Development of an advanced nano-satellite VELOX-II solar energy system (concentrated photovoltaic)

Space has always been one of the primary concerns for many systems, and a challenge faced by many in developing continuously smaller and yet higher efficient energy harvesting system. This thesis reports a new energy harvesting system designed for the nano-satellite developed by the Satellite Research Centre of Nanyang Technological University (NTU). Developing a small energy harvesting system for a nano-satellite is evitable since the allowable dimension is constrained. The mass is also another consideration as the cost of launching a satellite into space is dependent on the mass. Through saving the space and mass, additional payloads can be implemented in the satellite making efficient use of the system. This project aims to develop a highly dense energy harvesting system to advance the current Photovoltaic system used by the typical nano-satellite. The energy harvesting system can also potentially be implemented onto a high altitude balloon that both Google and Facebook are adventuring. In this report, Concentrated Photovoltaic cell (CPV) would specifically be studied and implemented into a nano-satellite power system. Although the CPV cell is able to generate more energy as compared to conventional PV cells, one of the drawbacks is the additional lens required for focusing solar energy onto the cell. In addition, the high concentration of solar energy would also cause significant increase in the temperature of the cell, and potentially reducing the efficiency of the power system as well as damaging it. Hence, this report focuses on optimizing the power generation through altering the focusing distance between the lens and the cell, and the temperature of the cell. This study also includes the development of a MPPT module to optimize the power harvesting from the CPV cell, and a battery management module to protect the batteries from overcharging and inrush current. The experimental results from the investigation conclude that the power generated from the CPV power system is more than twice the amount generated from the current PV power system for a given area, and hence can potentially be used for a near future nano-satellite.Bachelor of Engineerin