A general method for designing low-temperature drift, high-bandwidth, variable-reluctance position sensors

A method was developed to design high-bandwidth single-ended variable-reluctance position sensors with high accuracy and extremely low temperature drift for use in magnetic bearing control systems. The method was used to design a hermetic radial position sensor with a position sensitivity (
{1/L_{0}}{dL/dx}
) of 1 percent/µm over the range of 0-50 µm and a temperature drift (
{1/L_{0}}{dL/dT}
) of less than 0.02 percent/°C over the range of 0-100°C, i.e., less than a 2-µm position error for a temperature variation of 100°C.