High efficient variable step size incremental resistance maximum power point tracker for PV battery charging applications

The stability analysis of the adaptive variable step size MPPT algorithms is extremely depending on the value of the scaling factor (N), which typically adjusts the input signal to a proper magnitude prior to determine the proceeding step size. This paper proposes a new small signal analysis of the variable step size incremental resistance INR MPPT algorithm used in photovoltaic PV battery charging systems. The contributions in this paper are: first, setting up the overall small signal model of the PV system. Second, designing the appropriate value of the scaling factor (N), that ensures a satisfactory dynamic response and an accurately steady state performance without any oscillations. The simulation and experimental results indicate the feasibility and the improved functionality of the tracking system.