Influence mechanism of solder aging and thermal network model optimization of multi-chip IGBT modules

Abstract

With the continuous increase in the scale of new energy grid-connected, high-power converter IGBT modules are widely used in wind, solar, and other new energy power generation systems. The safe and reliable operation of IGBT modules with parallel chips is becoming more and more important. In the multi-chip module, uneven solder aging will increase the thermal resistance of some chips, which will lead to an inaccurate estimation of the junction temperature of the multi-chip IGBT power module. To this end, this paper proposes to use the reconstructed thermal impedance matrix to modify the multi-chip thermal network model and estimate the junction temperature. By analyzing the nonlinear accelerated deterioration law between the aging degree of the solder layer and the self-thermal impedance and coupled thermal impedance of the IGBT module, the influence mechanism of different solder layer aging degrees inside the module on the thermal conduction radius and thermal diffusion angle is clarified. The thermal impedance matrix is reconstructed with the modified thermal diffusion angle, thus realizing the optimization of the thermal network model of the multi-chip IGBT module. The experimental results show that the junction temperature calculation results of the improved multi-chip IGBT module thermal network model are more in line with the finite element simulation than the traditional unimproved method, thus verifying the validity and accuracy of the model, and laying a solid foundation for the large-scale integrated multi-chip thermal analysis. Theoretical basis.