Technical and economical evaluation of modular multilevel converters for the electrical power grid interface

Abstract

Over the past few years, it has been verified a raise in the demand, as well as the price of electricity, urging the need for the development of more efficient power converting systems. Two of the most used power converters are the AC-DC, commonly known as rectifier, and the DC-AC, commonly known as power inverter. There are many different topologies for both the referred converters, but one of the most common is the H-Bridge, which can operate as a bidirectional converter that enables the possibility of a single power converter working either as an active rectifier or a grid-tied power inverter, according to the application in use. In this paper, a Modular Multilevel Converter topology is presented and compared to the most conventional bidirectional power converter, discussing both technical and economical details recurring to simulations and a critic analysis of the results, which allows the understanding of the tied relation between economics and engineering, optimizing the functionality of the converter, as well as the costs associated with R&D and production in short term, and the efficiency in the long term.