A new voltage equalization based distributed maximum power point extraction from a PV source operating under partially shaded conditions

Abstract

The power-voltage and current-voltage characteristics of partially shaded photovoltaic modules with bypass diodes in a string typically exhibit multiple peaks (global peak and local maxima peaks) and multiple steps respectively. Due to this, conventional maximum power point methods are unable to track the global Peak. Bypass Diodes are connected across each Photovoltaic Module to prevent a large voltage appearing across it during partially shaded conditions. This paper presents a new circuit based on SEPIC configuration for compensating the power to shaded PV modules in a String. This configuration has only one switch and the control complexity is less as compared to existing configurations. The proposed configuration equalizes the voltage across each PV Module in a string by operating each PV module close to their maximum power point. The effectiveness of the proposed system is investigated and confirmed for partially shaded PV Modules in a string. All the analytical and simulation results are included.