To meet the ever-increasing power demand of today's spacecraft systems, an integrated power electronics system capable of interfacing, and simultaneously controlling, three power ports will be designed and demonstrated in Phase I of the proposed project. This new proposed power electronic architecture employs a single-stage power topology, thus allowing cost-effective control of power flow with improved efficiency, power density, and reliability. This is achieved by modifying the switching patterns and control strategy of suitable conventional isolated converters, fully utilizing digital power electronics control methods. The result is multi-function utilization of converter components for increased capabilities with minimal effects on losses, size, weight and cost for such components. Moreover, existing engineering design concepts can be easily used to optimize the new proposed power topologies in a fashion similar to the conventional mother topologies including soft-switching techniques, component selection, and magnetic design procedures at higher switching frequencies. Each of these topologies is capable of performing simultaneous control of two of its three ports from battery or ultra-capacitor charge regulation, solar array peak power tracking, and/or load voltage regulation. Such converters are valuable alternative for designers of power systems requiring multiple power sources, or interfaced to power storage devices.