含有钢构件的交变电磁场的一种新算法

NEW METHOD OF COMPUTING AC E-M FIELDS CONTAINING STEEL STRUCTURAL PARTS

本文考虑到在计算含有钢构件的工频电磁场时,钢内透入深度仅为1～2mm,提出把钢表面当作场域的边界,钢构件的铁磁特性用非线性边界方程表达.计算时先沿铁磁表面划出一个“内边界”,对其以内的线性场域按通常的数值方法离散并用高斯消去法消去大部分变量,然后对含有非线性边界变量的离散方程用 Broyden 方法求解.实践证明,此法大大减少计算工作量,又能较好地顾及全部铁磁特性,达到较好的精度.

In the computation of industrial-frequency E-M fields involving stecl structural parts, it is customary to make rough simplifications when dealing with the nonlinear parameters of steel,so that it is difficult to obtain accurate rosults.In this paper,considering that the penctration depth in steel is only 1～2mm,a new tactic is given in which the surfaces of stcel parts are taken as boundary of the field,and the ferromagnatic characteristics are repre- sented by a non-linear bounndary equation.In the course of computation,first draw an inner boundary along the ferromagnetic surface;then discretize the lincar domain by ordi- nary numerical method and eliminate the majority of variables by Gauss climination meth- od;and finally solve the discrcte equations involving nonlincar variables by means of Broyden method.Practice verifies that this method can greatly reduce the amont of compu- ation,while the whole ferromagnetic characteristics are adequately considered,lcading to satrsfactory accuracy.