A novel multi-level converter based on current source power cell

A novel N-level converter based on current-source power cells that is suitable for medium to high-voltage power applications is proposed. The topology is mainly the dual of the conventional topology based on voltage-source power cells. As such, it inherits all the advantages of the standard topology. But more importantly, the second current harmonic injected back by the normal operation of the single-phase current-source inverters are naturally cancelled out at the DC side of the power cells. This feature is assured by sharing the same magnetic circuit among the inverters connected to different load phases. As a result, the DC link filter required by the operation of the cell needs to be designed just to filter out the switching harmonics. Differently to voltage-source power cells based N-level converters, this ensures a small filter size, an important feature for medium to high power applications. Moreover, standard modulating techniques can be used such as SPWM, space vector, and Selective Harmonic Elimination without any penalties on the aforementioned advantages. Preliminary results confirm the theoretical considerations.