Harmonic diminution in unique inverter using particle swarm optimization algorithmic switching angles

Harmonics are undesirable currents and voltages in the power supply system and the sources responsible for the undesirable harmonics are the nonlinear loads like rectifiers, inverters, solid state voltage regulators, cycloconverters and uninterrupted power supplies. This paper demonstrates how the Total Harmonic Distortion (THD) diminution in the output voltage of unique multilevel inverter is achieved. In multilevel inverters with a fundamental frequency switching strategy (each switch turning on and off once per output cycle), the optimum switching angles can be selected so that the output THD is minimized. To obtain the optimum switching angles, an optimization algorithm is applied to the output voltage THD. The new topology has the advantage of its reduced number of devices compared to conventional cascaded H-bridge multilevel inverter and can be extended to any number of levels. This paper deals with the analysis and simulation of a nine level inverter. The harmonic reduction is achieved by selecting appropriate switching angles by particle swarm optimization algorithm. The functionality verification of a nine level inverter is done using MATLAB. The simulation results indicate superiority of this approach over the commonly used phase voltage THD minimization approach.