Modelling and simulation of synchro and synchro-to-digital converter for electrical motor drives

摘要

In this study, modelling and simulation of synchro and synchro-to-digital converter (SDC) are presented. This study is useful to estimate the shaft position and speed of induction motor using SDC through a synchro. The SDC uses scott-T circuit to convert three signals of synchro into two signals format. The position information of synchro shaft is present in peak amplitudes of scott-T outputs. A demodulator circuit is designed to extract the peak amplitude levels. The quadrant in which the shaft angle falls is determined by quadrant detector. On the basis of the peak amplitude levels and quadrant information, the synchro shaft angle is computed. This method provides shaft position and speed in digital form. The reuse of quadrant detector in the evaluation of shaft speed shows the effectiveness of the proposed scheme.