An analytical approach to study partial shading effects on PV array supported by literature

This paper presents the effects of partial shading on PV arrays. The characteristics of PV array under various shading patterns are modeled in the form of current-voltage graphs. The analysis of these graphs leads to several critical observations, which are summarized in five statements. Based on these statements, two hypotheses are presented: 1) irrespective of any partial shading pattern, maximum number of local maxima in a PV array is equal to the number of series connected modules in a string, 2) number of local maxima in a PV array is equal to the quantity of open circuit voltage values (excluding last value) around which bypass diodes of the shaded modules become forward biased plus 1. Finally, both hypotheses are verified with the help of simulation results. Other than that, our findings provide exact information about the shaded PV module in an entire PV system. This study strengthens not only the theoretical knowledge of shading phenomena but also helps exploring the partial shading effects on PV array without any aid of software, advanced techniques or practical systems.