Design of a novel micromachined non-contact resonant voltage sensor for power distribution systems

This paper presents the design of a novel closed-loop resonant voltage micro-sensor based on micro-machined process for power distribution systems. With a phase and an amplitude closed loop feedback control, the sensor is designed to adjust automatically to operate at its resonant frequency for maximizing its vibration amplitude and hence sensitivity. Different from other resonators, in order to achieve better stability, another negative feedback loop is used to adjust the potentials of the voltage feedback electrodes until the motion of the shutter no longer induces a dynamic current and the loop is balanced. Prototyped by the SOI fabrication process, the MEMS device gives quality factor (Q) of approximately 31178 at a vacuum degree of ~0.05mTorr with lower actuation voltages (i.e., 200mV DC and 70mVp-p). In addition, the ability to measure both AC and DC voltage is a significant advantage of this sensor in comparison to other sensors, which can only measure either AC or DC voltage.