Ensuring Large-Displacement Stability in AC Microgrids
Abstract
Aerospace and shipboard power systems, as well as emerging terrestrial microgrids, typically include a large percentage of regulated power-electronic loads. It is well known that such systems are prone to so-called negative-impedance instabilities that may lead to deleterious oscillations and/or the complete collapse of bus voltage. Numerous small-displacement criteria have been developed to ensure dynamic stability for small load perturbations, and techniques for estimating the regions of asymptotic stability about specific equilibrium points have previously been established. However, these criteria and analysis techniques do not guarantee system stability following large and/or rapid changes in net load power. More recent research has focused on establishing criteria that ensure large-displacement stability for arbitrary time varying loads provided that the net load power is bounded. These Lyapunov-based techniques and recent advancements in reachability analysis described in this thesis are applied to example dc and ac microgrids to not only introduce a large-displacement stability margin, but to demonstrate that the selected systems can be designed to be large-displacement stable with practicable constraints and parameters.
Degree
Ph.D.
Advisors
Wasynczuk, Purdue University.
Subject Area
Design|Mathematics|Political science
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