A novel low cost power converter topology for active power injection in low voltage monophasic power line from fuel cells

This paper presents a novel power converter topology for PEM solid state fuel cells. The proposed topology consists in an integrated DC/DC and DC/AC converters that can inject electrical power from a low voltage fuel cell into a low voltage monophasic line (100-220Vac). As this topology is suitable to step-up low voltages presents in fuel cell stacks output, it can be also applied in photovoltaic solar panels. The proposed topology is derived from the common topology composed by two intermediary converters: a DC/DC step-up converter and a DC/AC converter, or a monophasic inverter bridge. However, both stages of the converter must operate symbiotically so there is no need of DC bus capacitor, which would be a relatively high voltage capacitor, nor even an inductor for the fuel cell output, which is a relatively high current inductor. Thus, high voltage capacitors and high current inductors are avoided. Compared to others existing fuel cell power converter systems, the proposed circuit has a lower cost, since it has less component count, smaller size, due to the reducing of passive energy storage components and, although it uses the same amount of power transistors, eight in total, only four of them needs to be high frequency transistors, so the other four works in the frequency of the grid. Eventually, simulation and experimental results are presented.