An Intelligent Control System Used to Improve Energy Production From Alternative Sources With DC/DC Integration

A fuzzy P+I and a classical proportional-integral (PI) controllers for charging and discharging of a battery pack connected to a photovoltaic (PV) array are described. To maintain the PV array operating as close as possible to the maximum power point (MPP) a perturb and observe (P&O) algorithm along with a classical PI controller to regulate the terminal voltage of the PV array are also investigated. The power electronics interfaces used to keep the PV array operating close to the MPP and to manage the charging and discharging of the batteries are the step-up and bidirectional buck-boost converters. On the other hand, the interface to the grid consists of a voltage source inverter (VSI), which controls the power injected into the grid and regulates the DC-link voltage. The DC-link voltage is also controlled by a fuzzy P+I or classical PI controllers, which are used to promote the power balance between the DC-link and grid and to determine the amount of current and, consequently, power absorbed by or injected into the grid. Simulated and experimental results under different conditions are presented to demonstrate the effectiveness of the proposed approach.