Title:	Novel Semi-Empirical Combined Electro-Thermal Model for Solar Modules
Author(s):	B. Plesz, Z. Kohári, P.G. Szabó, A. Timár, G. Bognár
Keywords:	Solar Module, Electro-Thermal Model, Production Forecast
Topic:	OPERATIONS, PERFORMANCE AND RELIABILITY OF PHOTOVOLTAICS (FROM CELLS TO SYSTEMS)
Subtopic:	PV Modules
Event:	31st European Photovoltaic Solar Energy Conference and Exhibition
Session:	5AV.6.26
Pages:	2022 - 2026
ISBN:	3-936338-39-6
Paper DOI:	10.4229/EUPVSEC20152015-5AV.6.26
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Although there is a wide variety of models for power prediction there are only few models that combine electrical and thermal behaviour of modules and are capable of describing transient behaviour. This paper presents a novel, semi empirical combined electro-thermal model for solar modules. Inputs of the model are the electrical and thermal parameters of the module, and the data describing the ambient conditions. The model consists of three main sub-models. For the calculation of the light conditions from the meteorological data an adopted version of Bird’s clear Sky model is used. The irradiation value received from this sub-model is used in the thermal and the electrical sub-models. Both the electrical and the thermal sub-models represent new approaches in solar module modelling. The thermal model is based on a thermal RC ladder, which has the advantage that the thermal resistances and heat capacities can be determined directly by measurements (e. g. thermal transient measurement) or simulations of the solar module structure. This approach is universal, and can be utilized practically for all types of solar modules. Due to the incorporation of the heat capacitance into the thermal model the transitions between steady states can also be modelled. The electrical model is a semi-empirical model that utilizes the Lambert W function based solution of the single-diode model extended with series and shunt resistances. Since most solar cell types can be described with an exponential curve, this model approach can be regarded as universal. The temperature and irradiance dependence is described by temperature and irradiance dependent model coefficients (photocurrent, reverse saturation current, ideality factor, series and shunt resistance). These temperature and irradiance dependent parameters can be derived from I-V curve measurements obtained at different light intensities and temperatures under laboratory conditions or long-term outdoor I-V curve measurements. The other new approach of the electric model is that it delivers I-V curves instead of only giving an approximation for the maximum power or the efficiency, thus practically all important solar cell parameters can be derived from the model for any desired power point.