ELECTRICAL POWER SUBSYSTEM (EPS)
The electrical power generation and distribution (PGD) system of satellite is responsible for generating and supplying power for the satellite and payload. The PGD system is described using fundamental blocks: power generation, energy storage and power management (distribution, regulation and control).
Why we need EPS ?
The Power Generation and Distribution System is a huge task which requires designing the system to ensure that it satisfies all of the satellite requirements. The main functions of electrical power subsystem are:
· To supply a continuous source of electrical power to the satellite loads during the mission life.
· To charge batteries and store excess power available.
· To supply sufficient power to other subsystems as per demands.
· To monitor condition of each load and switch off load if it is malfunctioning or not in use.
· To store all voltage, current and temperature values indicating health of power system and relay information to OBC.
· To power – up the satellite upon ejection
DESCRIPTION
Solar energy received from the solar panels is used to power the system during the sun-on periods and to recharge the battery –pack for sun – off periods through photovoltaic GaAs solar cells. During the solar eclipse periods the battery(secondary) is used as primary source .The main power line (connected to solar array and battery) feeds into a number of DC-DC converters, which provides the required voltage for the satellite’s onboard electronics. A battery monitor is also integrated into the system to monitor sustainable power consumption and manage the power. Specific components selection and circuit design is dependent on several factors like system payload,electronic and hardware specifications.
PHASES INVOLVED
During this satellite project Electrical power subsystem will evolve through these phases:
- Designing
o Designing and fabrication power modules namely: power generation unit, power storage unit, power management unit (containing power distribution, regulation and control units).
- Simulation and testing
o Simulation and testing of electrical circuits of power modules for different conditions.
o Testing of power subsystem such as: thermal, shock, Vacuum chamber test.