In Figure 2.1 one phase-leg of a ve-level NPC inverter is displayed. By adding two
identical circuits the three phase-legs can together generate a three-phase signal where
sharing of the DC-bus is possible. Take note that the required number of clamping
diodes are quite high and for higher number of voltage levels the NPC topology will be
impractical due to this fact [2]. The reason for the inverter to have clamping diodes
connected in series is so that all diodes can be of the same voltage rating and be able
to block the right number of voltage levels. For example, in Figure 2.1 all diodes are
rated for Vdc
4 ( Vdc
m