Overview of monitoring methods of press-pack insulated gate bipolar transistor modules under different package failure modes

Press-pack insulated gate bipolar transistor modules (PP-IGBTs) have been widely used in high-voltage and high-power-density applications, such as high-voltage direct-current (HVDC) converters, because of their advantages of low thermal resistance, double side cooling, and short-circuit failure mode. Package failure is one of the main reasons for IGBT module failure. Package condition monitoring is the key to realizing modules fault diagnosis, condition prediction, and intelligent operation and maintenance. At present, a variety of characteristic parameters, such as on voltage and junction temperature, are used in package condition monitoring. However, the characteristic parameters show different variation laws under different package degradation modes. Therefore, the relationship between package degradation modes and characteristic parameters is the key to realizing the condition monitoring, so as to improve the reliability of the power electronic system. In this paper, first, the package structure of a PP-IGBT is analyzed. Second, the mechanisms of fretting wear degradation, gate-oxide degradation, spring degradation, lid warping degradation, micro arcing degradation, short-circuit failure, and open-circuit failure are reviewed. The variation laws of characteristic parameters under each degradation and failure mode are then investigated. Finally, three difficult problems including characteristic parameter measurement, especially pressure monitoring, high-sensitivity detection, and characterization and evaluation, are discussed and analyzed.