Fuzzy based frequency control in an isolated network employing parallel operated fuel cell/ultra-capacitor systems

This paper proposes a fuzzy logic controller for power management of hybrid wind turbine (WT), photovoltaic (PV), fuel cell (FC), and ultra-capacitor (UC) for stand-alone applications. WT and PV are the primary power sources of the system, and an FC is expected to provide long-term energy balance, whereas the UC is employed as buffer storage for the short-term compensation. The improvement in fuzzy logic strategies enhances dynamic response of the FC/UC power system under various load conditions by suitable rule base design for fuzzy controller. The combined use of FC and UC has the potential for better energy efficiency and lifetime increment of FC technology. These rules are designed such that charging and discharging the UC voltage is controlled automatically. The fuzzy controller creates a balance between production and consumption with determination of the exact reference values for WT, PV, and FC. This causes a good frequency controlled in the hybrid generation power system. The fuzzy logic strategies performance under different condition has been verified by using real weather data practical load demand profile. To demonstrate the effectiveness of the proposed fuzzy logic strategies, comparison with improved frequency control method was performed using matlab/simulink by integrating the detailed mathematical and electrical models of the hybrid generation power system.