A Single-Phase Grid-Connected Fuel Cell System Based on a Boost-Inverter

In this paper, the boost-inverter topology is used as a building block for a single-phase grid-connected fuel cell (FC) system offering low cost and compactness. In addition, the proposed system incorporates battery-based energy storage and a dc-dc bidirectional converter to support the slow dynamics of the FC. The single-phase boost inverter is voltage-mode controlled and the dc-dc bidirectional converter is current-mode controlled. The low-frequency current ripple is supplied by the battery which minimizes the effects of such ripple being drawn directly from the FC itself. Moreover, this system can operate either in a grid-connected or stand-alone mode. In the grid-connected mode, the boost inverter is able to control the active (P) and reactive (Q) powers using an algorithm based on a second-order generalized integrator which provides a fast signal conditioning for single-phase systems. Design guidelines, simulation, and experimental results taken from a laboratory prototype are presented to confirm the performance of the proposed system.