• Title/Summary/Keyword: Magnet Circuit

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Study on Hybrid type Optical Pickup Actuator for Tilt Control (틸트제어를 위한 하이브리드형 광픽업 구동기에 대한 연구)

  • Kim, Chul-Jin;Lee, Kyung-Taek;Shin, Chang-Hun;Park, No-Cheol;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.782-787
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    • 2002
  • In optical disk drives (ODD), the demands of high data density and high speed have been increasing rapidly to achieve high data capacity and data transfer rate. The short wavelength laser, High NA objective lens, and high track following performance are needed to raise data density and data rate. For high-performance actuator, the improvement of linearity and acceleration become more important. Also, 3-axis actuator for active tilt compensation is introduced to overcome the decrease in disk tilt tolerance which is induced by short wavelength laser. In this paper, a hybrid type 3-axis actuator is presented and a new yoke structure, which can reduce the interaction between yoke and moving magnet, is designed to keep the efficiency of magnetic circuit. Experimental results show the validity of the yoke in the hybrid type actuator.

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Design and Analysis of a Linear Motor for Slim-line ODD (소형 광디스크 드라이브용 선형 구동기의 설계 및 특성 해석)

  • Shim, Min-Taek;Park, Joon-Hyuk;Baek, Yoon Su
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.794-798
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    • 2002
  • This paper deals with a moving coil type linear motor for fast access of the miniature ODD. This slim-line motor is composed of the mover supported by guide mechanism, the coil wound into it, and the yoke attached to the permanent magnet for stator. The driving force is generated by the PM of the stator and the current in the coils of the mover. Magnetic circuit analysis and Finite Element Method are applied to estimate the thrust force at air gap. In order to compare the force characteristics between two methods, various experiment results are applied to verify on a prototype. Also the flexible modes of the motor are predicted through the FEM and the structural components are modified to locate this on high frequency region.

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Design of the Linear Propulsion System of a High-Speed Dynamic Tester for Catenary-Current Collection (전차선로-집전계 주행시험기용 리니어 추진시스템 설계)

  • Kwon, Sam-Young;Lee, Ju
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.8
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    • pp.63-70
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    • 2006
  • This paper presents design of the linear propulsion system of a high-speed (200km/h) dynamic tester for catenary-current collection. Among various propulsion systems, a permanent magnet linear synchronous motor is chosen for need of high acceleration force. The design is performed by the equivalent magnetic circuit method and verified by the finite element method. In addition, analysis of the main effects of various design variables for performance of the propulsion system has been done by using simulation-based DOE method.

A Study of Double Type Transverse Flux Linear Motor for Improvement of Attraction force and Power Density (흡인력 저감과 추력밀도 향상을 위한 Double Type 횡자속 전동기에 대한 연구)

  • Hong Jung-Pyo;Chang Jung-Hwan;Kang Do-Hyun;Kim Young-Jung;Lee Ji-Young
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.3
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    • pp.120-126
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    • 2005
  • This paper deals with a Double-type Transverse Flux Linear Motor which can be applied to high power system. This type can reduce overall system volume because it has a double flux path, and less number of phases and turns comparing with prototype for one phase. This machine is based on permanent magnet excitation, and the pole shape is designed to reduce attraction force between stator and mover poles. In the paper, the basic configuration of double type is introduced first, and the principle of movement is explained. After performing the characteristic analysis by 3-dimensional equivalent magnetic circuit network, the results are discussed.

Reduction of Armature Reaction for Moving Coil Linear Oscillatory Actuator (가동코일형 LOA에서의 전기자 반작용 저감법)

  • Jang, S.M.;Jeong, S.S.;Lee, S.H.;Yun, I.K.
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.580-582
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    • 2001
  • In moving coil LOA, the variation of mover position and the consequent changes of coil flux path affect the coil inductance because of unbalanced magnetic circuit. Furthermore, the armature field shifts and distorts the airgap flux density distribution due to the magnet alone by a certain amount, which cause the unbalanced reciprocating force. In this paper, we propose the reduction method of armature reaction and coil inductance. The proposed LOA has the shorted ring the saturated core, the double coil, and Halbach array.

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Study on Design of Cone-Shaped Magnetic Bearing Spindle System for High Speed Internal Grinding (고속 내면 연삭기 주축용 원추형 자기베어링 설계 연구)

  • 노승국;경진호;박종권;최언돈;양승준;이재응;김남용;이동주
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.79-83
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    • 2001
  • A cone-shaped active magnetic bearing spindle system for high speed internal grinding is designed and tested. The cone-shaped AMB system consists of only 4 couples of magnet, it can be smaller and lighter than conventional radial-axial-type AMB system. In this paper, the cone-shaped electromagnets are designed by magnetic circuit theory, and de-coupled direct feedback PID controller is applied to control the coupled magnetic bearings. The designed cone-shaped AMB spindle system is built and constructed with a digital control system, and tested its stbility and dynamic performances. As the results of the tests, this spindle runs up to 40,000 rpm with about 5 ${\mu}{\textrm}{m}$ of runout, and the AMB system provides high damping ratio eliminating overshoot and resonance speed.

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A Study on Design, Fabrication Techniques and Test Results of 1.2kV 180A Inductive Superconducting Fault Current Limiter by Conduction-Cooled System (전도냉각에 의한 1.2 KV/80 A급 유도형 고온초전도 한류기의 설계, 제작 및 테스트에 관한 연구)

  • 강형구;전우용;이승제;안민철;배덕권;윤용수;고태국
    • Progress in Superconductivity and Cryogenics
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    • v.5 no.2
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    • pp.30-35
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    • 2003
  • The inductive superconducting fault current limiter (SFCLJ limits the fault current with its dc reactor. To fabricate the optimal dc reactor for inductive SFCL, several design and manufacturing technologies are necessary. In this paper, the manufacturing technology for dc reactor and cryogenic cooling method are described in detail. GM-cryocooler was used enlarge the critical current of dc reactor by cooling down the temperature of dc reactor about 20 K. Moreover, the results of short circuit test were described. Finally, the thermal characteristics of conduction-cooled system were discussed and then, sub-cooled nitrogen system was proposed to enhance the thermal stability of dc reactor.

Improvement of Current Controller Characteristics of Interior Permanent Magnet Synchronous Motor for Electric Vehicle (전기자동차용 매입형 영구자석 동기전동기의 전류제어기 특성 개선)

  • Park, Jung-Woo;Kim, Jong-Moo;Ku, Dae-Hyun;Kim, Heung-Geun
    • Proceedings of the KIEE Conference
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    • 1999.07f
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    • pp.2526-2528
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    • 1999
  • Parameters of equivalent circuit of IPMSM are varied according to current magnitude and current phase angle. Especially, Parameter variation of IPMSM for an electric vehicle(EV) is critical. Because current magnitude is very large. and current phase angle range also is wide. So, variation characteristics of $L_d$ and $L_q$ of the IPMSM are analyzed and verified through experiments. And then new parameter estimator of $L_d$ and $L_q$ that is constructed by neural network technique is suggested Using numerical method, the advanced characteristics of current controller of vector control algorithm is verified.

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Dynamic Analysis of a 3-Axis Ultra-Slim Actuator for Optical Disc Drives (광디스크 드라이브용 3축 초박형 액추에이터의 동특성 분석)

  • Kim Se-Won;Cho Tae-Min;Lee Ju-Hyung;Jin Kyoung-Bog;Rim Kyung-Hwa
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.4 s.235
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    • pp.624-631
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    • 2005
  • A note-book PC has become thinner in recent years, which requires the optical disc drives with small height and high memory capacity. Therefore the actuator of optical disc drives must be thinner and have disc tilt compensation function for high density memory. In this paper, the actuator with hybrid type is investigated for 3-axis ultra-slim actuator. A 3-axis ultra-slim actuator is designed by using the modal analysis of the actuator and the electromagnetic analysis of magnetic circuit to achieve dynamic characteristics. Also, magnetic force between tilt magnet and tilt yoke is investigated to and the influence on the DC sensitivity in the focus and track directions.

A Miniature Air-Bearing Positioning Stage with a Magnet-Moving Linear Motor (영구자석 이동형 선형 모터를 가진 초소형 공기베어링 스테이지)

  • Ro, Seung-Kook;Park, Jong-Kweon
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.8 s.197
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    • pp.89-96
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    • 2007
  • In this paper, a new air bearing stage with magnetic preload and a linear motor has been developed for the small precision machine systems. The new air bearing stage is unique in the sense that permanent magnets attached bottom of the iron core of table are used not only for preloading air bearings in vertical direction but also for generating thrust force by current of the coil at base. The characteristics of air bearings using porous pads were analyzed with numerical method, and the magnetic circuit model was derived for linear motor for calculating required preload force and thrust force. A prototype of single axis miniature stage with size of $120(W){\times}120(L){\times}50(H)\;mm^3$ was designed and fabricated and examined its performances, vertical stiffness, load capacity, thrust force and positioning resolution.