• 융복합기술연구소 논문집
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• 제7권2호
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• pp.1-5
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• 2017

The rotating electrodynamic wheel over a conductive plate produces thrust force as well as normal force. Specially, separating the conductive plate and spacing apart each part, the lateral stability of the rotating wheel is guaranteed due to the restoring force into neutral position. In this paper, the force characteristics of the electrodynamic wheel rotating over the conductive plate is analyzed using the finite element tool. First, the dominant parameters are identified considering the geometric configuration and the operating condition. And the sensitivity for the parameter deviation is quantified for the high force density. The above topology can be applied as an actuating principle for inter-city train as well as contact-free transfer device.

• 제어로봇시스템학회논문지
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• 제17권9호
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• pp.882-887
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• 2011

A spiral electrodynamic wheel is proposed as an actuator for the contactless conveyance of a conductive rod. When rotating the wheel around the rod, a radial force, a tangential force, and an axial force are generated on the rod and cause a screw motion of the rod. The rotation of the rod is the inevitable result due to traction torque of the wheel and the unintended motion to be excluded. However, the rotating speed of the rod should be measured without mechanical contact to be cancelled out through the controller, so the electrodynamic wheel is used as a sensor measuring the rotating speed of the rod indirectly as well as an actuator. In this paper, we model the magnetic forces by the proposed wheel theoretically and compare the derived model with simulation result by Maxwell, and analyze influences on the magnetic forces by key parameters constituting the wheel. The feasibility of the conveyance system is verified experimentally.

• 한국생산제조학회지
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• 제20권3호
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• pp.251-256
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• 2011

Instead of multi-phase ac current, the magnetic field travels spatially through mechanical rotation of permanent magnets at the electrodynamic wheel (EDW). Traveling of magnetic field generally leads to a generation of inductive force in the traveling direction. In this paper, we suggest a spiral EDW to travel the magnetic field in the axial direction of the conductive rod. So, it is possible to levitate and transfer the rod through multi-axial forces by the spiral EDW. However, physical dimensions of permanent magnets constituting EDW influence relative ratios between three-axial forces generated on the rod. Therefore, the sensitivity analysis for design parameters is performed using FEM analysis. The stable operation is verified experimentally.

• 한국산학기술학회논문지
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• 제17권3호
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• pp.310-316
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• 2016

도전성 평판에 부분적으로 걸쳐 회전하는 축형 동전기 휠을 구동원으로 이용하는 비접촉 반송 시스템을 제안한다. 회전하는 동전기 휠에는 3축력이 발생되는데 이 중 중력방향 힘과 횡방향 힘은 자기안정성을 갖고 있으므로 공간상에서 반송 시스템의 동적 안정성을 확보하기 위해서는 길이 방향 힘만을 제어하는 것으로 충분하다. 동전기 휠은 원주 방향을 따라 주기적으로 반복되는 극성을 갖는 영구자석으로 구성되어있으므로 기본 극의 기하학적 형상이나 극수 등은 안정성 여유에 큰 영향을 미친다. 또한 휠과 전도판간의 중첩된 영역 역시 횡방향으로의 강성을 결정하는 주요 인자이므로 본 논문에서는 안정성을 성능 지표로 휠을 구성하는 주요 설계 변수에 대한 민감도 해석을 수행한다. 얻어진 설계 값을 이용하여 제작된 시스템으로 휠을 포함하는 이동 개체의 수동적인 안정성을 실험적으로 검증한다.

• 소음진동
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• 제10권4호
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• pp.615-622
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• 2000

Discharge valve mechanism for an electrodynamic-oscillating compressor is different from that of a conventional reciprocating compressor. It has a larger discharge port area, heavier valve mass and stiffer valve spring comparing with the reciprocating one. Since the motion of piston is not kinematically restricted as in conventional reciprocating compressors, the stroke of the piston can change sensitively with supplied boltage and load. Thus piston can impact with discharge valve occasionally. This work deals on dynamic analysis of discharge valve considering all of those different characteristics. Impact is considered by a spring-mass model, and the pressure fluctuation at the both sides of the valve is also included considering the discharge port area and valve spring preload. It is assumed that piston moves in the region of between top and bottom dead center not by calculating piston motion from an electrodynamic equation but by getting values through experiment. Discharge pressure fluctuation is calculated using Helmholtz modeling. Finally, dynamic model for a discharge valve is constructed. In order to validate the model analysis results, the valve motion is experimentally measured and compared with analysis.

• 한국초전도ㆍ저온공학회논문지
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• 제11권1호
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• pp.49-54
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• 2009

This paper presents the numerical simulation results on the moving type electrodynamic suspension (EDS) simulator and static type EDS simulator using high-Tc superconducting (HTS) levitation magnet. The levitation force of the EDS system is formed by the reaction between the moving magnet and the fixed ground conductor. The possible two ways to simulate the EDS system were simulated in this paper by using finite element method (FEM). The first way was the moving type simulator which consists of the fixed HTS magnet and the moving ground conductor. The second way was the static type simulator which consists of the fixed magnet, the fixed ground conductor and the ac current supply system. To verify the characteristics of high speed EDS system with the moving type simulator heavy, large and fast moving ground conductor is needed. The static type simulator can get the characteristics of the high speed EDS system by applying equivalent ac current to velocity, therefore it does not need large moving part. The static type EDS simulator, which can consist of an HTS magnet, the fixed ground conductor(s), an AC power supply and the measuring devices, also test the effect of the shape of the ground conductor easily. The plate type ground conductor made stronger levitation force than ring type ground conductor. Although the outer diameter 335 mm ring type ground conductor (Ring3) was larger than the outer diameter 235 mm ground conductor (Ring2), the levitation force by Ring2 was stronger than that by Ring3. From the calculation results on this paper, the consideration of the magnetic flux distribution according to the levitation height should be included in the process of the ground conductor design.

• 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.198-200
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• 2009

This paper presents the numerical simulation results on the moving type electrodynamic suspension (EDS) simulator. Superconducting EDS system is generated by the interaction between the magnetic field made by the induced the eddy current in the ground conductor and the moving magnetic field made by onboard superconducting magnet. The levitation force of EDS system, which is proportional to the strength of the moving magnetic field, becomes saturated according to the increase of the velocity Especially, the levitation force is influenced by the structure of HTS magnet and ground conductor. The 3-D numerical analysis with FEM was used to find the distribution of the magnetic field, the optimal coil structure, and the calculation of the levitation force.

• 한국자기학회지
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• 제4권2호
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• pp.106-113
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• 1994

초전도 반발식 자기부상열차의 동특성을 해석하기 위하여 외력에 의하여 대차가 기울어진 경우에 차량에 가해지는 전자력을 계산하였다. 집중부하방식의 열차에 있어서 크게 나타나는 단부효과 를 고려하기 위하여 공극자속의 형태에 대한 가정없이 자속분포를 계산하였으며, 대차의 옆질(roll), 뒷질(pitch) 및 편주(yaw)시의 전자력특성과 복원토오크를 검토하였다. 6개의 초전도자석이 탑재된 대 차가 차량의 양쪽에 설치된 열차에 대해서 계산한 결과, 토오크의 방향은 차량을 안정하게 하는 방향 으로 나타나서 본 자기부상시스템은 기본적으로 안정한 시스템임을 보여주고 있다.

• 한국입자에어로졸학회지
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• 제19권3호
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• pp.63-76
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• 2023

An electrostatic precipitator (ESP) has a low pressure drop and a high collection efficiency but its collection efficiency can be reduced due to dust accumulation on the collection plates during long-term operations. In order to maintain the initial dust collection efficiency, it is necessary to periodically clean the collection plates. The common cleaning methods are using physical impacts or water sprays. These cleaning methods can lead to damage to the collection plate or generate wastewater. Herein, we implemented an electrodynamic screen (EDS) for ESP cleaning and evaluated its surface cleaning performance of particles. The EDS is an electrostatic system that can electrostatically repel particles on surfaces, allowing it to clean the ESP without causing damage and wastewater generation. Our evaluation included the analysis of the effects of AC voltage characteristics, electrode configuration and environmental conditions on the cleaning performance of the EDS with the aim of achieving effective surface cleaning. It has been demonstrated that activating the EDS cleans up to 65% of the particles on the surface, which indicates about 94% of our target cleaning zone.