Evaluation of maximum power point tracking methods for grid connected photovoltaic systems

This paper presents a study of two maximum power point tracking methods for grid connected photovoltaic systems. The best operation conditions of the perturbation and observation and the incremental conductance are investigated in order to identify the performances of photovoltaic systems. Improvements of these methods can be obtained with the best adjustment of the sampling rate and the perturbation size. Practical considerations about the incremental conductance are discussed and some modifications to overcome its problems are done. A procedure to determine the parameters is explained and it helps to define which method is better to the grid connected photovoltaic system with only one conversion stage. The methods influence the quality of the currents injected in the grid and this influence becomes the main parameter for choosing the incremental conductance. The improvement with the choice of the best parameters is proved by means of simulation and experimental results.