PEAK BRACKETING AND DECREMENTED WINDOW-SIZE SCANNING-BASED MPPT ALGORITHMS FOR PHOTOVOLTAIC SYSTEMS

摘要

This paper presents a peak bracketing algorithm and a decremented windows- size scanning-based algorithm to trace a maximum power operation point of a solar array in photovoltaic systems. Power curves of the systems can contain some local maximum power points, besides a global maximum power point (MPP). This problem appears due to the existence of partial shadows or non uniform solar irradiance on the photovoltaic panel surfaces. Atmospheric condition changes (irradiance and temperature changes) can also change the power curves and MPP locations on the curves. Three types of the iterative scanning-based MPPT algorithms are proposed to solve the partial shading problem and the changes of power curves, i.e., decremented window scanning, peak bracketing (PB) method and PB with initial scanning. The simulation results have presented that, for some cases, those MPPT algorithms can find out the global maximum power points (MPPs) of the partially shaded photovoltaic system with relatively smaller number of perturbing-and-observing (P&O) steps. The proposed algorithms can significantly outperform a traditional hill-climbing method in terms of the number of required P&O steps to reach the global MPP.