Voltage Total Harmonic Distortion Reduction in Multi-level Single-Phase Inverters using the SHE-PWM Technique with a TLBO Algorithm

Abstract

This paper presents a modulation method based on the selective harmonic elimination-pulse width modulation (SHE-PWM) technique. The aim is to determine the optimal switching angles (SA) using the teaching learning-based optimization algorithm (TLBOA), capable of reducing the voltage total harmonic distortion (THD) present in the output waveform of single-phase multi-level inverters (MLIs). The performance of proposed technique has been verified through simulation using Matlab script and Simulink environment. The TLBOA-based SHE-PWM technique is applied to a 17-level inverter to eliminate 5th, 7th, 11th, 13th, 17th, 19th and 23rd harmonics, achieving an improvement of up to 4.31% in the phase voltage THD content in the range of modulation index (MI) 0.5 to 0.95. Furthermore, the superiority of the proposed technique was confirmed by comparison with conventional modulation techniques, which showed that the proposed technique produces lower THD than those used in the equal phase (EP), half-equal phase (HEP), feed forward (FF) and half height (HH) methods.