A Family of Si and SiC devices-based Short Commutation Loop Hybrid-NPC Rectifiers

Abstract

The silicon carbide (SiC)-based converters are emerging as an attractive solution for various industrial and utility scale applications due to their several important features. However, utilization of SiC devices in these systems also suffer from some challenges, such as higher cost, large turn-off overvoltage peaks, and increased conduction losses leading to restricted system performance. In this paper, a family of short commutation loop-based three-level hybrid active neutral-point-clamped rectifier (SCL-HNPCR) comprising SiC MOSFETs and Si/SiC diodes is proposed to address the afore-mentioned challenges. The proposed SCL-HNPCRs not only achieve high efficiency at reduced cost but also offer reduced turn-off voltage peak without adding any external passive components. Moreover, with the proposed control scheme, the SCL-HNPCRs minimize the conduction losses of SiC MOSFETs, mitigate the crosstalk related issues and achieve balanced loss distribution across the switching devices leading to optimized utilization. In this paper, the structure and operating principles of the proposed topology are discussed with the proposed control scheme. Further, analytical and simulation results are presented with the comparative evaluation against the existing NPC-derived rectifiers. Finally, the experimental validation results are demonstrated with the developed prototypes.