Accurate Power Sharing And Synthetic Inertia Control For Dc Building Microgrids With Guaranteed Performance

Accurate Power Sharing and Synthetic Inertia Control for DC Building Microgrids With Guaranteed Performance

Abstract:

Direct current (DC) building microgrids allow the integrations of DC distributed energy resources (DERs) and loads with a simpler topology and the elimination of alternating current (AC) system issues, such as frequency transients and harmonics. Because of the domination of power-electronics- interfaced generators, islanded DC microgrids in general present very low inertia, which reveals subtle stability threats to the systems. In addition, the conventional droop-based DER power-sharing mechanisms may suffer from poor power-sharing accuracy and DC bus voltage deviations that require secondary restorations. In this paper, a novel control scheme for building-scale islanded DC microgrids is proposed based on finite control set model predictive control (FCS-MPC). A new DER power-sharing mechanism is devised by introducing a current-sharing vector in the controller formulation, which eliminates bus voltage deviation during load/DER fluctuation and offers plug-and-play capabilities. Moreover, for the first time, virtual capacitance control for DC microgrids is implemented in an FCS-MPC manner to enhance the adaptive synthetic inertia of DC bus.