Rachid
1
Darbali ,
John E.
1
Salazar ,
Nicolas
1
Cobo
Dr. Eduardo I.
1
Ortiz ,
Dr. Amilcar A.
2
Charris
1Department
of Electrical and Computer Engineering, University of Puerto Rico-Mayagüez, Mayagüez, Puerto Rico 00682, USA
2Department of Mechanical Engineering, Inter American University of Puerto Rico-Bayamon , Bayamon, Puerto Rico 00957, USA
I. Introduction
III. Standard Testing
IV. Thermal Testing
CubeSat’s are cube shaped micro scaled satellites of low
mass and size targeted at performing a wide range of
tasks, such as collecting and transmitting data [1]. They
are composed of an onboard computer, electronic
power supply (EPS), control and communication
systems. This project presents an EPS designed for the
power management for a CubeSat. It is designed for
higher efficiency, utilizing high-performance GaAs solar
panels and DC/DC converters in combination with a
MPPT technique to improve the power extraction and
further increase efficiency. Fig. 1 shows a standard 2U
CubeSat design.
The design consists of Gallium Arsenide (GaAs) solar panels, a
SEPIC tasked with performing the MPPT, a battery that
provides storage and two Buck converters that function as
voltage regulators that will supply the necessary 3.3V and
5.0V for the CubeSat payloads. Fig. 3 illustrates the developed
CubeSat EPS.
Fig. 4 illustrates the
obtained results from
measuring the MPPT,
2cm
3.3V and 5.0V voltage
regulators. Notice how at
9cm
9cm
varying solar irradiance
conditions, the MPPT
algorithm is able to
Fig. 3. The Puerto Rico CubeSat EPS
extract
the
utmost
Subsystem prototype.
available power.
At varying payloads, the EPS voltage regulators are able to
maintain the required power output.
A thermal image is developed to identify which
components overheat when the EPS is in operations [2].
Fig. 5 and Fig. 6 illustrate the thermal tests performed
at high and low temperatures respectively.
Payload
Attitude
Determination
Control
Onboard
Computer
Electronic
Power Supply
Communication
Solar
Panels
P Experimental
Fig. 5. Results for High temperature thermal testing at 80°C.
P Theoretical
Power (W)
8
6
400W/m2
4
200W/m2
2
0
Antenna
600W/m2
1200W/m2
1000W/m2
0
10
800W/m2
20
30
Time (sec)
40
50
60
Fig. 6. Results for Low temperature thermal testing at -30°C.
(a)
P Experimental
Fig. 1. A standard 2U CubeSat.
4
4
3
2
3
2
1
1
0
0
V. Conclusion
P Calculated
5
Power (W)
The EPS is a critical subsystem in the CubeSat design.
This subsystem is tasked with supplying electricity to
the CubeSat’s payloads by maximizing the available
electrical energy generated. Fig. 2 shows a block
diagram for the proposed EPS.
5
Power (W)
II. Methodology
P Experimental
P Theoretical
0
0
10
10
20
20
30
40
30Time (sec) 40
50
60
50
70
60
70
Time (sec)
(b)
P Experimental
P Experimental
PPCalculated
Theoretical
5
The design of an EPS for a CubeSat is demonstrated.
This design consists of: a SEPIC that performs the MPPT,
and two Buck converters that function as voltage
regulators that will supply the 3.3V and 5.0V voltages.
Results indicate that the utmost available power from
the PVM array can be extracted using the optimal duty
ratio MPPT method. Results also illustrate that the EPS
can supply 3.3V and 5.0V voltages.
6
Power (W)
Power (W)
4
3
2
References
4
2
1
0
0
0
0
10
10
20
20
30
40
30 Time (sec)40
50
60
50
70
60
Time (sec)
(c)
Fig. 2. CubeSat EPS block diagram.
Fig. 4. CubeSat Experimental results. (a) MPPT.
(b) 3.3V voltage regulation. (c) 5.0V voltage regulation.
70
1. R. Darbali-Zamora, E. I. Ortiz-Rivera and A. A. Rincon-Charris, "The
Puerto Rico CubeSat project to attract STEM students into the area of
aerospace engineering," 2015 IEEE Frontiers in Education Conference
(FIE), El Paso, TX, 2015, pp. 1-7.
2. R. Darbali-Zamora, D. Merced-Cirino, J. Rivera-Alamo, E. I. Ortiz-Rivera
and A. A. Rincon-Charris, "Design and thermal testing of a Power
Supply prototype for the Space Plasma Ionic Charge Analyzer (SPICA)
CubeSat," 2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC),
New Orleans, LA, 2015, pp. 1-6.