一种考虑热扩散和热耦合的IGBT模块热阻抗模型

Thermal impedance model for IGBT modules considering heat spreading and thermal coupling

针对传统热等效电路模型对IGBT模块结温计算误差较大的问题,提出一种基于传热研究的IGBT模块等效热阻抗模型。通过对IGBT模块内部传热研究,以热流密度变化规律确定热扩散角,由此计算出热网络参数并建立改进的单芯片Cauer网络等效电路模型。然后在此基础上,考虑多芯片之间的热耦合效应,计算出自热热阻和耦合热阻并建立IGBT模块热阻抗矩阵,利用线性叠加原理可对各芯片的结温进行预测计算。最后,将等效热阻抗模型计算出的结温与有限元仿真值进行比较,验证了该模型的有效性与准确性。

Aiming at the problem that the traditional thermal equivalent circuit model has large error in calculating the junction temperature of IGBT module,an equivalent thermal impedance model of IGBT module based on heat transfer research is proposed. By studying the heat transfer inside IGBT module,the heat spreading angle is determined according to the law of heat flux variation. Thermal network parameters are calculated and an improved equivalent circuit model of single chip Cauer network is established. Then,considering the thermal coupling effect between multi-chips,the self-heating thermal impedance and coupling thermal impedance are calculated and the thermal impedance matrix of IGBT module is established. The junction temperature of each chip can be predicted by using the linear superposition principle. Finally,the junction temperature calculated by the equivalent thermal impedance model is compared with the finite element simulation value,which verifies the effectiveness and accuracy of the model.