DocumentCode :
1878737
Title :
A multilevel power conversion scheme for nonisolated DC sources
Author :
Vassallo, J. ; Clare, J.C. ; Wheeler, P.W.
Author_Institution :
Nottingham Univ., UK
Volume :
5
fYear :
2004
fDate :
20-25 June 2004
Firstpage :
3534
Abstract :
This paper is concerned with the design of a 10-15 MW power conversion scheme required to interface rechargeable, nonisolated DC Sources to the utility grid at medium-voltage. In order to meet application requirements, a 7-level H-bridge inverter topology using series-cascaded single-phase power transformers is proposed. Equalised-power selective harmonic elimination PWM is applied to the inverter, thereby maintaining a low switching-frequency whilst meeting utility grid harmonic requirements. Transformer-cascading allows three-phase voltage generation using H-bridges connected to a single DC-link, thereby cancelling the twice-fundamental current pulse associated with such an inverter, and hence reducing the current ripple on the DC-link. Bidirectional multiphase DC-DC boost converters are utilized to maintain a stabilized voltage on the DC-links and control the power flow from and to the DC sources. A low switching-frequency is also employed on the DC-DC converters and current interleaving reduces the DC source current ripple. A 5 kVA laboratory prototype based on the high power design has been built and is currently undergoing testing. Experimental results are presented in this paper.
Keywords :
DC-DC power convertors; PWM invertors; bridge circuits; harmonics suppression; load flow control; power conversion harmonics; power transformers; switching convertors; 10 to 15 MW; 5 kVA; 7-level H-bridge inverter topology; DC-link; PWM; bidirectional multiphase DC-DC boost converters; current pulse; current ripple; harmonic elimination; medium-voltage utility grid; multilevel power conversion scheme; nonisolated DC sources; power flow control; pulse width modulation; series-cascaded single-phase power transformers; switching-frequency; three-phase voltage generation; transformer-cascading; utility grid harmonic requirements; DC-DC power converters; Medium voltage; Power conversion; Power transformers; Pulse generation; Pulse inverters; Pulse transformers; Pulse width modulation inverters; Topology; Voltage control;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Power Electronics Specialists Conference, 2004. PESC 04. 2004 IEEE 35th Annual
ISSN :
0275-9306
Print_ISBN :
0-7803-8399-0
Type :
conf
DOI :
10.1109/PESC.2004.1355100
Filename :
1355100
Link To Document :
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