Banca de DEFESA: MARCIO RODRIGO SANTOS DE CARVALHO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARCIO RODRIGO SANTOS DE CARVALHO
DATE: 24/10/2022
TIME: 13:30
LOCAL: Sessão por videoconferência - Link: https://meet.google.com/onk-fisi-mjb
TITLE:

SOFT-SWITCHING HIGH STEP-UP DC-DC CONVERTER BASED ON SWITCHED-CAPACITOR AND MAGNETIC COUPLING VOLTAGE MULTIPLIER CELL FOR PV SYSTEMS.

KEY WORDS:

High step-up dc-dc converter, soft switching, three-winding coupled inductor, voltage multiplier cell.

PAGES: 231
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUMMARY:

The development of technologies to improve the performance of photovoltaic (PV) module integrated converters are fundamental to raise grid-utility distributed generation systems from the photovoltaic solar source in large urban centers, mainly for residential applications with continuous partial shading and complex roof structures with different tilts and orientations. Since both the rated voltage and efficiency of PV modules are very low, high-gain high-efficiency DC-DC converters are required in microinverters and parallel-connected power optimizers to track the maximum available power from a PV module and to boost the DC-link voltage above the minimum value necessary for delivering the generated energy in a 127 V or 220 V single-phase grid. Therefore, this work presents a high step-up voltage multiplier cell (VMC) based DC-DC converter with soft switching operation. The VMC is combined with a switched capacitor and a three winding coupled inductor. The voltage spike on the main switch is reduced and the leakage inductance energy is recycled by an active clamp circuit. The switch in the active clamp circuit provides ZVS condition for the main switch and vice-versa. Thus, the switching losses are negligible and high switching frequency can be used in order to further minimization of passive components size and weight. The secondary winding of the coupled inductor is employed to provide high voltage gain without operating under extreme duty cycle condition, while the tertiary winding is used to establish a DC component in the magnetizing current, which allows decrease of the magnetizing current ripple to meet the ZVS turn-on condition of the main switch. Hence, the core and conduction losses of the coupled inductor, and the conduction and switching losses during the switches turn-off transition can be reduced. The autotransformer leakage inductances are used together with the capacitors to form resonant tanks, causing the current flowing through the diodes to decrease naturally to zero even before they become reverse-biased. Then, ZCS of the diodes is achieved and hence there is no reverse-recovery losses. The operation principle, steady-state analysis, design guidelines and loss analysis of the proposed converter are presented. The proposed converter is compared with two DC-DC converter that combine magnetic coupling and switched-capacitor techniques, and employ two switches as well. Experimental results obtained from 350 W prototype of the proposed converter are presented. The measured maximum efficiency is 96.7%.

COMMITTEE MEMBERS:
Interno - 2921718 - FABRICIO BRADASCHIA
Presidente - 1814693 - LEONARDO RODRIGUES LIMONGI
Interno - 2378833 - MARCELO CABRAL CAVALCANTI
Externo à Instituição - MÁRIO LÚCIO DA SILVA MARTINS - UFSM
Interno - 1543575 - PEDRO ANDRE CARVALHO ROSAS
Externo à Instituição - TELLES BRUNELLI LAZZARIN - UFSC