Flying Capacitor MultiCell Converters with Reduced Stored Energy

Flying capacitor multilevel converters (FC) have been introduced in the 90's and have given a certain number of industrial converters. Most of these products use the three-cell four-level configuration, then come the two-cell and to a lesser extent the four-cell, but although the principle can be extended to any number of cells there is not a single application using five cells or more. There is however a need for converter with five semiconductors in series or more, but today the number, size and cost of the flying capacitors limits the use of this topology to four-cell maximum. In a first section, modified topologies with less capacitors but producing the same waveforms as FC converters will be presented and classified. In a second section, topologies with a lower component count and providing a priori a lower harmonic performance are listed and compared to the previous topologies.