Back-to-back system for five-level converter with common flying capacitors

This study proposes a novel 5-level converter topology in which common flying capacitors (FCs) are shared by three phases. This circuit can output voltage patterns prohibited in the circuits of the previous study. Furthermore,a back-to-back (BTB) configuration can be realized by only increasing the number of the phase units of the 5-level converter. This BTB system employs common FCs for all input and output. This study shows the topology of a 5-level converter and its operational principle as well as the expansion method for realizing the BTB system. A simulation is conducted to verify the control method and operation properly.