基于热时间常数的IGBT模块热疲劳老化监测方法

提出利用热时间常数作为新的特征量,实现了对IGBT模块和导热硅脂的热疲劳老化进程的同步监测。通过研究热时间常数与Cauer型热网络参数的关系,建立了热时间常数与IGBT模块物理结构间的联系,总结出热时间常数在IGBT模块热疲劳老化过程中的变化规律。最后,通过3-D有限元仿真模型和实验验证了该方法对监测IGBT模块和导热硅脂热疲劳老化的有效性。该方法的显著优势在于可以仅通过1条结温降温曲线提取热时间常数,且不需要任何损耗信息或加热模块至热平衡状态。

Thermal Fatigue Monitoring Method for IGBT Module Based on Thermal Time Constants

This paper proposes to use the thermal time constant of junction temperature cooling curve of IGBT module as an indicator for aging monitoring of IGBT modules and thermal grease. This finding is achieved by investigating the relationship between thermal time constants and thermal parameters of the Cauer thermal network, which shows that time constants increase along with the aging process of the corresponding physical structure. The salient feature is that the proposed method can be implemented without knowing the power loss information or heating the IGBT module up to steady state. Moreover, thermal time constants can be extracted using only one junction temperature cooling curve, instead of mul-tiple cooling curves with different cooling conditions. Experimental and simulation results show that the proposed method enables effective aging monitoring of the solder fatigue as well as the thermal grease fatigue.