Research on performance improvement and industrial application of static electromagnetic equipment using iron-based amorphous alloys-Doctoral Dissertation (Thesis(doctor)----Tohoku University-2019-JAPAN

 

Research on performance improvement and industrial application of static electromagnetic equipment using iron-based amorphous alloys-Doctoral Dissertation (Thesis(doctor)----Tohoku University-2019-JAPAN

ABSTRACT：Iron-based amorphous alloy has the advantages of lower iron loss and higher permeability compared with conventional grain-oriented silicon steel due to disappearance of magnetocrystalline anisotropy derived from randomly aligned magnetic atoms. One can expect for considerable improvementinpower efficiency of presently commercialized staticelectromagnetic machinessuch as distribution transformer and filtering reactor for inverter system by replacing the core material from silicon steel to iron-based amorphous alloy. Moreover, the material’s satisfactory performance at higher frequency enables application to the fieldof next generationin power distribution system. However, the commercially available iron-based amorphous alloy produced with meltquenching method has a shape of 20 to 30 m-thick thin foil; the coremade from the stacked and wound several hundred to thousand foils isfragile. This form of amorphous core causes difficulty in mass-production of the low cost and larger power capacity electromagnetic machines. Consequently, the range of industryapplication of amorphous alloy has been limited at present. Hence, this study aims at contribution to the savings of energy and CO2emission by theproposalsof low cost structures and design methodologies of three typesof amorphous electromagnetic machinethoseenable extensions of power capacity and excitation frequency. Additionally,the effect of improvement inpower efficiencies of them isdemonstrated by way of prototype tests. This thesis consists of six chapters;the research results are shown in accordance with the following organization. The chapter 1 describes the background and the objective of this study. The chapter 2 describes conventional technology and problems of amorphous electromagnetic machines. First, the advantages and disadvantages of presently mass-produced iron-based amorphous alloy were organizedcomparing the magnetic and physical properties of it with those of conventional grain-oriented silicon steel. Then, this chapter reviewed production methods of presently commercialized amorphous electromagnetic machinesandclarified the problems to be solved for extension of range of industryapplication. The chapter 3 describes the development of larger capacity distribution transformer with amorphous wound cores as the first case. This study considered a 30 MVA classed three phase amorphous core transformer that was not implementedup to nowbecause of structural problems, and proposed a structure that supports the fragile core while suppressing increase of iron loss. In advance of design, an estimation method of iron loss taking thecompressive stressin the core into account was established, which enabled the quantification of relationship between support method of larger wound core and its iron loss. The cores were divided into inner and outer components suspended independently; thedesign buffered the compressive stress affected in the cores and reduced the iron loss by 32% compared with that with a conventional support structure. In addition, providing the shielding components where the leakage field is concentrated resulted in 66% decrease in strayloss by utilizing the electromagnetic analysis. Then, a proposed support structure including 10 MVA single phase three legs amorphous core and windings were manufactured separately, and loss performancesof them were evaluated. This study determined totalloss at a load factor of 50% using measured values of iron loss and copper loss and analytical values of stray loss assuming an averaged load operating condition of transformer; as a result, the totalloss in a 30 MVA three phase amorphous core transformer could be reduced by 35% against a conventional silicon steel core transformer of same power capacity. The chapter 4 describes the development of amorphous core reactor for filtering component in uninterruptible power system (UPS) as the second case. This study invented two types of core structure for low cost and larger capacity three phase AC reactors formed from the toroidally wound amorphous yoke cores and the magnetic leg cores cut from solidified toroidal amorphous cores. Calculation models of iron loss in the cores and gap loss induced from the fringing flux between core components were established on the basis of a technique for extracting the coordinate components of the magnetic flux density in accordance with the anisotropic magnetization curvesin plane and laminated directionsof the amorphous foils. It was confirmed that the calculated iron losses at utility and carrier frequencies agree with measured losses within a 10% error. The prototyped amorphous reactors had approximately half the total losses of that of a conventional silicon steel core reactor and increased the power efficiency of the 400 kVA UPS by up to 0.55%. Furthermore, this study demonstrated the practicalityof aminiaturized amorphous reactor designed with a magnetic flux density of 1.2 T increased from standard oneof 0.8 T. It was verified that total loss and unit volume of the prototyped miniaturized reactor could be reduced by 35% and 43% respectivelycompared with those of a silicon steel core reactor. The chapter 5 describes the development of high frequency amorphous transformer for isolated DC-DC converter in DC-interconnected offshore wind farm system as the third case. This study designed and prototyped a core-type 3 kHz-excited 500 kVA transformer consisting of a single phase lap-joint amorphous wound core and windings with primary and secondary copper (Cu)sheets wound alternately in turns. The alternately wound winding structure suppressed the proximity effect between Cu sheets and the in-plane eddy current due to the fringing flux crossing the edge of sheets and fixtures, and the copper loss at 3 kHz was 61% lower than that of conventionally designed winding with primary and secondary sheets wound continuously. The rated total loss of the transformer with alternately wound windings was 21% lower than that of a conventional one. Furthermore, this study proposed a guideline for iron loss-reducing design of the lap-joint part in the amorphous core based onthe measured iron loss at high frequencies and the results of electromagnetic analysis. The chapter 6 concludes the loss reduction effect of three types of amorphous electromagnetic machinedeveloped in this study and describes the remaining issues.

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博士論文 Doctoral Dissertation 電気自動車の走行中ワイヤレス給電における 制御設計とシステム構築に関する研究 Study on Control Design and System Implementation for In-motion Wireless Charging of Electric Vehicles-------東京大学大学院 工学系研究科 電気系工学専攻 Department of Electrical Engineering, Graduate School of Engineering, The University of Tokyo

 

OVERVIEW

This paper is about wireless power transfer technology that charges electric vehicles while they are running. The system is now stuck with the stationary wireless power supply system, which previously stopped and slowly charged the vehicle. Concerning control design and system construction based on a new perspective that focuses on very different dynamic characteristics. The aim is to establish technology that will The practical application of wireless power transfer technology while driving will accelerate the spread of electric vehicles. It could become a ground-breaking technology that will give a strong boost and bring about a paradigm shift in the current automobile society. This paper In this section, we will discuss the issues required for wireless power transfer technology while driving, and provide clear solutions for these issues. We will present our approach and clarify the effectiveness of these approaches through demonstration experiments. In addition, control design By presenting the knowledge obtained in the form of system construction, we cover a wide range of topics from theory to application. We hope that this paper will make a major contribution to society or be a step toward popularization. The content and structure of this paper are shown below. Chapter 1 deals with the electrification of cars towards a decarbonized society, and discusses current high-performance batteries and Rather than research and development with fast charging as the key technology, we are developing a new vehicle based on motors, capacitors, and wireless technology. Show about Ma society. Here, cars of the future will be powered by highly responsive electric motors rather than engines. Fast charging, using long-life, high-power capacitors instead of lithium-ion batteries. Instead, wireless power supply, which charges slowly while running, plays a major role. wireless power transfer If infrastructure and cars are connected by technology, the cruising range on a single charge, which is tied to battery performance, will lose meaning. The convenience of electric cars will improve dramatically. On the other hand, energy storage devices that require frequent charging and discharging The chair has the advantage of using physical battery capacitors rather than chemical batteries, which have a short lifespan. However, all Since it is difficult to electrify roads, it is not possible to save enough energy to get from the main road to your home. Large capacity capacitors such as electric double layer capacitors are suitable. Finally, the electric motor Advanced motion control realizes safe and eco-friendly driving, and this technology has produced many results in our laboratory. It is proven. Therefore, in order to create this new car society, wireless power transfer technology is essential. It is essential to establish wireless charging while stationary, and what is particularly important here is wireless charging while stationary, which replaces quick charging. This technology is not a wireless power transfer technology that connects a moving vehicle to infrastructure. Na Oh, you can only receive power from one power transmitter for a few seconds to a few tens of seconds at most while driving on a highway. When driving at high speeds, power cannot be received for even a few seconds, so control on the order of milliseconds must be achieved. stomach. The essence of the technology for wireless power transfer while driving is to realize this instantaneous power transfer. It also makes clear that there are many issues that need to be resolved. In this paper, we will address the issues presented in Chapter 1. Each chapter presents a clear approach. ​

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Mémoire de Master en Electrotechnique Présenté par : TOUHAMI Sarah Asma Intitulé Modélisation des transformateurs : Etude de l’hystérésis et de la saturation magnétique

 

Mémoire de Master en Electrotechnique Présenté par : TOUHAMI Sarah Asma 

Intitulé Modélisation des transformateurs : Etude de l’hystérésis et de la saturation magnétique Président du jury : S. MEKHTOUB Professeur Ecole Nationale Polytechnique

 Examinateurs : A.BOUBAKEUR Professeur Ecole Nationale Polytechnique

 H.SAHRAOUI Maitre de conférences Ecole Nationale Polytechnique 

 Abstract— The objectif of this work is the modeling and analysis of transformers. In this study the hysteresis, the saturation and the modeling have been widely discussed. Experimental tests and numerical simulations on models adjusted Software EMTP (Electromagnetic Transients Program) were conducted and the comparison of obtained results confirmed the validity of what we have made as a correction of this software specially designed for large electrical networks.

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Méthodologies de Conception de Transformateurs Moyenne Fréquence pour application aux réseaux haute tension et réseaux ferroviaires Alexis Fouineau--THESE de DOCTORAT DE L’UNIVERSITE DE LYON opérée au sein de l’Université Claude Bernard Lyon 1 Ecole Doctorale N° 160 ECOLE DOCTORALE ELECTRONIQUE, ELECTROTECHNIQUE, AUTOMATIQUE DE LYON Spécialité de doctorat : Génie Électrique Soutenue publiquement le 13/11/2019, par : Alexis FOUINEAU

 

Méthodologies de Conception de Transformateurs Moyenne Fréquence pour application aux réseaux haute tension et réseaux ferroviaires

THESE de DOCTORAT DE L’UNIVERSITE DE LYON opérée au sein de l’Université Claude Bernard Lyon 1 Ecole Doctorale N° 160 ECOLE DOCTORALE ELECTRONIQUE, ELECTROTECHNIQUE, AUTOMATIQUE DE LYON Spécialité de doctorat : Génie Électrique Soutenue publiquement le 13/11/2019, par : Alexis FOUINEAU opérée au sein de l’Université Claude Bernard Lyon 1 Ecole Doctorale N° 160 

ECOLE DOCTORALE ELECTRONIQUE, ELECTROTECHNIQUE, AUTOMATIQUE DE LYON

Spécialité de doctorat : Génie Électrique Soutenue publiquement le 13/11/2019, 

par : Alexis FOUINEAU

Abstract

 Medium Frequency Transformers (MFT) are an innovative technology compared to low frequency transformers, with the promise of reduced volume and increased efficiency. This PhD thesis focuses in particular on their design for high voltage, high power applications, such as high voltage and medium voltage DC networks, as well as railway networks. In these applications, MFTs are used in converters that can generate specific constraints to be taken into account during their design: non-sinusoidal signals, polarization voltage, target inductance values. Moreover, the technological choices currently available for the realization of MFTs are numerous, and there is currently no consensus on any technology for any given application. Trends could be identified using a tool to classify MFT designs from the literature. Thus, the most promising technologies were selected and retained for the future. Based on these technologies, a design methodology was developed to quickly and semi-automatically design and compare MFTs with different technological choices. It consists of three steps: pre-design, analytical design, and validation. The complete analytical design of the MFT with different technological choices is carried out using an automated design tool developed during this thesis, named SUITED (SUpergrid Institute TransformEr Design). This methodology requires models and data for each of the components and phenomena of the MFT. Concerning the magnetic core, a review and selection of models from the literature were carried out for the evaluation of the magnetizing inductance and magnetic losses. In addition, magnetic characterizations have made it possible to highlight the impact of certain technological processes on the levels of loss of magnetic cores made of nanocrystalline material, which is an excellent candidate for MFTs. Concerning the windings, analytical models to calculate the magnetic field, leakage inductance and skin and proximity effects were developed and compared with those in the literature and simulations. These models are proving to be more accurate on the MFT geometries considered. On top of that, a new method for evaluating the parasitic capacitances of windings with rectangular turns has been successfully implemented and validated. Thermal networks have been identified for the different MFT geometries. The thermal resistances of conduction, convection and radiation are calculated from detailed models. In particular, the anisotropy of materials is taken into account for thermal conduction, and the convection coefficients are evaluated via different correlations for each face of the MFT. The thermal networks are then solved iteratively and analytically to take into account the non-linearity of the thermal resistances while optimizing the required computation time. Finally, this entire design methodology was applied to three case studies corresponding to the target applications: high voltage, medium voltage and rail. The results obtained do show the performance and necessity of this approach.

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Medium Frequency Transformer Leakage Inductance Modeling and Experimental Verification M. Mogorovic and D. Dujic--POWER ELECTRONICS LABORATORY ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE--

2017 IEEE Energy Conversion Congress and Exposition (ECCE) 

Medium Frequency Transformer Leakage Inductance Modeling and Experimental Verification 

M. Mogorovic and D. Dujic 

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 Abstract—This paper provides detailed analytical modeling and finite elements method (FEM) analysis of the medium frequency transformer (MFT) leakage inductance, as one of the key design factors governing the operation of galvanically isolated power electronics converters. Precise leakage inductance modeling in design stage is especially important for converter topologies based on resonant conversion where MFT is a part of a resonant circuit. A comprehensive analytical model that takes into account both the geometric and frequency effects on the given MFT leakage inductance is generated based on the transformer physical structure, thus allowing for optimization of the MFT design with targeted equivalent circuit leakage inductance reference. The derived models are benchmarked to the measurement results on the developed MFT prototype.

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