A Hybrid Active Neutral-Point-Clamped Converter for Medium-Voltage High-Power applications using Si and SiC devices

Abstract

Recently introduced Silicon carbide (SiC) devices have significantly improved the performance of the power electronic converters. These devices are able to provide higher power density with high efficiency compared to the Silicon (Si) devices. In this paper, the topology based on Si IGBTs and SiC MOSFETs is proposed to achieve high efficiency with reduced cost. The proposed converter achieves zero current switching of Si IGBTs for all power factor values using the selected switching states in the proposed modulation scheme. Therefore, high efficiency can be obtained even at high switching frequency operation for wide range of operating conditions. Additionally, the utilization of the SiC MOSFETs further reduces the switching losses. Moreover, the conduction losses of the SiC MOSFETs are minimized by strategically selecting the switching states in such a way that SiC MOSFETs conduct in parallel conduction paths during the null state operation. This paper presents the detailed operating principle of the proposed topology using the presented modulation scheme. Further, a switching loss analysis is presented to evaluate the conduction and switching losses of the proposed topology. Moreover, the experimental results are presented to demonstrate the basic operating principle of the proposed topology. Finally, the efficiency values of the proposed topology are compared with the existing topologies for different operating conductions.