Three-Phase Multi-LevelInverter for Grid Connected System with Reduced Power Electronic Components

Abstract

This paper proposes symmetrical three-phase multi string seven-level inverter for various distributed energy resources DERs application. The simplified multilevel inverter requires only nine switches which reduces number of power devices and passive components, and control circuitry when compared to conventional cascaded H-bridge CCHB multilevel inverter. Three phase Cascaded H-Bridge Seven level inverter is interfaced with low frequency transformer with multiple PV Source is proposed. Nowadays multilevel inverter (MLI) plays a vital role in the field of power electronics and being widely used in many industrial and commercial applications. Moreover the advantages like high quality power output, low switching losses, low electro-magnetic interference (EMI) and high output voltage made multilevel inverter as a powerful solution in converter topology. The proposed topology has advantages like smaller filter size, and lower electromagnetic interference. Output harmonics are also reduced and hence total harmonic distortion is reduced. The proposed topology is implemented to grid connected system.Simulation results are shown for voltage and current during synchronization mode and power transferring mode to validate the methodology for grid connection.