Multistring seven-level quasi Z-source based asymmetrical inverter

Abstract

In this paper, a single-phase multistring <strong>seven-level Quasi-</strong>Z-source based Asymmetrical Inverter suitable for grid-connected photovoltaic (PV) system is presented.<strong> </strong>This topology is <strong>an upgrade of quasi-</strong>Z-source dc-dc (qZs) network and Asymmetrical multilevel inverter (AMLI). The AMLI generates higher number of levels with reduced switch count and number of sources when compared to symmetrical cascaded based MLI. The qZs network acts as an intermediate stage between the low-voltage PV array and AMLI, to enhance the output voltage gain of the inverter. The steady state performance the topology is verified through MATLAB simulation and experimentation. A laboratory prototype model is developed for a capacity of 200W to validate the theoretical studies. Finally, a <strong>c</strong>omparative assessment of the proposed with the existing topologies is presented.

Reduction of common mode voltage for grid-connected multilevel inverters using fuzzy logic controller

“…Cascaded multilevel three-phase inverters are increasing [1]- [8] in industries of renewable energy and electric drives [4], [9]- [13] due to their advantages such as high power capacity, the ability to provide a output voltage similar to sinusoidal waveform [14], and suffer from high voltage shock. Factors significantly affect the inverter output voltage quality consisting of the modulation method, current controllers, and phase-locked loop (PLL).…”