Development of an advanced nano-satellite (VELOX-I) - power management system

• Main Author: Hong, Charlin Zhanlin.
• Other Authors: Low Kay Soon
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/53040
• Institution: Nanyang Technological University

The objective of this Final Year Project is to develop and enhance the current Power Management System (PWRS) of the nano-satellite, VELOX-I, which is being developed by the Satellite Research Centre of Nanyang Technological University. The function of the PWRS is to manage and distribute power to the other subsystems efficiently. This is analogous to the function of a heart in the human body. Therefore, an efficient PWRS would ensure a ‘healthy’ and successful operation of the satellite. The PWRS is made up of three main modules, the solar array module, the battery management module and the power distribution module. Among the three modules, the battery management module will be the focus of this report. Power is generated from the solar array module and supplied to the battery management module which consists of three boost converters with MPPT function, a battery protection circuit and a 2-cell Lithium-ion battery pack. The MPPT ensure that maximum power is always extracted from the solar arrays. This project includes optimising the boost converter circuit, developing and implementing Maximum Power Point Tracking (MPPT) technique into the PWRS. Performance studies had been done for two MPPT methods namely, Perturb & Observe (P&O) and Incremental Conductance (InC) to select the most appropriate MPPT method for PWRS. Experimental results shows that INC have better efficiency when compared to P&O in various test conditions, and thus has been selected to be implement in the PWRS. The efficiency of InC was proven to be higher than the P&O by as much as 4.94% and the results also proved that InC performs better than P&O for all tested step size under non-varying condition. The author had also developed an enhanced EEPROM function which uses a software redundancy approach. With this implementation, the satellite is now able to detect the error in the EEPROM and rectify it. This enhanced EEPROM function had not only been implemented in the PWRS, it had also been implemented in the other subsystems as well.