Five-Level Z-Source Neutral-Point-Clamped Inverter

This paper proposes a five-level Z-source neutral-point-clamped (NPC) inverter with two Z-source networks functioning as intermediate energy storages coupled between dc sources and NPC inverter circuitry. Analyzing the operational principles of Z-source network with partial delink shoot-through scheme reveals the hidden theories in the five-level Z-source NPC inverter unlike the operational principle appeared in the general two-level Z-source inverter, so that the five-level Z-source NPC inverter can be designed with the modulation of carrier-based phase disposition (PD) or alternative phase opposite disposition (APOD) technique. To verify the theoretical findings and practical issues, a scaled down laboratory prototype was constructed and tested with a 1.3 kw induction motor load.