Performance of grid-integrated photovoltaic/fuel cell/ electrolyzer/battery hybrid power system

Integration of different energy sources and power converters is required to meet the load demands adequately under various natural conditions. This research work focuses on the hybrid power system combining renewable energy sources, namely, a photovoltaic (PV) array and a solid oxide fuel cell (SOFC) and a hybrid energy storage system, i.e., a battery bank and hydrogen storage tanks in the proposed architecture. The complete layout is connected to the national grid via power electronics converters to enhance the continuity and reliability of power. In the proposed system, the PV is taken as the primary energy source to satisfy the load demands. The fuel cell and electrolyzer are added to ensure long-term energy balance by using the hydrogen technology. The battery is utilized as a high energy density device to keep the DC-bus voltage constant. The dynamic behaviour of the proposed system is checked under different solar radiation, temperature and load conditions for the simulation of 24 Hrs. The proposed system exhibits excellent performance in terms of grid stability and voltage regulation. All the energy sources and their controllers are designed in Matlab/Simulink.

I. Introduction

Depletion of fossil fuel, pollution problems, continuous increase in population growth and increase in demand about the accessibility of power and modern power electronics paved an opportunity for the maximum use of renewable energy sources (RES) such as solar, wind and fuel cell [1]. However, these RES experience some deficiencies and some fundamental problems when utilized as stand-alone energy sources. The output power generated by PV systems is highly dependent on weather conditions. Natural variations in solar irradiance and temperature causes power fluctuations in a PV system. Apart from this, the power generated by a PV system is difficult to store for backup [2].