Modular Double-Cascade Converter
Sankala, Arto (2015-06-04)
Väitöskirja
Sankala, Arto
04.06.2015
Lappeenranta University of Technology
Acta Universitatis Lappeenrantaensis
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-265-791-6
https://urn.fi/URN:ISBN:978-952-265-791-6
Tiivistelmä
Medium-voltage motor drives extend the power rating of AC motor drives in industrial applications.
Multilevel converters are gaining an ever-stronger foothold in this field. This
doctoral dissertation introduces a new topology to the family of modular multilevel converters:
the modular double-cascade converter.
The modularity of the converter is enabled by the application of multiwinding mediumfrequency
isolation transformers. Owing to the innovative transformer link, the converter
presents many advantageous properties at a concept level: modularity, high input and output
power quality, small footprint, and wide variety of applications, among others. Further, the
research demonstrates that the transformer link also plays a key role in the disadvantages of
the topology.
An extensive simulation study on the new converter is performed. The focus of the simulation
study is on the development of control algorithms and the feasibility of the topology. In particular,
the circuit and control concepts used in the grid interface, the coupling configurations
of the load inverter, and the transformer link operation are thoroughly investigated. Experimental
results provide proof-of-concept results on the operation principle of the converter.
This work concludes a research collaboration project on multilevel converters between LUT
and Vacon Plc. The project was active from 2009 until 2014.
Multilevel converters are gaining an ever-stronger foothold in this field. This
doctoral dissertation introduces a new topology to the family of modular multilevel converters:
the modular double-cascade converter.
The modularity of the converter is enabled by the application of multiwinding mediumfrequency
isolation transformers. Owing to the innovative transformer link, the converter
presents many advantageous properties at a concept level: modularity, high input and output
power quality, small footprint, and wide variety of applications, among others. Further, the
research demonstrates that the transformer link also plays a key role in the disadvantages of
the topology.
An extensive simulation study on the new converter is performed. The focus of the simulation
study is on the development of control algorithms and the feasibility of the topology. In particular,
the circuit and control concepts used in the grid interface, the coupling configurations
of the load inverter, and the transformer link operation are thoroughly investigated. Experimental
results provide proof-of-concept results on the operation principle of the converter.
This work concludes a research collaboration project on multilevel converters between LUT
and Vacon Plc. The project was active from 2009 until 2014.
Kokoelmat
- Väitöskirjat [996]