UNISAT-3 Power system

none4A general overview of the UNISAT-3 microsatellite power subsystem is given. This is an educational, low weight and low cost microsatellite designed built and operated in space by students of Scuola di Ingegneria Aerospaziale at University of Rome “La Sapienza”. The satellite main power system is based on terrestrial technology solar arrays and NiCd batteries. Together with the main photovoltaic system the microsatellite hosts different solar arrays (multi-junction cells, mono-crystalline silicon high efficiency cells) in order to compare their behaviour in orbit. Moreover a MPPT (Maximum Power Point Tracking ) system has been designed and tested, and it is a technological payload of UNISAT-3. The MPPT design follows the studies performed in the field of solar powered racing cars, with modifications to make the system suitable for use in space. The system design, numerical simulation and hardware ground testing are described in the paper. The experiment and the performance evaluation criterion are described, together with the preliminary results of the first eight months of operationnoneF. Santoni; F. Piergentili; F. Bulgarelli; F. GrazianiF. Santoni; F. Piergentili; F. Bulgarelli; F. Grazian