전자석 바이어스 Diskless반경방향-축방향 일체형 자기 베어링 해석

나언주(Na, Uhn-Joo) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.10

The theory for a new electromagnetically biased diskless combined radial and axial magnetic bearing is developed. A typical magnetic bearing system is composed of two radial magnetic bearings and an axial magnetic bearing. The axial magnetic bearing with a large axial disk usually limits rotor dynamic performance and makes assembling and disassembling difficult for maintenance work. This paper proposes a novel electromagnet biased integrated radial-axial magnetic bearing without axial disk. This integrated magnetic bearing uses two axial coils to provide the bias flux to the radial and axial air gaps of the combined bearing. The axial magnetic bearing unit in this combined magnetic bearing utilizes reluctance forces developed in the non-uniform air gaps such that the axial disk can be removed from the bearing unit. The 4-pole homopolar type radial magnetic bearing unit is also designed and analyzed. Three dimensional finite element model for the bearing is also developed and analyzed to illustrate the diskless combined magnetic bearing.

Design and Analysis of a New Permanent Magnet Biased Integrated Radial-Axial Magnetic Bearing

나언주 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

A typical magnetic bearing system is composed of two radial magnetic bearings and an axial magnetic bearing. The axial magnetic bearing with a large axial disk usually limits rotor dynamic performance and makes assembling and disassembling difficult for maintenance work. This paper proposes a novel permanent magnet biased integrated radial-axial magnetic bearing without axial disk. The axial magnetic bearing unit in this integrated magnetic bearing utilizes reluctance forces such that the axial disk can be removed from the bearing unit. The 4-pole homopolar type radial magnetic bearing unit is also designed and analyzed. 3-D flux analysis is provided to illustrate the novel diskless integrated magnetic bearing.

자기부상용 Halbach 자석 배열을 이용한 선형 능동자기 베어링의 최적설계

이학준(Hakjun Lee),안다훈(Dahoon Ahn) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.1

본 논문은 Halbach 자석 배열을 사용하여 새로운 구조의 선형 능동자기 베어링 개발을 제시하고자 하였다. 선형 능동자기 베어링은 자석 간 발생하는 자중 보상 능력과 코일에 전류를 인가함으로서 발생하는 동적 힘을 이용하여 반도체 장비, 가공 장비 등 다양한 산업분야에서 적용되고 있다. 기존의 선형 능동자기 베어링은 크기에 비해 동적 힘이 낮은 문제점이 있다. 따라서 본 논문에서는 기존 보다 높은 동적 힘을 발휘하는 선형 능동자기 베어링을 개발하기 위해 시뮬레이션을 통해 기존 구조를 분석하고 새로운 구조를 제안하였다. 제안된 새로운 구조의 선형 능동 자기베어링을 최적화하기 위해서 모델링 및 최적 설계를 수행하였다. Sequential Quadratic Programming을 사용하여 제안된 선형 능동자기 베어링의 기하학적 설계 변수에 대해 최적의 설계가 수행되었으며, 최적설계 된 선형 능동자기 베어링의 설계성능은 정적 힘 45.063 N, 로렌츠 힘 상수 19.543 N/A 로 기존보다 높은 동적 힘을 발휘하는 것이 확인되었다. This paper presents a new structure for a linear active magnetic bearing using a Halbach magnet array. The proposed magnetic bearing consisted of a Halbach magnet array, center magnet, and single coil. The proposed linear active magnetic bearing has a high dynamic force compared to the previous study. The high dynamic force could be obtained by varying the thickness of a horizontally magnetized magnet. The new structure of Halbach linear active magnetic bearing has a high dynamic force. Therefore, the proposed linear active magnetic bearing increased the bandwidth of the system. Magnetic modeling and optimal design of the new structure of the Halbach linear active magnetic bearing were performed. The optimal design was executed on the geometric parameters of the proposed linear active magnetic bearing using Sequential Quadratic Programming. The proposed linear active magnetic bearing had a static force of 45.06 N and a Lorentz force constant of 19.54 N/A, which is higher than previous research.

고속 회전체의 축방향 길이 최소화를 위한 자기베어링 설계 및 운전

박주홍,노수진,조한욱 대한전기학회 2024 전기학회논문지 Vol.73 No.2

In this study, a fork-type heteropolar(FHP) magnetic bearing is proposed as an innovative advancement in magnetic bearing technology. The FHP magnetic bearing enhances winding density within the slot by positioning bobbins, and housing paired windings, side by side. In addition, a comparative analysis was conducted against the conventional heteropolar(CHP) magnetic bearing. The design of the FHP magnetic bearing optimizes the width of the magnetic pole surface by aligning it with the axis direction, enabling maximum force generation. Mathematical modeling and Campbell diagram analysis were employed to quantify the reduction in axial space achieved by the FHP magnetic bearing. Finite element analysis was performed to examine force characteristics and experimental verification confirmed the stability of the FHP magnetic bearing. Additionally, the FHP magnetic bearing was applied to an oil-free refrigerant compressor, validating its practical viability in industrial applications.

A Four Pole, Double Plane, Permanent Magnet Biased Homopolar Magnetic Bearing with Fault-Tolerant Capability

Na, Uhn-Joo The Korean Society of Industry Convergence 2021 한국산업융합학회 논문집 Vol.24 No.6

This paper develops the theory for a novel fault-tolerant, permanent magnet biased, 4-active-pole, double plane, homopolar magnetic bearing. The Lagrange Multiplier optimization with equality constraints is utilized to calculate the optimal distribution matrices for the failed bearing. If any of the 4 coils fail, the remaining three coil currents change via a novel distribution matrix such that the same opposing pole, C-core type, control fluxes as those of the un-failed bearing are produced. Magnetic flux coupling in the magnetic bearing core and the optimal current distribution helps to produce the same c-core fluxes as those of unfailed bearing even if one coil suddenly fails. Thus the magnetic forces and the load capacity of the bearing remain invariant throughout the failure event. It is shown that the control fluxes to each active pole planes are successfully isolated. A numerical example is provided to illustrate the new theory.

Experimental Studies of Magnetic Fluid Seals and Their Influence on Rolling Bearings

Marcin Szcz?ch 한국자기학회 2020 Journal of Magnetics Vol.25 No.1

There are many seals designed for rolling bearings. One interesting perspective is the application of magnetic fluid seals for this purpose, because they are an alternative to commonly-used solutions and combine the advantages of contactless seals (e.g. labyrinths) and contact seals (e.g. rubber lip seals), therefore they have low resistance moment and high tightness. This publication describes rolling bearings and a magnetic fluid seal system in terms of the maximum sealing pressure, which was compared to the results of numerical simulations, and the influence of the magnetic field on the bearing torque was also investigated. The tests were carried out for various types of seal stage shapes. Different magnetic circuit configurations have been considered i.e. the main magnetic flux passing through the seals or rolling bearings (steel or ceramic). Studies have shown that a magnetic field increases the torque in the bearing and magnetic fluid seals may reduce the torque because part of the magnetic flux passes through the seal elements. This result is important because it shows that it"s possible to reduce the negative effects of variable magnetic fields on rolling bearings by using additional elements of the magnetic circuit.

Design and Implementation of a Fault-Tolerant Magnetic Bearing System

Park, B.C.,Noh, M.D.,Ro, S.K.,Kyung, J.H.,Park, J.K. Korean Tribology Society 2003 KSTLE International Journal Vol.4 No.2

One of the obstacles for a magnetic bearing to be used in the wide range of industrial applications is the failure modes associated with magnetic bearings, which we don't expect for conventional passive bearings. These failure modes include electric power outage, power amplifier faults, position sensor faults, and the malfunction of controllers. Fault-tolerant magnetic bearing systems have been proposed so that the system can operate in spite of some faults in the system. In this paper, we designed a fault-tolerant magnetic bearing system for a turbo-molecular vacuum pump. The system can cope with the actuator/amplifier faults which are the most common faults in a magnetic bearing system. We implemented the existing fault-tolerant algorithms to experimentally prove the adequacy of the algorithms for industrial applications. As it turns out, the system can operate even with three simultaneously failing poles out of eight actuator poles.

Thrust Hybrid Magnetic Bearing using Axially Magnetized Ring Magnet

Cheol Hoon Park,Sang Kyu Choi,Ji Hoon Ahn,Sang Yong Ham,Soohyun Kim 한국자기학회 2013 Journal of Magnetics Vol.18 No.3

Hybrid-type magnetic bearings using both permanent magnets and electromagnets have been used for rotating machinery. In the case of conventional thrust hybrid magnetic bearings supporting axial loads, radially magnetized permanent ring magnets, which have several demerits such as difficult magnetization and assembly, have been used to generate bias flux. In this study, a novel thrust hybrid magnetic bearing using an axially magnetized permanent ring magnet is presented. Because it is easy to magnetize a ring magnet in the axial direction, the segmentation of the ring magnet for magnetization is not required and the assembly process can be simplified. For verifying the performance of the proposed method, a test rig that consists of a proposed thrust magnetic bearing and variable loads is constructed. This paper presents the detailed design procedures and the obtained experimental results. The results show that the developed thrust magnetic bearing has the potential to replace conventional thrust magnetic bearings.

소형 풍력 발전기의 발전 효율 향상을 위한 마그네틱 베어링 개발

조성원(Seongwon Jo),김은호(Eunho Kim),박진수(Jinsu Park),이재백(Jaebaek Lee),이준혁(Joonhyuk Lee),김송길(Songkil Kim) 대한기계학회 2022 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.10 No.1

본 논문에서는 영구자석을 이용하여 내륜과 외륜이 부상된 형태의 마그네틱 베어링을 설계하고, 시제품을 제작하여 마그네틱 베어링의 성능을 평가하였다. 설계된 마그네틱 베어링을 자체 제작한 소형 풍력 발전 시스템에 적용하여 마그네틱 베어링의 성능을 평가하였으며, 기계식 베어링을 이용한 소형 풍력 발전 시스템의 발전 성능과 비교하여 그 우수성을 증명하였다. 최대 풍속 5.5m/s에서 600rpm으로 축이 회전하여 10V 전압의 출력을 확인하였으며, 기계적 베어링을 사용한 경우 대비 대략 최대 2.5배 많은 전압이 출력되는 것을 확인하였다. 마그네틱 베어링은 소형 풍력 발전 시스템에서 마찰에 의한 에너지 손실을 최소화시켜 높은 발전 효율을 구현할 수 있을 것으로 기대되며, 뿐만 아니라 다양한 기계시스템에 적용되어 마찰에 의한 에너지 손실을 최소화할 것으로 기대된다. In this design, we developed a magnetic bearing with permanent magnets targeting to improve the electricity generation efficiency of a small wind turbine. The small wind turbine with two magnetic bearings yielded the output voltage of 10 V with a maximum wind speed of 5.5 m/s tested in the experiments, which was verified about 2.5 times higher than the output voltage when using mechanical ball bearings. It is expected that the developed magnetic bearing will reduce energy loss and improve the energy generation efficiency of a small wind turbine as well as can be utilized in various mechanical systems with minimizing energy loss.

소형 풍력 발전기의 발전 효율 향상을 위한 마그네틱 베어링 개발

조성원,김은호,박진수,이재백,이준혁,김송길 대한기계학회 2022 기술과 교육 Vol.10 No.1

In this design, we developed a magnetic bearing with permanent magnets targeting to improve the electricity generation efficiency of a small wind turbine. The small wind turbine with two magnetic bearings yielded the output voltage of 10 V with a maximum wind speed of 5.5 m/s tested in the experiments, which was verified about 2.5 times higher than the output voltage when using mechanical ball bearings. It is expected that the developed magnetic bearing will reduce energy loss and improve the energy generation efficiency of a small wind turbine as well as can be utilized in various mechanical systems with minimizing energy loss. 본 논문에서는 영구자석을 이용하여 내륜과 외륜이 부상된 형태의 마그네틱 베어링을 설계하고, 시제품을 제작하여 마그네틱 베어링의 성능을 평가하였다. 설계된 마그네틱 베어링을 자체 제작한 소형 풍력 발전 시스템에 적용하여 마그네틱 베어링의 성능을 평가하였으며, 기계식 베어링을 이용한 소형 풍력 발전 시스템의 발전 성능과 비교하여 그 우수성을 증명하였다. 최대 풍속 5.5m/s에서 600rpm으로 축이 회전하여 10V 전압의 출력을 확인하였으며, 기계적 베어링을 사용한 경우 대비 대략 최대 2.5배 많은 전압이 출력되는 것을 확인하였다. 마그네틱 베어링은 소형 풍력 발전 시스템에서 마찰에 의한 에너지 손실을 최소화시켜 높은 발전 효율을 구현할 수 있을 것으로 기대되며, 뿐만 아니라 다양한 기계 시스템에 적용되어 마찰에 의한 에너지 손실을 최소화할 것으로 기대된다.