Prof. Marcio Stefanello, Dr.
Prof. Humberto Pinheiro, Ph.D.
Federal University of Santa Maria, Brazil
Prof. Fernanda Carnielutti, Dr.
Federal University of Santa Maria, Brazil.
Prof. Alexandre T. Pereira, M.Sc.
Instituto Federal Sul-rio-grandense, Brazil.
Test-Driven Design of Controllers for Grid-Forming Inverters
Distributed energy resources such as PV, WECS, and BESS, connected to the grid through static converters, are being deployed in large numbers. When a part of the electric grid operates in the island mode, isolated from the main transmission system, the local dispatchable energy resources must adequately share the load demand. This is usually done hierarchically in three levels that are: primary, secondary, and tertiary control. The primary control addresses the control of voltage and the frequency and the active and reactive power sharing among the DER often using only local measurements. This tutorial initially compares two inner loop controllers and virtual inductor implementation alternatives aiming to highlight their strong and weak points in terms of small signal stability and large disturbances resulting, for instance, from short-circuits at the grid side. In addition, a test-driven design will be presented making it possible to benchmark some of the main types of inverter-based DER primary controllers that are: (i) droop; (ii) virtual synchronous generator; and (iii) dispatchable virtual oscillator. A detailed description and a design procedure for the three considered primary and inner loop controllers, followed by an automated HIL test will be given in this tutorial. The HIL test covers a wide range of operating conditions, including steady-state with linear and nonlinear loads, as well as transients such as the one resulting from short-circuit at the load side.
Dr. Stefanello received the M.Sc. and Ph.D. degrees in Electrical Engineering from the Federal University of Santa Maria, Santa Maria, Brazil, in 2006 and 2010, respectively. Since 2010, he has been with the Federal University of Pampa (UNIPAMPA), Alegrete, Brazil, as a professor and is the head of the Energy Processing and Control Laboratory (LAPEC). From 2016 to 2017 he was with the Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, USA, as a visiting scholar. His current research focuses on advanced control techniques for the control of power converters in microgrid applications.
Dr. Pinheiro received the B.S. degree from the Federal University of Santa Maria (UFSM), Santa Maria, Brazil, in 1983, the M.Eng. degree from the Federal University of Santa Catarina, Florianópolis, Brazil, in 1987, and the Ph.D. degree from Concordia University, Montreal, QC, Canada, in 1999. Today, he is a Full Professor at UFSM. His research interests include modulation and control of static converters, especially those used to connect DER to the electric grid. Dr. Pinheiro has more than eighty journal papers and has supervised more than ten Ph.D. students. Dr. Pinheiro is a member of the IEEE Power Electronics and IEEE Industrial Electronics Societies.
Dr. Carnielutti received the B.Sc, M.Sc and the Dr. degrees from the Federal University of Santa Maria (UFSM), Santa Maria, Brazil, in 2010, 2012, and 2015, respectively, all in Electric Engineering. She was Professor with the UFSM—Campus Cachoeira do Sul, Santa Maria, Brazil, from 2016 to 2018. Currently, she is Professor with UFSM— Campus Santa Maria, Brazil, and a Researcher at the Power Electronics and Control Research Group (GEPOC), UFSM. Her research interests include modulation of static power converters, multilevel converters, power electronics for renewable energies and Model Predictive Control. Dr. Carnielutti is a member of the IEEE Power Electronics, Industrial Electronics, and Industry Application Societies
Ms. Pereira received the B.Sc. and M.Sc. degrees in electrical engineering from the Federal University of Santa Maria (UFSM), Santa Maria, Brazil, in 2006 and 2013, respectively. He is currently a Professor in Instituto Federal Sul-rio-grandense (IFSUL). His research interests include modeling and control of static power converters, digital control techniques for power electronics, and the control of grid-connected converters for distributed generation and renewable energy systems and microgrids.