Cryogenic power electronics at megawatt-scale using a new type of press-pack IGBT

Abstract

Electrical characteristics of a press-pack IGBT stack have been investigated experimentally in both static and dynamic tests at room temperature and at 77 K in an effort to identify a megawatt-scale class semiconductor that performs well electrically, thermally, and mechanically. It has been observed that the forward voltage drop and the turn-off time are both noticeably reduced at cryogenic temperatures, suggesting significant improvement in the device operating area. Furthermore, the stack was subjected to repeated thermal cycles between room temperature and 77 K without observing any degradation. A circuit simulation of a 200-kW boost converter based on the characterized press-back IGBT stack exhibited a reduction in switching and conduction losses at 77 K by 60% and 24%, respectively compared to the values at room temperature. It is expected that the type of press-pack IGBT stacks tested will be key elements to build high power dense, megawatt-scale cryogenic converters for future all-electric ships and electric airplanes.