Multiple objective optimization in a spacecraft power system to maximize serviceability

Different from most power systems, the requirement for reliability of the power system on board a spacecraft is much more stringent. However, the reliability of the spacecraft power system can not be solely realized by increasing system redundancies due to limitations on mass. A Ring-Bus topology has been proposed for this purpose. This paper provides an analysis to this special topology, study selected critical possible failure scenarios and propose methods to maximize the serviceability of the system. A spacecraft power system is distinguished from most other system as it orbits around the earth. The primary source of the system is solar energy. Batteries save energy for ellipse time. To maximize the serviceability, the solar energy should be utilized most efficiently and the batteries should be strategically discharged to meet not only immediate load but anticipated load in the future. At the same time, the system should minimize current flows among different ring buses. Multiple objective functions are proposed and implemented in this paper based on different system operating conditions. The main goal is to maximize the serviceability of the system. The optimization result can be utilized to design controllers for the PV sources, loads and batteries. The proposed methods are tested on a Ring-Bus system. The testing result shows that the system can correctly determine its optimum operating strategy and corresponding control actions.