engKorompili, AsimeniaMonti, AntonelloDragicevic, TomislavTwo-level control for multi-terminal DC distribution gridsinfo:eu-repo/classification/ddc/621.3DC power systemsDC/DC converterscontroloptimisationMulti-terminal DC distribution grids have recently gained research attention, since they offer more efficient and reliable integration of converter-interfaced distributed energy resources (DER) and flexible loads at different locations in the power systems. For the application of active network management (ANM) concepts in MTDC distribution grids, the integrated DER and flexible loads should participate to the system regulation, while preserving the owners' data privacy. Due to fast DC dynamics and the intermittent nature of DER based on renewable energy sources, fast control actions should be performed for MTDC distribution grids. Furthermore, since these distribution grids are emerging, prone to future network expansion and increasing DER integration, the developed control approaches should present plug-and-play capability, modularity and scalability. In addition, they should present tolerance to failures of the control structure that realises them. Literature mostly considers single-bus DC microgrids, which are regulated with an hierarchical control equivalent to this of AC systems. However, this control approach presents limitations regarding the aforementioned desired characteristics of MTDC distribution grids. To overcome the limitations of the existing approaches, this dissertation proposes a two-level control for MTDC distribution grids, consisting of the converter-level controllers that receive set-points from the system-level control. For the converter-level control, the active disturbance rejection control (ADRC) technique is applied as voltage controller in DC/DC converters, which relies on the estimation and rejection of the total disturbance. Two ADRC models are developed, one linear and one non-linear, offering different features to the performance of the converter-level control, stemming from the different integrated estimation and feedback control methods. Both developed ADRC models are designed to be suitable for minimum- and non-minimum-phase class of the DC/DC converters, achieving the desired dynamic performance, without large control input. Moreover, they are designed for effective disturbance rejection, thanks to the application of the concept of the generalised ADRC. Furthermore, they present plug-and-play capability, as they achieve to handle unknown disturbances in different MTDC distribution grids, without any modification in their design. For the system-level control, a fully-distributed OPF-for-ANM algorithm is developed. This integrates various ANM schemes in the OPF problem for the coordination of diverse DER and flexible loads under various power dispatch strategies. The integrated power dispatch strategies consider the technical operational characteristics of the DER and flexible loads at each time period of the system-level control, providing thus feasible voltage and power set-points to the DC/DC converters of the grid. Despite the increase of the problem dimension due to the integration of the ANM schemes, the algorithm achieves fast execution, being thus suitable for the realisation of the system-level control at the time scale of secondary control level. Thanks to the nodal formulation of the OPF-for-ANM problem, the system-level control presents high scalability and modularity. Moreover, the algorithm is suitable for radial or meshed topology of the MTDC distribution grids, as the nodal formulation of the OPF-for-ANM problem does not depend on the network topology. Furthermore, the developed algorithm is tolerant to failures in the communication system of the distributed control structure, thanks to the integration of a strategy for surviving such failures. In this way, the system-level control presents high reliability for providing the set-points to the DC/DC converters of the grid. In addition, the algorithm respects the data privacy of the owners of the power units in the grid, as it does not require the exchange of electrical quantities of individual power units, but only total nodal electrical quantities. This work presents the aforementioned developments, by demonstrating their beneficial features that constitute contributions to the field of control for MTDC distribution grids. Suggestions for further work on various directions, beyond the developments presented here, are also provided.Aachen : E.ON Energy Research Center : ACS, Automation of Complex Power Systems, E.ON Energy Research Center 138, 1 Online-Ressource : Illustrationen (2025). doi:10.18154/RWTH-2025-01987 = Dissertation, RWTH Aachen University, 2024info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionE.ON Energy Research Center : ACS, Automation of Complex Power Systems2025info:eu-repo/semantics/openAccessDEhttps://publications.rwth-aachen.de/record/1005762https://publications.rwth-aachen.de/search?p=id:%22RWTH-2025-01987%22StudentsStudent Financial Aid ProvidersTeachersResearchersinfo:eu-repo/semantics/altIdentifier/doi/10.18154/RWTH-2025-01987info:eu-repo/semantics/altIdentifier/isbn/978-3-948234-52-2