US H2,146 H1Granted

Method for determining long term stability

AssigneeUnited States of America

InventorsRobert N. Burnfield, Larry E. Meister, David R. Stubbs

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Abstract

A method of determining long term power variation, as an indication of long term stability of power output, by steps of measuring power output at successive intervals of time, determining variations in power output, from an average power output, at corresponding intervals of time, making a Fourier transform of each variation in power output, calculating a power spectral density from each Fourier transform, plotting a log of each power spectral density, extrapolating the plot to find a value, designated as a log of a power spectral density, from the plot, calculating a power spectral density from the found value of the log of the power spectral density, and making an inverse Fourier transform of the calculated power spectral density, to determine the long term power variation.

Claims1

Dependent claims

A method of determining power variation Delta PTA as an indication of long term stability of power output, comprising:

(a) determing power output at successive intervals of time T beginning at a first interval of time T2 and continuing to an interval of time T1, where time T1 is shorter than an interval of time TA;
(b) determining variations, Delta PT2 to Delta PT1, in power output, from an average power output P, at corresponding intervals of time T2 to T1;
(c) making a Fourier transform of each variation in power output;
(d) calculating a power spectral density, from (PSD)T2 to (PSD)T1, from each Fourier transform, at a frequency fT, where T is the interval of time associated with each Fourier transform;
(e) plotting of a log of each power spectral density (PSD)T2 to (PSD)T1 at a log of the associated frequency f, on a log-log plot form;
(f) extrapolating a value designated as a log of a power spectral density (PSD)TA, at a log of frequency fA, where fA equals 1/TA, from the plot form;
(g) calculating the power spectral density (PSD)TA from the log of the power spectral density (PSD)TA;
(h) making an inverse Fourier transform of the power spectral density (PSD)TA to determine power variation Delta PTA.

5 more elements

Dependencies are inferred from the claim text.