Direct torque control of permanent magnet synchronous motor

Direct torque control (DTC) is a method to control motor with utilizing torque and flux. But the torque and current ripples are occurred in the conventional DTC. Reason of undesired torque and current ripples is low number of voltage vectors applied to the motor controlled by the conventional DTC technique. In this paper, DTC of the PMSM has been analyzed. The stator flux and voltage space vectors are studied and the simulation of the DTC is realized. Base on the analysis of basic DTC of permanent magnet synchronous motor (PMSM), a new DTC technology based on flux error vector (FEV-DTC) is proposed to reduce torque and flux ripples in this paper. Simulation and experimental results from the conventional DTC and FEV-DTC are presented and compared. Result shows that the torque and flux ripples are decreased in new DTC.