Mode Transition in DC Microgrids with Non - Dispatchable Sources

DC microgrids have been gaining popularity over the past few decades. Most proposed works do not factor in the variabilities associated with the renewable power generation. The present work is aimed at validating a bus voltage signal method based strategy for a photovoltaic (PV) based DC microgrid system that is able to sustain load under both grid connected and islanded modes and ensures smooth mode transition factoring in the renewable intermittency. A power-based droop control technique is employed to determine the operating mode of the distributed energy resource (DER) converter. A battery energy storage system (BESS) interfaced through a bi-directional converter ensures that the PV panel operates at its maximum power point (MPP) at all loading conditions in both the modes. A total of eight possible scenarios in terms of load conditions, solar insolation variation and output power set-points are modelled and simulated in MATLAB Simulink environment and verified in real-time through controller-hardware-in-loop (CHIL) on an Opal-RT platform results are presented and discussed.