Convolution permeance operator for eddy-current affected steel sheets in 2D transient electromagnetic field computations

Abstract

A local inhomogenity effect in electromagnetic devices is dealt with. The flux density distribution in laminated cores of electrical machines is affected by eddy-current reactive fields inside the sheets, which will reduce the effective permeance of magnetic circuits for high-frequency flux components. The immediate inclusion of this effect in numerical field computations would usually cause an enormous effort concerning the spatial discretisation or could even become impossible, e.g., in 2D. An alternative approximative method for considering this locally strong variation of field quantities caused by skin-effect and eddy-currents is discussed with the focus on transient computations. The method outlined here is based on convolution integrals well known from signal processing. It locally enriches the formulation of field equations by a special material operator.