A Comparison Analysis between a Fixed and Multi-Step Size MPPTs for PV System under Variable Irradiance and Real Solar Curve

Abstract

The control of the power electronic interfaces is essential to ensure the high efficiency of the photovoltaic system. In a DC stand-alone photovoltaic system, the boost converter is the most used. A regulator named maximum Power Point Tracking (MPPT) is inserted to control the ON/OFF states.  Incremental conductance (In-Cond) is widely used to extract the maximum power point (MPP) from the Photovoltaic panel. It presents more efficiency and reliability compared to the conventional perturb and observes (P&O) technique. However, it presents power loss during the variations appearing during changes in weather conditions, due to the use of fixed step size. Accordingly, the present paper proposes a Multi-step size In-Cond to adapt the PV system to any change of the applied irradiance and to overcome the drawbacks of the existing In-Cond. Indeed, the present contributions introduced   two-steps sizes instead of one. The principle is to design a step size value when approaching the MPP and a large value when the operating point is far from the MPP. Simulations and comparisons through MATLAB/Simulink under various applied conditions show that the proposed technique outperforms the conventional Inc-Cond in terms of convergence speed, response time, stability, and performance.