Unwanted turn-on of SiC JFET bi-directional switches under influence of parasitic parameters

SiC JFET bi-directional switches (BDS) are widely used in construction of matrix converters, multi-level converters, solid state switches, etc. In this research work, the phenomenon of unwanted turn-on (UTO) of SiC JFET-based BDS and its related constant envelop oscillation is investigated. This phenomenon is critical to power conversion systems' stability and reliability. Firstly, the roots of UTO are investigated by probing into the gate drive circuits, some theoretical analysis on the unique configuration of BDS is presented. Then some methods for mitigating the UTO behavior and constant envelop oscillation are proposed. Finally, the effectiveness of the proposed methods is verified by the experimental results.