Performance of Smart PV Modules Under Non-Uniform Solar Irradiance

The objective of this paper is to study and help understanding the performance of smart PV modules when exposed to non-uniform illumination. A PV string composed of five smart modules connected in series are employed to conduct the study. Each smart module is composed of a single PV incorporated with its own perturb and observe MPPT and a power conditioner as distributed dc power optimizer. The performance of PV string of smart modules is compared with that of conventional single MPPT system at the same operating conditions. According to the obtained results, the string of smart PV modules has superior performance in terms of: elimination of local maximum power points that exist in conventional PV system (due to partial shading) and extracting higher power from the entire PV string with nil domino effect. Under non-uniform illumination, the power produced from the PV string of smart modules is 76 % higher than that produced from the conventional configuration, and is 59 % higher than the conventional configuration operating with Global Maximum Power Point (GMPP) tracking system. The results indicate that the performance degradation in any non-uniformly illuminated module is kept localized and does not deteriorate the performance of other modules. While in the conventional PV system, the poorest performing module drags down the performance of the entire array resulting in sever lower power capability.