Power Management, Control and Optimization of Photovoltaic/Battery/Fuel Cell/Stored Hydrogen-Based Microgrid for Critical Hospital Loads

Abstract

Renewable-energy-based DC microgrids are acting as a possible replacement for the diesel-generator-based stand-alone power systems for critical loads as they are environment friendly, efficient and reliable. Research attention is required on optimization and effective power management of DC microgrids to address power failures and affordability issues. This paper performs optimization and proposes a power management strategy for a DC microgrid consisting of Solar PV/battery/fuel cell and stored hydrogen. A suitable case study is implemented in HOMER (Hybrid Optimization of Multiple Energy Resources) to check the feasibility of the proposed system configuration for the remote location of North India (74.75∘ E and 34.05∘ N). The HOMER is used to evaluate the best system configuration in size and cost per unit of energy. A custom-based power management algorithm is suggested to enhance the proposed microgrid topology scope for any given site. The custom-based power management algorithm helps in effectively sharing the critical load demand among the various renewable power sources, considering the various parameters like battery state-of-charge (SOC) and availability of solar photovoltaic power. Time-domain simulations are performed to check the proposed custom-based power management algorithm’s microgrid response and effectiveness considering random solar irradiance profile and various operating modes. It is assumed that hydrogen is available in the tank and supplied to the fuel cell at a constant flow rate for the time-domain simulations. The contribution of this work is to describe the application of renewable-energy-based DC microgrid in electrifying ventilator critical loads, where load shedding is not feasible and neither allowed. The optimization results indicate the economic feasibility with the best optimal system configuration providing electricity at $ 0.186 with a total NPC of $83103. Time-domain simulations are performed in MATLAB/Simscape software and the results indicate the technical feasibility of electrifying the ventilator loads through the proposed renewable-energy-based DC microgrids.