AC Cycling Testing of SiC MOSFET Power Module

Abstract:
This paper details the development of an accelerated AC cycling test bench for evaluating the aging mechanisms of SiC MOSFET power modules. Contrary to classical HTGS and DGS which only exercise gate source stresses the AC Cycler switched under high voltage and current. Operating for about 235 hours, the system maintained stable thermal conditions thanks to an integrated cooling system. Key precursors of aging, such as increases in threshold voltage and on-state resistance were identified using static characterization curve tracer before and after the test. Gate charge and Vdson were also measured on-line with specially developed gate drivers.