Development of a Multi -bus, Multi -source Reconfigurable Stirling Radioisotope Power System Test Bed
The National Aeronautics and Space Administration (NASA) has typic ally used Radioisotope Ther mo electric Gene rators (RTG) as their source of electric power for deep space missions. A more efficient and potentially more cost effective alternative to the RTG , the high efficiency 110 watt Stirling Radioisotope Generator 110 (SRG110) is being develope d by the Department of Energy (DOE), Lockheed Martin (LM), Stirling Technology Company (STC) and NASA Glenn Research Center (GRC). The SRG110 consists of two Stirling convertors (Stirling Engine and Linear Alternator) in a dual -opposed configuration , and two General Purpose Heat Source (GPHS) modu les. Although Stirling convertors have been successfully operated as a power source for the utility grid and as a stand -alone portable generator, demonstration of the technology required to interconnect two Stirl ing convertors for a spacecraft power system has not been attempted. NASA GRC is developing a Power System Test Bed (PSTB) to evaluate the pe rformance of a Stirling convertor in an integrated electrical power system application. This paper will describe t he status of the PSTB and on -going activities pertaining to the PSTB in the NASA Thermal -Energy Conversion Branch of the Power and On -Board Propulsion Technology Division.
A novel multi-port bidirectional converter for interfacing distributed DC micro-grid
A novel multi-port bidirectional DC-DC converter (MPBDC) is proposed for a stand-alone renewable power system which is composed of multiple distributed DC sub-systems. With the proposed MPBDC, the DC buses of these sub-systems can be interconnected with single stage and step-up/-down power conversion. The MPBDC is derived by interconnect multiple bidirectional buck/boost switching cells via DC-link inductors. The equivalent circuit between any two of the DC buses is a H-Bridge step-up/-down converter, which achieves single stage conversion. Compared with the conventional common DC-bus-based solution, the bulky DC-link capacitors have been eliminated with the MPBDC, which benefits reduced size, lower cost and better reliability. The operational principles, power management and pulse width modulation scheme are presented in detail. A prototype is built with experimental results given to verify the topology and control.
Impact testing of a Stirling convertor’s linear alternator
The U.S. Department of Energy (DOE), in conjunction with NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic impact tests were conducted at NASA Glenn Research Center’s Structural Dynamics Laboratory as part of the development of this technology. The purpose of this test was to identify dynamic structural characteristics of the Stirling Technology Demonstration Convertor (TDC). This paper addresses the test setup, procedure and results of the impact testing conducted on the Stirling TDC in May 2001.