• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2012년도 전기공동학술대회 논문집
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• pp.121-122
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• 2012

In this research, we studied on improvement of the attraction force of solenoid operated valve for normal operation in harsh environment like vessel. Attraction force of the solenoid valves is effected by the B-H characteristics of magnetic material and the size of coil. In order to specify impact of the affection, we performed the B-H characteristics test and attraction force. Test results show that magnetic flux densities of the materials are difference each other more than 2 times in same magnetic intensity, and attraction force of the solenoid valve is 1.7 times difference as changes of resistance and the number of coil winding of solenoid.

• 전기학회논문지
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• 제57권9호
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• pp.1624-1627
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• 2008

This paper deals with a linear matrix inequality (LMI) approach to the design of a PID controller for an attraction type magnetic levitation system. First, we convert the $H_ {\infty}$ PID controller problem into a static output feedback problem. We then solve the static output problem by using the recently developed penalty function method. Numerical experiments show the effectiveness of the proposed algorithm.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.41-47
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• 2009

본 논문에서는 자기부상 시스템에서 널리 채용되고 있는 흡인식 자기부상 시스템의 제어특성을 개선하기 위한 연구를 수행하였다. 흡인식 자기부상 시스템은 그 특성 상 제어계의 불안정성을 내재하고 있기 때문에 일반적으로 산업현장에서 널리 사용되는 비례적분제어방식(PI)이 아닌 비례적분미분제어방식(PID)을 이용하여 제어 시스템을 구성한다. 본 논문에서는 이러한 PID 제어방식의 제어특성을 개선하기 위하여 외란관측자를 이용한 제어기를 제안 하였으며 컴퓨터 시뮬레이션과 실험을 통하여 그 특성을 확인하였다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권4호
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• pp.317-323
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• 2005

To increase the operating speed of the solenoid actuator, this paper proposed a modified model using a non-magnetic ring, which is welded on the magnetic guide tube, and also presents the characteristic equations, results of Finite Element Method (FEM) analysis for magnetic flux distribution and density in magnetic flux paths, and computer simulation results for the dynamic characteristics of plunger motion according to the stroke and time variation. As well, we proved the non-magnetic ring effect by experiments using prototypes.

• 한국자기학회지
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• 제6권1호
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• pp.40-47
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• 1996

본 논문에서는 영전식 magnetic lifter의 최적 설계 방법을 제시하였다. 등가 자기회로법으로 흡착시와 탈착시의 자장 해석 및 전자역 계산을 행하였고, 최적 설계를 위해 등가 자기회로법으로 해석된 흡착시의 전자력을 최대로 하는 lifter의 치수를 구하였다. 또한 흡착시의 전자력을 제한 조건으로 하여 lifter 전체의 부피를 최소로 하는 치수를 찾았다. 위 최적 설계를 위한 최적화 알고리즘으로는 (1+1) Evolution Strategy(ES)를 이용하였다. 또한 상용 자장해석 프로그램(MAXWELL)을 사용하여 얻은 결과와 위의 최적화 결과를 비교하여 본 논문의 최적화방법의 타당성을 검증하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.699-703
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• 1991

A magnetic levitation system with hybrid magnets, which is composed of permanent magnets and electromagnets, consumes less power than the conventional attraction type system. In this paper, we propose PID controller and PID-Fuzzy controller for hybrid magnet. We first present "constant gap" control technology with PID controller. Secondly, "zero power" control technology with PID-Fuzzy hybrid controller is presented.roller is presented.

• 한국기계가공학회지
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• 제15권2호
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• pp.89-96
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• 2016

Growing concerns regarding environmental pollution have increased the demand for green vehicles. Green vehicles include electric vehicles, compressed natural gas vehicles, fuel cell vehicles, and vehicles running on fuels such as bio diesel or an ethanol blend. CNG vehicles are equipped with a cylinder valve installed in a high-pressure vessel to control the CNG flow. For this purpose, the optimum design of cylinder valve solenoid is necessary to secure at driving a CNG vehicle. In this study, electromagnetic field analysis to ensure the reliable operation of the solenoid was conducted by using a Maxwell V15. The electromagnetic field analysis was performed by magnetostatic technique according to distance between magnetic poles in order to predict the attraction force. Finally, the attraction force was validated through comparison between the Maxwell results and the measurement results. From the results, the error of attraction force was found to be 2.85 N to 6.5 N under the testing conditions.

• 대한기계학회논문집A
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• 제30권10호
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• pp.1202-1208
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• 2006

This paper presents an experimental characteristics of electro-hydraulic proportional pressure control valve. In this study, poppet and valve body which are assembled into the proportional solenoid were designed and manufactured. The constant force characteristics of proportional solenoid actuator in the control region should be independent of the plunger position in order to be used to control the valve position in the fluid flow control system. The stroke-force characteristics of the proportional solenoid actuator is determined by the shape (or parameters) of the control cone. In this paper, steady state and transient characteristics of the solenoid actuator for electro-hydraulic proportional valve are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attraction force in the control region independently on the stroke position. The effects of the parameters such as control cone length, thickness and taper length are also discussed.

• 한국분말재료학회지
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• 제30권4호
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• pp.297-304
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• 2023

Iron oxide (Fe₂O₃) nanoclusters exhibit significant potential in the biomedical and pharmaceutical fields due to their strong magnetic properties, stability in solutions, and compatibility with living systems. They excel in magnetic separation processes, displaying high responsiveness to external magnetic fields. In contrast to conventional Fe2O3 nanoparticles that can aggregate in aqueous solutions due to their ferrimagnetic properties, these nanoclusters, composed of multiple nanoparticles, maintain their magnetic traits even when scaled to hundreds of nanometers. In this study, we develop a simple method using solvothermal synthesis to precisely control the size of nanoclusters. By adjusting precursor materials and reducing agents, we successfully control the particle sizes within the range of 90 to 420 nm. Our study not only enhances the understanding of nanocluster creation but also offers ways to improve their properties for applications such as magnetic separation. This is supported by our experimental results highlighting their size-dependent magnetic response in water. This study has the potential to advance both the knowledge and practical utilization of Fe₂O₃ nanoclusters in various applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.110-113
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• 1991

An electromagnet is one of the important devices in magnetic levitation system. Its weight takes large part in the total weight of a vehicle. That is the reason why it is important to design the electromagnet optimally to maximize the attraction force with constant volume. This study presents the optimum value of the design variables which can produce the maximal attraction force under constant magnet volume. For this, non-linear programming in optimization technique is used. And to confirm reliability of the results, the optimally designed electromagnet is analyzed by FEM. The attraction force of the optimally designed electromagnet is increased maximally 72% compared with that of the basic model. And the results obtained by non-linear programming has 30% error compared with that of FEM.