Design and Control of a High-Gain Converter-Based Grid-Connected PV System for Enhanced Dynamic Performance and LVRT Capability

Conventional boost-based Grid-Connected Photovoltaic (GCPV) systems suffer from high input current ripple, voltage stress, limited gain at high duty ratios, and poor dynamic performance during Low-Voltage Ride-Through (LVRT) events. Furthermore, multi-input configurations relying on individual boost stages increase physical size and system complexity. To address these limits, this paper presents a 117 kW two-stage Dual-Input Single-Output Grid-Connected High-Gain Converter Photovoltaic (GCHGCPV) system. Standard PI loops manage the grid and battery, while an algebraic adaptive duty ratio law engages strictly during grid faults to eliminate PV integral delay. MATLAB/Simulink simulations under variable irradiance (200 to 1000 W/m²) and symmetrical grid sags, the P&O algorithm achieves a 98.6% average tracking efficiency, while the adaptive control suppresses transient peak DC-link overvoltage to 0.177% - 1.064% (reaching a maximum of 656.9 V). This maintains 193.1 V of safety headroom below the 850 V trip threshold. Moreover, grid current Total Harmonic Distortion (THD) remains strictly within IEEE standards across all conditions.