Design and testing of a breadboard electrical power control unit for the Fluid Combustion Facility experiment

The Fluid Combustion Facility (FCF) Project at the NASA Lewis Research Center in Cleveland, OH and the Sundstrand Corporation in Rockford, IL are jointly developing an electrical power converter unit (EPCU) for the Fluid Combustion Facility to be flown on the International Space Station (ISS). The FCF experiment contains three racks: a core rack; a combustion rack; and a fluids rack. The EPCU will be used as the power interface to the ISS 120V_DC power distribution system by each FCF experiment rack which requires 28V_DC. The EPCU is a modular design which contains three 120V _DC-to-28V_DC full-bridge, power converters rated at 1 kW_e each; bus transferring input relays and solid-state, current-limiting input switches; 48 current-limiting, solid-state, output switches; and control and telemetry hardware. The EPCU has all controls required to autonomously share power among the power converters and-if absolutely necessary-shed loads. The EPCU, which maximizes the usage of allocated ISS power and minimizes loss of power to loads, can be paralleled with other EPCUs. This paper overviews the electrical design and operating characteristics of the EPCU and provides test data for a breadboard design