Vector control in synchronous machine drives

Direct and indirect vector control schemes for a nonsalient pole synchronous machine (with or without damper winding) drives are analyzed. The control schemes are implemented using either the stator flux or the rotor flux and field current. The dynamic equations for each control scheme are presented, and the controller design steps are outlined for each of the proposed schemes. The controllers considered are the on-off hysteresis and discrete PI types. The AC-drive behavior is studied for each control scheme in several steady-state and transient modes of operation. Digital simulation results are presented and analyzed. The control schemes using the on-off hysteresis controller are shown to provide very good performance. The discrete source current in the synchronous reference frame shows better performance than those in the stationary reference frame. The feedforward rotor flux control showed good performance