## 6 Conclusions  
An improved power optimizer architecture for photovoltaic (PV) string have been introduced to address partial shading, where a buck converter has been used for each module. The buck converter, typically underutilized, is shown to be well-suited for handling partial shading effects by converting the lower current from shaded modules into higher output current. The unique design philosophy, layout formation under different conditions, control mechanism, and fundamental operation of the proposed architecture have been comprehensively explained. In connection, it is proved that the proposed architecture activates only the converters for the shaded modules, without drawing additional current from the inverter's DC-link. Because of this, the proposed architecture contains the advantages of both complex and basic architectures, i.e., offering high efficiency, low voltage stress, selective operation of basic topology, and reduced control complexity, while avoiding their respective drawbacks. The design philosophy and operation of the proposed architecture have been validated through simulations, demonstrating an efficiency exceeding 97% under normal conditions. A comparative analysis of different architectures highlights the superior performance and better features of the proposed architecture.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Shading Cases** & **Conventional** & **Advanced [21]** & **Proposed** \\ \hline Active Converters: \(\leq\)30\% & 90–92\% & \(\geq\) 96\% & \(\geq\) 97\% \\ \hline Active Converters: Between 30\% & & & \\ and 75\% & & & \\ \hline Active Converters: \(\geq\) 75\% & 90–92\% & 87–89\% & 90–91\% \\ \hline \end{tabular}
\end{table}
Table 1: Average efficiencies of architectures with different levels of active converters under partial shading.  
Figure 11: Five parameter-based feature analysis of three architectures: (**a**) conventional, (**b**) advanced [21], and (**c**) proposed.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Features** & **Conventional** & **Advanced [21]** & **Proposed** \\ \hline Efficiency & Medium & High & High \\ \hline Selective Converter Operation & Unavailable & Selective & Selective \\ \hline Converter Topology & \
\begin{tabular}{c} Non-isolated Basic \\ (Buck-Boost) \\ \end{tabular} & Isolated Complex & Non-isolated Basic (Buck) \\ \hline Control Operation Complexity & Low-Medium & Complex & Low-Medium \\ \hline Switching Devices Connection and Voltage Stress & Differential and Low &
\begin{tabular}{c} Non-differential and \\ High \\ \end{tabular} & Differential and Low \\ \hline Inverter’s DC-link Involvement for Mismatch Current & Not needed & Needed & Not needed \\ \hline \end{tabular}
\end{table}
Table 2: Comparative analysis of parameters and features of three architectures.  
**Author Contributions:** Conceptualization, A.F.M.; methodology, A.F.M., A.A. and F.S.; software, A.F.M. and A.A.; validation, A.F.M.; formal analysis, A.F.M., A.A. and F.S.; investigation, A.F.M., A.A. and F.S.; resources, A.A. and F.S.; writing--original draft preparation, A.F.M. and A.A.; writing--review and editing, F.S.; visualization, A.F.M., A.A., and F.S. All authors have read and agreed to the published version of the manuscript.  
**Funding:** There is no funding associated with the research work of this paper.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data are not available on a publicly accessible repository and they cannot be shared under request.  
**Acknowledgments:** The Researchers would like to thank the Deanship of Graduate Studies and Scientific Research at Qassim University for financial support (QU-APC-2025).  
**Conflicts of Interest:** The authors declare that there are no conflicts of interest amongst the authors regarding the publication of this article.