Novel PWM technique for fundamental fortification in voltage source inverters

Abstract

Pulse width modulation (PWM) techniques have been used extensively for DC-AC conversion in voltage source inverters. The domain of PWM techniques has undergone intensive research in the past decades. Of the many characteristics of the inverter, fundamental fortification reduced total harmonic distortion (THD) and reduced switching losses have been prime focuses in the literature. This paper presents a novel PWM technique, which introduces a modified reference as well as a modified carrier used to generate the PWM pattern. The reference is a combination of trapezoidal and third harmonic injection PWM functions. The carrier is a modified inverted sine function. The proposed PWM scheme is implemented and studied for a single phase voltage source inverter (VSI) using MATLAB software. The new PWM enhances the fundamental by 19.35% vis-à-vis the conventional Sinusoidal PWM (SPWM). In addition to fundamental fortification, suppression of lower order harmonics and reduction of THD is noticed. Also, a significant reduction in the inverter's switching has been made by decreasing it to two fifths of a conventional SPWM inverter.