Les nouvelles stratégies de contrôle d’onduleurs pour un système électrique 100% interfacé par électronique de puissance by Guillaume Denis-

 From grid-following to grid-forming: The new strategy to build 100 % power-electronics interfaced transmission system with enhanced transient behavior Les nouvelles stratégies de contrôle d’onduleurs pour un système électrique 100% interfacé par électronique de puissance 

 Thèse présentée en vue d’obtenir le grade de Docteur En Spécialité: Génie Électrique Par Guillaume Denis Doctorat délivré par Centrale Lille Résumé In the context of renewable energy and HVDC links development in power systems, the present work concerns the technical operations of such systems. As wind power, solar photovoltaics and HVDC links are interfaced to the transmission grid with power-electronics, can the system be operated in the extreme case where the load is fed only through static converters?Driving a power system only based on power electronic interfaced generation is a tremendous change of the power system paradigm that must be clearly understood by transmission grid operators. The traditional “grid-feeding” control strategy of inverters exhibits a stability limit when their proportion becomes too important. The inverter control strategy must be turned into a “parallel grid-forming” strategy.This thesis first analyses the power system needs, proposes the requirements for “parallel grid-forming” converters and describes the associated challenges. Accordingly, the thesis gives a method for designing a stable autonomous synchronization controls so that grid-forming sources can operate in parallel with a good level of reliability. Then, a method is proposed to design a voltage control for a grid-forming PWM source taking into account the limited dynamic of large converters. The robustness of the solution is discussed for different configuration of the grid topology. A current limiting strategy is presented to solve the current sensitivity issue of grid-forming converters, subject to different stressing events of the transmission grid. The ideas developed on a single converter are then applied on small grids with a limited number of converters to allow a physical interpretation on the simulation results.

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