Distributed electrical power supply for a picosatellite

Abstract

During the launch of large satellites, the solar panels are folded away and after deployment the panels would be pointed at the sun. However, in this case, where picosatellite (PQ) is used, there is limited capacity for using foldable solar panels therefore six solar panels are used to cover the entire surface of cubic PQs. This means the panels of the satellite would receive different and changing amounts of light and thus each panel needs its own maximum power point tracker (MPPT). The power from all solar panels must efficiently combine at the point of common coupling (PCC), while regulating the voltage to charge the batteries and reach the energy consumers in the spacecraft. This project aims to develop a resilient and intelligent DC-Picogrid architecture internal to a picosatellite to combine power from each panel and ration it appropriately between each consumer and storage, without allowing any single point failure to propagate throughout the Picogrid. Since the design of the MPPT was conducted in previous studies, this project focuses on continuing the design of the electrical power supply (EPS) and commences from the design of the PCC to the design of the power distribution stage taking into consideration the limited capacity available on the finalized PCB. The first aim is to design a PCC which combines the designed six panels into this particular point. The next step will focus on designing the protection circuit required to be able to charge and discharge the battery in a safe manner to avoid failures. Examples include a protection circuit used to monitor the state of the battery to avoid overcharge and over-discharge the batteries. Finally, this project aims to design an efficient power distribution stage, which would consist of protected regulated and unregulated branches, to be able to provide the required energy to the consumers without allowing any single point of failures. The testing process was conducted by following several steps. The first step is to simulate and test each designed circuit and ensure its functionality. Next, each stage was tested as a standalone stage and the expected operation of each stage was obtained. Finally, the main EPS board was designed and manufactured.