NTRS - NASA Technical Reports Server

Back to Results
Control of Dual-Opposed Stirling Convertors with Active Power Factor Correction ControllersWhen using recently-developed active power factor correction (APFC) controllers in power systems comprised of dual-opposed free-piston Stirling convertors, a variety of configurations of the convertors and controller(s) can be considered, with configuration ultimately selected based on benefits of efficiency, reliability, and robust operation. The configuration must not only achieve stable control of the two convertors, but also synchronize and regulate motion of the pistons to minimize net dynamic forces. The NASA Glenn Research Center (GRC) System Dynamic Model (SDM) was used to study ten configurations of dual-opposed convertor systems. These configurations considered one controller with the alternators connected in series or in parallel, and two controllers with the alternators not connected (isolated). For the configurations where the alternators were not connected, several different approaches were evaluated to synchronize the two convertors. In addition, two thermodynamic configurations were considered: two convertors with isolated working spaces and convertors with a shared expansion space. Of the ten configurations studied, stable operating modes were found for four. Three of those four had a common expansion space. One stable configuration was found for the dual-opposed convertors with separate working spaces. That configuration required isochronous control of both convertors, and two APFC controllers were used to accomplish this. A frequency/phase control loop was necessary to allow each APFC controller to synchronize its associated convertor with a common frequency.
Document ID
Document Type
Conference Paper
Regan, Timothy F.
(Sest, Inc. Middleburgh Heights, OH, United States)
Lewandowski, Edward J.
(Sest, Inc. Middleburgh Heights, OH, United States)
Schreiber, Jeffrey G.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 25, 2013
Publication Date
June 26, 2006
Subject Category
Energy Production And Conversion
Report/Patent Number
Meeting Information
4th International Energy Conversion Engineering Conference(San Diego, CA)
Funding Number(s)
WBS: WBS 138494.04.01.01
Distribution Limits
Public Use Permitted.
No Preview Available