Eddy current losses and number of domain walls with respect to total number of layers for very thin 3% Si-Fe strip-wound cores

The relation between the domain wall motion and the eddy current losses of very thin (110)[001] 3% Si-Fe strip-wound cores were investigated. The measured eddy current losses were larger than those estimated using a modified Pry and Bean model in the frequency region 50-500 Hz. It is known that the domain walls of thick (110)[001] 3% Si-Fe strips move nonuniformly in the low-frequency range (0.1-100 Hz), but this frequency range is lower than that usually used for very thin strips. By measuring the flux voltage in every layer, we found that the voltage waveforms were not sinusoidal, even if the secondary voltage waveform of the core was sinusoidal, and the magnitude of the voltage in each layer was not uniform. These results indicate that the domain wall motion of very thin strips is not uniform, even at 50-500 Hz. The nonuniformity of the domain wall motion makes the eddy current losses larger than those estimated by means of the modified Pry and Bean model.