An efficient energy-management strategy for a DC microgrid powered by a photovoltaic/fuel cell/battery/supercapacitor.

The outcome of this paper is to suggest an efficient energy-management strategy (EMS) for a direct-current (DC) microgrid (MG). The typical MG is composed of two renewable energy sources [photovoltaic (PV) systems and fuel cells (FCs)] and two energy-storage elements (lithium-ion battery and supercapacitor). An EMS was proposed to ensure optimal bus voltage with a power-sharing arrangement between the load and the sources. As a result, in the suggested DC MG, non-linear flatness control theory was used instead of the traditional proportional-integral control approach. The suggested EMS is intended to supply high power quality to the load under varying load conditions with fluctuating solar irradiation while considering the FC status. To validate and prove the effectiveness of the proposed EMS, a MATLAB® environment was used. In addition, the output power of the PV system was maximized using the particle swarm optimization algorithm as a maximum power point tracking (MPPT) technique to track the MPP of the 3000-W PV system under different irradiance conditions. The results show that the suggested EMS delivers a stable and smooth DC bus voltage with minimum overshoot value (0.1%) and improved ripple content (0.1%). As a result, the performance of the DC MG was enhanced by employing the flatness control theory, which provides higher power quality by stabilizing the bus voltage. [ABSTRACT FROM AUTHOR]