Virtual rotor grounding of capacitive angular position sensors

This paper presents a new approach for the design of capacitive angular position and angular speed sensors. The idea is to obtain nonconductive grounding of the rotatable part of the sensor. This approach allows the use of conductive rotor blades fixed to a nonconductive shaft. A simple prototype has been developed to show the theory of operation. Model calculations and experimental results show that virtual grounding allows neglecting the rotor-ground resistance in a wide range.