Multimodal iron loss analyses based on magnetization processes for various soft magnetic toroidal cores

Abstract

Since iron loss of soft magnetic devices has been one of the major energy loss components in a modern power electronics system, it is crucially important to understand the physical mechanisms of iron loss. For this issue, the classical Steinmetz equation-based analysis has been widely utilized for the iron loss decomposition into hysteresis loss, classical eddy current loss, and excess loss. In this study, multimodal iron loss analyses based on magnetization processes were adopted for Mn-Zn ferrite sintered core, FINEMET wound core, and previously reported Sendust powder core [N. Ono et al., IEEE Trans. Magn. 59, 6301305 (2023)], which have quite different magnetic and electronic properties. These analyses revealed that all the cores studied in this work commonly exhibited to change the magnetization process from irreversible to reversible with increasing the frequency, which correspond to magnetic domain wall displacement and magnetization rotation, respectively. The transition frequency of the magnetization process significantly depends on the samples. The classical Steinmetz based analysis and the statistic model which is the theory to explain the excess loss were compared with the above iron loss analyses. Consequently, the iron loss components of irreversible and reversible magnetization processes are well consistent with the sum of hysteresis and excess losses and the classical eddy current loss, respectively. Moreover, the magnetic object introduced as a conceptual parameter of the statistic model corresponds to the effective domain wall number.