Introducing the Common Cross Connected Stage (C3S) for the 5L ANPC multilevel inverter

This paper proposes a novel multilevel power electronics building block (PEBB) for the 5 level ANPC multilevel voltage source inverter [7]. The PEBB is composed of 6 switches in a crossed configuration [8] and one capacitor. It is common to the 3 phases of a 5 level ANPC topology, enabling a large number of levels to be generated, especially uniform voltages steps in 7 and 9 levels configurations. This PEBB is meant to be a reliable upgrade to the 5L topology, increasing output signal quality, and therefore directly contributing in reducing the size of the output filter notably in medium voltage applications. The number of levels generated by the C S PEBB and the ANPC depend on the voltage ratios chosen between the phase capacitors of the ANPC and the PEBB capacitor(s). The trade off stands between ability to balance the capacitors, the rated blocking voltage of the devices and the number of levels produced. Under a given configuration, 9 levels can be produced with the possibility to balance the capacitors up to modulation indexes in the region of m=0.92. The analysis of the general topology, the description of the 9 level case, and simulation results are first presented. Prototyping results are then shown and validate the introduced concept and topology.