A new high power efficiency cascaded U cells multilevel converter

In this paper, authors presents a novel competitive multilevel converter. The novel cascaded U cells topology is constituted from two power switches and one capacitor for each cell. In case of DC/AC conversion, the proposed fifteen level inverter allows a nearly sinusoidal output voltage resulting on a perfectly sinusoidal load current. In case of AC/DC conversion, the proposed fifteen level rectifier presents a reduced impact on the utility supply, a good energetic efficiency and a small number of power switches and passive components. An average model of the proposed converter is performed and a control strategy is designed in order to draw a nearly sinusoidal current and voltage. Active and passive filters can thus be avoided resulting on a highest energetic efficiency and a reduced installation cost. The proposed converter presents also the possibility and the simplicity of changing the number of voltage levels only by acting online on the ratios of the desired output voltages. The modeling and control strategy of the proposed fifteen level converter were verified by simulation.