The Operation and Maintenance Model for Cost Estimation of an Offshore Wind Farm-BY Jae-Hee Park-A THESIS FOR THE DEGREE OF MASTER OF ENGINEERING -JEJU NATIONAL UNIVERSITY

The Operation and Maintenance Model for Cost Estimation of an Offshore Wind Farm

GRADUATE SCHOOL JEJU NATIONAL UNIVERSITY Jae-Hee Park

A THESIS FOR THE DEGREE OF MASTER OF ENGINEERING

Abstract

Several European countries have defined targets to install and to operate offshore wind energy and according to these targets more than 40 GW offshore wind power is expected for the year 2020. Republic of Korea has also defined targets to install and operate offshore wind energy as part of its renewable energy goals. According to its targets, more than 2.5 GW offshore wind power is expected to be installed across Jeju island region and the west side of mainland by the year 2020. So the required effort for operation and maintenance of offshore wind farms will be enormous, also a thorough and appropriate plan of maintenance during the lifetime of these offshore wind turbines is essential for an economical exploitation. The aim of this thesis is to develop operation and maintenance model for an offshore wind farm in Rep. of Korea considering regional marine situation. The model should include both preventive and corrective maintenance plans which needs basic concept of wind energy, wind turbine, and maintenance strategies. The model should be based on real time metrological data, geographic data, generic wind turbine data, equipment data, spare parts and repair data. A 10 minute time series of wind speed data in public water surfaces of Daejeong-eup and 1 hourly time series of Marado significant wave height data in 2010 are used for metrological data. Equipment data is based on vessels of the operating offshore wind farm in the North Sea. Spare parts are modeled from commercial wind turbine components contribution and costs. To define repair data, there are various categories and step to determine the sequence of maintenance phases, and the corresponding amount of work, required equipment and time to organize an each maintenance phase. The operation and maintenance costs are estimated for one year in order to verify the model. A plan of operation and maintenance is set up for offshore wind farm in Jeju Island, Rep. of Korea. The results show that availability of Jeju wind farm is around 90 %. The sum of revenue losses and the total costs of repair is estimated to be approximately 27 % of generation cost which includes 11 % of the total generation cost due to limited equipment usage and 9 % of the total generation cost due to revenue losses for one year in the offshore wind farm. The proposed model can be used for the analysis of different aspects that include overall contributions and costs of operation and maintenance and to make an operation and maintenance support organization and plan for offshore wind farm in Rep. of Korea.

LINK:http://www.mediafire.com/file/7sxzk17rt7yfj04/The_Operation_and_Maintenance_Model_for_Cost_Estimation_of_an_Offshore_Wind_Farm.pdf/file

RELIABILITY AND AVAILABILITY ANALYSIS OF UNINTERRUPTIBLE POWER SUPPLY (UPS) SYSTEM CONFIGURATIONS

RELIABILITY AND AVAILABILITY ANALYSIS OF

UNINTERRUPTIBLE POWER SUPPLY (UPS)

SYSTEM CONFIGURATIONS

A DISSERTATION

SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE

AWARD OF THE DEGREE OF MASTER OF TECHNOLOGY

IN ELECTRICAL ENGINEERING (CONTROL SYSTEM)

BY:

DEEPAK SHARMA

NATIONAL INSTITUTE OF TECHNOLOGY KURUKSHETRA

There are many configurations of UPS. The configurations which are considered for estimating and analyzing the reliability, its parameter and availability in this dissertation work are classified into two groups i.e. Group I and Group II which are as follow

Group I

1. Online UPS with Bypass

2. Online UPS without Bypass

3. Offline UPS

4. Line-Interactive UPS (Buck/Boost)

5. Line-Interactive UPS (Ferroresonant)

Group II

1. Capacity (N) System

2. Isolated Redundant System

3. Parallel Redundant (N+1) System

4. Distributed Redundant System

5. System Plus System "2(N+1)" Redundant System

 

Análise experimental da qualidade da energia de uma microrrede fotovoltaica com back-up Becker, Luís Rodrigo-PROGRAMA PÓS-GRADUAÇÃO EM ENGENHARIA MECANICA-UNISINOS

Análise experimental da qualidade da energia de uma microrrede fotovoltaica com back-up Luís Rodrigo Becker-PROGRAMA PÓS-GRADUAÇÃO EM ENGENHARIA MECANICA-UNISINOS

Dissertação de Mestrado-UNIVERSIDADE DO VALE DO RIO DOS SINOS

Orientador: Dias, João Batista

Resumo:

Este trabalho apresenta uma análise experimental de uma microrrede fotovoltaica formada por dois subsistemas, um isolado com estocagem e outro conectado à rede. Foi verificado o seu comportamento, sua capacidade no fornecimento de energia para uma carga isolada e rede da concessionária, monitorado a qualidade da energia elétrica entregue à diferentes cargas e rede da concessionária e também quantificado os índices de performance do sistema conectado. O subsistema conectado à rede (SFCR) é formado por um painel de 1080 Wp de silício multicristalino e um inversor c.c./c.a. de 1200 W. O subsistema isolado de back-up (SFI-b) é formado por um painel de 600 Wp de silício monocristalino, controlador de carga, banco de estocagem com baterias chumbo-ácido 24 V / 210 Ah e um inversor off-grid c.c./c.a. de 1000 W. O comportamento e a capacidade do sistema são monitorados durante o atendimento de uma carga, representada por um refrigerador. A qualidade da energia é analisada através de medições de energia ativa, reativa e aparente, fator de potência e geração de correntes harmônicas pelos inversores. O SFI-b é monitorado atendendo diferentes tipos e regimes de cargas. Já o SFCR é monitorado em dias de céu claro, parcialmente encobertos e encobertos. Os índices de performance são calculados em dias de céu claro e parcialmente encoberto ao longo dos seis primeiros meses de 2016. Os resultados demonstram que o SFI-b é capaz de atender a carga de forma confiável, comutando-a automaticamente para a concessionária quando o banco de baterias atinge uma profundidade de descarga pré-definida, enquanto o SFCR injeta a energia produzida na rede da concessionária. Os indicadores de qualidade da energia do inversor do SFI-b mostraram-se adequados, permanecendo dentro dos limites citados na legislação e análogos aos apresentados pela rede da distribuidora local. Já o inversor do SFCR apresentou indicadores de qualidade de energia satisfatórios, também na maior parte do tempo dentro dos limites citados na legislação, exceto nos dias encobertos e períodos de baixa irradiância, constatando-se significativa geração de energia reativa e distorções harmônicas de corrente. Considerando a média entre dias de céu claro e parcialmente encoberto, a eficiência média global do SFCR é de 9,9% e a energia média diária entregue à rede é de 4,7 kWh. Foi verificado que a qualidade da energia produzida pelo SFI-b praticamente independe da irradiância, já o SFCR depende diretamente da irradiância e do nível de carregamento do inversor, na geração de uma energia de qualidade.

LINK NA WEB: http://www.repositorio.jesuita.org.br/handle/UNISINOS/6430

Design and Development of an X-Ray Machine Francisco Piernas Díaz-UNIVERSIDAD DE GRANADA-2019

1 Introduction

The X-Ray analysis has developed constantly over time since Wilhelm R¨ontgen discovered it’s applications. X-Rays are now used not only for simple radiography. Modern algorithms are capable of reconstruct a three dimensional view of the object, allowing us to recover important information about the inside of the object to study, for example, a human body. Ionizing radiations like X-Rays have also been used to discover the structure of the DNA thanks to X-Ray diffractometry. This project aims to explore the technologies of 2D radiography (sections 10 and 11) and 3D tomographic scans (section 12), and for that, a 3D printable machine is designed, built and tested using a long list of software, tools and parts [28]. One of these parts is an improved Zero Voltage Switching (ZVS) Mazzilli driver, optimized for higher frequency (section 2.1.3). The design and testing is done considering safety, as described in section 9. A Geiger counter is used to ensure that the device is safe to operate and that the operator is not exposed. In addition to the device, three programs written in C++ have been developed. The first one is an original implementation of the inverse Radon transform to perform tomographic reconstructions of the data gathered wih the X-Ray machine and it’s explained in appendix A. The second program, found in appendix B, uses an original algorithm for pseudocolor radiography that tries to improve other algorithms that usually saturates the color of the result. The last program is a numerical model of the Mazzilli ZVS transformer driver inside the machine and it provides useful information about the voltages and currents involved depending on some circuit parameters. It’s found in appendix C.

LINK:http://www.mediafire.com/file/ah56thrfymxohj1/Design_and_Development_of_an_X-Ray_Machine%252C_Francisco_Piernas_Diaz.pdf/file

PhD Thesis High Frequency Modeling of Power Transformers under Transients -by Kashif Imdad-Universidad Politécnica de Cataluña

LINK: https://www.tesisenred.net/bitstream/handle/10803/457774/TKI1de1.pdf?sequence=1&isAllowed=y

Abstract

This thesis presents the results related to high frequency modeling of power transformers. First, a 25kVA distribution transformer under lightning surges is tested in the laboratory and its high frequency model is proposed. The transfer function method is used to estimate its parameters. In the second part, an advanced high frequency model of a distribution transformer is introduced. In this research, the dual resonant frequency distribution transformer model introduced by Sabiha and the single resonant frequency distribution transformer model under lightning proposed by Piantini at unloaded conditions are investigated and a modified model is proposed that is capable to work on both, single and dual resonant frequencies. The simulated results of the model are validated with the results of Sabiha and Piantini that have been taken as reference. Simulations have shown that the results of the modified model, such as secondary effective transfer voltages, transferred impedances and transformer loading agree well with the previous models in both, the time and frequency domains. The achieved experimental and simulated objectives of this research are:  Methodology for determining the parameters of a power transformer.  High frequency modeling of a transformer in order to simulate its transient behavior under surges.  Modification of high frequency model for single and dual resonance frequency. The originality and methodology of this research are:  High frequency transformer model is derived by means of the transfer function method. In the literature, the transfer function method has been used in many applications such as the determination of the mechanical deformations or insulation failure of interturn windings of transformers. In this thesis, the parameters of the proposed model are estimated using the transfer function method.  Modification of high frequency model for single/dual resonance frequency using the transfer function method. The transfer function can also be used to determine the state of the transformer. The modification in the developed model using the proposed technique has been validated (by simulations).

Design of 100kVA Ultra-High Efficiency Pole Transformer by Improving Eddy Current Losses Kim, Sang-Hyun Department of Electrical Engineering Graduate School of Soongsil University

                                     3-4 Estrutura do núcleo do transformador

 Design of 100kVA Ultra-High Efficiency Pole Transformer by Improving Eddy Current Losses Kim, Sang-Hyun Department of Electrical Engineering Graduate School of Soongsil University

ABSTRACT

In Korea, electricity demand is increasing due to industrial development and economic growth. Due to the increase in power demand, transmission and distribution losses are also increasing. The transmission and distribution loss rate in Korea is 3.6% of the total electric energy, of which about 2% is caused by losses in distribution transformers. Power transformers with high capacity and voltage have already achieved high efficiency through many studies. However, Pole transformers with low capacity and voltage are in fact lacking research on high efficiency despite the fact that about 2.2 million units are installed nationwide. The purpose of this paper is to design the ultra-high efficiency pole transformer that changes the core and winding materials and it - xii - reduces the eddy current loss of the winding and other structures for the 100kVA high efficiency pole transformer. In order to analyze the advanced technology, we analyzed overseas 100kVA high efficiency pole transformer and examined the technologies necessary for product development. In addition, The eddy current loss of low voltage windings and high voltage windings was calculated using a finite element method, and the eddy current loss was reduced by changing the shape of conductor, winding arrangement, and insulating paper. In order to reduce the eddy current loss of other structures, the loss was reduced either by inserting a nonmagnetic material between the low voltage bushing terminals or by changing the shape and material of the clamp. Finally, The iron core and winding materials of transformers were designed by using an amorphous core and copper conductor to maximize efficiency, and the 100kVA ultra-high efficiency pole transformer was designed by improving the eddy current loss of the windings and other structures. In order to verify the design, a transformer with the same specifications as the design model was manufactured to validate the effect, and compared with a high efficiency pole transformer, an efficiency of 99.56%(50% load) with an efficiency increase of 0.29% was developed. The eddy current loss reduction studies presented in this paper are expected to be used as data necessary for the development of transformers with other capacities. The final developed 100kVA ultra-high efficiency pole transformer is expected to contribute to improving the efficiency of the domestic distribution system

LINK ORIGINAL: http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=87c33062fa1d9da7ffe0bdc3ef48d419

LINK: http://www.mediafire.com/file/5z8z65z43a031c9/Design_of_100kVA_Ultra-High_efficiency.pdf/file

Toroidal Transformer Design Optimization for The Application of High-Frequency Power Converters BY Himanshu-Department of Electrical and Computer Engineering The Graduate School Pusan National University-2019

Toroidal Transformer Design Optimization for The Application of High-Frequency Power Converters BY Himanshu-Department of Electrical and Computer Engineering

The Graduate School Pusan National University-2019

Dissertation for the degree of Doctor of Philosophy

Abstract

The high-frequency-based inverter is used in renewable energy power sources for power transmission. However, power quality is compromised as a result of the increase in common mode noise currents by the high inter-winding parasitic capacitance in high-frequency link transformers. This fast voltage transient response leads to harmonic distortion and transformer overheating, which causes power supply failure or many other electrical hazards. This paper presents a comparative study between conventional and modified toroid transformer designs for isolated power supply. A half bridge high-frequency (10 kHz) small power DC–AC Voltage inverter was designed along with power source; a 680 W solar module renewable system was built. An FEM-simulation with Matlab-FFT analysis was used to determine the core flux distribution and to calculate the total harmonics distortion (THD). A GWInstek LCR meter and Fluke VT04A measured the inter-winding capacitance and temperature in all four transformer prototypes, respectively. The modified design of a toroid ferrite core transformer offers more resistance to temperature increase without the use of any cooling agent or external circuitry, while reducing the parasitic capacitance by 87%. Experiments were conducted along with a mathematical derivation of the inter-winding capacitance to confirm the validity of the approach.

LINK ORIGINAL:http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=79b3a1cb6ca326e0ffe0bdc3ef48d419

LINK:https://www.mediafire.com/file/7o3knzbx43lgenw/Toroidal_Transformer_Design_Optimization.pdf/file

NEWS, WEBINAR Las Nuevas Pautas Para la Educación en Ingeniería en Brasil -16 de Junio a las 11 AM EDT-Prof. Dr. Jose Roberto Cardoso

¿Cómo un país con 210 millones de habitantes, la octava economía más grande del mundo, que alberga compañías como Petrobrás, Embraer, Vale y tiene una de las agroindustrias más grandes del planeta, logró poner la ingeniería en crisis?

¿Qué sucede cuando un contingente de casi 1,5 millones de inscripciones en cursos de ingeniería se reduce, en solo dos años, al 60% de este contingente y, al mismo tiempo, el número de cursos nuevos casi se duplica en el mismo período?

Razones como la dificultad del curso, el costo de la matrícula, la crisis en la economía, no son suficientes para justificar esta crisis sin precedentes, en comparación con ejemplos de otros países que han pasado por situaciones similares y surgieron gracias a la promoción de la ingeniería.

Todos estos puntos serán discutidos en este seminario web, para presentar, no solo las herramientas que el gobierno, la academia y las empresas están utilizando para mitigar este problema, sino también los grandes desafíos que se enfrentan para ganar esta batalla.

Presentador : Prof. Dr. Jose Roberto Cardoso

Graduado en Ingeniería Eléctrica por la Escola Politécnica da Universidade de São Paulo (1974) y doctorado en 1986. Fue Profesor Visitante en el Grenoble-INP-Francia. Es profesor en la Universidade de São Paulo desde 1999, coordinador del Laboratorio LMAG de Electromagnetismo Aplicado y GLIP – Global Institut for Peace de la USP. Fue director de EPUSP de 2010 a 2014. Fue el fundador de SBMAG-Sociedade Brasileira de Eletromagnetismo. Profesor Cardoso fue galardonado en 2013 con el título de Ingeniero Emérito del Año por el Instituto de Ingeniería de São Paulo y con el título de Doctor Honoris Causa por Grenoble-INP en 2019.

REGISTRE-SE NA SEGUINTE PAGINA WEB:

http://www.ifees.net/las-nuevas-pautas-para-la-educacion-en-ingenieria-en-brasil/

Modeling and Design of Medium-Frequency Transformers for Future Medium-Voltage Power Electronics Interfaces DOCTOR OF SCIENCES of ETH ZURICH presented by THOMAS PAUL HENRI GUILLOD

Modeling and Design of Medium-Frequency Transformers for Future Medium-Voltage Power Electronics Interfaces DOCTOR OF SCIENCES of ETH ZURICH (Dr. sc. ETH Zurich) presented by THOMAS PAUL HENRI GUILLOD MSc ETH

Abstract

Newly available fast-switching Medium-Voltage (MV) Silicon-Carbide (SiC) semiconductors are setting new limits for the design space of MV converters. Unprecedented blocking voltages (up to 15 kV), higher switching frequencies (up to 200 kHz), higher commutation speeds (up to 100 kVμs), and high temperature operation can be reached. These semiconductors feature reduced switching and conduction losses and, therefore, allow for the realization of extremely efficient and compact MV converters. Moreover, the increased blocking voltage allows the usage of simple single-cell topologies for MV converters instead of complex multi-cell systems. Hence, the MV SiC semiconductors are interesting for many applications such as locomotive traction chains, datacenter power supply chains, collecting grids for renewable energies, high power electric vehicle chargers, and more-electric aircraft. Most of these applications require an isolated DC-DC converter for providing voltage scaling and galvanic isolation. However, the increased voltages and frequencies allowed by MV SiC semiconductors create new challenges for the design of Medium-Frequency (MF) transformers, which start to become the bottleneck of isolated DC-DC converters in terms of power density and efficiency. More specifically, the winding losses (due to skin and proximity effects) and the core losses (due to eddy currents and hysteresis) are rapidly increasing and mitigate the advantages (e.g., the reduced volt-second product applied to the magnetic core) obtained with the increased operating frequencies. Moreover, the MV/MF PWM voltages with fast switching transitions are also particularly critical for the insulation of MF transformers and can lead to additional losses, thermal breakdowns, and partial discharge induced breakdowns. Finally, the MF transformers of DC-DC converters should feature reduced losses (efficiencies above 99:5 %) in order to match the performance offered by the MV SiC semiconductors. The main focus of this thesis is, thus, set on the design of highly efficient MV/MF transformers employed in isolated DC-DC converters. First, a theoretical analysis of MF transformers is conducted in order to extract the fundamental performance limitations of such devices. The nature of the optimal designs is examined with analytical models, scaling laws, and numerical optimizations. Afterwards, several points are identified as critical and are studied in more detail. First, the impact of model uncertainties and parameter tolerances on MF transformers is examined with statistical methods in order to highlight the achievable modeling accuracy. Then, a 2.5D numerical field simulation method is presented for assessing the impact of non-idealities on the losses produced by litz wire windings (e.g., twisting scheme and pitch length). Afterwards, the impact of MV/MF PWM voltages with fast switching transitions on the insulation is examined. The electric field pattern is analyzed inside, at the surface, and outside the insulation and shielding methods are proposed. Finally, the dielectric loss mechanisms of dry-type insulation materials under PWM voltages is examined in detail. Different analytical expressions are proposed for extracting the insulation losses and it is found that the dielectric losses can be significant for MV/MF transformers operated with MV SiC semiconductors. Design guidelines are proposed for the selection of appropriate insulation materials for MV/MF applications and silicone elastomer is identified as an interesting choice. All the presented results are verified with measurements conducted on different MF transformer prototypes. The derived models and results are applied to a MV isolated DC-DC converter, which is part of a MV AC (3:8 kV, phase-to-neutral RMS voltage) to LV DC (400 V) Solid-State Transformer (SST) demonstrator. This SST is aimed to supply future datacenters directly from the MV grid. The considered 25 kW DC-DC converter operates between a 7 kV DC bus and a 400 V DC bus. The usage of 10 kV SiC MOSFETs allows for the realization of the converter with a single-cell DC-DC Series-Resonant Converter (SRC). The DC-DC SRC is operated at 48 kHz as a DC Transformer (DCX) and the modulation scheme, which allows for Zero-Voltage Switching (ZVS) of all semiconductors, is examined in detail. The realized MV/MF transformer prototype features a power density of 7.4 kW/l (121 kWin3, 4.0 kW/kg, and 1.8 kW/lb) and achieves a full-load efficiency of 99:65 %. The complete DC-DC converter achieves an efficiency of 99:0 % between 50 % and 100 % load with a power density of 3.8 kW/l (62W/in3, 2.9 kW/kg, and 1.3 kW/lb). The results obtained with the constructed DC-DC converter, which are significantly beyond the stateof- the-art, demonstrate that MV/MF transformers can utilize the possibilities offered by the new MV SiC semiconductors.

LINK: https://www.research-collection.ethz.ch/handle/20.500.11850/353785

Novel Hybrid Unidirectional Three-Phase AC-DC Converter Systems by KAZUAKI MINO-Swiss Federal Institute of Technology (ETH) Zurich

Novel Hybrid Unidirectional Three-Phase AC-DC Converter Systems by KAZUAKI MINO A dissertation submitted to Swiss Federal Institute of Technology (ETH) Zurich EIDGENÖSSISCHE TECHNISCHE HOCHSCHULE ZÜRICH for the degree of Doctor of Sciences Presented by Kazuaki Mino E.E., M.Sc., Tokyo Denki University born December 23, 1968 citizen of Japan Accepted Accepted on the recommendation of Prof. Dr. J. W. Kolar, Examiner Prof. H. Akagi, Co-Examiner

Abstract

In order to reduce harmonics, many rectifier topologies have been developing. Passive rectifiers, which employ only passive components, e.g. phase shifting transformers, diode bridges, and inductors etc., show some advantages concerning high efficiency, low EMC, low complexity, and high reliability. The passive components could be compact if mains frequency is high as in aircraft and micro gas turbine applications. However, the output voltage is unregulated. Furthermore, the input current of the passive rectifiers results in a staircase waveform which is not high quality if compared to active rectifiers. In this thesis, the drawbacks of the passive rectifiers are reduced. A diode bridge rectifier whose harmonics are reduced by adding an inductor to a diode bridge is widely used in motor drive applications. Mains current quality of the diode bridge rectifier is improved if a large inductance of the passive inductor is employed. However, the inductor is bulky, heavy and occupies a large space. In this thesis, the power density of the diode bridge rectifier is improved. The Electronic Smoothing Inductor, which is able to control a current to a constant value, is applied to the diode bridge output to act as a passive inductor. A control scheme for the DC-link voltage and active damping control for filter resonances are proposed. Moreover, the filtering concept is established to effectively attenuate EMI emission. The system dimensioning of the rectifier system is also introduced. A 5kW prototype shows a significant improvement in power density. The behaviours of the proposed rectifier system are tested by assuming practical conditions, e.g. not only ideal but also unbalanced and distorted input conditions. The dynamic behaviours are also evaluated. From the results, it is verified that the Electronic Smoothing Inductor has a similar characteristic to a passive inductor having a large inductance. Therefore, the proposed rectifier system brings a significant improvement in power density without impairing any features of a diode bridge rectifier. On the other hand, the passive 12-pulse rectifier can be extended to a hybrid rectifier having two active switches operated in an interleaved manner. The proposed topology ensures a controlled output voltage. Furthermore, modulation schemes to realize a purely sinusoidal input current are proposed. A 10kW prototype has been build with respect to future more-electric aircraft applications. The design procedure including the magnetic components and the active parts is introduced in this thesis. The proposed hybrid rectifier and the control schemes are verified by numerical simulations and experimental results. The output voltage is regulated. Furthermore, the input current is improved from a 12-pulse staircase shape to sinusoidal by the proposed triangular modulation. Moreover, the proposed closed loop control of input currents is performed to track a reference independently of mains voltages e.g. unbalanced and distorted input voltages. Therefore, both output voltage regulation and improvement of input current quality for the 12-pulse rectifier have been achieved by the proposed schemes. This thesis presents two rectifier systems which perform successfully. Both systems are hybrid and allow output power to flow without switching behaviours. Therefore, the proposed rectifier systems have not only high quality characteristics but also a high reliability. The system configurations, control schemes and their features are introduced. 

LINK http://www.mediafire.com/file/0tokqbgz47ukn4e/eth-144-02.pdf/file

Hybrid DC/DC Converter for Electric Vehicle (EV) On-Board Charger (OBC) Using Full-Bridge (FB) and Resonant Converter with Single Transformer Najam ul hassan Department of Electrical Engineering Graduate School, Myongji University

Hybrid DC/DC Converter for Electric Vehicle (EV) On-Board Charger (OBC) Using Full-Bridge (FB) and Resonant Converter with Single Transformer Najam ul hassan Department of Electrical Engineering Graduate School, Myongji University Advisor Professor Lee Jun-young

ABSTRACT

In this document a highly efficient hybrid DC/DC converter is proposed. Its design procedure, analysis and experimental results are presented by testing of the implemented prototype and. whole document is arranged into six chapters. Electrical vehicle battery chargers background, power level, different charging methods and purpose of the document is presented in chapter 1. High power DC/DC converter topologies suggested recently, and its benefits and drawbacks are briefly discussed in chapter 2. Proposed converter diagram, operational analysis and comparison of proposed converter with other DC/DC converter topologies are presented in chapter 3. Chapter 4 is about design procedure. Based on the design procedure suggested in chapter 4, prototype design and simulation results are given in chapter 5 and experimental results are given in chapter 6. Most of the previously proposed hybrid converters have used two transformers for each converter in hybrid structure that makes the size of the converter bulky and there was also low utilization and the power distribution problem between two transformers of the hybrid converters. To solve this problem, a new high efficient hybrid DC/DC converters using single transformer, which has characteristics of Full-bridge and resonant convertor for EV OBC, is proposed in this vii thesis. By using single transformer the power distribution problem has been solved and transformer utilization has become high. In the proposed converter, magnetizing inductance has been used at the primary side of the transformer to obtain the soft switching such as zero voltage switching (ZVS). Leakage inductance of the transformer has been used as resonant inductor on the secondary side to avoid the use of separate inductor as resonant. The prototype of 6.6KW has been implemented to verify the feasibility of the proposed converter and maximum efficiency of 97.4 is achieved at 413 V.

LINK http://www.mediafire.com/file/fd3hegpispv96nv/Hybrid_DCDC_CONVERTER_EV_CHARGER.pdf/file