Electric power supply
One of the most critical units of the TTÜ100 cubesatellite is its power supply (EPS – Electrical Power Supply). This board has to deliver uninterrupted and stabilized supply (+5V) to all the subsystems of the spacecraft.
In odrer to do this EPS converts Solar energy harvested by solar panels into electricity which is stored in Li-Ion batteries. Our satelliite has 9 solar panels: 5 on sides (except lower side looking most time to Earth) and 4 panels on „wings“. A total of 7,5W can be harvested in case of good exposure to Sun light. Maximum Power Point Tracking technology is used to increase conversion efficiency.
The spacecraft will be launched to low-Earth orbiit (about 600km) and spends 2/3 of one orbit in Sunshine. Dark periood lasts about 30 minutes.
In order to increase reliability critical units of the EPS are duplicated.
EPS monitors constantly its state and is capable of transmitting all telemetry info to Ground station independantly (without commands from on-board computer).
Firmware of the EPS is upgradeably remotely (from Ground Control.
EPS is capable of providing electrical power to ohter subsystems of the spacecraft even in case of its microcontroller failure.
The image shows 3 "generations" of EPS