Large-Signal Stability Criteria in DC Power Grids With Distributed-Controlled Converters and Constant Power Loads

The increasing adoption of power electronic devices may lead to large disturbance and destabilization of future power systems. However, stability criteria are still an unsolved puzzle, since traditional small-signal stability analysis is not applicable to power electronics-enabled power systems when a large disturbance occurs, such as a fault, a pulse power load, or load switching. To address this issue, this paper presents for the first time the rigorous derivation of the sufficient criteria for large-signal stability in DC microgrids with distributed-controlled DC-DC power converters. A novel type of closed-loop converter controllers is designed and considered. Moreover, this paper is the first to prove that the well-known and frequently cited BraytonMoser's mixed potential theory (published in 1964) is incomplete. Case studies are carried out to illustrate the defects of BraytonMoser's mixed potential theory and verify the effectiveness of the proposed novel stability criteria.