Design of an MPPT charge controller using a DC–DC buck-boost converter under system disturbances

Abstract

This paper presents the analysis and design of a maximum power point tracker (MPPT) for a 6 KW photovoltaic (PV) system. The MPPT is implemented through a DC–DC buck-boost converter, modeled and simulated in MATLAB/Simulink. The design begins with determining the operating point of the system by establishing the relationship between the converter’s input impedance, output impedance, and duty ratio, which defines the mechanism of maximum power tracking under system disturbances such as variations in solar irradiance. To achieve optimal performance, the perturb and observe (P&O) algorithm is applied to track the maximum power point, generating a DC signal that is processed by a proportional–integral (PI) controller. The PI controller is designed using a mathematical model developed with the state-space approach, ensuring that the operating point of the system is maintained at the maximum power level.