Rachid Darbali-Zamora and Dr. Eduardo I. Ortiz-Rivera
rachid.darbali@upr.edu and eduardo.ortiz7@upr.edu
Department of Electrical and Computer Engineering,
University of Puerto Rico-Mayagüez, Mayagüez, Puerto Rico 00682, USA
I. Introduction
III. Simulation Results
Space stations are spacecrafts with the capability of
allowing crew members to remain for prolonged
periods of time as the spacecraft orbits the earth [1].
They are mainly powered by solar panel arrays that
transform available solar power into energy which is
then stored in batteries for later use. This energy is
distributed along the space stations payloads. Fig. 1
illustrates the main components that compose a space
station.
This simulation uses an exponential analytical mathematical model to represent the PVM arrays behavior [3]. In addition, it
uses the state space average model to represent each DC/DC converter. The SEPIC is used to extract the utmost available
power from the PVM. The Buck-Boost Bidirectional converter charges and discharges the battery storage unto the DC link.
Fig. 1. The space stations components work like that of a
microgrid, employing power generation, storage, primary
loads and electrical vehicle integration.
Finally, the Buck converter is
used to provide regulated
voltage to the systems payloads.
Two Buck converters are used to
provide constant and varying
power consumption. Fig. 4
illustrates the power for the
PVM, battery storage, as well as
the constant power and variable
power consumption. Notice
from the simulation results that
during instances when the PVM
array is not able to supply
power to the loads, the battery
storage provides the required
power. Also, during instances
when excess power generated
by the PVM array, it is stored in
the battery storage.
Charging
Mode
(a)
Discharging
Mode
(b)
Varying Power Consumption
Constant Power Consumption
(c)
(d)
Fig. 4. Simulation Results. (a) Microgrids PVM Power Generation. (b) Microgrids Battery Power Storage.
(c) Constant Power Consumption. (c) Varying Power Consumption.
II. Methodology
IV. Details
V. Conclusion
The International Space Station (ISS) is the largest
functional space station to date. To power the space
station, solar panels are used as its primary energy
source. To offer a power solution during eclipsed
periods, battery storage is used as an energy
alternative [2]. Fig. 2 illustrates a simplified diagram of
the electrical power distribution system of the ISS.
The ISS uses nickel-hydrogen batteries to store energy to
provide power during eclipsed periods in orbit. For every 92
minutes that the ISS is in orbit, the battery storage provides
35 minutes of power. Fig. 3 the ISS orbiting pattern.
From the simulation results it can be noted that during
instances when the PVM array is not able to supply
power to the loads, the battery storage provides the
required power. During instances when excess power is
generated by the PVM array, it is stored in the battery
storage.
International Space Station
Eclipsed Region
Sunlight Region
800-1,200km
30min
1. M. Savoy, T. Miller; “International space station electrical
power system performance and operational lessons learned”,
Intersociety Engineering Conference in Energy Conversion
(IECEC’02), 29-31, July 2004, pp.93.
60min
Sun
Earth
Fig. 2. Diagram of the electrical power distribution system of
the ISS. The electric system is separated into generation
(blue), storage (green) and the DC link system (cyan).
References
Fig. 3. The International Space Station orbiting pattern at LEO. The
power distribution of the ISS coordinates between energy
generation and backup storage use.
2. M.J. Hart, R.J. Kinsey, A.S. Lee, J.S Yoshida, “International
Space Station life extension”, IEEE Conference in Aerospace,
pp.1-15, 6-13 March 2010.
3. R. Darbali-Zamora, E.I. Ortiz-Rivera, A.A. Rincon-Charris,
“Analytical Photovoltaic Mathematical Model with Varying
Inclination Angle for Satellite Applications”, IEEE Andean
Council International Conference (ANDESCON’16), Oct. 1921, 2016.