Measurement and Analysis of Magnetostriction of Nanocrystalline Alloy Laminations under Medium-frequency Excitation
Changgeng Zhang1,2*, Haitao Zhang1,2, Tao Chen1,2, and Yongjian Li1,2
1State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300401, China
2Hebei Key Laboratory of Equipment and Technology Demonstration of Flexible DC Transmission, Hebei University of Technology, Tianjin 300401, China
* Corresponding author: changgeng.zhang@hebut.edu.cn
Abstract
Nanocrystalline alloys, widely used as core materials of medium-frequency transformers, require accurate measurement of their magnetostriction to calculate the core vibration and noise during the transformer design phase. A synchronous measuring system consisting of a magnetizer with an optical reflector and a laser vibrometer is constructed to measure the 1D magnetic loss and magnetostriction properties under medium-frequency excitation. The annealed nanocrystalline alloy sheets are laminated and measured in this study due to their softness and brittleness. The influence of single- and double-yoke magnetic circuit structures on the measurement of magnetic properties is discussed. The hysteresis loops and magnetostriction of nanocrystalline alloy laminations with a double-yoke structure are measured from 1kHz to 10kHz. The results indicate that the hysteresis loops widen as the frequency increases, resulting in increased losses. Moreover, the peak-to-peak value of magnetostriction first increases and then decreases with increasing excitation frequency, and the magnetostriction curves exhibit a transition from elongation to contraction. These results can provide data support for the design of cores for medium-frequency electromagnetic devices.