Experimental study of an EMI reduction gate-driver technique for turn-off transition of 1.7 kV SiC MOSFET

Abstract

This paper proposes a novel self-controlled SiC MOSFET gate driver circuit. This new gate driver (GD) proposes a dynamic gate-bias modification thanks to a passive feedback of the drain or source current to control the EMI during turn-off switching transition. A Rogowski coil integrated into the terminals of the SiC MOSFET provides the feedback to modify the gate voltage profile. During turn-off, this circuit increases the voltage level of gate and consequently the gate current. This approach has a positive effect on the EMI behavior of converters without harmful effect on converter efficiency compared to the conventional method which consists in increasing the gate resistance. Moreover, with this approach, the gate driver design remains without modification (except the connection to the Rogowski coil) and there is no effect on turn-on transition of the SiC MOSFET. The proposed method is designed and developed for a 1.7kV SiC MOSFET and has been validated experimentally in an inductive doublepulse test platform. The proposed gate driver moderates the switching speed and is validated experimentally up to 1.2 kV 200A with the 1.7kV SiC MOSFET by reducing the common-mode current of turn-off transition.

A comprehensive analytical description of the asymmetric active snubber

“…Further, empirical experiments may suffer from side-effects like, e.g. electromagnetic interference [13], hardware limitations like suitable current probes [14,15], or simulation convergence and model complexity [16]. Therefore, an analytical description is most appropriate and shall be target of this work.…”

“…FIGURE13 Snubber voltage development over multiple switching events at 50 A, odd numbers are turn-on, even numbers are turn-off…”