Design and Control of A Switched-Diode Multilevel Inverter for Photovoltaic Application

Abstract

Extensive renewable power generation growth has increased the research effort in power converter technology. To improve the power quality in such applications, it is desirable to interface the system with multilevel inverter (MLI) instead of traditional two/three-level inverters. The conventional MLIs however need isolated dc sources with higher switch count. To address this issue, this paper presents a novel reduced switch switched-diode module MLI (SDM MLI). The proposed SDM MLI is designed using n basic repeating units and a half-bridge module. This module enables the MLI to produce 4n+5 voltage levels instead of 2n+3 at the output. In view of switch count, source count, blocking voltage, loss, and design cost, the MLI topologies are compared. Selective harmonic elimination (SHE) technique is used to control the proposed seventeen-level SDM MLI. MATLAB/SIMULINK platform is used for extensive simulation of the SDM MLI in dynamic environment. Furthermore, under different modulation indices, change in frequency and load dynamic conditions, the theoretical and simulated findings are validated experimentally on a prototype developed in the laboratory.