Analysis of Partial Shading Effect on the Crystalline Silicon Photovoltaic Module Temperature Distribution

The electrical mismatch occurs in the serially connected solar cells under the partially shaded photovoltaic (PV) modules due to non-uniform illumination. The mismatch leads to a non-uniform distribution of temperature in the PV module, which can have a detrimental effect on long-term reliability and instantaneous output power. The present research aims to study temperature distribution under the active and inactive states of bypass diode in a partially shaded PV module. The distribution of temperature in a shaded PV module is estimated using the proposed electro-thermal PSPICE model. The temperature distribution has been estimated and analyzed for an increasing number of shaded cells and their shaded area. The proposed model is validated with the experiment. Results show that the temperature gradient and its distribution in a shaded PV module changes in the transition of bypass diode state from inactive to active. This change in temperature gradient and its distribution has been quantified in terms of the thermal shade effect factor. A thermal shade effect factor value less than −1 indicates the temperature gradient amplification during the active bypass diode state. This amplification would cause the temperature of the shaded cell to rise manifold. On the other hand, a thermal shade effect factor value greater than −1 indicates the higher temperature gradient during the inactive bypass diode state.