IGBT Junction Temperature Measurements: Inclusive of Dynamic Thermal Parameters

Insulated gate bipolar transistors (IGBTs) are widely used in new energy fields, such as wind power converters and electric vehicles. The junction temperature characteristics and junction temperature measurements greatly influence the reliability of the IGBT. During switching, the electrical parameters of the IGBT undergo considerable change. The thermo sensitive electrical parameter (TSEP) method has been commonly used to extract junction temperature. The TSEP method has the inherent advantages of being able to take measurements quickly and accurately, in a non-intrusive manner. The junction temperature estimate under the on-state condition cannot reflect the reliability of the IGBT during the dynamic switching process. The solution to this dilemma is to measure the junction temperature using the dynamic TSEP method during the IGBT turn-off process. The junction temperature is measured by the reverse voltage peak between the auxiliary emitter and power emitter, which forms during the IGBT turn-off process. The feasibility of the proposed method has been experimentally verified.