Efficiency Comparisons of Two-level and Three-level GaN/SiC based Converters

The efficiency and power density of power electronics converter can easily be improved through the utilization of wide bandgap (WBG) devices. Meanwhile, by growing the diversity of WBG devices, it becomes challenging to select an optimum topology with proper switching frequency to reach an efficient and compact design. Owing to the superior performance of enhancement mode gallium-nitride (GaN) transistors and Silicon Carbide (SiC) MOSFETs, this paper presents efficiency comparisons for GaN/SiC based two-level and three-level converters. Three widely industrial used voltage source converter (VSC) topologies are chosen in this study (1) two-level half-bridge converter, (2) three-level T-type converter, and (3) three-level active neutral-point-clamped (ANPC) converter. Three cases based on different modulation techniques are considered for the comparisons. To verify the results, a prototype of ANPC is built and measured efficiencies are compared with the calculated results.