Nidec Motor v. Zhongshan Broad Ocean Motor (Fed. Cir. 2017)
In a short and tidy opinion, the Federal Circuit has reversed a PTAB anticipation decision in an inter partes review – holding that the Board’s decision “is not supported by substantial evidence.”
At issue is claim 21 of Nidec’s U.S. Patent No. 7,208,895, which claims a “permanent magnet rotating machine and controller assembly configured to perform the method of claim 12.” Claim 12, in turn is a motor control-method that involves calculating two different phase currents:
The method disclosed in the ‘895 Patent relates to vector control of a permanent magnet machine in the rotating frame of reference. The claimed novel feature requires “combining” calculated Q-axis and d-axis currents to produce an “IQdr current demand” in the rotating frame of reference, which can later be further manipulated and back-transformed into the three phase currents in the stationary frame of reference that drive the motor. Combining the Q-axis and d-axis currents to produce a unitary IQdr demand occurs prior to the back-transformation process.
My reading of the single prior art reference (Kusaka, U.S. Patent No. 5,569,995) is that it also uses the same inputs to achieve a three-part motor-control output, but does not particularly disclose that the transformation happens by first combining the inputs and then transforming the combination into the three-part output. In its opinion, the Federal Circuit found this analysis compelling:
Because Kusaka does not disclose a signal in the rotating frame of reference, it does not disclose an IQdr demand.
Abstract Idea Creep: The decision approach here is important because it holds the line against encroachment of eligibility issues (Section 101) into the anticipation analysis. Notably, the identified inventive step here is essentially requiring a two-step mathematical transformation (with IQdr intemediary) rather than a single-step transformation done in the prior art. Of course, the claims themselves do not indicate how the combination occurs occurs – just requiring “combining” the inputs. I expect that a number of courts thinking about the eligibility analysis would see that step as lacking sufficient concrete inventiveness.
Remand? The court reversed, but did not indicate any remand. That suggests to me that the case is over with the patentee winning the IPR.
Claim Scope: I’m still somewhat confused about whether the claim structure used here is proper under the law. 35 USC 112 states that “A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.” In my mind, one element of claim 12 is that it is a “method” and claim 21 is a “machine . . . configured to perform the method.” As such, claim 21 cannot itself meet the method limitation of claim 12.
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12. A method of controlling a permanent magnet rotating machine, the machine including a stator and a rotor situated to rotate relative to the stator, the stator having a plurality of energizable phase windings situated therein, the method comprising: