Investigating effects of shading on performance of solar conversion devices

The amount of electrical energy generation from solar photovoltaic (SPV) module depends on the range of incoming solar radiation. Generated current (as well as output power) is proportional to the amount of solar irradiance received by module. SPV module typically consists of 36 or 72 solar cells of specific area interconnected in series or parallel network to achieve required power output and in order to generate rated power, all cells should be exposed to same irradiance. In this paper, partial shading assessment on 40 W module connected in distributed network is carried out. Individual module is connected with solar parameter data logger to measure accurate instantaneous data. The data logger is based on INC MPPT method. Cell level modeling is carried out to understand the effect on module output power when individual solar cells are exposed to different irradiance levels. Experimental results show that short circuit current reduces by nearly 60% when even single solar cell in module gets partially shaded.