A Novel Condition Monitoring Method for Full Modes of Package Degradation in High Power Modules Based on Hysteresis Curves of Forward Voltage Drop

Package degradation for high power IGBT Modules would seriously affect the operation safety of power electronic converters. Due to the variety of degradation modes, state-ofthe-art monitoring methods still struggle to comprehensively evaluate the health status of the module. Therefore, this paper aims to propose a novel condition monitoring method for full modes of package degradation in high power IGBT modules. The hysteresis curve of forward voltage drop was found for the first time to contain the critical information to separate the different degradation mechanisms. The corresponding monitoring circuit and diagnostic process were also proposed and further carried on an inverter prototype with 150A peak current. The experiment results show that the different degradation modes, i.e., bond wires lift off, solder fatigue and thermal grease aging for IGBT modules can be effectively identified by the hysteresis curve. This method is expected to reduce the difficulty of converter maintenance in field application, as it is possible to accurately distinguish whether the degradation is internal or external to the IGBT module.