parameters calculation,Time-stepping FEM

关键词:d-q axis cross-saturation,DDPMG,improved simulation

model,parameters calculation,Time-stepping FEM
摘要:In some control strategies of the direct-rive permanent

magnet generator(DDPMG),the mathematics model is excessively

simplified and some complex nonlinear characteristics,such as

core saturation and cross-saturation,are Ball Neodymium Magnets generally neglected.To

solve this problem,this paper utilizes the frozen element

permeability method to compute the armature self-and mutual-

inductance,permanent magnet d-and q-axis flux varying with d-axis

and q-axis current,then an improved model is presented in which

the core saturation and cross-saturation between d-axis and q-

axis are considered effectively.Based on this model,the method

for computing the performance of the generators is also

proposed.Taking a 1.5-MW DDPMG http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php as an example,the time-stepping

finite element method(T-S FEM) is adopted to analyze the

performance with no-load and loaded conditions,the results show a

good agreement with the ones obtained by the improved

model.Compared with the simplified model,it is demonstrated that

the presented model has the high efficiency and reliability and

can provide a good reference for optimization design of DDPMG and

other PM motors.

quantum tunneling,magnetic coupling

关键词:lanthanide,single-molecule magnets,relaxation

dynamics,quantum tunneling,magnetic coupling
摘要:In the area of molecular magnetism,single molecule magnets

(SMMs) containing lanthanide elements are of immense scientific

and technological interest because of Block neodymium magnet their large energy barriers

and high measured hysteresis temperature.Although there has been

significant progress in the synthesis and characterization of

lanthanide-based SMMs,there are still challenges,for instance,how

single-ion anisotropy of lanthanide elements can be exploited,and

how zero-field tunneling of http://www.chinamagnets.biz/Neodymium/Block-neodymium-magnet.php magnetization can be suppressed.This

article is devoted to the progress in various methodologies for

modulating magnetic relaxation,especially in terms of crystal

field and magnetic interactions.The crystal field plays a

dominant role in creating single-molecule magnets with largely

anisotropic f-elements,while the strong coupling between magnetic

centers is able to suppress quantum tunneling of magnetization

efficiently.

Nd-Fe-B magnet;;microstructure;;coercivity

作者:陈钟敏;王纳新;宋晓平;王笑天;
关键词:Nd-Fe-B magnet;;microstructure;;coercivity
单位:Department of Materials Science and Engineering Xi'an

Jiaotong University,Xi'an 710049,PRC,Neodymium Magnets
http://www.999magnet.com/products/110-sintered-neodymium-magnets Department of Materials

Science and Engineering,Xi'an Jiaotong University,Xi'an

710049,PRC,Department of Materials Science and Engineering,Xi'an

Jiaotong University,Xi'an 710049,PRC,Department of Materials

Science and Engineering,Xi'an Jiaotong University,Xi'an

710049,PRC,
摘要:<正> 1 IntroductionIt is well known that the microstructure

of Nd-Fe-B sintered magnets is primarilycomposed of a Nd_2Fe_

(14)B matrix,an intergranular Nd-rich phase and a small amount of

aB-rich phase.Additional phases may exist in the magnets due to

the introduction of oxy-gen in the process' of producing

magnets.Several researchers have reported some evi-dence about

the existence of the additional phases in the magnets and

supposed them tocontribute to coercivity by pinning the domain

walls in magnetization reversal.To getmore information about the

additional phases,we systematically studied the microstructure

compound, coercivity, microstructure

作者:杨俊;周寿增;张茂才;马德青;李佛标;王润;
关键词:NdFe_(10)Mo_2N_x compound, coercivity, microstructure.
单位:Department of Materials Science and Engineering  University

of Science and Technology of Beijing magnetic materials
http://www.999magnet.com Beijing 100083

PRC,Department of Materials Science and Engineering University of

Science and Technology of Beijing Beijing 100083 PRC,Department

of Materials Science and Engineering University of Science and

Technology of Beijing Beijing 100083 PRC,Department of Materials

Science and Engineering University of Science and Technology of

Beijing Beijing 100083 PRC,Department of Materials Science and

Engineering University of Science and Technology of Beijing

Beijing 100083 PRC,Department of Materials Science and

Engineering University of Science and Technology of Beijing

Beijing 100083 PRC,
摘要:<正> Great attention has been paid to the RFe_(11)(Ti, V)

compounds with ThMn_(12) type structure since 1987. Among them

the SmFe_(11)Ti compound seems to be the most promising candidate

for permanent magnets(PMs). However, the saturation magnetization

of SmFe_(11)Ti is much less than that of Nd_2Fe_(14)B although

its Curie temperature T_C is approximately the same as that of

Nd_2Fe_(14)B; in addition, Sm is more expensive than Nd. All this

makes SmFe_(11)Ti uncompetitive from economic point of view.

rare-earth permanent magnet, explosion sintering.

作者:许建民;胡伯平;饶晓雷;刘贵川;董晓琳;刘英烈;王德文;高景兰;曹飞

;王亦忠;宋琪;刘蕾;王震西;张登霞;蔡铭;李世海;李华;尹林;
关键词:rare-earth permanent magnet, explosion sintering.
单位:San Huan Research Laboratory  Academia Sinica P.O.Box 603

Beijing 10080 PRC,San Huan Research neodymium standard state
http://www.999magnet.com/products/112-neodymium-standard-state Laboratory Academia Sinica

P.O.Box 603 Beijing 10080 PRC,San Huan Research Laboratory

Academia Sinica P.O.Box 603 Beijing 10080 PRC,San Huan Research

Laboratory Academia Sinica P.O.Box 603 Beijing 10080 PRC,San Huan

Research Laboratory Academia Sinica P.O.Box 603 Beijing 10080

PRC,San Huan Research Laboratory Academia Sinica P.O.Box 603

Beijing 10080 PRC,San Huan Research Laboratory Academia Sinica

P.O.Box 603 Beijing 10080 PRC,San Huan Research Laboratory

Academia Sinica P.O.Box 603 Beijing 10080 PRC,San Huan Research

Laboratory Academia Sinica P.O.Box 603 Beijing 10080 PRC,San Huan

Research Laboratory Academia Sinica P.O.Box 603 Beijing 10080

PRC,San Huan Research Laboratory Academia Sinica P.O.Box 603

Beijing 10080 PRC,San Huan Research Laboratory Academia Sinica

P.O.Box 603 Beijing 10080 PRC,San Huan Research Laboratory

Academia Sinica P.O.Box 603 Beijing 10080 PRC,Institute of

Mechanics Academia Sinica Beijing 100080 PRC,Institute of

Mechanics Academia Sinica Beijing 100080 PRC,Institute of

Mechanics Academia Sinica Beijing 100080 PRC,Magnetism Laboratory

Institute of Physics P.O.Box 603 Beijing 100080 PRC,Magnetism

Laboratory Institute of Physics P.O.Box 603 Beijing 100080 PRC,
摘要:<正> Since the discovery of R_2Fe_(17)N_y by Coey and Sun

Hong, the intrinsic and extrinsic magnetic properties of these

nitrides have been extensively investigated. Having very good

intrinsic magnetic properties with Curie temperature of 749 K and

room temperature anisotropy field of 14 T superior to Nd_2Fe_

(14)B, and room temperature saturation magnetization of 1.5 T,

the Sm_2Fe_(17)N_y nitride is expected to become new permanent

magnet for application. The Sm_2Fe_(17)N_y nitride with intrinsic

coercivity of 3T has been obtained by mechanical alloying. The

Sm_2Fe_(17)N_y, magnets bonded by metal zinc have intrinsic

coercivity μ_(0i)H_c over 0.5 T and magnetic product (BH)_(max)

about 80 kJ·m~(-3)(10

rare-earth permanent magnet

作者:张绍英,戴礼智,李锋
关键词:Sm_2Fe_(17)N_(23), rare-earth permanent magnet,

coercivity, bonded magnet.
单位:Central Iron and Steel Research magnetic materials
http://www.999magnet.com Institute, Beijing 100081,

PRC





,Central Iron and Steel Research Institute, Beijing

100081, PRC





,Central Iron and Steel Research Institute,

Beijing 100081, PRC
摘要:<正> Although Nd-Fe-B alloys have the outstanding permanent

magnetic properties, their temperature stability and corrosion

resistance are poor. So a worldwide research for new high Curie

temperature and Fe-rich hard magnetic materials has been carried

out. Recently Coey

grain size;;nucleation

关键词:Pr-Fe-B magnet;;coercivity;;grain size;;nucleation;;cast-hot press
摘要:<正> Characteristics of magnetic hardening in cast-hot pressed magnet Pr_(19)Fe_(74.5)B_5Cu_(1.5)were stu-died.The neodymium price
http://www.999magnet.com/products/142-neodymium-price microstructure features and virgin magnetization curve reveal a nucleation control-led coercivity mechanism.Regression analysis shows that the intrinsic coercivity variesinversely as the logarithm of the average grain size:_iH_c(MA/m)=1.7312-0.48161nd(μm)which confirms the randomness of nucleation of reversed domains and the statistical nature ofcoercivity,indicating that the decrease of grain size would reduce the average number of de-fects on its surface and lower the probability of magnetization reversal of a grain and the cu-mulative fraction of the grains that have reversed their magnetization.Coercivity is thus en-hanced.

impure Nd-Fe-B magnets

作者:连法增;任建军;艾禄;张效时;赵恒和;
关键词:low cost;;impure Nd-Fe-B magnets;;thermal stability
单位:Northeast University of Technology Shenyang 110006,China,Shenyang Permanent Magnetic Materials Factory,Shenyang,110015,China,Northeast University of Technology,Shenyang 110006,China,Northeast neodymium standard state
http://www.999magnet.com/products/112-neodymium-standard-state University of Technology,Shenyang 110006,China,Northeast University of Technology,Shenyang 110006,China,
摘要:<正> 1.IntroductionSince the Nd-Fe-B magnets appearedin 1983,researchers,producers and users ofthe permanent magnetic materials have paidgreat attention to them.Because the mag-nets have low Curie temperature Tc andbad thermal stability as well as easeoxidation,their applications are limited insome fields.The researchers are greatly in-terested in increase energy product

Compound permanent magnet synchronous machine

关键词:Compound permanent magnet synchronous machine (CPMSM), Operating characteristic, Three-dimensional finite element analysis, Cogging torque, Direct-drive pumping unit
摘要:We propose a novel kind of neodymium standard state
http://www.999magnet.com/products/112-neodymium-standard-state compound permanent magnet synchronous machine (CPMSM), which is applicable in low-speed and high-torque situations. We first explain the structure of the CPMSM. Based on theoretically deducing the calculation formulae of the CPMSM electromagnetic parameters, we analyze the operating characteristics of the CPMSM, and obtain the power-angle curves and working curves. The no-load magnetic field distribution and the cogging torque are analyzed by applying the finite element method of three-dimensional (3D) magnetic fields, to determine the no-load leakage coefficient and the waveform of the cogging torque. Furthermore, the optimal parameters of the permanent magnet for reducing the cogging torque are determined. An important application target of the CPMSM is in directdrive pumping units. We have installed and tested a direct- drive pumping unit in an existing oil well. Test results show that the power consumption of the direct-drive pumping unit driven by CPMSM is 61.1% of that of the beam-pumping unit, and that the floor space and weight are only 50% of those of a beam-pumping unit. The noise output does not exceed 58 dB in a range of 1 m around the machine when the machine is 1.5 m from the ground.

metal materials; NdFeB magnet; strip casting

作者:李波,胡季帆,王东玲,郭炳麟,王新林
关键词:metal materials; NdFeB magnet; strip casting; hydrogen decreipitation; nucleation mechanism; rare earths
单位:Department of Functional Materials, Central Iron & Steel Research Institute,Department   of Physics, Block neodymium magnet
http://www.chinamagnets.biz/Neodymium/Block-neodymium-magnet.php Shandong University,Department of Functional Materials, Central Iron & Steel Research Institute,Department of Functional Materials, Central Iron & Steel Research Institute,Department of Functional Materials, Central Iron & Steel Research Institute  Beijing 100081, China









, Jinan 250100,  China









, Beijing 100081, China









, Beijing 100081, China









, Beijing 100081, China
摘要:The coercivity mechanism of Nd  Fe  B magnets prepared by combination of strip  casting with hydrogen decrepitation techniques was investigated. The microstructure of (Nd    0.935  Dy    0.065  )    14.5  Fe    79.4  B    6.1   magnet was observed. The average grain size is about 6～12 μm. The magnetizing field dependence of the hardmagnetic properties for the (Nd    0.935  Dy    0.065  )    14.5  Fe    79.4  B    6.1   and the temperature dependence of the coercivity for the Nd    14.5  Fe    79.4  B    6.1   were investigated. Results show that the coercivity for magnets  prepared by the combination of strip  casting with hydrogen decrepitation techniques is controlled by the nucleation mechanism.

rare earths; hydrogen decrepitation; NdFeB; permanent m

作者:张正义;肖耀福;裘宝琴;董明;
关键词:NdFeB bonded magnets;;Magnetic properties;;HDDR process
单位:University of Science and Technology Beijing Beijing 100083,China,University of Science and Technology Beijing,Ball Neodymium Magnets
http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php Beijing 100083,China,University of Science and Technology Beijing,Beijing 100083,China,University of Science and Technology Beijing,Beijing 100083,China,
摘要:<正> The present paper describes the effect of alloy composition,homogenization anddehy-drogenization procedures on magnetic properties of NdFeB type of HDDR powders and the bondedmagnet.The results showed that the powders prepared by HDDR process possesses useful magnetic proper-ties and a better thermal stability than the sintered NdFeB magnet does.


作者:刘丽敏,李长江,张国忠
关键词:Rare earths, Rare earth permanent magnet, Pulse laser, Laser drilling
摘要:ＳｔｕｄｙｏｎＬａｓｅｒＤｒｉｌｉｎｇｉｎＲａｒｅＥａｒｔｈＭａｇｎｅｔｓＬｉｕＬｉｍｉｎ（刘丽敏），ＬｉＣｈａｎｇｊｉａｎｇ（李长江）（ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＣｈｅｍｉｃａｌＴｅｃｈｎｏｌｏｇｙ，Ｂｅｉｊｉｎｇ１０００２９，Ｃｈｉｎ...


作者:姜忠良









,陈秀云









,陈晓东









,石大立









,杨昌平









,朱静
关键词:rare earths; hydrogen decrepitation; NdFeB; permanent magnet
摘要:The effect of Hydrogen Decrepitation (HD) process on the magnetic properties and microstructure of sintered NdFeAlB magnet (HD magnet) was investigated. The results show that the coercivity of HD magnet is higher than that of traditional ball milling (BM) magnet, while the remanence and the maximum energy product of HD magnet are lower. Microstructure analysis shows that some fine un  sintered powders are distributed at the grain boundaries of HD magnet. X  ray diffraction (XRD) analysis reveals that the degree of easy axis alignment of HD magnet is lower. Some ideas to improve the current HD process were proposed.

nanocrystalline permanent

作者:郑波;赵素芬;
关键词:nanocrystalline permanent

magnets;coercivity;micromagnetics;finite element method;rare

earths
单位:Department of Physics, Beihang University;
摘要:Magnetization configurations were calculated under various

magnetic fields for nanocrystalline magnetic materials Pr-Fe-B permanent magnets by

micromagnetic finite element method.According to the

configurations during demagnetization process, the mechanism of

magnetization reversal was http://www.999magnet.com analyzed.For the Pr2Fe14B with 10 nm

grains or its composite with 10vol.% α-Fe, the coercivity was

determined by nucleation of reversed domain that took place at

grain boundaries.However, for Pr2Fe14B with 30 nm grains,

coercivity was controlled by pinning of the nucle-ated domain.For

Pr2Fe14B/α-Fe with 30vol.% α-Fe, the demagnetization behavior

was characterized by continuous reversal of α-Fe moment.

彭龙;杨青慧;刘颖力;宋远强;张怀武;

作者:彭龙;杨青慧;刘颖力;宋远强;张怀武;
关键词:rare earth permanent magnets; Sm(Co, Fe, Cu, Zr)Z; PPM

focusing system; Maxwell 2D/3D; magnetic field simulation
单位:State Key Laboratory of Electronic Thin Films and Integrated

Devices, University of Electronic Science and Technology of

China;
摘要:Rare earth permanent magnets neodymium standard state Sm(Co, Fe, Cu, Zr)Z with

outstanding performance and high-temperature thermal stability

were fabricated. Optimized by Fe content and process, Sm

(Co0.72Fe0.15Cu0.1Zr0.03)7.5 magnet with Br>0.75 T and Hci>1300

kA/m at 300 °C can be obtained. According to the performance

data of Sm(Co0.72Fe0.15Cu0.1Zr0.03)7.5, the magnetic field along

central axis BZ in periodic http://www.999magnet.com/products/112-neodymium-standard-state permanent magnet (PPM) focusing

system was simulated using electromagnetic field analysis

software Maxwell 2D/3D. The BZ exhibited typical cosine curve

along central axis, and the peak value of BZ was high enough to

meet the demand of PPM focusing system at room temperature even

at 200±20 °C. Additionally, a kind of simple cooling structure

for PPM focusing system was designed by setting cooling pipe

between polepieces. Simulated results showed that smooth cosine

curve of BZ was successfully achieved with good control of the

thickness of cooling pipe.

superconducting magnets, cryogenic system

作者:宗占国;刘立强;熊联友;李少鹏;徐庆金;何昆;张亮;高杰;
关键词:BEPCⅡ, superconducting magnets, cryogenic system
单位:Technical Institute of Physics and Chemistry,Chinese Academy

of Sciences;Institute of High Energy Physics,Chinese Academy of

Sciences;
摘要:In the upgrade project of the Beijing Electron Positron

Collider (BEPCⅡ), three superconducting magnetic materials magnets are employed to

realize the goal of two orders of magnitude higher luminosity. A

cryogenic system with a total capacity of 0.5 kW at 4.5 K was

built at the Institute of High Energy Physics (IHEP) to support

the operations of these superconducting devices. For preparing

the commissioning of the system, http://www.999magnet.com the refrigeration process was

simulated and analyzed numerically. The numerical model was based

on the latest engineering progress and focused on the normal

operation mode. The pressure and temperature profiles of the

cryogenic system are achieved with the simulation. The influence

of the helium mass flow rates to cool superconducting magnets on

the thermodynamic parameters of their normal operation is also

studied and discussed in this paper.

Research of Flywheel Energy Storage System on Motor and Generator Controlling Technology

Research of Flywheel Energy Storage System on Motor and Generator Controlling Technology

 Flywheel energy storage (FES) is an advantageous type of late-model energy storage technology, as a pure electromechanical storage system, it has advantage of high specific energy and specific power, non-pollution, long cycle life, has a great development in a short time. At present, FES technology has been successfully applied in many fields, such as uninterruptible power supply (UPS) systems, magnetic materials power systems, hybrid electric vehicles, etc. This paper designed the economical topology of FES system, mainly researched the motor and generator control of permanent magnetic brushless DC motor. This paper proposed a solution of motor and generator controlling system based on the TMS320LF2407A DSP chip, and particularly introduced about the design of hardware and software of controlling system. http://www.999magnet.com The model of the FES system on charge and discharge was built by MATLAB, and the course of charge and discharge was Simulated. 更多还原

混合动力特种车辆用无刷电机全数字控制研究

混合动力特种车辆用无刷电机全数字控制研究

 Hybrid electric vehicle (HEV) has motor and gas engine drive. HEV is practical and exigent vehicle owing to its predominant performance, small exhaust gas and pollution. HEV could also be used for special purpose, such as for cover-up when driving by motor engine, or as field electric vehicle when driving by electrical engine. The HEV fix two drive systems in smaller space. Motor drive system is required to not only possess small volume and light weight, but also achieve performance of electromotor Neodymium Magnets and generator. Especially when the HEV applies the brake, in order to energize the storage battery, it is expected that voltage brought by generator is higher than voltage of the storage battery even if speed of generator is slower. At present, this is a new question for discussion and challenge to the HEV.Brushless direct current motor drive system based on DSP in the HEV is researched by complete digital control manner in the paper. Integrating electromotor and generator, a rare earth permanent magnet brushless direct current motor (REPM BLDCM) control system based on DSP in the HEV is studied. The software control thought achieving performance of http://www.999magnet.com/products/110-sintered-neodymium-magnets electromotor and generator is given on condition that the hardware of control circuit is not changed. It is realized that voltage brought by generator is higher than voltage of the storage battery even though speed of generator is slower. The overall project design, hardware and software design of the control system are presented particularly. The design scheme of the paper is tested and the sample has been manufactured. The satisfactory result is shown by the prototype trials.Finally, shortage in project research is analyzed and suggestion is given. 更多还原