用边界元法计算含有电位悬浮导体的静电场问题

本文提出用边界元法计算含有电位悬浮导体静电场边值问题,推导出用边界元法计算这类边值问题的边界元方程,给出计算这类边值问题增列约束方程的方法,理论分析和实例结果表明,用边界元法计算含有电位悬浮导体的静电场问题,是一种非常有效的计算方法,可以方便地应用于静电场工程问题的设计与计算。     

无限大电极系统的保角变换边界元分析

本文提出用保角变换边界元法计算含有无限大电极系统的二维静电场边值问题，保角变换将无限大电极系统的无穷边界无界场域边值问题变换为有界场域边值问题，再利用具有诸多优点的边界元法进行求角，充分发挥保角变换和边界元法的各自优势，拓宽二者的求解范围。     

静电场第四类非混合边值问题的弱问题

本文在Galerkin意义下讨论了静电场第四类非混合边值问题的有限元法，证明了静电场第四类非混合边值问题的弱问题的等价性，广义解在相差一个常数意义下唯一及广义解唯一的条件，并将弱问题的积分方程离散化，对刚度矩阵的形成进行了分析，算例验证了本文所述定理和方法。     

用边界元法计算特殊静电场问题

本文提出了用边界元法计算一类要求系统所带量代数和为零，电位参点难以选定的静电场问题，推导出计算这类静电场问题的边界元方程，提出求解这类问题增列约束方 程的方法。     

B样条曲面边界元方法及其在特高压绝缘子串电场计算中的应用

在计算特高压绝缘子串三维静电场的边界元法中,为了精确确定电场强度和电位分布,提出用双2次B样条曲面拟合实际边界面的B样条曲面边界元法。该方法利用二阶剖分单元的节点坐标信息来求解双2次B样条曲面参数方程,再利用B样条曲面参数方程和面积比值法定义对应于B样条曲面单元4个顶点节点的形状函数;用B样条曲面单元4个顶点作为计算节点,与二阶四边形边界元法相比,计算量大大减少;与线性平面边界元法相比,双2次B样条曲面与实际边界面更接近,从而可以明显提高计算精度。用球形电极和球板电极的电场分布计算进行验算,结果表明:在网格剖分节点数相同时,B样条曲面边界元法的计算精度明显优于线性边界元法。最后,将B样条曲面边界元法应用于交流特高压绝缘子串的电场强度和电位分布计算。     

新型曲面三角形边界元法及其在电场计算中的应用

用边界元法计算工程三维静电场时,为了减少计算节点数同时提高计算精度,提出了新型曲面三角形边界元方法.该方法利用二阶单元剖分边界面,再利用面积比值法构造对应于二阶单元的3个顶点节点的形状函数;以二阶单元的3个顶点节点为计算节点,与二阶三角形边界元法相比,大大减少了计算量;与一阶平面三角形边界元法相比,提高了计算精度.取球形电极的电场分布计算为例进行验算,计算结果表明:与一阶剖分的平面边界元法相比,网格剖分节点相同时,新型曲面三角形边界元法的计算精度明显提高;在计算精度要求相同时,新型曲面三角形边界元法计算节点数较少.     

二维静电场边界元法的积分精度问题

基于笔者开发的二维边界元计算软件 ,研究了二维开域静电场边界元法中高斯积分的精度问题 ,分析了影响该积分精度的相关因素———距离、角度、单元尺寸和高斯积分点个数等 ,通过程序计算和数据分析 ,得出了上述因素对积分精度的影响 ,提出了达到高积分精度的积分判据 ,为以后的二维开域静电场边界元法计算提出了参考依据     

用混合有限元和边界元法求解圆筒型直线异步电机的稳态特性

用混合有限元和直接边界元法计算了圆筒型直线异步电机的稳态运行特性,电机的初级和次级场域用有限元法分析,空气隙场域用边界元法分析,同时考虑了铁心的饱和,涡流效应以及齿槽效应的影响。     

用混合有限元和边界元法求解圆筒型直线异步电机的稳态特性

用混合有限元和直接边界元法计算了圆筒型直线异步电机的稳态运行特性。电机的初级和次级场域用有限元法分析，空气隙场域用边界元法分析，同时考虑了铁心的饱和、涡流效应以及齿槽效应的影响。计算结果与实验结果吻合较好。     

基于球坐标的三维静电场曲边三角形边界元法

为了精确计算三维静电场中球形电极表面的电场强度,提出了基于球坐标变换的球面曲边三角形边界元法。该方法中积分的区域为球面,求解函数采用球面上球坐标线性插值,单元的外法线方向为严格的球面法线方向。计算结果表明,与平面直边单元相比,在网格剖分节点相同时,球面曲边三角形边界元法的计算精度明显提高。在计算精度要求相同时,球面曲边三角形边界元法节点数较少,具有计算速度快,占用计算机内存少等优点。     

计算电位悬浮导体电场问题的有限元外推法

提出了应用有限元外推法计算含有电位悬浮导体的电场问题,给出了基于虚拟介电常数法的有限元外推计算格式,经理论分析和实例计算结果证明,可以比较方便地应用于含有电位悬浮导体的静电场工程问题的设计和计算之中。     

二维磁场分析的多极理论及应用

本文从二维静态电场分析多极理论出发，推导出二维磁场分析的多极理论通解及其使用规则，通过对两个磁场问题的计算分析，表明二维磁场分析的多极理论是可行的，具有较高的精度，可以很方便地应用于具有圆弧边界和直线边界的二维磁场的分析与设计。     

Optimization of support insulators used in HV systems using support vector machine

In this paper support vector machine (SVM) has been used for optimization of electric field along the support insulators used in high voltage (HV) systems. To illustrate the effectiveness of SVM in optimizing electric field problems, two axi-symmetric cases have been considered one having an insulator with a contour that is quarter ellipse and the second one having a porcelain core solid insulator. The training and the test data for the SVM have been prepared by electrostatic field computation using indirect boundary element method (BEM). It is observed that once the SVM is trained it is able to give results with mean absolute error of less than 1.5% when compared with the analytically obtained results. The SVM designed for insulator contour optimization is first trained with the results obtained from electric field computation for some predetermined contours of the arrangements under consideration. Then the trained SVM is used to produce an optimized insulator contour in such a way that the desired stress distribution can be obtained on the insulator surface. The results obtained from the present study show that the trained SVM is adequately efficient to optimize insulator contours in order to have the desired stress distribution along the insulator surface     

轴对称恒定电磁场的标量边界元法

本文从三维恒定电磁场的边界积分方程及基本解出发推导出轴对称恒定电磁场的标量边界元法。这包括边界积分公式，基本解及边界元方程的导出，系数矩阵元素的计算与场量的求取。文中特别对系数元素计算时奇异积分的处理进行了详细的探讨。通过对两个电场问题的计算分析，表明建立的方法是可行的，具有较高的精度，可以很方便地应用于具有轴对称特性的电工设备的恒定电磁场分析与设计。     

计算发电机端部磁场的差分方法

本文用积分方法对圆柱坐标下的微分方程进行离散化。将一个三维的恒定磁场问题化为三个平面问题,使求解简单化。并给出了差分格式。     

Concurrent boundary element computation

A major limitation of the boundary element method (BEM) for the solution of electrical potential problems is the long computational time required. However, a large portion of the calculations involved can be viewed as being parallel in nature and can therefore be computed concurrently. This paper makes an effort to increase the efficiency of the BEM process using transputer-based multiprocessor computing techniques. The algorithms developed may equally well be applied to any multiprocessor system. The application selected to demonstrate the technique is the solution of an electrostatic problem governed by a two-dimensional Laplace equation. A parallel algorithm for problem setup and field extraction using BEM is designed and implemented on a transputer array. Special attention is directed to the utilization of the parallel processors to achieve maximum efficiency. The analysis in this work concentrates on the communication strategies for passing data between processors as well as a consideration of the workload attributed to each processor. The parallel algorithms were implemented using 3L Parallel Fortran; however, the choice of topology for the overall BEM implementation was limited by the fact that certain parts of the algorithm could only utilize a pipeline configuration of processors. Comprehensive results for the parallel BEM algorithm are given and they are encouraging, indicating that parallel processing has much to offer when applied to the boundary element method.     

电磁场边值问题的并矢格林函数法

根据文献［１］所提出的“矢量－并矢”法中的不同组合，应用并矢格林函数理论和格林公式，利用电流源Ｊ（Ｒ）的分布及边界面上的场量边值条件，导出了Ｐ＝Ｈ（Ｒ）和Ｑ＝ｅ（Ｒ｜Ｒ’）及Ｐ＝Ｈ（Ｒ）和Ｑ＝ｍ＝（Ｒ｜Ｒ’）这两种情况下电磁场边值问题的解。此方法求解简单，物理概念清晰。     

A simple introduction to finite element analysis of electromagneticproblems

An elementary tutorial introduction in finite-element numerical analysis is presented. The finite-element method is applied to Laplacian electrostatic field problems. Suggestions are offered on how the basic concepts developed can be extended to finite-element analysis of problems involving Poisson's or the wave equation. A step-by-step procedure for coding the numerical method is presented; a useful, working FORTRAN program is also included