Resumo:
The accurate knowledge of the solar cells parameters dependence on irradiance and temperature is of vital importance for the performance assessment of photovoltaic modules
and development of new devices. Many works have been published so far to understand
the aforementioned dependence, but significant discrepancies have been found. Therefore,
in order to clarify these discrepancies, the temperature and irradiance impacts on seven
polycrystalline silicon solar cells were studied through a minutious experimental characterization in the range 600-1000 𝑊/𝑚2 and 25-55oC, using a solar cell characterization
platform equipped with vacuum chunk and temperature control, developed during this
work, and posterior computational extraction of the single diode parameters using the
Differential Evolution optimization technique, resulting in a very low fitting error between experimental and simulated I-V curves. The results indicated that the temperature
effects are stronger for all the single diode parameters except for the photocurrent. Series
resistance was found to be better described by an exponential decrease with increasing
temperature, remaining almost constant as irradiance changed. Shunt resistance showed
a linear decrease for increasing temperature, and remained almost constant for different
irradiances. The diode saturation current exhibited an exponential increase for higher
temperature values and remained almost unchanged for increasing irradiance. The diode
ideality factor remained almost unchanged for both temperature and irradiance changes.
The photocurrent showed a linear increase for both temperature and irradiance increase,
but it was much more accentuated for the latter. Also, it was observed that the errors and
uncertainties associated with the characterization procedure and parameter extraction
were small, so that the employed methodology produced results that can be regarded as
reliable representatives of the real behavior of polycrystalline silicon solar cells under the
temperature and irradiance range studied.
