Open AccessGeneralised overmodulation approach applied to symmetrical and asymmetrical cascaded multilevel converters with faults on the converter power cells
Author(s) -
Carnielutti Fernanda,
Pinheiro Humberto
Publication year - 2019
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2018.8077
Subject(s) - overmodulation , converters , modulation (music) , power (physics) , computer science , control theory (sociology) , electronic engineering , voltage , range (aeronautics) , engineering , pulse width modulation , electrical engineering , physics , control (management) , quantum mechanics , artificial intelligence , aerospace engineering , acoustics
In this work, a generalised hybrid overmodulation strategy for symmetrical and asymmetrical cascaded multilevel converters with faulty cells is proposed. This approach allows the converter to operate with a wider range of modulation indexes even with faults on the power cells, compared with the case where just operation on the linear region is considered. As a result, the operating range of the converter can be expanded. The proposed algorithm simplifies the modulation, as it does not need to calculate and store offline multiple trajectories for the voltage reference, as usually is the case with overmodulation strategies; this task is performed online. Due to the nature of cascaded multilevel converters, two kinds of overmodulation can happen during faults on the converter power cells, which are discussed in this paper. Then, solutions are presented in order to deal with all of these operating conditions. Experimental results with a hardware‐in‐the‐loop platform are given to verify and validate the theoretical analysis.