On the Power System of the AMALIA Moon rover

This work deals with the Electrical Power System of the Lunar Rover, developed for the AMALIA mission, intended to compete in the Google Lunar X prize. The main subsystems are described and their operation analyzed on the basis of the observed experimental behavior. Primary generation is provided by triple-junction solar cells, arranged as four sections, each connected to a dedicated Array Power Regulator with separate Maximum Power Point Tracking. A Switch Matrix allows to rearrange the inter-connections among the Solar Array sections and the APR in order to manage possible failures. During load peaks and/or with low Sun elevation the solar array is supported by a secondary generator consisting of three redundant units with Li-Ion battery cells. Two alternate configurations of the Battery Subsystem were developed: a classical 8S Li-Ion battery, for a 28V Sun-regulated bus, and a novel approach, based on a single-cell (1S) Li-Ion battery and a high-voltage-gain Battery Charge-Discharge Regulator. A specific converter was designed for this configuration, based on the non-insulated Three Levels Neutral Point Clamped switching converter topology. Its correct operation with bus voltages up to 48V and fully discharged battery cells was demonstrated.