A new AC/AC-multilevel converter family applied to a single-phase converter

A new AC/AC-modular-multilevel converter (M/sup 2/LC) family will be introduced. The new concept stands out due to its modularity as well as its extremely good control characteristics. The stringent modularity results in a very cost-efficient and versatile converter construction. This new M/sup 2/LC concept is well suitable for a wide range of multiphase AC/AC-converters. The basic working principle together with the static and dynamic behaviour are explained in detail on a single-phase AC/AC-converter that enables four-quadrant operation. It is shown that this converter concept is advantageous for future AC-fed traction vehicles and that it fulfils very well their requirements.