Loss Analysis of SiC-based Three-Level Active Neutral-Point-Clamped Inverters under Different Modulation Schemes

In this paper, the power losses of three-level active neutral-point-clamped (3L-ANPC) inverters fully utilizing silicon-carbide (SiC) MOSFETs are studied and compared under three typically modulation schemes (i.e., the outer mode, inner mode, and full mode). Double-pulse tests (DPTs) are performed on a 3L-ANPC inverter prototype to evaluate the switching losses of SiC MOSFETs. The overall conversion losses subject to the three modulation schemes are investigated considering device junction temperatures. Accordingly, loss distributions among SiC devices are obtained, and the devices subject to the most significant electro-thermal stresses are identified. A power-loss comparison exhibits a comparable loss performance between the outer-mode and inner-mode modulation methods, while the full-mode loss characteristic is quite dependent on its loading condition. Finally, the theoretical finding presented in this work are validated through experimental measurements of the conversion efficiencies.