Decomposition of Magnetic Field Intensity in Ferrite Based on Time Derivative of Magnetic Flux Density and Power Loss

• Published in: Journal of the Magnetics Society of Japan 2020/07/01, Vol.44(4), pp.102-107
• Main Authors: Saotome, H., Washizu, T.
• Format: Article
• Language: English
• Subjects: Core loss; Decomposition; dynamic magnetic loss; Excitation; ferrite; Ferrites; Flux density; hysteresis loss; iron loss; Magnetic fields; Magnetic flux; Magnetic induction; Magnetic permeability; Magnetism; Power loss; temperature; Waveforms
• ISSN: 1882-2924; 1882-2932
• DOI: 10.3379/msjmag.2007R004

  A method for the power loss analysis for ferrite is required and is expected to lead to the development of low-loss ferrites. In the present paper, the magnetic field intensity in ferrite was decomposed into four components for the analysis. When the time derivative of the magnetic induction, dB/dt, is low, the magnetic field intensity is composed of only two components, Hu and Hh, which yield the magnetic flux and the hysteresis loss, respectively. At high-dB/dt excitations, magnetic field intensities, Hv and Hf, appear in addition to Hu and Hh, where Hv lowers the permeability and Hf causes the dynamic magnetic loss, respectively. The temperature characteristics of Hu, Hh, Hv and Hf differ, which implies that the hysteresis and dynamic magnetic losses are caused by different physical mechanisms. The function tables for Hu (B, Bm), Hh (B, Bm), Hv (B, dB/dt, Bm) and Hf (B, dB/dt, Bm) were obtained from measurements conducted at ferrite core temperatures of 20, 40, and 60 °C, where Bm is the maximum magnetic flux density. The tables were used to simulate the magnetic field intensity for the excitation when a sinusoidal waveform voltage was applied to a ferrite inductor. The simulation results show good agreement with the experimental results.