Date and location: April 23 (Thursday), 11am at 45-600B
Speaker: Ivan Petrić, Director of Power Electronics R&D at 1st Avenue Power (1AP)
Abstract: Power systems are undergoing a fundamental transformation, driven by the rapid proliferation of inverter-based resources (IBRs) and the new load trends such as GW-scale data centers. This shift introduces stability challenges unlike those encountered in traditional power systems, with critical dynamics emerging at microsecond-to-millisecond timescales. Enabling large-scale converter-to-grid integration requires a holistic perspective that bridges power systems, power electronics, and control theory. Power electronic converters are the physical links between diverse dynamical systems, and, beyond energy conversion, their information processing capabilities are rapidly increasing. As such, they can assume a key role in actively stabilizing the grid via robust, adaptive, and data-driven control algorithms.
This talk presents impedance-based modeling and passivity theory as a unifying framework for both analyzing stability of IBR-dominated grids and designing converter-level control in pursuit of system-level objectives. The presentation starts with converters operating at the “grid-edge”, whose single-port impedance properties are relevant for the interconnection stability. It is shown how digital control delays introduce negative resistance behavior at high frequencies, where classical active damping techniques are ineffective. Oversampled digital modulation is presented as a solution that inherently extends dissipative behavior to very high frequencies, enabling robust stability. The impedance framework is then extended to interlinking converters operating at the “grid center”, with dynamic uncertainties at all ports. Unterminated MIMO impedances are defined, accounting for port-coupling dynamics. Using an HVDC case study, it is demonstrated that single-port analysis can lead to incorrect stability predictions due to port-level unobservability. Finally, the concept of all-port impedance passivity is introduced and used to develop decentralized stability indicators. In an example scenario, these tools are applied to stabilize an interlinking DC-AC converter, without requiring knowledge of grid impedances.
The talk concludes with a discussion of open challenges and future research directions toward robust integration and stability of increasingly complex, converter-dominated power systems.
Speaker Bio: Ivan Petrić was born in Belgrade, Serbia, in 1994. He received the B.Sc. and M.Sc. degrees in electrical engineering from the University of Belgrade, Serbia, in 2017 and 2018, respectively, and the Ph.D. degree in electrical engineering from the University of Padova, Italy, in 2023. In 2022, he was a Visiting Researcher with the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley. Since 2023, he has been an Affiliate Member of the Department of Electrical, Computer and Energy Engineering at the University of Colorado, Boulder. He is currently the Director of Power Electronics R&D at 1st Avenue Power, a Silicon Valley start-up in clean energy. His research interests include optimization, modeling, and control of power electronic converters, with applications to grid-connected systems, in which he has authored 20 journal publications.