Metodologia de análise de perdas do conversor Flyback utilizando método de elementos finitos e modelos empíricos

Abstract

A search for energy efficiency has been gaining significant attention in various areas. This pursuit reflects the growing awareness of environmental challenges, energy price volatility, and the need to optimize the use of available resources. According to the International Energy Agency (IEA), energy efficiency plays a crucial role in reducing carbon dioxide (CO2) emissions and has become a very attractive market. In light of this, research aims to find new ways to mitigate energy losses, including in energy converters. These devices are present in various aspects of human daily life, such as lighting. These converters experience losses in their components during operation, highlighting the importance of seeking greater efficiency. This work introduces a new methodological approach to estimate losses with greater precision, using empirical models for semiconductor losses and finite element analysis (FEA) for magnetic losses. For semiconductor losses, a PCB was used to conduct tests on devices with a double-pulse test (DPT) circuit, also demonstrating good practices for obtaining high-quality measurements on an oscilloscope. As for FEA, the FEMM software, in conjunction with Matlab, was used to assist in project automation and iterations. This facilitates the simulation of various projects and models the magnetic aspects for harmonics corresponding to 99.9% of the energy. These harmonic frequencies are determined through Fourier Series. To analyze parameter variations, a Monte Carlo Simulation was performed, providing insight into how each project variable (magnetic transformation ratio, MOSFET switching frequency, snubber clamping voltage, core air gap) influences individual component losses and overall efficiency. Finally, the work presents two converter experiments, using the same PCB as in the DPT, to validate the proposed methodology. The converter was powered with 250 V direct current to supply a 50W LED luminaire. The experimental results achieved efficiencies of 93.75% and 90.78%, with a relative percentage error of less than 1% for the converter’s overall efficiency compared to the values estimated by this work.