Twelve-pulse multilevel current source inverters for fundamental frequency switching schemes

Abstract

Due to several reasons current source inverters (CSI) are seldom used compared to the voltage source inverter (VSI) principle. On the one hand they need reverse blocking semiconductors, on the other hand their DC-link element is an inductor. Furthermore the topology is affected by the unavoidable resonant behaviour of its output network because of the necessary output capacitors. Until now all efforts to avoid the excitation of this resonance were switching scheme based. This paper provides the time domain solution for a twelve-pulse topology that is by its principle able to avoid the lowest order harmonics and can therefore be operated with every switching scheme, even fundamental frequency ones.