A novel 31-level packed U cells converter

In this paper, the authors present a novel competitive 31-level converter which makes use of small number of power switches and passive components. In case of DC/AC conversion, the proposed 31-level inverter allows a nearly sinusoidal output voltage resulting on a perfectly sinusoidal load current. In case of AC/DC conversion, it presents a reduced impact on the utility supply and a good energetic efficiency. 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 on-line on the ratios of the desired output voltages. The modeling and control strategy of the proposed 31-level converter were verified by simulation. The good performance of the control strategy during steady state and transient regimes is reported.