Power Subsystem Summery - PDF document

1 Power Subsystem Summery Co nnection Diagram Power Generation The minimum power generation by 27% Efficiency Triple Junction solar panel will be ab out 3.8 watt. As shown in the following graph which is plot of average power generation over a year. Power graph for sun pointing Losses at SMPS stages of more than 90% efficiency  Battery Charge Regulators (BRC),  Bidirectional power and c harger  3.3 or 5 volt REG This makes useable power = 0.9*0.9*0.9*solar flux = 0.9*0.9*0.9*6.8 = 4.957 watt The consummation by reaction wheels will go up but still it is better. 2 Power Budget Component Name Model Name Manufacturer Standby Power Avg Power Max. Power Voltage Supplied Duration (Watts) (Watts /orbit) (Watts) (Volt) (1 orbit ~ 100 mins) On - Board Computer 1 FM430 Flight Module Pumpkin 0.00001 0.017 0.025 5 100 Receiver Module In - house development around ADF7020 - 1 IIT Kanpur 0 0.087 0.1 3.3 2.5 Beacon Module In - house development around MAX1472 IIT Kanpur 0.0056 0.18 0.3 3.3 100 Magnetometer HMR2300 - D00 - 232 Honeywell 0.24 0.243 0.32 7.5 100 Temperature Sensor LM355M 0.05 0.05 0.05 3.3 100 Magnetorquer In - house development IIT Kanpur 0 0.6 0.8 3.3 50 Power Drawn by Board 1 1 U EPS 1.177 1.595 On - Board Computer 2 Atmel SAM7X processor Custom 0.01 0.6 1 3.3 100 Transmitter Module Custom make with CC1070 and RF5110G IIT Kanpur 0.01 0.06 2.4 3.3 2.5 Reaction Wheel Custom (EC 20 FLAT) 351099 Maxon Motor and drive 0 0.18 2.85 7.5 6.8 Micro GPS Receiver GPS 600 GPS Creation and ARM7 based 0 0.26 1 5 26 MEMS IMU MEMS Accelerometer and gyros IIT Kanpur 0 0.16 0.6 3.3 43 Camera In - house development around Lupa - 300 Cypress Semiconductors 0 0.05 0.3 3.3 1.5 Power Drawn by Board 2 3 U EPS 1.31 8.15 Total Power Drawn 2.487 Total Power Drawn with 10% margin 2.7357 3 Duty Cycle Graphs for a day (14 orbits) Power Board 1 ( Space proven section ) Power in Watts vs time in minutes Power Board 2 (Experimental section) Power in Watts vs time in minutes 4 Energy Balance The tentative energy balance worst case calculation is as follows - Power Board losses (three SMPS stages) = 90% * 90% * 90% Effective solar cell efficiency= 24% at 80˙ C (as suggested) Solar power= 0.1280watt/cm 2 Unit c ell area= 30 cm 2 Battery nominal voltage= 3.72*2 =7.4V Battery capacity= 2AHr (charging cut off for individual cell= 4.1V) Charge Discharge Efficiency= 99.9% Energy in joule vs Time in minutes (Better picture of change in events can be obtained from nex t graph) Duty Cycle Graph for power board 2 The Power consumption and solar power generations are shown below Power (Watts) vs Time (minutes) (There are equally spaced fourteen 37minutes shadow regions and four Ground passes activities of ~24 minute e ach) Ground station tracking time consists of 15 minutes of reorienting and stabilization time was 8.75 minutes of communication is done. ( On average)