3D harmonic modeling of eddy currents in segmented conducting structures

Abstract

Purpose The purpose of this paper is to describe a semi-analytical modeling technique to predict eddy currents in three-dimensional (3D) conducting structures with finite dimensions. Using the developed method, power losses and parasitic forces that result from eddy current distributions can be computed. Design/methodology/approach In conducting regions, the Fourier-based solutions are developed to include a spatially dependent conductivity in the expressions of electromagnetic quantities. To validate the method, it is applied to an electromagnetic configuration and the results are compared to finite element results. Findings The method shows good agreement with the finite element method for a large range of frequencies. The convergence of the presented model is analyzed. Research limitations/implications Because of the Fourier series basis of the solution, the results depend on the considered number of harmonics. When conducting structures are small with respect to the spatial period, the number of harmonics has to be relatively large. Practical implications Because of the general form of the solutions, the technique can be applied to a wide range of electromagnetic configurations to predict, e.g. eddy current losses in magnets or wireless energy transfer systems. By adaptation of the conductivity function in conducting regions, eddy current distributions in structures containing holes or slit patterns can be obtained. Originality/value With the presented technique, eddy currents in conducting structures of finite dimensions can be modeled. The semi-analytical model is for a relatively low number of harmonics computationally faster than 3D finite element methods. The method has been validated and shown to be computationally accurate.

An Approach for Optimal Pre-Conditioning of the Analytical Field Solution of Slotless PM Machines

“…It is worth mentioning that, in [13], different analytical formulations based on different coordinate systems are investigated without emphasizing the possibility to overcome the mentioned issue. In reference [27], a proper scaling methodology is adopted to solve the problem in Cartesian coordinates.…”

“…This happens in the vicinity, and within the magnet's region, where the magnetization's sudden variation creates discontinuities that cause such a phenomenon. One can overcome this problem, as done in [27], where the σ −approximation 4 is adopted for representing the truncated series. This is done by multiplying the above written expressions ( 43)-( 45) by the following factor (Lanczos σ factor):…”