Recent research and development of alternative energy sources have shown excellent potential as a form of contribution to conventional power generation systems. In order to meet sustained load demands during varying natural conditions, different energy sources and converters need to be integrated with each other for extended usage of alternative energy. The paper focuses on the combination of wind, fuel cell (FC) and ultra-capacitor (UC) systems for sustained power generation. As the wind turbine output power varies with the wind speed: an FC system with a UC bank can be integrated with the wind turbine to ensure that the system performs under all conditions. We propose herein a dynamic model, design and simulation of a wind/FC/UC hybrid power generation system with power flow controllers. In the proposed system, when the wind speed is sufficient, the wind turbine can meet the load demand while feeding the electrolyzer. If the available power from the wind turbine cannot satisfy the load demand, the FC system can meet the excess power demand, while the UC can meet the load demand above the maximum power available from the FC system for short durations. Furthermore, this system can tolerate the rapid changes in wind speed and suppress the effects of these fluctuations on the equipment side voltage in a novel topology. (c) 2006 Elsevier B.V. All rights reserved.