Power losses in thick steel laminations with hysteresis

Abstract

Magnetic power losses have been experimentally investigated and theoretically predicted over a range of frequencies ͑direct current-1.5 kHz͒ and peak inductions ͑0.5-1.5 T͒ in 1-mm-thick FeSi 2 wt. % laminations. The direct current hysteresis properties of the system are described by the Preisach model, with the Preisach distribution function reconstructed from the measurement of the recoil magnetization curve ͑B p ϭ1.7 T͒. On this basis, the time behavior of the magnetic induction vs frequency at different lamination depths is calculated by a finite element method numerical solution of Maxwell equations, which takes explicitly into account the Preisach model hysteretic B(H) relationship. The computed loop shapes are, in general, in good agreement with the measured ones. The power loss dependence on frequency is predicted and experimentally found to change from a ϳf 3/2 to a ϳf 2 law with increasing peak induction.

Dependence of the power losses of a non-oriented 3% Si-steel on frequency and gauge

“…It is noted that for d ¼ 0:978 mm, the skin effect is already apparent at 50 Hz. Theoretical calculations have given the same result [6]. For the 2.06 mm sample, f lim could not be estimated since ðW À W cl Þ versus ffiffi ffi f p does not show a linear regime in the studied frequency range.…”

“…When deriving the above equations full flux penetration was assumed, but at high frequencies the skin effect is no longer negligible. The local induction varies across the thickness, which makes the loss separation invalid [6,7]. The dynamic losses will not have the same dependence of J p on f and the hysteresis loss per cycle will not even be frequency independent.…”

Improved Design of Motors for Increased Efficiency in Residential Commercial Buildings

“…However, it also can be seen from fig. 2.6 that the classical eddy current loss formula overestimates loss when frequencies are higher than the critical frequency as demonstrated in [8,9]. This explains why excess losses are significant in thin steels and negligible in thick steels [9].…”

A simple scalar model for magnetic hysteresis

“…When we need dynamic hysteresis behavior, the eddy currents in the lamination must be considered by solving the field equations inside sheets as it is done for example in [1]. However, such an approach leads to a high computation time.…”

“…1) during magnetic material tests. The magnetizing cycle for the intrinsic induction of ferromagnetics is defined (1) where and are the flux density and field strength and the permeability of vacuum.…”