Inphase III, Implementation is the main task to be done, starting from the converters designed and simulated in phase II and, going through tests of these converters with the triple junction as input. MPPT using ANN has been done and results can be used to design the MPPT converter.For more advanced power system, single input single output converters can be exchanged with single input multi output converter which will decrease the space needed for the converters in a significant way.
The role of the power supply architecture of Qatar University Cubesat is supplying all the satellite subsystems by their power requirements. The architecture composes from different stages including power generation, storage and finally distribution. Different MPPT (maximum power point tracking) algorithm has been studied and compared with Perturbed &Observed (P&O) method that is designed by previous group, to compare the response of each technique under different conditions. in this project a new class of solar PV with three junctions is used. A prime mathematical model for triple junction PV has been developed and simulated under the effect of different parameters. H∞based closed-loop control is designed to control DC-DC converters and the design has been studied in terms of transient overshoot and steady state error and the results shows that how robust is the controller and it shows that it is the perfect choice for the CubeSat application.
The power supply architecture of the Cubesat was designed. Single PV solar panel has been modeled and simulated under different real space conditions including soft and hard shading. In addition to that, a primary modeling of triple junction PV solar panel has been done and simulated for various parameters such as irradiance and temperature. This is one of the major contributions of phase II. No such model is available in the literature and hence this is the novelty of the work. Results of triple junction model were compared to the results and data provided by Space Clyde to Qatar University and, it shows that the model is an appropriate one. For the maximum power point tracking, different algorithms studied including P&O which is modeled and tested during phase I and the conclusion of this comparison study is that ANN MPPT algorithm has fast and stable response compared to P&O algorithm. Based on this MPPT using ANN algorithm has been done for simulated data and practical readings. Moreover, H-∞ based closed-loop control is designed to control DC-DC converters and the design has been studied in terms of transient overshoot and steady state error and the results shows that how robust is the controller and it shows that it is the perfect choice for the CubeSat application.
The system configuration for the On-Board Electric Power Supply System (OBEPSS) can be well visualized as illustrated in figure 1
Power System Architecture for Qatar University Cubesat (Phase II) Abdelrhamn Abdalla, Abdallahi Ahmed, Abdulrahman Hussein and Moumen El-Hassan
Supervisors: Dr. Atif Iqbal & Dr. Ahmed Massoud Qatar University
Department of Electrical Engineering, College of Engineering Spring 2015
Introduction Practical Result
Abstract
Experimental setup
Future work
AcknowledgementsThe authors would like to thank their supervisors Dr. Atif Iqbal and Dr. Ahmed Massoud and the Department of Electrical Engineering in Qatar University. In addition, the authors would like to express their gratitude toward both Dr. Nader Meskin and Eng. Ben Pratheesh for their Help.
Conclusion
Figure 1. Hardware Overview of the power supply of the Cubesat
Figure 3. Neural Network Training Regression
Simulation Parameters of triple junction
Simulation Results
Figure 2. (a) I-V (b) P-V Curve for triple junction matched current density
System Overview
Mission StatementQatar university Cubesat (Qubesat) mission is to map and observe the current waste disposal sites in Qatar and search for the illegally disposed waste in the desert. To achieve that, a camera will be attached to the Cubesat to capture images of the desired sites.
BackgroundTo achieve this goal, the technical aspects of the project are performed through five different systems. The division is illustrated below.
The OBEPSS is responsible for delivering the power required to power the satellite efficiently. This process involves power generation through photovoltaic panels, power storage, power control, and power distribution to on board loads.The MECHS is responsible for designing the structure that houses the satellite equipments and protects it against vibration and extreme thermal changes in the low earth orbit (LEO).The COMS is responsible to assure a reliable communication (Uplink and Down-link) between the satellite and the ground station.The ACS is responsible for adjusting the position of the CubesatThe GSS is responsible for controlling the satellite and reviving the health of it in the space. In addition it receives the required data to achieve the mission of the satellite.
Table 1: Simulation Parameters of triple junctionParameter Value
InGaP Short Circuit Current ISC1 13.78 mA/cm2
GaAs Short Circuit Current ISC2 15.74 mA/cm2
Ge Short Circuit Current ISC3 20.60 mA/cm2
STC Irradiance GSTC 0.1W/cm2
STC Temperature TSTC 298 K
InGaPBandgap Energy 1.86eV
GaAsBandgap Energy 1.40eV
GeBandgap Energy 0.65eV
Cell Area 0.2663 cm2
Ideality Constant for all cells 2
Gamma γ (Sharp Cell) 2
Series Resistance 0.0134Ω
1 for cell 1α 5.771X10-4
2 for cell 2α 5.405X10-4
3 for cell 3α 4.774X10-4
Beta Constant β1 (Cell 1) 372
Beta Constant β2 (Cell 1) 204
Beta Constant β3 (Cell 1) 235
0 0.5 1 1.5 2 2.50
5
10
15
Voltage (V)
Curre
nt De
nsity m
A/cm2
I-V Curve of Triple Junction
InGaPGaAsGe
0 0.5 1 1.5 2 2.50
5
10
15
20
25
30
35
Voltage (V)
Powe
r W/cm
2
P-V Curve of Triple Junction
InGaPGaAsGe
(a) (b)
Table 2: Data used to test the network and output results
temp C 39.8 42.9
Irr. W/m2 868 1066.6
expected output voltage (V)
32.12 28.03
Output from ANN (V) 31.9 29.45
9.06 9.08 9.1 9.12 9.14 9.16 9.18 9.2 9.22 9.24x 104
23
24
25
26
27
28
29Controller Rejection
Time(10-4s)
Amplit
ude(m
V)
Figure 4. H-∞Controller Response
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