Modeling of moving coil capacitance in an ironless inductive position sensor

The Ironless Inductive Position Sensor has been introduced as a valid choice for precise and accurate position sensing in harsh magnetic environments. It is made of 4 fixed coils and one moving coil and presents complete immunity to external interfering magnetic fields. This paper introduces the model of the stray capacitance of the moving coil, since the presence of such parasitic capacitances can seriously affect the choice of the supply frequency in the sensor design optimization. The model results are then compared with experimental measurements. The model constitutes the starting point for the complete capacitance analytic description of the sensor.