A new control strategy for hybrid fuel cell-battery power systems with improved efficiency

In this paper, a new hybrid fuel cell-battery power system with a single DC-DC boost converter is proposed to supply a simple, low cost, and highly stable load-sharing characteristic, which the fuel cell is acted as a main power source and the battery as an energy balancer except for supplying the fuel cell stack's auxiliary power and modulating the excessive or insufficient power for the load. The proposed control strategy for hybrid power sources system shows that with a decrease in battery size the hybrid fuel cell-battery will reduce the duration of power-sharing from batteries-dominated to fuel cells-dominated. As a result, not only the efficiency of fuel cell (FC) can be dramatically increased in partial load conditions, but also full recharging of battery in the proposed hybrid power system is more efficient when the load is less on-demand with a better overall efficiency. Finally, some experimental results are presented for verifying the effectiveness of the proposed hybrid FC-battery power system. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.