• Journal of Power Electronics
• /
• 제18권4호
• /
• pp.1278-1292
• /
• 2018

Inductive power transfer (IPT) technology allows for charging of electric vehicles with security, convenience and efficiency. However, the IPT system performance is mainly affected by the magnetic coupling structure which is largely determined by the coupling coefficient. In order to get this applied to electric vehicle charging systems, the power pads should be able to transmit stronger power and be able to better sustain various forms of deviations in terms of vertical, horizontal direction and center rotation. Thus, a novel cross-shaped magnetic coupling structure for IPT charging systems is proposed. Then an optimal cross-shaped magnetic coupling structure by 3-D finite-element analysis software is obtained. At marking locations with average parking capacity and no electronic device support, a prototype of a 720*720mm cross-shaped pad is made to transmit 5kW power at a 200mm air gap, providing a $1.54m^2$ full-power free charging zone. Finally, the leakage magnetic flux density is measured. It indicates that the proposed cross-shaped pad can meet the requirements of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) according to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).

• 한국농림기상학회지
• /
• 제22권3호
• /
• pp.144-151
• /
• 2020

작물을 재배하는 동시에 전력 생산도 가능한 영농형 태양광 발전은 농업·농촌 분야와 재생에너지 산업 모두로부터 주목 받고 있다. 하지만, 그 역사가 짧은 만큼 영농형 태양광 하부에서의 미기상 환경 변화에 대한 이해와 관측 방법론이 정립되지 않은 실정이다. 따라서 본고에서는 보성군에 설치된 영농형 태양광에서 2019년 11월 부터 2020년 5월까지의 보리 생육기간 동안 일사광, 광합성유효복사광, 기온, 습도, 토양습도·온도, 풍향·풍속을 5분 간격으로 측정하여 공개했다. 또한, 노지의 일사량 및 광합성유효복사량에 대한 약 13일 간의 자료 결손에 대해서는 가까운 기상청 관측 자료를 활용하거나 영농형 태양광 하부의 자료를 이용한 두 가지 경험적 메우기 방법을 제안하였다. 본고 자료가 영농형 태양광에 대한 농업적 평가에 다양하게 활용되기를 기대한다.

• 항공우주시스템공학회지
• /
• 제12권2호
• /
• pp.1-6
• /
• 2018

위성의 자세제어 구동기에 사용되는 직접구동 모터(BLDC Motor)의 영구자석 자속밀도 분포 불균일은 위성 토크 리플을 발생시켜 자세에 지대한 영향을 미친다. 본 논문은 이러한 토크 리플을 줄이기 위해 영구자석의 형상, 배치, 공극에 따른 자속밀도를 이론과 유한요소법 시뮬레이션을 통하여 분석하고 가장 적합한 자석 형상조합을 찾고자 한다. 사각형과 아치형, 단일 자석 배치와 듀얼자석 배치형상의 자속밀도 성능비교를 통해 최적의 자석 배치형상을 구하였으며, 이의 검증을 위해 시제품 모터(Protype Motor) 제작을 통하여 성능을 검증하였다.

• 한국철도학회논문집
• /
• 제19권3호
• /
• pp.324-330
• /
• 2016

전자접촉기는 전기 회로에 사용하는 개폐기 중 하나로 산업계 전반에 걸쳐서 폭 넓게 사용되고 있다. 이 전자접촉기의 구동부인 전자코일은 전기 회로를 개폐하는 역할을 맡고 있고 전자접촉기의 동작 성능에 중요한 역할을 한다. 이 논문은 유한요소법을 이용하여 실험데이터를 반영한 해석 모델을 구현하였으며 인가전압과 권선수의 변화에 대한 전자기력의 특성 확인을 통해 해석 모델을 검증하였다. 두 전자코일의 구동 코어와 고정 코어의 접촉부 변화에 따른 전자기력의 특성을 연구하였다. Push형 솔레노이드 구조의 전자코일에서 두 코어 접촉부의 기울기에 따른 구조의 전자기력 특성을 접촉부의 자속밀도 분포를 통해 해석하였다. 또한 접촉부 사이 air gap의 변화에 의한 구조가 자속밀도 분포에 미치는 영향을 파악하였다. 이를 통하여 전자코일의 코어 접촉면에 따른 전자기력의 특성을 연구하였다.

• 대한기계학회논문집A
• /
• 제26권7호
• /
• pp.1232-1240
• /
• 2002

Recently, linear motors are applied to many small precision products. Thus high generating power with small size is required of it. In order to increase the motor efficiency, the design variables need to be optimized. In this study, Vector Fields FEM software, OPERA-3d, was used for simulating linear motor. The thrust and magnetic flux density at the air-gap center were simulated and compared with the experimental results. Taguchi method was applied to investigate the effects of each variables. As a result, the thickness of conductor and magnet was important for the thrust but the thickness of the yoke. The temperature of the conductor was determined by finding the thermal conductivity that was determined by experimentation. Correlation equation relating to the thrust and temperature was proposed by Latin square and Least Square method. The optimum design variables were determined by correlation equation, and compared with simulation results. According to this analysis, thrust force of linear motor was improved about 7% comparing with conventional model.

• 대한기계학회논문집A
• /
• 제24권11호
• /
• pp.2732-2741
• /
• 2000

Combination of magnetic recording technology and optical recording technology such as Near Field Optical Recording is watched recently. In order to accomplish this technology, the development of an electromagnetic driven mm-sized mirror shifting laser beam in track direction have to needed. In Near Field Optical Recording System, shifting laser beam in track direction mean as fine tracking and means as coarse tracking. Therefore in Near Field Optical Recording, 2-stage actuator is composed of servo controller in reading or recording information on disc layer. In our research, through design and simulation process of driven mm-sized mirror, we arrange systematically design process of driven mm-sized mirror having good frequency transfer characteristics. Design and simulation processes included modal analysis of spring, calculation of magnetic moment according to the number of turns and geometric configuration of coil and magnetic circuit analysis meaning that calculation of magnetic flux density in air gap of magnetic circuit. After that we design and make parts of driven mm-sized mirror, assemble and evaluate our electriomagnetic driven mm-sized mirror. we compared design values with actual characteristic values and present solution scheme. Through these processes we performed manufacturing of an electromagnetic driven mm-sized mirror having good frequency-domain characteristics and high sensitivity characteristics.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제54권8호
• /
• pp.370-376
• /
• 2005

The single-phase induction motor is simple and durable, but the efficiency is low. Therefore, electric motors like HLDC and LSPM(line-start permanent magnet motor) that use the permanent magnet have been studied. The most advantages of single-phase LSPM is having the same stator as the stator of the single-phase induction motor and permanent magnets are just inserted in the squirrel cage rotor of the single-phase induction motor. But the characteristics of single-phase LSPM synchronous motor has very complex characteristics until the synchronization and if the design is not suitable, the single-phase LSPM synchronous motor cannot be synchronized. We designed a single-phase LSPM using the same stator and winding as the conventional single-phase induction motor, but newly designed the permanent magnets considering air gap magnetic flux density. The transient characteristics of the single-phase LSPM is not good because of a magnetic breaking torque, however, it can be improved by redesigning the rotor bars. We are proposed the design method of rotor bar for the single-phase LSPM to start softly and to make synchronization easily.

• Journal of Magnetics
• /
• 제20권1호
• /
• pp.79-85
• /
• 2015

This paper presents a comparative study of a Tubular Linear Machine (TLM) with an Axially Magnetized Single-sided Permanent Magnet (AMSPM) and an Axially Magnetized Double-sided Permanent Magnet (AMDPM) based on analytical field calculations. Using a two-dimensional (2-D) polar coordinate system and a magnetic vector potential, analytical solutions for the flux density produced by the stator windings are derived. This technique is significant for the design and control implementation of electromagnetic machines. The field solution is obtained by solving Maxwell's equations in the simplified boundary value problem consisting of the air gap and coil. These analytical solutions are then used to estimate the self and mutual inductances. Two different types of machine are used to verify the validity of these model simplifications, and the analytical results are compared to results obtained using the finite element method (FEM) and experimental measurement.

• 한국전자통신학회논문지
• /
• 제17권6호
• /
• pp.1081-1088
• /
• 2022

동기발전기의 고조파는 철손과 동손을 증가시켜 발열의 원인이 된다. 이를 감소시키기 위하여 전기자의 권선법을 분포권, 단절권을 이용하여 고조파를 감소시키는 방법이 있으나 본 논문에서는 영구자석의 형상을 기존에 연구되었던 방법이 아닌 새로운 형상 변형을 통해 고조파를 감소시키며 기전압의 파형을 개선하고자 한다. 형상 변형 방법으로 영구자석의 양단을 절단하고 설정값에 따라 영구자석의 면적을 증가, 감소시켜 공극의 길이를 조절한다. 이때 자속밀도의 분포를 다르게 하여 이에 따른 기전압과 왜형률을 비교하였다. 이를 통해 논문에 기술된 영구자석의 형상 변화 모델들을 비교하고 가장 효과적인 변형 방법을 나타냈다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2005년도 학술대회 논문집
• /
• pp.95-99
• /
• 2005

This paper presents a general proposal to design and calculate the performance of a tubular permanent magnet linear generator treated here on the basis of the Finite Element Method. Optimizing the linear generator dimensions reduces the cogging force, which occurs due to the interaction between stator teeth and the permanent magnets. The generated AC voltage is analyzed and evaluated for both no load and load cases to take the armature reaction effects on the air gap flux density. A repetitive routine is followed to calculate the output AC voltage from the change of flux and the speed of the single-phase linear generator. The AC output voltage is calculated for different resistive loads, and hence, the linear generator load characteristic is obtained. The designed linear generator is capable to generate an output power of 5.3kW with AC output voltage of 222V with an efficiency of 96.8% at full load of 23.8A. The full load current is chosen based on the thermal properties of the coil wire insulations.