Effect of thermal imbalance on inter-chip oscillations of SiC MOSFETs and their suppression

This paper investigates the influence of thermal imbalance on inter-chip oscillations in parallel-connected SiC MOSFETs. The severe inter-chip oscillations during switching transients present critical instability and challenge for the reliability of power converters. Through theoretical analysis and simulation, this study demonstrates that the inter-chip temperature difference (ΔT) is a primary driver of oscillation severity, rather than the overall operating temperature. Results show a significant positive correlation: the oscillation amplitude increases from 16V at ΔT= 10°C to an unsafe level of 60V at ΔT= 40°C. This paper also reveals a strong coupling between thermal imbalances (ΔT) and electrical parasitic parameters, which mutually exacerbate instability. Finally, this study validates the use of ferrite beads as a robust suppression method that remains effective across a wide range of temperature differences.