A Novel Junction Temperature Estimation Approach for High Voltage IGBT Modules Based on Pre-Turn-Off Current

Abstract

Modular multilevel converter based high voltage current (MMC-HVDC) system is widely utilized in power transmission. As one of the most critical components of MMC, accurate estimation for junction temperature of high voltage IGBT is significant for its reliable operation. Some of the existing temperature sensitive electrical parameters (TSEPs) are difficult to utilized in situ considering the low sensitivity, invasive implement and dependence of bond wire degradation. To address these issues, a novel TSEP called pre-turn-off current during turn-off process which is defined as the current at a fixed delay time from the moment of 90% load current is proposed to estimate junction temperature of high voltage IGBT modules. Moreover, the pre-turn-off current model is established and validated. Experiment results show the good linearity, high temperature sensitivity and independence of bond wire degradation of this approach.