There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

This paper reviews the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrids. Charger systems are categorized into off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports battery energy injection back to the grid. Typical on-board chargers restrict power because of weight, space, and cost constraints. They can be integrated with the electric drive to avoid these problems. The availability of charging infrastructure reduces on-board energy storage requirements and costs. On-board charger systems can be conductive or inductive. An off-board charger can be designed for high charging rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3 (fast) power levels are discussed. Future aspects such as roadbed charging are presented. Various power level chargers and infrastructure configurations are presented, compared, and evaluated based on amount of power, charging time and location, cost, equipment, and other factors.

/pdf/review-of-battery-charger-topologies-charging-power-levels-85yy2igx2w.pdf

Review of Battery Charger Topologies, Charging Power Levels, and Infrastructure for Plug-In Electric and Hybrid Vehicles

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

Energy storage systems (ESSs) are enabling technologies for well-established and new applications such as power peak shaving, electric vehicles, integration of renewable energies, etc. This paper presents a review of ESSs for transport and grid applications, covering several aspects as the storage technology, the main applications, and the power converters used to operate some of the energy storage technologies. Special attention is given to the different applications, providing a deep description of the system and addressing the most suitable storage technology. The main objective of this paper is to introduce the subject and to give an updated reference to nonspecialist, academic, and engineers in the field of power electronics.

Energy Storage Systems for Transport and Grid Applications

The issue of renewable energy is becoming significant due to increasing power demand, instability of the rising oil prices and environmental problems. Among the various renewable energy sources, fuel cell is gaining more popularity due to their higher efficiency, cleanliness and cost-effective supply of power demanded by the consumers. This paper presents a comprehensive review of different fuel cell technologies with their working principle, advantages, disadvantages and suitability of applications for residential/grid-connected system, transportation, industries and commercial applications. Development of mathematical model of fuel cell required for simulation study is discussed. This paper also focuses on the necessity of a suitable power-conditioning unit required to interface the fuel cell system with standalone/grid applications.

A review on fuel cell technologies and power electronic interface

The purpose of this paper is to provide the unbalanced magnetic force and vibration mode comparison between two large interior permanent magnet machines(IPM) with different pole-slot combination considering stator and rotor eccentricity. Due to the punching tolerance, the mixed eccentricity of air-gap is inevitable. It will generate the asymmetric magnetic flux density in air-gap, which makes the unbalanced magnetic pull and vibration. The study is focused on the unbalanced magnetic force and their harmonic components according to eccentricity conditions such as static, dynamic and mixed. When the high vibration is produced especially resonance, the obtained results provide clues what eccentricity condition occurs in the machine.

/pdf/analysis-of-electromagnetic-vibration-sources-in-100kw-21bso9eolv.pdf

Analysis of Electromagnetic Vibration Sources in 100kW Interior Permanent Magnet Motor for Ship Anti-heeling Pump Considering Eccentricity

In this paper, 3-D Equivalent Magnetic Circuit Network (EMCN) is used to solve detailed field computation considering asymmetric lateral displacement. The purpose of this paper is to analyze lateral and levitation characteristics of permanent magnet linear synchronous motor (PMLSM) by using 3-D EMCN and propose an optimal control scheme in controlled magnetic levitation stage considering the asymmetrical state.

http://ieeexplore.ieee.org/iel5/8707/27573/01230382.pdf

Levitation and recovery force analysis of controlled linear synchronous motor by using 3-D EMCN

The distribution of radial force density in brushless permanent magnet DC motor is not uniform in axial direction. The analysis of radial force density has to consider the 3-D shape of teeth and overhang, because the radial force density causes vibration and acts on the surface of teeth inconstantly. For the analysis, a new 3-D equivalent magnetic circuit network method is used to account the rotor movement without remesh. The radial force density is calculated and analyzed by Maxwell stress tensor and discrete Fourier transform(DFT) respectively. The results of 3-D equivalent magnetic circuit method have been compared with the results of 3-D FEM. Index terms-Brushless DC motor, distribution of radial force density, vibration, remesh, DFT, 3-D EMCN, 3-D FEM.

Dynamic Analysis of Radial Force rushless DC Motor Using 3-D Equivalent gnetic Circuit Network Method

A motor assembly for driving the blower of a fuel cell system is provided to absorb and inhibit the vibration of a rotation axis due to high speed rotation, thereby stabilizing the operation of a blower. A motor assembly for driving the blower of a fuel cell system comprises a hollow cylinder-shaped fixed cover(100); a stator core(110) installed at the outer circumference of the fixed cover and having a wound coil; a rotation axis(120) so as to inserted into the hollow of the fixed cover; a first bearing(141) inserted into the one end of the hollow of the fixed cover to support the rotation axis; a second bearing(142) inserted into the other end of the hollow of the fixed cover to support the rotation axis; an elastic member compressing the first bearing to the one end of the hollow; a rotation cover(130) having a penetration hole where the one end of the rotation axis is inserted and surrounding the core; a permanent magnet(170) fixed so as to face with the core each other at the rotation cover; a hole sensor(180) sensing the rotation displacement of the permanent magnet; and a control board(200) for controlling the power applied to the coil of the stator core according to the rotation displacement.

Motor assembly for driving air blower in fuel cell system

- This paper is about design of optimal structure of slot antenna array antenna with inner waveguide in accordance with the slot model, and fabrication of its prototype sample operating at the frequency of 24 GHz. Results of this work can be employed as a useful tool to develop and diversify slot antenna having superior performance and omni-directivity to that of current antenna. The implemented antenna demonstrates ultra-wideband performance for frequency ranges 24 GHz with the relatively high and flat antenna gain of 18.64dBi and low sidelobe levels. In addition, a 2×8 antenna array for phased-array systems and mm-wave sensor applications is also presented.Key Words : Slot Antenna, Millimeter-Wave, Waveguide, Automotive Radar System, Transverse†교신저자, 정회원 : 울산대학교 전기전자정보시스템공학부부교수E-mail : bywokim@ulsan.ac.kr*정 회 원 : 울산대학교 전기전자정보시스템공학부 조교수접수일자 : 2010년  8월  6일최종완료 : 2010년 10월 23일 1. 서 론 전파 전송을 담당하는 안테나는 일반 이동통신을 비롯하여 자동차, 항공, 국방에 걸쳐서 모든 산업에 활용되고 있다. 자동차인 경우에도 타이어 공기압 검지 장치(TPMS), 스마트키 시스템을 비롯하여 차간거리 경보 및 제어 장치에 까지 다양하게 적용되고 있다. 자동차 차간거리 경보 및 제어 시스템에 적용되고 있는 밀리파 레이더의 안테나 방식은 일반적으로 도파관 캐비티 슬롯 안테나를 사용하고 있다. 슬롯 안테나는 급전부와 방사체의 모양과 종류에 따라 구분이 된다. 급전부를 마이크로 스트립 라인으로 사용하는 것은 마이크로 스트립 슬롯 안테나(MAS : Microstrip slot antenna)라고 부르고 급전부를 도파관으로 사용하는 것은 도파관 슬롯 안테나(WSA : Waveguide slot antenna)라고 부른다. 직렬슬롯(Transverse slot)은 1946년 Waston이 등가 전송선에서 직렬성분관련 성분으로서 도파관 슬롯을 처음 논의했다. 슬롯의 임피던스에 관한 근사 표현은 Stevenson과 Oliner에 의해 유도 되었다.[1] 기존 연구에서는 전형적인 전계 분포를 가정하는 슬롯 길이의 함수로써 슬롯 임피던스에 대한 표현을 했다.[2] 또한, 사각 도파관에서의 직렬슬롯(Transverse slot)의 임피던스를 계산하는 방법과 펄스 확장 모멘트 방법에서 수렴(Convergence)을 얻기 위해 슬롯 사이드에 따른 등가 에너지 전류를 소개했다.[3] 그리고 펄스 확장과 포인트 매칭을 가진 모멘트 방법을 사용하여 벽면 두께 제로에 대한 직렬 슬롯 임피던스를 계산했다. 직렬 슬롯에서 배열 안테나로까지의 정확한 해석은 Josefsson에 의해 이루어졌다.[4], [5] 그러나 기존 연구에서는 주로 직열 슬롯 방식을 중심으로 연구가 진행되었으나 최근 강화되고 있는 자동차 업계의 기술요구를 충분히 반영하고 있지 못하고 있다. 이에 본 연구에서는 병렬 슬럿 방식의 안테나 설계 및 최적화 방안에 대한 연구를 실시하고자 한다.

Jin Hur

Papers

Analysis of Electromagnetic Vibration Sources in 100kW Interior Permanent Magnet Motor for Ship Anti-heeling Pump Considering Eccentricity

Levitation and recovery force analysis of controlled linear synchronous motor by using 3-D EMCN

Dynamic Analysis of Radial Force rushless DC Motor Using 3-D Equivalent gnetic Circuit Network Method

Motor assembly for driving air blower in fuel cell system

Radiation Characteristics of Parallel Slot Antenna for Automotive Radar System