Time-scale dependent modeling and control of LVDC microgrids by Eduardo VASQUEZ MAYEN

In the current evolving distribution grid, microgrids are emerging as valuable tools that can facilitate the integration of renewable energies. In recent years, DC microgrids have garnered interest due to several advantages. These advantages include fewer conversions, the absence of reactive power and frequency, and lower line losses. As a developing technology, many aspects must be studied to facilitate their implementation. This thesis aims to contribute to a better understanding of DC microgrids.

The following work provides an overview of the current state of DC microgrids. Their advantages over AC microgrids are discussed and illustrated. The different topologies and DC bus configurations are described. Potential power quality issues are examined. The current challenges of the technology are explored. Finally, the current state of standardization and existing implementations are detailed.  

This work presents three major contributions. First, an overview and comparison of different control methods for converters in DC microgrids are provided. Both first-level controls and second-level controls are detailed and simulated. The second contribution of this work concerns a power flow algorithm tailored for DC microgrids. This power flow method is adapted for bipolar DC microgrids and further developed as a sequential power flow. This sequential power flow allows the study of the behavior of a DC microgrid over extended periods. The sequential power flow is then used to compare the performance of unipolar and bipolar DC microgrids. The final contribution of this work concerns the modeling of High-Frequency AC link three-port DC/DC/DC converters. The functioning of this type of converter is covered in detail. An averaged model and possible control schemes for this type of converter are proposed.

Jury members :

• Prof. Emmanuel De Jaeger (UCLouvain, Belgium), supervisor
• Prof. Hervé Jeanmart (UCLouvain, Belgium), chairperson
• Prof. Bruno Dehez (UCLouvain, Belgium)
• Prof. Marc Bekemans (UCLouvain, Belgium)
• Dr. Benoît Bidaine (CE+T Power, Belgium)
• Prof. Jan Desmet (University of Ghent, Belgium)

Visio conference link : https://teams.microsoft.com/l/meetup-join/19%3ameeting_YjA3MDllZTYtMjNlNS00Zjk0LWJkNzgtYTk5MGFhZjE4NWM1%40thread.v2/0?context=%7b%22Tid%22%3a%227ab090d4-fa2e-4ecf-bc7c-4127b4d582ec%22%2c%22Oid%22%3a%221b8873ff-fd82-490d-8aad-d7999079673f%22%7d