Study of DC microgrid transition control between grid-connected and islanded mode

Abstract

DC microgrids offer several advantages, including suitability for storage systems, resilience, flexibility, high efficiency, and the ability to operate independently from the main grid during outages, faults, or other disruptions. This research examines DC microgrids, with a focus on converters and control methods, to develop a model capable of operating in both gridconnected and islanded modes. The simulation model was developed using MATLAB/Simulink software, incorporating all essential components, including a PV system, unidirectional and bidirectional DC-DC converters, and a bidirectional AC-DC converter. The study focused on the transition between grid-connected and islanded modes, which is characterized by a voltage overshoot during the transition. This overshoot is more pronounced when transitioning from grid-connected to islanded mode and less significant in the reverse transition. Various control methods were tested to achieve smooth transitions between islanded and gridconnected modes. These methods include feedback control, sliding mode control, compensation, and voltage level control.