Banca de QUALIFICAÇÃO: RAFAEL CÂNDIDO GOMES DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RAFAEL CÂNDIDO GOMES DA SILVA
DATE: 07/08/2026
TIME: 09:00
LOCAL: Formato Remoto
TITLE:

Modeling of Electrolytic Capacitors Based on Fractional Order Elements

KEY WORDS:

Fractional Order Calculation, Constant Phase Element (CPE),
Fractional Order Capacitor (FOC), Equivalent Series Resistance (ESR).

PAGES: 53
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Eletrônica Industrial, Sistemas e Controles Eletrônicos
SPECIALTY: Automação Eletrônica de Processos Elétricos e Industriais
SUMMARY:

Power converters are essential for the operation of modern electronic systems, with the DC-Link bus being particularly relevant for signal filtering and stabilization. However, the electrolytic capacitors used in these buses represent one of the most vulnerable points, accounting for up to 30% of converter failures. Condition monitoring (CM) focused on equivalent series resistance (ESR) and capacitance is vital for predictive maintenance, but traditional integer-order models fail to capture the memory, dissipation, and frequency dispersion effects intrinsic to real components. To overcome these limitations, this dissertation proposes the development and validation of a robust method for near-online identification of electrolytic capacitor parameters using Fractional Order Calculus (FOC), representing the component as a Constant Phase Element (CPE) or Fractional Order Capacitor (FOC). The methodology adopts the design of a recursive parallel RC network with compensation elements to approximate fractional behavior. To validate the proposed model, computer simulations and experimental bench tests were performed on a two-stage (Boost and VSI) three-phase photovoltaic (PV) system. Through the injection of harmonic signals in the 2.5 kHz to 5.0 kHz range and the use of the Fast Fourier Transform (FFT), the capacitor parameters were estimated. The experimentally obtained results showed that the average error of the estimated ESR in relation to the FOC model was less than 5%, validating the accuracy, robustness, and applicability of the proposed methodology for improving fault diagnosis systems in power electronics.

COMMITTEE MEMBERS:
Externo à Instituição - ALEXANDRE CUNHA OLIVEIRA - UFCG
Presidente - 1196444 - RICARDO LUCIO DE ARAUJO RIBEIRO
Externo ao Programa - 1168362 - THIAGO DE OLIVEIRA ALVES ROCHA - UFRN