A comparative analysis of single-phase single-source multilevel inverter topologies for PV applications

Abstract

• Analysis of classical multilevel inverter topologies (NPC & FC). • Analysis of ameliorated reduced switches topologies (PUC & S-PUC). • Choice among all of them based on THD rate. • Applying the chosen topology in two stage PV system grid connected. • Results comparaison with other architectures Multilevel inverters have become indispensable in modern power electronics, thanks to their ability to improve energy conversion efficiency and power quality. However, their operation from a single DC power source presents a major challenge: maintaining voltage balance across DC bus capacitors. Conventional solutions to this problem often rely on complex control architectures, including additional sensors and sophisticated modulation schemes, which increases cost, size, and computational load of the system. This article addresses the critical issue of capacitor voltage balance in multilevel inverters powered by a single DC power source. While efficient, current solutions often suffer from an excessive reliance on sensors and complex control algorithms that increase the computational load. This article presents a comparative study of four inverter architectures, classified into conventional and advanced topologies. The analysis focuses on the hardware structure, the number of components, the modulation techniques, and the spectral quality of the output signals. The objective is to identify the most efficient topology for optimal integration into a photovoltaic system. Validated simulation results reveal that advanced topologies maintain voltage balance, sometimes without the need for additional sensors, while guaranteeing exceptional spectral performance with a THD as low as 0.37% in a grid-connected system. This excellent wave quality confirms the suitability of these solutions for grid-connected applications, offering an ideal compromise between control robustness and conversion efficiency. This work thus provides a technical selection framework for the development of future generations of inverters in single-source DC systems.