Partial Shading Effect on I-V Characteristic and Maximum Power of a Photovoltaic Array

Photovoltaic (PV) is a technology that can directly convert solar energy into DC electricity by using semiconductors. The performance of PV modules is highly dependent on solar irradiance and temperature. In practice, solar irradiance can be blocked by moving clouds, trees, other buildings, or dust that accumulates so that it will cast shadows on the PV module. If the sun's irradiance is blocked or shading, the performance of the PV module will also be affected. In densely populated areas such as in large cities where there are many tall buildings and do not have enough land or area to install PV arrays, shading problems cannot be avoided. This study uses modeling of partial shading and shading heaviness on one or several PV modules to determine its effect on global I-V characteristics and maximum power generated from PV arrays. Six PV modules are modeled and simulated using MATLAB in this study. The results of this study conclude that the I-V characteristic and the global maximum power output of the PV modules affected by partial shading are better arranged in series in one string then connected parallel with the inverter compared to shaded PV modules which are arranged in different string then connected parallel to an inverter. This study can be used by PV arrays designers to build a PV system in a limited area that is reliable, safe, and can still produce high maximum power under partial shading conditions.

I. Introduction

The photovoltaic system is now a significant source of energy. The photovoltaic system must have an accurate design so that it can become a reliable and safe electric power system. Interconnected photovoltaic systems have become an economical way for renewable energy-based power systems [1]. The interconnected PV modules are designed to produce voltage, current, and power that can be used with the inverter to connect to the utility grid.