ABSTRACT:
The available power generated from a fuel cell (FC) power
plant may not be sufficient to meet sustained load demands, especially during
peak demand or transient events encountered in stationary power plant
applications. An ultracapacitor (UC) bank can supply a large burst of power,
but it cannot store a significant amount of energy. The combined use of FC and
UC has the potential for better energy efficiency, reducing the cost of FC
technology, and improved fuel usage. In this paper, we present an FC that
operates in parallel with a UC bank. A new dynamic model and design methodology
for an FC- and UC based energy source for stand-alone residential applications
has been developed. Simulation results are presented using MATLAB, Simulink,
and Sim Power Systems environments based on the mathematical and dynamic
electrical models developed for the proposed system.
KEYWORDS:
1.
Combined
system
2.
Dynamic
modeling
3.
Fuel cell (FC)
4.
Proton exchange
membrane fuel cell (PEMFC)
5.
Ultracapacitor
(UC)
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
 |
Fig.
1. Combination of FC system and UC bank.
Fig. 2. PCU and load connection diagram.
EXPECTED SIMULATION RESULTS:
Fig. 3. Real power of residential load.
Fig. 4. Variation of FC system output
voltage according to load demand.
Fig. 5. Variation of UC bank terminal
voltage according to load demand.
Fig. 6. Variation of UC bank charging
and discharging current according to load switching.
Fig. 7. Variation of ac output power.
Fig. 8. Variation of ac load voltage.
Fig. 9. Variation of modulation index
corresponding to load demand.
Fig. 10. Variation of ac voltage phase
angle.
Fig. 11. Variation of FC system dc
output power.
Fig.
12. Variation of hydrogen flow rate.
CONCLUSION:
A
UC-based storage system is designed for a PEMFC operated grid independent home
to supply the extra power required during peak demand periods. The parallel
combination of the FC system and UC bank exhibits good performance for the
stand-alone residential applications during the steady-state, load-switching,
and peak power demand. Without the UC bank, the FC system must supply this
extra power, thereby increasing the size and cost of the FC system. The results
corresponding to high peak load demand during short time periods are not shown
in order to simulate more realistic load profile. The load profile was created
by measuring data at 15-s sampling interval. However, the proposed model can be
used for different load profiles consisting of different transients and
short-time interruption. Also, it can be extended for use in many areas such as
portable devices, heavy vehicles, and aerospace applications. The lifetime of
an FC system can be increased if combined FC system and UC bank is used instead
of a stand-alone FC system or a hybrid FC and standby battery system.
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[1]
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[3]
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[4]
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[5]
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