Research on Remaining Lifetime Evaluation for Traction System IGBT Devices of Electric Locomotives with Different Service Mileage

In electric locomotive system, the function of traction converter depends heavily on IGBT module, and IGBT module is prone to failure. Traditionally, ensuring safety has involved expensive and wasteful “mileage maintenance', which includes regular replacement of IGBT modules. Therefore, assessing the residual reliability of these modules, taking into account their different service miles, is meaningful. Firstly, the dynamic and static characteristics of IGBT modules under different service mileage are compared and analyzed. Secondly, the power cycling test for different mileage IGBT modules is carried out to analyze the differences between them. Then the microscopic analysis of the failure module further confirms the results of the failure analysis. Finally, the fatigue accumulation state of IGBT modules can be deduced from the power cycling test data to predict the remaining life of IGBT modules. This study reveals that the health state is unevaluable using dynamic or static characteristic parameters. It is proved that the power cycling tested results are significantly different for different service-mileage devices. Finally, a remaining lifetime predicted method of power devices is proposed, where the health status is inverted by the power cycling tests.