KYN44-12型中置柜联锁装置的改进设计

介绍了12kV中置柜联锁装置的设计原则,分析了现有中置柜联锁装置在实际运行中存在的问题和不足,提出了改进和完善中置柜联锁装置的设计方法。实际应用表明,改进后的中置柜联锁装置的功能更加完善,安全性更加可靠,完全达到了五防闭锁要求。     

Response correction techniques for surrogate‐based design optimization of microwave structures

Simulation‐based optimization has become an important design tool in microwave engineering. However, using electromagnetic (EM) solvers in the design process is a challenging task, primarily due to a high‐computational cost of an accurate EM simulation. In this article, we present a review of EM‐based design optimization techniques exploiting response‐corrected physically based low‐fidelity models. The surrogate models created through such a correction can be used to yield a reasonable approximation of the optimal design of the computationally expensive structure under consideration (high‐fidelity model). Several approaches using this idea are reviewed including output space mapping, manifold mapping, adaptive response correction, and shape‐preserving response prediction. A common feature of these methods is that they are easy to implement and computationally efficient. Application examples are provided. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

The volume integral method of eddy-current modeling: Verification

The volume integral method of eddy-current modeling represents a flaw in metal as a set of electric dipoles located within volume elements or cells defining the flaw volume. Given this dipole distribution, impedance changes may be computed. The electric field of the dipole distribution is determined by an integral equation relating, by means of the electric field Green's tensor, the electric field due to the source to the total electric field in the flaw. The integral equation is solved by assuming that the total electric field is constant in each volume element, resulting in a matrix equation. The method has been programmed for use on a microcomputer. The method and computer program are verified using the analytical solution for a small spherical flaw and three sets of measured impedance data, measured by air-core coils along profiles overlying both surface-breaking and buried simulated flaws of known dimensions. Operating frequencies ranged between 900 and 4000 Hz. Generally agreement is good at lower frequencies ( 1000 Hz). At higher frequencies ( 4000 Hz), the agreement is not as good. This is thought to be due to the inability of the constant electric field approximation to model the steep electric field gradients present in the host metal at high frequency. The results are also sensitive to the method of computation of the electric field due to the source. Some improvements can and should be made to the method.     

Continuous electromagnetic separation of inclusion from aluminum melt using alternating current

A novel scheme about the continuous electromagnetic purification of aluminum melt was put forward based on the utilization of a square separation pipe and a 50 Hz alternating current to produce electromagnetic force. It is experimentally found that with electrical current of 400 A/cm^2, it takes only 10 s to remove 95% inclusion from aluminum melt. Comprehensive numerical simulations were carried out to investigate the dynamics mechanisms behind the process. The results show that the removal of inclusion is attributed to the cooperative effects of electromagnetic buoyancy and the secondary flow induced by the rotational electromagnetic force, and the removal efficient increases with the size of inclusion and the electrical current imposed. Theoretical predictions on the distribution and removal efficiency of inclusion were supported by the experiments.     

精确定位的高带宽新型音圈电机驱动器研究

为了在极高磁道密度（TPI）的硬盘中快速寻道定位、读取数据,研发了一种新型高带宽驱动器组件.该新型高带宽驱动器的音圈电机（VCM）具有独特的音圈结构和磁极（体）排列.在电磁设计中,应用三维有限元分析法（FEA）对一些关键电磁参数及主要结构尺寸进行了优化;预测了系统的动态性能.分析表明,新型音圈电机驱动器产生的电磁力形成了纯力矩,降低了轴承和轴上的反作用力,与传统驱动器相比,更好地抑制了影响伺服带宽的横向准刚性体震动模式（QR模式）,使驱动系统能在高TPI下快速跟踪和精确定位.实验测试了系统的频率响应特性,与理论设计符合得较好.     

变频调速传动系统的电磁兼容分析

在变频调速传动系统中,变频器会产生和受到各种电磁干扰。本文分析了变频调速传动系统的主要电磁干扰源和耦合途径,并阐述了抑制其电磁干扰的措施。     

THEORETICAL INVESTIGATION ON BY-ONLY-CURRENT ELECTROMAGNETIC SEPARATION OF INCLUSION FROM MOLTEN METALS

The electromagnetic field under applied AC and DC current in round and rectangular pipe was systematically investigated, then a concept of "equivalent current density" was proposed for evaluating the inhomogeneous electromagnetic pinch force, and the mono-component removal efficiency and the overall removal efficiency of inclusion were formulated. It is founded that flat pipe is superior to round pipe for the electromagnetic removal of inclusion, and DC current can get a higher removal efficiency than A C current due to absence of skin phenomenon. Under usual condition, a removal efficiency of 52% for 10μm inclusion or more than 92% for 20μm inclusion can be achieved by imposing a current density of 3×106A/m2 in a flat pipe.     

磁性纤维随机混合媒质等效电磁参数的计算

为计及强散射偶极子间的相互作用,引入参量εh和μh,利用广义多重散射理论及MATLAB计算机软件对在2 GHz～18 GHz频率下的体积占空比为8%的铁纤维随机混合媒质等效磁导率的实验值进行曲线的拟合,导出了耦合系数εh和μh,并在此基础上,对体积占空比分别为30%和20%的铁纤维随机混合媒质等效磁导率进行了计算,计算结果与实验吻合良好.     

2000年—2001年磁性功能材料研究和应用新进展

综述了磁性功能材料研究和应用在2000年－2001年间的新进展，其内容包括：（1）自旋电子学；（2）Bi-Fe氧化物的磁性；（3）稀有和稀土金属垂直磁记录材料；（4）新的多层膜磁性材料；（5）磁浮列车。     

水平电磁连铸空心铜管坯组织和性能研究

提出在中试水平的空心铜管坯水平连铸过程中施加工频电磁场,分析其对铜管坯组织和性能的影响.结果表明：与未施加电磁场时相比,施加电流强度为140A的工频电磁场后,水平连铸空心铜管坯的组织显著细化,平均晶粒度由未施加磁场时的3.1提高到8.3,周向组织均匀性也得到明显改善;抗拉强度提高40%左右,延伸率提高50%左右.