The function of the power system is to generate power by solar cells and store in batteries.
Also provide stable power to other subsystems is a role.
For this aim, system configuration power budget and on board components has been designed and selected.
SYSTEM BLOCK DIAGRAM
Power system concept is as followed.
Batteries provide power to satellites during eclipse.
Commercial use Mn Liion secondary batteries are selected.
Several space environment tests have been done to check the works of the batteries at space.
During daylight, solar cells provide power to other subsystems and charge batteries.
Solar cells are body mounted on CubeSat's 6 panels.
Silicon solar cells are considered to use.
POWER REGULATION AND CONTROL
Provide regulated dc power to each subsystem.
The aim of convert efficiency is 80%.
Charge circuit monitors and controls energy charge to Liion batteries by solar cells.
The aim of charge efficiency is 80%.
XI-I POWER SYSTEM
XI-II functional block diagram is as follows.
XI-I power system board is made as following picture.
Solar cells are arranged on one surface.
XI-II Power System
There are several upgrades for XI-II power system.
XI-II Power System is designed as followed
The PCB, which has been made is
Supply 5V for electronics subsystem and communication subsystem, 10V for a transmitter.
Electronics and communication subsystem monitor consuming current each other and shutdowns power supply if it detects SEL.
Solar cells generate power, drive CubeSat and charge batteries.
Nominal voltage is 5V (Except a MTQ and a transmitter)
Modification from XI-II:Solar cell connectors and ammeters are mounted on Structure system and downsize power board.
XI-II ALPHA power system PCB is
XI-II GAMMA uses switching regulators instead of DCDC converters to improve regulation
efficiency. Other functions are the same as XI-II
XI-II GAMMA power system PCB is
XI use Lithium ion secondary batteries
Manganate Lithium ion secondary battery
Capacity 780mAhr , 8 batteries are in parallel
XI can be driven for 40 hrs only by batteries
Solar cells are made in SHARP.
They generate 1200mW(AVE.)
Cell arrangements are as follows.
Solar panels are not mounted on XI-II.
Training for arrangement of cells.
Charge and discharge sham cycle tests on orbit.
XI-II Magnetic system
Attitude is controlled using magnetic field.
Smooth thermal input
Point antennae to the ground station
A permanent magnet and a magnetic torquer align CubeSat magnetic dipole moment with earth magnetic field.
And a libration damper absorbs vibration in order to stabilize attitude change.
Attitude change can be measured by solar cells output currents. (during daylight)
XI-III Power System
Almost all componets are made of flight model.
True power consumption will be measured.
XI-III Magnetic System
To cut down power consumption, A MTQ will not be equipped. A permanent magnet and a libration
damper will be used.