A novel hybrid Phase Shifted-Modifled Synchronous Optimal Pulse Width Modulation based 27-level inverter for grid-connected PV system

摘要

In grid connected Photovoltaic (PV) systems, Multilevel Inverters (MLI) are commonly employed for providing better reliability and getting minimal harmonics. Most of the MLIs function with Phase-Shifted Pulse Width Modulation (PSPWM) techniques for achieving high level performance. However, in the in existing PSPWM techniques, the harmonic voltage profiles are not efficient. This paper aims to improve the harmonic voltage profile of the 4 KW grid-connected PV system using a novel hybrid PSPWM-Modified Synchronous Optimal PWM (PS-MSOPWM) technique for a 27-level inverter. With the combination of these hybrid PSPWM-Modified SOPWM techniques, optimum switching angles are computed to match the switching frequency with the fundamental frequency. From the results, it is identified that the proposed hybrid modulation method effectively reduces the Total Harmonic Distortion (THD) and exhibits improved reliability of the grid-connected solar system. (C) 2019 Published by Elsevier Ltd.