Series connected SiC-MOSFETs voltage balancing:
two methods with adaptative delays


Power-electronics converters for energy transmission in Medium Voltage Direct Current (MVDC) require High-Voltage switches from 10 to 30 kV. Series-connection of SiC-MOSFETs is an effective alternative to achieve less complex High voltage converters. Nevertheless, Voltage balancing during switching transient remains the main challenge. Passive balancing solutions significantly increase the switching losses unlike active voltage balancing. This paper presents different embedded measurement techniques in an active gate-driver that adjusts switching delay in real-time. A measurement based on low-cost voltage comparators is compared to another based on 12-bit Analog-To-Digital-Converter. Both methods present advantages and the experimental results highlight the differences in performance. This analysis shows that acceptable voltage balancing can be achieved even with extremely simple measurements.

Cedric Mathieu-de-Vienne, Besar Asllani, Bruno Lefebvre, Pierre Lefranc, Pierre-Olivier Jeannin

Presented at IWIPP 2022