Characterization of Magnetic Immunity of an Ironless Inductive Position Sensor

Modeling of High-Frequency Electromagnetic Effects on an Ironless Inductive Position Sensor

“…Each grey rectangle represents a coil layer. (2) where E φ and H z are the components of electric and magnetic fields in the coil layer along the φ and z directions respectively. The components along the other directions are null, given the hypotheses.…”

“…1) [1]- [2]. It can be used as a valid alternative in harsh environments (as nuclear plants, plasma control or particle accelerators [3]) to Linear Variable Differential Transformers (LVDT) [4] or other inductive position sensors [5]- [6] when external DC/slowly-varying magnetic fields are also present [7]- [8].…”

“…It can be used as a valid alternative in harsh environments (as nuclear plants, plasma control or particle accelerators [3]) to Linear Variable Differential Transformers (LVDT) [4] or other inductive position sensors [5]- [6] when external DC/slowly-varying magnetic fields are also present [7]- [8]. As a matter of fact, the I2PS keeps the properties of long lifetime, robustness [9]- [10], radiation-hardness [11] and good precision (with proper conditioning algorithms [12]) typical of LVDTs [13], introducing also the immunity to external magnetic fields, which have shown to affect the LVDT readings [8] due to the presence of magnetic materials in the sensor's structure [14].…”

“…Thus, the two sense voltage amplitudes are non-equal and according to their difference, one can extract the moving coil position. Being the sensor totally air-cored, an external DC/slowlyvarying magnetic field has no effect on the AC voltages [14].…”

“…On the contrary, experimental studies have demonstrated the immunity of I2PS to such fields (the drift stays always within the measurement uncertainty [1]- [2]). Such empirical verification further confirms the advantage of this solution with respect to standard LVDTs.…”