Analysis on Iron Loss of Sendust Dust Cores Based on Magnetization Reversal Processes

Iron loss of soft magnetic materials has been a major part of energy loss in modern power-electronics systems. Iron loss has been usually analyzed phenomenologically, but its physical mechanism has not been well understood yet. In this study, the iron loss of Sendust dust cores was investigated by means of models based on magnetization reversal processes. Broadband iron loss and permeability measurements were performed by combining conventional two-coil and capacitive cancellation methods. As a result, irreversible and reversible magnetization processes are dominant for the lower and higher frequency regions, respectively, and the large increment of iron loss for the frequency higher than 1 MHz is attributed to the change in the magnetization reversal mode. Furthermore, this change in the magnetization reversal mode is well consistent with the change in the effective domain wall number with the frequency.