The Effects of Sheet Thickness and Excitation Frequency on Hysteresis Loops of Non-Oriented Electrical Steel

Abstract

The paper focuses on modeling the rate dependence of hysteresis loops in conductive magnetic materials. The concept, which was advanced about fifty years ago by Chua, is discussed. It is shown that the viscous-type equation considered by Zirka and co-workers belongs to the class of Chua-type models. The dynamic effects are described with a simple fractional power law. The value of the exponent in the above-mentioned power law may be assessed on the basis of measurements of coercive field strength at different excitation frequencies. To verify the usefulness of the approach, the measurements of hysteresis loops were carried out at several excitation frequencies under standardized conditions for two grades of non-oriented electrical steel. The modeled curves are in a good correspondence with the measured ones. The considered model uses fewer parameters than approaches based on three-term loss separation schemes.

Modeling Dynamic Hysteresis Curves in Amorphous Magnetic Ribbons

“…The present paper is a follow up of previous research devoted to modeling hysteresis curves under an increased excitation frequency [1]. The aim of the paper is to demonstrate the usefulness of a viscous-type equation, considered previously by Zirka et al [2], as a means to describe the so-called excess field component.…”

“…The issue of loss separation in soft magnetic materials may be tackled from different perspectives, and a recent review on the subject can be found in [1]. Here, we follow the so-called two-term separation scheme, in which field strength at an increased excitation frequency is computed from…”

“…in which H stat (B) corresponds to the material response under slow driving (quasi-static excitation); the exponent 1/ν is fractional, and it accounts for viscous effects mostly due to eddy currents in different time and spatial scales in the conductive material, whereas r(B) = K 1 − (B/J sat ) 2 , where J sat is the saturation polarization and the proportionality coefficient K is found to vary both on induction and its rate, K = K(B, dB/dt) [1].…”

“…As indicated in the previous study [1], the starting point for the analysis is the dependence of coercive field strength vs. frequency. Figure 4 depicts the experimental dependence H c = H c ( f ) for the examined Metglas core.…”

“…As indicated in the previous study [1], the starting point for the analysis is the dependence of coercive field strength vs. frequency. Figure 4 The dependencies H c = H c ( f ) were fitted to a relationship, power law + free term, and thus H c = H c0 + c f 1/ν .…”