Simulation and analysis of variable step size P&O MPPT algorithm for photovoltaic power control

The Maximum Power point Tracking Controller (MPPT) is an essential part of the photovoltaic (PV) system, it is used to extract the maximum power from the photovoltaic solar module and transfer that power to the load. Several MPPT techniques have been proposed in the literature. One of the most commonly used techniques is the perturb and observe algorithm (P&O), due to its low cost and simple implementation, but it suffers from the slow tracking speed for small step of perturbation and oscillations around the maximum power point (MPP) when it is subjected to a large step. In this article, the P&O algorithm with a variable step size (VS_P&O) is simulated by the PSIM software, analyzed and compared with the fixed step size P&O technique (FS_P&O). These two techniques are also simulated with and without proportional integrator corrector (PI corrector). The results show the good tracking, the high efficiency and precision of the VS_P&O technique using the PI corrector.