Faculty of Engineering, LTH

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Mini-Workshop at the Department of Automatic Control


From: 2022-01-27 15:15 to 17:00
Place: KC:F and Zoom:
Contact: emma [dot] tegling [at] control [dot] lth [dot] se
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For this mini-workshop the Department of Automatic Control has invited 3 guests, Ioannis Lestas, Matin Jafarian, and Mahdieh Sadabadi to give talks about their research.The gueasts are committee members for Taouba's PhD defence.

Seminar 1
15:20 - 15:50, Ioannis Lestas: Non-expansive semiflows, saddle-point dynamics, and necessary and sufficient conditions for convergence

Finding the saddle point of a concave-convex function is a problem that has been widely studied in since the 1950s in diverse areas and forms the basis of many classes of distributed optimization algorithms. Nevertheless, in broad classes of problems there are features that render the analysis of the asymptotic behaviour of saddle-point dynamics nontrivial. In particular, even though for a strictly concave-convex function convergence to a saddle-point via gradient dynamics is ensured, when this strictness is lacking, convergence is not guaranteed and oscillatory solutions can occur. Furthermore, when the subgradient method is used to restrict the dynamics in a convex domain, the dynamics become non-smooth in continuous time, thus increasing significantly the complexity in the analysis.

Seminar 2
15:50 - 16:20, Matin Jafarian: Stochastic stability of phase-coupled oscillators in uncertain networks

Abstract: Oscillatory behavior is a fundamental feature of complex networks in a wide range of applications including neuronal networks. Phase models have been employed to study synchronization in such networks. This talks presents recent results on the stochastic relative-phase stability of discrete-time phase-coupled oscillators in networks subject to both multiplicative and additive stochastic  uncertainties. In particular, we discuss the impact of the size and sign of the mean-values of  uncertain networks' parameters on achieving the relative-phase stability.

Seminar 3
16:30-17:00, Mahdieh Sadabadi: Cybersecurity in Power-electronics-dominated Power Grids 

Abstract: A reliable electrical power grid is the lifeblood of the economy and essential to every part of society, from manufacturing and internet banking to transportation systems and hospitals. Microgrids play a valuable role in energy systems not only due to their alignment with green growth and smart grid ambitions, but also due to protecting power systems from potential grid interruption such as voltage sag and blackouts. Microgrid technology is becoming ever more reliant on reliable data sharing and information exchange in microgrid control and communication systems, as well as acquiring accurate and fine-grained measurements of power demands. With this high involvement of data, the cybersecurity of microgrids is becoming a major challenge. This talk focuses on issues related to resilience and cybersecurity in power-electronics-dominated DC microgrids. A particular emphasis is on how to deal with such issues from a control perspective and how to design resilient distributed control systems for DC microgrids.