Early Oscillation Detection Techniques for Hybrid DCDC Converters
Early Oscillation Detection Techniques for Hybrid DC/DC Converters Description: FY 08 Plans: According to preliminary results from the FY 07 study, impedance and gain/ phase margin measurement methods are the effective and accurate methods available to evaluate hybrid DC/DC converter stability. To meet NASA urgent needs for mission assurance, the two stability evaluation methods are very necessary to be adopted to flight unit critical test procedures. However, the gain/phase method has limitations to converters without remote sense pins, so an oscillation detection technique based on small noise signal sensing and spectral analysis could be used to determine stability status for all types of NASA converters. This is particular valuable to ensure safety of flight parts during flight level tests and even flight missions. The goal of this study is to eliminate DC/DC converter instability problems by applying the two measurement methods to flight converter tests, and by developing a new method to monitor and detect early oscillations during part screening and flight level tests. Schedule/Costs: Total Full-Cost = ---- • Apply the impedance measurement method for NASA used flight DC/DC converters and input filters by standardizing the method and identifying possible test variations. • Apply the gain/phase margin measurement method for the flight converters by standardizing the method and identifying possible test variations. • Further develop the oscillation detection techniques, using electromagnetic sensor, band-pass filter and signal analysis. Deliverables: 1. Technical report on DC/DC converter stability measurement applications and results of the early oscillation detection technique. 2. Hybrid DC/DC Converter Stability Test System setup. NASA and Non-NASA Organizations/ Procurements: Lead Center/PI: GSFC, Bright Wang • 110 K for test activities. • 40 K for test equipment (Venable impedance test set, NI PXI modular instruments , Amplifiers, Active filters). • 98 K for components for testing (flight-grade dc/dc converters, EE parts to build test equipment). • 2 K for travels to vendor sits and conference.
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