13 kV SiC-DMOSFETs and body diodes for HVDC MMC converters

Abstract

Abstract Power electronics utilizing SiC power devices will become key components in next-generation power systems based on renewable energy, which are becoming an urgent issue worldwide. In this study, the on-characteristics and switching characteristics of 13 kV SiC-double-implanted metal-oxide-semiconductor field-effect transistors (DMOSFETs) and their body diodes were measured. In particular, the carrier lifetime, which has a significant effect on electrical characteristics, was estimated from the dynamic characteristics of the body diodes. The short carrier lifetime resulted in a large on-state voltage and a small reverse recovery loss of the body diode. Moreover, a conceptual design of a modular multilevel converter-based high-voltage, large-capacity, and self-excited AC/DC converter with 13 kV SiC-DMOSFETs was conducted, and its characteristics were investigated. When the 13 kV SiC-DMOSFETs were applied, the ratio of the total device loss to the electricity power of the converter was 1.10%, which is a significant reduction of 50% compared with 2.17% when 6.5 kV Si-insulated gate bipolar transistors were used.