Name: ANDRÉ LUIZ SILVA CRIVELLARI

Publication date: 05/08/2022
Advisor:

Name	Role
MARCIA HELENA MOREIRA PAIVA	Co-advisor *
WALBERMARK MARQUES DOS SANTOS	Advisor *

Examining board:

Name	Role
DOMINGOS SÁVIO LYRIO SIMONETTI	Internal Examiner *
MARCIA HELENA MOREIRA PAIVA	Co advisor *
WALBERMARK MARQUES DOS SANTOS	Advisor *

Summary: In the search for more efficient dc-dc converters, designers seek to use mathematical methods to design them to minimize losses. Scanning and genetic algorithms are the methods used to determine the best operating points in the design of inductors, semiconductor and diode choices, for example. However, a point that does not go through this search is the starting point, that is, the choice of topology. With several available in the literature, it depends on the designer’s knowledge to choose the correct one that will generate better values. Thus, this dissertation is dedicated to working on this first step: to develop a procedure for synthesizing converters and with many generated topologies available, apply a topology evaluation metric to decide on the one that best meets the needs of the designer without having to apply
for all a genetic algorithm to know which would be the most efficient. The work
involved developing a topology generation procedure offering only the maximum number of keys. This synthesis will be done with the application of graph theory, which also provides a simple method to obtain the operating values of the converter elements in each operating interval. As candidate metrics, there are MSEF and processed power, three methods existing in the literature of simplified calculation from the average values of the converter elements or the values of current and voltage oscillation. Such metrics will be investigated by applying them to step-up, step-down and step-down converters, and it will be verified if they can provide a quantitative value that allows classifying the topologies according to which would be the most efficient. Finally, all these steps are summarized in an example of a search for a step-up converter with up to four switches for an input voltage value of 100 V, an output voltage value of 120 V and an output power of 100 W. To confirm the validity of the proposed methods, the topologies found with the best values were simulated in Powersim’s PSIM 2021 software to account for
Keywords: dc-dc converters, synthesis, power electronics, graph theory, state space approach, Fryze method, MSEF.

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