A three-phase three-level converter with shared flying capacitors

Abstract

Three-phase multilevel converters use a high number of components which increases their size. As specific weight reduction is a work of interest for embedded system applications, this paper presents a topology aiming to optimize volume and mass for a three-level three-phase inverter named 3L Hybrid. This three-phase topology reduces the stored energy by two-thirds compared with three-level flying capacitor (FC) while keeping the same characteristics. The ‘phase-sharing’ principle allowing the reduction number of FCs is presented and the three-phase 3L Hybrid working will be described. An original closed-loop control method has been developed for this structure. The control solution is generic and can be applied on other common flying capacitor (CFC) topologies. Finally, experimental results are presented and comparative data with well-known multilevel topologies are analysed.