A one‐converter contactless charger for electric vehicles

A simple and reliable contactless battery charger for electric vehicles is proposed. Its feature is a unitized power factor correcting (PFC) converter and a high‐frequency inverter (HFI) where the low‐side switch of the HFI also works as the boost switch of the PFC in discontinuous conduction mode, which results in a high input power factor and low harmonic distortion without any feedforward control. The exiting current of the inductive connector, compliant with SAEJ1773, works effectively to make the converter operate in zero voltage switching (ZVS) condition. Another feature is that the charger is controlled by a single magnetically coupled variable frequency oscillator developed by the authors. This paper analyzes the circuits, gives a design example, describes the inductive connector and the oscillator, and presents experimental results. A 1.7‐kW output prototype charger achieved a charging efficiency of 87.4% for total one cycle charging, an overall efficiency of 90% at heavy load, and an input power factor of over 98%. © 2000 Scripta Technica, Electr Eng Jpn, 132(2): 73–81, 2000     

磁控大电流MAG焊的磁头优化及应用研究

从增强工程实用性、磁控效果、冷却效果和气体保护效果等角度出发,设计了两种新型的磁场发生装置,并进行了磁控大电流MAG平板堆焊和角焊缝焊接工艺试验.试验结果表明,采用所设计的磁场发生装置进行焊接时,焊接飞溅很小,焊缝成形良好,明显优于采用空心线圈作为磁控器件的焊接效果.     

液固磁稳定床中固含率分布与液相返混特性

固含率分布和液相返混系数是液固磁稳定反应器放大与优化所必需的基础数据。采用床层膨胀高度法、光电法及瞬态点源示踪技术,研究了以SRNA-4催化剂为固相的液固磁稳定床中固含率分布和液相返混特性。试验结果表明,固含率轴向分布基本均匀,径向为“扁-陡曲线”分布。固含率随磁场强度和颗粒尺寸的增大而增大,随液体粘度和空塔液速的增大而减小。轴向液相返混系数随磁场强度和液体粘度的增大而减小,随空塔液速和颗粒尺寸的增大而增大。回归得到了固含率和轴向普朗特准数的关联式,预测值与试验值吻合良好。     

磁悬浮飞轮抱式锁紧机构碳纤维弹片优化设计

针对磁悬浮飞轮抱式锁紧机构用一体式碳纤维弹片,提出了一种新型优化方法。通过将碳纤维弹片等效为悬臂梁模型,对其进行静力学和动力学分析,得到其最大过盈摩擦力、锁紧力、解锁力、最大弯曲应力和一阶共振频率。基于有限元法,对弹片进行灵敏度分析,得到弹片上端和下端两组互不相关的结构参数,并分别对两组结构参数进行优化设计。优化结果表明,当弹片个数为12时,质量达到最小60.5 g,比最初170 g减少了64%。根据优化结果研制了一套锁紧机构,利用三轴正弦扫频振动和随机振动试验,检验锁紧机构对磁悬浮飞轮系统的保护效果。结果显示,振动试验中定、转子间最大相对振动位移为50μm,远小于磁悬浮飞轮保护间隙200μm,表明锁紧机构能够对飞轮系统实施有效保护。     

气固磁场流态化分选细粒煤

利用研制的横流式气固磁稳定流化床,以0.074~0.045 mm粒级磁铁矿粉和磁珠作为高密度和低密度分选介质,对6.0~0.5 mm 细粒煤进行连续分选试验。结果表明：当处于稳定流化时,磁场气固流化床比普通气固流化床具有更宽的稳定操作气速范围;外加磁场使磁性颗粒沿磁力线形成平行磁链,增大了床层空隙率,形成了分布均匀的通道,气体通过时不会产生气泡,由此形成了稳定的散式气固磁场流化床;高密度分选和低密度分选的可能偏差分别为0.085,0.075 g/cm 3 。     

About Faraday rotation in bulk media,in a magneto-active layer and in a magneto-photonic crystal layer

ABSTRACT

In this paper, we studied the influence of medium parameters and the wavelength of incident light on Faraday’s rotation and on the ellipticity of polarization. The results of comparison of these dependencies for bulk (unbounded) media, for a layer of a magnetically active medium of finite thickness and, finally, for a magneto-photonic crystal layer are investigated. The dependences of the reflection on the same parameters are investigated too.     

主被动磁悬浮高速转子系统的自动平衡控制

针对主被动磁悬浮转子高速旋转时质量不平衡和被动磁轴承磁中心的偏移导致的同频振动力问题,提出了一种基于位移陷波加前馈补偿的自动平衡控制方法。首先,在转子为零位移控制状态下提取控制电流的同频成分,计算获得与被动磁轴承磁中心偏移相关的参变量;然后,在额定转速下设计通用陷波器以消除同频电流,前馈补偿主动磁轴承、被动磁轴承位移负刚度力和被动磁轴承磁中心偏移力,使主被动磁轴承的同频输出力为零,实现了转子绕惯性中心旋转。对提出的方法进行了仿真和实验验证并与仅补偿质量不平衡的算法进行了对比。仿真结果显示:提出的方法的同频磁轴承力减小到了只进行质量不平衡补偿算法的6%;实验结果显示:同频振动加速度减小到只进行质量不平衡补偿算法的23.3%。仿真和实验验证了该方法的有效性,表明该方法对同频振动抑制效果显著,实现了转子的自动平衡控制。     

磁悬浮高速离心式鼓风机的喘振检测

针对磁悬浮高速离心式鼓风机的喘振问题,提出了一种基于磁悬浮轴承的喘振检测方法。该方法采用通用同频陷波器滤除转子位移中的同频分量,消除了同频扰动对喘振检测的影响;通过分析不同收敛因子对喘振频率估计的作用,基于自适应估计提出了变收敛因子的喘振频率和幅值估计方法,减小了低频信号的干扰,提高了喘振信号检测的快速响应能力。最后,分析了改进检测算法的收敛性,并在100kW磁悬浮离心式鼓风机测试系统上进行了实验验证。实验结果表明,改进后的喘振检测算法可在喘振发生前检测出喘振先兆旋转失速信号,在喘振发生0.23s内检测出喘振信号,较改进前的检测结果提高了2.6s。该检测方法无需外加其它检测单元,算法简单、快速,计算量小、并可有效地反映喘振发生过程中频率与振幅的变化。     

Study on preparation of protein‐imprinted soft‐wet gel composite microspheres with magnetic susceptibility and their characteristics. I. Preparation and particle morphology

Protein‐imprinted soft‐gel composite microspheres with magnetic susceptibility (MS‐PIGMs) were prepared by inverse suspension polymerization, using Fe₃O₄ particles as magnetically susceptible component, acrylamide (AM) and N,N′‐methylenebisacrylamide (BisAM) as polymeric matrix components, toluene as solvent, and bovine serum albumin (BSA) and lysozyme (Lyz) as templates, respectively. The surface morphology of MS‐PIGMs was observed by environmental scanning electron microscope (ESEM) and scanning electron microscope (SEM). The effects of the kinds and amount of dispersants, stirring rate, the amount and adding methods of initiator, the amount of Fe₃O₄ and monomer concentration on particle morphology of MS‐PIGMs, as well as the effects of crosslinking degree on swelling ratio and particle morphology in wet condition were investigated in detail. ESEM and SEM photographs showed that the resulting MS‐PIGMs were all spheroid form and had large quantity of regularly distributed pores in wet condition, which close in dry condition, and the experimental results indicated that all the affecting factors had obvious effects on particle morphology of MS‐PIGMs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 684–694, 2006     

搅拌器和搅拌容器的发展

从资源的最合理利用和环境保护的观点论述当今在搅拌器和搅拌容器方面的最新发展。主要论述五个问题：搅拌器机械密封的进展;磁力驱动搅拌器的发展;高黏度物料搅拌器和新型搅拌桨叶的发展;新型转子／定子式搅拌器的发展和多功能搅拌器和搅拌过程的自动化。