Electrical and mechanical performance difference on piezoelectric segmentation in a passive MEMS DC current sensor applicable to two-wire DC appliances

Abstract

As society develops in intelligence, DC is being widely used in all kinds of field in modern life, which means that a sensitive and convenient DC sensor is necessary to monitor it. Compared with other kinds of current sensor, the proposed passive MEMS DC current sensor has several significant features: power-free passive sensing, small size and low cost. In this work, the performance difference of a cantilever-based bending MEMS DC current sensor among three segmentation PZT plates was first experimentally discovered. The distribution difference of X-dir (X-direction) stress along the Y axis is confirmed through FEM analysis. An optimized structure with two slots at the root of the cantilever has been proposed to minimize the difference of average X-dir stress on an area attached to three PZT plates. A nearly linear relationship between the output voltage Voutput and the AC current has been obtained through both theoretical calculation and experimental verification. The sensitivity of the developed MEMS DC current sensor is 40–25 mV A−1 in the current range of 0–400 mA. It is found that there is a good consistency among the calculation, experiment and simulation results.