Increase of tape wound core losses due to interlamination short circuits and orthogonal flux components

Abstract

High performance laminated core materials are nowadays used in several different applications, from some Watts to some Megawatts and from some tens of Hertz to some hundreds of Kilohertz. Cutting laminated or tape wound cores in order to obtain a desired geometry results in higher core losses mainly due to the introduction of short circuits between layers of magnetic material and also due to the flux which is perpendicular to the layer plane as given for the fringing field of inductors or the stray field of transformers. This paper verifies the influence of some machining methods on the increase of core losses and shows an approach to keep the effect minimized. Furthermore, the importance of considering core losses due to perpendicular flux is verified for a cut core inductor and a transformer arrangement.