**5. Comparative Analysis**

This section presents the results of the comparison of different characteristics discussed and verified above. Figure 12 shows a diagram that includes several parameters for the 2L QZSI and the 3L NPC QZSI: volume of capacitors, volume of inductors, summarized voltage stress across semiconductors, heatsink volume, and CEC efficiency.

**Figure 12.** Comparative diagram for the 2L QZSI and 3L NPC QZSI.

As can be seen, the equivalent inductances and capacitances of the QZS-stage are practically equal. It is explained by the same operation conditions of the proposed solutions and the same switching frequency. In the case of the 3L NPC, the capacitors and inductors are split, but the overall size remains the same.

The main difference concerns semiconductors. Overall voltage stress across full bridge transistors remains the same, but the 3L NPC requires additional clamping diodes. It was also clearly shown, that due to the higher operation temperature of the SiC devices in 2L QZSI, the heatsink can be selected significantly smaller.

Finally, the diagram also shows that power losses (1-CEC) are slightly smaller in the 2L QZSI than in the 3L NPC QZSI. It was achieved even under the higher operation temperature of SiC semiconductors.
