Remedyto the Shading Effect on Photovoltaic Cell

Abstract

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 proposes methods to enhance the PV system efficiency and robustness under partial shading. Here, bypass diodes are connected parallel to a number of solar cells. Under normal operating conditions, the diodes are blocked compared to the voltage generated by the cells. When shading occurs, the reverse of the voltage was observed in that specific section which enables the bypass diode in parallel to conduct the current. It was observed that; the current of the un-shaded flows through the bypass diode and the power/voltage characteristics shows a second local maximum. Also, the shaded cell was only loaded with that fraction of power produced by the un-shaded cells of that section.