Simulation Model of a Three Phase Multilevel Inverter for a Grid Connected Photovoltaic System

This paper presents a novel approach for the connection of renewable energy sources to the utility grid. Due to the increasing power capability of the available generation systems, a three-level three-phase neutral-point-clamped voltage-source inverter is selected as the heart of the interfacing system. Solar Energy is one of the favorable renewable energy resources and the multilevel inverter has been proven to be one of the important enabling technologies in photovoltaic (PV) utilization. The inverter is capable of producing multilevel of output voltage from the dc supply voltage. With multilevel inverters harmonic content gets reduced and with more levels the output approaches the sine wave. The voltage stress also gets reduced. This work presents simulation of three phase multilevel inverter for standalone applications. Multilevel voltage source inverters offer several advantages compared to their conventional counterparts. By synthesizing the AC output terminal voltage from several levels of voltages, staircase waveforms can be produced, which approach the sinusoidal waveform with low harmonic distortion, thus reducing filter requirements. The need of several sources on the DC side of the converter makes multilevel technology attractive for photovoltaic applications.