Press-pack IGBTs are extensively utilized in flexible HVDC systems.Because the thermal expansion effect between different materials of the device will significantly affect the mechanical stress in the power cycle and actual op-eration,it is difficult to obtain the mechanical stress by the experiments,resulting in difficult and inaccurate prediction for fatigue life.Therefore,it is necessary to study a high-precision simulation model consistent with the reality to calculate the internal stress parameters of the device so as to address issues such as life prediction difficulties and inaccurate fore-casts.Firstly,the physical characteristics that affect the accuracy of the FEM of IGBT are analyzed,and a high-precision electrical-thermal-mechanical multiphysics IGBT model is proposed,in which the dynamic conductivity of IGBT chips is taken into consideration.Secondly,the accuracy of the model is verified by experimental comparison and analyses of the saturation voltage drop,junction temperature,and Von Mises stress.Finally,the stress variation characteristics of the IG-BTs during the power cycling are analyzed by using the Multiphysics model proposed in this paper.The concept of"extra stress difference"is proposed to characterize the special change law of the stress of IGBT in the power cycle and to ana-lyze the generation mechanism of extra stress difference.The significance of stress characteristics in the study of life prediction is expounded.
关键词
压接型IGBT/动态应力特性/额外应力差/应力寿命预测/有限元仿真/电-热-力多物理场耦合
Key words
press-pack IGBTs/dynamic stress characteristic/extra stress difference/stress life prediction/FEM simu-lation/electrical-thermal-mechanical multiphysics model
维普
万方数据