中国物理B ›› 2010, Vol. 19 ›› Issue (12): 120302-120302.doi: 10.1088/1674-1056/19/12/120302

• GENERAL • 上一篇    下一篇

Analytical solutions of transient pulsed eddy current problem due to elliptical electromagnetic concentrative coils

肖春燕, 张军   

  1. Department of Electrical Engineering, School of Automation and Electrical Engineering, Beihang University, Beijing 100191, China
  • 收稿日期:2010-03-19 修回日期:2010-07-09 出版日期:2010-12-15 发布日期:2010-12-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 50807001).

Analytical solutions of transient pulsed eddy current problem due to elliptical electromagnetic concentrative coils

Xiao Chun-Yan(肖春燕) and Zhang Jun(张军)   

  1. Department of Electrical Engineering, School of Automation and Electrical Engineering, Beihang University, Beijing 100191, China
  • Received:2010-03-19 Revised:2010-07-09 Online:2010-12-15 Published:2010-12-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 50807001).

摘要: The electromagnetic concentrative coils are indispensable in the functional magnetic stimulation and have potential applications in nondestructive testing. In this paper, we propose a figure-8-shaped coil being composed of two arbitrary oblique elliptical coils, which can change the electromagnetic concentrative region and the magnitude of eddy current density by changing the elliptical shape and/or spread angle between two elliptical coils. Pulsed current is usually the excitation source in the functional magnetic stimulation, so in this paper we derive the analytical solutions of transient pulsed eddy current field in the time domain due to the elliptical concentrative coil placed in an arbitrary position over a half-infinite plane conductor by making use of the scale-transformation, the Laplace transform and the Fourier transform are used in our derivation. Calculation results of field distributions produced by the figure-8-shaped elliptical coil show some behaviours as follows: 1) the eddy currents are focused on the conductor under the geometric symmetric centre of figure-8-shaped coil; 2) the greater the scale factor of ellipse is, the higher the eddy current density is and the wider the concentrative area of eddy current along y axis is; 3) the maximum magnitude of eddy current density increases with the increase of spread angle. When spread angle is 180o, there are two additional reverse concentrative areas on both sides of x axis.

Abstract: The electromagnetic concentrative coils are indispensable in the functional magnetic stimulation and have potential applications in nondestructive testing. In this paper, we propose a figure-8-shaped coil being composed of two arbitrary oblique elliptical coils, which can change the electromagnetic concentrative region and the magnitude of eddy current density by changing the elliptical shape and/or spread angle between two elliptical coils. Pulsed current is usually the excitation source in the functional magnetic stimulation, so in this paper we derive the analytical solutions of transient pulsed eddy current field in the time domain due to the elliptical concentrative coil placed in an arbitrary position over a half-infinite plane conductor by making use of the scale-transformation, the Laplace transform and the Fourier transform are used in our derivation. Calculation results of field distributions produced by the figure-8-shaped elliptical coil show some behaviours as follows: 1) the eddy currents are focused on the conductor under the geometric symmetric centre of figure-8-shaped coil; 2) the greater the scale factor of ellipse is, the higher the eddy current density is and the wider the concentrative area of eddy current along y axis is; 3) the maximum magnitude of eddy current density increases with the increase of spread angle. When spread angle is 180o, there are two additional reverse concentrative areas on both sides of x axis.

Key words: transient pulsed eddy current, analytical solution, elliptical electromagnetic concentrative coil, functional magnetic stimulation

中图分类号: 

  • 0350D