Rapid cycle testing of high current IGBT powerswitch modules

Bi-directional static converters consisting of IGBT powerswitch modules are to be fitted as a direct replacement for AC/DC link motor generators in the ASTUTE Class Nuclear Submarine. Failure mechanisms of IGBT devices under conditions of deep thermal cycling are well documented, however, the information available does not directly apply to their operation within switching converters. To demonstrate acceptable reliability and performance of the IGBT powerswitch modules in the ASTUTE main static converter, it was considered necessary to devise an application specific programme of rapid cycle testing. This programme of testing exceeds accelerated life test profiles previously reported and will be used in support of the safety justification for ASTUTE