Passive balancing of the DC bus midpoint for Neutral Point Clamped (NPC) based Voltage Source Converters

Author

Laka, Aitor ; Andoni Barrena, Jon ; Chivite-Zabalza, Javier ; Rodriguez, M.A.

Author_Institution

Comput. & Electron. Dept., Mondragon Univ., Mondragon, Spain

fYear

2013

fDate

10-13 Nov. 2013

Firstpage

1148

Lastpage

1153

Abstract

This paper presents a passive method to balance the voltage of the split capacitors in Neutral Point Clamped (NPC) based Voltage Source Converters (VSC). The voltage of the two capacitors is equated by connecting a low VA transformer at the AC side of the converter. The transformer is connected in wye configuration and its neutral point is connected to the DC side midpoint through a resistance and an inductance. By doing so, it is assured that the mean voltages of the DC side capacitors are balanced. In addition, this method is independent to the load and therefore the balancing is assured under any working point of the converter. The VSC and the balancing circuit have been simulated in the simulation tool Saber and the good performance of the balancing circuit has been validated experimentally in a 6.7KVA test bench.

Keywords

capacitors; flexible AC transmission systems; power convertors; DC bus midpoint; DC side capacitors; Saber simulation tool; VA transformer; balancing circuit; neutral point clamped based voltage source converters; passive balancing; split capacitor balancing; wye configuration; Capacitors; Harmonic analysis; Inductance; Power conversion; Topology; Voltage control; Neutral Point Clamped; Split Capacitors balancing; Voltage Source Converter;

fLanguage

English

Publisher

ieee

Conference_Titel

Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE

Conference_Location

Vienna

ISSN

1553-572X

Type

conf

DOI

10.1109/IECON.2013.6699294

Filename

6699294