A New AC/AC Multilevel Converter Family

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