# Advances in core loss calculations for magnetic materials

01 Jan 1982-Vol. 83, pp 11446

TL;DR: In this article, a new analytical technique which predicts the basic magnetic properties under various operating conditions encountered in state-of-the-art dc-ac/dc converters is discussed.

Abstract: A new analytical technique which predicts the basic magnetic properties under various operating conditions encountered in state-of-the-art dc-ac/dc converters is discussed. Using a new flux-controlled core excitation circuit, magnetic core characteristics were developed for constant values of ramp flux (square wave voltage excitation) and frequency. From this empirical data, a mathematical loss characteristics equation is developed to analytically predict the specific core loss of several magnetic materials under various waveform excitation conditions. In addition, these characteristics show the circuit designer for the first time the direct functional relatonships between induction level and specific core loss as a function of the two key dc-dc converter operating parameters of input voltage and duty cycle.

##### Citations

More filters

••

02 Oct 1988TL;DR: Chopper-driven operation of a conventional, series-connected DC machine is examined for the purpose of studying operating efficiency of the chopper circuit and DC machine.

Abstract: Chopper-driven operation of a conventional, series-connected DC machine is examined for the purpose of studying operating efficiency of the chopper circuit and DC machine. After expressions are developed for the steady-state circuit waveforms, component loss models are developed, and losses predicted for differing values of switching frequency and DC input voltage to the chopper circuit. Results show that most efficient operation of the chopper circuit and DC machine occurs with high-frequency operation. >

##### References

More filters

••

TL;DR: In this article, a simple and practical method of correcting the hysteresis loss in a thin lamination for the effects of minor loops is described, and the necessary correction is applied to the losses that would occur under conditions of sinusoidal flux density.

Abstract: A simple and practical method of correcting the hysteresis loss in a thin lamination for the effects of minor loops is described. The necessary correction is applied to the losses that would occur under conditions of sinusoidal flux density and the required empirical factor is derived using a broad range of loss measurement data. It is shown that the correction, to a very good approximation, varies linearly with the unweighted algebraic sum of the flux density reversals in the driving waveforms. Used together with a similar factor that corrects the eddy current component of loss for the effects of flux density harmonics, the total loss can be easily estimated to an accuracy of less than 5%.

180 citations

••

TL;DR: In this paper, an attempt is made to describe recent progress in this field of study, and experimental domain observations are described which explain the optimum thickness of transformer steel for minimum loss and the variation of power loss with applied stress.

Abstract: The observation of the domain pattern of 3% grain-oriented silicon-iron (transformer steel) by the Kerr magneto-optic effect has enabled a greater understanding of the basic magnetization processes of this material to be obtained. In this review paper, an attempt is made to describe recent progress in this field of study. The principal commercial criterion of transformer steel is the power loss and therefore many attempts have been made to correlate the domain observations with measured loss. The increased knowledge of the shape of the loss per cycle against frequency characteristic has shown that the anomalous loss is responsible for approximately 50% of the total loss. Experimental results are described which attribute the anomalous loss to many causes such as the occurrence of domain walls, domain wall angles and configuration, variation of wall spacing with lamination thickness, non-uniform and non-repetitive wall motion (pinning), grain size effects, lack of flux penetration (wall bowing) and domain nucleation. In addition, experimental domain observations are described which explain the optimum thickness of transformer steel for minimum loss and the variation of power loss with applied stress.

56 citations

••

TL;DR: In this paper, the authors considered the problem of estimating the core losses in a thin magnetic steel lamination when the driving flux contains not only the fundamental, but also odd harmonic components.

Abstract: This paper considers the problem of estimating the core losses in a thin magnetic steel lamination when the driving flux contains not only the fundamental, but also odd harmonic components. Two numerical methods of predicting the eddy current losses due to an arbitrary flux waveform are briefly described. The important case of 3rd harmonic distortion is specifically considered. The digital simulations are used to develop a very simple model that describes the eddy current and hysteresis losses under the assumed distortion conditions with good accuracy.

56 citations

### "Advances in core loss calculations ..." refers background in this paper

...N n + 1 + W—sec (12) ET oEi = + SCLi ĝ<---cyCl i=1 2nf i=1 Similarly the total energy for the negative cycle is...

[...]