Modulation Scheme of an Improved 5-Level Current Source Inverter

A 5-level self-balancing current source inverter (CSI) was recently reported. In this inverter, two diodes are used to provide current paths for DC inductors, while they introduce large power loss. Replacing diodes with active switches is a wellproven technology to increase the efficiency of a power converter. However, the use of active switches to replace diodes in this 5-level CSI has a challenge in modulation design. In this work, a novel modulation scheme is developed to accommodate this replacement. By applying the proposed modulation, the 5-level CSI with active switches retains all the advantages of the original version. Experiments are provided to validate the effectiveness of the proposed modulation.