A new structure of single-phase two-stage hybrid transformerless multilevel PV inverter

Abstract

Transformerless inverters are becoming popular for grid‐connected photovol taic applications due to their simplicity, reduced size, weight, cost, and higher efficiency. In this paper, a two‐stage hybrid transformerless multilevel inverter (MLI) for single‐phase grid‐connected photovoltaic power generation system (PVPGS) is presented. The proposed topology comprises a multilevel boost con verter (MLBC) and a symmetrical hybrid MLI. MLBC combines the boosting and switched capacitor voltage functions to produce self‐balanced multiple voltage levels. The proposed MLI is derived from a combination of bidirec tional switches, a half bridge, and a diode‐clamped branch, which can produce only two variations in the total common mode voltage and is capable of sup pressing leakage current as per DIN VDE 0126‐1‐1 grid standards. It offers the advantages of scalability, reactive power capability, reduced total harmonic distortion, and filter size. The proposed hybrid transformerless seven‐level inverter is simulated in MATLAB, and experimental setup is built to validate the effectiveness of the proposed configuration. Finally, a comprehensive com parison is made with other seven‐level inverter topologies