CAP Seminar Series


roysmithTitle: Stochasticity in feedback loops; Great expectations and guaranteed ruin

Speaker: Roy S. Smith, ETH Zurich

Venue: EEE 1109B

Date and Time: Thursday 06 February 2020, 11:00-12:00

Abstract: Stochastic feedback systems give rise to a variety of notions of stability: median, mean, and variance stability conditions differ. These conditions can be stated explicitly for scalar discrete-time systems with (almost) arbitrary distributions of the stochastic feedback gain. The state variable in such systems evolves towards a heavy-tailed distribution and exhibits some non-intuitive characteristics. For example, one can use stochastic feedback to stabilise unstable systems where one does not even know the sign of the unstable pole or the sign of the system gain. A more dramatic example is an investment scheme which simultaneously yields unbounded expected profit and almost certain bankruptcy to every investor.

Biography: Roy Smith is a Professor in the Automatic Control Laboratory at the Swiss Federal Institute of Technology (ETH, Zurich) in Switzerland. From 1990 to 2010 he was on the faculty of the Electrical Engineering Dept. at the University of California, Santa Barbara. He received his undergraduate education at Canterbury University in New Zealand (1980) and a Ph.D. from the California Institute of Technology (1990).

Roy Smith’s research interests include: the identification and control of uncertain systems, and distributed estimation, communication and control systems. His application experience includes: process control, automotive engines, flexible space structures, aeromanoeuvring Mars entry vehicles, formation flying of spacecraft, magnetically levitated bearings, high energy accelerator control, airborne wind energy and energy control for buildings. He has been a long time consultant to the NASA Jet Propulsion Laboratory on guidance, navigation and control aspects of interplanetary and deep space science spacecraft. He is a Fellow of the IEEE & IFAC, an Associate Fellow of the AIAA, and a member of SIAM and NZAC.

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TodeschiniTitle: Power Quality in Modern Electricity Systems with Large Penetration of Power Electronics-Based Devices

Speaker: Dr Grazia Todeschini, Swansea University, College of Engineering

Venue: EEE 1109B

Date and Time: Wednesday 19 February 2020, 15:00-16:00

Abstract: A power quality disturbance consists in a deviation from the ideal voltage or current waveform, magnitude or frequency. The first power quality problems can be traced back to the invention of electric power, and they have been mitigated with the development of appropriate standards and evolution of design practices. In the last decade there has been a renewed interest in this topic, due to the changing nature of electric loads and generating sources, which cause new power quality concerns. For example, the installation of a large number of PV panels on the distribution system contributes to increasing voltage levels, which may cause damage or malfunctioning to already existing equipment or to protective devices. The first part of this seminar will provide an introduction to power quality concerns, by reviewing definitions, standards, sources of power quality problems, and available mitigating solutions. In the second part, an overview of ongoing research projects in this area will be provided. The main topics addressed are: modelling of power electronics converters for harmonic assessment, harmonic mitigation, deep learning applied to power quality analytics, power quality in dc microgrids and impact of different renewable resources on power quality.

Biography: Grazia Todeschini received her BSc and MSc in Electrical Engineering from the Politecnico di Milano, Italy, and her PhD in Electrical and Computer Engineering from Worcester Polytechnic Institute, in Massachusetts. She was senior consultant with EnerNex, in Knoxville, from 2010 to 2013, and senior power studies engineer with General Electric in Philadelphia, from 2013 to 2016. She became senior lecturer at Swansea University, UK in 2016. Her research interests include power quality, renewable energies integration, power system analysis and the development of power electronics algorithms for power systems applications. She is an IEEE Senior Member and a Fellow of the Higher Education Academy.

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Past talks of CAP Seminar Series