Micro Voltage Sensor Based on Coupling of Electrostatic Force and Piezoresistive Effect

This paper proposes a miniature voltage sensor based on the coupling of electrostatic force and piezoresistive effect. The measurement principle involves a vibrating diaphragm that produces vertical displacement under the action of electrostatic force, causing deformation in the piezoresistive beam. The piezoresistive effect causes a change in the resistance of the piezoresistive beam due to deformation, and this change is monitored to measure the voltage. A finite element model was established to simulate the theoretical relationship of sensor output., and the device is fabricated using MEMS microfabrication technology. Tests on the sensor's output response characteristics indicate that when the voltage frequency range varies from 50Hz to 1500Hz, the sensor's sensitivity reaches up to 0.1417 mV/V, with nonlinearity error maintained below 1.31^%The miniature voltage sensor designed in this paper has the advantage of not requiring additional driving structures or signals. Its output response characteristics align with theoretical analysis, demonstrating good linearity and sensitivity, making it highly promising for voltage sensing applications in smart grids.

I. Introduction

Massive data collection and processing are fundamental to achieving smart grid functionality. By extensively collecting voltage and current data in the grid, the structure of the grid can be optimized, enabling online monitoring and fault diagnosis of the power system and equipment. Traditional voltage data collection primarily relies on voltage transformers, but these conventional devices have significant limitations: 1) They are bulky and difficult to install; 2) They are not cost-effective for wide-area distributed measurement due to high costs; 3) They have limited functionality, making it difficult to measure higher-order harmonic signals in the grid [1], [2]. To overcome these limitations, many new sensors have been proposed, with optical voltage sensors and coupled capacitor voltage sensors being quite common. Optical voltage sensors leverage the electro-optic effect and fiber optic technology, offering advantages such as a compact design, excellent frequency response, and superior insulation properties. However, the manufacturing complexity and high cost of optical components hinder large-scale production, and their long-term stability and reliability are low [3].