A Negative-sequence Current Injection Method to Mitigate Voltage Imbalances in Microgrids

Gustavo M. S. Azevedo; Joan Rocabert; Marcelo C. Cavalcanti; Francisco A. S. Neves; Pedro Rodriguez

doi:10.18618/REP.20114.296303

Authors

Gustavo M. S. Azevedo Federal University of Pernambuco (UFPE - DEE), Recife - Brazil
Joan Rocabert Technical University of Catalonia (UPC), Barcelona - Spain
Marcelo C. Cavalcanti Federal University of Pernambuco (UFPE - DEE), Recife - Brazil
Francisco A. S. Neves Federal University of Pernambuco (UFPE - DEE), Recife - Brazil
Pedro Rodriguez Technical University of Catalonia (UPC), Barcelona - Spain

DOI:

https://doi.org/10.18618/REP.20114.296303

Keywords:

Distributed generation systems, microgrids, Unbalanced Load

Abstract

This paper proposes a control strategy to reduce the voltage imbalances by injection of a proper negative-sequence current into the microgrid. This task can be done by each inverter connected to the microgrid in a shared way. The current compensation reference is obtained through a negative-sequence voltage control loop, avoiding the load current measurement. The detection of the negative-sequence voltage, at the converter connection point, is performed by a double second order generalized integrator, properly tuned for this purpose. Besides, a current limiter is used to limit the current compensation and avoid the converter overload. This strategy neither requires any hardware modification of the converter nor additional sensors. This new control strategy is simulated in Matlab/Simulink and experimental results are presented to prove its effectiveness.

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Author Biographies

Gustavo M. S. Azevedo, Federal University of Pernambuco (UFPE - DEE), Recife - Brazil

was born in Belo Jardim, Brazil, in 1981. He received the B.S., M.S. and Ph.D. degrees in electrical engineering from the Federal University of Pernambuco in 2005, 2007 and 2011, respectively. He worked as a visiting scholar at the Polytechnical University of Catalunya, Barcelona, Spain, from 2008 to 2009. His research interests are renewable energy systems and microgrids.

Joan Rocabert, Technical University of Catalonia (UPC), Barcelona - Spain

was born in Barcelona, Spain. He received the M.Sc. and the Ph.D. degrees in electrical engineering from the Technical University of Catalonia, Barcelona, Spain, in 2003 and 2010, respectively. From 2004 to 2008, he was a Research Assistant in the Department of Electronic Engineering, Technical University of Catalonia, where since 2008 he has been a Researcher and an Assistant Professor with the Department of Electrical Engineering. His research interests are power electronics applied to PV and wind energy systems and microgrids.

Marcelo C. Cavalcanti, Federal University of Pernambuco (UFPE - DEE), Recife - Brazil

was born in Recife, Brazil, in 1972. He received the B.S. degree in electrical engineering in 1997 from the Federal University of Pernambuco, Recife, Brazil, and the M.S. and Ph.D. degrees in electrical engineering from the Federal University of Campina Grande, Campina Grande, Brazil, in 1999 and 2003, respectively. He worked as a visiting scholar at Center for Power Electronics Systems, Virginia Polytechnic Institute and State University, Blacksburg - USA, from Oct/2001 to Aug/2002. Since 2003, he has been at the Department of Electrical Engineering, Federal University of Pernambuco, where he is currently a Professor of Electrical Engineering. His research interests are renewable systems and power quality.

Francisco A. S. Neves, Federal University of Pernambuco (UFPE - DEE), Recife - Brazil

was born in Campina Grande, Brazil, in 1963. He received the B.S. and M.Sc. degrees in electrical engineering from the Federal University of Pernambuco, Recife, Brazil, in 1984 and 1992, respectively, and the Ph.D. degree in electrical engineering from the Federal University of Minas Gerais, Belo Horizonte, Brazil, in 1999. He worked as a visiting scholar at Georgia Institute of Technology - USA, during 1999, and at Alcala University - Spain, from Feb/2008 to Jan/2009. Since 1993, he has been with the Department of Electrical Engineering, Federal University of Pernambuco, where he is currently a Professor of Electrical Engineering. His research interests include power electronics, renewable energy systems, power quality and grid synchronization methods.

Pedro Rodriguez, Technical University of Catalonia (UPC), Barcelona - Spain

received the B.S. degree in electrical engineering from the University of Granada, Granada, Spain, in 1989, and the M.S. and Ph.D. degrees in electrical engineering from the Technical University of Catalonia (UPC), Barcelona, Spain, in 1994 and 2004, respectively. He was an Assistant Professor in 1990 and an Associate Professor in 1993 with UPC. He was a Researcher with the Center for Power Electronics Systems, Virginia Polytechnic Institute and State University, Blacksburg, and the Institute of Energy Technology, Aalborg University, Aalborg, Denmark, in 2005 and 2006, respectively. He is currently the Head of the Research Group on renewable electrical energy systems with the Department of Electrical Engineering, UPC. He has coauthored about 100 papers in technical journals and conferences. He is the holder of five patents. His research interests include integration of distributed energy systems, power conditioning, and control of power converters.

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