An Improved Multilevel Inverter for Single-Phase Transformerless PV System

A single-phase Three-Level Split-Inductor Neutral Point Clamped Inverter-Improved (3L-SI-NPCI2) for transformerless photovoltaic (PV) application is proposed in this article. The proposed inverter utilizes two split inductors, which eliminate the shoot-through issue. Therefore, it is more reliable than conventional converters. Not needing dead time, achieving a high efficiency with lower current THD and low leakage current are other advantages of the proposed inverter. The operation principle, dynamic performance, output filter design and impacts of asymmetric filter inductors on leakage current are illustrated in the 3L-SI-NPCI2. The proposed topology is compared to seven existing transformerless topologies by simulation studies and results. Finally, an experimental prototype has been developed to show the benefits of the proposed inverter.