Large signal eddy current losses beyond 100kHz

Eddy current losses under large flux excitation in Mn-Zn ferrite cores and both polycrystalline and amorphous metallic cape cores of thickness 4μm to 28μm are measured in the frequency range up to 1MHz. Beyond 100kHz, the complex behaviors of magnetization in metallic cores as seen in the lower frequency range disappear and eddy current losses are only proportional to the square of both frequency and flux density. It is attributed to the conclusion that all of the nuclei of domains nucleate and the number of domain walls reaches a constant maximum value nmaxIn order to obtain cores with less eddy current losses in the high frequency range, not only the values of conductivity and dimensions should be small but also the value of nmaxshould be as large as possible. The ultra thin Supermalloy cores are superior to conventional ferrite cores in the dynamic characteristics.