Destressing MOSFETs by Series Connection in Low Gain Buck Converters

Low-gain buck converters will enable low voltage loads to access high voltage DC sources by a single stage converter at very low duty cycles. SiC MOSFETs are still limited to 1.7kV commercially and by seriesing them with adequate gate driving strategy, high voltages can be switched. This paper proposes a driving circuit for series SiC MOSFETs to block higher voltages. The driving circuit provides negative off-state voltage and turn on/off transitions in less than 100ns. The low-gain buck converter performance is assessed when using a single IGBT switch and series SiC MOSFETs. A simulation is implemented and shows the superiority of the proposed driven series SiC MOSFETs with distributed voltage and thermal stresses.