Optimisation of LVDT signal using phase synchronisation adjustment

Abstract

This paper reports optimization of an LVDT output signal using phase synchronization adjustment. The output signal of an LVDT that incorporates its sign or displacement direction are usually obtained by using a synchronization between the excitation and secondary output signal using a phase-sensitive rectifier. However, the phase of the excitation signal might not be perfectly matched with the phase of the second output signal of LVDT. This causes the rectifier to pass a small portion of the opposite polarity signal beyond the zero lines. Consequently, the total output signal after integration to a dc signal could be reduced, which yields a reduced sensitivity. The implementations of the phase synchronization adjustment methods could improve the performance of the output of the LVDT. The adjustment removes the signal beyond the zero line; thus, the dominant signal is not subtracted due to the leaked opposite sign signal. The adjustment of the phase synchronization to a certain phase angle provide the optimum sensitivity of the output of the LVDT and increase the sensitivity to 15% higher than the sensitivity without adjustment or zero phase shift.