Thermal cross-coupling effect analysis of multi-chips IGBT models considering chip size

Abstract

With the increasing demand of high capacity of power converter, multi-chips IGBT modules are widely applicated. Taking thermal cross-coupling (TCC) effect among IGBT chips into account, the uneven temperature distribution should be investigated in-depth. Thus, in this paper, a steady-state finite-element model (FEM) of a conventionally utilized IGBT module in thermal domain is developed to analyse the effective heat transfer area from the chip to baseplate of the IGBT module. Moreover, the TCC coefficient is proposed in the light of effective transfer area to quantify the TCC effect. The influence of power loss distribution, heat dissipation ability and chip size on the TCC effect is discussed in the end. The results show larger power loss on neighbouring chips and smaller equivalent heat transfer coefficient (EHTC) cause larger TCC coefficient. Chip size has negligible influence on TCC effect at low EHTC, while larger chips size leads to severer TCC effect at high EHTC.