Energy management strategy for a fuel cell/ultracapasitor/battery hybrid system for portable applications

A proton exchange membrane (PEM) fuel cells (FCs) with ultracapacitor (UC) and battery (BT) hybrid system has fast transient response compare to stand alone FCs. This hybrid system is promising candidates for environmentally friendly alternative energy sources. An energy management system design and control strategy was introduced in this study. The energy management strategy FC/UC/BT hybrid system model has been developed and the control strategy was programmed in the LabVIEWTM environment and implemented using National Instrument (NI) devices. The energy management strategy is able to manage the energy flow between the main power source (FCs) and auxiliary sources (UC and BT). To control the hybrid system and achieved proper performance, a controller circuit was developed with the three energy sources aligned in parallel to deliver the requested power. The developed model demonstrates the proportion power from the FC, UC and BT under various load demand. Experimental results demonstrate that FC/UC/BT hybrid system operated automatically with the varying load condition. The experimental results are presented; showing that the proposed strategy utilized the characteristic of both energy storage devices thus satisfies the load requirement.