A Modified Characterization Method for Core Loss Calculation Under Rotational Magnetization

Magnetic materials, as a key component used in electrical equipment, directly determine the equipment performance. The total core loss formula derived by the Poynting vector represents the flow of electromagnetic energy through a closed surface, but it does not include the energy consumption of heat due to eddy current. Also, the permeability of magnetic materials is not uniform in the period of magnetization, even for isotropic materials. This study derives the electromagnetic energy formula considering tensors of permeability and permittivity, and the modified total core loss formula is given. The formula contains three components. The first component is the modified form of the Poynting vector, the second component is the expression of eddy current loss, and the third component is the loss between the axial directions under rotational magnetizations. The experiments of nonoriented silicon steel B35A210 at 20, 50, 100, and 200 Hz are carried out on a 2-D magnetic properties measurement system. The experimental results are compared with the theoretically derived results to understand the eddy current loss and hysteresis loss.