The research at the Power Electronic Systems Laboratory (PES) opens up new fields of applications and drives the innovation of power electronics systems in close partnership with both Swiss and international industry. In line with the focus areas of ETH Zurich, fundamentally new concepts, e.g., for sustainable energy systems, sustainable mobility, future datacenters, and medical applications, are of primary interest, along with general scientific challenges and the pursuit of excellence and an internationally leading reputation.
Power Electronic Systems Laboratory (PES) Postings
Nov 07, 2019 | Dominik Neumayr, Dominik Bortis, Johann W. Kolar, Stefan Hoffmann, Eckart Hoene
Inductors realized with high permeable MnZn ferrite require, unlike iron-powder cores with an inherent dis-tributed gap, a discrete air gap in the magnetic circuit to prevent saturation of the core material and/or tune the inductance value. This large discrete gap can be divided into several partial gaps in order to reduce the air gap stray field and consequently the proximity losses in the winding. The multi-gap core, realized by stacking several thin ferrite plates and inserting a non-magnetic spacer material between the plates, however, exhibits a substan-tial increase in core losses which cannot be explained from the intrinsic properties of the ferrite. In this paper, a comprehensive overview of the scientific literature regarding machining induced core losses in ferrite, dating back to the early 1970s, is provided which suggests that the observed excess core losses could be attributed to a deterioration of ferrite properties in the surface layer of the plates caused by mechanical stress exerted during machining....