Banca de DEFESA: VICTOR RAMON FRANÇA BEZERRA DE SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : VICTOR RAMON FRANÇA BEZERRA DE SOUZA
DATE: 21/03/2022
TIME: 14:00
LOCAL: Remota
TITLE:

CONTRIBUTION FOR IMPROVEMENT OF LOW VOLTAGE RIDE THROUGH CAPABILITY ON DOUBLE FED INDUCTION GENERATOR WITH A BACK-TO-BACK MODULAR MULTILEVEL CONVERTER TOPOLOGY

KEY WORDS:

double fed induction generator, multilevel converters, modular multilevel converter, fault current damping, low-voltage ride through.

PAGES: 143
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Sistemas Elétricos de Potência
SPECIALTY: Máquinas Elétricas e Dispositivos de Potência
SUMMARY:

The advancements in power electronics have supported the widespread penetration of wind energy conversion systems (WECS) in electric grids. In this sense, the system based on the Double Fed Induction Generator (DFIG) has a large share of installed wind farms power generation technology, in this configuration the stator is directly connected to the grid and the rotor is interfaced by means of two back-to-back power converters, which have a crucial functionality in the machine control by means of voltages applied to the rotor terminals in order to ensure that the stator voltages and currents have the same frequency as the electrical grid, besides controlling the active and reactive power and are directly related to the harmonic distortion, thermal and mechanical stress levels in the WECS. Currently, several power converters topologies have been employed in order to improve the performance and increase the WECS processed power capability to support the network demand, in this sense, the multi-level converter topologies stand out and can be appropriately used to fulfill these requirements. On the other hand, one of the main features of the DFIG-based WECS is its high sensitivity to electrical disturbances, especially voltage sags, since the stator is directly connected to the grid, this feature highlights a fundamental challenge which is to provide fault support and in particular voltage sags to DFIG. Considering the relevance of this problem, this thesis presents a proposal focused on the improvement of DFIG supportability to a voltage sag in the grid by means of a recent multilevel converter topology, the Modular Multilevel Converter (MMC). The proposal is based on the use of the specific characteristics of the MMC through the presence of internal impedances, in order to provide significant damping of the DFIG transient components of the rotor and stator fault currents during a voltage sag in the grid, effectively contributing to maintaining the DFIG connection, while keeping the controllability and avoiding the protection activation, without the need of structural modifications or additional control loops. Moreover, the proposed structure using the MMC directly contributes to the improvement of the system performance by reducing the harmonic distortion rate and electromagnetic torque oscillation, reducing the heating and internal losses in DFIG windings and increasing the useful life of the gearbox, in addition to providing greater robustness, efficiency and reliability to the set of back-to-back power converters. Results obtained by means of simulations indicate the MMC effective damping capability of DFIG currents and the increase in supportability during a grid fault.

BANKING MEMBERS:
Presidente - 1597497 - LUCIANO SALES BARROS
Interno - 1149567 - ANDRES ORTIZ SALAZAR
Interno - 1807863 - FLAVIO BEZERRA COSTA
Externa à Instituição - YUNTING LIU
Externo à Instituição - FRANCISCO KLEBER DE ARAÚJO LIMA - UFC