New Sizing Methodology and Efficiency Analysis of Satellite’s Electrical Power Subsystem

This paper describes a novel methodology to improve the preliminary design and efficiency analysis of the satellite’s electrical power subsystem. Several studies have addressed this issue by proposing a solar array sizing method based on the use of fixed efficiency paths during sunlight and eclipse periods. Indeed, these studies restrict the use of the battery for eclipse periods, and thus the solar array is sized to support the peak power loads on its own. To the authors’ knowledge, no one has so far deeply and jointly analyzed the influence of the power profile demand, the use of the battery during sunlight periods, and the architecture on the efficiency paths to size the electrical power subsystem. This work offers a methodology that takes into account these variables to better estimate the global efficiency of the electrical power subsystem and, consequently, to refine the first design iterations of a satellite. This methodology is particularized for the most common architectures based on power and voltage bus regulation, although it can be implemented in more complex architectures. A case study involving a real space mission, the UPMSat-2 (a 50 kg satellite launched in September 2020), is conducted to test this methodology.