Abstract
A fundamental study on solar power generation system using Stirling engine for space application had been performed in the National Aerospace Laboratory of Japan (NAL). The Stirling engine is one of candidates for power converter for future space use. The prototype engines, called the NALSEM (NAL Stirling Engine Model) series, are semi-free-piston Stirling engines with a moving-magnet linear alternator. A basic model of the Stirling engine converter, called NALSEM500, has een experimentally studied since April 1994. The NALSEM 500 was designed to achieve a target thermodynamic efficiency of 30% or more with an indicated power of 500 W. After that, an improved Stirling engine converter, NALSEM700, has been designed and evaluated. This engine has opposed piston configuration in order to minimize mechanical vibrations. Based on these achievements, we designed a basic model of a free-piston Stirling engine converter. The converter is called the NALSEM200, and designed to achieve an overall efficiency of 20 % or more with an electrical output power of 200 W. In order to achieve the design performance, design optimizations are in progress at JAXA (Japan Aerospace Exploration Agency). This paper describes the significant design features and some results of preliminary bench tests on the NALSEM200.
