Development of Methods for Analyzing Eddy Currents in Moving Conductors and Verification

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The methods for analyzing 3-D eddy currents in moving conductors are developed and the various methods are compared with each other. The acceleration of the ICCG method which is used as solver for large linear equation systems is also investigated. The results obtained can be summarized as follows :1.Development of Methods for Analyzing Eddy Currents in Moving ConductorsThe methods for analyzing magnetic circuits with moving conductors are systematically classified and the preferable method for each circuit is shown. The treatment of eddy current term using moving and fixed coordinate systems are investigated and the software is developed.2.Comparison of Various MethodsThe methods using moving and fixed coordinate systems are compared with each other from the standpoints of accuracy, memory requirement and CPU time by using a verification model. The results obtained can be described as follows :(1) In the transient analysis, the moving coordinate system is superior from the standpoints of accuracy, computer storage and CPU time.(2) In the dc and ac steady state analysis for large Peclet numbers, spurious oscillations occur when using a fixed coordinate system with ordinary Galerkin finite element method. The solution using a moving coordinate system, however, can be obtained with a high reliability. The optimal value of the time step for the moving coordinate system is also clarified.3.Acceleration of Solving Large Linear Equation SystemsThe algorithm for the calculation of the distribution of non-zero entries in ICCG method is improved in order to accelerate the computation. It is shown that the convergence characteristics of the ICCG method for the analysis using magnetic vector potential and edge elements can be considerably massively improved by introducing the electric scalar potential.