Electric power processing, distribution and control for advanced aerospace vehicles

The results of a current NASA study program to develop a rational basis for selection of power processing, distribution and control configurations for future aerospace vehicles including the Space Station, Space Shuttle, and high performance aircraft are presented. Within the constraints imposed by the characteristics of power generation subsystems and the load utilization equipment requirements, the power processing, distribution and control subsystem can be optimized by selection of the proper distribution voltage, frequency, and overload/fault protection method. It will be shown that for large space vehicles which rely on static energy conversion to provide electric power, high voltage dc distribution (above 100 Vdc) is preferable to conventional 28 Vdc and 115 Vac distribution per MILSTD- 704A. High voltage dc also has advantages over conventional constant frequency ac systems in many aircraft applications due to the elimination of speed control, wave shaping, and synchronization equipment. These conclusions are based on detailed design analyses of power processing equipment, switchgear, and cables as a function of voltage, frequency, power level, and control method.