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Development of a Power Electronics Controller for the Advanced Stirling Radioisotope GeneratorUnder a U.S. Department of Energy program for radioisotope power systems, Lockheed Martin is developing an Engineering Unit of the Advanced Stirling Radioisotope Generator (ASRG). This is an advanced version of the previously reported SRG110 generator. The ASRG uses Advanced Stirling Convertors (ASCs) developed by Sunpower Incorporated under a NASA Research Announcement contract. The ASRG makes use of a Stirling controller based on power electronics that eliminates the tuning capacitors. The power electronics controller synchronizes dual-opposed convertors and maintains a fixed frequency operating point. The controller is single-fault tolerant and uses high-frequency pulse width modulation to create the sinusoidal currents that are nearly in phase with the piston velocity, eliminating the need for large series tuning capacitors. Sunpower supports this effort through an extension of their controller development intended for other applications. Glenn Research Center (GRC) supports this effort through system dynamic modeling, analysis and test support. The ASRG design arrived at a new baseline based on a system-level trade study and extensive feedback from mission planners on the necessity of single-fault tolerance. This paper presents the baseline design with an emphasis on the power electronics controller detailed design concept that will meet space mission requirements including single fault tolerance.
Document ID
Document Type
Technical Memorandum (TM)
Leland, Douglas K.
(Lockheed Martin Corp. Denver, CO, United States)
Priest, Joel F.
(Lockheed Martin Corp. Denver, CO, United States)
Keiter, Douglas E.
(SunPower, Inc. Athens, OH, United States)
Schreiber, Jeffrey G.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 24, 2013
Publication Date
February 1, 2008
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
AIAA Paper 2007-4737
Meeting Information
Fifth International Energy Conversion Engineering Conference and Exhibit(St. Louis, MO)
Distribution Limits
Public Use Permitted.
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