Optimal Conversion Topologies for Grid-Connected PV Systems: A Comparative Study of Single-Stage and Two-Stage Configurations

Abstract

With the ongoing rise in global energy demand, grid-connected photovoltaic (PV) systems are increasingly recognised as a viable and sustainable energy alternative. These systems primarily operate using one of two distinct topologies: the two-stage (DC-DC-AC) configuration, in which the voltage from solar panels is initially boosted by a DC-DC converter before being converted to AC through an inverter. While functional, this design presents inherent drawbacks, including increased system size, higher costs, and reduced efficiency due to multiple conversion stages. To address these challenges, the single-stage (DC-AC) topology has been developed, directly linking solar panels to the inverter and eliminating the need for a DC-DC converter to enhance overall system efficiency. This study aims to identify the optimal topology for grid-connected PV systems by offering a comprehensive comparative analysis of power loss, system efficiency, and MPPT algorithm performance across these two configurations in a 150 kW grid-connected PV system under varying irradiance conditions. The simulation results underscore the superiority of the single-stage topology, demonstrating its streamlined design, cost-efficiency, and improved energy performance. Consequently, this analysis provides a valuable framework for engineers and researchers in selecting optimised configurations for grid-connected PV systems