Design Optimization of a Position Sensor for Linearity Range Extension

This article presents a magnetic design-optimized model of a linear variable differential transformer (LVDT) sensor with short coils and long armatures. The sensor has one excitation coil and two antiserially connected pickup coils located between two parallel armatures’ plates. A developed 3-D analytical method and the finite element method (FEM) are used for magnetic analysis and design optimization of an LVDT sensor. The structure of the armatures is optimized to enhance the linearity range of the LVDT sensor. The rectangular shape of the armature has been changed to a trapezoidal shape to decrease the nonlinearity error and extend the linearity range. The measured nonlinearity error is as low as 1.0% for the ±90 mm movement range.