Time‐averaged and instantaneous magnetic loss characteristics of different products of electrical steel for frequencies of 16 2/3 Hz up to 500 Hz

Abstract

Traditionally, products of electrical SiFe steel are focussed on applications for frequencies of 50-Hz. However, the recent developments of electric drive systems yielded a strong extension of the range from f = 16 2/3 Hz up to ca. 500 Hz. In spite of high industrial relevance, the literature offers the corresponding data on the material's magnetic energy losses in very rare ways. This paper reports a first comparative, multi-parametric study on eight different steel products that comprise non-oriented steels (NO), grain-oriented steels (GO) and scribed grain-oriented steels (SGO). Consistently at IEC-standardized samples, they were analysed for the whole frequency range that was split into low frequency (LF) and medium frequency (MF), with 80 Hz as the border. Data is presented on time-averaged total losses P, on the corresponding hysteresis losses P H and eddy current losses P E . LF proved to be governed by P H and MF rather by P E , however, with strong variations. Further, instantaneous magnetization power functions p(φ) were determined for basic insights into the involved temporal developments of energy dissipation. GOsteels yielded profiles close to rectified co-sinus functions that can be fully attributed to dissipative losses. On the other hand, p(t) of NO-steels and SGO-steels prove to include negative segments that reflect potential energy power, in the course of alignments of atomic moments in instants of high induction. Examples of industrial relevance of the accumulated data are steel production technology, product categorization, failure tracing and energy conversion. K E Y W O R D Seddy current effects, grain orientation, hysteresis losses, instantaneous losses, instantaneous power, magnetization power, silicon iron | INTRODUCTIONElectrical steel sheets of silicon iron are of high industrial relevance, due to their almost universal use for soft magnetic cores of electric machines. Traditionally, the production of core steel is focussed at applications for grid frequencies f of 50 and 60 Hz, respectively. As a matter of fact, almost all literature on aspects of magnetic energy losses are concentrated on these values. On the other hand, in recent times, word-wide developments were started to implement electric drive systems in general ways. This involves a large range of frequency f, starting with 16 2/3 Hz, up to 400 Hz. In some detail, it includes the following frequency key values: 16 2/3 Hz for train drives 25 Hz for train drives in countries like North America 50 Hz world-wide, the most frequent general grid frequency 60 Hz the grid frequency in parts of America and Asia 80 Hz being relevant for f-controlled drives, among others 400 Hz for aircrafts, sub-marines etc. 500 Hz (or even higher) for currently developed drive systemsThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Giant Epstein Tester for Magnetic Energy Loss Measurements of Non-Annealed Domain-Refined Fe–Si

“…This orientation power value indicates spin orientation processes as needed for high instantaneous values of induction. According to [19,20,21], non-scribed highly oriented steel shows this spike in less pronounced ways. Theoretically, we interpret the orientation processes with instantaneous lancet domains, close to scribing regions as discussed in [22].…”

High-Frequency Fractional Predictions and Spatial Distribution of the Magnetic Loss in a Grain-Oriented Magnetic Steel Lamination

“…Simultaneous resolution of Equations ( 8) and (10) was possible through the concatenation in a unique expression (Equation ( 11)), similar to Equation (5) in [27] and constituted of H terms exclusively:…”

“…Still, the physical meaning of the anomalous diffusion and σ' the pseudo conductivity was unclear. The only way to derive Equation (10) was through fractional Maxwell equations. Such equations have already been mentioned in the scientific literature [32,33] but remain complex to justify physically.…”

“…Therefore, this solution was discarded in this new study. Just as Equations ( 8) and (10) were concatenated in [15], Equations ( 2) and ( 8) can be reformulated the same way; for this, dB/dt in Equation (8) has to be isolated:…”

“…The frequency dependence of GO FeSi's magnetic behavior, marked by phenomena such as the skin effect, defies simplistic representation through conventional modeling approaches. Despite decades of research spanning seminal contributions [9][10][11][12][13][14][15], the quest for a unified physical model capable of elucidating the dynamic B-H loop and power loss mechanisms remains elusive [16]. According to Bertotti's statistical theory of losses (STL), the loss per magnetization cycle W at magnetizing frequency f and maximum flux density B m can commonly be expressed as the sum of the static hysteresis loss W hyst , the classical eddy current loss W clas , and the excess loss W exc :…”