UIS Characterization of Hybrid Si/SiC Device under Single Pulse Avalanche Mode

For power conversion applications, is has been verified that a more improved trade-off between cost and performance than all-SiC solutions has been provided by hybrid Si/SiC device. To ensure long term reliable operation of power electronics system, the ruggedness and failure mode of the hybrid Si/SiC device has already been experimentally explored under the short-circuit (SC) fault condition. This paper conducts an investigation on Unclamped Inductive Switching (UIS) characteristics of hybrid Si/SiC device under single pulse avalanche mode by experiment tests. The device branch that limits the UIS capability of the hybrid device is identified, and which factors and how the factors affect UIS robustness of the hybrid switch are also extensively discussed. It’s found that the UIS capability is dominated by the IGBT branch which provides the only avalanche current conduction path. Further experimental test shows that a higher case temperature leads to reduction in both the avalanche mode withstand time and avalanche energy, but the avalanche voltage gets increased. In contrast to the case temperature, the turn-off delay time of the auxiliary branch, SiC MOSFET, only has impact on the avalanche energy of hybrid Si/SiC device.