Hydrogen back-up power system with photovoltaic direct energy transfer regulation and interleaved boost for space applicattions

This work details a power conditioning unit for photovoltaic/hydrogen based energy systems in space applications. The power conversion techniques applied are similar to the ones used on photovoltaic/battery space power systems. A direct energy transfer photovoltaic regulator is devised for feeding two outputs; the first output corresponds to the main unregulated battery bus and the second output sets a power path to feed an electrolyser. A modular fuel cell converter completes the system and operates when photovoltaic energy is not available or load demand exceeds the generated photovoltaic power, providing electrical power from a fuel cell. An ancillary battery, located in the main bus, distributes an unregulated bus voltage in the main bus and also aids the fuel cell during transients or start-up processes. A 1kW prototype has been designed and implemented to assess the proposed system.