Performance Analysis and Topology of Neutral-Point-Clamped (NPC) Three-Level Inverter Based on O-Z-Source Impedance Network

To address the issues of conventional Z-source in verter(ZSI), insufficient boosting capacity, high capacitor voltage stress and large starting impulse current, a novel NPC three level inverter (O-ZSI) topology is proposed based on the O type Z-source impedance network. First, a steady-state analysis of the new O-Z-source inverter topology structure is conducted, deriving expressions for the DC-link output voltage and capacitor voltage for this topology. Small-signal perturbation analysis is then applied to characterize the DC-side dynamic behavior. Second, compared with the characteristics of common traditional Z source three-level inverter, the new O-Z-source three-level inverter offers the advantages of lower capacitor voltage stress, higher output voltage boosting capability, and reduced inductance current shock. Then, it is subjected to simple boost control (SBC) to analyze the voltage boosting capability of the new O-ZSI. Finally, through Matlab software simulations and experimental platform, the superiority of the proposed novel O-Z-source three-level inverter is verified. The results demonstrate that the improved Z-source inverter proposed in this paper exhibits stronger boosting capacity, making it suitable for high-output-voltage applications. Additionally, it features lower capacitor voltage stress and can effectively suppress startup inrush current to a certain extent.