Banca de QUALIFICAÇÃO: CAROLINA ALBUQUERQUE CALDEIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : CAROLINA ALBUQUERQUE CALDEIRA
DATE: 28/02/2023
LOCAL: Departamento de Engenharia Elétrica - Sala 014
TITLE:

DC CONVERTER VOLTAGE BOOST BASED ON A THREE-WINDING COUPLED INDUCTOR .

KEY WORDS:

Grid-connected photovoltaic systems; high gain dc-dc converter; three-winding coupled inductor; shared ground. 

PAGES: 113
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUMMARY:

The increase in world energy demand and the effects of environmental degradation have driven the use of sustainable energy generation alternatives, such as the solar energy source. Most non-isolated photovoltaic systems are connected to the electrical grid, resulting in grounded photovoltaic modules in order to avoid concerns related to the leakage current circulation. However, the voltage levels generated by the solar energy source do not meet the voltage levels required by the d.c.-a.c. converter in order to be connected to the grid. Therefore, the connection between a high voltage gain dc-dc converter and the photovoltaic module is important, in order to extract its maximum power and enable its connection to the grid. The dc-dc converter should also meet the shared ground requirement between the input and output of the photovoltaic system. In this scenario, this thesis project proposes a new high gain dc-dc converter topology to be used in a microinverter or as a solar optimizer in photovoltaic systems connected to the electrical grid with a shared ground feature. The proposed converter integrates the switched capacitor and three-winding coupled inductor high voltage techniques, in addition to a clipping circuit to reduce losses in the main switch and in the output diode. The proposed converter was designed to operate with the input voltage between 29 and 45 V, output voltage of 400 V, switching frequency of 100 kHz, duty cycle between 0.46 and 0.66 and output power of 400 W. In order to understand the operating characteristics of the converter and the system to which it will be applied, its operating stages are presented, as well as its main waveforms, the equations that represent its static analysis in continuous conduction mode, the voltage stresses in semiconductor elements and its design guidelines. Open-loop simulation results in the MATLAB/Simulink environment are also presented and a comparative analysis of the proposed converter with six other recent topologies in the literature, which employ a coupled inductor with three windings in its voltage multiplier cell. From the results, the proposed topology has a high voltage gain for low duty cycles, standing out compared to the others in terms of the low voltage stresses on the output diode and switch, in addition to fewer components and lower cost. 

COMMITTEE MEMBERS:
Presidente - 2921718 - FABRICIO BRADASCHIA
Interno - 2889145 - GUSTAVO MEDEIROS DE SOUZA AZEVEDO
Externo à Instituição - MARCELLO MEZAROBA - UDESC