Voltage Balancing of Four Series-Connected SiC MOSFETs under 2 kV Bus Voltage using Active dv/dt Control

This paper demonstrates the voltage balancing performance and switching behavior of four series-connected SiC MOSFET devices. Both multilevel and two-level topologies are capable of achieving higher blocking voltages in high-power converter applications. Compared to multilevel topologies, two-level switching topologies are of interest due to less complex circuitry, higher density, and simpler control techniques. In order to balance the voltage between series-connected MOSFETs, device turn-off speeds are dynamically controlled on each gate-driver with active gate control. The implementation of the active gate control technique is described in this paper. Experimental results of the voltage balancing behavior across four non-commercial 1.7 kV SiC MOSFET devices in series (2 kV total dc bus voltage) with the selected active dv/dt control scheme are shown.