A Medium-Voltage Multilevel Hybrid Converter Using 3.3kV Silicon Carbide MOSFETs and Silicon IGBT Modules

In this work, a medium voltage (MV) five-level (5-L) hybrid active neutral-point-clamped (ANPC) converter with the inner-interleaved configuration is proposed featuring improved output quality and ease of filtering design. The proposed hybrid ANPC converter consists of the silicon (Si) IGBT based low switching frequency cells and the silicon carbide (SiC) MOSFETs based high switching frequency cells to achieve low harmonics at premium efficiency and reasonable cost. By adopting the inner-interleaved configuration within SiC high switching frequency cell, the proposed hybrid ANPC has increased voltage levels and much higher equivalent switching frequency compared to the conventional ANPC. To validate the effectiveness of the proposed design, an MV converter is prototyped in this work using 3.3 kV Si IGBT half-bridge modules and custom designed compact 3.3 kV SiC H-bridge modules. The design process of the low inductance SiC H-bridge module is also presented. Finally, both simulation and experimental results are presented to validate the performance of the proposed five-level hybrid ANPC converter.