Design and Testing of a 13.8 kV/1.1MVA 3-Phase 5-Level Flying Capacitor Converter with 10 kV SiC MOSFETs

The flying capacitor converter receives increasing attention recently for high power density converter design with the emerging SiC and GaN devices. This paper demonstrates a 13.8 kV / 1.1MVA 3-phase 5-level (5L) flying capacitor (FC) converter design with emerging 10 kV SiC MOSFET for medium voltage applications. This paper first focuses on the FC value selection method with the analysis of the relation between capacitor ripples and device blocking voltage operation. The three FCs in 5L FC converter are designed to reduce the total volume of flying capacitors. After the FC values are selected., this paper presents the design of different components including the converter layout arrangement, gate driver design and auxiliary power system design. In this paper, one AC-DC single phase leg is built and tested for verification. The testing of different components is first conducted. The testing result of the phase leg is also shown in this paper.