A Hybrid Model of Turn-Off Loss and Turn-Off Time for Junction Temperature Extraction

Temperature-sensitive electrical parameter (TSEP) approaches are widely employed in the junction temperature (Tj) extraction and prediction of power semiconductor devices. In this paper, the turn-off loss (Eoff) and turn-off time (toff) are presented as temperature-sensitive electrical parameters. The abrupt change in the junction temperature of Insulated Gate Bipolar Transistor (IGBT) occurs during switching is proved. Common deficiencies in a single temperature-sensitive electrical parameter were considered, including the necessity of the collector currents exaction, the poor junction detection accuracy. Therefore, after the linear relationship between junction temperature and turn-off time, and turn-off loss is proved, a hybrid model based on turn-off loss (Eoff) and turn-off time (toff) is proposed to extract junction temperature accurately. The experimental results show that the proposed method is with the advantages of high accuracy and strong anti-interference ability. Although some high-precision probes are required for parameter extraction, it indicates the internal mechanism of junction temperature mutation of the power device, and it is of great value for the reliability of the power devices that operate continuously.