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The Ironless Inductive Position Sensor can be the ideal candidate for linear position sensing in harsh environment and in presence of external magnetic fields. Starting from the validated electromagnetic characteristics, this paper presents a model of thermal effects influencing the sensor's position reading and an effective algorithm to compensate them. The compensation is performed without affecting the nominal sensor's functioning and without using additional temperature probes, which would complicate the sensor's assembly. The model constitutes the basis of this algorithm, which is then validated through experimental measurements on a custom Ironless Position Sensor prototype.

The ironless inductive position sensor is a linear position sensing structure, which exhibits intrinsic immunity to external magnetic fields since it is characterized by air-cored windings. This new solution may be of major interest for applications where external magnetic fields can be a source of interference. In this paper, an analytical model of the working principle of the sensor is proposed. The effect of the moving coil flux on the overall sensed magnetic flux is described. The model is preliminarily verified by simulations on a finite-element structure of the sensor, in order to assess its soundness. Finally, experimental measurements on a custom sensor's prototype give the definitive benchmarking of the model as a valid design tool, in the framework of the design and synthesis of the device. © 1963-2012 IEEE.

The ironless inductive position sensor (I2PS) is a five-coil air-cored structure that senses the variation of flux linkage between supply and sense coils and relates it to the linear position of a moving coil. In air-cored structures, the skin and proximity effect can bring substantial variations of the electrical resistance, leading to important deviations from the low-frequency functioning. In this paper, an analysis of the effect of high-frequency phenomena on the I2PS functioning is described. The key-element is the modeling of the resistance as a function of the frequency, which starts from the analytical resolution of Maxwell's equations in the coil's geometry. The analysis is validated by means of experimental measurements on custom sensor coils. The resulting model is integrated with the existing low-frequency analysis and represents a complete tool for the design of an I2PS sensor, framing its electromagnetic behavior.