Research on Space Vector Modulation method for improving the torque ripple of Direct Torque Control

Because the traditional direct torque control (Direct Torque Control, DTC) method can only uses six effective voltage vectors for the dual control of torque and flux, there exists a larger torque ripple. In addition, the inverter´s switching state remains unchanged in a number of sampling cycles in the control process, and hence the system switching frequency is not constant and the capacity of power devices can not be fully utilized. This paper presents a new method of the space vector modulation (Space Vector Modulation, SVM) which is applied to the traditional direct torque control. The new SVM-DTC has a simple structure and easy to be achieved in real conditions. Simulation results show that the method can effectively reduce the torque ripple and improve the system steady-state operating performance and ensure constant switching frequency of the inverter.