• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 B
• /
• pp.604-606
• /
• 2002

Air-cored machines have a higher efficiency with high frequency. speed than iron-cored machine because of the iron losses which may produce too much heat as well as the copper losses occurred in the rotor winding. But air-cored machine is lower flux than iron machine. The nature of the machine from 'iron-cored' to 'air-cored' is a progressive feature in the machines. A general analysis of the fields that is applicable to all configurations is presented. Slotless machines have been applied for no ripple induced voltage. In this paper, slotless mahcines equipped with internal 4-pole amature winding. This paper pay attention to analyze flux density of air-cored and iron-cored synchrous machine analytically and compare flux density of aired-cored machine to iron-cored machine.

• 한국초전도ㆍ저온공학회논문지
• /
• 제22권2호
• /
• pp.38-43
• /
• 2020

This paper presents comparative research on characteristics of air-cored and iron-cored high-temperature superconductor (HTS) field winding synchronous motors. The 100 kW air-cored model is designed analytically by Spatial Harmonic Method, and based on this model, the iron-cored model having the same output power is designed for comparison. Due to the substantial difference of permeability property between air and iron-core, there is a difference of magnetic field magnitude and angle with respect to the HTS tape c-axis, resulting in a different critical current of the field winding considering the anisotropic property of HTS tape. For a detailed comparison between two models, the following key motor characteristics are calculated through the Finite Element Method (FEM) simulation: 1) critical current; 2) HTS wire length; and 3) torque characteristics. From the simulation results, it can be confirmed that the critical current value of the iron-cored model increases by 33 %. Also, in the case of the superconducting wire consumption, those of the iron-cored and air-cored models are 95.3 m and 815.6 m, respectively. So the wire usage can be reduced to about 88 % by using iron core. However, in terms of torque characteristics, the torque ripple of the iron-cored model is about twice as large as that of the air-cored model, which may be a disadvantage on vibration and acoustic noise.

• 전자공학회논문지SC
• /
• 제47권2호
• /
• pp.1-7
• /
• 2010

본 논문은 Air-cored induction 코일 센서의 고주파 동작 특성에 대한 실험적 관계식을 제시한다. Air-cored induction 코일 센서는 입, 출력 간 선형성이 좋고 저주파 영역에서 정확한 출력 특성 예측이 가능해서 널리 사용되지만 민감도가 낮다는 단점이 있다. 반면, 고주파 영역에서는 코일 센서 구성상의 기생효과로 인해 민감도가 크게 향상되지만 인가되는 자기장 주파수에 대한 출력 민감도의 의존성으로 인해 사용이 제한되어 왔다. 그러나 최근 고정된 주파수의 자기장을 대상으로 하는 비파괴 자기 검사법에서 검사 성능을 향상시키기 위하여 이와 같은 코일 센서의 고주파 특성을 이용하기 시작하였는데 코일 센서를 고주파 영역에서 사용하기 위해서는 고주파 영역에서의 센서 특성에 대한 예측이 요구된다. 본 논문에서는 다양한 코일 센서의 구성 조건하에서 코일 센서의 주파수 응답 특성을 측정하고 이 측정 결과를 기반으로 하여, 민감도가 최대가 되는 공진 주파수와 최대 민감도를 코일 센서 단면의 지름, 권선 지름, 그리고 권선 수와 같은 구성 파라미터의 함수식으로 근사하였다. 함수식은 실험결과를 잘 반영하며, 추론된 함수식으로부터 원하는 사양을 가지는 코일 센서의 구성 방안 및 관련 회로 설계 사양을 얻을 수 있다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권3호
• /
• pp.101-106
• /
• 2001

Air-cored superconducting synchronous generator(ASSG) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, in the case of the shape optimum design of ASSG, other design variables different from an iron-cored machine should be considered, which will lead to substantial improvement on the performance. The major design variables that are considered by using Three-dimensional Finite element Method(3D FEM) in this paper are : 1) field coil width, 2) axial length of magnetic shield, and 3) armature winding method. End-ring of armature winding is considered in the calculation of EMF. When it comes to field coil width, as field coil width enlarges, its effective field increases but the maximum field on the superconductor decreases. this determines the critical current density. this study presents an effective field coil width, axial length of magnetic shield, and armature winding method, and also the analysis is verified by the experimental results.

• 전기학회논문지
• /
• 제59권5호
• /
• pp.939-944
• /
• 2010

A high voltage air-cored helical strip/wire type pulse transformer has been fabricated for charging of a high voltage pulse forming line. As a primary coil, copper strip of 25mm width was wound helically around a MC nylon cylinder. For a secondary coil, copper enameled wire of 1mm diameter was wound around conical cylinder in order to provide insulation between two windings. The coupling coefficient of 0.53 was obtained when two coils were combined coaxially in the insulation oil filled chamber. Voltage gain and energy transfer efficiency were investigated by varying the parameters of primary and secondary circuit. Test results shows that the voltage gain increases up to 17 with increasing the primary capacitance up to 200nF. And highest energy transfer efficiency of 44% was obtained when the dual resonant operation condition was nearly satisfied. The pulse transformer developed in this study can be used for charging the middle conductor of a Blumlein pulse forming line.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.116-118
• /
• 2003

The Slotless Permanet-magnet linear synchronous motors (PMLSM) have been developed for factory automation, transportation applications, wafer steppers, conveyance system, and so on[1]. The current analysis and design are treated in air-cored PMLSM. The main purpose of this paper is to provide a general design and analysis framework for the iron-cored linear permanent-magnet machines. Based on field solution using two dimensional analytical technique the magnetic field required magnet volume size, optimal winding thickness size, winding flux linkage and thrust will be discussed.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• 제5B권1호
• /
• pp.27-33
• /
• 2005

The development of modern high-energy magnet materials has allowed the replacement of field coils in many different types of electromagnetic energy conversion machines. As well, the linear synchronous motor has recently been proposed for linear motion with high efficiency and thrust. Thus, this paper presents an analytical solution for the high thrust and cost reduction of the Iron-Cored Permanent Magnet Linear Synchronous Motor (PMLSM) considering magnetization arrays and geometry. Hence, the superior utilization points in each of the magnetization arrays are provided by the height ratio of the magnet/air-gap and magnet/winding coil, etc. In formulation, the space harmonic method in analytical solutions and the generalized 2-D tensor finite element analysis can be used to evaluate force components in magneto static devices including the magnetostrictive phenomenon.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.92-94
• /
• 2004

This paper presents modeling of dynamic system for slot less air-cored PM linear synchronous motor using space vector PWM. The vector control requires Information about rotor position. And we can need to the Hall sensor for sampling current. In order to agree with this purpose, Digital Signal Processor(TMS320F2406A) developed for implementation of a speed Field Oriented Control.

• 한국초전도ㆍ저온공학회논문지
• /
• 제10권3호
• /
• pp.14-18
• /
• 2008

This paper deals with the conceptual design and characteristic analysis of core type superconducting motor using iron cores in the field. As the objective function of conceptual design, the flux quantity per pole is selected. In order to reduce the quantity of superconductors, the variations of flux quantity per pole by changing the design variables and area are investigated. Finally, the quantity of superconductors between air-cored and core type superconducting motor is compared under the same motor capacity. In addition, the dimensions and volumes of motors are compared.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 B
• /
• pp.1054-1056
• /
• 2003

The slotless Permanent-Magnet Linear Synchronous Motors (PMLSM) have been developed for factory automation, transportation applications, wafer steppers, conveyance system, and so on. The current analysis and design are treated in air-cored PMLSM. This paper presents a design and analysis solutions for the general class of iron-cored Permanent magnet Linear Synchronous motor (PMLSM). In our design and analysis, rotor consisting of permanent magnets and slot less iron-cored coil stator are treated in a uniform way via vector potiential. For one such motor structure we give analytical formulas for its magnetic field, opitimal permanent magnet and winding coil thickness, trust force. We also provide comparisons of three types in Halbach, vertical, and horizontal magnet array.