Abstract
ABSTRACT
The output power induced in the photovoltaic (PV) cells is influenced by the intensity of the solar radiation, the temperature of the solar cells and the load connected to the solar panels. Therefore, to make PV cells keep giving maximum power under different operating conditions, a Maximum Power Point Tracking (MPPT) strategy is required. The Fuzzy logic controller (FLC) is one of most sufficient control strategies used for MPPT. FLC based on linguistic rules describing the operators control strategy is applied to control the step-up converter for MPPT. The proposed PV system designis evaluated and tested by computer simulations, using Matlab/Simulink facilities. Practical implementation is also included in this study. The fuzzy based MPPT algorithm is written in assembly language using the fuzzy logic instructions supported with the microcontroller HC12 MCU. Simulated and practical results are presented under different operating conditions in order to determine the tracker efficiency. The MPPT has been tested with three -, five- and seven-terms of linguistic variables for each input/output fuzzylabel. The tracker efficiency is about 92% using three fuzzy subsets with some fluctuation and about 95% using five fuzzy subsets with less fluctuation. By using seven fuzzy subsets, the tracker efficiency amounts to 99.9% and the system seems to be extremely stable with minimum fluctuation.
Keywords: Fuzzy Logic, Photovoltaic, MPPT
