Mr. Zolghadri et D. Roye, FULLY DIGITAL SENSORLESS DIRECT TORQUE CONTROL-SYSTEM FOR SYNCHRONOUSMACHINE, Electric machines and power systems, 26(7), 1998, pp. 709-721
A new sensorless controller based on direct torque control, for a sync
hronous machine is proposed. Using direct torque control, stator resis
tance is the only parameter of the machine which should be known. The
use of reactive torque control simplifies the field current control lo
op. Initial stator induced currents are used to estimate the initial s
tator flux. The outputs of the control system are switching commands o
f stator inverter and rotor chopper.