Stabilization of DC Microgrids with Point-of-Load Converters as Constant Power Loads

Abstract

DC-DC switching power converters exhibit the important characteristic of almost-perfect regulation at the output terminals independent of the input perturbations. However, such characteristic reflects at the input terminal as a constant power load (CPL). Microgrids (MGs) consists of multiple converters to satisfy the different voltage levels that loads need and stability problems are caused due to the interaction of Point-of-Load (POL) converters. In this context, this paper focuses on the stability analysis of POL converters as CPLs. In particular, POL converters are modeled using boost and buck converter topologies and the stabilization of POL converters is performed with different classic and modern control strategies, such as output feedback and state feedback. The performance analysis of the controllers is carried out using the Integral Squared Error (ISE), the Integral Time-weighted Squared Error (ITSE) and the Integral Squared of Control Signal (ISSC) performance indices.