Stability Analysis of Spacecraft Power Systems

This paper discusses the problems that exist in applying standard electric utility models, analyses, and algorithms to the study of the stability of spacecraft power conditioning and distribution systems. Both single-phase and three-phase systems are considered. Of particular concern are the load and generator models that are used in terrestrial power system studies as well as the standard assumptions of load and topological balance that lead to the use of the positive sequence network. The paper also examines the standard assumptions regarding relative speeds of subsystem dynamic responses that are made in the classical "transient stability algorithm" that forms the backbone of utility-based studies. The applicability of these assumptions to a spacecraft power system stability study are discussed in detail. In addition to the classical "indirect" method, this paper also discusses the applicability of Liapunov's direct methods to the stability determination of spacecraft power systems. Some preliminary results are given for a linear-graph, state-variable based modeling approach to the study of the stability of space based power distribution networks.