Stability analysis of the International Space Station electrical power system

Two novel and efficient approaches to analyze the stability robustness at the interface between source and loads of a direct current (DC) distributed power system subject to loads that are turned on/off arbitrarily and operating at heavy/light power modes are presented. The first one is a rule based algorithm using the Nyquist stability criterion. The second one is based on the multivariable stability margin theory. Each of these two approaches provide a different perspective of the dynamic behavior of the system. The first one provides classical gain and phase margin, while the second one addresses the robustness of the system under simultaneous variations in the loadings. An analysis of the stability of the Flight 5A configuration of the International Space Station electrical power system (ISS EPS) using the Nyquist criterion is presented.