Adaptive finite element meshing at each iterative calculation for electromagnetic field analysis of rotating machines

In this paper, we propose a novel algorithm of the nonlinear time-stepping finite element method for analyses of rotating machines. In the method, the adaptive finite element meshing is applied at each nonlinear and time-stepping iterative calculation with the interpolate calculations of the potentials from the previous step. The primary finite element mesh at each time step is obtained from the final mesh of the previous time step with minor modification due to the movement of the rotor. The proposed method is applied to the characteristics calculations of a permanent magnet motor and an induction motor to verify the method's validity and its usefulness. It is clarified that the proposed method gives almost identical results to the conventional adaptive meshing method whereas the calculation time is reduced to less than 1/10 in most cases. As a result, the proposed method can reduce not only the time of making mesh manually but also the calculation time compared with the usual finite element method without adaptive meshing. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(3): 78–91, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20308