Development of Motor Model of Rotor Slot Harmonics for Speed Sensorless Control of Induction Motor

This paper proposes a novel mathematical dynamic model to represent the steady‐state and transient‐state characteristics of rotor slot harmonics of an induction motor for sensorless control. Although it is well known that the rotor slot harmonics originate from the mechanical structure of the induction motor, a mathematical model that describes the relationship between the stator/rotor currents of the induction motor and the slot harmonics has not yet been proposed. Therefore, in this paper, a three‐phase model of the induction motor that depicts the rotor slot harmonics is developed by taking into consideration the magnetomotive force harmonics and the change in the magnetic air gap caused by the rotor slots. The validity of the proposed model is verified by comparing the experimental results and the calculated values. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 63–74, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22478     

Steady-state thermal heat conductivity in rotor of ball asynchronous motor

The problem of how to develop a mathematical model of the heat processes that take place in the rotor of a spherical asynchronous motor under the influence of internal heat sources is considered. An analytic model of the process is suggested that makes it possible to solve the problems of determination of the extreme thermal modes of a motor and is well suitable for the searching procedures of the construction optimization problems.     

单调谐滤波电容器参数选择的工程方法

工程设计中单调谐滤波电容器额定容量与额定电压的选择存在盲目性。为充分利用滤波电容器额定容量增大带来的经济效益、更好地滤除谐波,文章推导出了单调谐滤波电容器额定容量与额定电压和谐波电流的关系式及其实用化变型公式,给出了以基波和各次谐波电压算术和为校验条件的电容器最低额定电压选择式,并结合算例给出了相应的滤波电容器参数。3条滤波支路并联构成的滤波器组的阻抗-频率特性表明了文中公式的正确性和合理性。     

ー种新型宽角搜索喇叭馈源的赋形球形反射面天线

首先提出了一种由喇叭作为馈源的单反射面天线的设计方法,该方法不需求出馈源喇叭的相位中心位置却可确定出馈源最佳位置;通过数值计算发现：馈源相同、反射面口径大小相同的最大增益值时的赋形球形反射面天线比最大增益值时的球形反射面天线有较优良的电性能,可在垂直面进行宽角搜索;最后给出了计算结果及其分析。     

Heat Saturation Time of Solid Spherical Regenerator of HTAC

In order to control the heat saturation time, the temperature field of the regenerators of high temperature air combustion （HTAC） technology after reheating furnace was studied. A one-dimensional unsteady mathematical model was established and discretized through finite difference method. The relationship between the heat saturation time and some factors was determined through the calculation of a program developed by language C. The heat saturation time decreases with the increase of heat convection coefficient, however, the increase of heat capacity, density and radius of regenerator all increase the heat saturation time approximately linearly.     

垂直电偶极子在地-电离层波导中场的球级数解

在非理想导电地面与电离层条件下,我们导出了ELF/SLF垂直电偶极子在球形地-电离层壳体中产生的电磁场的球谐级数表达式,采用一种加速收敛算法,算出了波导中的电磁场分布.根据计算结果,在SLF频段,地面与电离层之间的电磁场可理解为二个"行波"的叠加,且与SLF频段的球面二阶近似算法计算结果吻合很好.在ELF频段,壳体中的电磁场是驻波,其频率变化规律能正确反映出"舒曼"谐振现象.     

球形石英粉的制备方法及性能表征

文章介绍了球形石英粉的制备方法,分析得出了火焰法工艺简单最易实现工业化生产的结论,对球形石英粉的性能参数进行了阐述,通过实验对比了国产球形石英粉和进口石英粉对环氧模塑料性能的影响。     

首台国产化10m~3原级球罐制造技术

在严格执行国家标准及行业标准规定下,大连金鼎石化公司成功地制造了10m3国内体积最小的高强钢原级球罐,实现了国产化,填补了国内空白。本文主要从弹塑性变形和球罐组焊两大方向阐释了球罐制造技术要点及成型控制措施。对今后标准计量型球罐研究工作及提高制造技术水平都有一定的指导作用。     

气力输送技术发展及其在高温气冷堆上的应用

气力输送是一种较为理想的输送方式.本文介绍近年来国内外气力输送技术的发展状况及趋势,概述了气力输送技术所涉及到的气固两相流、数值模拟和试验测量方法,总结了气力输送技术在现代工程上的实际应用情况,重点探讨了高温气冷堆HTR-10吸收球停堆系统、燃料球装卸系统上所使用的气力输送装置的设计分析方法与运行经验.     

施工质量对焊接球节点网架结构可靠性影响的有限元分析

针对焊接球节点网架结构施工中存在的缺陷,提出用刚度退化法仿真施工质量对焊接球节点网架结构可靠性的影响.对网架节点部位采用弹性模量退化法仿真施工过程中存在的质量缺陷,并在考虑施工质量缺陷的基础上,基于蒙特卡罗法运用APDL(ANSYS Parametric Design Language)编制命令流.以结构竖向最大位移作为工程可靠性能的主要指标,对某网架进行可靠性数值分析.计算结果证明施工工艺质量对结构可靠性有较大影响.该方法能帮助工程设计部门在复杂网架的可靠性计算方面考虑施工工艺质量的影响.