DocumentCode :
740570
Title :
A Natural DC-Link Voltage Balancing of Diode-Clamped Inverters in Parallel Systems
Author :
Stala, R.
Author_Institution :
Dept. of Electr. Drive & Ind. Equip., AGH Univ. of Sci. & Technol., Krakow, Poland
Volume :
60
Issue :
11
fYear :
2013
Firstpage :
5008
Lastpage :
5018
Abstract :
This paper presents a method of natural dc-link capacitor voltage balancing of three- and single-phase neutral-point-clamped (NPC) inverters working in parallel configurations. It is proven that, in such parallel systems, when the inverters are insulated, the conditions for natural balancing can be achieved, and the application of a balancing circuit can assure the dc-link voltage balance independently on load. The method enables the natural balancing of single-phase single-branch NPC converters where natural balancing conditions do not occur. The application of the method presented in the three-phase NPC converter enables achievement of neutral dc-link voltage balance by the use of only one additional passive RLC circuit. In addition, the concept of lossless balancing in such systems is introduced. In the proposed system, by the application of a balancing circuit with a transformer and by using dedicated pulse with modulation, the balancing current flows in an unbalance state only. The unnecessary components of current that can flow in the balancing circuit are not present in the proposed solution. Simulations and experimental results in a system composed of two parallel inverters are presented to verify the concepts of natural balancing.
Keywords :
invertors; power convertors; transformers; balancing circuit application; diode-clamped inverters; lossless balancing concept; natural DC-Link voltage balancing; natural dc-link capacitor voltage balancing; neutral dc-link voltage balance; parallel inverters; passive RLC circuit; single-phase NPC inverters; single-phase neutral- point-clamped inverters; single-phase single-branch NPC converters; three-phase NPC converter; three-phase NPC inverters; three-phase neutral- point-clamped inverters; transformer; Capacitors; Inverters; Power transformer insulation; Pulse width modulation; RLC circuits; Resonant frequency; Simulation; DC-link voltage balance; multilevel systems; natural balancing; neutral-point-clamped (NPC) inverter;
fLanguage :
English
Journal_Title :
Industrial Electronics, IEEE Transactions on
Publisher :
ieee
ISSN :
0278-0046
Type :
jour
DOI :
10.1109/TIE.2012.2219839
Filename :
6307851
Link To Document :
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