Tuesday June 27. Presented by Antonello Monti and Antonino Riccobono.
Modern Power Systems are experiencing profound changes. These are due, on the one hand, to the deeper penetration of grid-connected power electronics converters mainly for the integration of Renewable Energy Sources into the power system, and, on the other hand, to the fact that interaction with other energy carriers becomes more and more frequent. Moreover, many Distribution System Operators (DSOs) are investigating the smart grid concept where ICT solutions are deployed for advanced energy services. Given the growing complexity of Modern Power Systems, the safe and reliable operation of these power systems become a major challenge for both power electronic engineers and power systems engineers as well as mechanical engineers and ICT experts.
In these regards, traditional design and testing methods may fail because pilot projects, even though they may contribute to the solution, are limited in many aspects, such as 1) lack of controllability of many parameters, 2) lack of possibility to perfectly replicate a scenario, 3) the time horizon may be too long, and 4) lack of possibility to export all the elements to new regions. Therefore, new paradigms are needed to overcome the abovementioned design limitations.
Simulation fills this gap, but it must be combined with incremental prototyping. This can be achieved by (Controller) Hardware in the Loop (HiL) and Power Hardware in the Loop (PHiL) technologies which allow physical devices being tested in the complexity of the environment in which they will operate.
This tutorial presents both the HiL and PHiL technologies that support R&D in Modern Power Systems. First, concepts of HiL and PHiL are reviewed and related challenges are presented. Then, a few selected HiL and PHiL real-time setups currently running at the Institute for Complex Power Systems – E.ON Energy Research Center – RWTH Aachen University, Germany, are described.
Univ. Prof. Dr.-Ing. Antonello Monti, since October 2008 Professor for Automation of Complex Power Systems at the faculty for Electrical Engineering and Information Technology at RWTH Aachen.
Before joining RWTH in Aachen, Prof. Monti was Professor of Electrical Engineering at the University of South Carolina (USA). During his tenure at USC he has been Associate Director of the Virtual Test Bed (VTB) project, which focuses on computational simulation and visualization of modern power distribution systems that fully integrate power electronics into the network design. He has developed the real-time extension of VTB for Hardware in the Loop applications and has designed innovative tools supporting the automatic generation of VTB native models. He worked on expanding the limits of real-time simulation thanks to the application of PC clusters and FPGA technology. Prof. Monti was also the director of the Real Time and Electromechanics Laboratory (REM Lab) Education.
He started his academic career at Politecnico di Milano after 4 years of industrial experience in Ansaldo Industria.
Antonino Riccobono received the B.S. and M.S. degrees in Electronic Engineering from University of Palermo, Palermo, Italy, in 2006 and 2009, respectively. He received the Ph.D. degree in Electrical Engineering from the University of South Carolina, USA, in August 2013. Since September 2013, he has been working as a Postdoctoral Research Associate at the Institute for Automation of Complex Power Systems (ACS) – E.ON Energy Research Center – RWTH Aachen University, Germany. Within ACS he also covers the charges of Leader of the Team Real Time Simulation and Hardware in the Loop, Lab Manager, and Instructor of the class Power Systems Dynamics.
His research interests have always been in the area of power-electronics-based power systems. These, in particular, include modeling, control, stability analysis, and automation of such systems, linear and nonlinear control systems, grid-connected converter applications, microgrids and nanogrids, hardware in the loop and power hardware in the loop real time simulations.
He has also several years of practical experience in prototyping of Power Electronics converters up to a few kW power level.
Practical Feedback-loop Design of Bus Converters Supplying Regulated Voltage to DC-Input-Port Converters
Tuesday June 27. Presented by Marina Sanz. Download summary (pdf)
In recent years, traditional power distribution systems, based on a centralized architecture, have been progressively replaced by distributed power systems in many applications such as telecommunications, More-Electric Aircraft or microgrids. Distributed architectures offer different advantages such as the use of standardized converters (commercial off-the-shelf, COTS), the easy addition of redundancy, the capability of on-line replacement (hot-swapping) of damaged converters. However, new challenges must be addressed, since the active nature of power electronic converters results in complex dynamic behavior when they are interconnected to each other.
Regarding the proper power system integration, one important issue is the suitable design of the control loop of the Bus converter that should supply the regulated DC voltage to the converters connected downstream. From the point of view of the control design, the small-signal stability of the system must be complied as necessary condition. Hence, the closed-loop input impedance of the load converters must be determined in order to design the feedback-loop of the Bus converter for small-signal system stability. On one hand, sometimes, analytical techniques for closed-loop input impedance calculation require complex derivations. Moreover, this approach is not suitable in case of using commercial converters since internal parameters of the converters are unknown due to the manufacturer´s confidentiality. On the other hand, behavioral modeling techniques allow obtaining the required information of the converters input impedance avoiding the datasheet limitation. Nevertheless, they are difficult, expensive and time consuming since complex measurements, using high-cost instrumentation, plus powerful but complicated identification techniques should be used. Hence, a new approach is proposed in the tutorial trying to overcome these limitations.
The purpose of this tutorial is to review the different state-of-art approaches for deriving the closed-loop input impedance of load converters. To overcome their limitations, a new proposal to calculate the closed-loop input impedance that will be helpful for practicing power system engineers is provided. Finally, automatic regulator design by means of a CAD tool will be also described.
Marina Sanz received the M. Sc. and Ph. D. degree in Electrical Engineering from Polytechnique University of Madrid, Spain, in 1997 and 2004, respectively, where she was a researcher from 1997 to 2001. In 2001 she joined the Department of Electronic Technology at the Carlos III University of Madrid, Spain, where she is currently Associate Professor, Vice Dean of the Engineering School and Head of Electrical Engineering and Automation Bachelor degree.
Prof. Sanz has been involved in Power Electronics since 1997, participating in more than 45 research projects with public and private funding. Her main research interests include power electronics system modelling and stability issues, especially in transport and telecommunication applications. Her research also covers digital control in power electronics and educational issues on power electronics.
Dr. Sanz has published more than 80 papers, many of them in IEEE journals, books and conferences with high impact factor, being one of her research papers awarded with the “Fast Breaking Paper in the Field of Engineering” in 2008. Her research also resulted in 5 patents and an international registered software.
Tuesday June 27. Presented by Rolando Burgos.
The increasing high penetration of power electronics in electrical systems, whether in standalone applications like transportation, or in distribution systems connected to the grid–a result of the massive deployment of renewable energy sources over the past years, has made apparent the need to understand the different types of dynamic interactions that can be induced by them in such systems. Accordingly, this seminar will focus on the dynamic stability assessment of AC systems, using the synchronous d-q frame impedance based analysis to do so. It will present the underlying theory governing the multiple possible interactions, featuring practical examples triggered by constant power loads, and also by grid-tied inverters injecting active power into the grid. A revision of newly developed d-q frame impedance measurement units (IMU) will be presented too.
Rolando Burgos (S’96–M’03) received the B.S. degree in electronics engineering, the Electronics Engineering Professional degree, and the M.S. and Ph.D. degrees in electrical engineering from the University of Concepcion, Concepción, Chile, in 1995, 1997, ´ 1999, and 2002, respectively. In 2002, he joined, as a Postdoctoral Fellow, the Center for Power Electronics Systems (CPES), Virginia Tech, Blacksburg, VA, USA, and become a Research Scientist in 2003 and Research Assistant Professor in 2005. In 2009, he joined ABB Corporate Research, Raleigh, NC, USA, as a Scientist, become Principal Scientist in 2010. In 2010, he joined, as an Adjunct Associate Professor, the Electrical and Computer Engineering Department, North Carolina State University, Raleigh, working at the Future Renewable Electric Energy Delivery and Management Systems Center. In 2012, he returned to Virginia Tech, where he is currently an Associate Professor in the Bradley Department of Electrical and Computer Engineering and CPES faculty. His research interests include multiphase multilevel power conversion, grid power electronics systems, stability of ac and dc power systems, high power density power electronics, modeling, and control theory and applications. Dr. Burgos is Member of the IEEE Power Electronics Society, where he currently serves as Associate Editor of the IEEE TRANSACTIONS ON POWER ELECTRONICS, the IEEE POWER ELECTRONICS LETTERS, and the IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS. He is also the Vice-Chair of the Power and Control Core Technologies Committee of the Power Electronics Society. He is also a member of the IEEE Industry Applications Society and of the IEEE Industrial Electronics Society.