Weighted Dynamic Aggregation Modeling of DC Microgrid Converters with Droop Control

Abstract

Weighted Dynamic Aggregated (WD) model is developed for parallel-connected DC-DC converters in islanded DC microgrids. The proposed model is obtained based on the contribution of each converter in the detailed model. The proposed reduced-order model can be used for stability analysis, sensitivity analysis, and designing the controller parameters of parallel converters with Constant Power Loads (CPLs). Unlike existing methods such as Tahim model and the multi-time scale model, the suggested WD method provides a single converter as an equivalent model for large-scale parallel converters while taking into account the converters control parameters and output LC filter. The proposed model is evaluated through time-domain simulation, stability analysis, and sensitivity analysis of 4-paralleled Buck converters connected to a CPL in four scenarios that cover a combination of different control parameters and output filter capacitance. The simulation results verify the accuracy of the suggested approach in both steady-state and transient behaviors.