Power Cycling and Research on Failure Mechanism of Press-Pack IGBT based on Thermal Resistance Composition Testing

Press-pack insulated gate bipolar transistor (IGBT) is widely used in transmission systems due to its high reliability and short-circuit failure modes. However, there is a lack of research on the failure mechanism of elastic press-pack IGBT. For the elastic press-pack IGBT sub-module, based on the principle of electrical measurement, this paper designs a power cycling test system for power cycling test and thermal resistance measurement. Based on the structure function method, the changes of electrical properties and thermal resistance after power cycling are studied. The reliability and failure mechanism of the elastic crimp IGBT sub-module are analyzed, and the conclusion that the gate oxide layer damage is the main failure principle is obtained. The work of this paper fills the gap in the practical application of elastic press-pack IGBT.