An Improved IGBT Life Prediction Method

With the rapid development of power electronics technology,IGBT has been widely used in new energy,locomotive traction and other fields.Because IGBT runs for a long time,the fatigue stress will lead to the aging of its material structure.Therefore,the research on IGBT life prediction method to improve the reliability of power electronic equipment,reduce the failure rate and operation cost has become a hot topic in recent years.This paper presents an improved life prediction method from the point of view of device aging.Centered on this topic,this paper carried out research from the following aspects:(1)The transient thermal impedance curves of IGBT under different aging degrees were obtained by using the existing transient thermal impedance measurement technology of power devices,and the thermal network model was fitted with the curves.The accuracy of the model parameters was verified by comparing with the device manual.Based on this model,the aging rule of thermal resistance and heat capacity is analyzed.(2)Power loss of IGBT model is established and the thermal network model,based on the power loss model and different aging degree of thermal network model,set up different aging degree of electro-thermal coupling model,to provide data for life prediction method,and through the junction temperature data obtained by simulation with Plecs software contrast,electric heating model calculation is verified the accuracy of the junction temperature.(3)The damage accumulation rule and junction temperature statistical method of power device life prediction are analyzed,and an improved life prediction method is proposed,that is,the real-time feedback of damage accumulation degree is used to modify the electrothermal model in the process of life prediction,and the life prediction is carried out by using the junction temperature simulated by the modified model.(4)Perform power cycling experiments on IGBTs and obtain failure parameters,establish life models and improve them.Through the life prediction of the IGBT in operation,it is verified that the predicted result of the improved life prediction method?(8₁ is 0.019,and the calculation error?(8₂ of the general method is 0.098.The improved life prediction result has a smaller error and higher accuracy.The research results of this paper have certain reference value for IGBT lifetime prediction.