A single-stage three-phase fuel cell system based on a boost inverter with a battery back-up unit

A conventional low-voltage unregulated fuel cell (FC) system requires a two-stage converter in order to generate AC power for typical loads or grid connection. In this paper, a three-phase boost inverter topology that achieves both boosting and inversion functions in a single-stage is used as a building block to develop a three-phase FC-based energy system which offers high conversion efficiency, low-cost and compactness. Additionally, the proposed FC system incorporates a back-up unit with battery storage to support the slow dynamics of the FC. The three-phase output voltage of the boost inverter is voltage-mode controlled and the back-up unit is current-mode controlled. Analysis, simulation and experimental results from a laboratory prototype are presented to confirm the operational performance of the proposed system.