• 한국정밀공학회지
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• 제19권6호
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• pp.184-191
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• 2002

This paper presents the thermal behavior of a synchronous linear motor with high speed and force. Such a linear motor can successfully replace ball lead screw in machine tools because it has a high velocity, acceleration and good positioning accuracy. On the other hand, low efficiency and high heating up during operation are disadvantage of linear motors. For the application of linear motors to machine tools a water-cooling system is often used. In this research, structure of the linear motor and water cooler is changed to improve the thermal behavior of the linear motor. Some important effects of an integrated cooler, an U-cooler and a thermally symmetrical cooler are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.141-143
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• 2008

Due to the demand for high-output motors in the limited space between the wheels in an electric train, self-ventilating traction motors have been used for many years. periodical disassembly maintenance is necessary to remove the small quantities of dust that enter the motor from the open-air ventilation. Reducing this burden, as well as increasing efficiency and reducing noise, would benefit the next generation of moters To address these needs, KRRI is developing a fully enclosed type traction motor, a fully enclosed type traction motor with outer fans, a high-efficiency permanent-magnet synchronous motor and a direct-drive motor(DDM) as traction motors for the next generation of trains.

• 한국정밀공학회지
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• 제19권7호
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• pp.163-170
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• 2002

This paper presents some measures far the optimization of the thermal behavior of linear motors, which are used as a high speed feed mechanism in machine tools. Thermo-Sandwich-Construction using two cooling circuits and an insulation layer shows an effective cooling system for linear motors. Conducting sheet can be also used to reduce heat flow from linear motor to machine table. Cooling pipe is a simple and effective cooling system for the secondary part of synchronous linear motor. Through the combination of the Thermo-Sandwich-Construction, conducting sheet and cooling pipe the thermally optimized linear motor shows a well improved thermal behavior in comparison with the prototype motor.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.118-123
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• 2013

This paper presents performance comparison between concentrated winding and distributed winding of IPMSM (Interior Permanent Magnet Synchronous Motors) which is recently used for light-weight railway applications. Motors are designed on various schemes and analyzed by using FEM (Finite Element Method) instead of EMCNM (Equivalent Magnetic Circuit Network Method) in order to take into account saturation and non-linear magnetic property. The overall performance such as torque, torque ripple, losses, demagnetization, efficiency, power density and so on are investigated in detail at the rated and maximum operating speed. The results of the analysis found that both concentrated and distributed winding IPMSMs are promising candidates for high power railway traction motor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.621-625
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• 1996

The feed system of the machine tools is limited by the mechanical transmission elements. However, thanks to the advanced modern technology, those machines are able to equip with linear motors. In this paper, the types and application aspects of linear motor are discussed and a synchronous type of the linear motors has been applied to X-Y table for machining center. The performance shows an outstanding result in terms of the accuracy, speed and stiffness. Machine tool system with linear motors is expected to be more productive machines using linear motor in the near next years.

• Journal of Magnetics
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• 제21권1호
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• pp.72-77
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• 2016

Although the initial cost of permanent-magnet linear synchronous motors is high owing to the installation of armatures over the full length of the transportation lines, linear motors are useful for transportation systems because of their high speed, acceleration, and deceleration. For these reasons, research into reducing the cost of linear motors is necessary, and a stationary distributed-armature system has been suggested for installing armatures in sections where acceleration and deceleration of the mover are required. However, each armature has ends that significantly increase the cogging force, resulting in the increase in the thrust ripple of the mover. Therefore, in order to improve the thrust ripple of the system, the present study aims to provide auxiliary teeth on both ends of the armature to achieve an optimal design through an analysis of the contribution ratio with respect to factors regarding the design of the experiment and the objective function.

• 한국정밀공학회지
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• 제27권6호
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• pp.39-46
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• 2010

Linear induction motor is adopted as an actuator of the planar stage. An inherently poor characteristic at zero or ultra-low speed zone of the induction motor is remarkably improved due to a recent development of power electronic semiconductor technology and a spatial vector control theory. At present, a servo response speed of the induction motor reaches 90 percent of one of PM synchronous or BLDC motor. Specially, as a secondary of the induction motor can be constructed using uniform conducting sheets, there is no periodic force ripple as in PM motors. So, the induction motor can be superior to another driving means under a certain condition. This paper discusses the overall development procedure of non-contact planar stage with a big workspace using linear induction motors.

• Journal of Power Electronics
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• 제19권3호
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• pp.794-802
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• 2019

Magnetic geared motors are driven using the same operating principle as conventional synchronous motors in which a magnetic gear is embedded. The magnetic geared motor is structurally similar to a magnetic gear. However, by applying currents to the stator coil, the high-speed rotor is rotated by a magnetic field and the low-speed rotor is rotated according to the gear ratio. In this paper, the operational principle of a magnetic geared motor and the magnetic flux density in its inner and outer air gaps are described. Then the magnetic flux density in the two air gaps is used to express a method for calculating the electrical and mechanical output. Results obtained with the analytical calculation method are compared with those of the finite element analysis. Finally, a prototype is used to verify the results of the analytical calculation and FEA.

• 대한기계학회논문집A
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• 제25권12호
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• pp.2078-2090
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• 2001

This paper deals with a precise position synchronous control by a cooperative control method of two axes rotating systems. First, the system's dynamics including motor drives described by a motor circuit equation and Newton's kinetic formulation about rotating system. Next, based on conventional PID(Proportional, Integral, Derivative) control law, current and speed controller are designed very simply to follow up reference speed correctly under some disturbances. Also, position synchronous controller designed to minimize position errors according to integration of speed errors between two motors. Then, the proposed control enables the distributed drives by a software control algorithm to behave in a way as if they are mechanically hard coupled in axes. Further, the stabilities and robustness or the proposed system are investigated. Finally, the proposed system presented here is shown to be more precise position synchronous motion than conventional systems through some simulations and experiments.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.330-333
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• 2003

In this thesis. the application of the synchronizing control of the intelligent indoor lift system is showed. The separate axes of the indoor lift system are driven independently. PID controller, synchronous flexible logic compensating method and tilt sensor are applied to enhance the performance of the intelligent indoor lift system. the tilt sensor senses the horizontal error of the whole system. PID controller and synchronous flexible logic are used to compensate the synchronous errors of both the separate axes and whole system to be zero. Namely, using not the hardware coupling but the software algorithm. the indoor life system is operated without the error. Before applying the real system, the simulation using matlab testifies the possibility of the lift system. And the realization of the system is demonstrated with two DC servo motors. In the experiment test, flexible logic to compensate the synchronous error is chosen by the comparative method. the indoor lift system has to be considered the loading factor as the disturbance. Because the intelligent indoor lift system is developed to support the patients who don't change for themselves to move. finally, the system which considers the weight of the patient as the disturbance can carry the patients safely without synchronous and position error.