Modeling Magnetostriction of Grain-Oriented Sheet Steels Based on Magnetization Process and Domain Motion

Grain-oriented (GO) sheet steels are preferred for magnetic cores in large power transformers because of their low core loss and high permeability. However, GO sheet steels exhibit more complex magnetostriction than nonoriented (NO) materials, causing undesirable vibrations and acoustic noises in the transformer core, especially under certain operating conditions, such as DC bias and magnetic saturation. This paper proposes a magnetostriction model of GO sheet steels based on an improved understanding of the magnetization process and domain motion. Incorporating the positive and negative magnetostriction components attributed to domain wall motion and rotation, the proposed model can accurately reproduce the butterfly loops in a wide range of magnetization along the rolling direction (RD) of GO material. Its effectiveness and accuracy are verified by the experimental measurements.