Costa, Flávio BezerraTaveiros, Filipe Emanuel Vieira2018-10-312018-10-312018-08-24TAVEIROS, Filipe Emanuel Vieira. Uma nova estrutura de controle para melhorar a integração do Sistema de Conversão de Energia Eólica baseado no DFIG à rede elétrica. 2018. 214f. Tese (Doutorado em Engenharia Elétrica e de Computação) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2018.https://repositorio.ufrn.br/jspui/handle/123456789/26078The doubly fed induction generator (DFIG)-based wind energy conversion system (WECS) currently leads the wind energy market due to its advantages in comparison to other topologies. The appropriate control of the back-to-back power converter scheme allows the wind turbines based on the DFIG to operate in variable speed mode, whose benefits include maximum extraction of the power available in the wind, reactive power injection and mechanical stress reduction. The increasing number of wind energy conversion systems has led the grid operators to develop specific regulations regarding the connection of these systems to the grid. Under these regulations, the fault ride-through and low voltage tolerance are amongst the most important and relevant aspects, as well as to provide reactive power to the grid in order to restore the voltage level during a fault. Therefore, such systems must maintain a high level of controllability during grid disturbances. This thesis investigates the impact of control and drive strategies on the performance of the DFIG-based wind energy conversion system, under the perspectives of maximum power extraction and fault ride-through, according to the grid regulations of Brazil, Canada, the United States and Germany. It is proposed a new heightened state-feedback control structure with predictive behavior to be applied to the generator control, which considers in an integrated manner the dynamics of the machine currents in conjunction with the general modelling of the electromagnetic disturbance present during symmetric and asymmetric faults, as well as the tracking errors. The proposed structure was designed to effectively suppress the oscillatory dynamics present in the back electromotive force that occurs in the case of a grid voltage disturbance, in order to mitigate oscillations and surges in the electromagnetic torque and the machine currents, exempting the need to use current reference modification strategies or the activation of physical protection during intermediate level faults, thus allowing the DFIG to ride-through symmetrical and asymmetrical disturbances in the grid featuring limited torque oscillations and contributing reactive current, as required by grid codes. In the severe fault case, the proposed structure allows effective tracking of the current references calculated in order to mitigate the oscillations, overcurrent and overvoltage developments. The proposed structure also employs a novel flux damping technique which accentuates the rotor current direct axis component in order to significantly reduce stator flux settling time after faults, while the torque minimally oscillates during post-fault recovery. Results obtained by means of real-time digital simulations and experimental tests under ideal and non-ideal conditions demonstrate the superiority of the proposed structure in comparison to conventional and previous techniques.Acesso AbertoGerador de indução duplamente alimentadoRealimentação de estadosCódigos de redeSuportabilidade a faltas e afundamentosAmortecimento de fluxodoctoralThesisCNPQ::ENGENHARIAS::ENGENHARIA ELETRICA