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Efficient Design in a DC to DC Converter UnitSpace Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.
Document ID
20020083039
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Bruemmer, Joel E.
(Boeing Co. Canoga Park, CA United States)
Williams, Fitch R.
(Boeing Co. Canoga Park, CA United States)
Schmitz, Gregory V.
(NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
September 7, 2013
Publication Date
August 1, 2002
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
NASA/TM-2002-211804
IECEC-2002-20032
NAS 1.15:211804
E-13499
Meeting Information
Meeting: 37th Intersociety Energy Conversion Engineering Conference
Location: Washington, DC
Country: United States
Start Date: July 28, 2002
End Date: August 2, 2002
Sponsors: Institute of Electrical and Electronics Engineers
Funding Number(s)
PROJECT: RTOP 478-29-10
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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