Reliability Analysis of Three-Phase Transformer-Less UPS Using SiC Devices

Due to the recent development and production of semiconductor switching devices with a Wide Band Gap, research aimed at reducing power conversion losses and improving efficiency has been actively conducted. Studies are also ongoing to apply SiC MOSFET in Uninterruptible Power Supply (UPS) systems that protect critical load equipment from power distortions and outages, with the goal of achieving high efficiency and high power density. However, research on the reliability of UPS systems, particularly in predicting their operational lifespan and improving availability through preventive maintenance, remains relatively insufficient. In this paper aims to design a Transformer-less UPS based on SiC MOSFET and compare and analyze its reliability with that of conventional Si IGBT-based UPS systems.