A New Basic Unit for Symmetric and Asymmetric Cascaded Multilevel Inverters with Reduced Power Electronic Devices

Abstract

In this paper, a new basic unit for the cascaded multilevel inverter is proposed. By series-connected numbers of the proposed basic unit, a new cascaded multilevel inverter is also proposed. In order to generate all (even and odd) voltage levels two new algorithms to determine the magnitude of dc voltage sources are proposed. Then, this inverter is compared with several conventional cascaded multilevel inverters that have been presented in the literature. Based on these comparisons, the proposed inverter is able to generate a higher number of output levels by using a lower number of power electronic devices, dc voltage sources and minimum variety of the value of dc voltage sources. As a result, high efficiency, reducing the size and cost of the inverter is the other advantages of the proposed inverter. Finally, the accuracy performance of the proposed cascaded inverter to generate all voltage levels is verified through experimental results on a 49-level inverter in a laboratory prototype. Keywords-Basic unit; multilevel inverters; cascaded multilevel inverter; power electronic devices I.

A Switched-DC Source Sub-Module Multilevel Inverter Topology for Renewable Energy Source Applications

“…The cascaded MLI configurations in the literature have been presented in three categories: switched DC source multilevel inverters (SDC-MLIs), switched-diode multilevel inverters (SD-MLIs), and switched capacitor multilevel inverters (SC-MLIs). The SDC-MLIs use multiple independent DC voltage sources, the SD-MLIs use lots of discrete diodes which are replaced by switches and SC-MLIs use several capacitors with one DC source to reduce the number of power switches [8]- [11]. In this article, the focus is on the presented topologies of SDC-MLIs, in which the weaknesses and strengths are discussed in the following.…”

“…To achieve a large number of voltage levels, all types of multilevel inverters and their cascaded topologies require a high number of components, which causes some technical issues such as: increasing the final system cost, increasing the probability of device failure, and requiring each switch VOLUME 4, 2016 to a driver circuit. To overcome these issues, there has been work on the design of alternative MLI configurations [8]- [11]. These configurations lead to a reduction in the active component count over conventional cascaded MLI configurations.…”