A current symmetrical hybrid multilevel DC-AC converter

This work presents the analysis of new symmetrical hybrid current source-type multilevel inverter topologies. A three-level current cell (TCC) and its respective modulation pattern are proposed. The purpose of the circuits presented here is to reduce current stresses that affects the power semiconductor devices and improve harmonic distortion of the voltages applied to the load. This is done by distributing currents among the switches in the three-level cell. As a characteristic of the proposed cells, some of the switches operate at low frequency while others are switched at high frequency. To validate the operating principle a single-phase circuit has been simulated, operating at 1.0 kHz for the fast switches and 50 Hz for the slow switches. Also featured in this paper is the extension to three-phase versions of the proposed converter.