• 전기의세계
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• v.19 no.3
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• pp.1-9
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• 1970

In this paper, the equation for the generated force is introduced, on the basis of Maxwell's electromagnetic equation, by dividing the air-gap magnetic field into the region of the constant amplitude and the region of the pulsating field in the both ends of iron core, in the case that the typical 3 phase winding is employed in the double sided 3 phase linear induction motor with sheet rotor in accrodance with the winding method of rotary induction machine. With the effect of the overhang region being taken into account, the result, in which the equation is established, inducates that theoretical values nearly coincides with the measured values in the interval of slip s=0-0.8.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.172-174
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• 2008

The detent force of the permanent magnet linear synchronous motor (PMLSM) is caused by the interaction between the permanent magnet and the iron core of the mover without input current. It is a function of the mover position relative to the stator. This paper proposes a control based method to reduce the detent force for the PMLSM. This detent force that can be predicted by finite element method (FEM) is compensated by injecting the instantaneous current using the field oriented control (FOC) method. Both the simulated and experimental results are reported to validate the effectiveness of this proposed method.

• Journal of Magnetics
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• v.20 no.4
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• pp.444-449
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• 2015

Soft magnetic composites (SMCs) are especially suitable for the construction of low-cost, high-performance motors with 3-D magnetic fields. The main advantages of SMCs is that the iron particles are insulated by the surface coating and adhesive used for composite bonding, the eddy-current loss is much lower than that in laminated steels, especially at higher frequencies, and the hysteresis loss becomes the dominant component of core losses. These properties enable machines to operate at higher frequencies, resulting in reduced machine size and weight. In this paper, 3-D topologies are proposed that enable the application of SMCs to effectively reduce losses in high-speed permanent magnet (PM) motors. In addition, the electromagnetic field characteristics of the motor topologies are evaluated and compared using a non-linear finite element method (FEM) based on 3-D numerical analysis, and the feasibility of the motor designs is validated.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.1
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• pp.19-26
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• 1999

A moving-coil-type linear motor, designed and fabricated, is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The interaction between permanent magmet and armature fie1d, so called "push/pull effect", is to shift the airgap flux density variation due to the magnet alone by a certain amount. Thrust therefore is shift downward or upward. The push/pull effect was presented through the FEM analysis and the static tests. We compared the thrust obtained through the FEM analysis with the static tests. Finally, we present the linearity and correction coefficients of the thrust in consideration of the push/pull effects.l effects.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.85-87
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• 2001

Linear motor damper(LMD) for vibration control of structure is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The active mass of LMD is 1.5 ton and consisted of permanent magnet and iron yoke. In this paper, LMD system is manufactured and tested for dynamic characteristics and frequency response.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.2
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• pp.285-290
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• 2013

The slotless linear synchronous motor(LSM) has the advantages that the structure of the mover is simple and it can control the trust force ripple by make the magnetic energy in a gap uniform by removing a slot of the primary iron core. Also, the application of the transportation system is becoming expansion because it high efficiency drive is possible and compares with the other LSM as control is more excellent. However, the application of the living field was unsatisfactory. Therefore, in this study, we examined the drive characteristics by the position feedback control for the living field application of the slotless LSM and we prove useful of the controller through load loading and the acceleration changing to get minimization of the speed vibration and stable answer characteristics.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.973.1_974.1
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• 2009

One of the most important technical improvement required for ropeless elevator system to become practical is the improvements in overall system efficiency. Moreover, the predominant drawback of permanent magnet (PM) linear synchronous motor (LSM) is large detent force. Therefore, for the given volume the selection of high power density PM-LSM with low detent force is very imperative. In this paper, we will investigate the characteristics of thrust and detent force of PM-LSM under different motor topology structure. Finally, the long stator double-sided iron core type PM-LSM with fractional slot winding is the best choice for the ropeless elevator system.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.880-882
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• 2001

A moving-coil-type linear oscillatory actuator is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The inductance of moving coil and the push/pull effect is obtained from the permeance model of LOA with the open magnetic circuit. The analytical method are verified using the 2D finite element method.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.208-215
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• 2007

The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic effects are analyzed and modeled using the complex state-variable approach. To minimize the force ripple and realize the high precision control, the components of force ripples are extracted first and then compensated by injecting the instantaneous current to counteract the force ripples. And this method of the PMLSM system is realized by the field oriented control method. In order to verify the validity of this proposed method, the system simulations are carried out and the results are analyzed. The effectiveness of the proposed force ripples reduction method can be seen according to the comparison between the compensation and non-compensation cases.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.514-522
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• 2014

A new type of high precision electromagnetic suspension (EMS) which can support heavy tray along long stroke rail is proposed in this paper. Compared with the conventional EMS, the suggested moving-core typed EMS has the levitation electromagnets (EMs) on the fixed rail. This scheme has high load capability caused by iron-core and enables simple tray structure. Also it does not have precision degradation caused by heat generation from EMs, which is a drawback of conventional EMS. With these merits, the proposed EMS can be an optimal contactless linear bearing in next generation flat panel display (FPD) manufacturing process if the ability of long stroke movement is proved. So a special Section Switching Algorithm (SSA) is derived from the resultant force and moment equations of the levitated tray which enables long stroke movement of the tray. In order to verify the feasibility of the suggested SSA, a simple test-setup of the EMS with 2 Section-changes is made up and servo-controlled in the simulation and experiment. The simulation shows the perfect changeover the EMs, and the experiment shows overall control performance of under ${\pm}40{\mu}m$ gap deviations. These results reveal that the newly suggested contactless linear bearing can simultaneously achieve high load capability and precision gap control as well as long stroke.