Analysis and simulation of electric power systems for aerospace Applications

Abstract

The Electrical Power Subsystem (EPS) plays a critical role in satellite design, providing the required electrical energy to operate all on-board systems. Their reliability and efficiency are essential for the success of a space mission, as any failure in this system can have catastrophic consequences. Consequently, a detailed and accurate design of the power subsystem is essential, taking into account several scenarios and contingencies that may arise during the mission. To achieve a reliable and efficient design, accurate models of the main components are required. These models facilitate both preliminary designs and complex simulations, allowing a comprehensive assessment of the performance of the power subsystem under different operational conditions. Within this context, this research proposes novel models and methods to improve the accuracy and reliability of the design of the power subsystem, with a specific focus on secondary energy sources.The first contribution presents a new methodology for conducting preliminary designs of electrical power subsystems in satellites, considering different architectures, variable efficiencies, and the utilization of batteries during both eclipse and daylight periods. The second contribution encompasses new models for Li-ion batteries. On the one hand, analytical solutions for a linear model of Li-ion batteries are developed. These solutions offer a straightforward and user-friendly approach to estimate battery performances under several conditions. This feature makes analytical solutions an indispensable tool for preliminary designs and for advanced simulations in which the batteries Depth of Discharge (DoD) is limited to increase their life-cycle. On the other hand, a new model for the open circuit voltage of Li-ion batteries is proposed. This contribution enables a more precise representation of the Li-ion batteries' static charging/discharging behavior for high DoD applications.