复合结构磁扭转微镜光纤电流传感器的研究

Study of Magnetic Torsion Micro-Mirror Fiber Current Sensors with Composite Structure

提出一种复合结构微机电系统(MEMS)磁扭转微镜光纤电流传感器,传感部分由磁扭转微镜和双光纤准直器组成。介绍了MEMS扭转微镜的结构及电流传感原理。对电流传感器模型进行分析,结果表明,选择合适的准直器端面与微镜的距离,可以避免信号失真。利用归一化光强峰峰值作为交变电流来测量输出信号时,电流测量灵敏度随电流测量值的变化而变化,且被测电流的电流强度接近0时,测量灵敏度也接近0。因此采用归一化光强线性矫正信号处理方法,得到了很好的输出线性响应曲线,使电流测量灵敏度不受电流变化的影响。最后实验验证了理论分析和模拟仿真结果的正确性,实验测得的归一化光强线性矫正响应灵敏度约为0.034/A。

A MEMS （micro-electro-mechanical system） magnetic torsion micro-mirror fiber current sensor with composite structure is proposed. The sensor part is composed of a magnetic torsion mirror and a dual-fiber collimator. The structure of MEMS magnetic torsion micro-mirror and the principle of current sensor are introduced. Analysis based on the current sensor model shows that by choosing suitable distance between the collimator and the micro-mirror, signal distortion can be avoided. When the peak-to-peak value of normalized intensity is taken as the output signal of alternating current measurement, the measurement sensitivity changes with the measured value of electric current. When the measured current approaches 0, the sensitivity also approaches 0. Thus, one linear correction processing method for normalized intensity signal is proposed. With this method, a good linear response curve is obtained, and the current measurement sensitivity is not distorted by the current change. Finally, the correctness of theoretical analysis and simulation results are testified by experiments, from which the linear response sensitivity of normalized intensity reaches around 0. 034/A.