Sensorless direct torque control of interior permanent magnet synchronous motor drives using the current derivative approach

This paper presents a sensorless direct torque control (DTC) scheme for interior permanent magnet synchronous motors (IPMSMs) drives over a wide speed range including very low speeds. The stator flux observer comprises the voltage model augmented by the current model. The position information required by the current model is derived from the examination of the stator current response due to machine saliency. Unlike the signal injection method, the proposed method utilizes only the applied voltage vectors to the machine stator windings. The simulation results presented verify the effectiveness of the proposed approach.