Research on On-line Reliability State Detection Method of Power Electronic Devices Based on Turn-off Losses

Insulated gate bipolar transistor (IGBT) has been widely used in photovoltaic power generation, aerospace, electric vehicles, ships and many other fields. As the core component of the equipment in these fields, the reliability of IGBT has always been an important research direction of power electronics. The existing research results show that the reliability of IGBT is closely related to its junction temperature change. How to estimate or measure the junction temperature of IGBT is the key point of its reliability research. Based on the need of reliability research, this paper proposes a junction temperature extraction method based on the turn-off losses, which uses the single loss Eoff in the process of IGBT turn off as the thermal sensitive parameter. In this paper, a non-contact state detection method is proposed, which uses the input and output voltage and current information of single inverter to predict the junction temperature without directly measuring the IGBT. This paper has certain theoretical significance and engineering value for the follow-up IGBT online reliability state detection.