Optimal Design Methodology for A High-Frequency Transformer Using Finite Element Analysis and Machine Learning by Eunchong Noh School of Electrical and Computer Engineering University of Seoul February 2022

 Optimal Design Methodology for A High-Frequency Transformer Using Finite Element Analysis and Machine Learning

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science (Electrical and Computer Engineering) December 2021 Thesis committee: Gyu-Sik Kim, Professor, ECE, University of Seoul Seung-Hwan Lee, Associate Professor, ECE. University of Seoul Moon-Que Lee, Professor, ECE, University of Seoul 

 Abstract

 The demand for isolated DC-DC converters is increasing due to the spread of electric vehicles (EV) and the expansion of renewable energy use. Accordingly, the need for a high-frequency transformer, a key component of an isolated DC-DC converter, is also increasing. This trend is also taking place in the field of railway locomotive systems. Solid state transformer (SST) technology to improve the performance and efficiency of railway locomotive propulsion systems is being actively researched, and high-frequency transformer is the core of SST. Highfrequency transformer design for railway locomotive systems has more complex design elements that must be considered for volume-loss optimization and insulation and thermal design. This thesis investigates an optimization design methodology using machine learning and NSGA-II for optimized high-frequency transformer design. For machine learning, Finite-element analysis (FEA) simulation was used to obtain high-frequency transformer parameter data. Conventional high-frequency transformer optimization design methods used analytical models for parameter calculation. However, this analytical model has a significant error when the shape of the high-frequency transformer becomes complicated. In particular, the leakage inductance of the high-frequency transformer is difficult to calculate with an analytical model. So, it is difficult and cumbersome to apply it in the design. This thesis obtained magnetizing inductance, leakage inductance, and copper loss of shell-type transformer models in various shapes using FEA simulation. Then, using the data obtained from the FEA simulation, a machine learning regression model was created to minimize the parameter calculation error in complex shapes. In addition, the NSGA-II algorithm, which is widely used in multi-variable optimization design, is used to find the optimal transformer shape to perform optimization that can satisfy multiple design elements at the same time. Each parameter inferred by the machine learning regression model showed a high correlation and sufficiently low inference error rate, used for parameter calculation in the NSGA-II algorithm. The inferred parameters are used to calculate transformer loss for optimization design or check whether constraints are satisfied. Through the optimization design using NSGA-II, a Pareto front curve for volume and loss that satisfies all design conditions was obtained. The designer can select and use the designs according to the situation. The methodology can be designed for more complex shapes to achieve higherperformance high-frequency transformer design. In addition, the complexity of the design is reduced because numerous consideration factors can be easily considered through constraint setting in the NSGA-II. Finally, unlike the conventional design methodology, which has a significant influence on the skill and intuition of the designer, once the environment is set up, the design proceeds only by inputting target parameters and executing the code so that the design time can be reduced. Therefore, it is possible to design a high-frequency transformer with constantly high performance regardless of the designer's skill level.

VIEW FULL THESIS: https://www.mediafire.com/file/w56it1xqyowh2h8/Optimal+Design+Methodology+for+A+High-FrequencyTransformer+Using+Finite+Element+Analysis+and+Machine+Learning.pdf/file

MODELO DE CÁLCULO DE PERDAS POR COMUTAÇÃO E MÉTODO DE SELEÇÃO DE TECNOLOGIAS DE TRANSISTORES FET APLICADOS A CONVERSORES ESTÁTICOS-Edemar de Oliveira Prado- Dissertação (mestrado) – Universidade Federal de Santa Maria, Centro de Tecnologia, Programa de Pós-Graduação em Engenharia Elétrica, RS, 2020-BRASIL

 ABSTRACT

 SWITCHING LOSSES CALCULATION MODEL AND METHOD FOR SELECTING FET TRANSISTOR TECHNOLOGIES APPLIED TO STATIC CONVERTERS 

Author: Edemar de Oliveira Prado 

Advisor: José Renes Pinheiro 

This dissertation presents an analytical model to assist in the calculation of switching losses and a methodology for selecting MOSFETs that with breakdown voltages greater than 100 V. The model was developed based on physical and electrical concepts of the FET structure, considering non-linearities of Miller capacitance as a function of voltage variation, mainly present in MOSFETs manufactured to operate in voltages above 100 V. Simulation and experimental results that validate the model were obtained, considering the frequency range of 1 - 300 kHz, at which the limit of gate driver operation has been reached. The proposed model was compared to other loss calculation models frequently used in the literature, where it was observed that other models show an increase in the relative error for frequencies above 50 kHz. Heat transfer systems are analyzed and discussed. The proposed loss calculation model is used in the development of a comparative analysis between the technologies of conventional Silicon MOSFET, superjunction, SiC and GaN. The impact of stray capacitances, junction temperature, intrinsic resistances, switching frequency and power levels in each technology are analyzed. Application trend areas are defined for each technology based on yields as a efficiency of frequency and power.

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https://repositorio.ufsm.br/handle/1/22430

Research on the Optimal Design of Weinberg Converter Qian Chen*a, Peng Qiu*,Yi Lu*, Jinpei Du**, Jiayi Wu***, Haihong Yu*, IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING IEEJ Trans 2018

 

Research on the Optimal Design of Weinberg Converter 

AUTHORS:Qian Chen*a, Peng Qiu*, Yi Lu*, Jinpei Du**, Jiayi Wu***, Haihong Yu*,

Because of its advantages of continuous input and output currents, stable transfer function, and high efficiency, the Weinberg converter is used as battery discharge regulator. Its working principle under overlap and nonoverlap modes with stray parameters is analyzed. Then a design method is proposed to optimize the parameters. In order to estimate the heat distribution, the power loss is calculated according to the performance parameters, and then the efficiency trend is achieved toward the output current. In addition, the experimental results verify the optimal design using a 600W prototype. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 1. 

Introduction

 A power conditioning unit (PCU) is comprised of the main error amplifier (MEA), the shunt regulator (SR), the battery charge regulator (BCR), the battery discharge regulator (BDR), and telemetering/telecontrol (TM/TC) [1–5]. PCU balances the energy between each unit to keep the bus voltage constant so that the electrical equipment of satellites can obtain stable power from the main bus. When the satellites cannot get enough energy from the solar battery array in the shadow region or sunshine region, the batteries provide energy for the bus to keep bus voltage constant. BDR plays an important role during this process. Our aim is to study a highpower and high-efficiency boost converter that is easy to expand and realize current-sharing to achieve excellent bus performance. Efficiency, complexity, and linearity play an important role in choosing the topology of the BDR. The normal boost converter is not suitable for BDR because of its low efficiency, instability, and discontinuous output current. So far, the topologies that have been used in BDR are [6–8] phase-shift full bridge (PSFB), Superboost, Smart Add on, HE-Boost, and Weinberg.

VIEW FULL TEXT:https://onlinelibrary.wiley.com/doi/abs/10.1002/tee.22764

Analysis and Design of Multioutput Flyback Converter A study For A Lab Upgrade on the Flyback converter assignment at CHALMERS UNIVERSITY TECHNOLOGY Master's thesis in Electric Power Engineering Abdi Ahmed Abdullahi Kosar

 

Master's thesis 2016:ENM Analysis and Design of Multioutput Flyback Converter A study For A Lab Upgrade on the Flyback converter assignment at Chalmers Elteknik ABDI AHMED ABDULLAHI KOSAR Department of Energy & Environment Division of Electric Power Engineering Chalmers University of Technology Gothenburg, Sweden 2016

Abstract 

This thesis work is done in order to improve the existing lab in Chalmers for the study of Power Electronics. Assignments for the practical lab and computer simulation sessions of a yback converter have been reviewed and analysed. The analyses of the existing assignments shows that the circuit board used in the lab today is a multi purpose circuit and it is dicult to relate a equivalent circuit diagram of a yback converter. Furthermore, there is no relationship between the circuit and the simulation model. A simulation was done using PSpice and a prototype PCB board built with the aim of showing some of these interesting concepts in the course. The main suggestions are related to the simplication of the circuits so that immediate correlation can be made between the circuits being shown in the class and the PCB used in the lab. The simulation model can be used in the simulation session of the course. The new simulation model and the circuit board can demonstrate the role of the inductor in the yback transformer by varying its value. Another area of improvement would be on demonstrating of magnetics theory. There is no simulation or practical assignments about magnetics in the course today. Understanding the relation between the current ripple and magnetic ux is in the scope of the courses. It is also important to understand how high frequency aects the losses and the size of the core. Two transformers are designed in order to investigate these relationships. The result of the transformer design shows that a new assignment that can demonstrate how magnetic core behaves can be introduced.

VIEW FULL TEXT:https://odr.chalmers.se/handle/20.500.12380/252784

Multi Level Inverter System using Dual Output DC-DC Converter with High Gain-Doctoral Dissertation-Department of Electrical Engineering Graduate School, Chonnam National University by Ibadullaev Anvar-February 2021

 

Multi Level Inverter System using Dual Output DC-DC Converter with High Gain Ibadullaev Anvar Department of Electrical Engineering Graduate School Chonnam National University (Supervised by Professor Park SungJun)

 (Abstract) Electricity has a weighty and an important impact on the social, industrial and economic developments of countries around the world because it is an essential ingredient of modern civilization. XXI century civilization depends on constant accessibility of this wealth in order to continue the present form of life and developing. Recently, with the development of green energy producing technology, the use of renewable sources such that photovoltaic arrays(PV), fuel cell sources, etc. have been increasing rapidly. Depending on the new research report published by “Markets and Market“, the inverter market is projected to grow from USD 12.8 billion in 2020 to USD 26.5 billion by 2025. The inverter market is likely to exhibit lucrative growth potential during the forecast period. The growth of the inverter market is expected to be driven by continuosly rising number of industrial and household solar rooftop installations. This exponentially growth of the inverter selling segment can be understood the entering of photovoltaic energy generation plants, HEV(hybrid electric vehicles) and electric vehicles charging stations that has brought new opportunities and challenges in the power electronics industry, especially in terms of the research and development of the main traction three phase AC motor drives. The multilevel inverter structure based topologies gives the OK to these vehicles to hold out to high voltages and power levels without using bulky and hard transformers. And also, the limited installation spaces of the HEVs have also led to the requirement for small size and power efficient inversion devices. Among end users, the residential segment held the largest share of the inverter market in 2019. Continuously rising electricity bills, coupled with supportive government policies worldwide, have led to the increasing adoption of energy conservation measures such as solar rooftop installations for controlling the increased energy expenditure in residential applications. Countries such as Japan, the United States, the Netherlands and Australia which are among the prominent markets for residential rooftop solar installations, have widely adopted solar inverters over conventional non-solar inverters. In addition, countries such as Brazil, the United Kingdom, India and Mexico are currently witnessing significant growth in the residential solar energy market. In modern smart grid solutions, control technologies for the consumption can response based on information about the electricity generation and transmission system and prices in an automatic way to improve the performance and reliability of the system. Demand for better designed hardware topology and controllers is constantly rising as the renewable energy market continues to sharply grow. In a typical residential, or small factory utility photovoltaic arrays are connected in series, in parallel or mixed type to form high DC voltage bus to can connect to DC-AC inverter, which then is connected directly to single or three phase AC Grid. Using renewable power generation systems established with step up dc-dc converters is being popularized because of the rising demand of zero pollution and eco friendly renewable energy sources. In this study, a new constructed multi level inverter system using dual outptut DC–DC converter was proposed to match a low DC voltage output sources, such as photovoltaic source or fuel cell systems with single phase AC grid bus lines. When comparing to other conventional multi level inverters, the proposed multi level inverter has a decreased number of the semiconductors, can create higher quality power with lower THD values, has decreased and balanced voltage stress for dual output dc-dc converter DC capacitors. The proposed topology requires a single DC source.

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http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=7aa262e880813a19ffe0bdc3ef48d419&keyword=inverter

WEBSITE MEDIAFIRE: https://www.mediafire.com/file/lmmi1yh2aafq4t9/MULTILEVEL+INVERTER+SYSTEM+USING+DUAL+OUTPUT+DC-DC.pdf/file