Tadashi YAMAGUCHI (Mem.), Yoshihiro KAWASE (Mem.) and Shota ISHIMURA We analyzed a three-phase transformer made of laminated non-oriented electrical steel sheets using the 3-D parallel finite element method in order to numerically investigate the influence of the magnetic properties of the electrical steel sheets on the eddy current loss. The difference of the distribution of the magnetic flux and the eddy current between non-oriented and grain-oriented electrical steel sheets are numerically investigated. Moreover, the influence of the magnetic properties of the electrical steel sheets on the eddy current loss around the lap joint parts is clarified.

We developed a 3-D hybrid parallel finite element method with the process-parallelization by MPI and the thread-parallelization by OpenMP. In this method, the domain decomposition method is used in the processparallelization and the multicolor ordering is used in the thread-parallelization. In this paper, we analyze the performance of the hybrid-parallelization through the cogging torque analysis of an IPM motor. As a result, it is possible to calculate the magnetic field faster using MPI and OpenMP at the same time. Hybrid parallelized computation at 8 nodes × 4 threads is 8.7 time faster than non-parallelized computation. Parallelization with OpenMP using the multicolor ordering was able to efficiently parallelize the forward-backward substitutions of ICCG. However, number of ICCG iterations increases due to the multicolor ordering in the hybrid parallelization.

Purpose This paper aims to propose a method to create 3-D finite element meshes automatically using the Delaunay tetrahedralization with the weighted node density technique. Using this method, the adaptive finite element analysis (FEA) was carried out for the calculation of the magnetic field of an eddy current verification model to clarify the usefulness of the method. Moreover, the error evaluation function for the adaptive FEA was also discussed. Design/methodology/approach The method to create the 3-D finite element meshes using the Delaunay tetrahedralization is realized by the weighted node density technique, and Zienkiewicz-Zhu’s error estimator is used as the error evaluation function of the adaptive FEA. Findings The magnetic flux density vectors on the node in the error evaluation function for the adaptive FEA should be calculated with the weighted average by the reciprocal of the volume of elements. Originality/value This paper describes the method to create 3-D finite element meshes and the comparison among calculation methods of the magnetic flux density vectors on the node for the error estimator.

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