Ex Parte Luedtke

Patent Trial and Appeal Board

Oct 3, 2017

13607008 (P.T.A.B. Oct. 3, 2017)

United States Patent and Trademark Office
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.
13/607,008 09/07/2012 Daniel Luedtke 83257449 2377
28395 7590 10/05/2017
RROOKS KTTSHMAN P C /FfTET
EXAMINER
1000 TOWN CENTER DHAKAL, BICKEY
22ND FLOOR
SOUTHFIELD, MI 48075-1238 ART UNIT PAPER NUMBER
2837
NOTIFICATION DATE DELIVERY MODE
10/05/2017 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
docketing @brookskushman. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte DANIEL LUEDTKE
Appeal 2017-002454
Application 13/607,0081
Technology Center 2800
Before ROMULO H. DELMENDO, KAREN M. HASTINGS, and
JAMES C. HOUSEL, Administrative Patent Judges.
PER CURIAM.
DECISION ON APPEAL
The Appellant appeals under 35 U.S.C. § 134(a) from the Primary
Examiner’s final decision to reject claims 1, 2, 5—8, 11—13, 17, 20, and 21.2
We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.
1 The Applicant (hereinafter “Appellant”) states that the real party in interest
is “FORD GLOBAL TECHNOLOGIES, LLC” (Appeal Brief filed on
February 16, 2016, hereinafter “Appeal Br.,” 2).
2 Appeal Br. 4—5; Reply Brief filed on December 1, 2016, hereinafter “Reply
Br.,” 1—2; Final Office Action (notice emailed on September 15, 2015),
hereinafter “Final Act.,” 2—11; Examiner’s Answer (notice emailed on
November 3, 2016), hereinafter “Ans.,” 2—5.
Appeal 2017-002454
Application 13/607,008
BACKGROUND
The subject matter on appeal relates to a vehicle (e.g., an electric or
hybrid electric vehicle) comprising an electric machine configured with at
least one controller issuing torque commands with the use of a voltage bus.
Specification filed September 7, 2012, hereinafter “Spec.,” H 1, 3, 7. The
Appellant discloses that a controller can be used to control the torque
generated by an electric motor and can determine a maximum torque
capability threshold for the motor via a multi-dimensional look-up table. Id.
122. However, according to the Appellant, this can lead to errors and
clipping of the maximum torque capability to a lower value when the input
variables (e.g., rotor speed and bus voltage) fall between values included in
the look-up table, which causes underutilization of the machine’s capability.
Id. 22—23, 26; Drawings, Fig. 7.
In view of this, the Appellant discloses the use of normalized speed
(i.e., the ratio of rotor speed to bus voltage) as a single independent variable
to be input into a look-up table to determine the maximum torque capability.
Id. 1121, 24. The Appellant discloses that using this ratio permits the
determination of a constant torque value (i.e., a linear torque behavior)
because rotor speed and bus voltage increase proportionally. Spec. H 26—
27; Fig. 7. The Appellant discloses that this permits a system to deliver
torque closer to a torque requested by a driver. Id. H 18, 27.
Representative claim 1 is reproduced from page 7 of the Appeal Brief
(Claims Appendix) (emphasis added), as follows:
1. A vehicle comprising:
an electric machine;
a bus; and
at least one controller configured to, in response to torque
requests that exceed a torque capability threshold value of the
2
Appeal 2017-002454
Application 13/607,008
electric machine retrieved from a single independent variable
look-up table as a function of a normalized speed, issue torque
commands based on the normalized speed of the electric machine
by dividing a rotor speed by a voltage on the bus.
REJECTIONS ON APPEAL
The Examiner rejected the claims as follows (Final. Act. 2—11):
I. Claims 1, 5, 7, 11, 13, 17, 20, and 21 under pre-AIA 35
U.S.C. § 103(a) as unpatentable over Chen et al.3
(hereinafter “Chen”) in view of Cheng et al.4 (hereinafter
“Cheng”); and
II. Claims 2, 6, 8, and 12 under pre-AIA 35 U.S.C. § 103(a)
over Chen and Cheng and further in view of Aoki.5
DISCUSSION
The Examiner finds Chen discloses a vehicle comprising, among other
things, an electric machine, a bus, and at least one controller configured to
determine a torque capability threshold value IqMax. Final Act. 2—3. The
Examiner determines equation 12 of Chen could be written as
“square(2/pi*Lq*wr/Vdc),” which includes the normalized speed (wr/Vdc)
recited in claim 1. Id. at 3. The Examiner finds Chen does not disclose the
use of a single independent variable look-up table, as recited in claim 1. Id.
The Examiner finds Cheng discloses determining a torque capability
threshold for an electric machine via a single independent variable. Id.
3 US 2004/0036434 Al, published on February 26, 2004.
4 US 7,586,286 B2, issued September 8, 2009.
5 US 2011/0248719 Al, published on October 13, 2011.
3
Appeal 2017-002454
Application 13/607,008
Specifically, the Examiner finds Cheng discloses “[a]s noted in equation (7),
. . .the ellipses are only parameter functions of the flux linkage.” Id. (citing
Cheng 8:15—50). The Examiner finds that flux linkage is a ratio of motor
speed and DC bus voltage and the flux linkage can be written as
“2/(pi*(wr/Vdc)),” which the Examiner finds to be the normalized speed
recited in claim 1. Id. The Examiner concludes it would have been obvious
to modify Chen in view of Cheng’s teachings “in order to control the motor
using a feedforward current while using MTPA [sic, MTPV (maximum
torque per voltage)] and PTPA [peak torque per ampere] curves (See
Cheng’s column 8, lines 30-50)”. Id. at 4.
The Appellant contends “Cheng teaches that several curves in the Id,
Iq plane are a function of a single independent variable, y” but that “IqMax is
a scalar, not a curve in the Id, Iq plane.” Appeal Br. 5. More specifically, the
Appellant asserts the teachings of Cheng relating to a single independent
variable concerns an equation defining an ellipse, which is distinct from a
torque capability threshold value. Reply Br. 2. In view of this, the
Appellant argues there would have been a lack of reason to modify Chen in
view of Cheng’s teachings. Appeal Br. 5; Reply Br. 2.
The Appellant’s arguments are persuasive. Cheng discloses a
situation in which all motor parameters in equation (7) are fixed. Cheng
8:46-49. However, equation (7) of Cheng is directed to a voltage ellipse
equation. Id. at 7:46—54. Although the voltage ellipse equation of Cheng
appears to relate to the voltage limit ellipse equation (12) disclosed by
Chen,6 neither equation provides a torque capability threshold value as
6 Chen 173.
4
Appeal 2017-002454
Application 13/607,008
required by claim 1. This is demonstrated by the Examiner’s finding that
Chen discloses a torque capability threshold value IqMax,7 which is described
in paragraph 78 and equation (14) of Chen.8 Despite these differences, the
Examiner does not explain why it would have been obvious for one of
ordinary skill in the art to apply Cheng’s disclosure (i.e., that an equation
describing a voltage limit ellipse can be a function of flux linkage) to Chen’s
equation for determining a torque capability threshold value (i.e., IqMax).
In the rejections of independent claims 7 and 13, the Examiner makes
similar findings and conclusions as in the rejection of claim 1 with regard to
the disclosure in Chen and Cheng of a single independent variable look-up
table for a torque capability threshold value. Final Act. 2—8. Therefore, the
rejections of claims 7 and 13 have the same deficiency as the rejection of
claim 1.
In view of the foregoing, we conclude that the Examiner has not set
forth a prima facie case of obviousness. In re Oetiker, 977 F.2d 1443, 1445
(Fed. Cir. 1992) (The Examiner “bears the initial burden ... of presenting a
prima facie case of unpatentability.”). Therefore, we cannot uphold the
Examiner’s § 103(a) rejection over Chen and Cheng.
7 Final Act. 3.
8 With regard to the Examiner’s finding that the flux linkage disclosed in
column 8, lines 46-49, of Cheng could be rewritten as “2/(pi*(wr/Vdc))”
(Final Act. 3), it appears the Examiner is using the equation for operating
flux linkage, k0. See Cheng 8:27—30. However, Cheng states that if all the
motor parameters of equation (7) are fixed, the voltage ellipse is a function
of flux linkage y, which is a ratio of Vo (maximum motor voltage) to co
(rotor speed). Id. at 4:3, 4:10, 7:55, 8:46-49. The Examiner does not
explain why one of ordinary skill in the art would have used the equation for
operating flux linkage k0 instead of the equation for flux linkage y.
5
Appeal 2017-002454
Application 13/607,008
The remaining § 103(a) rejection includes Aoki as an additional
reference and has the same deficiency as the § 103(a) rejection of claim 1.
Although the remaining § 103(a) rejection relies on Aoki as an additional
prior art reference, the Examiner does not rely on Aoki to remedy the
deficiency in the combination of Chen and Cheng. Therefore, we also
cannot uphold the Examiner’s § 103(a) rejection over Chen, Cheng, and
Aoki.
SUMMARY
The Examiner’s decision to reject claims 1, 2, 5—8, 11—13, 17, 20, and
21 is reversed.
REVERSED
6