• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1903-1908
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• 2008

This paper presents a characteristics of linear induction motor considering airgap variation for railway transit in order to achieve high performance of the vehicle. The operating principle of a LIM(Linear induction motor) is identical to a rotary induction motor. Space-time variant magnetic fields are generated by the primary part across the airgap and induce the electro-motive force(EMF) in the secondary part, a conducting sheet. This EMF generates the eddy currents, which interact with the airgap flux and so produce the thrust force known as Loren's force. Even though the operating principal is exactly same as a rotary motor, the linear motor has a finite length of the primary or secondary parts and it causes static and dynamic end-effect which is the discontinuous airgap flux phenomenon. This end-effect causes the deterioration of the system performance, especially in high-speed operation. Another problem is that construction tolerance restricts the minimum airgap in order to prevent a collision between the primary part and the secondary reaction plate. More over, as the airgap length is getting smaller, the attraction force between the primary part and secondary parts is getting larger dramatically and the attraction force would be another friction against propulsion. Therefore, it is necessary to figure out the characteristics of linear induction motor considering airgap variation in order to achieve high performance of the vehicle. The dynamic model of LIM taking into account end-effects is derived. Then the modified mechanical load equation considering the effect of the attraction and thrust force according to the airgap variation is analyzed. The simulation results are presented to show the effect of the LIM according to the airgap variation.

• International Journal of Railway
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• 제8권1호
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• pp.15-20
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• 2015

As a result of the current population concentrations in urban centers, demand for intercity transportation is increasing rapidly. Railway transportation is becoming popular as an intercity transportation because of its timely service, travel speeds and transport efficiency. Among the many railway systems, the innovative and environmentally friendly maglev system has been rated very highly as the next-generation intercity railway system. Linear induction motors are widely used for the propulsion of maglev trains because of their light weight and low construction costs. The urban maglev that was recently completed in Incheon airport site employs a 110km/h class linear induction motor. However, this system was designed to meet requirements for inner-city operations and is not suitable as an intercity transportation system, which requires medium to high speeds. Therefore, this study deals with the characteristics and designs of linear induction motors used for the propulsion of maglev trains that can be used as intercity trains. Rail car specifications for high-speed trains have been presented, and the characteristics of linear induction motors that can be used for the propulsion of these trains have been derived using the finite element method (FEM).

• 전기학회논문지
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• 제62권5호
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• pp.723-729
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• 2013

This paper presents an parallel type Linear Induction Motor with ununiform airgap for a shallow-depth underground train with 100‰ grade and 15 m curvature. This parallel type LIM has enough gradability but has inherently ununiform airgap between center and end parts. Consequently, performance when the train passes curved section should be considered with transient analysis. Moreover, general parallel operation, 1C2M which is usually used for train operation, deteriorates LIM performance because of different line velocity between inner and outer LIMs. Transient analysis has many problems such as huge model, lots of meshes, very long calculation time, truncation error and so on. This paper has presented a novel technique using equivalent linear rotating model in order to solve these problems and has analyzed parallel type LIM by using the proposed technique. Finally, LIM performance according to independent operating control has been investigated.

• 한국산학기술학회논문지
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• 제12권8호
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• pp.3617-3625
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• 2011

본 논문은 기존의 복잡한 구조의 전통적인 엘리베이터 도어의 문제점을 개선한 리니어유도모터(LIM)를 적용한 단순 메커니즘 구조와 직접 구동의 신개념의 엘리베이터 도어시스템의 개발에 관한 것이다. 본 논문에서는 리니어 모터를 설치한 최적의 도어 구조와 리니어모터의 설계 결과를 제시하였으며 시험을 통하여 리니어모터의 설계결과의 타당성을 검증하였다. 또한 벡터제어에 의한 고성능 구동제어기 및 최적 운전 패턴을 제안하고 실제 제작되어 분석과 시험에 의해 리니어모터 적용 엘리베이터 도어시스템의 성능을 검증하였다. 본 논문에서는 제안된 리니어도어시스템의 설계와 제작과정에 대해서도 자세히 서술하였으며 시스템 주변장치 설계에 대해서도 기술하였다. 본 논문은 기존의 도어시스템의 문제점을 보완한 새로운 도어시스템의 기술적 기반을 마련하였으며 향후 신개념 엘리베이터 도어시스템 개발의 유용한 자료가 되리라 기대된다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.230-235
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• 2017

When the characteristics of a linear induction motor (LIM) are analyzed using finite element analysis (FEA), it is desirable to set the voltage source as an input. If the voltage source is set as an input in FEA, the leakage inductance and primary resistance of the equivalent circuit must be entered by direct calculation, and the magnetizing inductance and secondary reaction effects are directly considered in FEA. Exact calculation is necessary because the primary winding resistance and leakage inductance directly entered will have a significant effect on the LIM output. Therefore, in this study, we accurately calculated the primary leakage inductance and analyzed the resulting LIM characteristics. We calculated the leakage inductance using an analytical equation and FEA, and we confirmed the accuracy by comparing the results with the value experimentally calculated using a manufactured model. We also analyzed the instrument performance and thrust of the LIM as a function of the difference in the leakage inductance. Finally, we present the conclusions on the precise analysis based on the calculation of the leakage inductance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.251-251
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• 2010

Linear induction motor performance for a light-weight urban transit has been established and verified. In this paper, linear induction motor is analyzed by finite-element method to consider influence of construction of secondary reaction plate on the transverse edge effect. With this effective analysis method, various models with overhang and cap have been analyzed to consider the relationship between the construction of secondary reaction plate and the transverse edge effect.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 기술교육전문연구회
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• pp.127-131
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• 2003

LIM have mainly different point considering rotary induction motor, that is end effect. In this paper described that, end effect, adding to the rotary induction motor. They can designed because of affects magnetizing inductance and series resistance in the d-axis circuit. After LIM modeling, using SVPWM, apply to vector control this model. We can verify feasibility of field oriented control technology can control speed by simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1162-1164
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• 2005

A Linear Induction Motor that generates the direct thrust directly, is widely used for the operation system of electrified railroad, elevation system, conveyer system, and so on. There are two analysis methode of linear induction motor characteristics. One is the electrical magnetic analyzing, the other is analyzing equivalent circuit. The electrical magnetic analyzing methode has available advantages to consider the physical condition. The equivalent circuit analyzing methode has the elementary methode in the system of vector control and over shoot situation. In this paper, It is used the dynamic characteristic analyzing methode that can calculate efficiently the end effect by using equivalent circuit methode in the operating linear induction motor system modeling and doing simulation of output characteristics of vector controller.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.316-320
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• 2008

A light rail transit, using a linear induction motor, is generally composed with reaction plates along railroad track and the three phase primary on the vehicle. This linear induction motor is driven to keep clearance between the primary and the secondary of the ground for preventing any contact. Therefore efficiency and power factor is very low. In addition, the reaction plate installed on the ground throughout entire railway is impossible to keep uniform gap and it may cause system deterioration. In this paper, A rotary-type small-scale model of a linear induction motor for various characteristic analysis is designed. Thrust force, normal force and input current of the model by air-gap variation have been analyzed by using a Finite Element Method (FEM). The effects of air-gap variation on system performance have been considered by analysis results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1099-1100
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• 2011

This study deals with the dynamic characteristics analysis of Linear Induction Motor (LIM) using finite element method in which the moving mesh technique is considered. The focus of this paper is to show the appropriate of on-line observer system for position sensorless control of a LIM under the phase asymmetry, saturation and iron loss. Comparisons are given with angle of the observer and that of proposed FEA method of linear induction motor, respectively. The position sensorless control system is realized, and the effective of the observer system is verified by experimental results.