Application of active current sharing control in fuel cell-battery off-line UPS system

Fuel cells are becoming more prevalent as the replacement for diesel/gasoline powered systems, such as vehicle and emergency power sources. However, cost and slow dynamic response of fuel cell still persist as the main disadvantage. To remedy this problem, an energy storage system with adequate power delivery has to be incorporated. This paper presents a low cost fuel cell-battery uninterruptible power supply (UPS) system. The control algorithm has been implemented using a digital signal processor. Active current sharing algorithm is implemented to adjust the output power from each source based on the load demand and battery state of charge. Experimental results are provided to demonstrate the static and dynamic performance of the system.