Power Supply System
- Power Control Unit des BEESAT-2
- © TU Berlin
The cubical satellite is equipped with triple-junction gallium-arsenide (GaAs) solar cells on all sides. These solar cells provide an efficiency of 26.8%. The solar generator consists of parallel strings of two cells in series. Each string is protected by a Schottky bypass-diode. The solar generator powers the redundant battery charge regulators. The satellite is equipped with two physically separated lithium-polymer batteries that are sealed with epoxy resin and stowed in an aluminum compartment to protect them from the vacuum of space. Each battery is designed for a nominal lifetime of one year, providing a nominal voltage of 7.4V and a capacity of 1250mAh.
The chosen design of two separated, hot redundant power supply chains is able to tolerate outages of one system without putting satellite operations at risk.
A power control and distribution unit (PCU) supervises battery charging and power consumption of 20 individually switchable components on board the satellite. Those components are powered by a regulated power bus of either 5V or 3.3V.
The PCU is protected by security measures embedded into the operating software and by external securing circuitry. Radiation induced effects can thus be handled effectively.
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