Appeal No. 1997-0211
Application No. 08/252,288
converter as disclosed by appellant as evidenced by the similar figures and same
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motivation to reduce harmonics discussed in the specification of Maddali. Further, the
Examiner asserts that it would have been obvious to one of ordinary skill in the art to use a
feedforward or predictive system as taught by Kislovski for better control of the system
than a feedback system would provide as taught by Maddali. We agree with the Examiner
with respect to the basic use of a predictive system. Maddali also discloses that the
switching angle is related to the output (See Maddali at col. 5, lines 21-27) and that the
“switching angles [are] determined by the result of comparing the composite waveform YCA
to the triangular waveform. As the harmonic content in the output of the inverter changes,
the composite waveform Y changes and the switching angles of the PWM pulses
CA
consequently change.” (See Maddali at col. 7, lines 57-62.) Clearly, Maddali teaches
there is a relationship of the switching angles to the output of the power converter.
Kislovski teaches a system for preventing transients from damaging a switching
regulator by use of predictive control. The system predicts the relevant values for use in
controlling the system. The “emergency control circuit” predicts in each time period
the size of the maximum current and intervenes to control when needed. (See Col. 4.)
2We note that the values used at the output are different for the instant disclosed invention in Fig. 1
as compared to Fig. 1 of Maddali, but this feature is not found in claim 1.
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