IGBT模块与散热器接触界面气隙对散热的影响研究

Research on Effect of Air Gap between IGBT Module and Heatsink on Thermal Performance

IGBT模块与散热器接触界面使用导热硅脂来降低接触热阻,在轨道交通领域,由于运行环境的频繁振动和温度循环,使硅脂可能发生挥发、流失或干涸,从而在接触界面产生气隙,使传热条件恶化。文章通过数值仿真以及热性能试验2种方法,研究界面气隙对IGBT模块结温和壳温的影响。结果表明,在硅脂气隙产生的初期,气隙对IGBT结温的影响较小;随着气隙扩大,则会使结温明显升高,导致IGBT模块寿命降低,甚至使IGBT模块迅速损坏。

Thermal grease is used to reduce the contact resistance of the contact interface between the IGBT module and the heatsink in the field of rail transit.Because of the frequent vibration and the cyclic temperature fluctuation of the IGBT module,the thermal grease could volatilize,flow out,and even dry up,which could cause an air gap between the module and the heatsink,heat transfer conditions was worsen.The effect of the air gap on the temperature of the IGBT junction and the shell has been studied based on numerical simulation and experiment.The results showed that the air gap has less influence on the junction temperature in the intial stage,with the expansion of the air gap,the junction temperature increase obviously and lead to the declining of the life of the IGBT module,and even IGBT module rapidly damage.