压接IGBT小管壳与外框高温热老化绝缘特性

High Temperature and Thermal Aging Insulation Characteristics of Small Shell and Outer Frame for Press-pack IGBT

近年来IGBT模块朝着更高电压等级与更大功率密度的方向发展,有限空间内的高电压与大电流将使得器件在高温下的绝缘失效概率急剧增加,模块中承受长时间高温的封装材料面临着绝缘退化乃至失效的风险。因此,亟需针对IGBT模块中封装材料开展高温与热老化绝缘特性研究。文中面向压接IGBT中的小管壳玻璃纤维增强型聚对苯二甲酰癸二胺和外框玻璃纤维增强不饱和聚酯封装材料,通过微观形貌、组分、介电及沿面闪络描述了两种材料的高温与热老化特性。结果表明,两种材料在热氧老化后出现不可逆的黄变现象,组分显示这与有色官能团的增加有关。此外,两种材料介电与电导性能在高温与热老化后都有所退化,尽管如此,外框仍旧满足IEC标准中关于介质损耗因数的要求(≤0.03)。小管壳和外框在150℃高温下耐压分别下降27%与29%,能带结构的计算结果验证了沿面闪络的退化行为。

In recent years,IGBT have developed towards higher voltage and power densities.High voltages and high currents in limited space will sharply increase the probability of insulation failure at high temperatures.The encapsulation material exposed to high temperatures for a long time is facing the risk of insulation degradation and even failure.There-fore,it is urgent to conduct research on high temperature and thermal aging insulation properties in IGBT modules.This paper describes the high temperature and thermal aging characteristics of the small shell PA10T and outer frame UPM203 of the press-pack IGBT through the microscopic morphology,composition,dielectric constant,electrical conductivity,and surface flashover.The results show that the two materials irreversibly become yellow after thermo-oxidative aging,and functional group tests reveal that this phenomenon is related to an increase in colored functional groups.The dielectric and electrical conductivity are degraded after high temperatures and thermal aging.However,Outer frame still meets the requirements of the IEC standard(≤0.03).The flashover voltage of small shell and outer frame will drop by 27%and 29%,respectively,at a high temperature of 150℃.And the simulation results of band structure confirms the degradation be-havior of surface flashover.