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Parallel Voltage Source Converters: Applications, Control, and Modulation Techniques 

Yunwei Li and Zhongyi Quan

Brief Introduction:

    Parallel voltage source converters (VSCs) have been widely employed in various applications like renewable energy systems, drives, and microgrid, with the advantage of modularity, reliability, efficiency, etc. However, high penetration of parallel converters has also imposed severe challenges to design and stable operation of the entire system. Focusing on these challenges, this intermediate level tutorial presents a comprehensive overview of the recent advances in the analyzing approaches and solutions. It is envisaged that this tutorial will provide one-stop information source for researchers interested in the control, operation, and practical implementation of parallel VSCs.

    Starting with an introduction of the applications of parallel VSCs, different system configurations will be reviewed, along with a detailed discussion of the associated challenges. The main challenges are categorized into two types, i.e. low frequency and high frequency issues. For low frequency issues, stability analysis and controller design of LCL-filtered parallel VSCs will be presented, along with the power sharing control and circulating current control. For high frequency issues caused by modulation, the impact of modulation techniques on circulating-current will be examined with a straightforward frequency-domain analysis. Moreover, practical challenges and potential interesting research topics will be discussed in this tutorial.

image.pngYunwei (Ryan) Li received the Ph.D. degree from Nanyang Technological University, Singapore. Dr. Li was a Visiting Scholar with Aalborg University, Denmark, a Postdoctoral Research Fellow at Ryerson University, Canada. He also worked at Rockwell Automation Canada before he joined University of Alberta, Canada in 2007. His research interests include distributed generation, microgrid, renewable energy, high power converters and electric motor drives.

Dr. Li serves as Editor-in-Chief for IEEE Transactions on Power Electronics Letters. Prior to that, he was Associate Editor for IEEE Transactions on Power Electronics, IEEE Transactions on Industrial Electronics, IEEE Transactions on Smart Grid, and IEEE Journal of Emerging and Selected Topics in Power Electronics. Dr. Li received the Richard M. Bass Outstanding Young Power Electronics Engineer Award from IEEE Power Electronics Society in 2013, prize paper award of IEEE Transactions on Power Electronics in 2014. Dr. Li is a Fellow of IEEE.

Dr. Li published over 120 top-tier journal papers and his work is well cited with over 13000 citations (google scholar). He is listed as highly cited researcher by the Web of Science Group.


image.pngZhongyi Quan received the B.Eng. degree from Tianjin University, Tianjin, China in 2010, M.Sc. degree from Beihang University, Beijing, China, in 2013, and Ph.D. degree in electrical engineering in 2019 from University of Alberta, Canada, where he is currently a Postdoctoral Fellow. From Oct. 2019 to Nov. 2019, He was a visiting research fellow at the Institute for Power Generation and Storage Systems (PGS), E.ON Energy Research Center, RWTH Aachen University, Germany.

Dr. Quan is the recipient of the Alberta Innovates Graduate Student Scholarship from 2016 to 2018, the 3rd prize award in 2018 IEEE ECCE Best Student Project Demonstration session, and the APEC student travel award in 2019.

His current research interests include design of high density and high efficiency power converters for applications such as renewable energy, industry motor drive, electric vehicles, etc.

Dr. Quan has been working on the topic of parallel converters for over five years. He has published over 20 technical papers. He will provide his experiences in modulation and design of parallel converters in this tutorial.