Comparative Evaluation of Maximum Power Point Tracking Methods for Photovoltaic Systems

This paper presents a study of two maximum power point tracking methods for grid connected photovoltaic systems. The best operation conditions for the perturbation and observation and the incremental conductance methods are investigated in order to identify the efficiency performances of these most popular maximum power point tracking methods for photovoltaic systems. Improvements of these methods can be obtained with the best adjustment of the sampling rate and the perturbation size, both in accordance with the converter dynamics. Practical aspects about the incremental conductance method are discussed, and some modifications are proposed to overcome its problems. A procedure to determine the parameters is explained. This procedure helps to identify which method is better suited for grid connected photovoltaic systems with only one conversion stage. The methods' influences on the quality of the currents injected in the grid are evaluated and compared. The performance improvement achieved with the choice of the best parameters is proved by means of simulation and experimental results performed on a low power test system. The simulation results have been obtained by modeling a photovoltaic system in MATLAB. A simplified model was used that employs only parameters of interest and therefore decreases simulation time. Experimental results corresponding to the operation of a grid connected photovoltaic converter controlled with a digital signal processor have been obtained. [DOI:10.1115/1.3142827]