Novel RPWM Selective Harmonic Elimination Approach for Single Phase VSI

Ang, Kai Liang (2022) Novel RPWM Selective Harmonic Elimination Approach for Single Phase VSI. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Inverter is a power electronic converter that can convert Direct Current (DC) to Alternating Current (AC). There are variety of modulation technique for an inverter such as Sinusoidal Pulse Width Modulation (SPWM), Selective Harmonic Elimination PWM (SHE-PWM) and Random PWM (RPWM). However, SPWM will cause high harmonic to accumulate at the switching frequency due to only single frequency appear in the carrier signal. As a result, it will also cause high Total Harmonic Distortion (THD), noises and vibration. RPWM can solve this problem by using a carrier signal with randomly changing frequency. However, RPWM cannot eliminate a selective harmonic, particularly, the resonant frequency of the load. SHE-PWM can only remove low order harmonic. RPWM-SHE is a modulation technique that can evenly distribute the spectrum and at the same time removing the selective harmonic. However, the existing RPWM-SHE will cause higher distortion than the conventional RPWM. Hence, this thesis has proposed a solution by introducing the Genetic Algorithm to optimize the performance of the RPWM-SHE. The proposed work is simulated on Matlab Simulink. The result has shown that the THD is able to reduce to 11.15% on static load and 7.30% on dynamic load. On contrast, the existing RPWM-SHE has 17.86% THD on static load and 12.83% on dynamic load. Besides, the result also shows that the developed work shows promising result in spectrum, noise and vibration performance.