Analytical Approach to Define the Stability Boundaries in Controlled DC Microgrids

The DC technology is envisioned as the most promising alternative for the design of the new generation of shipboard power systems. The superior flexibility that the DC grids guarantee in respect to their AC counterpart make them the ideal candidate for the integration of demanding and high power loads. One of the components that make it possible to enhance the dynamics performance of such grids are definitely the power electronics converters. These fully controllable interfaces make it possible to easily coordinate the combination of generating sources, storages and loads, while guaranteeing adequate power quality. The price to pay for guaranteeing performing controls is the possibility to jeopardize the power system. Indeed, one of the risks of not properly controlled DC grids is the insurgence of voltage instability, an event that can possibly lead to a ship blackout. Considering systems with many converters the study of the voltage stability is not an easy task and certainly not doable with a full analytical approach. This is why this paper proposes a reduced-order approach for the problem to obtain a simplified analytical, yet approximated, expression of the system stability conditions.