A new nine level symmetrical inverter derived from seven level inverter

Abstract

Multi-level inverters are playing a major role in renewable energy connected micro grids. Electricity requirement of customers connected to the micro grid mainly depends on the reliability of multi-level inverter connected to the renewable energy sources. This paper proposes anew topology of cascaded multi-level inverter that utilizes less number of switches and sources than conventional topology. With the usage of less number of switches there is a reduction of number of gate driver circuits used and fewer switches are utilized for specific interval of time. This paper investigates and analyses different multicarrier PWM methods for a single phase nine level cascaded inverter in this CMLI 6 switches and 4 D.C sources are used. In this paper, a CMLI is controlled with Sinusoidal PWM technique with Alternative Phase Opposition Disposition, phase Disposition, Phase Opposition and Disposition, and a new hybrid PWM technique Alternative Phase Opposition and Disposition with Variable Frequency (APOD +VF) are used. Variation of Total Harmonic Distortion (THD) in the outputs and switching losses of the new MLI is compared with conventional cascaded MLI and other existing 7 level reduced switch topologies. The results are validated using MATLAB/SIMULINK.