Electrical Characteristics of a Solar Cell/PV Module

Abstract

Conventionally, a PV system consists of solar PV arrays and electric converters. A PV array is formed by series/parallel combination of solar modules. Some operating conditions result in non-uniform irradiance of PV array, such as shadows, clouds, dirt, debris, bird droppings, different orientations and tilts, and so on. If several solar cells in a series PV module are mismatched due to non-uniform irradiance, these cells will limit the output current of normal cells. This leads to decrease of the output power, even generates hot-spot and causes damage to these cells. To avoid the destructive effects of hot- spot, a bypass diode is connected in parallel with a PV module or parallel with some series-connected solar cells in a PV module, which creates a replacement path. To model solar cell, the one-diode model has been proposed, and some researchers have studied how to extract parameters for the model. For a higher accuracy, two- diode model has been studied for years. In this research work, some methods were developed to determine the electrical parameters in these models. The electrical characteristics of a solar cell/PV module derived from those proposed models match the experimental data well when irradiance is uniform.