Droop-Based DC Microgrids Analysis and Control Design Using a Weighted Dynamic Aggregation Modeling Approach

Abstract

In this article, a weighted dynamic aggregation (WD agg) approach is used for modeling, analyzing, and control loop design of islanded dc microgrids. The proposed approach models bf n dc-dc converters and their controllers with a single equivalent converter and an equivalent control system, which without sacrificing the accuracy reduces the complexity of such large-scale system studies. It is shown that the model equivalent converter and control system parameters can be determined by the weighted average of the corresponding parameters of the large-scale system. The weight of each converter is quantified based on the contribution of that converter in the overall dynamic behavior of the large-scale system. The WD agg model can accurately predicts the transient response and can be employed in power planning, stability, and sensitivity analyses with high accuracy. It is also shown that the proposed model can be used in designing the controller parameters of the large-scale system to ensure a desirable system performance. The accuracy and applications of the proposed WD agg model are evaluated through time-domain simulations, and experiments of an islanded microgrid consisting of three paralleled converters with different control parameters connected to a constant power load emulating a challenging system stability case.