Abstract

The scope of this thesis is the study and the measurement of a solar panels’ power curve, in low cost and appropriate technology applications. In this framework, measurements are conducted for the determination of the IV characteristic curve and other features of a solar panel in outdoor field tests at the roof of the Electrical and Computer Engineering department of the National Technical University of Athens.

Initially, the structure of polycrystalline silicon solar cells is described, and their dependence on variables such as irradiation, ambient temperature, partial shade, saturation current, series resistance and shunt resistance. This study is made more complete with the addition of experimental results. In this process the factors that influence the photovoltaic operation are analyzed at great length in a real installation. It is also a comparison is made between experimental data and the data produced through simulations.

Additionally, the maximum power point of a solar panel is investigated to which the photovoltaic panels attribute their maximum power. Three DC/DC converters are examined, as well as the operating principles of MPPT algorithms with special analysis in Pertrube and Observe(P&O). Moreover, there is an analysis and design of a DC/DC buck converter, which is controlled from a microprocessor, in this case an Arduino microprocessor, in order to charge a 12V battery bank.

Finally, results are presented associated with the power production of photovoltaic panels when connected to a MPPT DC/DC buck converter. The power produced is compared between direct battery connection and MPPT DC/DC buck converter connection, resulting in the production of up to 10% more energy. Experimental results show the voltage and current rippling at the output and input of the converter circuit respectively.

Keywords: photovoltaic panel, solar irradiation, low cost applications, appropriate technology, acquisition system, IV characteristic curve measurement, temperature, tilt angle of the solar module, DC/DC buck converter, algorithm P&O, microprocessor, battery

Author: Alexia Kapetanaki

Responsible PhD: Kostas Latoufis / latoufis@power.ece.ntua.gr

Supervising Professor: Nikos Hatziargyriou / nh@power.ece.ntua.gr

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