DC/DC Converter for the International Space Station

Abstract

A dc/dc converter for power distribution aboard the International Space Station (ISS) and space vehicles employing the 120 V dc bus is proposed. It is well suited to supply power to multiple loads including peripheral low voltage point-of-load (POL) regulators. The dc/dc converter is phase-shift controlled at the constant frequency of 500 kHz. The topology is characterized by distribution in a sequence of 4 metal-oxide semiconductor field-effect transistors (MOSFETs), switched ON at zero voltage. The linear model has first-order dynamics. Responses to small and large load variations benefit from its advantageous control features. A peculiar characteristic is its high dynamic independence of load typology and output power. To focus on this quality, dynamic performances are investigated through analyses, simulations, and measurements considering three types of loads: constant current, resistive, and constant power. Experimental data from a 100 W prototype fit the model forecasts well.