The Research On Degradation Test Of On-state Electrothermal Characteristics For IGBT Module

Insulated gate bipolar transistor(IGBT),as a kind of power semiconductor devices,have been widely used in electric locomotive traction,wind power generation,aerospace and other key areas.These areas have higher requirements for IGBT module whose reliability and safe operation affect the stability of the entire equipmemt or system.IGBT module is in the cycle of the thermal stress which produced the huge fluctuations of junction temperature,and which will affect the degradation of on-state electrothermal characteristics for IGBT module.The performance degradation data of on-state electrothermal characteristics contains a lot of information related to reliability and safe operation.Hence,testing characteristic parameter and researching on reliability assessment,life prediction as well as degradation regularity of IGBT module are of great significance both on theoretical and practical value.This subject analyze the changing characteristics of the main on-state electrothermal characteristics of IGBT module considering saturation conduction as temperature parameters.Firstly,analyze the basic structure and the on-state characteristics of IGBT module deeply.Analyze the impact of junction temperature for IGBT module volt-ampere characteristic from the viewpoint of semiconductor physics,pointing out that IGBT module has different volt ampere characteristics under different collector current.Study the IGBT module failure associated with encapsulation and chip.Afterwards,study on-state electrothermal characteristics of IGBT module test and degradation test method.In order to monitor the changing characteristics of the main on-state electrothermal characteristics of IGBT module,design and build accelerated degradation testing system and the on-state electrothermal characteristics testing system.Accelerate the degradation process through the accelerated degradation testing system and obtain the IGBT module trend of degradation of on-state electrothermal characteristics through the on-state electrothermal characteristics test experiment before and after degradation of the IGBT module.The test results provide the mathematical basis for further research of IGBT module's on-state electrothermal characteristics.Finally,analyze the degradation regularity combined with theoretical research and the trend of the data.Establish mathematical model with higher preliminary of Saturationvoltage and drop collector current and junction temperature and this model still applied before and after degradation of the IGBT module.Analyze the shell temperature rising process under electric heating condition and establish mathematical model of the shell temperature rising process before and after degradation of the IGBT module with higher preliminary.Acquire the dynamic curve of the the junciton temperature rising process according to the mathematical model of Saturation voltage and drop collector current and junction temperature andlay a foundation of on-line monitoring and reliability study of IGBT module's junction temperature.