Power management in wind-fuel cell-ultracapacitor based autonomous hybrid power system

This paper presents modeling and simulation of a hybrid isolated power system consisting of wind, fuel cell, and ultracapacitor. A system under study is formulated by integrating different resources like proton exchange membrane fuel cell (PEMFC), wind and ultracapacitor (UC) as an energy storage option. The fluctuation in output power of wind energy system due its intermittency characteristic is minimized by integrating a combination of fuel cell and UC. The surplus of wind power is being converted and stored as hydrogen by the help of an electrolyzer and UC. Proportional-integral-derivative (PID) and two-degree-of-freedom PID (2-DOFPID) controllers are being incorporated into the hybrid system for improving the voltage profile. The hybrid system responses are studied for step variation in load and wind speed. Simulation results reflect that voltage variation using the proposed 2-DOFPID controller is less as compared to that of the conventional PID. The hybrid power system is modeled and simulated in MATLAB/SIMULINK environments.