Strategy for Diagnosing the Aging of an IGBT Module by ON-State Voltage Separation

An insulated-gate bipolar transistor (IGBT) module has two aging modes: 1) bond wire fatigue and 2) solder fatigue, both of which have a significant impact on the reliability of power electronic systems. A good way to increase the service life of such systems is to apply different compensation strategies according to different aging modes. As one of the simplest parameters in online measurements, the ON-state voltage is influenced by both types of fatigue, but its changes are not due solely to the aging of the IGBT module. Considering how the collector current and junction temperature influence the ON-state voltage, this article separates the ON-state voltage into three parts for the purpose of diagnosing IGBT module fatigue. In this article, the package voltage was extracted, which reflects the bond wire fatigue influence on the ON-state voltage of the IGBT module directly. This supplements the existing diagnostic method and realizes fatigue diagnosis under different working conditions.