Inertia Emulation with the Concept of Virtual Supercapacitor for Islanded DC Microgrid

In recent years, the use of renewable energy sources (RESs) has been increased due to the limited resources of fossil fuels and their environmental issues. The expansion of RESs and advances in power electronics have led to more attention being paid to DC microgrids (DCMGs). DCMGs enable the exploitation of all renewable energy potentials. Along with the advantages of RESs and DCMGs, the use of RESs is associated with the challenges of absence or lack of inherent inertia. Therefore, DCMGs have become more sensitive to disturbances. Rotational inertia is an inherent property of rotating machines that increases stability in the grid. Therefore, by applying energy storage systems (ESSs) in DCMGs, and inertia emulation the mentioned challenges can be overcome. The proposed control scheme is implemented based on the concept of the virtual supercapacitor in the inner control loop of the ESS interface dual-half-bridge (DHB) converter with DCMG to emulate the inertia. Due to the high efficiency, electrical insulation, inherent soft switching, and the need for a smaller filter, the DHB converter has been used. Finally, a DCMG is simulated for the effectiveness of the proposed control strategy in MATLAB/Simulink. The simulation results confirm the validity of the proposed scheme.