• 전기의세계
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• 제19권3호
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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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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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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• 제20권4호
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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.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권1호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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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.

• 한국전자통신학회논문지
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• 제8권2호
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• pp.285-290
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• 2013

Slotless 선형 동기 전동기(Linear Synchronous Motor)는 가동자의 구조가 간단하고 1차측 철심의 슬롯을 제거하여 갭 중의 자기에너지를 균일화해 추력 변동을 억제할 수 있는 장점을 가지고 있다. 또한 고효율로 구동이 가능하고 제어성이 타 선형 전동기에 비해 뛰어나 반송장치의 적용이 확대 되고 있는 실정이다. 하지만 주거 환경 분야의 적용은 미흡한 실정이다. 따라서 본 논문에서는 Slotless 선형 동기 전동기의 주거 환경 분야 적용을 위해 위치 피드백 제어에 따른 구동 특성을 고찰하고 속도 진동의 최소화와 안정된 응답 특성을 얻기 위해 부하 탑재와 가속도를 변화시켜 위치 피드백 제어를 비교함으로써 제어기의 유용함을 입증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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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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• 제2권2호
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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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• 제9권2호
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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.