Abstract – The medium voltage adjustable speed drives are a trend for high power applications. The products released in the last decade showed maturity of the technology and brought more confidence to use medium voltage converters in industry applications. Besides high power capability, some segments require optimized footprint for the machines installed inside the plant site. This factor is pushing the development of a branch of new voltage source converters, called Transformerless Voltage Source Drives. These converters bring the possibility to operate the system without phase shift transformers in the connection with the power supply. This paper discusses the well-known topologies applied to medium voltage high power converters, their characteristics, requirements and drawbacks of them. In addition, it is discussed the recent presented topologies applied to transformerless converters, with their challenges and recent developments, pointing a best understand of this new branch of converters.
Joable Andrade Alves received B.S. and M.S. degrees in electrical engineering from the Federal University of Santa Catarina, Florianópolis, Brazil, in 1994 and 1996, respectively. In 1996 he has joined WEG (Brazil) in the Department of Development of Products as R&D engineer. He participated of the development of low and medium voltage variable frequency drives (VFDs) during 12 years. From 2008 to 2013, he worked with the Technical Sales & Application Department where he was responsible for the international support of medium voltage drives. Since 2013, he has been working again at R&D Department where he is coordinator of a group responsible for the development of medium voltage variable frequency drives.