sep. 4, 2001),
E.ON (“Supplemental Network Connection Rules for Wind Energy Systems,
Additional Network and Organizational Rules for Network Connection of
Wind Energy Systems within the Regulation Zone of E.ON Netz GmbH,”
December 1, 2001), and Mikhail (US 6,420,795 B1; issued July 16, 2002).
RAN 41-66; Ans. 3.
Claims 1-19, 21, 27-29, and 36-39 are rejected under 35 U.S.C. §
103(a) as obvious over Ito (US 4,812,729; issued Mar. 14, 1989) and
Akhmatov (V. Akhmatov, “Variable-speed WindTurbines with Doubly-fed
Induction Generators Part II: Power System Stability,” Wind Engineering,
Vol. 26, No. 3, May 1, 2002). RAN 69-79; Ans. 3.

1 The Right of Appeal Notice (“RAN”) was mailed March 15, 2012; the
Examiner’s Answer, mailed February 5, 2013, incorporated the RAN by
reference. Claims 20, 22-26, and 30-35 have been canceled by an entry of
an amendment and are no longer rejected. Ans. 2.
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Claims 1-19, 21, 27-29, and 36-39 are rejected under 35 U.S.C. §
103(a) as obvious over Rebsdorf (US 6,566,764 B2; issued May 20, 2003),
E.ON, and Sakamoto. RAN 80-89; Ans. 3.
We affirm.

STATEMENT OF THE CASE
This proceeding arose from a request by Mitsubishi Heavy Industries,
Ltd. for an inter partes reexamination of U.S. Patent 7,321,221 B2, titled
“Method for Operating a Wind Power Plant and Method for Operating It”
(the ’221 patent). The ’221 patent describes a method of operating a wind
turbine including an induction generator with stator coils coupled to a
voltage grid, and rotor windings fed with rotor currents by a feed-in unit.
Abstract. Claim 1 is illustrative and reproduced below:
1. A method of operating a wind turbine, comprising:
driving a rotor of the wind turbine by feeding rotor
currents by a feed-in unit to rotor windings of an induction
generator, which comprises stator coils coupled to a voltage
grid; controlling the frequencies of the fed-in rotor currents
depending on the rotor rotation frequency;
electrically decoupling the feed-in unit from the rotor
windings in the case of predetermined variations of the grid
voltage amplitude by an emergency unit;
releasing the fed-in rotor currents after electrically
decoupling the feed-in unit using a release arrangement of the
emergency unit; and
when the rotor currents in the rotor windings by the
variation have declined to a predetermined value, resuming the
driving of the rotor of the wind turbine by feeding rotor currents
by the feed-in unit to rotor windings of the induction generator
after the decoupling caused by the variation of the grid voltage
amplitude.
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ANALYSIS
THE OBVIOUSNESS REJECTION OF CLAIMS 1-19, 21, 27-29, AND 36-39 OVER
SAKAMOTO, E.ON, AND MIKHAIL
We have reviewed the Examiner’s rejections in light of Patent
Owner’s arguments (PO App. Br. and PO Reb. Br.) and evidence (PO App.
Br. Evidence Appendix) that the Examiner has erred.
We disagree with Patent Owner’s contentions as to the obviousness
rejection of claims 1-19, 21, 27-29, and 36-39 over Sakamoto, E.ON, and
Mikhail.
We, therefore, sustain the obviousness rejection of claims 1-19, 21,
27-29, and 36-39 over Sakamoto, E.ON, and Mikhail.
We highlight the following arguments for emphasis.

Claims 1-3, 5-8, 10-12, 16-18, 21, 27, and 36-39
The Examiner finds Sakamoto, E.ON, and Mikhail teach all
limitations of claim 1. RAN 41-47. The Examiner finds
Sakamoto discloses electrically decoupling 95 (BLOCK THE
GATE FOR POWER INVERTER) (Fig. 6) the feed-in unit
from the rotor windings based on sensing excessive rotor
current by excess current sensor 46. Sak[a]moto’s
measurement of rotor current is broadly interpreted as an
indirect measurement of the variation of the grid voltage
amplitude.
RAN 44.
Patent Owner contends that Sakamoto does not mention rotor
currents, and does not decouple the feed-in unit from the rotor windings.
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PO App. Br. 7-8. Based on this position, Patent Owner presents the
following principal arguments:
(i) “There is no teaching in Sakamoto of any switches, much less
of switches in power inverter 39.” PO App. Br. 8.
(ii) “Sakamoto also does not teach that its inverter 39, or any
current from inverter 39, is ‘blocked.’” PO App. Br. 8.
(iii) “ ‘Blocking’ the power converter control signal from the
controller 41 does not ‘cut[] off the feed-in current from the inverter to the
rotor winding’ as asserted by the Examiner. All it does is cause power
inverter 39 to stop converting direct current from power rectifier 38 to
alternating current.” PO App. Br. 8; see also PO Reb. Br. 5-7.
(iv)
Again contrary to the Examiner’s apparent understanding,
Sakamoto’s “regenerative diodes” do not pass rotor currents
from the rotor to a DC link capacitor that, according to the
Third Party Requester, is located between power rectifier 38
and power inverter 39. The Examiner is correct that such
regenerative diodes pass current in only one direction. But in
Sakamoto that direction is clockwise (as shown in Fig. 1) to
dissipate fault current from generator-motor 35[.]
PO App. Br. 9.
(v) “But even if we were to accept the Examiner’s scenario (which
requires the regenerative diodes be reversed, the direct current capacitor to
be moved, and Sakamoto to lose its ability to deal with ‘fault currents’), that
hypothetical arrangement does not decouple Sakamoto’s ‘feed-in unit’ and
rotor windings.” PO App. Br. 11.
We agree with the Examiner and Requester that Sakamoto’s blocking
the gate for the power inverter (secondary current cutoff control 95, Fig. 6;
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power inverter 39 and power inverter control signal 44, Fig. 5) describes the
recited electrically decoupling the feed-in unit from the rotor windings.
We agree with the further elaboration by Third Party Requester and
adopt as our own Third Party Requester’s analysis: Sakamoto blocks the
gate for the power inverter.
This causes the inverter to cut off the excitation currents fed
into the rotor windings. (Ex. E [Sakamoto] at col. 5:2-6.)
“Cutting off” the excitation currents means that the inverter
ceases to feed the excitation current to the rotor windings from
the inverter. (Ex. S, Third [Dr. Ronald] Harley Decl. ¶ 7.)
In fact, Sakamoto expressly states that “activating” the
power inverter control signal 44 results in “conducting” the
excitation current from the inverter 39 to the rotor windings 40
and that “deactivating” the power inverter control signal results
in “cutting off the [excitation] current.” (Ex. E at col. 24:49-
53.) One of ordinary skill in the art would understand from
Sakamoto’s distinction between “conducting” and “cutting off
the current” that no excitation current is conducted by the
inverter 39 when the power inverter control signal 44 is
deactivated or blocked and that excitation current feed-in
resumes when the control signal 44 is activated. (Ex. S, Third
Harley Decl. ¶¶ 7, 17.) This is also consistent with Figure 6 of
Sakamoto, which states that the gate for the power inverter is
blocked. One of ordinary skill in the art would understand from
Figure 6 that, when blocked, the control signals 44 cannot reach
the gates of the switches within the power inverter so that they
remain open and cannot supply current to the rotor windings.
(Ex. P, Second [Dr. Ronald] Harley Decl. ¶¶ 9-12.)
3PR Resp. Br. 11.
We have considered the arguments (PO App. Br. and PO Reb. Br.)
and evidence (PO App. Br. Evidence Appendix) presented by Patent Owner,
including the declarations by Dr. James L. Kirtley, and we are not persuaded
of Examiner error.
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Contrary to Patent Owner’s argument (i), the evidence of record (3PR
Resp. Br. Evidence Appendix P, Second Harley Decl., ¶ 9) supports the
Examiner’s findings, and explains that “Sakamoto’s power inverter 39 could
have been a conventional inverter containing a diode bridge and switches
(typically IGBTs) wired in parallel with these diodes.” Further, as stated in
the Second Harley Declaration, “Sakamoto’s description of inverter 39 is
consistent with a conventional inverter when referring to blocking the power
inverter control signal 44 ([Sakamoto,] col. 5:4-5) and the gate of the
inverter 39 (Fig. 6 step 95) and when referring to the diodes of the inverter
(col. 26:18-19).” 3PR Resp. Br. Evidence Appendix P, Second Harley Decl.
¶ 9. Thus, Patent Owner’s argument that Sakamoto fails to disclose switches
is not persuasive.
Regarding Patent Owner’s arguments (ii) and (iii), the evidence of
record (3PR Resp. Br. Evidence Appendix P, Second Harley Decl. ¶ 9)
supports the Examiner’s findings, and explains that
Sakamoto’s use of the word “blocking” means that the switches
of the inverter 39 are left open when control signal 44 is
blocked, so that no current can pass through the switches…
Under normal operation, i.e., when not blocked, Sakamoto’s
control signal 44 controls the switches of the inverter in order to
control the frequency and magnitude of the “exciting” or “feed-
in” currents to be synchronized with the desired rotor speed.
Accordingly, Patent Owner’s argument that Sakamoto does not teach
blocking the inverter 39 is not persuasive in view of the Examiner’s findings
regarding the prior art considered in conjunction with the other evidence of
record.
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Contrary to Patent Owner’s argument (iv), the evidence of record
(3PR Resp. Br. Evidence Appendix P, Second Harley Decl. ¶ 11) supports
the Examiner’s findings, and explains that
[d]uring a grid fault, and when the switches in 39 are blocking
or open, Sakamoto teaches that regenerative diodes short-circuit
the rotor windings (i.e., the secondary circuit 40) of the
generator-motor 35. Sakamoto calls this a short circuit because,
when the diodes start conducting the reverse current they are
applying a rectified voltage (from the induced rotor voltage)
across the DC link capacitor. This voltage is larger than the
capacitor voltage at that moment and, for this difference in
voltage, the capacitor behaves like a short circuit because the
diodes are turning on to a low impedance. This is the well-
known behavior of capacitors as they charge and discharge in
DC circuits.
3PR Resp. Br. Evidence Appendix P, Second Harley Decl. ¶ 11.
We are, therefore, unpersuaded by Patent Owner’s argument in view
of the Examiner’s findings regarding the prior art considered in conjunction
with the other evidence of record including the Second Harley Declaration’s
explanation (Second Harley Decl. ¶ 11) that the regenerative diodes conduct
a reverse current.
Contrary to Patent Owner’s argument (v), the evidence of record (3PR
Resp. Br. Evidence Appendix P, Second Harley Decl. ¶ 13) supports the
Examiner’s findings, and explains that
[b]ecause the diodes in 39 form a rectifier bridge and are
reverse biased, together with the open switches in 39, they
block or cut off any exciting current flow from the positive rail
of the DC link to 40. This arrangement electrically decouples
the inverter switches that supply the feed-in current in their
normal, unblocked state, because they cannot conduct current
when blocked.
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3PR Resp. Br. Evidence Appendix P, Second Harley Decl. ¶ 13.
Thus, we disagree with Patent Owner that Sakamoto’s ‘feed-in unit’
and rotor windings are not decoupled because the open switches block or cut
off any exciting current flow from the positive rail of the DC link to 40; the
presence of the diodes does not preclude decoupling.
We, therefore, sustain the Examiner’s rejection of claim 1. Patent
Owner does not separately argue claims 2-3, 5-8, 10-12, 16-18, 21, 27, and
36-39 with particularity. Accordingly, we sustain the Examiner’s rejection
of these claims for the same reasons.

Claims 4, 9, 13-15, 19, 28, and 29
The Examiner finds Sakamoto, E.ON, and Mikhail teach all
limitations of claim 4. RAN 48. The Examiner finds “Sakamoto disclosed
electrically decoupling comprises short-circuiting 95 the rotor windings
(SHORT-CIRCUIT SECONDARY CIRCUIT) (Fig. 6).” RAN 48.
Patent Owner argues Sakamoto’s regenerative diodes short circuit the
fault current from the stator of generator-motor 35; Sakamoto may short
circuit the stator, but does not short circuit the rotor windings. PO App. Br.
12; see also PO Reb. Br. 4-5.
We are not persuaded of Examiner error.
Contrary to Patent Owner’s arguments, and as explained by Third
Party Requester,
Sakamoto refers to the rotor windings as the secondary circuit
40 and stator windings as the primary circuit. (Ex. P ¶ 8.)
Moreover, Sakamoto depicts the rotor windings as the smaller
of the concentric circles of the induction generator-motor 35
and explains that the rotor windings (secondary circuit) receives
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the excitation current. ([Sakamoto,] col. 25:14-17, “The
resulting alternating current is supplied to the secondary circuit
40 of the induction generator-motor 35, thereby operating the
induction generator motor 35 at variable speed.”)…
Accordingly, when Sakamoto teaches short-circuiting the
secondary circuit 40 (col. 26:15-19), Sakamoto is referring to
short-circuiting the rotor windings of the induction generator-
motor. (Ex. M [The First Dr. Ronald Harley Declaration] ¶ 59.)
3PR Resp. Br. 12-13.
Thus, we agree with the Examiner and Third Party Requester that
Sakamoto’s short-circuiting the secondary circuit (secondary current cutoff
control 95, Fig. 6; power inverter 39 and power inverter control signal 44,
Fig. 5) describes the recited short-circuiting the rotor windings because
Sakamoto’s secondary circuit includes the rotor winding and Sakamoto
short-circuits the secondary circuit.
We, therefore, sustain the Examiner’s rejection of claim 4. Patent
Owner does not separately argue claims 9, 13-15, 19, 28, and 29 with
particularity. Therefore, we sustain the Examiner’s rejection of these claims
for the same reasons.

THE INDEFINITENESS REJECTION OF CLAIMS 21, 28, AND 37-39
Claims 21 and 37-39
The Examiner finds
that grid faults are unpredictable by nature, so it is not possible
to predict with any reasonable certainty whether grid instability
will lasts longer than the time it takes to resume feed-in of the
excitation currents. Moreover, neither the claims nor the ’221
patent specification describe any basis for determining whether
grid “stabilization” or “stabilizing” has occurred.
RAN 38.
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Patent Owner argues “[d]ependent claims 21 and 37 specifically recite
a capability of the wind turbine generator and its release arrangement. The
concept of grid stabilization is well understood by those skilled in the art and
is described in the ’221 patent.” PO App. Br. 26; see also PO Reb. Br. 17.
Patent Owner further argues “[i]ndependent claims 38 and 39 state
specifically that the point in time at which driving is resumed by feeding
rotor currents occurs prior to the grid voltage amplitude stabilization. When
that happens may vary, but there is nothing indefinite about a claim that
requires a step to be taken before some event occurs.” PO App. Br. 26-27;
see also PR Reb. Br. 17.
We are not persuaded of Examiner error.
Claim 21 recites the step of resuming “before the grid voltage
amplitude has stabilized.” Claim 37 recites “the release arrangement is for
releasing the current feed-in of the rotor currents before the grid voltage
amplitude has stabilized.” Claim 38 recites “the resuming the driving of the
rotor of the wind turbine by feeding rotor currents by the feed-in unit to rotor
windings before the grid voltage amplitude stabilizes.” Claim 39 recites “a
release arrangement for 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 have declined to a
predetermined value and before the grid voltage amplitude stabilizes.”
Without any reasonable certainty as to the duration of the grid
instability, we agree that claims 21 and 37-39 are indefinite. Because of the
unpredictable nature of grid instability, one of ordinary skill in the art would
not have been able to ascertain the meets and bounds of claims 21 and 37-
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39. Owner asserts that the grid stability is well understood but provides
inadequate support for this assertion. PO App. Br. 26. Yet, arguments made
by counsel do not take the place of evidence in the record. We, therefore,
sustain the indefiniteness rejection of claims 21 and 37-39.

Claim 28
The Examiner finds “[c]laim 28 recites ‘the release element’ for
which there is no antecedent basis in claim 5.” RAN 38.
Patent Owner explains “[t]he supposed lack of antecedent basis
relative to claim 28 is corrected by the amendment filed with the petition
pursuant to 37 C.F.R. 1.182 / 1.183 removing the word ‘element’ and
replacing it with ‘arrangement’.” PO App. Br. 27.
The corrective amendment referred to by Patent Owner was entered
on January 23, 2013. Accordingly, we do not sustain the Examiner’s
indefiniteness rejection of claim 28.

THE REMAINING REJECTIONS
Review of alternative prior art bases for rejection to claims, which
have already been determined to be appropriately rejected over the prior art,
is discretionary. See, e.g., In re Gleave, 560 F.3d 1331, 1338 (Fed. Cir.
2009) (not reaching rejections based on obviousness when claims already
rejected as anticipated). We exercise our discretion and decline to reach the
merits of the remaining rejections over the prior art. We also exercise our
discretion and decline to reach the merits of the remaining rejections under
35 U.S.C. § 112 because claims 21 and 37-39 are indefinite.
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SECONDARY CONSIDERATIONS
Patent Owner argues and presents evidence regarding commercial
success, copying and long-felt need of the claimed invention in the ’221
patent. See PO App. Br. 4; PO App. Br. Evidence Appendix; PO Reb. Br. 3-
4.
Third Party Requester in response explains a nexus has not been
shown between claimed features and the secondary indicia. See 3PR Resp.
Br. 5-8.
We have given full consideration to Patent Owner’s arguments and
evidence of secondary considerations. We agree with Third Party Requester
that a nexus has not been show between the claimed features and the
secondary indicia. Patent Owner does not relate the secondary
considerations to the specific limitations of the claims. Thus, we agree with
the Examiner and Third Party Requester, and are not persuaded of Examiner
error.

ORDER
The Examiner’s decision rejecting claims 1-19, 21, 27-29, and 36-39
is affirmed.
Requests for extensions of time in this inter partes reexamination
proceeding are governed by 37 C.F.R. § 1.956. See 37 C.F.R. § 41.79.
In the event neither party files a request for rehearing within the time
provided in 37 C.F.R. § 41.79, and this decision becomes final and
appealable under 37 C.F.R. § 41.81, a party seeking judicial review must
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timely serve notice on the Director of the United States Patent and
Trademark Office. See 37 C.F.R. §§ 90.1 and 1.983.

AFFIRMED

Patent Owner:

WILMERHALE/BOSTON
60 State Street
Boston, MA 02109

Third Party Requester:

OBLON, SPIVAK, McCELLAND,
MAIER & NEUSTATDT, LLP
1940 Duke Street
Alexandria, VA 22314

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