A New Single-Phase High Step-Up Active-Switched Quasi Z-Source NNPC Inverter With Common Ground Feature

Abstract

Quasi-Z source (qZS) multilevel inverters have become popular in sustainable energy systems, particularly in photovoltaic (PV) systems. This study proposes a qZS five-level nested neutral point clamped (5L-NNPC) inverter, benefiting from continuous input current, high voltage gain, and insignificant voltage stress across semiconductors. The proposed topology provides a common ground between the input sources and the inverter's DC link, thus entirely eliminating leakage current, making it a suitable candidate for PV applications. Moreover, model predictive control (MPC) is employed to regulate the voltages of flying capacitors and the output current of the 5L-NNPC inverter. The study also includes analyses of steady-state performance, circuit design, efficiency, and control considerations. Finally, experimental results are presented to validate the converter's performance.

Keywords

• Five-level nested neutral point clamped
• model predictive control
• quasi Z-source (qZS)