2-D Magnetic Properties Measurement System for Electrical Steel Sheets Considering Laminated Direction Mechanical Stress

Abstract

The 2-D rotating magnetic field is demonstrated in electrical steel sheets, which are widely used in iron cores of motors, etc. In addition, the magnetic properties of a motor iron core are strongly affected by the compressive stress in the laminated direction induced by welding, bolt bundles, etc. In order to investigate the rotating magnetic properties of the material under laminated direction stress, a novel magnetic properties measurement system is developed in this paper. The compressive stress is loaded on cubic specimen in the laminated direction. A novel sensing structure with combined magnetic flux density $B$ and magnetic field strength ${H}$ sensing coils is developed with an assistance of a four-layer printed circuit board. Such structure yields more accurate ${B}$ and ${H}$ measurement. The accuracy of magnetic properties measurement of the apparatus is validated by finite-element analysis. Except for investigating the correlation between the compressive stress and its magnetic properties of the electrical steel sheets, the coupling relationship between the magnetic property in ${x}$ -axis direction and the counterpart in ${y}$ -axis direction is found in 2-D rotational magnetization. Furthermore, the impact of the compressive stress on the coupling relationship is explored. The experimental results are reported, and the mechanism analysis is employed to discuss the results.