Simple solar panels/battery modeling for spacecraft power distribution systems

Abstract

To progress towards as quick as possible feasible pre-design of space missions, spacecraft early design today is organized gathering together experts from different spacecraft subsystems that share information (and results). This Concurrent Design (CD) approach needs accurate but quick solutions from all subsystems involved in each phase of that mission early design. At IDR/UPM Institute researchers have been working in simplified models for the spacecraft power distribution subsystem. In the present paper three models, for solar panels, the battery and DC-DC converters are described and tested with experimental data. The models were designed to be coupled within the simulation of a spacecraft mission. The model regarding the solar panels is focused on accurately estimate the power production from the panels, whereas the model of the batteries is based on the discharged energy rate as the main/control parameter instead of the discharged/charged ampere·hour rate. Finally, the solar-panels/battery coupled design is described in this paper, the UPMSat-2 mission being used as case study.