Design of the Dynamic Power Compensation for PEMFC Distributed Power System

Transient load power may bring damage to the proton exchange membrane fuel cell (PEMFC) and shorten the lifetime of the stack. This paper introduces a dynamic power compensation unit consisting of a bidirectional dc/dc converter and a supercapacitor pack, used for compensating the slow dynamic response of the PEMFC and guaranteeing the operation safety of the fuel cell (FC) during load transitions. In this paper, the characteristics of PEMFC are first studied by an experiment, and then, the target of the dynamic power compensation is set based on the experimental results. Subsequently, an analysis on the dynamic power compensation and derivation of the design target is presented. The controller and the filter design based on these analyses are given. With regard to the hardware realization, the bidirectional dc/dc converter is then introduced. Finally, the experimental results on a 5-kW FC power system with dynamic power compensation are given to verify the theoretical analysis and the design. With the dynamic power compensation unit, the FC only needs to supply a slowly changing output power during the sharp load transition process. A more reliable operation condition can be achieved for the FC.