The non ideality effect of optimizing the P&O MPPT algorithm for PV battery charger applications

Maximum Power Point Tracking (MPPT) techniques are used in photovoltaic (PV) systems to maximize the PV array output power by tracking continuously the Maximum Power Point (MPP) which depends on panel´s temperature and irradiance conditions. The perturb and observe (P&O) MPPT algorithm is the most commonly used method due to its ease of implementation. But it has some drawbacks such as the oscillation of the operating point around the MPP at steady state which consumes a portion of the available energy. Also, the P&O algorithm can be confused by rapidly changing atmospheric conditions that can lead into unstable system. In this paper, the P&O MPPT parameters are optimized to the dynamic behavior of the PV system in order to limit the negative effects of the above drawbacks. Theoretical analysis is done for non-ideal dc-dc converter connected to battery charger to obtain the optimal choice of two main P&O algorithm parameters. These parameters are the amplitude of the duty cycle perturbation and the sampling interval. Also the study is compared with the analysis of the ideal dc-dc converter in order to clarify the effect of non-ideality on the parameters design. Finally, both simulation and experimental results are presented to validate the theoretical analysis.