Safe-Zone Enforced Power Tracking for Hotspot Mitigation in Shaded Microinverter PV Systems

Microinverter-based photovoltaic (PV) systems face reliability risks under partial shading, where bypass diode activation causes shaded submodules (SMs) to dissipate power, creating hotspots and accelerating degradation. Conventional active power tracking (APT) methods often operate in these hotspot-prone zones, resulting in shaded-cell heating, power oscillations whenPref>PMPP, and microinverter restarts. This article proposes a safe zone operation–enforced APT algorithm that enhances the conventional method to ensure oscillation-free regulation while preventing reverse bias stress in shaded SMs. The algorithm dynamically identifies operating regions, halts perturbations underPref>PMPP, and integrates a minimum power threshold concept to avoid collapse to an open circuit during irradiance drops. Experimental validation on a microinverter prototype, supported by thermal simulations, demonstrates complete elimination of shaded SM dissipation, stable tracking across irradiance and reference variations, and continuous operation without restart. Compared to existing methods, the proposed strategy prioritizes long-term reliability while maintaining tracking accuracy, establishing a safety-driven benchmark for microinverter PV systems.