Accuracy Analysis of Sensing Coils in 2-D Magnetic Properties Measurement

Abstract

There has been an increasing awareness of research on magnetic properties of soft magnetic materials. In reality, the soft magnetic materials are likely to be magnetized by 2-D rotating magnetic field. Moreover, the magnetic properties could be influenced by mechanical stress. In order to investigate the magnetic properties thoroughly, numerous measurement apparatuses have been developed, which could take rotating magnetic flux or mechanical stress into account. However, there is limited research on the investigation of 2-D magnetic properties affected by laminated direction mechanical stress, as few mature devices could be employed, since the traditional $B$ – $H$ sensing coils are easily damaged by laminated direction stress. Therefore, the sensing structure with cubic specimen is proposed for 2-D magnetic properties measurement considering laminated direction stress. The printed circuit board (PCB)-based $B$ – $H$ sensing coils, which are attached to the surrounding surface of the cubic specimen, could be free of the impact of the $z$ -direction mechanical stress. The accuracy of $B$ – $H$ sensing part is analyzed in detail by means of the finite-element method as well as experiments. And, more remarkable, the deficiency of the artificial $H$ -coils wound by enameled wire is presented. Hence, a modified $H$ -coil made of four layer PCBs is proposed in this paper, the measurement accuracy is proven through experiments.