一种采用压电矩形鼓和永磁铁的小型电流传感器研究

Research on a Mini-Type AC Current Sensor Using Piezoelectric-Drum and Permanent Magnet

提出了一种采用压电矩形鼓和永磁铁的小型电流传感器。基于安培定律,永磁铁感受电流变化并驱动压电矩形鼓振动,压电矩形鼓因压电效应将振动转化为电信号输出,从而实现电流传感。利用有限元分析方法研究了电流传感器的一阶振动模态及其应力分布,并计算了电流传感器的灵敏度频率响应特性,其与实验结果较吻合。实验结果表明,该电流传感器在一阶谐振频率204 Hz处具有较高的灵敏度(0.95 V/A),在动态范围0.005 A～30 A内具有良好的线性度(0.3%);与采用压电悬臂梁结构的电流传感器相比,具有更好的稳定性。文中提出的传感器结构还可以应用于振动信号、磁场的长期不间断测量或监测。

A novel mini-type AC current sensor using piezoelectric-drum and permanent magnets is presented. Due to Ampere's law,the vibration of a permanent magnet is induced under the effect of AC current,and then deformations occur on the piezoelectric drum by this vibration. Consequently,voltage output from the piezoelectric drum and current sensing are achieved due to the piezoelectric effect. The fundamental mode of the proposed sensor and its stress distribution at this mode are theoretically studied and the current sensitivity related to frequency for the sensor is also calculated by using the finite element methods. The analysis results agree with the experimental data. The experiments show that this proposed sensor has a sensitivity of 0.95 V/A at the first-order frequency of204 Hz,a good linearity of 0.3% among a current range of 0.005 A^30 A,and better stability than the conventional current seonsor with piezoelectric cantilever beams. The structure of the presented sensor can be further used in the fields of the long-time continuous measurement or monitoring for the signal of vabration or magnetic field.