Trap Characteristics and Their Temperature-dependence of Silicone Gel for Encapsulation in IGBT Power Modules  

作　　者：Jiayu Xu Xuebao Li Xiang Cui Zhibin Zhao Shenyang Mo Bing Ji 

机构地区：[1]State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China [2]School of Engineering,University of Leicester,Leicester LE17RH,UK

出　　处：《CSEE Journal of Power and Energy Systems》2021年第3期614-621,共8页中国电机工程学会电力与能源系统学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China-the State Grid Corporation Joint Fund for Smart Grid(U1766219);the Fundamental Research Funds for the Central Universities(2019QN120).

摘　　要：Silicone gel is a prevailing material for encapsulation in insulated gate bipolar transistor(IGBT)power modules.The space charge transport behavior in silicone gel is significant to evaluate the electrical insulation characteristics.This paper focuses on the trap characteristics and electrical properties of the silicone gel,which were rarely studied before.The experiments are performed on the surface potential decay of silicone gel after the charge injection.Then,the energy distributions of electron or hole traps are determined by a double-trap energy level model,which can be fitted by the Gaussian distribution.In addition,the mobilities of positive and negative charges are determined,which are 1.38×10^(-12) m^(2)·V^(-1)·s^(-1) and 1.74×10^(12) m^(2)·V^(-1)·s^(-1),respectively.Furthermore,considering the heat as a byproduct resulting in thermal issues,the temperature-dependence of surface potential decay characteristics are also studied in this paper.When temperature rises,the decay rate of surface potential increases,especially when the temperature is higher than 80℃.Finally,the contrastive analysis illustrates that the trap characteristics of silicone gel are between the trap characteristics in liquid-state material and solid-state material,which supports the phenomenon that silicone gel is more resistive to the sharp edges in power modules.This work can provide a useful reference for the design of encapsulation in high-voltage IGBT power modules.

关 键 词：Charge mobility IGBT power modules silicone gel TEMPERATURE-DEPENDENCE trap characteristic 

分 类 号：TQ127.2[化学工程—无机化工]