Analysis of the Effects of Partial Shading on Cell Performance in a Half-Cut Cell Photovoltaic Module

Half-cut cell photovoltaic (PV) modules have become increasingly popular in today’s solar market, offering improved efficiency and reduced power losses compared to standard full-cell modules. These modules aim to reduce electrical losses and improve performance under real-world conditions. The unique structure and configuration of these modules introduce complexities when operating under real-world conditions, especially under partial shading conditions. This study investigates the effects of partial shading on the electrical and thermal characteristics of individual cells in a half-cut cell PV module. Measurements of individual cell voltages, substring currents, and module currents were taken under various shading conditions using a custom-made set-up. Partial shading caused a current mismatch and reduced the voltage across the shaded cell causing an increase in the operational voltages and temperatures of the unshaded cells connected in series with the shaded cell, and a decrease in the voltage of the shaded cell. Fully shading a single cell causes the parallel unshaded substring pair to operate at the same voltage under near short-circuit conditions, resulting in reverse biasing of some cells in the unshaded substring. The results also show that the thermal characteristics of the unshaded cells in the parallel substring may be affected by the partially shaded cell. These findings aid in understanding the effects that partial shading has on the electrical and thermal characteristics of half-cut cell modules and in the interpretation of their thermal images. It was noted that, if substrings were optimized to operate at their individual MPPs, a shaded cell would not become reverse-biased, even with significant shading. It is important to note that module-level optimization doesn't always translate to optimal substring operation.