• Journal of the Korean Society for Railway
• /
• v.13 no.4
• /
• pp.404-411
• /
• 2010

Authors conducted a deduction and characteristic calculation of the some parameters using a magnetic equivalent circuit method to verify a basic design result of a rotary-typed small-scaled linear induction motor for a railway transit. In a LIM, it is possible to express the parameters of the magnetic equivalent circuit into a function of the shape of the secondary aluminium plate and the airgap between the LIM primary core and the secondary aluminium plate. It means that the LIM properties can be changed considerably by the shape of the secondary aluminium plate and the airgap between the LIM primary core and the secondary aluminium plate. So, authors analyzed a tendency of changes of the magnetic equivalent circuit parameters and the LIM characteristics by changing of the airgap, the thickness of the secondary aluminium plate and the overhang length and shape of a rotary-typed small-scaled LIM, and accomplished a basic research to develop a real-scaled LIM for a railway transit.

• International Journal of Railway
• /
• v.1 no.1
• /
• pp.6-11
• /
• 2008

This paper presents a performance characteristic analysis methodology for a linear induction motor used for a lightweight train. In general, an analytical method cannot provide accurate results in a linear motor because of large airgap, end effect, transverse edge effect, 3-dimensional configurations, large leakage, and so on. Besides, a numerical method requires lots of memory and solving time for transient analysis. However, the suggested methodology which is a kind of hybrid solution with an analytical method and a numerical method is very fast and accurate. Based on the methodology, 3-D FEM analyses for various design schemes of the secondary reaction plate have been done and from the analysis results, the best configuration for an urban railway transit is chosen.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.49-54
• /
• 2005

Linear metro with single sided linear induction motor is applied to the urban transit system because of non adhesion drive. But linear induction motor is required to reduce the energy consumption to maximize efficiency of LIM. In this paper, design requirements such as pole pitch, motor length, air gap, overhang length and the material of secondary sheet are investigated as major parameter of SLIM. It is effective for increasing the efficiency to adopt the copper reaction plate and decrease the mechanical air gap as small as possible.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.44-48
• /
• 2005

In general, the parallel-connected linear induction motors(LIM) are fed by one VVVF inverter in the magnetically levitated vehicle(MAGLEV) or linear motor subway drives. The air gap length of the parallel-connected linear induction motors operating at a grade or curved sections can be different each other. The air gap difference of the two motors attached to the same module causes unequal phase currents, asymmetic thrust and attraction force generation. In this paper, parellel-connected linear induction motors are operated by one IGBT inverter under the different air gap condition so that the phase current characteristics are examined experimentally.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.4
• /
• pp.561-566
• /
• 2016

In this paper, effective design method of linear induction motor(LIM) for Maglev is proposed in order to maximize system efficiency of Maglev. For the high system efficiency of Maglev, it is important to minimize weight of traction motor. Light weight design by changing materials of core and winding is conducted without changing volume of LIM. For the silicon steel core of primary part for magnetic flux path, iron-cobalt alloy steel with high magnetic saturation characteristic compared to silicon steel is suggested. Moreover, aluminium winding with light weight instead of copper winding is wounded in the widen slot area due to the high magnetic saturation level. For the verification of performance of proposed model, the characteristics are analyzed by using finite element method(FEM).

• Journal of Electrical Engineering and Technology
• /
• v.7 no.2
• /
• pp.200-206
• /
• 2012

In order to develop a deep-underground great train express (GTX) in South Korea, the specifications decision and development of a traction control system (including an inverter and a traction motor), which considers a variety of route conditions, must be advanced. In this study, we examined the running resistance properties of a high-speed traction system based on a variety of tunnel types and vehicle organization methods. Then, we studied the power requirements necessary for the traction motor to maintain balanced speed in the high-speed traction system. From this, we determined the design criteria for the development of a high-speed traction system for use in the deep-underground GTX. Finally, we designed a linear induction motor (LIM) for a propulsion system, and we used the finite element method (FEM) to analyze its performance as it travelled through deep-underground tunnels.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.1
• /
• pp.65-72
• /
• 2016

This paper presents the analysis of the analysis of thrust characteristics of linear induction motors(LIMs) according to secondary reaction plate. LIMs are well known as high speed transport systems, which can obtain thrust directly without gears and links, or auxiliary mechanisms. A simple structure, easy maintenance, and less environmental pollution are advantages of LIMs. In transport systems using LIMs, the secondary reaction plate is an important design factor, because it has considerable impact on the cost of the railway as well as the performance of the LIMs. This paper deals analyzed the characteristics of linear induction motor used for moving the vehicle of container scanner. Thrust, efficiency and load characteristic were interpreted with FEM regarding two models whose material of secondary reaction plate was copper and aluminum. It suggested the interpretation of thrust, efficiency and power factor characteristic along slip and compared the operation ability of linear induction motor through characteristics analysis along the load.

• Proceedings of the KIEE Conference
• /
• 2004.10a
• /
• pp.9-11
• /
• 2004

This paper presents a position control system for a linear induction motor(LIM) with cage-type secondary using direct thrust control(DTC). The position controller, that combines the merits of integral-proportional(IP) speed control, is designed for the LIM. The actual position of the LIM is defected by the linear scale the resolution of 100. Thrust correction coefficient due to the end effect of the LIM is utilized in estimating actual thrust. As a result, responses of the position, speed, thrust, and flux are shown.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.47-49
• /
• 1996

The equivalent circuit of LIM is generally composed as the same that of rotary induction motor. However it is very difficult to move the LIM at synchronous velocity for open-secondary circuit test. The resistance representing the core losses in the primary core can not be ignored because the air-gap of LIM is larger than that of rotary induction motor. In this paper, the T-type equivalent circuit of a LIM with the core loss resistance is chosen using static zero slip test and theoritical analysis.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.1
• /
• pp.46-51
• /
• 2018

Constant slip frequency control has been conventionally used in thrust control of the linear induction motor(LIM) for magnetically levitated train. However in this paper variable slip frequency control method is presented to increase LIM efficiency according to change of driving notch. Thrust, attractive force, input power to inverter, regenerative power of the LIM are analyzed by finite element method when the train runs according to the presented control method. As a result it is proved experimentally that the electrical energy to inverter is reduced than the conventional method.