A new scheme to direct torque control of interior permanent magnet synchronous machine drives for constant inverter switching frequency and low torque ripple

Direct torque control (DTC) can produce quick and robust response, but it has the problems of large torque ripples and inconstant inverter switching frequency. This paper introduces a modified direct torque control based on the space vector modulation (SVM) for interior permanent magnet synchronous motor (IPMSM) drive. Two PI controllers regulate the flux and torque, respectively, and the inverter is controlled by the SVM technique in the proposed DTC system. Simulation results show that the performance of the proposed DTC system has been improved with respect to the conventional DTC. The DTC system can effectively reduce the flux and torque ripples.