Topology selection and power optimization of photovoltaic arrays with hybrid cross-tie retrofit under partial shading

Partial shading leads to uneven irradiance distribution within photovoltaic arrays and induces branch‑current mismatch and multi‑peaked power-voltage curves, thereby degrading the efficiency of distributed photovoltaic systems. Most static and dynamic reconfiguration schemes take the total‑cross‑tied topology as the optimization basis yet overlook wiring complexity and retrofitting costs, making them unsuitable for cost‑constrained small‑scale photovoltaic scenarios. This work systematically compares five conventional topologies and five hybrid topologies under ten typical partial‑shading conditions. A multi‑dimensional evaluation framework is built using metrics including global maximum power point, shading loss, mismatch loss, fill factor, conversion efficiency, performance ratio and the number of cross‑tie connections. Scenario‑specific topology‑selection criteria are summarized for permanent building shading, and average performance across all partial‑shading conditions quantifies each topology’s adaptability to stochastic temporary shading. Simulations on a 6 × 6 photovoltaic array show that the proposed hybrid topologies achieve 1.25–4.34% power gains versus conventional schemes with a good trade‑off between power output and wiring complexity. A localized cross‑tie retrofit strategy is further proposed, yielding 2.26–5.25% power gain without rearranging the original photovoltaic module arrangement. All conclusions are derived from numerical simulations and offer theoretical references for small‑scale photovoltaic array planning and retrofitting.