Ensuring Large-Displacement Stability in Aircraft and Shipboard DC Power Systems

Due to the instabilities that may occur in dc power systems with regulated power-electronic loads such as those used in aircraft, ships, as well as terrestrial vehicles, many analysis techniques and design methodologies have been developed to ensure stable operation for expected operating conditions. However, these techniques do not guarantee large-displacement stability following major disturbances such as faults, regenerative operation, large pulsed loads, and/or the loss of generating capacity. Recently, a design paradigm was set forth that ensures large-displacement stability for any single positive or negative step change in commanded load power P-L provided the step change lies within the steady-state rating of the source. In this paper, a formal mathematical definition of large-displacement stability is set forth and the previous results are extended to show that it is possible to design a dc system that is large-displacement stable for any piecewise continuous P-L (t) that is bounded by the steady-state rating of the dc source. Moreover, and a new large-displacement stability margin is set forth and illustrated for two example systems.