CHEN Yijing 8/04/15 LSS à 10h30

SUJET : Commande non-linéaire de réseaux électriques multi terminaux à courant continu.

Sous la direction de Mme : Françoise LAMNABHI-LAGARRIGUE
Son directeur de recherches.
(indiquer les noms par ordre alphabétique)
• Dr. Annaswamy ANURADHA
• Dr. Abdelkrim BENCHAIB
• Dr. Gilney DAMM
• Prof. Giri FOUAD
• Prof. Didier GEORGES
• Prof. Alain GLUMINEAU
• Prof. Ricardo MARINO


Nowadays the world total electricity demand increases year by year while the existing alternating current (AC) transmission grids are operated close to their limits. As it is difficult to upgrade the existing AC grids, high voltage direct current (HVDC) is considered as an alternative solution to several related problems such as: the increase of transmission capability; the interconnection of remote and scattered generation from renewable energy sources (in particular offshore); the interconnection of different asynchronous zones.
The research work in this dissertation was started with the intention of filling some gaps between the theory and the practice, in particular: 1) to investigate various control approaches for the purpose of improving the performance of MTDC systems; 2) to establish connections between existing empirical control design and theoretical analysis; 3) to improve the understanding of the multi-time-scale behavior of MTDC systems characterized by the presence of slow and fast transients in response to external disturbances.
The main contributions of this thesis work can be put into three areas, namely nonlinear control design of MTDC systems, analysis of MTDC system's dynamic behaviors and application of MTDC systems for frequency control of AC systems.
In the area of nonlinear control design of MTDC systems, based on different nonlinear control design techniques, new control schemes have been proposed with corresponding theoretical analysis. Besides, the developed control algorithms have been tested by numerical simulations, whose performances are evaluated in comparison to the performance of the conventional vector control method.
The contribution in the area of analyzing MTDC system's dynamic behaviors consists of three parts:
1) control induced time-scale separation for a class of nonlinear systems;
2) analysis of time-scale separation for an MTDC system with master-slave control configuration;
3) analysis of time-scale separation for an MTDC system with droop control configuration.
Theoretical analysis mainly based on singular perturbation and Lyapunov theories, have been carried out for each of the aforementioned aspects and confirmed by various simulation studies.
The final contribution relates to the application of MTDC systems where frequency support strategy using MTDC systems has been introduced and analyzed.
The principle of the frequency control is to regulate the AC frequency by modulating each AC grid's scheduled (or prescribed) active power.
A DC-voltage-based control scheme for the AC frequency regulation is proposed, which achieves the objective of sharing primary reserves between different AC areas interconnected via an MTDC system without using remote information communication.