• 전기학회논문지
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• 제58권2호
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• pp.278-284
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• 2009

The global force and interaction body force density were evaluated in permanent magnets by using the virtual air-gap scheme incorporating the finite-element method. Until now, the virtual air-gap concept has been successfully applied to calculate a contact force and a body force density in soft magnetic materials. These force calculating methods have been called as generalized methods such as the generalized magnetic charge force density method, the generalized magnetizing current force density method, and the generalized Kelvin force density method. For permanent magnets, however, there have been few research works on a contact force and a force density field. Unlike the conventional force calculating methods resulting in surface force densities, the generalized methods are novel methods of evaluating body force density. These generalized methods yield the actual total force, but their distributions have an irregularity, which seems to be random distributions of body force density. Inside permanent magnets, however, a smooth pattern was obtained in the interaction body force density, which represents the interacting force field among magnetic materials. To evaluate the interaction body force density, the intrinsic force density should be withdrawn from the total force density. Several analysis models with permanent magnets were tested to verify the proposed methods evaluating the interaction body force density and the contact force, in which the permanent magnet contacts with a soft magnetic material.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.83-85
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• 2007

This paper presents the vibration reduction of PMLSM according to permanent magnet array. The detent force and the lateral force arc generating the thrust ripple that cause vibration in PMLSM. The detent force, the thrust and the lateral force is analyzed by 3D FEM. And the acceleration sensor is used for experimentation of vibration.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.201-203
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• 1997

As electromagnetic systems have the complexity and high performance, they should be designed to take into account the vibration, noise and strain of mechanical aspect as well as electrical problems. Until now, mechanical approaches have been tried to analyze the subject, but it is difficult to figure out the matter in mechanical consideration. Because they are mainly related to electromagnetic phenomena. This paper deals with the theories and numerical formulations of magnetic force density. Several methods are applied to an actuator and DC machine model to calculate magnetic force density. These results are compared with the total force obtained by maxwell stress tensor and virtual work principle.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1216-1228
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• 2016

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.104-106
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• 1996

In this paper, the dynamic motion driven by electromagnetic force of transformer windings is modeled and its characteristics are numerically analyzed. The electromagnetic field is obtained using the 2D finite element method taking account of anisotropic property of iron core, and the electromagnetic force on the transformer winding is calculated from Lorenz's force formula using the field distribution result. The system motion equation driven by electromagnetic force and gravitational force is numerically analyzed using the 4-order Runge-Kutta algorithm. Above analyses procedure is applied to a single-phase core-type transformer to validate its algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.80-82
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• 2006

본 논문에서는 영구자석의 스큐형상에 따른 영구자석형 선형 동기기(PMLSM: Permanent Magnet Linear Synchronous Motor)의 제반 특성을 해석하였다. 단방향 Skew의 경우 스큐 방향과 직각 방향으로 작용하는 Lateral Force가 존재한다. 이러한 Lateral Force는 가동자와 LM 가이드 사이에 마찰력으로 작용하여 PMLSM의 제반 특성을 저하시킨다. Lateral Force의 저감을 위하여 영구자석을 V형상으로 모델링하여 단방향 착자 시의 특성과 비교하였다. V-skew 모델의 lateral force가 단방항 skew 모델의 lateral force의 11.3[%]로 감소하는 양호한 결과를 얻었다.

• Journal of Electrical Engineering and Technology
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• 제3권4호
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• pp.584-592
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• 2008

In this paper, we propose a new model of the magnetic control force exerted on the levitation object in magnetic levitation systems. The model assumes that the magnetic force is a function of the voltage applied to an electromagnet and the position of a levitation object. The function is not explicitly expressed but represented through a 2D lookup table constructed from the experimentally measured data. Unlike the conventional model that reveals only local characteristics of the magnetic force, the proposed model shows global characteristics satisfactorily. Specially devised measurement equipment is utilized in order to gather the data required for model construction. An experimental procedure to construct the model is presented. We apply the proposed model to designing a sliding mode controller for a lab-built magnetic system. The validity of the proposed model is illustrated by comparing the performances of the controller adopting the conventional model with that of the controller adopting the proposed model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.990-993
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• 1988

RMFC (Resolved Motion Force Control) is the method to control the Cartesian force and position using FCC (Force Convergent Control) instead of the complicated dynamic equations of the manipulator. The gain parameters of the controller are adjusted through many trial and errors. In this paper PD-optimal control method is introduced to give optimal gain parameters which minimize the difference between actural acceleration and desired acceleration. To show the validitiesn of the proposed method computer simulations are performed for the two-link manipulator.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.307-314
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• 2018

In this paper, analytical modeling of lift and drag forces in permanent magnet electrodynamic suspension systems (PM EDSs) are presented. After studying the impacts of PM dimensions on the permanent magnetic field and developed lift force, it is indicated that there is an optimum PM length in a specified thickness for a maximum lift force. Therefore, the optimum PM length for achieving maximum lift force is obtained. Afterward, an objective design optimization is proposed to increase the lift force and to decrease the material cost of the system by using Genetic Algorithm. The results confirm that the required values of the lift force can be achieved; while, reducing the system material cost. Finite Element Analysis (FEA) and experimental tests are carried out to evaluate the effectiveness of the PM EDS system model and the proposed optimization method. Finally, a number of design guidelines are extracted.

• 전기학회논문지
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• 제63권10호
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• pp.1473-1478
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• 2014

This paper deals with design and thrust force measurement of EMS type LSM for propulsion of the high-speed maglev train. The load of maglev train is calculated, and the design equations of the LSM are presented, and the LSM which is suitable for the operation of short-distance test track is designed. In addition, the finite element analysis is performed to confirm the back-EMF and thrust force characteristics of the LSM designed model. A short length LSM prototype model is manufactured. Finally, the thrust force of the LSM is measured by the method applying dc current to the stator winding instead of three-phase ac current. And the validity of the design and analysis is verified by this measurement.