超高速发电机铁心损耗计算及影响因素研究

针对微型涡喷发动机用的超高速发电机损耗的计算方法进行研究。首先,基于滑移边界建立了高速电机空载磁场有限元模型计算,得到定子铁心磁密随时间变化波形,通过傅里叶分解得到基波磁密和各次谐波磁密,根据Bertotti铁耗计算模型进行定子铁耗分布的计算,研究了铁心材料、定子结构尺寸及不同转速情况下的铁耗大小。

探究超高速电机铁芯片模具的设计与制造

电机铁芯片作为电机定子部分,在实际制造过程中需要借助超高速模具提升电机铁芯片生产质量。在此之上,本文简要分析了超高速模具的设计特点,并通过应用超高速加工技术、引进超高速扫描系统、调整超高速模具冲压、优选超高速模具材料等方法,以此确保电机铁芯片在超高速模具下实现高效生产。

现场进行发电机铁损试验的方法探究

对发电机铁损试验进行分析,测算发电厂励磁变参数,提出利用励磁变进行发电机铁损试验的方案。

一种空调铁壳风扇电机定子嵌线方法及其绝缘部件

为了解决空调铁壳风扇电机定子生产效率低下,及相间绝缘手工安装不到位导致绕组不能完全隔开的安全隐患问题,采用筒状绝缘构件作为电机相间绝缘部件,并改进定子的嵌线方法,在绕组嵌线过程中自动装入定子。筒状绝缘构件结构简单,易于加工制造。改进的定子嵌线方法可以提高定子的生产效率,并消除手工操作的绝缘安全隐患。利用改进方法制作的电机定子经大批量试用,效果良好。

盘式电机背铁零件加工工艺设计

针对盘式电机背铁在转子旋转时易脱落、电机性能易受背铁涡流影响等问题,设计了盘式电机背铁零件加工工艺。通过对盘式电机背铁零件的图纸分析,得出背铁的结构、尺寸、角度要求和加工余量,选择适合的毛坯材料和尺寸,确定零件加工工艺流程和工序尺寸,选择适合的加工设备和刀具,进行零件加工。该文研究设计的背铁零件加工工艺可有效解决现有技术问题,能满足加工精度要求以及市场对背铁结构和功能的要求,能够提高效率,减少材料浪费。

软磁复合材料在电机中的应用

软磁复合材料是运用粉末冶金技术制造的一种新型材料,具有各向同性、低涡流损耗和可加工成任意形状等优点,非常适合作为电机铁心材料,特别是在中高频工作条件下。文章介绍软磁复合材料的性能特点,再分类归纳这种材料在电机中的应用研究情况,最后讨论目前存在的不足及发展方向。

基于12/8磁阻电机极性分布对电机损耗及温度场的影响

开关磁阻电机(switched reluctance motor,SRM)结构简单、坚固和转子上无永磁体与绕组,具有体积小、功率低和轴向利用率高的优点,可用于电动汽车驱动领域。而紧凑的结构绕组散热面积小和热负荷高,使得准确计算电机的损耗与温升变得十分重要。以12/8 SRM电机为例,推导电机各部分铁损模型,分析不同接线方式下电机磁极分布对电机铁损以及温升的影响。通过有限元计算电机的铁损验证模型计算结果,利用磁-热单向耦合方法对SRM进行温度场分析,分析电机各主要部件的分布规律,为SRM的温度预估以及散热提供依据。

电工软磁材料旋转磁滞损耗测量及建模

电力变压器和电机中存在旋转铁心损耗是其损耗预测不准的主要原因之一。针对该问题,提出电工软磁材料旋转磁滞损耗测量及建模方法。首先,矢量磁滞损耗分解为切向损耗和法向损耗两部分,分别根据圆形旋转损耗和交变损耗建模。其次,对软磁复合材料和无取向电工钢片进行模型参数辨识,并比较两种材料的损耗特性和模型参数。最后,利用三维磁特性测量装置进行多种励磁模式下的损耗测量,并对比实验结果与模型预测值。结果表明,在旋转复杂激励下,所提出的模型比传统的Steinmetz模型有更高的精度。

磁性槽楔

采用磁性槽楔的主要作用是降低电机的空载附加损耗和高频杂散损耗(主要是铁心脉振损耗和表面损耗),因此采用了磁性槽楔以后,凡与这些损耗有关的参数均可得到改善。通过在生产实际中推广应用,效果很好,达到了降低高压电机铁耗的目的。

Geochemistry of Iron,Sulfur and Related Heavy Metals in Metal-Polluted Taihu Lake Sediments

To understand the geochemical characteristics of iron and sulfur and the extent of iron-sulfide minerals influencing heavy metal behaviour in metal-polluted sediments of Talhu Lake, two sites, in Meiliang Bay （ML） and Wuli Lake （WL）, were selected to study the fractionation of iron, sulfur and related heavy metals. There were relatively high concentrations of Fe^2＋ and low concentrations of total S^2- in porewaters, indicating that conditions in these sediments favored iron reduction. The concentrations of acid volatile sulfides in sediments were 1.9-9.6 μmol g^-1 at ML and 1.0-11.7 μmool g^-1 at WL, both in the range of values detected in unpolluted lakes. Pyrite-S was 10.2-49.4 μmol g^-1 at ML and 10.3- 33.0 μmol g^-1 at WL, accounting for more than 69% of the reduced inorganic sulfur at both sites. The low degree of sulphidization （〈 14%） and pyritization （〈 10%） indicate that sulfate may be the limiting factor for pyrite formation. The extractability of Mn, Cu, Pb, Zn, Ni, and Cr in sediments all suggest that sulfides are not the major binding phase for these metals during early diagenesis. Sulfur may play a modest role in the geochemistry of iron and traced metals in the sediments.

Study on three dimensional electromagnetic model for permanent magnet linear synchronous motor

In this paper, with the non-salient pole permanent magnet linear synchronous motor (PMLSM)being cited, by using Fourier transform method and "slot-by-slot", "pole -by-pole" current approach, a 3D electromagnetic field model of PMLSM is established. Special attention is paid to its structure and the influence of longitudinal and transverse end effect. The distribution of electromagnetic field of PMLSM can be obtained directly and promptly by using FFT algorithm. It can also be used for the analysis of other LSM.

Development of Ferroelectric RAM （FRAM） for Mass Production

we have developed ferroelectric capacitor fabrication technique to realize low-voltage and high-density ferroelectric random access memory （FRAM）. High temperature deposited IrOxtop electrode reveals high crystalline quality which drastically reduces the degradation of ferroelectric film by preventing hydrogen diffusion into ferroelectric film. This improvement enables us to commercialize highly-reliable 1T 1C FRAM with memory density of 4 Mb or larger.

An Extended Extrinsic Mechanism for Anomalous Hall Effect

The extrinsic mechanism for anomalous Hall effect in ferromagnets is extended to include the contributions both from spin-orbit-dependent impurity scattering and from the spin-orbit coupling induced by external electric fields. The results obtained suggest that, within the framework of the extrinsic mechanisms, the anomalous Hall current in a ferromagnet may also contain a substantial amount of dissipationless contribution independent of impurity scattering. After the contribution from the spin-orbit coupling induced by external electric fields is included, the total anomalous Hall conductivity is about two times larger than that due to soin-orbit dependent impurity scatterings.

ab initio Study of Electronic Structure and Magnetic Properties of a Novel Two-Dimensional Copper(II)-Radical Complex [Cu(NTTmPy)2(N3)2]n

The full-potential linearized augmented plane wave (FPLAPW) method with the generalized gradient approximations (GGA) is applied to study the compound [Cu(NTTmPy)2(N3)2]n (NITmPy = 2 - (3' - Pyridy1) -4, 4, 5, 5 - tetramethylimidazolin - 1 - oxy1 - 3 - oxide). The total density of states (DOS) and the partial density of states (pDOS) are calculated to explain the electronic and the magnetic properties of [Cu(NTTmPy)2(N3)2]n. It is found that [Cu(NTTmPy)2(N3)2]n is stable in the ferromagnetic state and the magnetic moment of the molecule mainly comes from the Cu atoms (0.518 μB) with partial contribution from N, O atoms of nitronyl nitroxide radicals. There exist orbital hybridization between 3d orbital of Cu and p orbitals of N(1) (from pyridyl rings of the NITmPy ligands) and N(4) (from azido group) and the weak direct exchange interactions between Cu and O atoms of nitronyl nitroxides. In addition, the bridging carbon atom (C(6)) carries a significant negative spin density (-0.019 μB). The sign alternation of the magnetic moment along zthe pyridyl ring is obtained, which agrees with experiments.

Dynamic Analysis of Micro-machined Diamagnetic Stable Permanent Magnet Levitation System

A novel micro-machined diamagnetic stable.levitation system （MDSLS） which is composed of a free permanent magnetic rotor, a ring lifting permanent magnet and two diamagnetic stabilizers was presented. The static and dynamic stable characters of MDSLS were analyzed. The coupled non-linear differential equations were used to describe six-degree-of-freedom motion of the levitated rotor, and the equivalent surface current and combined dia- magnetic image current method were utilized to model the interaction forces and torques between the lifting perma- nent magnet and rotor permanent magnet and also between the rotor permanent magnet and diamagnetic sub- strates. Because of difficulty to get analytical solution, the numerical calculation based on Runge-Kutta method was used to solve the dynamic model. The vibration frequencies were identified b~ fast Fourier transform （FFT） analysis. According to their resonance characteristics and parameters, the translational and angular dynamic stiff- ness were also calculated. The results show that the levitation of the rotor in MDSLS is stable, and the MDSLS is potential for the application in levitation inertial sensor.

Mechanism of current efficiency improvement of Zn-Fe alloy electroplating by hydrogen inhibitor

The effect of hydrogen inhibitor on partial current densities ofZn, Fe and differential capacitance of electrode/electrolyte interface, and adsorbing type of hydrogen inhibitor were studied by the methods of electrochemistry. The mechanism of current efficiency improvement were explained from the point of valence electron theory. The results indicate that the partial current density of Fe increases in addition of hydrogen inhibitor, which reaches the maximum of 0.14 A/dm^2 when current density is 0.2 A/din〈 Differential capacitance of electrode/electrolyte interface decreases obviously from 20.3μF/cm^2 to 7 μF/cm^2 rapidly with the concentration varying from 0 to 20 mL/L, because hydrogen inhibitor chemically adsorbs on active points of Fe electrode surface selectively. Element S in hydrogen inhibitor with negative electricity and strong capacity of offering electron shares isolated electrons with Fe. The adsorption of H atom is inhibited when adsorbing on active points of Fe electrode surface firstly, and then current efficiency of Zn-Fe alloy electroplating is improved accordingly.

Properties of Brushless DC Machine Induced by Permanent Magnets Applied to a Traction Drive

The paper presents a mathematical model ofbrushless DC machine induced by permanent magnets. Its construction uses the classical model of permanent magnet synchronous machine and induced model of power inverter using the serraphil form. The results of the computer simulation were presented for such states： startup, work under active constant load and the behavior of the machine in terms of exponential and stepping change of the power inverter＇s control angle.

Influence of DSP controller on performance of a permanent magnet brushless AC drive in flux-weakening mode

The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was operated at high-speed in the flux-weakening mode with the fixed-point DSP. The investigation showed that this was due to the on-line compensation of the winding resistance voltage drop and quantisation errors associated with the fixed-point architecture of the DSP. A simple look-up table scheme is proposed to eliminate the oscillation and to achieve extended flux-weakening capability.

Losses Calculation of an Aerospace Retraction Wheel Motor with Regarding to Electromagnetic-Field Analysis Investigation

A 3-D FEA （finite element analysis） transient and steady-state design proposal for high-speed with Nd-Fe-Br （reversible） magnets in aerospace application will be examined under design considerations of n = 12,000 rpm, short-duty, sinusoidal drive, low cogging, high efficiency at peak torque, and etc. for an ARWM （aerospace retraction wheel motor）. In construction, the PMs （permanent magnets） fixed on the rotor core which is surface-mOunted magnets retained by a carbon-fiber bandage. Redundant windings, resistant to fault propagation have accounted. Besides, an axial water-jacket housing without end-cap cooling has involved. All performed characteristic performances of the correlated ARWM will verify by comparison through 2-D and 3-D FEA results. In this paper, design process has dealing with determination of various kinds of losses such as electromagnetic and mechanical losses. In terms of both classified losses, copper, stator back iron, stator tooth, PM, rotor back iron, air-friction and sleeve losses were calculated. The 3-D end-winding effects were included in the modeled ARWM by the authors.