Pulsed eddy current has attracted increasing attention to ferromagnetic metal material evaluation since it possesses low power consumption and abundant frequency spectrum advantages. However, when a current source is applied to generate the pulse excitation signal in eddy current testing, the inductance of driver coil induces a large reverse electromotive force in the excitation circuit, which distorts the pulse excitation signal as the excitation circuit hardly satisfies the severe power and stability requirements for counteracting the reverse induced electromotive force. Therefore, a pulsed eddy current field excited by a voltage-driven coil placed concentrically to a ferromagnetic casing is studied, and the analytic solutions of it are formulated in this paper. In contrast to current source based pulsed eddy current testing methods, the electromotive force induced by the coil's inductance and eddy current is analyzed. Furthermore, a new pulse excitation function is adopted and induced electromotive force equations of pick-up coils are formulated based on the superposition principle of magnetic field. Finally, the theoretical results are verified by experiments.

中文翻译：

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铁磁套管脉冲涡流检测时域建模分析

脉冲涡流由于具有低功耗和丰富的频谱优势，在铁磁金属材料评价中越来越受到关注。但是在涡流检测中使用电流源产生脉冲励磁信号时，驱动线圈的电感在励磁电路中感应出很大的反向电动势，使脉冲励磁信号失真，因为励磁电路很难满足苛刻的功率要求。和抵消反向感应电动势的稳定性要求。因此，本文研究了与铁磁外壳同心放置的电压驱动线圈激发的脉冲涡流场，并给出了其解析解。与基于电流源的脉冲涡流测试方法相比，分析了线圈的电感和涡流引起的电动势。此外，采用新的脉冲激励函数，根据磁场叠加原理，建立了拾波线圈的感应电动势方程。最后，通过实验验证了理论结果。