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Method of detecting system function by measuring frequency response

United States Patent

April 3, 2012
View the Complete Patent at the US Patent & Trademark Office
Idaho National Laboratory - Visit the Technology Transfer and Commercialization Office Website
Method and Apparatus for In-Situ Real Time Characterization of Energy Storage and Energy Conversion Devices
Real-time battery impedance spectrum is acquired using a one-time record. Fast Summation Transformation (FST) is a parallel method of acquiring a real-time battery impedance spectrum using a one-time record that enables battery diagnostics. An excitation current to a battery is a sum of equal amplitude sine waves of frequencies that are octave harmonics spread over a range of interest. A sample frequency is also octave and harmonically related to all frequencies in the sum. The time profile of this signal has a duration that is a few periods of the lowest frequency. The voltage response of the battery, average deleted, is the impedance of the battery in the time domain. Since the excitation frequencies are known and octave and harmonically related, a simple algorithm, FST, processes the time record by rectifying relative to the sine and cosine of each frequency. Another algorithm yields real and imaginary components for each frequency.
Morrison; John L. (Butte, MT), Morrison; William H. (Manchester, CT), Christophersen; Jon P. (Idaho Falls, ID)
Battelle Energy Alliance, LLC (Idaho Falls, ID), Montana Tech of the University of Montana (Butte, MT), Qualtech Systems, Inc. (East Hartford, CT)
12/ 217,013
June 30, 2008
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT The subject invention was made with government support under a research project supported by NASA, Grant No. NNA05AC24C. The government has certain rights in this invention. Further, the United States Government has certain rights in this invention pursuant to Contract No. DE-AC07-05ID14517 between the United States Department of Energy and Battelle Energy Alliance, LLC.