19-04-2012, 05:19 PM
Modelling of Photovoltaic Module.
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Introduction
The increasing interest for renewable energies is due to
the world conscience of revising the energy policies, in
order to fight against the emissions of CO2. Some
proposals to achieve this goal are: substitute the fossil
fuels for cleaner energies, limit the damages in the
environment and in the ecosystem, as well as incentives
to develop alternative resources.
The photovoltaic energy is a clean energy, with a long
lifespan and a high reliability. So, it can be considered as
one of the most sustainable of the renewable energies.
These systems can be located in or near where the
necessity takes place, avoiding losses of transmission and
contributing reductions to the CO2 emission in urban
centers
Photovoltaic cell
The solar cell is the basic unit of a photovoltaic module
and it is the element in charge of transforming the sun
rays or photons directly into electric power.
The solar cell used is the PN union, whose electrical
characteristics differ very little from a diode, represented
Model programming
The created model has been based on previous studies
like for example developed by G. Walker [2], Akihiro Oi
[7] and F.M. González-Longatt [8].
The function developed by all authors is very similar.
This function is based on Matlab Software, which needs
three values to calculate the net current of the cell
(Module operating current):
Photovoltaic Module
Because in the real operation of the solar cell some losses
exist, they have been added to the model as a resistance
in series (Rs) and another in parallel (Rsh) to get a more
real behaviour and to pick up these losses.
Conclusion
In this paper, different models have been compared to
analysing the performance of solar cells.
The developed model, with electrics main parameters, is
valid for I-V characteristics measured and can work with
few parameters of input demonstrate to graph and
numerically the operation of a solar model.
The objective is develops in the future a complete model
to simulate the electrical behaviour of the PV systems.
And to develop, starting off of these models, other
models, but in this case in Simulink.