Experimental evaluation of the influence of DC-premagnetization on the properties of power electronic ferrites

Abstract

In many power electronic applications ferrite cores of magnetic components are biased with a DC or low-frequency premagnetization. Usually however, the influence of t h e bias on t h e losses and permeability is not considered in t h e component design. This paper describes a precise measurement setup t o determine t h e power losses and t h e magnetization curve of premagnetized ferrites. The measurements on typical ferrites of two major manufacturers prove that the influence of a DC-bias on t h e material properties can not be neglected. The utilization of a ferrite is if a DC-bias is applied to the component.

Analysis of Rotor Core Eddy-Current Losses in Interior Permanent-Magnet Synchronous Machines

“…The magnetic flux waveform in the rotor of the synchronous machine is biased with dc premagnetization. The influence of dc premagnetization on the losses of ferrites has experimentally been evaluated in [11]. It has been shown that this influence cannot be neglected and must properly be incorporated to achieve accurate results.…”

“…These curves are typically based on Epstein frame measurements with samples of the iron lamination material at various frequencies using a sinusoidal magnetic field. By assuming sinusoidal variation of the magnetic field, this conventional method ignores the effects of the following: 1) minor loops on the hysteresis losses [10]; 2) dc bias on the hysteresis losses [11];…”

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

“…These nonsinusoidal waveforms result in different losses [4], [5], [6]. DC bias can also significantly affect loss [7], [8], [9]. A better method of determining loss, accurate for a wider variety of waveforms, is needed.…”

Basic investigation on core loss calculation method under square wave voltage magnetizing condition

“…However, in the case of DC-DC converter application, flux waveforms of inductors are triangle waves because of square wave voltage magnetizing condition. Hence, the core loss frequency characteristic graph based on Steinmetz equation cannot provide accurate core loss because non-sinusoidal magnetizing waveform is not considered [7], [8].…”