Research and Development > JFE TECHNICAL REPORT > No.16 Special Issue on “Engineering,” “Steel Section Products,” and “Iron and Steel Powders” > High Performance MnZn Ferrites for Transformer Core Used in Forward Mode Switching Power Supply

No.16 Special Issue on “Engineering,” “Steel Section Products,” and “Iron and Steel Powders”

High Performance MnZn Ferrites for Transformer Core Used in Forward Mode Switching Power Supply

GOTOH Satoshi   OTAKE Toshiaki   FUKUDA Yutaka   TOGAWA Jirou

Abstract

Low loss MnZn ferrites which have been developed until now for transformer cores in switching power supplies were introduced with future development trends. In addition to the improvement on core loss and saturationmagnetic flux density, the temperature and frequency dependence of the core loss have been particularly improved in new materials, MBT3 and MBF4, respectively. The most suitable material for enhancing the power supply efficiency of a commercial forward mode switching power supply was evaluated in comparison with the current materials, MB3 and MB4. The efficiency increased in the order of MB3≤MB4<MBT3≤MBF4.Although MBT3 shows the lowest loss under the sinusoidal flux condition, the highest efficiency can be obtained as using MBF4, which shows lower harmonic losses derived from the rectangular wave voltage in the actual power supply due to the excellent frequency dependence of the core loss.

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