• Title/Summary/Keyword: Rare-earth magnet

Search Result 114, Processing Time 0.029 seconds

Breakage and Surface Oxidation Characteristics of Waste NdFeB Magnet for Recycling (NdFeB 자석 재활용을 위한 파분쇄 및 그에 따른 표면 산화 특성 연구)

  • Kim, Kwanho;Kim, Gahee;Lee, Hoon;Kang, Jungshin
    • Resources Recycling
    • /
    • v.28 no.3
    • /
    • pp.26-34
    • /
    • 2019
  • Due to the increasing demand of rare earth magnet for various application, it is predicted that the amount of waste rare earth magnet will increase sharply. The process of waste rare earth magnet recycling is mainly consisted of leaching and separation of rare earth element contained in the magnet. However, there is no study on the breakage characteristics of the waste rare earth magnet for production of magnet powder. Therefore, in this study, effective crushing/grinding process and breakage characteristics were investigated for waste rare earth magnet. In the case of jaw crusher, the particle size of magnet was effectively reduced without rapid oxidation. In ball mill grinding test, it was found that the grinding process was not performed properly at the early stage of grinding. Moreover, waste rare earth magnet showed very low specific rate of breakage(S) and high fraction of fine particle breakage distribution(B) compared to ordinary minerals. These results can be used as a basic data for developing crushing/grinding circuit of waste rare earth magnet.

A Study for Replacement of Rare-earth Perment Magnets: Exchange Spring Magnets (희토류 대체 영구자석의 연구동향: 교환 스프링자석)

  • Hong, Ji-Sang
    • Journal of the Korean Magnetics Society
    • /
    • v.22 no.5
    • /
    • pp.188-193
    • /
    • 2012
  • Permanent magnet is one of the most important parts in modern industry and the rare earth elements play an essential role for operation of permanent magnet. As is well known, the rare earth elements are mostly produced in China and the world is now facing serious problems owing to supply and demand imbalances. Many attempts have been performed to replace these rare-earth based permanent magnets by rare-earth free magnets, but they have not been successful so far. Regarding this issue, we discuss about an exchange spring magnet as a potential rare earth free permanent magnet structure.

Effect of Addition Elements on the Production of the 2-17 Type High Performance of the Rare Earth Permanent Magnet Materials by the Reduction and Diffusion Process (환원·확산법에 의한 2-17형 고성능 희토류영구자석 재료의 제조에 있어서 첨가원소의 영향)

  • Song, Chang-Been;Cho, Tong-Rae
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.8 no.4
    • /
    • pp.333-339
    • /
    • 1995
  • The reduction and diffusion process(R-D process) is an economical way to produce the functional materials which contain rare-earth elements and has been applied to the production of rare-earth magnet meterials($SmCo_5$, $Nd_{15}Fe_{77}B_8$), magneto-optical(MO) target materials and hydrogen storage alloy, etc. However, because of difficult to control of the final composition, the R-D process has not been applied to production of the 2-17 type rare earth permanent magnet materials which contain several elements. Therefore, this work was as a basic study for the production of the 2-17 type rare earth permanent materials with composition $Sm(Co_{0.72}Fe_{0.21}Cu_{0.05}Zr_{0.03})_{7.9}$ by the R-D process, the following were mainy examined ; the amount of metallic calcium as a reductant, homogenization condition of the alloy after the R-D reaction, masuring of magnetic properties of the sample after step aging. The sample prepared by the R-D process contained a little more oxygen than that prepared by the melting method, however, showed almost the same magnetic properties.

  • PDF

A Study on the Design of BLDC Motor Replacing Ferrite Magnet with Rare Earth Magnet (페라이트 자석을 희토류 자식으로 교체한 BLDC 전동기의 설계에 관한 연구)

  • Chung, Tae-Kyung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.22 no.4
    • /
    • pp.121-129
    • /
    • 2008
  • This paper deals with the design of BLDC motor replacing ferrite magnet with rare earth magnet. Electric machinery system using ferrite magnet motor is already widespread in large numbers. Electrical appliance makers have a tendency to adhere to existing system using ferrite magnet motors because of redesigning the whole system. This paper designs the rare earth magnet motor untouching the external system dimension and motor outer size. To do the design simply, finite element package is used iteratively To reduce the cogging torque effect and magnetic saturation, stator yoke shape and the groove of the end face of yoke are redesigned.

Improvement of Demagnetization by Rotor Structure of IPMSM with Dy-free Rare-Earth Magnet

  • Imamura, Keigo;Sanada, Masayuki;Morimoto, Shigeo;Inoue, Yukinori
    • Journal of international Conference on Electrical Machines and Systems
    • /
    • v.2 no.2
    • /
    • pp.141-147
    • /
    • 2013
  • Permanent magnet (PM) motors that employ rare-earth magnets containing dysprosium (Dy) are used in electric and hybrid electric vehicles. However, it is desirable to reduce the amount of Dy used since it is expensive. This study investigates the rotor structure of a PM synchronous motor with a Dy-free rare-earth magnet. Flux barrier shapes and PM thicknesses that enhance the irreversible demagnetization are investigated. In addition, a rotor structure that improves the irreversible demagnetization is proposed. We demonstrate that the proposed rotor structure without Dy improves the irreversible demagnetization.

Modeling of Switched Reluctance Motor (SRM) Drive and Control System using Rotor Position Information Sensor (회전자 위치정보 센서를 이용한 Switched Reluctance Motor (SRM)의 구동 및 제어 시스템 Modeling)

  • Jeong, Sungin
    • The Journal of the Institute of Internet, Broadcasting and Communication
    • /
    • v.21 no.3
    • /
    • pp.137-142
    • /
    • 2021
  • In recent years, permanent magnets such as IPM (Interior Permanent Magnet) motors or SPM (Surface Permanent Magnet) motors that can obtain high efficiency and power density by inserting rare earth permanent magnets into the rotor are used. Research on the used electric motor is being actively conducted. Since it uses a permanent magnet, it has the advantage of high efficiency and high power density compared to reluctance motors and induction motors, but by inserting a permanent magnet into the rotor, it operates at high speeds and decreases reliability due to demagnetization of the permanent magnets, and increases the cost of rare earth metals. In this paper, in accordance with the development of future technology that can replace rare-earth permanent magnet motors and technological preoccupation of rare-earth reduction type motors and de-rare-earth motors, switched reluctance motors that do not require permanent magnets (Switched Reluvtance Motors) Motor, SRM) to drive driving control. Using the 3-phase SRM library provided by the PSIM simulation program, we will study the driving and control system modeling of SRM using the rotor position information sensor.

An Optimal Design of BLDC Motor Using Rare Earth Magnet By Niching Genetic Algorithm (Niching 유전 알고리즘을 이용한 희토류 자석 BLDC 모터의 최적설계)

  • Chung, Byung-Ho;Chung, Tae-Kyung;Jin, Yang-Sun
    • Proceedings of the KIEE Conference
    • /
    • 2000.07b
    • /
    • pp.717-719
    • /
    • 2000
  • In this paper, we discussed an optimal design of BLDC motor using rare earth magnet. In motor design using rare earth magnet, because of the characteristics that rare earth magnets have high remanence, the effect of saturation of steel has to be considered. For this, we used nonlinear finite clement method. For optimal design, a Niching genetic algorithm is used. As a result, we found out a set of BLDC motor shapes increasing motor efficiency, and decreasing cogging torque.

  • PDF

Optimal Design of Interior Permanent Magnet Synchronous Machines Consideration of Magnet BH Characteristic with Different Rotor Type using Response Surface Methodology (반응표면분석법을 이용한 영구자석의 형상 및 특성에 따른 매입형 영구자석 동기기의 최적 설계)

  • Im, Young-Hun;Jang, Seok-Myoung
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.62 no.8
    • /
    • pp.1080-1089
    • /
    • 2013
  • Interior Permanent Magnet Synchronous Machines (IPMSMs) with rare earth magnet are widely used in electric vehicles and hybrid electric vehicles. IPMSMs having high efficiency, high torque, and a wide speed range are employed in propulsion system. And the rotor in an IPMSM is generally made of a rare earth magnet to achieve a large energy product and high torque. This paper discusses issues regarding design and performance of IPMSMs using different factors of BH magnetic characteristic. It is necessary to choose factors of magnetic material according to permanent magnet shape in rotor for high performance. Response Surface Methodology (RSM) is selected to obtain factors of magnetic material according to variety of rotor shapes. The RSM is a collection of mathematical and statistical techniques useful for the analysis of problems in which a response of interest in influenced by several variables and the objective is to optimize response. Therefore, it is necessary to analyze the torque characteristics of an IPMSM having magnet BH hysteresis curve with different rotor shape. Factors of residual flux density (Br) factor and intrinsic coercive force (Hc) are important parameters in RSM for rotor shape. The rotor shapes for IPMSMs having magnet BH characteristic were investigated using the RSM, and three shapes were analyzed in detail using FEA. The results lead to design consequence of IPMSMs in the various rare earth magnet materials.

Design of Fan-shape Type PMSM for Improving Efficiency of Non-rare Earth Motor (비희토류 전동기의 효율 향상을 위한 Fan-shape type PMSM 설계 및 성능 분석)

  • Cho, Sooyoung;Ahn, Hanwoong;Ham, Sang-Hwan;Jin, Chang-Sung;Lee, Sung Gu;Lee, Ju
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.65 no.2
    • /
    • pp.360-364
    • /
    • 2016
  • The rare earth output is concentrated in limited number of countries including China. Also the necessity for development of non-rare earth motor is getting signified due to the rapid increase of rare earth price and resource weaponizing policies. Non-rare earth motor is generally designed as spoke type PMSM (Permanent Magnet Synchronous Motor) in order to maximize the power density. Such spoke type PMSM has advantage in concentrating the flux but demonstrates lower efficiency compared to permanent magnet using Nd (Neodymium) permanent magnet. Therefore, applications with strong necessity for efficiency need rotor structure having improved efficiency compared to spoke type PMSM. Hence, this study suggested fan-shape type PMSM with somewhat lower power density but maximized efficiency. Fan-shape type PMSM is a rotor shape demonstrating outstanding reduction of iron loss compared to existing spoke type. Thus, this study analyzed the improvement of efficiency and reduction of loss arising from the suggested shape through parameter calculation.

Current Status and Research Trend of Rare-earth Permanent Magnet (희토류 영구자석의 현황 및 개발 동향)

  • NamKung, Seok;Cho, Sang-Geun;Kim, JinBae
    • Journal of the Korean Magnetics Society
    • /
    • v.22 no.6
    • /
    • pp.221-227
    • /
    • 2012
  • High performance permanent magnets have become the subject of considerable attention because of the potential applications in the traction motors of hybrid and electric vehicles and wind generators. Nd-Fe-B magnets have attracted considerable interest due to a large maximum energy product. However, Nd-Fe-B magnet cannot be used in high temperature (${\sim}200^{\circ}C$) applications due to the thermal degradation of coercivity. Therefore, the development of high coercivity Nd-Fe-B permanent magnet is a challenging issue. In case of high coercivity Nd-Fe-B permanent magnet, an increment in the intrinsic coercivity can be easily achieved by substituting Nd atoms with Dy or Tb atoms. However, these heavy rare-earth elements are known to cause a decrease in remanence due to the antiferromagnetic coupling between Dy and Fe atoms. In addition, Dy is relatively expensive and being limited in quantity. Hence, a new technology that can increase the coercivity of Nd-Fe-B sintered magnet using only a small amount, or even, no amount of heavy rare-earth elements is being investigated. This article describes the research trend in reducing the heavy rare-earth elements in Nd-Fe-B magnets.