Performance analysis of a solar array under shadow condition
The investigation deals with performance studies of a solar array consisting of two modules, each having 25 cells in series. The load characteristics of the array are studied experimentally and it is observed that, as the shadowed area increases, the overall performance of the array is significantly degraded. Theoretical analysis of such an array has also been carried out to explore the possible mechanisms responsible for array degradation. In the analysis, we consider an additional series resistance for the dark region, whereas earlier workers have overestimated the contribution of the dark region because they have always taken into account identical series resistances for the illuminated, as well as the dark, region. Simulation of the enhanced series resistance of the dark region in the present work has been done by the effective surface resistance of the emitter layer caused by a metallic grid, because of the biasing of the dark region by the illuminated area. Under such biasing, the dark region acts as a load on the illuminated region and causes a loss of current. This is simulated by an additional series resistance (Rsurf). The analysis, which is based on consideration of the enhanced series resistance of the dark region, produces a better match between experimental and theoretical results.