处理电磁场有限元运动问题的新方法

该文总结了电磁场有限元分析中处理运动问题的现有处理方法，指出现有方法中存在的效率低、通用性不强和时间步长不确定等缺点。通过对现有独立坐标系方法的改进，提出一种新的处理方法。新方法不再受运动边界节点必须始终一一对齐的约束，在计算过程中时间步长可以保持为定常数，而空间步长由计算结果决定，取消了有限元网格单元边长对空间步长的限制。通过对异步电机暂态起动过程的计算，证明了新方法的有效性。新方法可以有效地提高电磁场有限元分析中对运动问题处理的时间效率。

A NEW METHOD TO DEAL WITH THE MOTION PROBLEM IN ELECTROMAGNETIC FIELD FINITE ELEMENT ANALYSIS

In this paper, methods that have been used to deal with motion problem in electromagnetic filed Finite Element Analysis (FEA) are summarized. The shortcomings existed in those methods are pointed out, such as inefficiency, lack of universal property and time step indetermination. In order to overcome these shortcomings,A new method is presented, which is yielded by improving the independence coordinate method. In new method, the nodes in moving boundary are not required to alignment and the choice of time step is flexible. During the calculation of a specific problem, the step of time is constant, and the step of space is determined by the calculation result. So the limitation on the space step, which is produced by the finite element mesh size, is eliminated. The validity of the new method has been proved in calculation for the transient process of the induction machine. With the new method based, the time efficiency would be increased when the moving problem of the electromagnetic field is solved with the finite element method.