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Improved L-C resonant decay technique for Q measurement of quasilinear power inductors: New results for MPP and ferrite powdered coresThe L-C resonant decay technique for measuring circuit Q or losses is improved by eliminating the switch from the inductor-capacitor loop. A MOSFET switch is used instead to momentarily connect the resonant circuit to an existing voltage source, which itself is gated off during the decay transient. Very reproducible, low duty cycle data could be taken this way over a dynamic voltage range of at least 10:1. Circuit Q is computed from a polynomial fit to the sequence of the decaying voltage maxima. This method was applied to measure the losses at 60 kHz in inductors having loose powder cores of moly permalloy and an Mn-Zn power ferrite. After the copper and capacitor losses are separated out, the resulting specific core loss is shown to be roughly as expected for the MPP powder, but anomalously high for the ferrite powder. Possible causes are mentioned.
Document ID
19950027453
Document Type
Contractor Report (CR)
Authors
Niedra, Janis M. (NYMA, Inc. Brook Park, OH, United States)
Gerber, Scott S. (NYMA, Inc. Brook Park, OH, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1995
Subject Category
ELECTRONICS AND ELECTRICAL ENGINEERING
Report/Patent Number
E-9823
NASA-CR-198373
NAS 1.26:198373
Funding Number(s)
CONTRACT_GRANT: NAS3-27186
PROJECT: RTOP 233-01-0C
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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