Impact of partial shading on voltage- and current-based maximum power point tracking of solar modules

Detailed theoretical analyses are presented to show the influence of partial shading on v-i and p-i characteristics of solar modules and to compare the accuracies of two simple, fast and reliable maximum power-point tracking (MPPT) techniques for photovoltaic (PV) systems: the voltage-based (VMPPT) and the current-based (CMPPT) approaches. Simulations are presented to highlight impacts of partial shading on MPPT of individual and series connected solar cells without and with the bypass diodes. A modified CMPPT approach is proposed to integrate partial shading. Results show considerable increase of captured maximum power compared with the conventional CMPPT, VMPPT and P&O tracking methods.