Investigation into active-gate-driving performance and potential closed-loop controller implementations for silicon carbide MOSFET modules

Abstract

Active gate driving (AGD) is a promising concept for achieving high-performance power transistor switching. This is particularly crucial for Silicon Carbide (SiC) MOSFETs since their inherently fast switching characteristics give rise to severe overshoots and oscillations which translate into increased levels of electromagnetic interference (EMI) emissions. In this paper, an AGD strategy using a single-pulse applied during the switching transient is considered for a 1200 V 400 A SiC MOSFET module. The effect of single-pulse timing, load current, and temperature on the switching performance is analyzed in detail. The radiated EMI reduction benefits are quantified by H-field and E-field probes. A conceptual closed-loop AGD approach is presented and compared to open-loop operation. For the transistor turn-off case under full load current of 400 A, experimental results show that it is possible to reduce voltage overshoot by 43.3%, voltage and current oscillations by 69.7% and 52.2% respectively, and EMI by 76.6%, with a trade-off in the switching energy by a relatively minor increase of 18.2%, compared to the conventional gate driving case. For the turn-on case, current overshoot was reduced by 32.7%, EMI by 52%, voltage and current oscillations by 54.6% and 52.8%, respectively, with a penalty of 50.9% increase in the switching loss.