Simulation, design and implementation of various MPPT systems for micro cube-satellite application

Abstract

This paper discusses the Maximum Power Point Tracking (MPPT) system developed for Electrical Power System (EPS) of COEP Satellite Initiative's second satellite mission. Primary scientific objective of the mission is orbit raising using solar sails with radiation monitoring data collection. This mission has higher energy requirements as compared to first mission, Swayam, this necessitated the implementation of MPPT along with deployable solar panels. The MPPT system which connects to Li-ion battery also functions as battery monitoring and protection system (BMPS). BMPS designs are also examined. The MPPT controller controls switching of a DC-DC converter based on SEPIC topology. This topology provides flexibility in solar panel and battery pack configurations as the input can be higher or lower than output voltage making the design generic along with utilisation of all operating points. An integrated system including solar array, MPPT controller, SEPIC converter and battery pack is simulated in SIMULINK of MATLAB which facilitated tuning and optimization of critical parameters. Various algorithms considered for MPPT are evaluated in brief of which-‘Perturb and Observe (P&O)’ is discussed in detail. Design and limitations of many commercially available ICs are discussed. Various design techniques for implementing MPPT on controller have also been discussed.