Accurate Power Sharing and Voltage Restoration in DC Microgrids With Heterogeneous Communication Time Delays

Abstract

In order to realize power sharing and voltage restoration in islanded microgrids, consensus-based control schemes (CBCSs) have been extensively studied recently due to their flexibility and reliability. Nevertheless, due to heterogeneous communication time delays, it is impossible to achieve accurate power sharing and voltage restoration with the conventional CBCS. In this article, we propose an enhanced CBCS, in which average microgrid voltage and per unit power estimators have been developed based on standard proportional-integral (PI) consensus algorithms and scattering transformations. Thanks to the proposed estimator, the adverse impact of time delays on stability and accuracy is removed, and accurate power sharing and voltage restoration are always achieved regardless of heterogeneous time delays. The effectiveness and feasibility of the control scheme have been theoretically analyzed and validated via simulations and experiments.