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Voltage balancing strategy for a five-level flying capacitor converter using phase disposition PWM with sawtooth-shaped carriers

Authors :
Amer M. Y. M. Ghias
Josep Pou
Mihai Ciobotaru
Vassilios G. Agelidis
Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica
Universitat Politècnica de Catalunya. TIEG - Terrassa Industrial Electronics Group
Universitat Politècnica de Catalunya. (TIEG) - Terrassa Industrial Electronics Group
Source :
IECON, Recercat. Dipósit de la Recerca de Catalunya, instname, UPCommons. Portal del coneixement obert de la UPC, Universitat Politècnica de Catalunya (UPC)
Publication Year :
2012
Publisher :
IEEE, 2012.

Abstract

The flying capacitor (FC) multilevel converter has attracted a great deal of interest in the recent years because of its easier extension to a higher number of levels (n>;3), as compared to its counterpart, the diode-clamped converter (DCC). The main focus of this paper is to develop a voltage balancing scheme of FCs for a five-level FC converter based on phase disposition pulse-width modulation (PD-PWM). Since there are multiple states that produce the same output voltage at the leg of the converter, such a redundancy is used to regulate the FC voltages at their desired levels. The selection of the optimal states is performed by minimizing a cost function. A drawback observed when using standard symmetrical triangular carriers for the PD-PWM, is the additional switching events that are produced due to transitions within the same voltage level. Nevertheless, this fact can be avoided by using sawtooth carrier waveforms instead. Simulation results verify the robustness of the proposed voltage balancing scheme against static and dynamic load conditions. Moreover, using sawtooth carriers a significant reduction of the switching frequency is achieved as compared to the use of standard triangle carriers while maintaining the FC voltage balanced.

Details

Database :
OpenAIRE
Journal :
IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society
Accession number :
edsair.doi.dedup.....cb054e09e5b93d70cd0c03b62f01690e