Comparison and analysis of different conduction modes of three phase voltage source inverter

A Simulink model for voltage source inverter using switching function concept is studied with the help of MAT-LAB/SIMULINK in this paper. The switching function concept is a powerful tool in understanding and optimizing the performance of static power converters/inverters. A three phase output can be obtained from a configuration of six IGBT. Three types of control signals can be applied to the switched: 1800 conduction, 1200 conduction or 1500 conduction. The output voltages and current of a three phase voltage-source inverter is studied in this paper. The quality of output voltage can be improved by only changing the conduction mode which is very simple to implement. The switching operation of a three phase inverter is controlled so that output is achieved at every 600 angle in 1200, 1800, 1500 conduction mode. Harmonics are created in the output of these kind of inverter. These harmonics not only reduces the life period of appliances, but also causes excessive wear in the device or appliances used in the day to day life of human being. By analyzing the output harmonic spectra of output voltages and current (line to line current and line to line voltages), their total harmonic distortion (THD) is found and compared.