Effect of Shading on Photovoltaic Cell

Abstract

Photovoltaic (PV) power systems have been widely applied in commercial and domestic facilities. Electrical Energy Storage (EES) systems are mandatory in standalone PV systems for continuous power supply. In this paper the efficiency and robustness enhancement methods for PV systems under partial shading have been investigated. Partial shading due to moving clouds and shadows of nearby obstacles on the PV module array causes significant efficiency degradation, since shaded and non-shaded PV modules have large discrepancy in their maximum power points. Use of bypass diodes for each PV module may mitigate the negative effect from partial shading. However, this method alone may still face severe energy efficiency degradation caused by the energy loss due to parasitic effects in the EES elements under variable incoming power from the PV modules. Hence, this paper investigates the effect of shading on photovoltaic cells.