A decoupled Nearest Level Control for a Modular Multilevel Cascade Converter based on Triple Star Bridge Cells (MMCC-TSBC)

Abstract

The Modular Multilevel Matrix Converter (M3C), also known as Triple Star Bridge Cells (TSBC) converter from the family of Modular Multilevel Cascade Converter (MMCC) has attracted attention in medium/high voltage, high power applications. Recent research has identified its potential for various direct high power AC/AC conversion applications due to its modularity, redundancy and high power quality. However, it suffers from cross-coupling while utilising low/fundamental frequency switching techniques such as Nearest Level Control (NLC) along with the double αβo transformation. This article proposes a decoupling approach to eliminate the coupling effect and low frequency oscillation at the output port for implementation of NLC in an MMCC-TSBC converter.