Performance Assessment of 10 kV SiC MOSFET and PiN Diode in 3L-NPC Converter Topology

Abstract:
Medium voltage SiC devices present great potential to be implemented in high-power converters to improve system performance and reduce the number of switches required in multi-level topologies. This work systematically evaluates the performance of 10 kV SiC MOSFETs and PiN diodes in a 3-level NPC topology. The static and dynamic characteristics have been experimentally characterized, and electro-thermal converter simulations were performed to evaluate maximum converter power and system effi-ciency for different switching frequencies. The results show that the converter can operate at high switch-ing frequencies (up to 10 kHz) with an efficiency higher than 99 %. Furthermore, a significant degree of freedom to choose higher switching frequencies designs (500 up to 2000 Hz) without heavily compromising converter efficiency (~ 99.5 % nominal efficiency) and output nominal power (~ 15 % downrating of nominal power with a four times increase in the switching frequency) is demonstrated.