DC-DC converters in power supplies should exhibit both high efficiency and power density. Losses in these converters can be attributed to losses in its transformer and circuit. To improve the efficiency of a switching power supply, it is necessary to reduce losses in the transformer. As the use of SiC and GaN semiconductors is becoming more widespread, it is even more important to find a way to reduce the losses in a MHz drive transformer. The losses in these transformers are primarily due to copper and iron losses. These losses can be reduced by changing the winding wire and core of a transformer. In this paper, the authors propose fabricating the winding wire and core magnetic composite materials. These magnetic composite materials comprise microscale magnetic powders and binders. The authors propose using a magnetocoated wire, which is a winding copper wire that has had magnetic composite materials plated onto it. The iron-based metal composite core is made using magnetic composite materials, which can reduce eddy current losses that a core experiences during MHz driving. This paper describes our results for an LLC resonant converter using a magnetocoated wire and an iron-based metal composite core.

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The deformation of liquid‐crystalline spherulites of poly(γ‐benzyl‐L‐glutamate) (PBLG) in an electric field was investigated by light scattering, polarized‐light microscopy, and birefringence measurements. Under the polarizing microscope, the deformation was found to be dependent upon the field strength. The spherulites deformed perpendicular to the field. Above 75 V/cm in N,N‐dimethylformamide or 120 V/cm in 1,1,2‐trichloroethane, the deformed spherulites were transformed to rodlike textures. With increasing voltage, the rods gradually oriented parallel to the electric field. On the basis of the experimental results, models for affine deformation are proposed. With these models, light‐scattering patterns are calculated. The calculated and experimental patterns agree semiquantitatively.

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