A Novel Electrical Evaluation Approach for Inhomogeneous Current Distribution in Parallel-Connected IGBT Modules

Inhomogeneous current distribution in IGBT modules exists as an inevitable and critical problem for a long time, which brings great risks during applications. Currently, no non-destructive methods exists to evaluate inhomogeneous current distribution in IGBT modules. A novel electrical evaluation approach is proposed in this paper. The proposed approach creatively applies the excessive thermotaxis effect of low currents for IGBT modules, and makes use of several IGBT characteristics to design a set of test circuits and methods to capture, enhance and finally evaluate the non-uniform property of the transient current distribution of IGBT modules.