An improved calculation of ferrite core loss for nonsinusoidal waveforms separates a flux trajectory into major and minor loops via a new recursive algorithm. It is highly accurate and outperforms two previous methods for our measured data. The only characteristics of the material required are the standard Steinmetz-equation parameters.

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Accurate prediction of ferrite core loss with nonsinusoidal waveforms using only Steinmetz parameters

An extension to the Steinmetz equation is proposed, to enable estimation of hysteresis losses in magnetic core materials with nonsinusoidal flux waveforms The new formulation is shown to avoid anomalies present in previous modified-Steinmetz-equation calculations of loss with nonsinusoidal waveforms Comparison with experimental measurements in MnZn ferrite shows improved accuracy The result may be optionally formulated in terms of an effective frequency and an effective amplitude, and options for defining these are discussed

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Improved calculation of core loss with nonsinusoidal waveforms

The need for protecting human or devices from harm and for keeping something from being detected by other instruments is spawning a world of attention in the development of novel electromagnetic (EM) wave absorption materials An ideal EM wave absorber is necessary to have light weight, thin thickness, high EM wave absorption, broad width, tunable absorption frequency, and multi-functionality This article introduces the EM wave absorption mechanism and reviews the development of polymer-based nanocomposites for EM wave absorption, in which polymers act as absorbing components or/and matrixes And we also summarize the approaches to design the ideal absorber, including introduction of nanostructure, and simultaneous action of both dielectric and magnetic materials with special structure by directly mixing, core–shell or multilayer structure

Polymeric nanocomposites for electromagnetic wave absorption

This paper presents a practical method for predicting the core losses in magnetic components for an arbitrary shape of the magnetizing current. This theory is based on a weighted time derivative of the magnetic flux density and offers the possibility to use the suppliers data, normally derived from measurements with sinewave currents, also for the real current shapes occurring in switch mode power supplies. By means of a special full-bridge power converter, a test setup is developed that allows the verification of the equations derived in this paper.

Calculating core losses in transformers for arbitrary magnetizing currents a comparison of different approaches

Nonsinusoidal voltage waveforms are quite common in high frequency power conversion magnetics. Low frequency nonsinusoidal waveforms are also common in ac motor applications with waveforms such as pulsewidth modulation and six-step. Previous attempts to model these losses, based on the Steinmetz equation, can work only in a limited range of frequencies, flux density excitations, and waveforms. In this paper, we present a very practical, yet very general and accurate model, for core loss calculations in case of nonsinusoidal voltage waveforms. We show the model is equally applicable to low and high frequencies, metallic as well as nonmetallic (e.g., ferrites) core materials, by comparing the model prediction with measured data for various waveforms, frequencies, and flux densities. The model can be used for the design of high frequency transformers and inductors for use in switched mode power supplies. The model can also be used for ac motors where it is hard to estimate "derating factor" and to avoid uncontrolled temperature rise

A Practical, Accurate and Very General Core Loss Model for Nonsinusoidal Waveforms

A practical method is presented for computing high-frequency ferrite core losses in the magnetic component for arbitrary voltage waveforms. The model presented requires only a few material parameters as input. To calculate ferrite hysteresis losses, a model based on empirical rules is employed. For high-frequency eddy current losses, a built phenomenon is assumed. It is demonstrated that the hysteresis model reproduces all of the important known features of the soft ferrites. These features include hysteresis loop shapes for low- and high-field excitations, the nonlinear permeability behavior, and hysteresis loss dependence on the amplitude of the exciting field. It is found that the total calculated core loss as a function of frequency and flux density correctly describes the observed soft ferrite behavior. The theoretical results are compared with available data for two commercial ferrites, and good agreement is found up to fairly high frequencies ( approximately 500 kHz). >

W. Roshen

Papers

Ferrite core loss for power magnetic components design