Abstracto

Elimination Of Harmonics In A Multilevel Inverter With Unequal Dc Sources Using Bee Algorithm

Saranya R, Maheswari A and Gnanambal I

This work approximates the selective harmonic elimination problem using Bee algorithm to generate the switching angles in a 7-level cascade multilevel inverter. This paper focuses on elimination of harmonics in a multilevel voltage-source inverter with unequal (asymmetric) DC sources. This new topology has the advantage of its reduced number of switches compared to conventional cascaded Hbridge multilevel inverter, and can be extended to any number of levels. Such that the switching losses and switch stress are reduced comparatively. The angles were chosen such that the fundamental was kept constant and the low order harmonics were minimized or eliminated. Artificial Bee Colony (ABC) algorithm is one of the most recently introduced swarm-based algorithms. ABC simulates the intelligent foraging behavior of a honeybee swarm. The main objective of harmonic elimination is to reduce the total harmonic distortion (THD) in the output voltage waveform. The basic concept of this reduction is to eliminate specific harmonics, which are generally the lowest orders, with an appropriate choice of switching angles. Bee algorithm is used to solve the transcendental equations for finding the switching angles. This algorithm can be used for any number of voltage levels without complex analytical calculations. Simulation results for 7-level inverter verify the validity and effectiveness of the proposed algorithm