Hot Spot Mitigation in PV Modules Using an Enhanced Zener-Based Dynamic Bypass Circuit

Hot spots in photovoltaic (PV) modules, caused by shading or mismatch, lead to localized overheating, reduced efficiency, and long-term degradation. A passive mitigation strategy using a series-connected MOSFET is commonly employed to alleviate these effects. Recent work introduced a Zener-based gate control scheme as a compact improvement over previous approaches. However, this solution lacks reliability, worsening thermal stress of components located the junction box. This work analyzes the behavior of Zener-controlled circuits compared to conventional configurations. To overcome their limitations, we propose an enhanced architecture that integrates a low-frequency oscillator to dynamically drive the series-connected MOSFET gate. Periodic switching off of the MOSFET enables timely disconnection, thereby eliminating current flow and power dissipation in both the solar cells and the MOSFET, without requiring external power or control. SPICE simulations, including DC sweep and transient analyses, validate the performance of both traditional and improved circuits. Results confirm the effectiveness of the proposed design in mitigating hot spots while preserving the simplicity and low cost of passive solutions.