Performance Analysis of Spiral Based Inductive Position Sensor using Equivalent Circuit Model

Abstract

This paper presents a simple way to analyse the Resonant Inductive Position Sensor through a transfer function model. This is derived from equivalent circuit of both sine and cosine output spiral coils from the basics of magnetic coupling between excitation and resonator coils. In this model, the impedance of both sine and cosine output coils and the output voltage are predicted. This has been implemented in MATLAB environment through Graphical User Interface (GUI) along with its signal conditioning and algorithm to predict the linear position of the moving resonator which is attached with the target position to be measured. This design tool will reduce the design cycle time and expenses due to either lab experiment or Finite Element Analysis (FEA). The accuracy of the sensor is also predicted through an error calculation by comparing the measured results with actual position in ideal condition.