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| Improved transformer model for output impedance of eddy-current sensor probe |
| LV Yun-teng, ZHU Chang-sheng |
| Department of Electrical Engineering, Zhejiang University, Hangzhou 310000, China |
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Abstract For the quantitative description of electromagnetic coupling between probe coils of eddy-current sensor and detected material, an improved transformer model was presented based on the transformer model that was brought out by DARKO V. By dividing the whole probe coils and eddy-current distributed areas in detected material in both axial and radical directions, the improved transformer model included all coil units, which were regarded as primary sides, and eddy-current units, which were regarded as secondary sides. The output impedance of probe coils was derived by solving voltage equations for all coil units and eddy current units. The comparison between calculation results from both transformer models and experimental results proved the validation of improved transformer model. It is proved that the improved transformer model, with relatively simple principles and accurate calculation results consistent with experiments, provides a convenient method to quantitatively analyze the influence of variables on output impedance of probe coil and a reference for design and application of eddy-current sensor．
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Published: 26 November 2014
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电涡流传感器探头输出阻抗的改进变压器模型
针对电涡流传感器的探头线圈与被测材料间电磁耦合的输出阻抗的定量计算问题,在DARKO V提出的变压器模型的基础上,通过将探头线圈与被测材料中涡流分布区域全部进行轴向与径向的划分,提出了以单元涡流与单元线圈为基础的改进变压器模型.通过求解包括所有单元涡流和单元线圈的电压方程组,得到探头线圈的输出阻抗.通过将改进前后变压器模型的计算结果与实测输出阻抗值相比较,验证了改进变压器模型的有效性.结果表明,改进变压器模型的计算值与实际吻合度高,能够定量分析参数变化对线圈输出阻抗的影响,对于电涡流传感器的设计与应用,具有一定的参考价值.
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