Control and analysis of a hybrid renewable energy-based power system

This paper proposes a methodology for the integration of various energy sources into a hybrid generation system for stand-alone power applications. The system employs a wind generator (WG) and photovoltaic (PV) arrays as main energy sources while a fuel cell (FC) is included for supplying excess power demand. An ultra-capacitor (UC) bank is also implemented in order to cover rapid changes of both load demand and power supply due to changes in wind speed or solar radiation. The system operation is based not only on the supply-demand equilibrium but also includes concerns of FC long-term durability as well as actual constraints regarding electrolyzer operation and considerations of energy efficiency. The system performance is evaluated on a 24-hour operating time period basis under highly-varying load conditions. A particular control technique is proposed for power flow regulation ensuring both firm system performance and uninterrupted supply of load demand.