A direct torque controlled permanent magnet synchronous motor drive without a speed sensor

This paper reports results of further investigation of the so called direct torque control (DTC) technique to interior permanent magnet (IPM) synchronous motor drives. This torque control technique for IPM motors requires no dq-axis current controllers and coordinate transformation networks. A completely sensorless IPM motor drive with DTC, which uses a novel speed estimator from the stator flux vector and the torque angle is presented.