In this paper, an energy system comprising three energy sources, namely PV, wind and fuel cells, is proposed. Each of the three energy sources is controlled so as to deliver energy at optimum efficiency. Fuzzy logic control is employed to achieve maximum power tracking for both PV and wind energies and to deliver this maximum power to a fixed dc voltage bus. The fixed voltage bus supplies the load, while the excess power feeds the water electrolyzer used to generate hydrogen for supplying the fuel cells. A management system is designed to manage the power flow between the system components in order to satisfy the load requirements throughout the whole day. A case study is done using practical data from the El-Hammain site (40 km west of Alexandria, Egypt). The study defines the power generated by the wind and PV systems, the generated hydrogen used and stored in tanks and the power generated by the fuel cells to supply the deficiency in the load demand. Simulation results, done for two seasons, proved the accuracy of the fuzzy logic controllers. Also, a complete description of the management system is presented. (c) 2005 Elsevier Ltd. All rights reserved.
