PhD defence by Shih-Feng Chou
01.11.2021 kl. 16.00 - 19.00
Shih-Feng Chou, AAU Energy, will defend the thesis "Modeling of Large-scale Power Electronics Based Power System"
Modeling of Large-scale Power Electronics Based Power System
Professor Frede Blaabjerg
Professor Xiongfei Wang
Associate Professor Pooya Davari
Associate Professor Amjad Anvari-Moghaddam, Aalborg University, Denmark (Chairman)
Dr. Jan R. Svensson, Hitachi Energy, Sweden
Professor Juri Jatskevich, University of British Columbia, Canada
In modern power systems, the increase in renewable energy resources enables power system to replace carbon-intensive energy resources, which can significantly reduce carbon dioxide emission and fight against climate change. Among various renewable energy resources, solar and wind energies have dominated the growth of renewable energy for 20 years, and they still maintain the momentum of growth, which are expected to be even more dominant. Whether it is solar PV generation or wind power generation, these two kinds of renewable energy resources often require power converters interface to connect to the power grid. Due to the demand for power electronic-interfaced renewable energy resources steadily grows, the penetration level of power electronics in modern power systems increases constantly. Since the control dynamics of power electronic converters are multi-time-scale, the interactions between power electronic converters can introduce not only high-frequency voltage and current harmonics into the grid, but also the oscillations in a wide frequency range, which may cause power quality and system stability challenges.
Therefore, to achieve a successful transition to a power electronics-based power system, small-signal modeling methods capable of describing the interactions between adjacent multiple converters in large-scale converter-based power system should be developed. For the system-level stability analysis in power electronic based power systems, it is now achieved by using the aggregated models and reduced-order models developed for synchronous generator based power system in the meantime. Thus, the power-electronic-focused aggregated models are required to evaluate the system stability in a large-scale converter-based power system.
To tackle these issues, this Ph.D. project proposes a small-signal modeling method and stability criterion for single converter and multi-converter systems, which are verified through experimental tests. To further investigate how the parameters in converters affect the oscillations in the system caused by the control dynamics of converters, this Ph.D. project proposes an improved sensitivity analysis method, which can be used to enhance system damping. By employing the presented models, an aggregated model considering the modularity, scalability, and flexibility can be derived. Accordingly, an workflow for modeling and analyzing large-scale power electronics based power system is summarized, where the presented workflow may be used in future power electronics-based power systems to increase the power system reliability.