Four Level Voltage Active Gate Driver for Loss and Slope Control in SiC MOSFETs

Abstract

Silicon Carbide power semiconductors exhibit fast dynamic behavior. This facilitates the design of high efficiency and high power density converters. However, the resulting current and voltage changing rates demand extensive filtering to avoid electromagnetic interference and ensure safe operation. In addition, temperature fluctuations due to varying load currents from renewable energy sources pose challenges for power semiconductor device lifetime and reliability. Active temperature control can reduce temperature fluctuations, but affects switching slopes simultaneously. This leads to variable electrical stress on both device and circuit level. In this paper, a four-level active voltage-source gate driver for SiC MOSFETs is proposed, enabling manipulation of switching and conduction losses. Switching losses are manipulated by controlling the duration as well as amplitude of intermediate gate voltage pulses during switching transients. Conduction losses can be influenced by adjusting the positive gate voltage. Simulations indicate that the proposed gate driver allows decoupling switching loss and slope control. To validate the gate driver concept, a prototype has been built and evaluated in double pulse test experiments.

Four Level Voltage Active Gate Driver for Loss and Slope Control in SiC MOSFETs