A Novel Control Scheme for High Efficiency Fuel Cell Power Systems in Parallel Structure

This work presents a simple control method for high efficiency power converters of a fuel cell (FC) distributed generation (DG) system. In general, to satisfy the required power rating of FC DG systems, multiple FCs and power conversion systems are used in parallel. In this paper, for high efficiency of the parallel system under light-load conditions, the number of operating units is adjusted so that the core and switching losses can be considerably reduced. A loss analysis is presented to maximize light-load efficiency, where the system operates most of the time. The control block diagram based on the lifespan of power conversion units is discussed in order to achieve balanced operating time. Finally, for a total 900 W FC DG system, three 300 W prototype units were built and verified for the proposed approach.