Novel three phase seven level PWM converter

In this paper, authors propose a novel three phase seven level converter which results from a series connection of the new cascaded U cells and the neutral point clamped NPC topologies. A topological optimization of this configuration leads to the proposed scheme characterized by the use of only eight power switches per phase. Modeling, modulation and control technique of the proposed converter are performed in order to draw a nearly sinusoidal lines currents and line-to-line voltages. A method for balancing DC link output voltages is also proposed in order to protect loads, passives and actives power devices. The proposed three phase seven level converter with its control and balancing techniques were verified by simulation.