Comparison of 13.8kV Grid-tied Converters Cost and Efficiency

Abstract

This work presents a study of converters for interfacing 13.8 kV feeders in a microgrid, aiming for high efficiency and lower costs. An analysis of classical two and three-level topologies is carried out, evaluating low- and medium-voltage converter solutions. To assess efficiency, the thermal module of the PSIM Simulation software was used, while inductor and capacitor losses were calculated based on the presented equations. For converter selection, an optimal design analysis was performed to determine the best cost-benefit topology combination and explore potential cost reductions. It is shown that the NPC/NPC topology combination with medium-voltage IGBTs is the best choice, as it provides high efficiency in all simulated scenarios while remaining cost-effective.