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- Autorinnen/Autoren:
- Goldhahn, Ulli
- Dokumenttyp:
- Dissertation / Thesis
- Titel:
- Optimale Steuerungsansätze und stabilisierende Regelungsmethoden von einzelnen und zwei gekoppelten MMCs für HVDC-Leistungsübertragungen
- Betreuerin/Betreuer:
- Hillermeier, Claus, Prof. Dr. rer. nat. habil.
- Gutachterin/Gutacher:
- Hillermeier, Claus, Prof. Dr. rer. nat. habil.; Weyh, Thomas, Prof. Dr.-Ing. habil.
- Tag der Abgabe:
- 09.04.2025
- Tag der mündlichen Prüfung:
- 14.10.2025
- Publikationsdatum:
- 25.11.2025
- Jahr:
- 2025
- Umfang (Seiten):
- XII, 227
- Sprache:
- Deutsch
- Schlagwörter:
- Energieübertragung ; Energiespektrum ; Modularer Mehrpunktstromrichter ; Schwingung ; Optimalwertregelung ; Regelungstechnik ; Simulation
- Stichwörter:
- modular multilevel converter, MMC, energy oscillations, feedback control, optimal control, steady state operation
- Abstract:
- For the implementation of the ongoing global energy transition, it is necessary to transport large amounts of electrical energy over long distances and to redistribute it quickly in the event of a fault. The modular multilevel converter (MMC) is particularly suitable for this transmission due to its easily scalable topology, its high output voltage quality and its ability to realize fast voltage changes. For this purpose, modern methods are required for precise control of the MMC through the simultaneous control of the arm currents and the energies stored in the capacitors of each arm, which necessitates relatively large capacitances in the submodules to compensate for energy oscillations during peration. The degrees of freedom of the MMC dynamics are divided into variables that are responsible, on the one hand, for the external DC- and AC-currents as well as for the power flow through the converter and, on the other hand, for the redistribution of energy within the MMC. The latter are referred to as the internal degrees of freedom of the MMC dynamics. In order to reduce the size of the aforementioned cost-intensive capacitances in the submodules, an analytical method was developed in this dissertation to solve a minimization problem while consistently exploiting all internal degrees of freedom (circular currents & common-mode voltage) in the steady state. This leads to a reduction of the oscillation strength of all internal energy components by 75%, compared to the otherwise common freezing of the internal degrees of freedom to zero. Furthermore, two approaches were further developed in this work (basic- and extended-approach) which, in the case of a sudden change in the DC voltage and in the absence of power over a short time interval of less than 10 ms, using all internal degrees of freedom as well as the DC current, ensure a fast and smooth transition from any starting state to a steady-state end condition. Here, the external AC currents remain unchanged during the realized short transition time, while the total energy between the arbitrary starting state and the steady-state end state varies, making it more difficult due to the DC voltage jump. In the extended approach, in comparison to the basic approach, the final state of the 4 internal degrees of freedom is only partially known, due to the partial optimization of the oscillation strength of the internal energy components. Thus, in the end steady-state, in contrast to the basic approach, the amplitude of the circulating current components is initially left free and used to minimize the power oscillations of the internal energy components during the transition interval. After the minimization of the oscillation strength of the arm energies in the steady state and the trajectory design for the transition, which can also be used to compensate for large errors, have been worked out, three different control methods are finally presented. These are based on hierarchically successive steps with different time scales, which were designed to be current-, energy- or lyapunov-based, in order to compensate for both internal deviations due to discretization errors and external deviations in the AC- and DC-voltages. Finally, the gained insights from the minimization of the internal energy oscillations and the control were extended to two MMCs connected by a long HVDC transmission line to an AC-DC-AC transmission system. Their theoretical approaches could be illustrated with simulation results, as with the single MMC.
- DDC-Notation:
- 621.31
- URN:
- urn:nbn:de:bvb:706-001102
- Fakultät:
- Fakultät für Elektrotechnik und Informationstechnik
- Institut:
- EIT 7 - Institut für Elektrische Energiesysteme
- Professorin/Professor:
- Hillermeier, Claus
- Open Access:
- Ja / Yes
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