Improving Power Quality in Double-Stage Single-Phase Grid-Conneted PV Inverter System using MPPT-FLC-PSO and FLCs

This paper presents a double-stage control for a single-phase grid-tied photovoltaic (PV) converter-inverter system using fuzzy logic controllers (FLCs). The converter stage utilizes a maximum power point tracking (MPPT)-based FLC with a voltage-based search space reduction strategy is used to enhance tracking control response. Two additional FLCs are incorporated in the inverter stage to simultaneously regulate the DC-linked voltage for power flow balancing and control the grid current for improved power quality. Through particle swarm optimization (PSO), the topology and fuzzy parameters of the FLCs are optimized, thereby eliminating conventional design, and reducing computational complexity. The proposed PSOFLCs are implemented and evaluated on a 2.5 kW PV system. Simulation results demonstrate the effectiveness of the proposed FLCs in increasing energy utilization efficiency and inverter efficiency up to 10% compared to classical and conventional controllers, including reduce total harmonic distortions of grid-current and achieve near-unity power factor.